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- 1. Concept Notes forDesign of Utility Distribution Systems By santosh
- 2. Contents • Introduction toConcept note • Kissan Fats Pvt. Ltd – Background – Boiler house – Steam distribution – Condensate recovery • Calibre chemicals Pvt. Ltd – Background – Boiler house – Steam distribution – Condensate recovery • Oswal Apparels Pvt. Ltd – Background – Boiler house – Steam distribution – Condensate recovery – Compressed air system – Effluent heat recovery • Techincal design background – Steam line sizing – Good engineering practices – Steam traps selection – Condensate line sizing – CRS equipment selection
- 3. Design Concept Note •Purpose: To explain to the client the importance and implications of the design/changes suggested in the system • Objective: To highlight the key design considerations and benefits to the customer in engineering the Steam and Condensate Loop – Plant operations » Ease of Operation » Ease of Maintenance » Safety » Future Expansion » Routing limitations » Any other – Process parameters » Pressure » Temperature » Flow • Projects: – Re-engineering at: • Kissan Fats Pvt. Ltd • Calibre Chemicals Pvt. Ltd – Green Field Project • Oswal Apparels Pvt. Ltd
- 4. Kissan Fats Pvt.Ltd • Background: – Three units: SEP, Refinery, Rice Mill – Presently Steam generated from two boilers 6TPH and 8TPH @ 17.5kg/cm2g – Up-gradation to Co-generation unit – Rice mill driers changed to steam heating from thermic fluid – Vacuum systems of Refinery changed from 10barg to 4barg – Pumping condensate through trap pressure – Re-engineering of steam distribution system – Effective condensate recovery system design
- 5. Steam supply conditions 10kg/cm2g 5TPH 4kg/cm2g 17 TPH Back pressure Turbine 2.2MW DSH PRS DSH 10kg/cm2g 17TPH 67kg/cm2g 17TPH 470 DegC 191 DegC 4kg/cm2g 18 TPH Power boiler 67kg/cm2g Capacity: 22TPH Fuel: Rice Husk 340 DegC 230 DegC Water @105 DegC 1153kg/hr Water @105 DegC 4347kg/hr
- 6. Rice mill cookers SEP plant Refinery PRS PRS 8TPH boiler @17.5kg/cm2g Max17TPH Min 5 TPH Hot water Tanks 4kg/cm2g 18 TPH Rice Mill SEP Refinery Direct Steam Flash steam Deaerator@0.3barg Rice mill Driers x 5 nos FV PPPU FV PPPU FV FV PPPU FV To DA To DA To DA Flash steam Flash steam To DA 10kg/cm2g 5 TPH
- 7. Boiler/Turbine house • Operateability –Three operating conditions • Turbine • Power boiler • Existing boiler – Deaerator level control to accommodate condensate – Bypass condensate from deaerator to Feed water tank of 8TPH • Future expansion – Spare nozzles on Steam Header – NRV installed on steam outlet lines
- 8. Steam Distribution • Operateability –Temperature control valve module for hot water tanks – Synchronization of TC make-up valve and PRS • Future expansion – Spare nozzles for future equipments – Expansion of rice mill, existing and new steam lines checked for max steam flow • Safety – Safety Valve downstream of PRV – Ex-proof SFM and control valve • Energy efficiency – Utility monitoring system, SFM, CRM – Air vents provided for quick start-up – Insulation of lines to minimize condensation and radiation losses • Other Considerations – Piping from boiler to turbine by BV – Controls for direct steam injection by BV – Existing lines checked for max flow rate, change suggested where necessary – Resizing of main steam lines – For DO, PRS to be checked for capacity – Routing and supports scheme – Pressure and Temperature gauges on headers
- 9. Condensate Recovery • Operateability –Air eliminators at high points for automatic air venting – NRV installed before connecting to common condensate line • Maintenance: – Condensate pump on ground level – Bypass valve for float traps • Energy efficiency: – Condensate Recovered = 16250kg/hr – Feed Water Temperature = 105DegC – Insulated lines to minimize radiation loss – Use of APTs for optimum batch timings by prevention of stalling – Use of steam/compressed air powered pumps • Other considerations: – Manual regulation of motive steam pressure to PPPU – Use of compressed air near rice mill for PPPU – Condensate contamination to be checked manually every 30mins – Later stage automatic contamination detection system
