A dual-temperature control challenge

摘要

In his March 2010 "HPIn Control" column (p. 17), Y. Zak Friedman challenged me "to write an article showing a real column having stable dual-temperature control." I have written many such articles in the past, so the history of success is well established. For example, see the application to a styrene-ethylbenzene column (Oil & Gas J., July 14, 1969), to an alkylation deisobutanizer (Oil & Gas J., July 28,1969) and to a series of columns in an NGL sepa-ration unit (Chem. Eng. Progr., June 1975). Obviously, this is not news.