Grantee Research Project Results
Liquid Carbon Dioxide-Based Leather Processing
EPA Grant Number: GR833356Alternative EPA Grant Number: R833356
Title: Liquid Carbon Dioxide-Based Leather Processing
Investigators: Raynie, Douglas E.
Institution: South Dakota State University
EPA Project Officer: Hahn, Intaek
Project Period: June 1, 2007 through May 31, 2010
Project Amount: $322,950
RFA: Greater Research Opportunities: Environmentally Benign Manufacturing and Processing (2006) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , Sustainable and Healthy Communities
Description:
This research will explore the broad-scale application of liquid carbon dioxide to unit operations in the leather processing industry. It is possible that the use of liquid carbon dioxide could replace a number of aqueous and VOC–based solvents. This change may also facilitate the reclamation and reuse of active chemicals used in the re-tanning, waterproofing, and dyeing operations. The procedures will focus on hide degreasing and the post-tanning finishing aspects of the industry, as well as seek novel tanning methods. Manufacturing benefits include faster processing time; environmental benefits include reduced VOC and wastewater discharges. This research could lead to a major change in the processing of various leathers with a highly significant reduction of the industry’s impact on the environment. It could also lead to significant cost reductions and encourage the further development of this industry in the US.
Objective:
The objective of this project is to assess the enhanced diffusivity of carbon dioxide-based solvents for hide degreasing, tanning, waterproofing, dyeing, and other key leather-processing steps. Integration of these steps in a semi-continuous fashion will be a guiding factor in process development. Life-cycle and economic assessments will compare developed technologies to existing practices.
Approach:
The use of liquid carbon dioxide for leather re-tanning, waterproofing, and dyeing possess the highest likelihood of success and will be investigated first. Improvements to the hide degreasing and de-liming steps will be expanded to address shortcomings with similarly developed processes. Carbon dioxide-miscible surfactants and selective co-solvents for chrome, vegetable, and synthetic tanning agents will be examined for possible use. Finally, integration of these processes will be addressed and a life-cycle assessment will be performed.
Expected Results:
The proposed project is expected to produce an integrated system for the leather processing industry using liquid carbon dioxide. The increased diffusivity of carbon dioxide solvents will result in faster processes and lower associated processing costs. Eliminating or curtailing the use of aqueous and organic solvents will minimize VOC emissions and wastewater discharges, the major environmental concerns in the leather industry, with reduced abatement and monitoring costs.
Supplemental Keywords:
supercritical fluid, leather tanning, dyeing, nonaqueous solvents, liquid carbon dioxide, VOC, heavy metals, green chemistry, pollution prevention,Progress and Final Reports:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.