Fellowships
PI: Adrianna Kirkman
University: North Carolina State University
Research Partner: Steve Phillips
Research Partner Laboratory: National Renewable Energy Laboratory
Abstract:
The sustainable and cost-effective conversion of biomass to biofuels or bioenergy requires the complete and careful utilization of the biomass feedstocks. A key element in the development of these conversion processes includes integration of process heat and energy, including biomass drying. Many of these heat and energy integration questions can be answered with modeling software.
Process modeling is a efficient and cost-effect method to highlighting the technical and economic challenges for developing new technologies. Process modeling is particularly valuable for evaluation of new processes or for the integration of new processes into existing facilities. In this case process modeling can be used to evaluate the economic potential for integrating biofuels and bioenergy technology into and existing pulp and paper mill. The process modeling will highlight the economic potential in terms of capital savings, and the technical challenges. In particular, process modeling can be used to highlight the benefits of overcoming technical barriers. This type of analysis can then be used to focus research and develop activities on the technical barriers that will have the greatest impact.
NCSU, in conjunction with a group of 9 industrial partners has been developing a process model for the production of bioethanol in a pulp and paper mill that has been closed. This modeling work has been focused on the reuse of the capital equipment, e.g., biomass boilers, batch or continuous digesters, bleach towers, wastewater treatment plants and biomass feed handling systems, and the mass and energy balances for the different unit operations, e.g., pretreatment, enzymatic hydrolysis, fermentation, distillation and power production.
This process model has been developed using WINGEMS, a process modeling program that is well-accepted by the pulp and paper industry. While WINGEMS has well develop modules for the production of pulp, for heat and water integration and recycle, and for the chemical recovery cycle, it does not have modules that effectively model enzyme hydrolysis, fermentation or distillation. Conversely NREL has developed two very detailed process models for the production bioethanol; one using enzyme hydrolysis, fermentation and distillation (Biochemical Processing), and the second using biomass gasification followed by the catalytic conversion of syngas to ethanol (Thermochemical Processing). These process models were developed using ASPEN processing modeling software.While these ASPEN models are well-developed they can not be easily integrated into a WINGEMS model, and vice versa.
The goal of this work will be to begin the process of integrating the information contained in the WINGEMS and ASPEN process models to develop a single process model that can accurately model the biochemical or thermochemical conversion of biomass to ethanol. Although, at this point it is not clear how this integration should be done. This collaboration will allow Dr. Adrianna Kirkman, an expect in WINGEMS and the technical lead on the process modeling work that has been done at NCSU, to work with the NREL staff for three weeks and develop a plan for the integration of these two modeling approaches.
