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EUROPEAN COMMISSION DIRECTORATE-GENERAL JRC JOINT RESEARCH CENTRE Institute for Prospective Technological Studies Sustainable Production and Consumption Unit

Summary on Energy Efficiency issues in the BREF Series

September 2009

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INTRODUCTION The aim of this document is to summarise and gather, for the industrial sectors covered by the IPPC Directive, the available information on energy efficiency in a systematic and structured way. It complements the information provided in the ENE BREF. The IMPEL study 'Energy Efficiency in Environmental Permits' [IMPEL, 2003] consitutes the main bibliographic source for this document, in particular for the iron and steel, non-ferrous metals, pulp and paper, chlor-alkali, ferrous metals, glass manufacturing and industrial cooling systems industrial sectors. The information related to the cement, lime and magnesium oxide industries, has been mainly gathered from the CLM BREF review that was adopted by the EC at the 21st IEF meeting in April 2009. The present document will be updated when new information from a revised BREF is available and progressively to cover the rest of IPPC sectors.

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Table of Contents INTRODUCTION.......................................................................................................................................I 1 THE CEMENT, LIME AND MAGNESIUM OXIDE MANUFACTURING INDUSTRIES

BREF (CLM)...................................................................................................................................... 1 The importance of energy efficiency ................................................................................................... 1 Main processes/technologies related to energy efficiency (burning processes)................................... 1 Energy recovery or energy-saving techniques for the main processes (burning processes) ................ 3 Energy data and energy-saving techniques for other processes (lime hydrating and lime grinding)... 5 Best available techniques (BAT) ......................................................................................................... 5 Specific aspects for energy savings and energy recovery measures .................................................... 7 Recommendations for future studies ................................................................................................... 7

2 PRODUCTION OF IRON AND STEEL BREF (I&S) .................................................................. 9 The importance of energy efficiency ................................................................................................... 9 Main processes/technologies related to energy efficiency................................................................... 9 Energy recovery or energy-saving techniques for the main processes .............................................. 10 Energy data and energy-saving techniques for other processes......................................................... 10 Best available techniques (BAT) ....................................................................................................... 11 Specific aspects for energy savings and recovery measures .............................................................. 11

3 NON-FERROUS METALS INDUSTRY BREF (NFM) .............................................................. 13 The importance of energy efficiency ................................................................................................. 13 Main processes/technologies related to energy efficiency................................................................. 13 Energy recovery or energy saving techniques for the main processes............................................... 13 Energy data and energy-saving techniques for other processes......................................................... 13 Best available techniques (BAT) ....................................................................................................... 14 Specific aspects for energy saving and energy recovery measures.................................................... 15 Recommendations for future studies ................................................................................................. 15

4 PULP AND PAPER INDUSTRY BREF (PP) ............................................................................... 17 The importance of energy efficiency ................................................................................................. 17 Main processes/technologies related to energy efficiency................................................................. 17 Energy recovery or energy-saving techniques for the main processes .............................................. 18 Energy data and energy saving techniques for other processes ......................................................... 18 Best available techniques (BAT) ....................................................................................................... 18 General BAT...................................................................................................................................... 18 Process-specific BAT for the kraft pulp and sulphite pulp mills ....................................................... 18 Process-specific BAT for the mechanical and chemi-mechanical pulp and paper mills.................... 19 Process-specific BAT for recovered paper processing paper mills.................................................... 19 Process-specific BAT for paper mills ................................................................................................ 19 BAT associated consumption values ................................................................................................. 19 Specific aspects for energy savings and energy-recovery measures .................................................. 20 Recommendations for future studies ................................................................................................. 20

5 CHLOR-ALKALI MANUFACTURING INDUSTRY BREF (CAK) ........................................ 21 The importance of energy efficiency ................................................................................................. 21 Main processes/technologies related to energy efficiency................................................................. 21 Energy recovery or energy-saving techniques for the main processes/technologies ......................... 21 Energy data and energy-saving techniques for other processes......................................................... 21 Best available techniques (BAT) ....................................................................................................... 21 Specific aspects for energy saving and energy-recovery measures ................................................... 21

6 FERROUS METALS PROCESSING INDUSTRY BREF (FMP) .............................................. 23 The importance of energy efficiency ................................................................................................. 23 Main processes/technologies related to energy efficiency................................................................. 23 Energy recovery or energy-saving techniques for the main processes .............................................. 23 Energy data and energy-saving techniques for other processes......................................................... 23 Best available techniques (BAT) ....................................................................................................... 24 General BAT...................................................................................................................................... 24 Process-specific BAT ........................................................................................................................ 24 Specific aspects for energy savings and energy-recovery measures .................................................. 25 Recommendations for future studies ................................................................................................. 25

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7 GLASS MANUFACTURING INDUSTRY BREF (GLS)............................................................ 27 The importance of energy efficiency ................................................................................................. 27 Main processes/technologies related to energy efficiency................................................................. 27 Energy recovery or energy-saving techniques for the main processes .............................................. 27 Energy data and energy-saving techniques for other processes......................................................... 27

8 INDUSTRIAL COOLING SYSTEMS BREF (ICS)..................................................................... 29 The importance of energy efficiency ................................................................................................. 29 Main processes/technologies related to energy efficiency................................................................. 29 Energy recovery or energy-saving techniques for the main processes .............................................. 29 Energy data and energy-saving techniques for other processes......................................................... 29 Best available techniques (BAT) ....................................................................................................... 29 General BAT...................................................................................................................................... 30 Process-specific BAT ........................................................................................................................ 30 Specific aspects for energy savings and energy-recovery measures .................................................. 30

9 SUMMARY OF ENERGY ISSUES IN THE BREFS .................................................................. 31 GLOSSARY.............................................................................................................................................. 33 REFERENCES......................................................................................................................................... 35

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1 THE CEMENT, LIME AND MAGNESIUM OXIDE MANUFACTURING INDUSTRIES BREF (CLM)

The importance of energy efficiency The cement industry is an energy-intensive industry with energy typically accounting for about 40 % of production costs (excluding capital costs but including electricity costs). The use of fuels and electricity are the two main types of energy used in cement manufacturing. Various conventional fossil and waste fuels can be used to provide for the thermal energy demand required for the process. In 2006, the most commonly used fuels were petroleum coke (pet coke), coal and different types of waste, followed by lignite and other solid fuels, fuel oil, and natural gas. The lime industry is also a highly energy-intensive industry with energy accounting for up to 60 % of total production costs. Kilns are fired with gaseous fuels (e.g. natural gas and coke oven gas), solid fuels (e.g. coal and coke/anthracite) and liquid fuels (e.g. heavy/light fuel oil). Furthermore, different types of wastes are used as fuels (e.g. oil, plastics, paper, animal meal and sawdust). The manufacturing of magnesium oxide is also energy intensive as magnesium oxide, and particularly DBM, is manufactured at very high temperatures. In 2008, natural gas, petroleum coke and fuel oil were used as fuels. The key environmental issues associated with cement, lime and magnesium oxide production are air pollution and the use of energy.

