When Processing Opportunity Crude Oils, Don't Forget the Wastewater!

摘要

Petroleum refiners choose crude oil slates based on many factors, typically driven by overall economics. Effects on wastewater treatment reliability are usually not highly prioritized in these analyses. Wastewater is generated in most process areas in a refinery, including the sour water strippers and desalters. This paper describes a data correlation exercise relating crude oil slate to wastewater quality based on variable crude slate characteristics at a large USA refinery. Seventeen measured characteristics of 42 crude oils, and daily flows of each over an 8-month period were used to compile a database containing daily composite crude oil characteristics. Wastewater effluent quality, the ultimate dependent variable, was correlated with composite crude oil characteristics. Run charts, least squares correlations, and cumulative sum charts of daily average data were used to find relationships between composite crude oil characteristics and wastewater effluent quality. Data suggested several causative factors that propagated through the desalters and all wastewater unit operations, affecting effluent quality. A new method used to predict effects of various crude slate characteristics on wastewater treatment effluent quality is demonstrated. Data from wastewater effluent modeling could be incorporated into refinery crude run models to add anticipated effects on wastewater treatment. This allows for proactive wastewater process capability determination, and mitigation of deficiencies found to ensure environmental compliance and optimum wastewater discharge quality. Furthermore, predictive modeling could be applied to allow for increased processing of the opportunity crudes that benefit operating margins and profitability.