Utilities & Energy Integration interview questions

1. A.temperature where hot and cold composite curves are ΔTmin apart; no heat should cross it, no cold utility above it and no hot utility below it
2. B.hot and cold stream enthalpy-temperature curves overlaid; their closest vertical approach is the pinch and the overhangs give minimum hot and cold utility
3. C.plot of net heat flow against shifted temperature used to place utilities such as steam levels, furnaces and refrigeration at the right temperatures
4. D.back-pressure turbine that generates power while letting steam down from HP to process headers, far more efficient than PRV letdown

Answer + AI explanation with Pro

1. A.Heat exchanger network design
2. B.Composite curves
3. C.Cooling water system
4. D.Pinch point

Answer + AI explanation with Pro

1. A.Composite curves — hot and cold stream enthalpy-temperature curves overlaid; their closest vertical approach is the pinch and the overhangs give minimum hot and cold utility
2. B.Composite curves — typical plant headers of HP (about 40 bar), MP (about 10 bar) and LP (about 3.5 bar), let down through turbines or PRV-desuperheater stations
3. C.Composite curves — temperature where hot and cold composite curves are ΔTmin apart; no heat should cross it, no cold utility above it and no hot utility below it
4. D.Composite curves — matching hot and cold streams starting at the pinch with CP rules (CP_hot ≤ CP_cold above pinch) and the N−1 minimum-units target

Answer + AI explanation with Pro

1. A.matching hot and cold streams starting at the pinch with CP rules (CP_hot ≤ CP_cold above pinch) and the N−1 minimum-units target
2. B.plot of net heat flow against shifted temperature used to place utilities such as steam levels, furnaces and refrigeration at the right temperatures
3. C.hot and cold stream enthalpy-temperature curves overlaid; their closest vertical approach is the pinch and the overhangs give minimum hot and cold utility
4. D.temperature where hot and cold composite curves are ΔTmin apart; no heat should cross it, no cold utility above it and no hot utility below it

Answer + AI explanation with Pro

1. A.Steam levels
2. B.ΔTmin trade-off
3. C.Pinch point
4. D.Refrigeration cascade

Answer + AI explanation with Pro

1. A.Pinch point — temperature where hot and cold composite curves are ΔTmin apart; no heat should cross it, no cold utility above it and no hot utility below it
2. B.Pinch point — plot of net heat flow against shifted temperature used to place utilities such as steam levels, furnaces and refrigeration at the right temperatures
3. C.Pinch point — back-pressure turbine that generates power while letting steam down from HP to process headers, far more efficient than PRV letdown
4. D.Pinch point — matching hot and cold streams starting at the pinch with CP rules (CP_hot ≤ CP_cold above pinch) and the N−1 minimum-units target

Answer + AI explanation with Pro

1. A.hot and cold stream enthalpy-temperature curves overlaid; their closest vertical approach is the pinch and the overhangs give minimum hot and cold utility
2. B.temperature where hot and cold composite curves are ΔTmin apart; no heat should cross it, no cold utility above it and no hot utility below it
3. C.recirculating tower giving about 33 °C supply and 10 °C range, with cycles of concentration limited by silica and hardness and controlled by blowdown and biocide
4. D.typical plant headers of HP (about 40 bar), MP (about 10 bar) and LP (about 3.5 bar), let down through turbines or PRV-desuperheater stations

Answer + AI explanation with Pro

1. A.Composite curves
2. B.Steam levels
3. C.Cogeneration
4. D.ΔTmin trade-off

Answer + AI explanation with Pro

1. A.Steam levels — recirculating tower giving about 33 °C supply and 10 °C range, with cycles of concentration limited by silica and hardness and controlled by blowdown and biocide
2. B.Steam levels — typical plant headers of HP (about 40 bar), MP (about 10 bar) and LP (about 3.5 bar), let down through turbines or PRV-desuperheater stations
3. C.Steam levels — smaller minimum approach saves utility but raises exchanger area; supertargeting picks the value that minimises total annual cost
4. D.Steam levels — hot and cold stream enthalpy-temperature curves overlaid; their closest vertical approach is the pinch and the overhangs give minimum hot and cold utility

