2000 Progress Report: Polymer-Based Aqueous Biphasic Extraction Technology for Reaction Engineering of the Alkaline Paper Pulping ProcessEPA Grant Number: R826732
Title: Polymer-Based Aqueous Biphasic Extraction Technology for Reaction Engineering of the Alkaline Paper Pulping Process
Investigators: Rogers, Robin D. , April, Gary C. , Huddleston, Jonathan G. , Wiest, John M.
Institution: University of Alabama - Tuscaloosa
EPA Project Officer: Richards, April
Project Period: October 1, 1998 through September 30, 2001 (Extended to December 30, 2002)
Project Period Covered by this Report: October 1, 1999 through September 30, 2000
Project Amount: $350,139
RFA: Technology for a Sustainable Environment (1998) RFA Text | Recipients Lists
Research Category: Sustainability , Pollution Prevention/Sustainable Development
Objective:The objective of this project is to utilize wholly aqueous systems, such as polymer-based aqueous biphasic systems, as an environmentally benign extraction media for the separation of reaction products during the pulping process, and thus reducing chemical and energy consumption, eliminating emissions, and increasing the efficiency of the pulping process.
Progress Summary:We investigated the effect of the addition of polymers to a standard pulping solution on Kappa number, pulp yield, and residual alkali of softwood and mixed hardwoods under temperatures and pressures equivalent to current alkaline paper-pulping practices. As the result of the addition of polymer to the process, less energy was needed to produce similar Kappa numbers and achieve pulp yields that far exceed those measured for bleachable pulps in a Kraft process. The addition of polymer to the process also yielded an increase in residual alkali found in the cook. The more residual alkali left in the cook indicates fewer chemicals were consumed in the process, and as a result, more chemicals are available for recycling.
We have begun to develop a kinetic model to describe delignification in polymer-base aqueous biphasic systems. These models enable us to compare each of the pulping processes we have studied based on activation energy. From the activation energy, we can determine the most energy efficient process. We have found that the addition of polymer to the process results in lowering the activation energy. Lower activation energy results in less energy and lower temperatures needed to run the process.
Effective design and use of aqueous biphasic separation strategies involving polyethylene glycol require an understanding of why these systems form two distinct phases and how solutes partition themselves between the phases. From a molecular thermodynamics point-of-view, this means developing an understanding of how the molecular architecture and inter- and intra-molecular interactions govern the Gibbs free energy of the solution. We have been simulating ethylene glycol oligomers. In particular, we have been conducting Monte Carlo simulations of a particular model for the system. This model uses a united atom representation for the polymer chains with potential parameters obtained from the literature. The results indicate that the conformational populations change around the C-C bonds in intriguing ways with both polymer concentration and temperature.
Future Activities:Semi-batch extraction/reaction systems will be used to simulate separations of lignin from the cellulose fraction of wood under realistic conditions. These results will be compared to those obtained from the batch experiments and to those obtained from the traditional Kraft pulping process to determine the benefits of adding polymer to the chemical pulping process.
We are developing analytical techniques to identify and study the raw materials that are left behind in each of the two phases of the cook after pulping. We also are investigating new materials that could be obtained from lignin using an enzyme to depolymerize lignin into smaller aromatic constituents.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
|Other project views:||All 50 publications||18 publications in selected types||All 18 journal articles|
||Willauer HD, Huddleston JG, Li M, Rogers RD. Aqueous biphasic systems for the separation of lignins from cellulose in the paper pulping process.. Journal Of Chromatography. 2000;743(1-2):127-135.||