Evaporator Optimization Project Bryan Picou James Roberts Advisor
Evaporator Optimization Project Bryan Picou James Roberts Advisor: Dr. Junkun Ma ET 494 Instructor : Dr. Cris Koutsougeras
Domino Sugar �Refinery is in Arabi, La �Produce 8 million pounds of sugar per day on average �It is the third largest sugar refinery in the world
Evaporator Optimization Project �Steam is one of the most expensive resources for a refinery �Take the current operation of the evaporators and make it more efficient �Take the current operation of the melters and eliminate the steam
Evaporators �Evaporator uses steam in a vacuum to heat the sugar liquor and lower its density �Left over vapors from this process is what we are trying to optimize
Melter �Takes the raw sugar and uses steam to melt this sugar into a liquid. �It uses direct steam injection �Vapors from evaporator will be rerouted to power the melter
Current Operation
Current Operation
Sugar Parameters �Based upon 8 million pound melt rate � 8 % scrap rate �Sugar going into melters assuming 70 Brix
Sketch of Phase 1
Energy required to Melt Sugar Q= Specific Heat * Mass of Sugar * ΔTemperature Q=0. 65 BTU/lb F * 478, 800 lb/hr * (165 F-130 F) Q=10, 892, 700 Btu/hr
Barometric Condenser
Condenser Design �Qsteam = Qsugar �Mass of Steam * Latent Heat of Steam = Cp of Sugar * Mass of Sugar * ΔTemperature �Rearranging: �Mass Steam = (Cp of Sugar * Mass of Sugar * Δtemperature)/Latent Heat of Steam
Steam With Phase Change �Qsugar = Mass of Steam * Latent Heat of Steam � 10, 892, 700 BTU/hr = m * 922. 6 BTU/lb �Mass of Steam = 11, 806. 525 lb/hr
Sugar going to Condenser �Q steam = Mass * Specific Heat * Δ Temperature � 10, 892, 700 BTU/hr = m * 0. 65 BTU/lb F * (188. 421 F – 165 F) �M = 715, 511. 72 lb/hr �M = 1079. 6 gpm
Steam Pipeline Head loss �HL = f * (L/D) * (V 2/2 g) �HL = 0. 015 * (341/24) * (67. 512/2*32. 2) �HL = 180. 97
Steam Pipeline Design Babcock Formula �Δp = 0. 47 * (d+3. 6/d^6) * m^2 * L * v �Δp = 0. 47 * (24+3. 6/24^6) * 4. 436^2 * 522 * 42. 16 �Δp = 0. 0294 psia �Δp = 0. 33%
Steam Pipeline Mach Number �Mach Number = Velocity / Sonic Velocity �Mach Number = 84. 5 ft/s / 1528. 09 ft/s Mach Number = 0. 056
24” Steam Pipeline �Velocity = Volumetric flow Rate / Cross-Sectional Area of pipe �V in = 763, 077. 9 ft^3/hr / 3. 14 ft^2 �V in = 67. 51 ft/s �V out = 766, 173 ft^3/hr / 3. 14 ft^2 �V out = 84. 5 ft/s
Sugar Pipeline Design �Volumetric Flow Rate = Velocity * Area �Velocity = Volumetric Flow Rate/Area �Volumetric Flow Rate of Sugar = 150, 949. 436 * (1/92. 2) = 1637. 196 ft 3/hr �Area of 4 in pipe = 0. 0872 ft 2 �Velocity = 5. 214 ft/s
Residence Time �λ= Volume of Melter / Volumetric Flow Rate �Volume of Melter = 329. 867 ft 3 �Volumetric Flow Rate = 2884. 34 ft 3/hr �λ= 6. 86 min
Residence Time �Residence Time with South Melter �λ= 10. 29 min
