Pulp & Paper - tranter.com

1 IN THE pulp AND Paper industry PRIME SURFACEHEAT EXCHANGERSPLATE & FRAMEHEAT EXCHANGERSALL-WELDED PLATEHEAT EXCHANGERS BULLETIN NO. TIS-105 AHEATsEXCHANGERSHEATsEXCHANGERS THE heat transfer peopleTRANTER BRINGS EFFICIENCY AND RELIABILITY TO THE pulp AND Paper INDUSTRYNOTE: THE DIAGRAMS SHOWN ARE PURPOSELY BRIEF: NO ATTEMPT HAS BEEN MADE TOSHOW ALL THE VALVES, PUMPS, CONTROLS, ETC., THAT MAY BE REQUIRED. IN MOST SYSTEMS,ALL PIPING ACTUALLY IS FROM THE SUPERCHANGER FIXED FRAME. THIS FACILITATES OPEN-ING THE UNITS, WHEN REQUIRED, WITHOUT DISASSEMBLING plate and frame units are the best choicebecause they give you: (1) higher U values typically 3 to5 times greater than shell-and-tube; (2) a unique turbulentflow design resulting in lower fouling; (3) closer temperatureapproach capability of less than 2 F, compared to the typi-cal 10 F or higher with shell-and-tube; (4) space savingsof 50% to 90% over shell-and-tube.

2 (5) expandability andeasy servicing, and (6) immediate availability, since they are made in the ALL-WELDEDPLATE HEAT EXCHANGERSW here space is at a premium, or gasket limitations prevent the use of a SUPERCHANGER unit, the compactall-welded MAXCHANGER unit may be the best solutionto many pulp and Paper PRIME SURFACE HEATEXCHANGERSA multitude of design configurations and over 300 differ-ent sizes make PLATECOIL units ideally suited for a vari-ety of applications in the pulp and Paper industry . Theyoffer versatility in providing the heating and/or cooling required for various applications in the units are perhaps best known as immersion-type, in-tank or as clamp-on heaters for maintaining prod-uct temperatures in tanks.

3 Their use goes far beyondthese applications, however, and includes designs for custom-engineered processing units can be fabricated from most weldablemetals including carbon steel, stainless steel, titanium,Monel, nickel and various special corrosion-resistantalloys. Surface finishes are available in great variety to minimize fouling and reduce PLATE & FRAMEHEAT EXCHANGERSP late and frame heat exchangers provide a more efficientand cost effective means of heat transfer than old, tradition-al shell-and-tube exchangers. This is particularly true inthe pulp and Paper efficiency and heat are critical needs today in the pulp and Paper industry . Tranter provides these benefits and more, with PLATECOIL, SUPERCHANGERand MAXCHANGER heat exchangers that are standards for the THE BOILER ROOM: HEATINGMILL WATER WITH STEAMIn this application, the SUPERCHANGER heat exchanger shigh heat transfer rates result in a compact, low cost, corrosion-resistant heater.

4 Steam temperatures need to belimited to about 350 F. Also, the water should be treatedto minimize scaling on the WaterTankPulpWaterStock InletFourdrinierScreenWhite Water ReturnSuction RollMixerAT THE Paper MACHINE (FORMINGSECTION): HEATING WHITE WATERWITH HOT WATERW hite water from the Fourdrinier frequently needs to bereheated before reusing. In this application, the use of hotwater rather than steam is preferable to reduce scaling tendencies. The hot water may be supplied by a SUPERCHANGER unit heating water with steam or as a hot waste stream as alternates to the hot water supplytank as WaterCondensateTreatedWaterSupplyHotWate rStorageTankSUPERCHANGERB lack LiquorTankWater Jacketed SpoutFor Smelt DischargeTower WaterBoiler UsingBlack LiquorFuelDemineralized Water LoopGreenLiquorStorage3 TYPICAL HEATING APPLICATIONS123To WasherAnd FurtherProcessingCooling TowerSUPERCHANGERS odium HypochloriteStock ChestCaustic (Sodium Hydroxide)Gaseous ChlorineMixingTankIN THE pulp MILL.

