EZ-CAUSTIC~R On-line Analyzer System for the Control of NaOH Scrubbers in Refining and Olefins (Ethylene) Production Plants

摘要

The caustic wash process is a necessary yet costly purification step in refining and olefins plants, inciting manufacturers to cut down on the considerable expenditures in commodity chemicals (NaOH). Concentration of the fresh chemicals has to be kept as much as possibly stable around a certain set point, with every deviation leading to less end product quality or increased give-aways. Continuous monitoring by means of an automatic (on-line) titration system with a novel sampling system, briefly the EZ-CAUSTIC~R, was developed by AppliTek to determine the concentration of the chemicals. By measuring on-line three critical process parameters, the analyzer system is capable of narrowing significantly the process set point. This paper demonstrates also the considerable profits that are possible once the purification process is closely monitored and fine-tuned. In one specific medium-sized olefins plant it was observed that, on an average base, a reduction of 350 kg per hour of NaOH could be accomplished, leading to a profit of approximately 1,200,000 USD per year.