- 10. Condensate recovery scheme Sr.No Existing Proposed Benefits 1 Condensate pumped through trap pressure Condensate to be collected in flash vessel, and pumped using PPPU Steam consumption reduced Radiation losses reduced Saving of steam loss due to venting in the feed water tank 2 Flash steam from refinery used for local heating Flash steam injected in the deaerator Increase in Feed water temperature, thus fuel saving 3 Flash steam from SEP used for local heating Flash steam to be used in process by using a Thermocompressor Saving in fuel, reduced radiation loss 4 Thermic fluid heating, changed to steam system Flash steam from driers used for Hot water tanks, condensate pumped to deaerator Saving in fuel
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- 12. Background • Five ProcessUnits – PPS 1 plant – PPS 2 plant – SPM plant – API plant – Calcium Iodate plant • Audit Recommendations – Replace Coil type boiler with Shell type – Correct steam trap selection – Condensate Recovery System
- 13. Plant schematic Boiler House SPMPlant Iodide Plant Calcium Iodate Plant PPS-1 Plant PPS-2 Plant JN Boiler 750Kg/hr @10.5Kg/cm2 g JN Boiler 750Kg/hr @10.5Kg/cm2 g FWT WHRB 480Kg/hr @10.5Kg/cm2 g PPPU PPPU PPPU PRS 480kg/hr 324kg/hr 700kg/hr 842kg/hr
- 14. Proposed system • Boilerhouse: – Replacement of Coil type boiler with a Shell Type IBR boiler – Automatic Blowdown control systems – Direct Efficiency monitoring system • Steam Distribution – PRS is located near the Boiler house to utilize existing steam pipes and avoid IBR formalities – Line sizes checked for peak steam flow, changes made wherever necessary – Air vents have been suggested for 12 locations • Steam trapping – Float traps for equipments – TD traps for Steam headers
- 15. Boiler house • Operateability: –Layout designed with space for operation and access to the boiler controls – Elevation of steam header and PRS at 0.8m – Automatic level controller for feed water tank – Chimney location near the boiler for effective exhaust of flue gases • Maintenance: – 2 meters space in front of the boiler for cleaning boiler tubes – Height of boiler shed; 6m considering the total height of; boiler + feed tank + DA head • Energy efficiency: – Efficiency monitoring system for direct efficiency and blowdown losses – Automatic blowdown control system • Future expansion: – Layout designed to accommodate the future boiler – NRV installed on the boiler outlet • Other considerations – 20D upstream and 10D downstream straight length for SFM
- 16. Steam distribution • Operateability: –All isolation valves at 1m elevation • Future expansion: – Additional nozzles provided on the steam distribution header for future connections • Maintenance: – Traps installed on side of drain pocket – Moisture separators for critical components; flow meters, control valves • Energy efficiency: – Steam lines are insulated using Rockwool for minimum radiation losses – TD traps to drain the condensate for dry steam at the point of use – Glandless piston valves for isolation, leak tight closure • Safety: – Installation of pressure and temperature gauges on steam headers – Safety valve installed downstream of PRV – Drain pockets provided to reduce water hammer and damage to pipes and fittings
- 17. Condensate Recovery • Energyefficiency: – Condensate recovery factor = 100% – Feed water temperature = 95DegC – Insulated lines to reduce radiation loss – Steam powered pumps to reduce radiation losses and quick pumping • Safety: – Condensate lines routed in trenches to prevent obstruction in the working area • Routing: – Routed on the existing pipe racks
