Systematic Batch Process Development and Analysis via an Advanced Modeling and Simulation Tool

Batch chemical manufacturers face several challenges today, including reducing time-to-market, lowering costs, complying with growing regulatory requirements, minimizing waste and emissions and ultimately, increasing return-on-investment. Rapid, effective and informed process development is key to achieving these goals. An advanced modeling and simulation tool, such as BATCH PLUS, can help manage the decision-making and information needs of process development. INTRODUCTION The inherent advantages of batch processes, including their ability to produce multiple related products in the same facility, as well as their ability to handle variations in feed stocks, product specifications and market demand patterns, makes them well suited for the manufacture of low-volume, high-value products. For these reasons, batch processes are the production scheme of choice for the pharmaceutical, biotechnology, specialty chemical, consumer products and agricultural chemical industries. The production of these high value-added chemicals, as opposed to bulk, commodity chemicals, today contributes a significant and growing portion of the revenue and earnings of the chemical process industries. Several authors (Parakrama [1], Stinson [2]) have discussed the importance of batch processes in the process manufacturing industries. Batch chemical manufacturers face several challenges today. Reducing time-to-market, lowering costs, complying with growing regulatory requirements, minimizing waste and emissions and ultimately, increasing return-on-investment, are all major goals of the industry. Process development, the activity carried out to create a process for manufacturing a molecule or product previously synthesized only in the laboratory, is a key part of these goals. While the batch chemical industry has long recognized the need for rapid and effective process development, recent increased pressure to hasten the movement of products from research to consumer has resulted in greater attention being paid to this activity than in the past. Furthermore, given the growing trend in the industry towards products with short life cycles and products tailored to specific market needs (Macchietto [3]), rapid process development has become even more significant. Reducing the time for process development can result in quicker market penetration as well as longer exploitation of the protection accorded by patents. Many key decisions that impact profitability are made during process development. Better and more effective process development can help reduce costs and lead to a process with improved economic efficiency. With the current pressures of global competition, economic efficiency often dictates whether a manufacturer can compete on a cost basis, an issue of special relevance to the pharmaceutical industry, which is faced with a long government approval process for its products. Environmental concerns are also another key issue faced by batch chemical manufacturers today. The extent to which a manufacturing process impacts the environment is often dictated to a large extent by decisions that are made when the process is being developed. Process development decisions that are well made can help reduce environmental costs and undesired consequences in the long run. End-ofpipe solutions to unwanted waste and emissions can be avoided by smart process development. Pisano [4] has made a strong case for considering process development a major competitive weapon. He has presented extensive data from two batch industries, pharmaceutical and biotechnology, to support his claim. His data indicates that superior performance in process development can have a large positive impact on a firm’s competitive position. Over the last three decades, the use of computer-based modeling and simulation tools to support process development and design has become routine in the continuous chemical industry. However, this is still not the case in the batch process industry. The main reason for this has been the unavailability of such tools for batch processes until recently. A number of these tools are available today, including BATCHES (Joglekar and Reklaitis [5]), gPROMS (Barton and Pantelides [6]) and BATCH PLUS. The use of modeling and simulation tools can help reduce the length of the process development life cycle. Such tools can also support the development of processes that are more efficient, environmentally friendlier, safer and more cost effective by allowing more process alternatives and options to be evaluated. They can support material selection, equipment sizing and design, scale-up and process optimization. Besides facilitating process development, these tools have several other benefits as well, as indicated by Andrews and Bacher [7]. By capturing relevant process information in the form of models, flowsheets and recipes, they can help support technology transfer among different groups. Process development is never the exclusive domain of any one community. Laboratory chemists, pilotplant engineers, process engineers and production-floor operators, among others, all play a role in process development. Modeling and simulation tools can also be used to train development engineers and chemists within industry. Andrews and Bacher estimate that it takes three to five years for an engineer to become well-versed in process development and they believe that process simulation could be used to shorten the training cycle. This paper describes the BATCH PLUS modeling and simulation system. It presents an overview of the system and its architecture, the models available in its libraries, its main algorithms, the key results that it generates and the different ways in which the system has been used to support process development.