Main processes/technologies related to energy efficiency (burning processes) Cement For the cement industry, the clinker burning process is the main source of emissions and also the main source of energy use. The primary use of this energy is fuel for the kiln. The theoretical thermal (fuel) energy demand for cement clinker production is determined by the energy required for the chemical/mineralogical reactions of the clinker burning process (1700 to 1800 MJ/tonne of clinker) and the thermal energy required for raw material drying and preheating mainly depends on the moisture content of the raw material.The actual thermal (fuel) energy use for different kiln systems and kiln sizes is about 3000 to 6500 MJ/tonne clinker. [CLM BREF, EC, 2009, p. 47] The major users of electricity are the mills (finish grinding and raw grinding) and the exhaust fans (from the kiln/raw mill and the cement mill), which together account for more than 80 % of electrical energy usage. On average, energy costs – in the form of fuel and electricity – represent 40 % of the total production cost involved in producing a tonne of cement, as stated above. Electrical energy represents approximately up to 20 % of this overall energy requirement. The electricity demand ranges from 90 to 150 kWh/tonne of cement. Between 2004 and 2006, electricity costs increased from 14 % of total cement production cost to 25 %. The wet process is more energy intensive than the semi-wet or the dry process. [CLM BREF, EC, 2009, p. 49] To cover the necessary energy demand, waste fuels as well as conventional fuels are used and the consumption of waste fuels has consistently increased over the last few years. In 2004 in Europe, 6.1 million tonnes of different types of wastes were used as fuels in cement kilns. Of these wastes, about one million tonnes were hazardous. EU countries which are members of the European Cement Association (CEMBUREAU) are substituting traditional fuels for waste fuels increasingly, rising from 3 % in 1990 to about 17 % in 2007, equivalent to saving about 4 million tonnes of coal. It should be noted that of these wastes, the calorific values vary widely, from 3 to 40 MJ/kg. [CLM BREF, EC, 2009, p. 49]

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Lime For the lime industry, the burning process is the main source of emissions and constitutes the principal use of energy. Energy use for a given kiln type also depends on several different factors, such as the quality of the stone used, the degree of conversion of calcium carbonate to calcium oxide, the size of the stone, the moisture, the fuel, the design of the kiln, the control of the process, the air tightness, etc. The heat of dissociation of calcium limestone is 3200 MJ/tonne (about 9 % less than dolomite). The net heat use per tonne of quicklime varies by kiln design. Rotary kilns generally require more heat than shaft kilns. The heat use tends to increase as the degree of burning increases. [CLM BREF, EC, 2009, p. 242] The use of electricity varies from a low range of 5 to 15 kWh/tonne of lime for mixed-feed shaft kilns, to 20 to 40 kWh/tonne for the more advanced designs of shaft kiln and for rotary kilns. [CLM BREF, EC, 2009, p. 242] Typical heat and electrical power used by various types of lime and dolime kilns are shown in Table 1.1. The heat consumption represents about 95 % of the total energy consumption to produce lime.

Energy type used for lime and dolime manufacture Kiln type Heat use/consumption 1)

GJ/tonne Kiln electricity use

kWh/tonne Long rotary kilns (LRK) 6.0 – 9.2 18 – 25 Rotary kilns with preheater (PRK) 5.1 – 7.8 17 – 45 Parallel flow regenerative kilns (PFRK) 3.2 – 4.2 20 – 40

Annular shaft kilns (ASK) 3.3 – 4.9 18 – 352)

Up to 503)

Mixed-feed shaft kilns (MFSK) 3.4 – 4.7 5 – 15 Other kilns (OK) 3.5 – 7.0 20 – 40 1) Heat use/consumption represents about 80 % of the total energy consumption to produce lime. 2) For limestone grain sizes of between 40 and 150 mm. 3) For limestone grain sizes of <40 mm.

Table 1.1: Typical heat and electrical power used by kiln types in the EU-27 for lime and dolime manufacturing

In the special case of dead burned dolime, the energy consumption is in the range of 6.5 to 13 GJ/tonne depending on the type of kiln. Magnesium oxide The manufacturing of magnesia (dry process) is energy intensive as it is manufactured using very high temperatures. Natural gas, petroleum coke and fuel oil are used for the firing process. The energy demand for magnesia production ranges between 6 and 12 GJ/tonne MgO and is determined by different factors, such as the characteristics and moisture content (wet or very dry) of raw magnesite. [CLM BREF, EC, 2009, p. 350]

Electrical energy is used for mechanical machinery, e.g. for the ventilation system, the briquetting process and for pumps. Electricity is usually purchased from electricity providers (national grid). Electricity requirements can vary depending on the machinery in use and is typically in the range of between 75 and 180 kWh/tonne (270 to 648 MJ/tonne) of sintered magnesia. The values are similar for the production of caustic magnesia. [CLM BREF, EC, 2009, p. 350] Significantly more electrical energy (electric arc furnaces) in the range of 3500 to 4500 kWh/tonne is required for the production of fused magnesia. However, for the production of very pure grade magnesia, the value for the energy requirement can be doubled or can even be greater. [CLM BREF, EC, 2009, p. 350]

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Energy recovery or energy-saving techniques for the main processes (burning processes) Cement Thermal energy use can be reduced by considering and implementing different measures/techniques, such as implementing thermal energy optimisation in the kiln system. Several factors affect the energy consumption of modern cement kilns, such as raw material properties, e.g. moisture content, burnability, the use of fuels with different properties and varying parameters as well as the use of a gas bypass system. The measures/techniques to optimise all of these factors can be applied individually or in combination. However all measures/techniques should be considered in context with one another. Kiln systems with multistage cyclone preheaters (four to six stages) with an integral calciner and tertiary air duct are considered BAT for new plants and major upgrades. In cases where raw material has a high moisture content, three-stage cyclone plants are used. Under optimised circumstances, such a configuration will use 2900 to 3300 MJ/tonne clinker. Several thermal energy optimisation measures/techniques can be implemented at the different units of the plant. [CLM BREF, EC, 2009, p. 96] Cogeneration plants for steam and electricity or of combined heat and power plants can, in principle, be applied in cement manufacturing. This is due to the simultaneous demand of heat and electric power which has for a long time been pursued. The organic rankine cycle (ORC) process and conventional steam cycle processes are in operation. Electrical energy use can be minimised through the installation of power management systems and the utilisation of energy-efficient equipment such as high-pressure grinding rolls for clinker comminution and variable speed drives for fans as well as, in some cases, replacing old raw material mills with new mills. By using improved monitoring systems and reducing air leaks into the system, the use of electricity can also be optimised. Lime An energy management system (EMS) for monitoring the energy use of kilns is applicable in the lime industry. If only the energy efficiency and the CO2 emissions are considered, the vertical kilns in general and the parallel flow regenerative kilns (PFRK) in particular are the most efficient kilns. However, even if energy and CO2 considerations play a fundamental role, the other specifications should be considered before making a decision on the choice of kiln. In most cases, new kilns replace old kilns, but some existing kilns are modified to reduce fuel energy use. Such modifications range from minor modifications to major changes in the configuration of the kiln, depending on the technical feasibility, cost and actual need. Examples of such modifications include: • the installation of heat exchangers for long rotary kilns to recover surplus heat from flue-

gases or to permit the use of a wider range of fuels • the use of surplus heat from rotary kilns to dry limestone for other processes such as

limestone milling • in some cases, where shaft kilns have ceased to be economically viable, the conversion of

shaft kilns into modern designs, for example by converting a simple shaft kiln into the annular shaft design or by linking a pair of shaft kilns to create a PFRK. Conversion extends the life of expensive items of equipment, such as the kiln structure, the stone feed system and the lime handling/storage plant

• in exceptional cases, the shortening of long rotary kilns and the fitting of a preheater, thus reducing fuel use making it more economically efficient

• utilisation of energy-efficient equipment to minimise electrical energy usage.

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Table 1.2 lists the options for energy-efficiency improvement in lime kilns by kiln system components.

Kiln system component Description LRK PRK PFRK ASK MFSK,

OK

Combustion system

Highly efficient and flexible burner technique to adapt the temperature profile to the product requirement

X X - - -

Combustion system

Online combustion monitoring and excess air reduction X X - - -

Combustion system Combustion control through flue-gas analysis - - X X X

Combustion system

Highly flexible combustion system including possible fuel blends with waste fuels X X X X X

Cooler Efficient cooler with homogeneous air distribution and product discharge to minimise the quantity of cooling air required

X X X X X

Cooler Reliable cooler level measurement device X X - - - Flue-gas circuit Heat-recovery system X - - - -

Input control Regular fuel and stone sampling and analysis as well as adaptation of the process accordingly X X X X X

Input control Stone re-screen before kiln feed to control stone gradation X X X X X

Input control Reliable weighing/metering devices to control fuel, stone and air flowrate X X X X X

Kiln design1) Optimised length: diameter ratio X X X X X

Kiln itself Refractory internals inside the rotating part to promote heat exchange and to minimise product segregation

X X - - -

Kiln itself Efficient insulated lining to minimise the heat losses from the shell X X X X X

Kiln itself Air leakage reduction by installing seals at the kiln hood and kiln feed X X - - -

Kiln itself Channel cleaning on a regular basis - - X X X Kiln and preheater Air leakage reduction to control excess air - - X X X

Kiln operation Automatic control loops for the hood draft, excess air, fuel rate, tonne/kiln revolution, adjustment, etc. X X - - -

Kiln operation PLC and supervision system with key parameter trends X X X X X

Kiln operation Uniform operating conditions X X X X X Kiln operation Analysis of shutdown causes and repairs X X X X X Preheater Optimise pressure drop versus heat exchange - X - - - Quality follow-up

Regular lime sampling and analysis as well as kiln adjustment X X X X X

1) Only applicable to new kilns.

