Design configurations of the methanol synthesis loop

Abstract

In recent years the chemical industry has undergone considerable changes due to increased environmental regulations and energy costs. This master thesis has evaluated three different design considerations of the methanol synthesis loop using Honeywell's general purpose process simulator UniSim Design (R380 Build 14027) combined with MathWorks programming language MATLAB. The three configurations are Lurgis methanol reactor loop as built on Tjeldbergodden, the use of interstage methanol removal by the means of condensation and Lurgis MegaMethanol configuration. It was shown that the base case simulation of Lurgis reactor loop, using kinetics from Vanden Bussche and Froment (1996), gave reasonable results compared to Tjeldbergodden methanol plant. For the interstage methanol removal configuration it was found that the two reactors should be of equal length, 7.25 m, and that a cooling water temperature of 250 degrees C in the first reactor and 255 degrees C in the second reactor produced the highest amount of methanol. When operating with a recycle ratio of 2, this configuration had the potential of a net present worth of 47 million dollars compared to the base case over a 10 year horizon. The addition of a gas cooled reactor for the MegaMethanol process only increased the methanol production by 0.2 tonne/h, making the project unfeasible.