Answer + AI explanation with Pro

1. A.plot of net heat flow against shifted temperature used to place utilities such as steam levels, furnaces and refrigeration at the right temperatures
2. B.temperature where hot and cold composite curves are ΔTmin apart; no heat should cross it, no cold utility above it and no hot utility below it
3. C.smaller minimum approach saves utility but raises exchanger area; supertargeting picks the value that minimises total annual cost
4. D.matching hot and cold streams starting at the pinch with CP rules (CP_hot ≤ CP_cold above pinch) and the N−1 minimum-units target

Answer + AI explanation with Pro

1. A.Refrigeration cascade
2. B.Grand composite curve
3. C.Composite curves
4. D.Cooling water system

Answer + AI explanation with Pro

1. A.Grand composite curve — plot of net heat flow against shifted temperature used to place utilities such as steam levels, furnaces and refrigeration at the right temperatures
2. B.Grand composite curve — hot and cold stream enthalpy-temperature curves overlaid; their closest vertical approach is the pinch and the overhangs give minimum hot and cold utility
3. C.Grand composite curve — back-pressure turbine that generates power while letting steam down from HP to process headers, far more efficient than PRV letdown
4. D.Grand composite curve — temperature where hot and cold composite curves are ΔTmin apart; no heat should cross it, no cold utility above it and no hot utility below it

Answer + AI explanation with Pro

1. A.typical plant headers of HP (about 40 bar), MP (about 10 bar) and LP (about 3.5 bar), let down through turbines or PRV-desuperheater stations
2. B.two refrigerants in series, such as propane then ethylene, because one fluid cannot span from −100 °C to ambient at reasonable pressures
3. C.recirculating tower giving about 33 °C supply and 10 °C range, with cycles of concentration limited by silica and hardness and controlled by blowdown and biocide
4. D.matching hot and cold streams starting at the pinch with CP rules (CP_hot ≤ CP_cold above pinch) and the N−1 minimum-units target

Answer + AI explanation with Pro

1. A.Composite curves
2. B.Refrigeration cascade
3. C.Heat exchanger network design
4. D.Cooling water system

Answer + AI explanation with Pro

1. A.Heat exchanger network design — temperature where hot and cold composite curves are ΔTmin apart; no heat should cross it, no cold utility above it and no hot utility below it
2. B.Heat exchanger network design — typical plant headers of HP (about 40 bar), MP (about 10 bar) and LP (about 3.5 bar), let down through turbines or PRV-desuperheater stations
3. C.Heat exchanger network design — back-pressure turbine that generates power while letting steam down from HP to process headers, far more efficient than PRV letdown
4. D.Heat exchanger network design — matching hot and cold streams starting at the pinch with CP rules (CP_hot ≤ CP_cold above pinch) and the N−1 minimum-units target

Answer + AI explanation with Pro

1. A.matching hot and cold streams starting at the pinch with CP rules (CP_hot ≤ CP_cold above pinch) and the N−1 minimum-units target
2. B.hot and cold stream enthalpy-temperature curves overlaid; their closest vertical approach is the pinch and the overhangs give minimum hot and cold utility
3. C.smaller minimum approach saves utility but raises exchanger area; supertargeting picks the value that minimises total annual cost
4. D.recirculating tower giving about 33 °C supply and 10 °C range, with cycles of concentration limited by silica and hardness and controlled by blowdown and biocide

Answer + AI explanation with Pro

1. A.Cooling water system
2. B.ΔTmin trade-off
3. C.Grand composite curve
4. D.Cogeneration

Answer + AI explanation with Pro

1. A.Cooling water system — smaller minimum approach saves utility but raises exchanger area; supertargeting picks the value that minimises total annual cost
2. B.Cooling water system — plot of net heat flow against shifted temperature used to place utilities such as steam levels, furnaces and refrigeration at the right temperatures
3. C.Cooling water system — back-pressure turbine that generates power while letting steam down from HP to process headers, far more efficient than PRV letdown
4. D.Cooling water system — recirculating tower giving about 33 °C supply and 10 °C range, with cycles of concentration limited by silica and hardness and controlled by blowdown and biocide