Table 1.2: Options for energy efficiency improvement in lime kilns

Magnesium Oxide An improved design of kilns, the optimisation of the process and the highest level of recovery and re-use of excess heat from kilns and coolers can reduce the consumption of energy and fuels. In addition, the use of oxygen (oxygen-enriched combustion air) for the firing process can increase the efficiency of the firing process thus significantly improving the effectiveness of the kiln. This is coupled with a reduction in the air requirement and thus a reduction of the N2ballast in the kiln. The energy requirement can sustainably be reduced by this means. Heat recovery from exhaust gases by the preliminary heating of the magnesite is used in order to minimise fuel energy use. Heat losses achieved from the kiln can be used for drying fuels, raw materials and some packaging materials. Electrical energy use is minimised by the utilisation of electricity-based equipment with a high energy efficiency.

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Energy data and energy-saving techniques for other processes (lime hydrating and lime grinding) There are two more processes in the lime industry worth mentioning because they are not irrelevant to energy consumption: lime hydrating and lime grinding. For lime hydrating, the energy requirements to operate the hydrators, air classifiers and conveying equipment amount to approximately 5 to 30 kWh/tonne of quicklime. The energy use for lime grinding varies from 4 to 10 kWh/tonne of quicklime for the coarser grades to 10 to 40 kWh/tonne of quicklime for the finer grades. The amount of energy required also depends on the equipment used.

Best available techniques (BAT) For the cement industry [CLM BREF, EC, 2009, p. 173] • For new plants and major upgrades, BAT is to apply a dry process kiln with multistage

preheating and precalcination. Under regular and optimised operational conditions, the associated BAT heat balance value is 2900 – 3300 MJ/tonne of clinker.

• BAT is to reduce/minimise thermal energy consumption by applying a combination of the

following measures/techniques:

a. use of improved and optimised kiln systems and a smooth and stable kiln process, operating close to the process parameter set points, which can be achieved by:

i) process control optimisation, including computer-based automatic control

systems ii) modern, gravimetric solid-fuel feed systems iii) preheating and precalcination, to the extent possible, considering the existing

kiln system configuration

b. recovering excess heat from kilns, especially from their cooling zone. In particular, the kiln excess heat from the cooling zone (hot air) or from the preheater can be used for drying raw materials

c. use of the appropriate number of cyclone stages related to the characteristics and

properties of the raw materials and fuels used

d. use of fuels with characteristics which have a positive influence on the thermal energy consumption

e. use of optimised and suitable cement kiln systems for burning wastes when

replacing conventional fuels by waste fuels

f. minimising bypass flows. • BAT is to reduce primary energy consumption by considering the reduction of the clinker

content of cement and cement products. • BAT is to reduce primary energy consumption by considering cogeneration/combined

heat and power plants if possible, on the basis of useful heat demand, within energy regulatory schemes, where economically viable.

In this context, see the Reference Document on Best Available Techniques for Energy Efficiency [ENE BREF, EC 2000].

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• BAT is to minimise electrical energy consumption by applying the following measures/techniques individually or in combination:

a. use of power management systems b. use of grinding equipment and other electricity-based equipment with high energy

efficiency. For the lime industry [CLM BREF, EC, 2009, p. 315] • BAT is to reduce/minimise thermal energy consumption by applying a combination of the

following measures/techniques:

a. use of improved and optimised kiln systems and a smooth and stable kiln process, operating close to the process parameter set points, bwhich can be achieved by:

i) process control optimisation ii) heat recovery from exhaust gases, if applicable iii) modern, gravimetric solid-fuel feed systems

b. use of fuels with characteristics which have a positive influence on thermal energy

consumption. When replacing fossil fuels by waste fuels, lime kilns and burners should be suitable and optimised for burning wastes.

c. use of excess air. Thermal energy consumption levels associated with BAT are given in Table 1.3:

Kiln type Thermal energy consumption1)

GJ/tonne Long rotary kilns (LRK) 6.0 – 9.2 Rotary kilns with preheater (PRK) 5.1 – 7.8 Parallel flow regenerative kilns (PFRK) 3.2 – 4.2 Annular shaft kilns (ASK) 3.3 – 4.9 Mixed-feed shaft kilns (MFSK) 3.4 – 4.7 Other kilns (OK) 3.5 – 7.0 1) Energy consumption depends on the type of product, the product quality, the process conditions and the raw materials.

Table 1.3: Energy consumption levels associated with BAT for thermal energy in the lime and dolime industry

• BAT is to minimise electrical energy consumption by applying the following measures/techniques individually or in combination:

a. use of power management systems b. use of optimised grain size of limestone c. use of grinding equipment and other electricity-based equipment with high energy

efficiency. For the magnesia industry [CLM BREF, EC, 2009, p. 374] • BAT is to reduce thermal energy consumption depending on the process and the products

to 6 to 12 GJ/tonnes by applying a combination of the following measures/techniques:

a. use of improved and optimised kiln systems and a smooth and stable kiln process by means of:

i) process control optimisation ii) heat recovery from exhaust gases from kiln and coolers

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b. use of fuels with characteristics which have a positive influence on thermal energy consumption

c. limiting excess air. • BAT is to minimise electrical energy consumption by applying the following

measures/techniques individually or in combination:

i) use of power management systems ii) use of grinding equipment and other electricity-based equipment with high

energy efficiency. Specific aspects for energy savings and energy recovery measures There were no specific aspects concerning savings or recovery measures mentioned. Recommendations for future studies For the cement industry • Collect information and data regarding options for minimising energy consumption or for

increasing energy efficiency • Collect data on energy consumption along with best performance data related to kiln

types used. For the lime industry • Collect information on energy consumption along with best performance data related to

kiln types and different types of products. For the magnesium oxide industry • Collect information on energy consumption for different kiln types along with specific

products and best performance data.

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2 PRODUCTION OF IRON AND STEEL BREF (I&S) The importance of energy efficiency The iron and steel industry is a highly material-intensive and energy-intensive industry. Additionally, emissions to air and solid waste and by-products belong to the main environmental issues. Main processes/technologies related to energy efficiency In this BREF, the principal ways of steelmaking are presented, namely in integrated steelworks and in electric arc furnaces. Because of the complexity of integrated steelworks, the main production steps (sinter plants, pelletisation plants, coke oven plants, blast furnaces and basic oxygen steelmaking, incl. casting) are described separately. Therefore, all these production steps should be considered important as regards energy efficiency. However, the most energy-consuming process unit in iron and steel production is the blast furnace. For a blast furnace using coal injection and top gas pressure recovery for electricity generation, the total energy input amounts to 18.67 GJ/tonne pig iron (made up of coke = 12.4, powdered coal = 1.63, hot blast = 4.52 and electricity = 0.12) [I&S BREF, EC 2000, p. 191]. The range of energy use within the sinter plants is about 1 125 to 1 920 MJ/tonne sinter (thermal energy) with an average consumption of 1480 MJ/tonne sinter. Coke is the dominant sinter plant energy input (about 85 %), with electricity and gas supplying the remainder in equal amounts [I&S BREF, EC 2000, p. 44]. In pelletisation plants, energy consumption differs depending on the type of plant. If the pelletisation plant is part of an integrated steelworks, the following energy consumptions are possible: coke oven gas (COG) 398.7 MJ/tonne, natural gas 209 MJ/tonne, coke 283 MJ/tonne. With standalone pelletisation plants, energy consumption is less: coal 213 to 269 MJ/tonne, oil 38 to 171 MJ/tonne [I&S BREF, EC 2000, p. 95]. Electricity varies from 51 to 128 MJ/tonne independent of the type of plant. In coke oven plants, energy consumption can be 3200 to 3900 MJ/tonne blast furnace gas + COG and 20 to 170 MJ/tonne electricity. An energy balance for a coke oven plant (without COG treatment) shows that with an input of 43 GJ/tonne coke, the energy loss will amount to 3.33 GJ/tonne (<10 %) [I&S BREF, EC 2000, p. 122, 127–128]. In the basic oxygen furnace (BOF), fuel is consumed to preheat and dry the converters after relining and repair. This thermal energy consumption is approximately 0.051 GJ/tonne liquid steel (LS). Electricity consumption is estimated to be 23 kWh/tonne LS or 0.08GJ/tonne LS [I&S BREF, EC 2000, p. 242]. Electric steelmaking is usually performed in an electric arc furnace (EAF). This furnace plays an important and increasing role in modern steel works in the European Union (35.3 % of the overall steel production). The total energy consumption amounts to 2 300 to 2 700 MJ/tonne [I&S BREF, EC 2000, p. 281].