- 18. Shell type Boiler TDTraps for steam lines Process Natural gas Live steam leakages ceased by use of glandless piston valves Radiation losses reduced by insulation Controlled Blowdown Feed Water @ 91DegC Condensate @147DegC recovered Make-up water @ 30 degC Float traps used for process applications Condensate @95 DegC Efficiency monitoring and BD control Flo w mete r Flo w met er Stack losses Air vents for steam lines Dry saturated steam to process Comparison • Present system • Proposed system Coil type Boiler Feed Tank Process Natural gas Live steam leakages through valve stem and online accessories @ 147DegC Radiation losses due to bare boiler surface Uncontrolled Blowdown Feed Water @ 80DegC Condensate @147DegC drained Stack losses Make-up water @ 30 degC Radiation losses and flashing due to bare tank surface econo miser Wet steam to process
- 19. Monitoring system efficiency Time Boiler pressure (kg/cm2g) Feed water tank temperature (degC) Make-up water quantity (Kg/day) Blowdown quantity (Kg/day) Steam consumption (Kg/day) Fuel consumption (Kg/day) S:F ratio Direct Efficiency Max Min Avg Production quantity (Ton/day) Condensate quantity (kg/day) Steam/production Ratio SPM plant PPS 1 plant PPS-2 plant Calcium Iodate plant Iodide plant Total production Pump 1 Pump 2 Pump 3 Pump 4 Total
- 20. Green field project OswalApparels Pvt. Ltd
- 21. Background • Focus area: •Steam distribution system • Compressed air system • Effluent heat recovery system • Equipments arranged in two floors • Rice husk fired boilers • MP equipments@8barg • LP equipments@3.5barg • 2 Boilers – One standby, One working – Make: Thermax – Capacity: 6TPH – Pressure: 10.5kg/cm2g – Fuel: Rice husk
- 22. Boiler house • Operateability: – Automatic Level controller for feed water tank – Main steam header placed in boiler house elevation of 1m • Energy efficiency: – Efficiency monitoring system for direct, indirect efficiency and blowdown loss • Future expansion: – Spare Nozzle for future yarn dyeing m/c. • Other considerations: – Feed water management for two feed water tanks 25KL, 15KL at elevation of 4m and 6m – Diversity factor 65%, heating rate of 2DegC/min, 7.5 TPH requirement. Boiler capacity = 6TPH, thus heating rate approx 1.5DegC/min.
- 23. Steam Generation • Maintenance: –PRS is located in Grey fabric stores at elevation of 0.8 m from ground level for ease of maintenance • Safety: – Drain pockets provided to prevent water hammer – Safety valve installed downstream of PRV • Energy efficiency: – PRS is located near the process – Insulation of steam lines – Air vents provided at terminal ends of pipes for better start-up of the plant • Layout considerations: – Lines routed along boundary wall at 4m elevation. – Cut-out for routing of pipes between two floors. – Expansion loops are provided to absorb the thermal expansion of pipes, • Other considerations: – Inlet connections to equipments at 0.7m. to be finalised during installation based on nozzle orientation – Location of tapings and elevations of inlets for equipments on HOLD to be decided during installation considering nozzle orientation – Installation of pressure and temperature gauges on steam headers
- 24. Condensate Recovery • Maintenance: –The condensate pump is placed at ground – Drain valve provided at the flash vessel intlet – Condensate lines from equipments are routed along the boundary walls on supports at 0.3m elevation • Energy efficiency: – Insulated lines to reduce radiation loss – Steam powered pumps for reduced radiation losses, quick pumping – Flash steam injected to the feed water resulting in fuel savings – Hot water generation system can be incorporated at a later stage • Other considerations: – Air eliminators installed at high points
- 25. Compressed air system •Operateability – Air receiver to accommodate the fluctuations – Air dryer to remove moisture – Closed Loop Ring type distribution system to reduce the pressure drop – Drain traps and moisture separators for removal of moisture – Pressure gauges to monitor the pressure • Other considerations: – The location of the air compressor is placed near the thermic fluid boilers at present as discussed with OAPL – Location of tapings, for equipments on hold to be decided during installation considering nozzle orientation. – Compressor, Receiver, and Air drier have to be supplied by the Compressor vendor.