5 COOLINGBLEACH SOLUTIONS DURINGMIXINGWhen chlorine gas is injected into sodium hydroxide to makesodium hypochlorite for bleaching, heat is generated bythe mixing process. SUPERCHANGER plate and frameheat exchangers with titanium plates are very effective inremoving this heat. When other chemicals are handled in a similar manner, special metals are available for plates as needed. The high U values obtained with the SUPERCHANGER design help keep costs down becauseless area is required than with shell-and-tube THE BLACK LIQUOR RECOVERYDEPT: INTERCOOLER FOR CLOSEDLOOP COOLING (ISOLATION)After black liquor (spent cooking liquid) from digesters isconcentrated in the evaporators, it is burned as a boiler chemicals (smelt) are discharged through a spoutwhich generally requires cooling.

6 To keep the water jacketclean, demineralized water is recirculated through it. Thiswater can be cooled by means of a SUPERCHANGER heatexchanger which uses tower water (or any cooling water).The characteristic close approach temperatures obtainedwith SUPERCHANGER units make this an ideal COOLING APPLICATIONSSUPERCHANGER UNITSSUPERCHANGERB lowdownVentFlashTankTo DrainSupply WaterPreheatedWaterDeaeratorTankVentBoil erBoilerFeedwaterIN THE BOILER ROOM: HEATRECOVERY FROM BOILERBLOWDOWNThis is a common application for SUPERCHANGER units and is applicable to surface blowdown flash tank will generally reduce the pres-sure and temperatures below the 350 F gasket tem-perature limit.

7 Wastewater temperatures are reducedto meet environmental requirements and rapid pay-back is WaterCondenserBlow LineFromDigesterSUPERCHANGERSS upply WaterBoilerFeedwaterBrown StockWashersTo Waste OrRecyclingFlashed Steam150 F100 F104 F80 F100 FStock ToWashers180 FAccumulatorBlowTankSUPERCHANGERB lack LiquorRecovery BoilerWet ScrubberTo ProcessTo ProcessWater SpraysSupplyWaterStack GasExhausts70 F140 F78 F34 FHotWaterTankAT THE BLACK LIQUOR BOILER:HEAT RECOVERY FROMSCRUBBER WATERWhen water is sprayed into hot stack gases, its temperature increases. Rather than waste this scrubberwater, it can be passed through a SUPERCHANGER plate and frame heat exchanger as shown.

8 Typicaltemperatures, as shown here, demonstrate that plantwater can be heated about 44 F by this waste one case, the recovery is about 60,000,000 is an excellent application for SUPERCHANGER units with fast HEAT RECOVERY APPLICATIONS67 SUPERCHANGERS econdaryTreatmentPrimary ClarifierTo WasteHotWaterTankSupplyWaterStrainerTemp s Shown AreTypical For SummerDe-inking AndDe-fibering Process90 F110 F75 F95 F85IN THE pulp MILL (BLOW HEATRECOVERY): HEAT RECOVERYFROM DIGESTER GAS CONDENSATEAs illustrated here, two SUPERCHANGER units saveover $300,000 per year through enhanced heat is possible due to the installation of a condenser incombination with the SUPERCHANGER , digester gases with entrained moisture andsome 13,000,000 BTU/hr were discharged directly intothe atmosphere.

9 The plates are electropolished to helpreduce scaling and a back-flush system is used regular-ly. With these safeguards, fouling is not a MILLS REWORKING WASTEPAPER: HEAT RECOVERYFROM DE-INKING EFFLUENTI llustrated is just one example of how a SUPERCHANGER plate and frame heat exchanger recovers millions ofBTUs from the numerous hot, dirty waste streams inpulp and Paper mills. Frequently, a dual purpose isserved since wastes must be cooled before dischargefor environmental reasons. While recovering useful heatat the same time, the payback for SUPERCHANGER heat exchangers and related equipment is very following products also can be heated with SUPERCHANGER units using steam or hot water.

10 Design considerations outlined on this page should be followed: Glue Resin Fuel Oil Tall Oil Polyvinyl Alcohol for Coatings River Water Sodium Hydroxide Calcium SulfaceTYPICAL HEAT RECOVERY APPLICATIONSADDITIONAL SUPERCHANGER HEATING APPLICATIONS5As indicated by the heating, cooling and heat recoveryapplication examples, SUPERCHANGER plate and frameheat exchangers perform efficiently in a diverse range ofconditions. Experience has shown that adherence to thefollowing guidelines will result in optimum Design with washboard models and with velocities as high as practical when fluids containing suspendedfibers are The use of hot water rather than steam to heat white water will result in fewer scaling Some fluids have tendencies to develop scale at elevated temperatures.