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Energy recovery or energy-saving techniques for the main processes For blast furnaces, the following process-integrated measures belong to energy recovery or energy-saving techniques [I&S BREF, EC 2000, p. 194–198]: • direct injection of reducing agents. Energy savings can amount to 0.68 GJ/tonne pig iron

or 3.6 % of the gross energy consumption of the blast furnace • energy recovery from blast furnace gas. Approximately 5 GJ/tonne pig iron or 30 % of

the gross energy consumption of the blast furnace • energy recovery from top gas pressure. Energy savings are estimated to be up to 0.4

GJ/tonne pig iron for a 15 MW turbine, which correspond to 2 % of the gross energy consumption of the blast furnace

• energy savings at the hot stove. About 0.5 GJ/tonne pig iron energy savings is possible. Within sinter plants, the following technique can be considered as an energy recovery technique: • heat recovery from sintering and sinter cooling [I&S BREF, EC 2000, p. 53–54] where

the recovered heat amounts to 30 % of the input heat. Two kinds of potentially re-usable waste energy are discharged from the sinter plants: the sensible heat from the main exhaust gas from the sintering machines, and the sensible heat of the cooling air from the sinter cooler. The amount of waste heat recovered can be influenced by the design of the sinter plant and the heat-recovery system:

◦ sinter cooler waste heat recovery with conventional as well as EOS sintering ◦ (energy recovery = 18 % of the total energy input for the waste heat boiler) ◦ sinter cooler and waste gas heat recovery with sectional waste gas recirculation ◦ (energy recovery = 23.1 % of the total energy input) ◦ strand cooling and waste heat recovery with partial waste gas recirculation.

The following technique can be considered as an energy recovery technique in pelletisation plants [I&S BREF, EC 2000, p. 99]: • the recovery of sensible heat from the induration strand. Approximately 67.5 MJ/tonne

pellet or 4 % of gross energy consumption. There are no energy-saving techniques mentioned for coke oven plants. For the basic oxygen steelmaking process the following technique should be considered as regards energy recovery and savings [I&S BREF, EC 2000, p. 244-246]: • energy recovery from the BOF gas. When the energy from the BOF gas is recovered

(waste heat recovery and/or BOF gas recovery), the BOF becomes a net producer of energy. In a modern plant, energy recovery can be as high as 0.7 GJ/tonne LS.

In the electric steelmaking industry, several energy recovery and energy-saving techniques are available [I&S BREF, EC 2000, p. 295–301]. The most important are: • EAF process optimisation • scrap preheating.

Energy data and energy-saving techniques for other processes Because of the complexity of integrated steelworks and the structure of the Iron and Steel BREF, all relevant processes are discussed together with the most important one (blast furnaces) in the preceding sections for this sector.

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Best available techniques (BAT) Principally there are two different types of techniques: those which should be considered in the determination of BAT (techniques not yet considered BAT), and others which are already considered as BAT. In the iron and steel production industry, these techniques are almost the same. All the techniques described above can be considered in the determination of BAT. The following list summarises the BAT concerning energy: • process-specific BAT for blast furnaces including:

◦ blast furnace gas recovery ◦ direct injection of reducing agents ◦ energy recovery of top blast furnaces gas pressure where prerequisites are present ◦ hot stoves (where design permits).

• process-specific BAT for sinter plants which includes the recovery of sensible heat • process-specific BAT for pelletisation plants which includes the recovery of sensible heat • process-specific BAT for basic oxygen steel making and casting which includes BOF gas

recovery and primary dedusting. • process-specific BAT for electric steelmaking and casting which includes scrap

preheating in order to recover sensible heat from primary off-gas.

Specific aspects for energy savings and recovery measures The information concerning energy recovery or energy-saving techniques is well presented and well structured.

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3 NON-FERROUS METALS INDUSTRY BREF (NFM) The importance of energy efficiency Energy consumption and the recovery of heat and energy are important factors in the production of non-ferrous metals. They depend on the efficient use of the energy content of sulphidic ores, the energy demand of the process stages, the type and supply method of energy used and the use of effective methods of heat recovery. There has been a steady improvement in the environmental performance and energy efficiency of the industry since 1985. The recycling performance of the industry is unmatched by any other industry. Main processes/technologies related to energy efficiency The most important processes and techniques within the non-ferrous metals industries related to energy efficiency are pyrometallurgical processes. They are highly heat intensive and the process gases contain a lot of energy. Energy recovery or energy saving techniques for the main processes There are a lot of energy-saving techniques described for the pyrometallurgical processes. A few examples are listed below: • use of steam to produce electricity and/or for heating requirements • use of the excess heat to melt secondary materials without the use of additional fuel • use of oxygen-enriched air or oxygen in the burners to reduce energy consumption by

allowing autogenic smelting or the complete combustion of carbonaceous material • separate drying of concentrates at low temperatures which reduces the energy

requirements • heat recovery by using hot gases from melting stages to preheat the furnace charge. The

recovered heat is approximately 4 – 6 % of the furnace fuel consumption • collecting and burning carbon monoxide (produced in electric or blast furnaces) as a fuel

for several different processes or to produce steam or other energy • recirculation of contaminated waste gas back through an oxy-fuel burner which has

resulted in significant energy savings • use the heat content of process gases or steam to raise the temperature of leaching liquors. Energy data and energy-saving techniques for other processes There is a lot of information concerning energy consumption for the production of different non-ferrous metals. Basically these metals are divided into ten groups and are described in Table 3.1.

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Non-ferrous metal Description of energy consumption

Copper

The energy use of the electrolytic process is most significant. The production energy (net) requirement for a number of processes using copper concentrate is in the range 14 – 20 GJ/tonne copper cathode. The energy consumed by the electro-refining stage of copper production is reported to be 300 to 400 kWh/tonnes of copper1

Aluminium The main cost of producing primary aluminium is electricity (about 30 % of the production costs). A typical range for energy consumption is 8 to 13.5 GJ/tonnes aluminium2

Lead and zinc The energy consumption for the different lead and zinc processes varies to a large extent. Electricity is used for most of the processes3

Ferro-alloys

The ferro-alloys industry is a major consumer of energy. The laws of thermodynamics limit the reduction of energy necessary for the smelting process. The reduction of the overall energy consumption is therefore in most cases only possible by using an efficient energy recovery system4

Nickel

The energy used for the production of matte from sulphidic ores is reported to be in the range 25 to 65 GJ/tonnes of nickel for ores containing 4 to 15 % Ni. The energy used in the various refining stages is reported to be 17 to 20 GJ/tonnes of Ni5

1) [NFM BREF, EC 2000, p. 214] 2) [NFM BREF, EC 2000, p. 283–284] 3) [NFM BREF, EC 2000, p. 359] 4) [NFM BREF, EC 2000, p. 528–532] 5) [NFM BREF, EC 2000, p. 631]

Table 3.1: Energy consumption for the processing of several ferrous metals.

