(53f) Retrofitting An Existing Methanol Product Process Using Fundamental Process Synthesis Tools

Fundamental tools to determine the most efficient structures of processes, optimization of process sections, reducing emissions and identify efficient ways to operating processes have been previously developed (Patel et al, 2007; Baraka et al, 2010). Retrofitting is a term used in chemical engineering to define updating the outdated. Retrofitting is applied on the improvement of flow-sheets, process equipment and chemical processes.

This investigation evaluates ways in which these tools can be utilized to analyze and retrofit an existing methanol production process. The process synthesis tool utilizes physical and thermodynamic principles to set targets.  The targets provide insight to the mass, energy and entropy flows of the methanol production process. These targets can be compared to the actual flows, thus allowing for opportunities for improve process efficiency and providing insight for process integration.

Initially, we consider the overall mass balance for the process. The mass balance gives one a good indication of the overall carbon efficiency of the process. This overall mass balance is fixed, and also sets the heat and work requirements of the overall process. We can compare this overall mass balance, with the target mass balance. The next step is to look at the process sections i.e. syngas production and synthesis section. The amount of heat and work that is required by the sections is governed by the thermodynamic performance of these sections and the process integration between both sections. Again, these can be compared to the target values. This allows one to determine how efficient the process is and also determine the amount of lost work from each section. One can also compare the utility requirements for the process

The mass, heat and work flows in a process can be a complicated and often difficult to untangle the effects of these flows on the process efficiency. Using the novel tools, makes process analysis easier and more effective in making decisions in the early stages of design and also in retrofitting existing chemical processes.