《化学工程设计技术》课程教学资源（参考资料，英文版）14 Design 1 Choice of Process Type（revised）

DESIGN METHODOLOGY CHOICE OF PROCESS TYPE GOAL-- Choose the process type appropriate to the plant to be designed 1/31/99 Choice of Process Type

1/31/99 Choice of Process Type 1 DESIGN METHODOLOGY: CHOICE OF PROCESS TYPE GOAL -- Choose the process type appropriate to the plant to be designed

MAJOR PROCESS TYPES CONTINUOUS STEADY-STATE E Used for world-scale production of commodity chemicals E Large, centrally located plants ◆ BATCH E Used for small-scale production of high value-added chemicals ◆ JIT MINIPLANT E Used for on-site production of hazardous or difficult to transport chemicals Continuous Steady-State is the dominant process type 1/31/99 Choice of Process Type

1/31/99 Choice of Process Type 2 MAJOR PROCESS TYPES uCONTINUOUS STEADY-STATE ð Used for world-scale production of commodity chemicals ð Large, centrally located plants uBATCH ð Used for small-scale production of high value-added chemicals uJIT MINIPLANT ð Used for on-site production of hazardous or difficult to transport chemicals Continuous Steady-State is the dominant process type

CONTINUOUS STEADY-STATE (Continuous Steady State) ◆ WHEN USED E Large scale production(50-1000 MM Kgly E Mostly for vapor/liquid processes ◆ADⅤ ANTAGES E Low cost of production through economy of scale E Allows on-site support infrastructure ◆ DISADⅤ NTAGES E Large plant s often located in environmentally sensitive areas E Require storage and transportation of hazardous chemicals E large on-site inventories of hazardous materials E Emissions control a problem 1/31/99 Choice of Process Type

1/31/99 Choice of Process Type 3 CONTINUOUS STEADY-STATE (Continuous Steady State) uWHEN USED ð Large scale production (50 - 1000 MM Kg/yr) ð Mostly for vapor/liquid processes uADVANTAGES ð Low cost of production through economy of scale ð Allows on-site support infrastructure uDISADVANTAGES ð Large plant s often located in environmentally sensitive areas ð Require storage and transportation of hazardous chemicals ð Large on-site inventories of hazardous materials ð Emissions control a problem

BATCH ◆ WHEN USED E Small scale production(1-10, 000, 000 Kg/yr) E Fouling materials E Recipe driven process technology ◆ ADVANTAGES E Flexibility of operation 口 Multiple product slates E Maintenance of sterile conditions for bioprocessing ◆ DISADVANTAGES → Labor intensive E High cost of production E Complex operations High inventories 1/31/99 Choice of Process Type

1/31/99 Choice of Process Type 4 BATCH uWHEN USED ð Small scale production (1 - 10,000,000 Kg/yr) ð Fouling materials ð Recipe driven process technology uADVANTAGES ð Flexibility of operation ð Multiple product slates ð Maintenance of sterile conditions for bioprocessing uDISADVANTAGES ð Labor intensive ð High cost of production ð Complex operations ð High inventories

JIT MINIPLANTS ◆ WHEN USED E Intermediate scale production (1000-1,000,000 Kg/yr) E On-site manufacture of hazardous or difficult to transport materials E Steady-state continuous operation ◆ADⅤ ANTAGES E Minimal transportation and storage of hazardous materials E Tight control of emissions ◆ DISADⅤ ANTAGES E Loss ofeconomy of scale E Design methodology new and relatively untested E Operation by non-expert personnel 1/31/99 Choice of Process Type 5

1/31/99 Choice of Process Type 5 JIT MINIPLANTS uWHEN USED ð Intermediate scale production (1000 - 1,000,000 Kg/yr) ð On-site manufacture of hazardous or difficult to transport materials ð Steady-state continuous operation uADVANTAGES ð Minimal transportation and storage of hazardous materials ð Tight control of emissions uDISADVANTAGES ð Loss of economy of scale ð Design methodology new and relatively untested ð Operation by non-expert personnel