- 26. Effluent heat recovery •Operateability: – Three pumps have to be installed; for present and future load, one for standby. – Two pumps for soft water pumping, one for standby – Flow switch is provided on the hot effluent line and control valve on the soft water line so that flow rate of both fluids is equal. – Overflow drain from hot effluent sump to the cold effluent sump is provided to avoid spillage. • Other considerations: – Hot effluent and cold effluent have to be separated before entering the hot effluent sump – Pumps and PHE at ground level, Hot water tank at third floor, for gravity flow to dyeing machines. – Separate hot water lines have to be provided to the dying machines by OAPL
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- 28. Steam Line sizing •Super heated steam velocity = 40m/s • Saturated steam velocity = 25m/s • Steam headers sized for 20m/s • Flash steam velocity = 15m/s • Pressure drop calculations based on pressure factor method considering equivalent length of valves and fittings • Standards: – Thickness calculation • ASME B31.1 Power plants • ASME B31.3 Process plants – IBR 1950 welding joint details – Dimension standards • ASME B36.10 for Carbon steel • ASME B36.19 for SS pipe • IS 1239 & IS 3589 for ERW pipes
- 29. Example – Linesizing LINE NO. FROM TO FLOW RATE (kg/hr) PRESSURE (kg/cm2g) DIA (NB) Le (m) Pr DROP (kg/cm2g) MPST-100-SMLS-205-IH MP HDR REFINERY 3000 10 100 141.35 0.22 SP VOL. ID PIPE LENGTH ELBOWS VALVES OTHER TOTAL Qty Le Qty Le 0.182 87.87 42 4 13.5 2 73 10% 141.35
- 30. Good engineering practices •PRS location near point of use • PRS and Steam headers at elevations of approx 1m • Slope of 2mm per meter for steam lines • Drain pockets at terminal ends • Air vents, temperature and pressure gauges on steam headers • Moisture separators installed upstream of steam flow meters, and control valves • Use of eccentric reducers, flat bottom • Strainers installed with the arm oriented horizontally • Pipe bridge crossing roads at 6.5m elevation • 20D upstream and 10D downstream straight length for flow meters • Expansion loops on straight pipe runs of 30m
- 31. Steam traps Steam trapsselection • Float traps for equipments – Selection criteria • Condensate load • Back pressure • Inlet pressure • TD trap module for steam lines – Selection criteria • Condensate load • Back pressure • Inlet pressure • APT for Drying equipments – Condensate load – Back pressure – Motive steam pressure – Inlet pressure • Back pressure = Static head (10m = 1bar) + friction head + equipment pressure(0.12 for deaerator)
- 32. • Condensate Linesizing: • Drain lines to the pump receiver – 2 x condensate load to account for chances of bi-phase flow – Pressure drop of 0.8mbar/meter • Pumped condensate lines – 6 x condensate load – Pressure drop of 0.8mbar/meter – Verified by Moody’s Friction factor method • Good engineering practices – Air eliminators at high points – NRV before connecting to common condensate line – Drain valve at inlet of flash vessel
- 33. Example LINE NO. FROMTO FLOW RATE (kg/hr) PRESSURE (kg/cm2g) DIA (NB) Le (m) Pr DROP (kg/cm2) Water chart 0.8mbar/m COND-80-ERW-401 CP 2 DA 3280 8.7 80 225 0.12 0.18 PIPE LENGTH ELBOWS VALVES OTHER TOTAL NOS Le NOS. Le 171.3 5 8 1 25 10% 225 f - FRICTION FACTOR 0.0211 Re = ρ x V x D µ Hf = f x L x V2 2 x g x D f = Moody’s Friction factor Based on the graph e/D ratio Re – Reynolds no. e – Pipe roughness factor 0.045mm for commercial pipes 0.015mm for seamless pipes ρ – Density = 1000kg/m3 µ - Kinematic viscosity = 1 x 10-6 m2/s
- 34. Equipment selection • Condensatepumps – Selection criteria • Condensate load • Motive steam pressure • Back pressure • Flash vessel – Selection criteria • Inlet pressure • Flash pressure • Condensate load
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