Ferro-alloy production is a high energy-consuming process because high temperatures are needed for the reduction of metal oxides and for smelting. In the Non-ferrous Metals BREF several different measures for energy recovery and the use of the recovered energy are listed [NFM BREF, EC 2000, p. 546–548].

Best available techniques (BAT) Principally, there are two different types of techniques: those which have to be considered in the determination of BAT (techniques not yet considered BAT), and others which are already considered as BAT. For the non-ferrous metals industry, the BAT conclusions for energy recovery are: • the production of steam and electricity from the heat generated in waste heat boilers • the use of the heat of reaction to smelt or roast concentrates or melt scrap metals in a

converter • the use of hot process gases to dry feed materials • the preheating of a furnace charge using the energy content of furnace gases or hot gases

from another source • the use of recuperative burners or the preheating of combustion air • the use of the CO produced as a fuel gas • the heating of leach liquors from hot process gases or liquors • the use of plastic contents in some raw materials as a fuel, provided that good quality

plastic cannot be recovered and VOCs and dioxins are not emitted • the use of low-mass refractories where practicable.

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Specific aspects for energy saving and energy recovery measures Most of the energy recovery or energy-saving methods are site specific. Therefore, not every technique can be implemented. The techniques especially to recover heat vary from site to site. A number of factors are involved here, such as the potential uses for heat and energy on or near the site, the scale of operation, and the potential for gases or their constituents to foul or coat heat exchangers. Recommendations for future studies Additional efforts should be made to establish a basis of information including specific emissions and consumptions data. Energy usage should also be reported on this basis.

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4 PULP AND PAPER INDUSTRY BREF (PP) The importance of energy efficiency The manufacturing of pulp and paper requires a large amount of process water and energy in the form of steam and electric power. Consequently, the main environmental issues associated with pulp and paper production are discharges to water, emissions to air and energy consumption. Main processes/technologies related to energy efficiency There are several different pulping and papermaking processes. Depending on the type of plant, a paper mill can be integrated with the pulping operations on the same site or it can produce paper in stand-alone plants using purchased pulp. The PP BREF is divided into five main chapters describing the different processes, whereas energy aspects are discussed for each process separately. Evaporation and the maintenance of paper machines are the most important and most energy-consuming processes. The kraft (sulphate) pulping process Within this pulping process the major part of the heat energy is consumed for heating different fluids and for evaporating water. Electrical energy is mostly consumed by the transportation of materials (pumping) and by the operation of the paper machine. The manufacturing of bleached kraft pulp consumes about 10 to 14 GJ/Adt of heat energy (steam for the production of electrical power not included). The consumption of electrical energy is 600 to 800 kWh/Adt, including the drying of pulp. The energy consumption for pulp drying is about 25 % of the heat energy and 15 – 20 % of the electrical energy. Over 50 % of the electrical energy consumption is used for pumping [PP BREF, EC 2000, p. 52–56]. The sulphite pulping process A chapter for energy demand was forseen, but no data were made available [PP BREF, EC 2000, p. 132]. The mechanical and chemi-mechanical pulping process Energy consumption depends on the particular pulping process. For groundwood, for instance, the required energy varies between 1100 to 2300 kWh/tonne of pulp, while for refiner mechanical pulps the energy requirement amounts to 1 600 to 3000 kWh/tonne of pulp. Finally, the thermo-mechanical pulps consume about 1000 to 4300 kWh/tonne of pulp [PP BREF, EC 2000, p. 182–185]. Recovered paper processing Paper and board mills require substantial amounts of steam for heating water and large quantities of electricity for driving the machinery, and for pumping, vacuum, ventilation and waste water treatment. In paper mills, energy is usually the main factor in the operating costs. For example, in the Netherlands for recovered paper processing an average specific electricity consumption of 322 kWh/tonne (disregarding the difference in specific electricity consumption between recycled fiber processing (RCF) with and without de-inking) have been reported [PP BREF, EC 2000, p. 241–245]. Papermaking and related processes The paper industry could be generally described as energy intensive. Energy is the third highest cost in the papermaking process, accounting for approximately 8 % of turnover. The total demand for energy (consumption) in the form of heat (steam) and electric power for a non-integrated fine paper mill has been reported as: • process heat: 8 GJ/tonne (about 2 222 kWh/tonne) • electric power: 674 kWh/tonne. More detailed information about the energy consumption of each single production step can be found in the PP BREF, p. 336–342.

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Energy recovery or energy-saving techniques for the main processes The energy recovery and energy-saving techniques for the main processes are discussed below and can be considered as BAT. Energy data and energy saving techniques for other processes Most of the techniques to save energy are described below and can be considered as BAT. There is some information on the processes described below. Sulphite pulping During the recovery process of chemicals, substantial amounts of energy can be produced (in recovery boilers) for steam and for power generation of the pulp mill. Mechanical and chemi-mechanical pulping Depending on the particular pulping process, it is possible to recover 20 – 30 % of energy either as steam or as hot water. For thermo-mechanical pulps, the recoverable energy as steam can even reach 40 to 45 %. [PP BREF, EC 2000, p. 183]. Best available techniques (BAT) Principally there are two different types of techniques: those which should be considered in the determination of BAT (techniques not yet considered BAT), and others which are already considered as BAT, resulting from the BAT conclusions. Furthermore, the BAT are subdivided into general BAT concerning general aspects and measures and into process-specific BAT regarding specific information. General BAT The following measures can be considered general techniques (primary measures) for all processes [PP BREF, EC 2000, p. 100]: • training, education and motivation of staff and operators • process control optimisation • sufficient maintenance of the technical units • an environmental management system which optimises management, increases awareness

and includes goals and measures, and process and job instructions, among other things. Process-specific BAT for the kraft pulp and sulphite pulp mills Process-specific measures for high-heat recovery and low-heat consumption [PP BREF, EC 2000, p. 110–111] include: • high content of dry solids in the form of black liquor and bark • high efficiency of the steam boiler, e.g. low flue-gas temperature • an effective secondary heating system, e.g. hot water at about 85 ºC • a well closed-up water system • a relatively well closed-up bleaching plant • high pulp concentration (medium consistency (MC) technique) • pre-drying of lime • use of secondary heat to heat buildings • good process control. Process-specific measures for low consumption of electric power include: • maintaining as high a pulp consistency as possible in screening and cleaning • controlling the speed of various large motors • running efficient vacuum pumps • proper sizing of pipes, pumps and fans.

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Process-specific measures for a high generation of electric power include: • high boiler pressure • outlet steam pressure in the back-pressure turbine as low as is technically feasible • condensing turbine for power production from excess steam • high turbine efficiency • preheating of air and fuel charged to boilers. Process-specific BAT for the mechanical and chemi-mechanical pulp and paper mills The following process-specific measures pertain to mechanical and chemi-mechanical mills: • the implementation of a system for monitoring energy use and performance • upgrading equipment • minimisation of reject losses by using efficient reject handling stages and reject refining • use of effective heat-recovery systems • application of cogeneration of heat and power where the power to steam ratio allows for

it. Process-specific BAT for recovered paper processing paper mills The following process-specific measures pertain to recovered paper processing mills: • implementation of a system for monitoring energy use and performance • upgrading equipment • application of anaerobic waste water treatment. Process-specific BAT for paper mills The following process-specific measures pertain to paper mills: • implementation of a system for monitoring energy use and performance • more effective dewatering of the paper web in the press section of the paper machine by

using wide-nip pressing technologies • use of energy-efficient technologies, such as high-consistency slushing, best practice

refining, twin wire forming, optimised vacuum systems, speed-adjustable drives for fans and pumps, high-efficiency electric motors, sizing electric motors properly, steam condensate recovery, increasing size press solids or exhaust air heat recovery systems

• reduction of direct use of steam by careful process integration by using pinch analysis. BAT associated consumption values Energy-efficient kraft pulp and paper mills consume heat and power as follows [PP BREF, EC 2000, p. 110 – 111]: • non-integrated bleached kraft pulp mills: 10 to 14 GJ/Adt of process heat and

0.6 to 0.8 MWh/Adt of power • integrated bleached kraft pulp and paper mills: 14 to 20 GJ/Adt of process heat and

1.2 to 1.5 MWh/Adt of power • integrated unbleached kraft pulp and paper mills: 14 to 17.5 GJ/Adt of process heat and

1 to 1.3 MWh/Adt power.

