US EPA

1629159 

Journal Article 

Design and Control of the Monoisopropylamine Process 

Luyben, WL 

2009 

Yes 

Industrial and Engineering Chemistry Research
ISSN: 0888-5885
EISSN: 1520-5045 

48 

23 

10551-10563 

10.1021/ie900965s 

WOS:000272039200050 

The monoisopropylamine (MIPA) process provides an
interesting example of plantwide economic design optimization and plantwide control. The process
consists of a tubular reactor and three distillation columns. There are both gas and liquid
recycles. Fresh feed streams of isopropyl alcohol and ammonia are introduced into the process.
The desired products are MIPA and water. An undesirable byproduct of di-isopropylamine (DIPA) is
also produced and is recycled to extinction since its formation reaction is reversible. An excess
of ammonia in the reactor inhibits the DIPA reaction, so ammonia is also recycled. The purpose of
this paper is to present the details of the process for use by other workers as a test case for
use in plantwide design and control studies. A heuristic economic optimum design and a control
structure are developed. The process illustrates the classical design trade-off between reactor
costs versus separation costs. In addition, the process has two recycles, which are both
distillate products from different distillation columns, and this leads to another trade-off.
Using more ammonia recycle produces less DIPA recycle. So the optimum design must balance the
separation costs of the two recycles. Two of the distillation columns can be effectively
controlled using a single temperature and a reflux-to-feed ratio control structure. The third
column requires a dual control structure ratio (one temperature and one composition).