Continuous Co-Separation by Liquid Absorption in Aqueous Cuprous Chloride (CuCl) and Magnesium Chloride (MgCl2) Solution Continuous Co-Separation by Liquid Absorption in Aqueous Cuprous Chloride (CuCl) and Magnesium Chloride (MgCl2) Solution

by Foster, Paul J

The purpose of the research was to design, build, test, and recommend a process to economically separate CO from a gas mixture of CO, CO2, and O2. The general method considered in this research to accomplish the separation was liquid absorption in a packed column. Several experiments were performed to identify the best process solution to use in a prototype. The experiments, based on the COSORB process, consisted of CuCl mixed with a complexing agent (metal tri-chloride) and a solvent (metal tetra-chloride, toluene, ethanol, etc.). The best method consisted of an aqueous solution of CuCl and MgCl2, which has previously been used for CO absorption experiments reported in the literature. The absorption takes place at elevated pressure (30 psig) and ambient temperature, and the stripping occurs at approximately 75 ºC.

Using the apparatus at approximate design conditions, the highest removal of CO was 88% with a product composition of 48%. The highest product composition achieved was 84%; in this case CO removal was 66%. Product composition was low because a significant amount of CO2 physically absorbed into solution (which also decreased the pH of the solution to about 4, according to calculation). The removal of CO should increase with a taller column and higher liquid flow through the column; however, this might decrease the product composition. Advantages of this process are that the raw materials used are relatively cheap, heating and cooling requirements are lower than similar processes, and operation is relatively simple.