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Energy consumption associated with BAT for sulphite pulp and paper mills consume heat and power as follows: • non-integrated bleached sulphite pulp mills: 16 to 18 GJ/Adt of process heat and

0.7 to 0.8 MWh/Adt of power • integrated bleached sulphite pulp and coated fine paper mills: 17 to 23 GJ/Adt of process

heat and 1.5 to 1.75 MWh/Adt of power • integrated bleached sulphite pulp and uncoated paper mills: 18 to 24 GJ/Adt of process

heat and 1.2 to 1.5 MWh/Adt of power. Energy-efficient mechanical pulp and paper mills consume heat and power as follows [PP BREF, EC 2000, p. 214–215]: • non-integrated CTMP: 2 to 3 MWh/Adt of power • integrated newsprint mills: 0 to 3 GJ/Adt of process heat and 2 to 3 MWh/Adt of

electricity • integrated LWC paper mills: 3 to 12 GJ/Adt of process heat and 1.7 to 2.6 MWh/Adt of

power • integrated SC paper mills: 1 to 6 GJ/Adt of process heat and 1.9 to 2.6 MWh/Adt. Energy-efficient recovered paper mills consume heat and power as follows [PP BREF, EC 2000, p. 302–303]: • integrated non-deinked RCF paper mills: 6 to 6.5 GJ/Adt of process heat and

0.7 to 0.8 MWh/Adt of power • integrated tissue mills with DIP plants: 7 to 12 GJ/Adt of process heat and 1.2 to 1.4

MWh/Adt of power • integrated newsprint or printing and writing paper mills with DIP plants: 4 to 6.5 GJ/Adt

of process heat and 1 to 1.5 MWh/Adt of power. Energy efficient non-integrated paper mills consume heat and power as follows [PP BREF, EC 2000, p. 411–412]: • non-integrated uncoated fine paper mills: 7 to7.5 GJ/Adt of process heat and

0.6 to 0.7 MWh/Adt of power • non-integrated coated fine paper mills: 7 to 8 GJ/Adt of process heat and 0.7 to 0.9

MWh/Adt of power • non-integrated tissue mills based on virgin fibre: 5.5 to 7.5 GJ/Adt of process heat and

0.6 to 1.1 MWh/Adt of power. Specific aspects for energy savings and energy-recovery measures Some energy recovery and energy-saving techniques are site specific. This means that it depends on the location of the mill as to whether certain techniques can be applied or not. Recommendations for future studies Little information is available on the assessment of energy-efficient technologies and practical experiences of the results of implementation in the pulp and paper industry. When energy data and balances are reported, the assumptions and conditions are often not sufficiently qualified. More work on this important issue and the derivation of production-specific energy consumption figures are needed before the next BREF review.

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5 CHLOR-ALKALI MANUFACTURING INDUSTRY BREF (CAK) The importance of energy efficiency The chlor-alkali process needs very large amounts of electricity. It is one of the largest consumers of electrical energy. Main processes/technologies related to energy efficiency In the European Union, the chlor-alkali process was mainly used in mercury (amalgam) cell technology. Past mercury contamination of land and waterways from mercury plants is a major environmental problem at some sites. For many years, the mercury cell has been a significant source of environmental pollution, since some mercury is lost from the process to air and water and shows up in products and waste. Amalgam technology needs 3560 ACkWh/tonne Cl2 (alternating current kilowatt hours/tonne of chlorine) assuming 50 % of caustic soda and before liquefaction of chlorine. The operation of a chlor-alkali plant is dependent on the availability of large quantities of direct current (DC) electric power, which is usually obtained from a high voltage source of alternating current (AC) [CAK BREF, EC 2000, p. 36–37]. Energy recovery or energy-saving techniques for the main processes/technologies There is little information about energy recovery or energy-saving techniques within mercury cell technology. More information is given in the section on BAT. Energy data and energy-saving techniques for other processes In the chlor-alkali industry, there are two other technologies that of lesser in importance in the sense of frequency compared to mercury cell technology, but that are more interesting as regards energy savings: asbestos diaphragm cell and membrane cell technology. The total adjusted energy consumption of diaphragm technology is almost the same as that of mercury: 3580 ACkWh/tonne Cl2. For membrane cell technology, the energy consumption amounts to 2970 ACkWh/tonne Cl2 [CAK BREF, EC 2000, p. 36–37]. Best available techniques (BAT) Principally, there are two different types of techniques: those which should be considered in the determination of BAT (techniques not yet considered BAT) and others which are already considered BAT. A best available technique for the production of chlor-alkali is membrane technology. Non-asbestos diaphragm technology is also a BAT. The total energy use associated with BAT for producing chlorine gas and 50 % caustic soda is less than 3000 ACkWh/tonne of chlorine when chlorine liquefaction is excluded, and less than 3200 ACkWh/tonne of chlorine when liquefaction is included. For mercury cell plants, the best available technique is conversion to membrane cell technology. For diaphragm cell plants, the best available technique is conversion to membrane cell technology or use of non-asbestos diaphragms. Specific aspects for energy saving and energy-recovery measures There are hardly any energy recovery or energy-saving techniques described in the BREF, because there are not many ways to save energy in mercury cell and diaphragm cell technology. The BAT is the conversion to membrane cell plants.

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The chlor-alkali production technology is site specific, because of the difficulties in the storage and the transport of chlorine. Therefore, production usually takes place near the consumers. More than 85 % of the chlorine produced in the European Union is used on the same or on adjacent sites for other chemical processes. The Chlor-Alkali Manufacturing Industry BREF also contains information about national and international legislation within the European Union. The emphasis is on air emissions and discharges to water, while energy saving aspects are mentioned incidentally [CAK BREF, EC 2000, p. Annex D, 136–137].

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6 FERROUS METALS PROCESSING INDUSTRY BREF (FMP) The importance of energy efficiency The Ferrous Metal Processing industry BREF is divided into three main parts (hot and cold forming, continuous hot dip coating lines, and batch galvanising) which describe the different specific processes, and in one part, techniques which might be applied to several subsectors are described. Energy consumption is a main environmental issue in the first two parts of the FMP BREF together with air emissions (especially NOX, SO2) and dust emissions. In the third part, energy use does not play an important role, which is probably why there is almost no information. The fourth part contains detailed technical descriptions and information on techniques which might be applied to several subsectors. Most of this information is concerned with the reduction of emissions, while energy aspects are inadequately discussed. Main processes/technologies related to energy efficiency Part A: hot and cold forming There are several techniques and processes within hot and cold forming technology, but the most important concerning energy efficiency is the heating (reheating) and heat treatment processes in furnaces. The energy consumption of the furnaces depends on several parameters such as the furnace design, the throughput and shift patterns, the designed length of the recuperation zone in the furnace, and the burner design, among other things. The energy consumption for these furnaces was between 0.7 and 6.5 GJ/tonne; with a typical range being 1 to 3 GJ/tonne [FMP BREF, EC 2000, p. 63–65]. Part B: continuous hot dip coating lines As in Part A, the most important processes are reheating and heat treatment in the furnaces. Part C: batch galvanising No special process is mentioned. Energy recovery or energy-saving techniques for the main processes Almost every energy-saving technique regarding reheating and heat treatment furnaces is considered as BAT (see the section on Process-specific BAT). Energy data and energy-saving techniques for other processes More processes and techniques concerning energy consumption in part A are: • hot rolling 72 to 140 kWh/tonne (deformation energy) • pickling of alloy 0.015 to 0.3 GJ/tonne (electrical energy) • cold rolling 0.2 to 0.3 GJ/tonne (electrical energy) • annealing of alloy 0.06 to 0.12 GJ/tonne (electrical energy) • tempering 0.02 to 0.15 GJ/tonne (electrical energy) • finishing (cutting, inspection, packing) 0.02 to 0.04 GJ/tonne (electrical energy) • and many more techniques where energy data are not available. There is limited information on energy-saving techniques [FMP BREF, EC 2000, p. 81–87].

