Chapter 6 – Combining Mass-Integration Strategies

Publisher Summary This chapter provides an outlook on the combination of different integration tools, such as systematic mass-integration tools, direct recycle, and mass-exchange networks as a mass-integration strategy. Once an overall mass target is determined, it is necessary to develop cost-effective strategies to reach the target. Mass integration is a holistic and systematic methodology that provides a fundamental understanding of the global flow of mass within the process and employs this understanding in identifying performance targets and optimizing the allocation, separation, and generation of streams and species. Mass integration is based on fundamental principles of chemical engineering combined with system analysis using graphical and optimization-based tools. Interception denotes the utilization of new unit operations to adjust the composition, flow rate, and other properties of certain process streams to make them acceptable for existing process sinks. A particularly important class of interception devices is separation systems that may be induced by the use of mass-separating agents (MSAs) and/or energy-separating agents (ESAs). The combination of mass-integration tools is demonstrated through the applicability to a case study on the production of acrylonitrile. Application of mass integration to debottleneck an acrylonitrile process reduced water usage and discharge. The first step in the analysis is to identify the target for debottlenecking the biotreatment facility. An overall water balance for the plant has to be calculated. It is beneficial to detail the direct-recycle strategies to attain the identified targets. Fresh-water usage and influent to the biotreatment facility were decreased by 7.2 kg/s. The value of fresh water and the avoidance of treatment cost are additional benefits.