The brewing industrysteam and condensate systems

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Pressure bar g

Steam saturationcurve

00 2 4 6 8 10 12 14 16

200

150

100

50

250

To enable temperatures to be controlled accurately itis essential that high quality dry saturated steam isdelivered to the process at the correct pressure. Anyentrained moisture or incondensable gases in thesteam could lower its temperature or impair the heattransfer rate. This will make accurate control difficultand in some cases it may not even be possible toachieve the desired production techniques.

What is steam used forBrewing is an ancient art where beer is prepared frommalt, hops, water and yeast.

During the brewing process complex chemicalreactions take place that convert these raw ingredientsinto beer. Steam is essential in this process for heating,cleaning and pasteurisation.

The need for high quality steamSteam is used because it is an efficient carrier of heat.

It is produced in the boiler and carried to the brewingequipment by a pipework distribution system. At theprocess it gives up heat and condenses.

A very important property of saturated steam is that itstemperature is directly related to its pressure.Therefore, the temperature of the various processescan be accurately controlled by controlling the pressureof the steam.

Most breweries will distribute steam at a pressurebetween 7 and 10 bar. The pressure will then bereduced at each process to the optimum level.

Steam

Copper vapours

Condensate

Wort

Tem

pera

ture

°C

The well managed use of high quality steamis a major factor in producing premium qualitybeers efficiently.

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Spirax Sarcoin the brewing industry

For most of the 20th century Spirax Sarco has been the leaderin improving steam plant efficiency, providing knowledge

and high quality products to all branches of industry,including the brewing industry.

We understand that the brewing industryhas its particular needs and problems, and that

each application within the industry has its own specialrequirements.

We provide solutions to problems throughout thecomplete steam and condensate system in the brewing industry,

anywhere in the world.

The complete systemTo produce high quality beer while maintaining low production costs it is essential that the brewing processesare operated as efficiently as possible, effectively using the heat available in the steam.

To achieve this, it is necessary to consider the design and operation of the complete steam and condensatesystem, taking into account the types of processes, their individual requirements, the local environment and thetypes of beer being brewed.

Consideration should also be given to future expansion plans and plans to upgrade existing equipment.

Steamdistribution

Steam controland

management

Condensatemanagement

Steamgeneration

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Spirax Sarco and steam generation

Cold water make-up controlsBoiler feedtanksFeedtank controlsDeaerator headsAir vents and vacuum breakersFeedtank recirculation systemsBoiler blowdown heat recovery systemsVent headsSteam injection systemsBoiler blowdown systemsBlowdown vesselsBlowdown inlet manifoldsLevel controls and alarm systemsTDS control systemsTDS measurementFeedpump check valvesSample coolersFlash vesselsResidual blowdown heat exchangersCooling water systemsSteam main start-up systemsCondensate contamination detection systemsCondensate dump valves

steam flash steam condensate

Steam leaving the boiler house should contain as littlemoisture and incondensible gases as possible. Thiswill ensure that the maximum amount of heat isavailable and minimise the risk of pipeline andequipment damage from water hammer.

Spirax Sarco has the expertise to help you producehigh quality steam from your boilers, at the mosteconomical cost, with a wide range of productsspecifically designed for the boiler house, allmanufactured to the highest standards.

We have literature on boiler house applications andequipment freely available upon request.

An essential part of the boiler house design andoperation is ensuring the boiler operates at the highestpossible efficiency. Every effort should be made torecover and reuse the heat available from secondarysources such as boiler blowdown. Your local SpiraxSarco engineer will be able to help and offer advice onhow this can be achieved.

Supplied by Spirax Sarco

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The boilers should be operated at the highest possiblepressure to provide a degree of thermal storage,

helping to cope with sudden high steam demands.Steam pressure can then be reduced to the requiredoperating pressures.

Thermal storage can be furthered increased byspecifying a larger than normal boiler shell orintroducing a steam accumulator. An accumulatorstores thermal energy under light load and supplementssteam flow to the brewery during sudden high loads.This will protect the boilers from the effects of overloadconditions, allow them to fire to the average load andensure that a high sudden steam demand is met.The use of surplussing valves to restrict steam flow toa safe maximum or to shut the supply to low priorityusers during peak demands can also be an effectiveway to protect the system.

Boiler water level controlsBecause of the large boilers and variable steamdemand found in a brewery, careful considerationshould be given to the selection of boiler water levelcontrols. These should be of the modulating type, withtwo element control preferred for reliable operationunder heavy load conditions.

Boiler loading without accumulatorBoiler loading with accumulator

Steam qualityHigh sudden peak demands for steam in a brewerycan lead to priming or carryover from the boilers, withvery wet steam passing into the distribution system.Various methods are available to minimise thedamaging effects these sudden high peak loads canhave on brewery operation.