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In Part B, several other processes are mentioned. However, there is only limited information on energy (consumption) [FMP BREF, EC 2000, p. 276, 281–282], which is listed here: • consumption for total coating line 800 to 1 300 MJ/tonne (natural gas)

44 to 140 MJ/tonne (electrical) 20 to 44 MJ/tonne (hot water)

• aluminising of sheet 7 kWh/tonne (electricity) 273 kWh/tonne (gas)

• lead-tin coating of sheet 2.43 kWh/tonne (electricity) 1490 MJ/tonne (gas).

Energy consumption data for Part C [FMP BREF, EC 2000, p. 345–346, 350] includes: • degreasing 0 – 44.6 kWh/tonne • pickling 0 – 25 kWh/tonne • hot dipping 180 – 1000 kWh/tonne • and many more techniques where energy data are not available. Additionally, for the hot dipping process there is a short description of possible energy savings [FMP BREF, EC 2000, p. 377–378, 384]. In enclosed galvanising pot, energy savings are due to reduced surface heat loss from the galvanising bath. Heat recovery from galvanising kettle heating results in reduced fuel consumption. Energy reductions in the range of 15 to 45 kWh/tonne black steel can be achieved. Best available techniques (BAT) Principally, there are two different types of techniques: those which should be considered in the determination of BAT (techniques not yet considered BAT), and others which are already considered as BAT. For the ferrous metals processing industry, these techniques are almost the same. Furthermore, it is possible to divide the BAT into general techniques (primary measures) and more process specific ones. General BAT Measures which can be considered general techniques (primary measures) for the hot and cold forming part include, for example furnace design or proper operation and maintenance: Process-specific BAT For 'Part A- hot and cold forming', BAT are related to reheating and heat treatment furnaces and include: • recovery of heat in the waste gas by feedstock preheating • recovery of heat in the waste gas by regenerative or recuperative burner systems • recovery of heat in the waste gas by means of a waste heat boiler or evaporative skid

cooling (where there is a need for steam) leads to energy savings between 25 to 50 % • limiting the air preheating temperature. BAT related to 'descaling' includes: • material tracking to reduce water and energy consumption. For Parts B and C, there are no BAT regarding energy aspects. Most of the energy-saving techniques are mentioned above.

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Specific aspects for energy savings and energy-recovery measures For some techniques (also BAT), there is a trade-off between energy savings and NOXemissions. Reductions in SO2, CO2 and CO should be weighted against the disadvantage of potentially increased emissions of NOX.

Recommendations for future studies For the revision of the FMP BREF, information on emissions, consumption levels and economics should be provided. For quite a number of the techniques to be considered in the determination of BAT, there is a lack of information on these aspects at the moment. Of particular interest are figures on NOX emissions both for furnaces that use air preheating and those that do not. Such data would make it possible to do both a more thorough evaluation of the efficiency of reduction measures and a comparison of the advantages and disadvantages of energy savings versus NOX emissions.

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7 GLASS MANUFACTURING INDUSTRY BREF (GLS) The importance of energy efficiency Glassmaking is a very energy-intensive activity and the choice of energy source, heating technique and heat recovery methods are central to the design of the furnace. The key environmental issues are emissions to air and energy consumption. Main processes/technologies related to energy efficiency The melting operation is the central process in the glass manufacturing industry. Its environmental performance and energy efficiency is also affected by the choice of energy source, the heating technique and the heat recovery methods. The three main energy sources for glassmaking are natural gas, fuel oil and electricity. In general, the energy necessary for melting glass accounts for over 75 % of the total energy requirement of glass manufacturing. The theoretical energy requirements for the melting processes of the three most common glass types (soda-lime, borosilicate and crystal glass) for the melting process vary from 2.25 to 2.68 GJ/tonne. The actual energy requirements in the various sectors vary widely from about 3.5 to over 40 GJ/tonne. The amount of energy needed depends very heavily on the furnace design, scale and method of operation. However, most glass is produced in large furnaces and the energy requirement for melting is generally below 8 GJ/tonne [GLS BREF, EC 2000, p. 72–75]. In 1997, the energy consumption of the glass industry was approximately 265 GJ/tonne. Energy recovery or energy-saving techniques for the main processes The main melting techniques are listed below: • use of regenerative furnaces • use of recuperative furnaces • oxy-fuel firing • use of electric furnaces • combined fossil fuel and electric melting • use of discontinuous batch melters. For the regenerative furnaces, a heat recovery-system is used, while for the oxy-fuel firing melting technique, energy savings are possible because it is not necessary to heat the atmospheric nitrogen to the temperature of the flames. Energy data and energy-saving techniques for other processes Generally, the glass making industry can be subdivided into eight sectors based on the products manufactured. These products consist of container glass, flat glass, continuous filament glass fibre, domestic glass, special glass, mineral wool, ceramic fibre and frits. For each of these subsectors, the melting process is dominant. However, there are a few other processes that should be mentioned. • forming (2 to 5 %) • annealing (about 3 %) • forehearths (about 6 %) • conversion (about 11 %) • factory heating • general services. The values show the range of the total energy consumption.

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Best available techniques (BAT) For the glass manufacturing industry, only techniques used in the determination of BAT are mentioned here. These techniques for reducing energy use are: • melting technique and furnace design (by about 15 %) • combustion control and fuel choice n.a. • cullet usage (2.5 to 3 %) • waste heat boilers n.a. • cullet/batch preheating (10 to 20 %) The values show the range of energy savings. Specific aspects for energy savings and energy-recovery measures There were no specific aspects concerning energy saving or energy-recovery measures mentioned in the BREF. Recommendations for future studies When the work is reviewed, a more in-depth assessment of techniques to improve energy efficiency would be useful, taking into account information made available recently.

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8 INDUSTRIAL COOLING SYSTEMS BREF (ICS) The importance of energy efficiency Cooling is an essential part of many industrial processes and should be seen as an important element in the overall energy management system. The intention is to re-use the superfluous heat of one process in other parts of the process or in different processes on site in order to minimise the need for the discharge of waste heat into the environment. Main processes/technologies related to energy efficiency In this industrial sector it is easier to speak about cooling systems rather than processes. Usually it is a process that should be cooled. There are eight cooling systems mentioned, whereas each system is principally characterised by the cooling medium, the main cooling principle, minimum approaches, the minimum achievable end temperature of the process medium, and the capacity of the industrial process. The environmental aspects are different for each of the industrial cooling systems. As far as energy consumption is concerned, the most important cooling system is closed circuit dry cooling. Most of the high-energy consumption is used for driving the fans. The energy requirements of industrial cooling systems can be considered direct or indirect consumption. Direct consumption is the use of energy to operate the cooling system. The major energy users are pumps and fans. The energy consumption of the production process is referred to as the indirect energy consumption caused by the cooling process. The total (direct and indirect) energy consumption for a closed circuit cooling tower amounts to more than 34 kWe/MWth [ICS BREF, EC 2000, p., 67–70]. Energy recovery or energy-saving techniques for the main processes The energy saving and energy-recovery techniques mentioned here do not refer just to the most important cooling system (closed-circuit dry cooling), but rather give an overview of all applied cooling systems [ICS BREF, EC 2000, p., executive summary, V]. Basically it is possible to reduce direct or indirect energy consumption. For indirect energy reduction, the following measures are available: • select the cooling configuration with the lowest specific indirect energy consumption (in

general, once-through systems) • apply a design with small approaches • reduce the resistance to heat exchange by proper maintenance of the cooling system. The following measures are applicable to the reduction of direct energy consumption: • use of pumps and fans with higher efficiencies • reduce resistance and pressure drops in the process through the design of the cooling

system and by the application of low-resistance drift eliminators and tower fills • proper mechanical or chemical cleaning of surfaces to maintain low resistance in the

process during operation. Energy data and energy-saving techniques for other processes All measures to reduce energy consumption have been discussed above for all cooling systems together. Best available techniques (BAT) Principally, the BAT are subdivided into general and process-specific BAT.

