Program Name or Ancillary Texteere.energy.gov Process Heating Assessments Michael R. Muller USA...

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Process Heating Assessments

Process Heating Assessments

Michael R. MullerUSARutgers University, Center for Advanced

Energy Systems

U.S.- Brazil Industrial Energy Efficiency WorkshopRio de Janeiro , BrazilAugust, 2011

2 | Industrial Energy Efficiency eere.energy.gov

• Introduction• Elements of an ESA in Process Heating• The PHAST Tool• Case Study: Powder Processing• Case Study: Cast Iron Pipes

Outline


What Is Process Heating ?

FurnacesOvensHeatersKilnsDryers

Supplying heat to materials using

for further processing in manufacturing operations


Importance of Process Heating

ProcessCooling

1%

Process Heating 38%

Steam 35%

Other4%Electro-chemical

2%

Motor Systems

12%

Facilities 8%

Manufacturing Energy Use by Type of System

(%)


• Hot = Metal Melting– Blast furnaces: 900 °C to

1300 °C (1600 °F to 2300 °F)

Process Heating Temperatures


• Low Temperature Drying Processes: 70 °C (160 °F)

Low Temperature Processes


Energy distribution in a typical heating system

Furnace Heat Input

Heat inFlue Gases


“Save Energy Now” Energy Assessments

• Assessments of targeted industrial systems by Qualified Specialist using the DOE software tools

• Energy Assessment Report identifies potential energy and cost savings

• Plants are selected by DOE based on several factors, including: The plant’s energy consumption The company’s intention to include other similar plants

within their company

8


A Process Heating ESA

Conduct Plant Visit

Analyze and Report Results

GatherPreliminaryData

Follow-up

Train Plant Staff

• Teams are DOE Energy Experts and plant personnel

• Teams focus only on process heating systems

• Plant personnel trained on DOE software tools


Energy Expert spends 3 days on site

Day 1• Safety briefing, tour plant• Overview of DOE PHAST Tool to plant personnel• Agree on potential energy efficiency

opportunities to investigate• Initiate data collection for potential opportunities

Day 2• Continue data collection• Apply PHAST tool to quantify potential

opportunities• Plant lead and expert agree on opportunity

results

Day 3• Wrap up tool analyses• Plant lead and expert ensure they agree on

opportunity results• Closeout meeting in p.m. to review results


• The Process Heating Assessment and Survey Tool (PHAST) was developed by Oak Ridge National Laboratory in cooperation with the Industrial Heating Equipment Association (IHEA).

• A subcommittee consisting of members from major industries (i.e., petroleum refining, chemical) and equipment suppliers acted as an advisor during the tool’s development.

• Development efforts were supported by The Office of Industrial Technologies Program (ITP) of the US Department of Energy (DOE).

What is PHAST?

Process Heating Assessment and Survey Tool (PHAST)


• A tool that can be used to: – Estimate annual energy use and energy cost for

furnaces and boilers in a plant – Perform detail heat balance and energy use analysis

that identifies areas of energy use, efficiency and energy losses for a furnace

– Perform “what-if” analysis for possible energy reduction and efficiency improvements through changes in operation, maintenance and retrofits of components/systems

– Obtain information on energy saving methods and identify additional resources

What is PHAST?

Process Heating Assessment and Survey Tool (PHAST)


• Where: Delaware, USA• What: Microcrystalline Cellulose• How: Wood pulp is cooked with bleach, caustic soda and

steam

– then spray dried

Case Study


• Cellulose reacts with chemicals at 50°C for 2-3 hrs.– the reaction changes the physical form from fiber to powder

• Slurry is then pumped to a spray tower where it is dried by heated air– NOTE – the dryers evaporate water from the slurry, and

therefore remove water at below boiling temperatures • it was necessary to make adjustments to the PHAST inputs

because water removed from process stream is required to be at 100 °C

• Resultant power retains water absorbency which is very useful

Case Study


• Two of three dryers had waste heat recovery using a glycol loop

• Third dryer had no space for air preheat– But, waste heat could be used to preheat other two dryers!!

