Steam Trace Heating

1 Steam Trace heating2 Spirax Sarco Steam tracing systemsAn efficient and reliable Trace Heating system is a vital componentof the modern process plant. Its use ensures that optimum pumpingviscosity is maintained, product solidification or spoilage does notoccur and damage from adverse ambient conditions is other form of Trace Heating offers the all round benefits of steamin terms of efficiency, low operating costs, controllability,flexibility and above all, Sarco has provided knowledge, service and products for the control and efficient use of Steam intracing systems for over 85 years. We have a wealth of experience in its use in all industries and canprovide the expertise and products to ensure that our customers enjoy its connectorsProvides two bolt quick fit connector for manytypes of isolating valve Steam trapsRemove condensate as soon as it is and damaged by fit swivel connector manifoldsReduced on-site project heat controlsPrevent product energy Sarco tracing system for critical application3 Trap monitoring systemsDetects Steam line balanced pressure Steam trapsRange of capsule and fit swivel connector advantages of Steam Trace Heating areacknowledged by experienced piping engineers and plant operators worldwide:Efficiency.

2 Steam is the most efficient carrier of heat energy. Often, Steam tracing systems can useexcess process Steam that would otherwise go to :Precise product temperatures can be maintained and tracing can be turned on and off automaticallyto suit ambient conditions. Empty product lines can be pre-heated or Steam cleaned without anyproblem. Increased heat demand because of insulation degradation is automatically catered : Steam tracing systems are extremely rugged. Their operation is not affected by adverse conditionsand they easily withstand the normal day to day knocks that occur in a process : Steam tracer outputs are easily adjusted without the need to change the installation . Systemsare easily : Steam is inherently safe and suitable for use in all zones. It is the only totally 'no risk' solutionto tracing : Steam tracing is very simple in its concept.

3 It is easy to design and install and uses simplemechanical components that require no external power lineBlowdown valvesBellows fromtracer lineProductInsulationThe need for Steam tracingSteam tracing is very simple in its principle of operation. When a product in a pipeline is at a higher temperaturethan the air surrounding it, heat will pass through the wall of the pipeline from the product to the surrounding heat loss will cause the temperature of the product to fall. Insulating the pipeline will significantly lower therate at which heat is lost, but unfortunately, no insulation is 100% is a very efficient carrier of heat with a fixed relationship between its pressure and temperature. It cantransport heat over long distances and gives up its heat at a constant make up the heat lost from the product pipeline, small bore Steam pipes, or tracers, are attached to theproduct line.

4 Heat from the Steam passes into the product line and replaces the heat amount of heat transferred, and therefore the product temperature, can easily be controlled by simpleself-acting control systems. The same type of control can also be used in winterization applications, onlyallowing Steam into the tracing line when the ambient temperature falls below a predetermined pipelineAir ventTracing lineSteam inSteamdistribution manifoldSwivelconnectorUTD Steam trapTA10A controlwith ambient sensorProduct lineCondensate outCondensatecollectionmanifoldBlowdown with diffuserSpirax Sarco tracing system for a non-critical applicationUBP30steam trapTypes of Steam heat tracingWe, at Spirax Sarco, are able to provide our customers with advice and products for all types of Steam tracingfrom simple winterization to critical jacketed - used in ultra-critical applications.

5 Usually where a product temperature has to be maintained atan elevated temperature all of the time. The use of a Steam jacket also allows quick pre- Heating of - here, Steam tracing is used to maintain the temperature of a product that will solidify or spoilshould its temperature fall below a predetermined - tracing is used to maintain the product viscosity at its optimum pumping - to ensure pipelines are not damaged due to freezing in adverse weather - small bore Steam tracing pipes, normally 10 mm, used to protect flowmeters, control valves,sampling stations, impulse lines lossfrom productpipelineProduct line5 Determining tracer requirementsCalculating Steam demandTo calculate actual Steam demand, the following simple formulae can be used:-Total Steam demandIndividual tracer Steam demandSteel (NB)Copper (OD)

6 Steam pressure3 bar g 5 bar g7 bar g9 bar g3 bar g5 bar g7 bar g9 bar 1131451251611351741431848010789119961291 0213550791019211810113010914156756587729 7781047558747191801038811441555067577763 8410037475064597667862635354742564864150 - - 8 10 17222532 -- 5 712 161824 Process pipeline diameter100 mm150 mm200 mm250 mm300 mm400 mm500 mmInsulation5010050100501005010050100501 0050100thicknessmmmmmmmmmmmmmmmmmmmmmmmm mmmm25 14 9 2012 24 14 2916 3318 4123 51 2875432659357241874910156123681518210058 3677469755116661357516491201109125714597 5812070145821689420611325213615086541166 9144841749920111324613630116317510062136 8116898202115235131288158352191200115711 5592192112231131268151329181403217 Product / ambientTemperature difference CTable 1 Heat loss from insulated process pipes - W / mTable 2 Output from Steam tracing lines - W / mNote.