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General BAT The following are BAT in the design phase of a cooling system: • to reduce resistance to water and airflow • to apply high efficiency and low-energy equipment • to reduce the amount of equipment demanding energy • to apply optimised cooling water treatment in once-through systems and wet cooling

towers to keep surfaces clean and to avoid scaling, fouling and corrosion. Process-specific BAT The selection of wet or dry cooling or wet and dry cooling to meet process and site requirements should be aimed at the highest overall energy efficiency. To achieve a high overall energy efficiency when handling large amounts of low level heat (10 to 25 ºC), it is BAT to use open once-through systems for cooling. In a greenfield situation, this may justify selection of a (coastal) site with reliable and large amounts of cooling water available and with surface water with sufficient capacity to receive large amounts of discharged cooling water. When cooling hazardous substances that pose a high risk to the environment, it is BAT to apply indirect cooling systems using a secondary cooling circuit [ICS BREF, EC 2000, p., 125–126]. Specific aspects for energy savings and energy-recovery measures It is acknowledged that the final BAT solution is a site-specific solution.

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9 SUMMARY OF ENERGY ISSUES IN THE BREFS All of the analysed BREFs contain a considerable amount of information and data on energy. The most specific information is available for energy consumption within the majority of the sectors. As far as energy saving and energy-recovery techniques are concerned, there is less information. In general, there is a need for more information regarding all the energy aspects (consumption, savings and recovery measures, and values). BAT are generally subdivided into general and process-specific BAT. In a few cases, each process-specific BAT within an industrial sector is shown in a table and described separately. The purpose of the BAT chapter is thus to provide general indications regarding the emission and consumption levels that might be considered an appropriate reference point to assist in the determination of BAT based permit conditions or for the establishment of general binding rules. In other words, environmental permit conditions should be based on BAT, and BREFs (which are not binding) should be taken into consideration as an important source of information on BAT. A description of the energy aspects found in each BREF is shown in Table 9.1

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Cement andlime

March 2000

Iron and steelMarch 2000

Non-ferrous metalsMay 2000

Pulp and PaperJuly 2000

Chlor-alkaliOctober 2000

Ferrous metalsOctober 2000

GlassOctober 2000

Cooling systemsNovember 2000

Importance of EEcompared to otherenvironmental issues

Highly intensive(air emissions)

Highly intensive(air emissions)

Important(air emissions)

High(water discharges)

Important(air/water emissions)

Important(air emissions)

Very intensive(air emissions) High

Which is the mostimportant and energy-intensiveprocess/technology?

Clinker burning,lime burning.

Blast furnace Pyrometallurgicalprocesses

Depends on the plantevaporation/paper machine

Mercury (amalgam)technology

Heating and heattreatment furnace Melting

Closed-circuit drycooling dry aircooling.Yes, only forconsumption

Are energy dataavailable?

Yes, only forconsumption

Yes (gooddescription) Yes, data available Yes, only for consumption Yes (good

description)Yes (gooddescription)

Yes, only forconsumption

Are energyrecovery/savingstechniques for thisprocess mentioned?

Not in detail,partly alsoconsidered asBAT

Yes, a lot partlyalso considered asBAT

Yes, forconsumption andrecovery

Consumption andrecovery, techniques ingeneral considered as BAT

Yes, in terms of processselection

Selections, a lotpartly alreadyconsidered

Yes, a lot Yes, but rarely

Are energy data forother processes(including techniques)available?

Yes, in generalfor consumption Yes

Yes, consumptionand recovery dataavailable

Yes, consumption dataavailable

Yes, consumption dataavailable Yes (good)

Yes, dataavailable mainlyfor consumption

Yes, consumptiondata available

General BAT available Yes (primarymeasures) Yes Yes Yes Yes (primary measures) Yes Yes (design

phase) Yes (design phase)

BAT for specificprocesses Yes, limited Yes, BAT for all Yes Yes Yes, limited Yes

Not mentioned asBAT (to considerin thedetermination ofBAT)

Yes

Energy data in BATYes, onlyconsumption(limited)

Yes, table foreach BAT Yes Yes, almost in every BAT Yes, limited

Yes, data aboutconsumption,saving recovery

Not concerningEE, only emissionlevels

Yes, partly

Are energyrecovery/savingsmeasures site specific?

No Not mentioned Yes Yes, a few (CHP) Yes, because of difficulties instorage and transport Not mentioned Not mentioned Yes, but difficult to

quantify

Are anyrecommendations for thenext update mentioned?

Survey ofcurrenttechniquesconsumption isuseful.

n.aMore informationabout consumptiondata.

More information on theassessment of energyefficient techniques.

n.a.

Provide moreinformation onemission andconsumptionlevels

More techniquesfor EEimprovementwould be useful.

n.a.

Special comments

Energy costs =30 – 50 % oftotal productioncosts.Associated BATheat balancesvalue is 3000MJ/tonne clinker

There are manydifferent kinds ofplants; each hasdifferentprocesses andtechniques

Limited informationabout EE in BATs,in general OK

A lot of informationconcerning EE for eachprocess. A lot of energyrecovery techniques arenot considered BAT yet.

Information about processconversion (technologies) andabout legislation for some EUcountries. Associated withBAT: <3 200 kWh per tonneof chlorine large consumptionof electrical energy

Balance betweenEE and airpollution (forcertaintechniques).Very detaileddescription ofBAT

BAT areconcentrated moreon emissions.Melting processneeds about 75 %of all energyusage

BAT are described butonly a few have a lotof data.The final BATsolution will be a site-specific solution.Calculation model forenergy conservationand savings is given.

Table 9.1: Summary of energy efficiency (EE) aspects in the BREFs

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GLOSSARY ENGLISH TERM MEANING AC alternating current ACkWh alternating current kilowatt hour Adt airdried tonne ASK annular shaft kilns BAT best available techniques BOF basic oxygen furnace BREF BAT reference document CAK chlor-alkali manufacturing industry BREF CLM cement, lime and magnesium oxide manufacturing industries BREF COG coke oven gas CO2 carbon dioxide DC direct current DIP dual in-line package DMB dead burned magnesia EAF electric arc furnace EE energy efficiency EMS energy management system EOS electro optical systems FMP ferrous metals processing BREF GJ gigajoule GLS glass manufacturing industry BREF ICS industrial cooling systems BREF I&S production of iron and steel BREF kg kilogram = 103 gram kWh kilowatt hour LRK long rotary kilns LS liquid steel MC medium consistency MFSK mixed-feed shaft kilns MgO magnesium oxide MJ megajoule MW megawatt = 106 watt MWth megawatt thermal (refers to thermal power produced) n.a. not applicable N2 nitrogen NFM non-ferrous metals industry BREF Ni nickel NOx nitrogen oxide OK other kilns ORC organic rankine cycle PFRK parallel flow regenerative kilns PLC programmable logic controller PP pulp and paper industry BREF PRK rotary kilns with preheater RCF recycled fiber processing SO2 sulphur dioxide VOC Volatile organic compound

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REFERENCES [CLM BREF] The cement, lime and magnesium oxide manufacturing industries BREF

[I&S BREF] Production of Iron and steel BREF

[NFM BREF] Non-ferrous metals industry BREF

[PP BREF] Pulp and paper industry BREF

[CAK BREF] Chlor-alkali manufacturing industry BREF

[FMP BREF] Ferrous metals processing industry BREF

[GLS BREF] Glass manufacturing industry BREF

[ICS BREF] Industrial cooling systems BREF

[ENE BREF] Energy Efficiency BREF

[IMPEL] Energy Efficiency in Environmental Permits, Marianne Lindström et al.