Understanding Steam Efficiency IPPTA Conference Kolkata March 2016 Rob Parker – Kadant Johnson

Steam – What we all know It’s hot! It’s expensive! We need it ……a lot of it!

Steam – Usage Major Energy Consumer in Paper Machine Conservation of Steam Use is Key to Competitiveness Usage must be measured Usage must be controlled

Steam – Usage “You can't control what you can't measure” Tom DeMarco Controlling Software Projects, Management Measurement & Estimation (1982), p. 3 What is actually being measured? What does it mean? How can it be controlled?

Steam – Specific Steam Consumption T Steam / T Paper Key indicator for monitoring efficiency All mills have a figure or range Easily available …..Simple?

Steam – Specific Steam Consumption Consider the Variables: Measured Energy Value: All steam supplied to the machine Fuel mass used at boiler x boiler efficiency Steam supplied only to the dryer section Measured Production Value: Finished Paper Throughput Pope Reel Throughput

Steam – Specific Steam Consumption Consider the Time Period: Daily Average Monthly Average Sheet-On Stable Production

Steam – Specific Steam Consumption Consider the Moisture: Press moisture affects steam consumption significantly 1% moisture increase = up to 5% steam increase Analyse steam consumption compared to H 2 O evaporated for meaningful benchmarking

Steam – Benchmarking Moisture Ratio: (% Dry Out / % Dry In) – 1 EG. Kraftmill, 93% Popereel, 49% Press (93 / 49) – 1 = 0.89 T Steam / T H 2 O Evap

Steam – Benchmarking Good level for steam consumption / water evaporated: 1.35 EG. Same Kraftmill – 1.35 x 0.89 = 1.20 T / T 100% efficiency, m/c draw, sheet-on, dryers only T Steam / T H 2 O Evap

Steam – Benchmarking For sized grades there are different considerations: 75gsm sized copier grade, size application of 7% solids 3.5m wide sheet, 500m/min Press Dryness 43.0% Pre-Size Press 95.0% Sheet Weight – 73gsm Exit Size Press70.2% Pope95.0% Sheet Weight – 75gsm T Steam / T H 2 O Evap

Steam – Benchmarking Production rate for each section should be calculated: Pre-dryer 73gsm x 3.5m x 500m/min = 7665 kg/hr Post-dryer 75gsm x 3.5m x 500m/min = 7875 kg/hr T Steam / T H 2 O Evap

Steam – Benchmarking Evaporation rate for each section should be calculated: Pre-dryer (95 / 43) - 1 = kg/hr x 1.21 = 9275 kg/hr H20 Evaporated Post-dryer (95/70.2) – 1 = kg/hr x 0.35 = 2756 kg/hr H2O Evaporated T Steam / T H 2 O Evap

Steam – Benchmarking Evaporation rate for each section should be calculated: Pre-dryer (95 / 43) - 1 = kg/hr x 1.21 = 9275 kg/hr H20 Evaporated Post-dryer (95/70.2) – 1 = kg/hr x 0.35 = 2756 kg/hr H2O Evaporated T Steam / T H 2 O Evap

Steam – Benchmarking Total machine evaporation = kg/hr At 1.35 T Steam / T H2O Evap = kg/hr Divided by machine production of 7875kg/hr Good Consumption: 2.06 T Steam / T 100% efficiency, m/c draw, sheet-on, dryers only T Steam / T H 2 O Evap

Steam – Benchmarking Steam consumption for dryers only is benchmarked If < 1.35, other inefficiencies should be targeted. If > 1.35, steam and condensate system needs to be examined T Steam / T H 2 O Evap

Steam – Benchmarking Also monitor: Press Performance – samples to TAPPI standards % Downtime (sheet breaks) % Downtime (shuts/breakdowns) %Finishing Losses Steam flows to ancillary users – PV system, Starch Cooking, Silo Heating

Steam – Flow Measurement Accuracy Check Points: Orifice Plate Installation Flow Transmitter Installation Orifice Plate Specification Density Compensation Correct Steam Quality

Steam – Flow Measurement Accuracy Check Points: Orifice Plate Installation Flow Transmitter Installation Orifice Plate Specification Density Compensation Correct Steam Quality

Steam – Flow Measurement Accuracy Check Points: Orifice Plate Installation Flow Transmitter Installation Orifice Plate Specification Density Compensation Correct Steam Quality

Steam – Flow Measurement Accuracy Check Points: Orifice Plate Installation Flow Transmitter Installation Orifice Plate Specification Density Compensation Correct Steam Quality

Steam – Flow Measurement Accuracy Check Points: Orifice Plate Installation Flow Transmitter Installation Orifice Plate Specification Density Compensation Correct Steam Quality

Steam – Reducing Usage in System Flash Steam and Heat Recovery Minimise Number of Dryers Draining to Condenser Install Stationary Syphons Minimise Venting to Condenser Eliminate Traps blowing to drain Ensure Dry Steam in Supply Good Pipe Insulation Also……condensate return, condense and return to boiler house!

Steam – Flash Steam Recovery Example >800TPD linerboard machine 7 bar(G) in dryers No flash recovery – venting to overloaded condenser Installed flash recovery vessel Use flash in steam box Around 5% saving in steam consumption

Steam – Flash Steam Recovery Example <300TPD kraft machine <3 bar(G) in dryers Lots of vented steam due to passing steam traps Heat transfer for drying is very good Installed dP style system with stationary syphons Installed flash recovery systems Steam consumption reduced >10%

Steam – Conclusion Measure Accurately Benchmark Consistently Target Problems Effectively Reduce and Control Usage

Understanding Steam Efficiency