CC-02-156 BENEFITING FROM THE USE OF SMART INSTRUMENTS AND ASSET MANAGEMENT SOFTWARE IN NAPHTHA CRACKING

Description:

Petroquimica União S.A. is the third largest -- but the most profitable -- petrochemical plant in Brazil. Its output of approximately 4000 tons per day is broken out into some 1400 tpd of ethylene, 700 tpd of propylene, 530 tpd of C4 chemicals, and 1300 tpd of aromatics. The company's primary markets in order are plastics, intermediates, and fibers. A major reason for PQU's good profitability of late is its ability to squeeze more high-value products from feedstocks. This was not always the case. Like many petrochemical plants, we had a problem with excessive process variability adversely affecting product output and quality, even when our operators were trying their best. The problem was not in the people or the process control equipment, but in our difficulty in recognizing that such variations existed. Initially we found that process variations existed to a much greater degree than most people realized through a very revealing Emerson Process Management conducted Process Variability Audit program. Lack of awareness is due in part to the fact that existing control systems seldom measure and display variations with sufficient integrity and precision. Additionally, people tend to accept many variations as normal even though a significant number can be eliminated or reduced. Before going into detail on the process audit projects at PQU, and the rather astounding results from corrections made, a discussion of the problems wrought by process variability would be in order.