Plantwide control structures design of monoisopropylamine process

Abstract

In this work, plantwide control structure design procedure of Wongsri (2012) is presented and applied to the monoisopropylamine process. The plant consists of a tubular reactor and three distillation columns. There are two recycle streams: gas and liquid. The raw materials are isopropyl alcohol and ammonia which are converted to MIPA, DIPA, and water. The by-product DIPA is recycled to react with ammonia to form MIPA. An excess of ammonia in the reactor inhibits the DIPA reaction, so ammonia is also recycled. The plant with control structure designed called the fixture plant. The raw materials entered the process is fixed and the products are regulated according to their accumulation. The recycle flowrate of DIPA is adjusted by its quantifier. The temperature loops are designed to reject the thermal disturbance. The first distillation column is controlled using a single temperature and a reflux-to-feed ratio control structure. The second distillation column is controlled using a single temperature and either a reflux-to-feed ratio or reflux ratio control structure. The third column has three alterative control structures which are the same as the second column and dual control structure ratio (one temperature and one composition).