Spirax Sarco accumulator control

Pressure reducingvalve set

Accumulator charging valve Accumulator discharge valve

Overflow

Steam flow

to system

Accumulator

Steam flow

from boiler

Controller

Pressuresensor

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Steam

Liquor

Level control system

Condensate

Steam trap set

Self-actingtemperature

control

Pressure reducingvalve station

Spirax Sarco hot liquor tank controls

Mash tun and boiler

Copper control panel

Condensate

Calandria

Steam trap set

Flowmeter

Spirax Sarco calandria control

Wort

Brewingcopper

Pneumatic actuatedvalve with positioner

Spirax Sarco a

Lauter tun Cooler

Calandria Copper

Hop strainer a

Steam

Readout unit and 4-20 mA output

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Spirax Sarco clean steam station

Pressure reducingvalve station

Clean steam filter

Clean steamFactory steam

Condensate

Steam trap set

nd the brewery

nd separator Cooler CoolerFermentationvessel

Conditioning tank

Pasteuriser

Flowmeter

Cooling return

Cooling flow

Readout unit with4 -20 mA output

Sensor

ControllerPneumatic actuatedvalve with positioner

Spirax Sarco fermentation vessel controls

N2 purge

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Steam distribution

From the boiler house the steam is carried to thevarious processes within the brewery by the distributionsystem, where it should be available at the correctpressure, in sufficient quantity and in the best possiblecondition.

It is important that pipework carrying steam from theboiler house to the equipment is sized correctly. Steamvelocity should be at a reasonable level and thepressure drop kept to a minimum. Spirax Sarco will behappy to advise on your distribution pipework sizing.

The installation of accurate steam metering equipmentwill enable you to monitor performance, assist in energymanagement and provide information that will help inthe accurate costing of beer production.

To ensure that radiation losses are kept to a minimumthe steam distribution system should be insulated. Evenwhen insulated some radiation losses will occur, withsome steam condensing and forming condensate inthe pipework.

It is important that this condensate is removed so thatthe steam arriving at the processes is as dry aspossible. The removal of condensate from thedistribution pipework is also necessary to preventdamage from waterhammer. This occurs when slugsof condensate are propelled along the pipeline at steamvelocity.

Condensate can be removed by means of a separatoras shown in the illustration of a steam metering station,and in the case of long distribution runs, a relay drainpoint should be installed. Provision should also be

Spirax Sarco relay point

Airvent

Steamflow

Steamflow

Condensate out

Steam trap set

The cause of waterhammer

If it is not removed, a slug of condensate can develop and be carriedalong the pipe at steam velocity.

Condensate forms due to radiation losses from the pipe

Airvent

Steam flow Steam flow

Spirax Sarco steam metering station

Condensate out

Various outputsAlarms

TimersR232C Interface

Spiraflometer

Steam trap set

Wafer checkvalve

Separator

made for removing air and incondensable gases fromthe steam distribution system through strategicallyplaced thermostatic air vents.

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Steam pressure control

Where is steam usedA large proportion of the steam produced in a brewery isused to help in the extraction of sugars and flavours inthe mashing process and for wort boiling where the beeris sterilized and stabilised. These two processes alonecan account for up to 50% of the connected steam load.

Steam is used to provide the heat for :PasteurisationProduction of hot liquor

Different types of steam pressure reducing valves areavailable, from simple direct acting valves to moreflexible pneumatic actuator, valve and electro/pneumatic positioner combinations.

The type of system should depend on the needs ofthe process. Spirax Sarco supply many different typesof steam pressure control system and can advise onthe best choice for a particular application.

Bottle washing; in the racking,Bottling and canning processesThe CIP systems.

In addition to the process requirements steam will oftenbe required for the heating and air conditioning systemin a brewery. Spirax Sarco has extensive experiencein this area and can provide advice on the use of steamin heating and air conditioning applications.

Safety valve

Steam flowSteam flow

Air vent

Steam trap set

Condensate

Direct actingreducing valve

Spirax Sarco direct acting reducing valve station

Spirax Sarco electro /pneumatic reducing valve station

Steam flowSteam flow

Air vent

Safety valve

Steam trap set

Condensate

Pneumatic valve and actuator with positioner

Controller

Separator

Separator

Pressure sensor

Saturated steam is used in a brewery at various pressuresdependent upon the individual requirements of thedifferent processes. The pressure requirements of theseprocesses can range from under 1 bar to over 5 bar.

Steam should be generated at the highest possiblepressure and then reduced to meet the processrequirements. This will help with the problem of peakloads and keep the distribution pipework size as smallas possible.

