Process Modeling, Optimization, and Economics Evaluation

Session Chair:

• Peter Clark, Scale-up Systems

Session Description:

This session will explore how modeling, optimization and economic evaluation activities are applied throughout the development of “green” and sustainable processes, especially those centered on high water use / dilute aqueous streams.  Talks that include the following elements are particularly welcome: 

• Case studies showing how process modeling, optimization and economics evaluation activities helped to achieve key development milestones, and how these activities were conducted alongside laboratory, pilot plant and other scale-up studies;
• Surveys of currently available methods and tools for these activities;
• Explorations of similarities and contrasts between methods, tools and models used to facilitate development of “high water” processes with those used to develop “traditional” processes;
• Assessments of gaps in the methods, tools and models currently used to facilitate process development, optimization and economics evaluation.

Schedule:

Abstracts:

Evaluating and Reducing Water Usage in Bio-processing

Charles Siletti, Intelligen

Fermentation and cell-culture processes are extremely water-intensive. They may require over 10,000L of water for every kilogram of product. Furthermore the majority of this water must be highly purified. This presentation describes the results of a series of simulation studies aimed at evaluating the effect of process design options on water consumption. In a typical stainless steel cell-culture process, equipment clean-in-place (CIP) is the largest consumer accounting for over 60% of the total water usage. Single-use bio-reactor systems and vessels eliminate much of the CIP water requirement and represent the single most effective means of water reduction. There are, however practical and economic limits to their application. In cases where fixed equipment is unavoidable, some process design considerations can reduce consumption. In general, water reduction designs favor larger batchsizes and fewer cycles. Cell-culture optimization can reduce water by reducing bio-reactor size requirements although this will have little effect on the downstream water consumption. In-line buffer dilution can reduce the size requirements and therefore the amount cleaning water for buffer prep tanks.Single-use chromatography systems can reduce water consumption by eliminating column preprocessing and storage operations. Operational improvements and good clean and dirty hold management can further reduce water consumption.

Enabling Bioprocess Development using Virtual Plant Technology

John Bomberger* and Tracy L. Clarke-Pringle, DuPont

Dynamic process modeling is a valuable tool for understanding process behavior and testing new ideas in a safe and secure environment. It can be used to identify and test new operating conditions, process configurations, control strategies, or operating procedures that increase yield, reduce costs, or impact other important performance indicators. Dynamic models can also be extended in order to train new and existing operators on unusual or emergency conditions, reducing operator error, improving operational consistency, and making hazardous processes inherently safer to run.

Over the last several years, DuPont has made a clear, long-term commitment to developing and operating bioprocesses. Enabling the DuPont strategic direction in biotechnology depends on Virtual Plant Technology. Virtual Plant Technology refers to the application of dynamic modeling to address the needs of the project development cycle, including evaluation and testing of process alternatives during design, operability studies, control structure design and testing, DCS configuration testing, and operator training. Dynamic modeling and simulation are often more critical in bioprocess development than in traditional chemical processes. Bioprocesses may have complex flowsheets and make extensive use of batch or combined batch / continuous processing. Because many bioprocesses have high water loads, water recycle and inventory management can become problems in such an environment. Further, plant-wide batch automation may be challenging, requiring synchronization of different batch unit operations, arbitration of shared equipment, and coordination with the continuous processing units, while maintaining the operating conditions at their targets and within constraints. Additionally, steady state process models may not accurately determine variability and maximum or minimum loads on equipment and utilities. Therefore, dynamic simulation is an important tool to understand the inherently complex dynamic behavior of the integrated bioprocess, the use of which translates into better design, operating policies, understanding of constraints, and process control, and opens the door for significant financial benefits.

DuPont™ TMODS, a proprietary dynamic modeling software package developed and maintained by the Dynamic Simulation, Control, and Optimization Group in DuPont Engineering Research and Technology (DuET), is by far the most commonly used dynamic simulation tool in DuPont. As such, the modeling capability in DuPont™ TMODS is highly leverageable, and the tool has very broad use and acceptance across DuPont. DuPont™ TMODS and dynamic modeling are key components of Virtual Plant Technology as practiced in DuPont. For the last two decades, Virtual Plant Technology has been used throughout DuPont’s chemical and polymer businesses to improve process understanding and make processes more profitable. This talk will focus on how Virtual Plant Technology is being used in DuPont to support the development of bioprocesses. For example, it has been used to study process alternatives, such as the effect of different bioreactor designs or the use of perfusion and cell recycle, and to support the process economic evaluation of those alternatives. It has also been used to develop control strategies and study process operability, especially with regard to the large water flows, recycle streams, and inventories typical of bioprocesses, leading to important changes in process design. Virtual Plant Technology has also played a vital role in bioprocess commercialization, including operator training simulators, control system functional description development, and control system configuration and checkout.

Understanding Synergies between Catalytic Fast Pyrolysis and Processes Based on Conventional Energy Feedstocks through Insights from Techno-Economic Analysis (TEA) Studies

Asad Hasan Sahir*, Michael Talmadge, Mary Biddy, and Abhijit Dutta, National Renewable Energy Laboratory (NREL)

Conventional energy processes based on petroleum feedstocks (e.g. Fluid Catalytic Cracking, Hydroprocessing, Hydrocracking and Delayed Coking) can play a vital role in facilitating understanding of the process engineering aspects for in situ and ex situ catalytic fast pyrolysis vapor upgrading. The higher oxygen content of biomass and its tendency towards coke and gaseous species formation serves as a major differentiating factor between conventional petroleum refining processes, and biomass-based thermochemical processes like pyrolysis.

The development of 21 billion gallons of advanced biofuels annually by 2022 is mandated by the U.S. Energy Security and Independence Act of 2007. The potential of in situ and ex situ upgrading of fast pyrolysis vapors as one of the promising research options for thermochemical conversion of biomass to liquid transportation fuels has been explored in a thermochemical research pathway process design report (http://www.nrel.gov/docs/fy15osti/62455.pdf). Based on the understanding derived from process engineering literature on Fluid Catalytic Cracking, the possible implications of a significant coke content observed in current experimental studies on catalytic fast pyrolysis vapor upgrading can be understood, and will be discussed in this presentation.