Desalter/WWTP Integration Improves Refinery Profitability, Reduces Chemical Costs and Improves Environmental Compliance When Processing Tight Oil Crudes

Case Study

Desalter/WWTP Integration Improves Refinery Profitability, Reduces Chemical Costs and Improves Environmental Compliance when Processing Tight Oil Crudes

Challenge The resulting recommendations from this investigation focused around a new chemical package In 2012, an Eastern Canadian refinery began experi- for both the desalter and WWTP. The new chemi- encing high influent waste water turbidity caused by cal package addressed all of the challenges of elevated levels of oily solids originating from the de- processing high-solids; tight oil crude slates and salter brine as a result of processing a high-solids linked the interaction of all of these chemical crude diet, containing highly profitable shale oil or treatments into a successful overall chemical pro- “tight oil” crude. The high concentration of oily sol- gram. The main recommendations included: ids in the influent waste water was not being re- moved effectively in the Waste Water Treatment 1. Transition of desalter primary emulsion Plant’s (WWTP) primary treatment unit (Oily Water breaker to GE’s Embreak* 2W2030 product to Separator/DAFs). The poor quality water leaving the improve brine quality primary treatment unit resulted in detrimental ef- 2. Upgrade of KlarAid* coagulant chemical fects on the biological treatment unit, issues with injection facilities for the DAF to improve final clarification and an oil sheen presenting on the chemical dosage control final effluent. 3. Addition of GE’s PolyFloc* flocculant chemistry In response to the environmental issues, the plant to the DAFs was forced to reduce the amount of high-solids “tight oil” crudes processed, reducing the refinery’s 4. Transition from coagulant chemistry to GE’s profitability. Costs related to contingency tertiary Novus* flocculant as the final clarification aid treatment (oil booms, vacuum trucks etc.) and waste water sludge dewatering issues compounded the Results costs incurred by this issue. The implementation of the above recommendations has resulted in a number of key improve- Solution ments in the desalter and WWTP operation that GE assembled a multi-functional team of desalter have reduced the variability of the operation rela- and waste water technical leaders to study the is- tive to solids and oil contamination of water sue and recommend chemical and operational streams. Ultimately, they mitigated the possibility changes required to improve the desalter brine and of a repeat of the final effluent quality issues pre- final effluent quality while processing all desired viously experienced including: crude slates. Extensive bench testing of both desalter and WWTP chemistry were conducted as part 1. Reduced frequency of the presence of free oil of this investigation to select a chemical program and oil-coated solids in desalter brine leading that would achieve this goal. to reduced DAF influent turbidity

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CS1455EN.doc Feb-14

2. Improved oil/solids flocculation at the DAFs Table 3 - Final Effluent Turbidity (NTU) leading to improved contaminant removal and reduced DAF effluent turbidity With With Coagulant Novus 3. Improved sludge-water separation in the DAF Flocculant oily sludge holding tank Average 6.11 3.29 4. Improved final clarifier bed compaction Standard Deviation 3.36 1.75 5. Reduced final effluent turbidity 6. Reduced chemical usage Customer Benefits 7. Improved waste water sludge dewatering unit The above presented results show that a signifi- operation relative to chemical flocculation cant operational improvement has been effected by the implementation of the GE-recommended Many of these improvements can be displayed sta- chemistries through integration of the desalter tistically. Graphs and tables showing these statisti- and WWTP performance. The more robust chemical results are presented below: cal program, coupled with an improved operational rigor and attention to maintenance items within the WWTP has led to a confidence in the customer’s ability to process “tough-to-treat” high-solids crudes at both the desalter and WWTP. More importantly, the changes made have al- lowed the refiner to run the most profitable crude slates without fear of WWTP effluent discharge issues. Financial benefits resulting from the improvements are summarized below: 1. $9,100,000/yr increase in profitability from running higher percentages of high-solids tight oil crudes. Table 1 - DAF Influent Turbidity (NTU) 2. $1,000,000/yr in savings from eliminating con- tingencies associated with WWTP final efflu- Prior to After ent quality issues (i.e. vacuum trucks, oil Transition to Transition to booms etc.). Embreak Embreak 2W2030 2W2030 3. $1,000,000/yr in savings from eliminating the need for contracted dewatering services to Average 163.38 72.93 handle excess oily sludge and biosludge in- Standard Deviation 116.30 43.16 ventories. 4. $250,000/yr savings in reduced WWTP chemical costs. Table 2 - DAF Effluent Turbidity (NTU)

Coagulant Coagulant Only and PolyFloc Flocculant Average 30.49 15.80 Standard Deviation 41.46 11.60

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