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Temperature controlMost of the steam using processes found in a brewerywill require a temperature control system to ensure thatthe product is heated up to and maintained at thecorrect temperature.

Spirax Sarco provide many different types oftemperature control system and will be able torecommend the most suitable for each of the manydifferent processes.

A simple, robust self-acting control system will oftenbe the most suitable for a hot liquor tank, while a moresophisticated electro / pneumatic system will berequired on a mash tun to ensure that all of the

Plate heat exchangersPlate heat exchangers are used throughout a breweryin a variety of heating and cooling applications.

In heating applications steam is frequently used as theprimary medium. It is easily controlled and its excellentheat carrying properties allow pipe and exchanger sizesto be kept to a minimum.

A temperature control valve constantly adjusts theprimary steam flowrate and pressure to compensatefor fluctuations in the secondary fluid's inlet flowrateand temperature. This will ensure the product flow fromthe exchanger is always at the correct temperature.

Spirax Sarco plate heat exchanger temperature control and condesate drainage

When steam gives up its heat it condenses and thiscondensate must be drained immediately to allowsteam to continue to enter the exchanger and carry onthe process. If condensate is allowed to remain in theexchanger, poor temperature control will result andthere will be an increased possibility of damage fromwaterhammer.

If the correct type of steam trap is selected and providedthe pressure in the steam space of an exchanger ishigher than the pressure in the condensate returnsystem, condensate will drain from the exchanger assoon as it has formed.

Typical mash tun temperature profile

Pneumatic valve andactuator with positioner

Plate heat exchanger

Pressurepoweredpump

Condensate

Steam flow

Secondary flow out

Secondary flow in

Controller

Steamtrap

Condensate

100

80

60

40

20

0

0 3 21 6 4 5 8 10 9 7 12

Hours

11

°C

Steam supplyto pump

appropriate rests are maintained at the correcttemperature for the correct time.

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Low pressure flash steam

Steam trap set

Condensate fromhigh pressuresteam

Spirax Sarco flash steam recovery set

Condensate out

Flash vessel

Vent

Condensate in

Spirax Sarco pressure powered pump condensatereturn unit.

Condensate out

Overflow

Pressurepoweredpump

The pressure inside the steam space of a plate heatexchanger is never constant, and can even fall into avacuum condition under light loads. When the pressurewithin the condensate return system is greater thanthe pressure within the exchanger steam space, theexchanger is described as being in a 'stall' condition.In this condition condensate will not be able to drainfrom the exchanger.

Condensate managementHeat recovery

Approximately 25% of the heat used to generatesaturated steam at 5 bar remains in the condensatewhen the steam condenses. In effective condensatemanagement, consideration should be given torecovering and using as much of this heat as possible.

Flash steam recoveryFlash steam is released from the condensate when itspressure falls. Typically this happens when it passesfrom the process, through a steam trap, to a lowpressure condensate system. Low pressurecondensate has a smaller sensible heat content thanthe high pressure condensate and this sudden excessheat content will cause some of the condensate to 'flashoff' into steam at the lower pressure.

Flash steam recovered in this way can be used tosupplement the steam supply to applications thatrequire low pressure steam such as hot liquor tanks.

Condensate returnThe final stage in condensate management is to returnas much condensate back to the boiler house as possible.

Even after flash steam has been recovered, the lowpressure condensate still contains sensible heat - over400 kJ/kg at atmospheric pressure; and will requireno further boiler feed treatment before it re-enters theboiler.

Methods of returning condensate can include simplegravity return systems, electric pumping systems orsystems incorporating the versatile Pressure PoweredPump.

Spirax sarco will be pleased to advise on themost cost effective means of achieving ahighly efficient condensate return system.

A simple and effective solution to this common problemis to install a combination pump/steam trap unit. Thiswill ensure that condensate is drained from the heatexchanger under both normal and 'stall' operatingconditions.

Spirax Sarco can advise on whether a 'stall' conditionmay occur on a heat exchange application and how toensure its adverse effects are avoided.

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Spirax-Sarco Limited, Charlton House,Cheltenham, Gloucestershire, GL53 8ER UK.

Tel: +44 (0)1242 521361 Fax: +44 (0)1242 573342E-mail: enq@spiraxuk.attmail.com

Internet: www.spirax-sarco.com© Copyright 1999 Spirax Sarco is a registered trademark of Spirax-Sarco Limited

SB-GCM-08 CM Issue 1

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Spirax Sarco provides knowledge,service and products worldwide for the control

and efficient use of steam and other industrial fluidsin the brewing industry.

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As your business partner, Spirax Sarco will provide you with:-

l Worldwide support from a team of 3 500 dedicatedemployees.

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A further 46 agencies operate throughout the world.If you have difficulty finding a local contact please fax us at the number shown below.