CHEMCAD Seminar Heat Transfer John Edwards, P&I Design Ltd January, 2015

1. CHEMCAD Seminar Heat Transfer John Edwards, P&I Design Ltd January, 2015 www.chemstations.com

2. CRYOGENIC BATCH REACTOR OPTIMISATION HEAT TRANSFERSESSION OBJECTIVES • Design procedure for shell and tube heat exchanger sizing • Design parameters review • TEMA layouts • Heat exchanger performance and fouling rating • Consider sensible heat and phase change heat exchangers • Design Margin and Fouling www.chemstations.com www.chemstations.net www.chemcad.co.uk

3. CRYOGENIC BATCH REACTOR OPTIMISATION HEAT TRANSFERBASIC THEORY Section 7 page 229 www.chemstations.com www.chemstations.net www.chemcad.co.uk

4. CRYOGENIC BATCH REACTOR OPTIMISATION HEAT TRANSFERDESIGN PARAMETERS Section 7 page 259, Simulation Cases Process Process fluid assignments to shell side or tube side. Selection of stream temperature specifications. Setting shell side and tube side pressure drop design limits. Setting shell side and tube side velocity limits. Selection of heat transfer models and fouling coefficients for shell and tube side. Mechanical Selection of heat exchanger TEMA layout and number of passes. Specification of tube parameters - size, layout, pitch and material. Setting upper and lower design limits on tube length. Specification of shell parameters – materials, baffle cut, baffle spacing and clearances. Setting upper and lower design limits on shell diameter, baffle cut and baffle spacing. www.chemstations.com www.chemstations.net www.chemcad.co.uk

5. CRYOGENIC BATCH REACTOR OPTIMISATION HEAT TRANSFERSHELL AND TUBE TEMA LAYOUTS Section 7 page 245, Appendix IV www.chemstations.com www.chemstations.net www.chemcad.co.uk

6. CRYOGENIC BATCH REACTOR OPTIMISATION HEAT TRANSFERMODEL SELECTION FLOW CHART Section 7 page 258, Appendix XIV www.chemstations.com www.chemstations.net www.chemcad.co.uk

7. CRYOGENIC BATCH REACTOR OPTIMISATION HEAT TRANSFER TUBE OR SHELL SIDE FLUID SELECTION Process fluid assignments to shell side or tube side? Tube side Expensive material of construction High pressures High fouling potential Shell side High volume flow rates High viscosity Heat exchangers for high fouling and high viscosity fluids Shell and Tube Heat Exchanger Designs Shell side Helical flow baffles by Lummus No low velocity zones or bypass flows Tube side Twisted tubes by Brown Fintube Co Increase shear Spiral heat exchanger Plate and frame Plate and Shell www.chemstations.com www.chemstations.net www.chemcad.co.uk

8. CRYOGENIC BATCH REACTOR OPTIMISATION HEAT TRANSFERCASE 7.04 METHANOL COOLING Section 7 page 270, Case 7.04 Cool 100000 kg/h methanol from 95 to 40°C Coolant brackish water at 25°C maximum return 40°C Calculated duty 4364 kW water flow required 250000 kg/h Methanol on shell side being the cleanest fluid Fouling coefficients 0.00035 m2°K/W Tube side pass 2 Shell side pass 1 www.chemstations.com www.chemstations.net www.chemcad.co.uk

9. CRYOGENIC BATCH REACTOR OPTIMISATION HEAT TRANSFERCASE 7.01 HORIZONTAL CONDENSOR Section 7 page 260, Case 7.01 www.chemstations.com www.chemstations.net www.chemcad.co.uk

10. CRYOGENIC BATCH REACTOR OPTIMISATION HEAT TRANSFERCASE 7.07 EVAPORATIVE COOLING TOWER Section 7 page xxx, Case 7.07 (Edition 3) A distillation column overhead condenser has a duty of 2740 kW The condenser design is based on OHTC 50 Btu/h-ft2-°C with HTA 1700 ft2 Cooling water at 102°F is recirculated at 19850 kg/h through a fin fan cooler The tower is simulated using SCDS column in VLE mode with 2 stages Heat removal is simulated using heat exchanger 120 Btu/h-ft2-°C with HTA 3280 ft2 Inlet air flow is 193523 stdV m3/h and humidity is set. Murphree η adjusted to process www.chemstations.com www.chemstations.net www.chemcad.co.uk

11. CRYOGENIC BATCH REACTOR OPTIMISATION HEAT TRANSFERCASE 7.08 GAS COMPRESSION STATION Section 7 page xxx, Case 7.08 (Edition 3) Natural gas is compressed from 43 bar at 10°C to 87.2 bar at 72°C A fin fan air after cooler reduces the temperature to 50°C The cooler has 1 bay with 2 fans and 2 single pass coils in series with 4 rows The gas flow is 283176 kg/h with MW 18.5 kg/kmol Air inlet temperature 30°C and outlet temperature 46.2°C at 111.7 Pa Mechanical details are entered into the Air Cooler Sizing Tool in Rating Mode www.chemstations.com www.chemstations.net www.chemcad.co.uk

12. CRYOGENIC BATCH REACTOR OPTIMISATION HEAT TRANSFERCASE 7.09 BITUMEN HEAT EXCHANGER Section 7 page xxx, Case 7.09 (Edition 3) Design a heat exchanger for 100 te/h bitumen at 140° to be heated to 170°C Heating fluid Therminol HTO at 270°C with a return temperature of 250°C Bitumen on the shell side due to high viscosity Tubes are 1” od with a square pitch of 1.25” Maximum tube length allowed set at 3 m with no excess design Fouling tube side 0.0001761 W/m2-°K and shell side 0.001761 W/m2-°K www.chemstations.com www.chemstations.net www.chemcad.co.uk

13. CRYOGENIC BATCH REACTOR OPTIMISATION HEAT TRANSFERCASE 7.10 DOUBLE EFFECT EVAPORATOR Section 7 page xxx, Case 7.10 (Edition 3) An acetone, water and methyl oleate process stream is separated in a double effect falling film evaporator. The process stream is fed to the second effect in a backward feed mode and the heat input is supplied by steam at 7 bar to the first effect. www.chemstations.com www.chemstations.net www.chemcad.co.uk