7 W / m K thermal conductivity insulation with a medium to low emissivity claddingProducttemperature C = x L x = x L x x n = Steam demand (kg / h) = Heat loss from Table 1 (W / m)L= Length of traced product pipeline (m)hfg= Specific enthalpy of evaporation (kJ/ kg)3 bar g = 2 133 kJ / kg5 bar g = 2 086 kJ / kg7 bar g = 2 048 kJ / kg9 bar g = 2 015 kJ / kgn= Number of parallel tracers per length ofproduct pipelineTo select the size and number of Steam tracing lines required for a particular application, the rate of heat lossfrom the product pipeline under worst design conditions must be rate of heat loss is dependant upon the difference between the product temperature and the ambienttemperature. Other factors such as the thermal conductivity of the insulation, ambient wind speed and the emissivityof the insulation surface will affect this rate of 1 provides heat loss figures for insulated product pipelines up to 500 mm diameter with alternativefigures for both 50 mm and 100 mm thickness Table gives rates for an average wind speed of 10 m / s which will be suitable for most the heat loss per metre from the insulated product pipeline is determined from Table 1, a suitable steamtracing line can be selected from Table 2.

8 In some cases, multiple tracing lines fitted in parallel may be 2 gives practical heat transfer rates from a Steam tracing line into a product line. They already take intoaccount losses from the tracing line to the surrounding air through the use of heat transfer cement as a fillet between the tracer and the product line will increase the rates shownin Table 2 by a factor of at least 2. It will also prevent hot spots and uneven tracer requirements exampleA temperature of 100 C in a 300 mm line needs to be maintained. The minimum design ambient temperatureis -15 C, Steam pressure is 5 bar g and the line is 200 m long. The product line has 100 mm thick insulationwith aluminium low emissivity cladding. Steam tracing lines will be steel, fitted in 50 metre 1 - Determine heat loss from product difference between product and ambient air = 100 C - (-15 C) = 115 Table 1, next temperature difference line (left scale) above 115 C is 125 125 C temperature difference line across table until the figure for 300 mm pipe with 100 mm thickinsulation is off heat loss figure - 94 W / mStep 2 - Select suitable tracer(s)

9 Table 2, select the 100 C product temperature line from the left the line across and read the tracer outputs from the 5 bar g column in the steel tracer mm NB tracer = 50 W / m output20 mm NB tracer = 64 W / m outputIn this instance two 15 mm NB tracers fitted in parallel will be selected to provide the 94 W / m required tomake up the heat losses from the product line. Note that if heat transfer cement were used, only one15 mm NB tracer line would be Sarco Steam tracing productsSpirax Sarco manufacture a range of high quality products for Steam tracing assistance and advice on the most suitable components for your tracing systemplease contact your local Spirax Sarco 3 - Calculate Steam Steam tracer Steam demand Swivel connector Steam trapsSpirax Sarco manufacture a complete range of lightweight,stainless steel Steam traps for tracing rugged design ensures reliable operationunder all operating necessary.

10 Swivel connector Steam traps can be replacedvery quickly without the need to break into the tracing distribution andcondensate collection manifoldsSpace saving forged manifolds with integral piston valveseliminate the need for on site fabrication and in a number of configurations, all with pre-drilledmounting kits and insulating jackets are available to furtherease installation . 94 W / m x 200 m x 32 kg / h2 086 kJ / kg94 W / m x 50 m x kg/h2 086 kJ / kg x 27 Steam trap monitoringSpiratec provides a simple and accurate method of monitoringsteam trap performance under operating will help save energy by reporting Steam traps which havefailed open and protect critical tracing applications byreporting Steam traps which have failed closed. Self-acting temperature controlsSimple, reliable, self-contained temperature control systemsthat are intrinsically safe and require no external TA10 control range, designed specifically for tracingapplications, is manufactured from stainless steel andincorporate a bellows sealed valve arrangement.