Sugar Dissolution Lab Sugar Dissolution 200 R 2 = 0. 9394 180 160 Temperature (F) 140 120 100 Temp (°F) Power(Temp (°F)) 80 60 40 20 0 0 5 10 15 20 25 Time (min) 30 35 40 45
Adding a Melter the same size �Theoretical Temperature = 246. 75 * x-0. 173 �Theoretical Temperature = 246. 75 * 13. 72 -0. 173 �Theoretical Temperature = 156. 85 F
Residence Time with New Melter �λ= 13. 72 min �This extra melter would give the sugar an extra 33. 24% more residence time than theoretically needed
Heat Exchangers �Δp in HX#1 to HX#2 = Inlet from G 5 pump – Inlet of HX #2 �Δp in HX#1 to HX#2 = 47. 39 psia – 41. 39 psia �Δp in HX#1 to HX#2 = 6 psia �Approach Temperature
3 Pumps �P 1/γ 1 + Z 1 + V 12/2 g – h. L + h. A = P 2/γ 2 + Z 2 + V 22/2 g �Condenser Pump �h. L = 2. 48 ft �h. A = 10 psia
Pipelines �V = Q/A �Melter Recirculation Pipeline (8”) �V = 8659. 33 ft^3 / (0. 349 *3600) �V = 6. 89 ft/sec
Steam Pipeline Supports �F = E * I * π^2 / K * L^2 �F = 29000000 psi * 28. 09 in^4 * π^2 / 2 * 420^2 in^2 �F = 22, 788. 8 lb
Deflection �Y = W * L^3/ 3 * E * I �Deflection of I beam �Y = 1904. 26 lb * 20^3 in ^3/ 3 * 29000000 psi * 127. 7 in^4 �Y = 0. 00137 in
Bolts (5/8”) �σ = F/A �σ = 9427 psi/4 Bolts �σ = 2356. 7 psi / Bolt
Clevis Hangers �σ = F/πr^2 � 24” Steam Pipeline �R = 1904. 26 / π * 18000 �R = 0. 183 in �Diameter = 0. 367 in
Condenser Supports (Stress) �σ = W * L / Z �σ = 17, 314 lb * 109 in / 91. 3 in^4 �σ = 20, 671. 79 psi
Thermal Expansion �ΔL = Lo * α * ΔT �Steam Pipeline �ΔL = 3. 96 in
Evaporators �Msi Lsi + MLi LLi = Mso Lso + Mso Lso � 4 A Evaporator Msi = (11. 81 * 1141. 4)+(476. 35*107. 5)(488. 16*104. 8)/949. 7 �Msi = 14. 24 kpph �
Evaporators �Density of Liquor Exiting = Mass of Feed liquor * Density of Feed Liquor / Mass of Exiting Liquor �Density = 488. 16 kpph * 64. 4 Brix / 476. 35 kpph �Density = 65. 996 Brix
Evaporators �Exiting Temperature of Liquor = Boiling Point Rise + Steam Temperature �Exiting Temperature = 7. 056 + 188. 58 �Exiting Temperature = 195. 64 F
Phase 2
Heat Exchanger �Q = U *A * ΔTLM �UA = Q * ΔTLM �Current Operation �UA = 149, 103. 6 �Evaporator Optimization Project �UA = 149, 943. 9
Savings �Phase 1 �$/year = (12, 000 lb/hr * 986. 2 BTU/lb / 79. 5% Boiler Efficiency) * 24 hrs * ($3. 73/1, 000 BTU) * 260 days �$/year = 346, 734. 88
Savings �Phase 2 �$/year = (2, 600 lb/hr * 949. 6 BTU/lb / 79. 5% Boiler Efficiency) * 24 hrs * ($3. 73/1, 000 BTU) * 260 days �$/year = 72, 283. 70
Savings �Combined �$/year = 419, 072. 69
Prices �Phase 1 �Total Cost = $1, 205, 105. 29 (+/- 15%) �Phase 2 �Total Cost = $221, 429. 38 (+/- 15%) �Combined �Total Cost = $1, 426, 534. 67 (+/- 15%)
Return on Investment �Phase 1 �ROI = 3. 48 years �Phase 2 �ROI = 3. 06 years �Combined �ROI = 3. 41 years
Further Research �Eliminating Steam to Saturators
Final Proposal
References �Domino Sugar Corporation �Cane Sugar Refining Handbook �www. sugartech. co. za
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