• Plant had not included energy associated with evaporation in their analysis

Waste Heat From Dryers

Slurry Inlet - powder and water

Air Inlet

Air Preheat - glycol Loop

Air Heating

(Nat Gas)

Dryer Wet Air

Glycol Loop

Exhaust Air

Product


Data Logger Results

• Temperature sensors on two cooling loops overnight shows correct behavior (upper) and total valve failure (lower)

• Multiple days were needed to be able to see this


Results For Powder Processing

IDENTIFIED PLANT BEST PRACTICES

1 Instrumentation and control of key systems 2 General use of waste heat throughout plant 3 Aggressive paybacks for energy projects (3 years) 4 Level of insulation on dryers is high – can allow them to live outdoors 5 Compact plant design is efficient, although making changes in such close quarters is difficult

ENERGY SAVINGS OPPORTUNITY SUMMARY INFORMATION

Identified Opportunity

Savings/yr $ kWh MMBtu Fuel Type N,M,L

Increase rate of scrubber flow to increase recovered heat in glycol loop

$57,600 4800 Nat Gas N

Repair observed missing insulation $3360 280 Nat Gas N Lower O2 in flue gas to 2% from 3.5% $95,000 7919 Nat Gas N Recover Waste Heat from Bowen Dryer $260,323 21694 Nat Gas M Use organic rankine cycle engines to make power from low quality waste heat sources

$106,000 1,000,000 Electricity L

Replace heat exchangers for city water and purified water to directly heated systems

$286,010 23834 Nat Gas M

Use 20% of exhaust gas as recirculation $160,000 13,333 Nat Gas L Eliminate flash steam – use in other processes $159,428 13,285 Nat Gas M


• Where: NJ, USA• What: Cast Iron Pipe for Water Systems• How: Cupula Furnace and Annealing Oven

Case Study


• Cast iron is made from pig iron in a tall furnace• Liquid cast iron is spun into a pipe form• Concrete is sprayed on the pipe and provides a coating• Cold pipes are then painted

Case Study


• Major savings were identified by annealing pipes before they cooled down

• Plant felt mixing pipe sizes in the ovens let them be more fully utilized– But to do this there were long waiting times and pipes

cooled to nearly room temperature

Melt Room and Annealing Disconnect


• Natural gas use was monitored closely for three days

• Comparing to bills showed large amount of natural gas use unaccounted for

• Cause is failure to setback ovens when not in use

Ghost Use of Natural Gas


Results for Iron Pipe Foundry

ENERGY SAVINGS OPPORTUNITY SUMMARY INFORMATION Identified Opportunity

Savings/yr

$ kWh MMBt

u Fuel Type

N,M,L

Use moving walls or flaps or at least reflectors to limit radiation energy loss from both ends

$21586 1440 Nat Gas N

Review and update control scheme to insure temperatures/burner settings are accurate

$70153 4680 Nat Gas N

Improve annealing oven operation to eliminate push-pull $259,000 17,280 Nat Gas N

Track and Eliminate “Ghost” Natural Gas Use

$570,000 38000 Nat Gas N

Use solid state humidity sensors as feedback on concrete dryers

$3780 252 Nat Gas N

Repair oven hot spots $4300 317 Nat Gas M Evaluate operations and model processes to optimize performance proactively

$158,000 9415 Coke/Nat

Gas M

Utilize waste heat from oil cooler and water jackets to make electricity

$215000 1,440,000 Electricity L


• Process heating assessments can find very large savings for plants

• Some important recommendations require the three days to be observable

• Using the PHAST tool can quantify savings – Works best on very hot processes

• Training plant people on gathering data and analyzing data can have lasting impacts

Conclusions


Obrigado!!

Perguntas???

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