Title

Design, Development and Analysis of a Preparative Scale Ion Exclusion Chromatography System

Date of Award

1991

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Polymers and High Performance Materials

First Advisor

Roger Hester

Advisor Department

Polymers and High Performance Materials

Abstract

The economic feasibility of using cellulose hydrolysis to convert wood and agricultural waste products such as corn stovers to fuel alcohol is dependent upon developing a cost effective acid/sugar separation process. Presently, an acid/sugar stream resulting from sulfuric acid hydrolysis of cellulose is treated with lime to precipitate the acid as gypsum. The sugars, glucose and xylose, remaining in the acid free stream can thereafter be converted to ethanol by fermentation. This precipitation technique not only expends acid and lime, but also generates significant quantities of waste gypsum that need to be disposed to a landfill. The use of ion exclusion for acid/sugar separation has proven more cost effective than precipitation because no waste products are formed and the acid can be recovered and reused in cellulose hydrolysis. An ion exclusion process to perform acid/sugar separation has been designed using commercially available resins. Economic analysis based on experimental data indicates that ion exclusion is 50% less costly than the lime precipitation process. Thus, the ion exclusion separation process is commercially attractive. An existing process computer model has been modified to account for secondary effects present in ion exclusion. The effect of changes in resin geometry with fluid composition were included in the process model so that more accurate predictions of ion exclusion performance could be made. The application of ion exclusion technology to several acid/sugar hydrolyzate feedstocks was investigated in detail. These hydrolyzates were obtained from the acid hydrolysis of cotton linters, rice straw and municipal solid waste. The municipal solid waste hydrolyzate occasionally has trace metal impurities that could cause extensive damage to ion exclusion resin pore structure, thereby reducing its separation performance. Further experimental research is needed to determine whether long term chemical poisoning or physical degradation of the resin would impede ion exclusion capabilities.