DESIGN METHODOLOGY ILA INPUT-OUTPUT DECISIONS GOAL- Choose the process chemistry and feedstock most appropriate to the plant to be designed and determine the associated economic potential 1l/19/99 Input-Output Structure
11/19/99 Input-Output Structure 1 DESIGN METHODOLOGY II: INPUT-OUTPUT DECISIONS GOAL -- Choose the process chemistry and feedstock most appropriate to the plant to be designed and determine the associated economic potential
BASIC LEVEL II DECISIONS o Choice of reaction chemistry o Choice of raw material feedstocks o Determination of need for vapor recycle Evaluation ofeconomic potential for process 1l/19/99 Input-Output Structure
11/19/99 Input-Output Structure 2 BASIC LEVEL II DECISIONS u Choice of reaction chemistry u Choice of raw material feedstocks u Determination of need for vapor recycle u Evaluation of economic potential for process
CHOICE OF REACTION CHEMISTRY The choice of reaction chemistry involves the following considerations o Source of the chemistry to be employed E Developed in-house E Freely available patents expired) E Available only through a license ◆ Availability offeed stocks ◆ Choice ofprocess type Environmental considerations 1l/19/99 Input-Output Structure
11/19/99 Input-Output Structure 3 CHOICE OF REACTION CHEMISTRY The choice of reaction chemistry involves the following considerations: u Source of the chemistry to be employed ð Developed in-house ð Freely available (patents expired) ð Available only through a license u Availability of feed stocks u Choice of process type u Environmental considerations
EXAMPLE #1 Chemistries available to manufacture vinyl chloride ffrom Seider et al, Process Design Principles) 9 Direct chlorination of ethylene C2H4+Cl2-> C2H3Cl+ HCl (Only half the cl2 converted to vinyl chloride Thermal cracking of dichloroethane via Oxychlorination of ethyelene CH4+2HCl+1202-C2H4C12+H20 C2H4C12 -->C2H3C+HCl (Uses HCl instead of cl2, but requires two reaction steps) 1l/19/99 Input-Output Structure
11/19/99 Input-Output Structure 4 EXAMPLE #1 Chemistries available to manufacture Vinyl chloride (from Seider et al, Process Design Principles) uDirect chlorination of Ethylene C2H4 + Cl2 --> C2H3Cl + HCl (Only half the Cl2 converted to vinyl chloride) u Thermal cracking of Dichloroethane via Oxychlorination of Ethyelene C2H4 + 2HCl + 1/2 O2 --> C2H4Cl2 + H2O C2H4Cl2 --> C2H3Cl + HCl (Uses HCl instead of Cl2, but requires two reaction steps)
EXAMPLE #1(Contd.) o Balanced process for Chlorination ofof ethylene C2H4+C2->C2H4C2 CH4+2HC+1202->C2H4C2+H20 2 C2H4012->2 C2H3C +2 HC Converts all cl atoms to vinyl chloride 1l/19/99 Input-Output Structure 5
11/19/99 Input-Output Structure 5 EXAMPLE #1 (Cont’d.) u Balanced Process for Chlorination of of Ethylene C2H4 + Cl2 --> C2H4Cl2 C2H4 + 2HCl + 1/2 O2 --> C2H4Cl2 + H2O 2 C2H4Cl2 --> 2 C2H3Cl +2 HCl (Converts all Cl atoms to Vinyl Chloride)