(53d) A Graphical Approach to Flow Sheet Synthesis as Applied to the Fischer-Tropsch System

In this paper a novel approach to flow sheet synthesis is applied to the design of a flow sheet for the production of Fischer-Tropsch hydrocarbons. This graphical technique, called the GH-space, uses the flows of heat and work inside a process to provide insight into the interactions of various process units from the very beginning of a design. 

Any unit process can be represented as a vector on the GH-space. By manipulating these vectors a process can be designed to meet certain design criteria or constraints.

In this paper five independent mass balances (reactions) were defined. These were then used; together with vectors describing mixing, separation and pressure; to determine the overall mass, energy and work balances for the process before any flow sheet existed. These overall balances were then used to begin formulating the flow sheet.

It was shown that with careful manipulation of design variables a process could be designed that not only produced the desired product but also consumed Carbon Dioxide as a feed and could potentially generate electricity.

While the GH-space technique is dynamic and flexible it tends towards the “best” thermodynamic solution. While it may not always be possible in a practical sense it allows a basis for more detailed design or for the modification of existing flow sheets.