Answer + AI explanation with Pro

1. A.matching hot and cold streams starting at the pinch with CP rules (CP_hot ≤ CP_cold above pinch) and the N−1 minimum-units target
2. B.smaller minimum approach saves utility but raises exchanger area; supertargeting picks the value that minimises total annual cost
3. C.plot of net heat flow against shifted temperature used to place utilities such as steam levels, furnaces and refrigeration at the right temperatures
4. D.back-pressure turbine that generates power while letting steam down from HP to process headers, far more efficient than PRV letdown

Answer + AI explanation with Pro

1. A.Pinch point
2. B.Heat exchanger network design
3. C.Steam levels
4. D.Cogeneration

Answer + AI explanation with Pro

1. A.Cogeneration — matching hot and cold streams starting at the pinch with CP rules (CP_hot ≤ CP_cold above pinch) and the N−1 minimum-units target
2. B.Cogeneration — recirculating tower giving about 33 °C supply and 10 °C range, with cycles of concentration limited by silica and hardness and controlled by blowdown and biocide
3. C.Cogeneration — typical plant headers of HP (about 40 bar), MP (about 10 bar) and LP (about 3.5 bar), let down through turbines or PRV-desuperheater stations
4. D.Cogeneration — back-pressure turbine that generates power while letting steam down from HP to process headers, far more efficient than PRV letdown

Answer + AI explanation with Pro

1. A.recirculating tower giving about 33 °C supply and 10 °C range, with cycles of concentration limited by silica and hardness and controlled by blowdown and biocide
2. B.temperature where hot and cold composite curves are ΔTmin apart; no heat should cross it, no cold utility above it and no hot utility below it
3. C.plot of net heat flow against shifted temperature used to place utilities such as steam levels, furnaces and refrigeration at the right temperatures
4. D.smaller minimum approach saves utility but raises exchanger area; supertargeting picks the value that minimises total annual cost

Answer + AI explanation with Pro

1. A.Composite curves
2. B.Pinch point
3. C.Steam levels
4. D.ΔTmin trade-off

Answer + AI explanation with Pro

1. A.ΔTmin trade-off — smaller minimum approach saves utility but raises exchanger area; supertargeting picks the value that minimises total annual cost
2. B.ΔTmin trade-off — matching hot and cold streams starting at the pinch with CP rules (CP_hot ≤ CP_cold above pinch) and the N−1 minimum-units target
3. C.ΔTmin trade-off — temperature where hot and cold composite curves are ΔTmin apart; no heat should cross it, no cold utility above it and no hot utility below it
4. D.ΔTmin trade-off — back-pressure turbine that generates power while letting steam down from HP to process headers, far more efficient than PRV letdown

Answer + AI explanation with Pro

1. A.typical plant headers of HP (about 40 bar), MP (about 10 bar) and LP (about 3.5 bar), let down through turbines or PRV-desuperheater stations
2. B.plot of net heat flow against shifted temperature used to place utilities such as steam levels, furnaces and refrigeration at the right temperatures
3. C.two refrigerants in series, such as propane then ethylene, because one fluid cannot span from −100 °C to ambient at reasonable pressures
4. D.temperature where hot and cold composite curves are ΔTmin apart; no heat should cross it, no cold utility above it and no hot utility below it

Answer + AI explanation with Pro

1. A.Steam levels
2. B.Pinch point
3. C.Composite curves
4. D.Refrigeration cascade

Answer + AI explanation with Pro

1. A.Refrigeration cascade — smaller minimum approach saves utility but raises exchanger area; supertargeting picks the value that minimises total annual cost
2. B.Refrigeration cascade — hot and cold stream enthalpy-temperature curves overlaid; their closest vertical approach is the pinch and the overhangs give minimum hot and cold utility
3. C.Refrigeration cascade — two refrigerants in series, such as propane then ethylene, because one fluid cannot span from −100 °C to ambient at reasonable pressures
4. D.Refrigeration cascade — plot of net heat flow against shifted temperature used to place utilities such as steam levels, furnaces and refrigeration at the right temperatures

Answer + AI explanation with Pro