Removal of Sulfur Dioxide Emissions By Scrubbing With Oilfield-Produced Water
Authors: Snavely Earl S. , Bertness Ted A. 
Published: December 2007

Oilfield-produced water was successfully used to remove sulfur dioxide from the flue gas of steam generators fired with high-sulfur crude oil. This process cost less than sulfur removal processes or low-sulfur fuel. Water process cost less than sulfur removal processes or low-sulfur fuel. Water injectivity was improved by a decrease in pH caused by absorption of the sulfur dioxide.

Introduction

The San Ardo field is located in the south-central portion of the Salinas Valley, about 5 miles southeast portion of the Salinas Valley, about 5 miles southeast of the town of San Ardo in Monterey County, Calif. The field measures about 6 miles in length and 2 1/2 miles in width and extends over 4,200 acres. Heavy oil, 11 degrees to 13 degrees API gravity, is entrapped within several sands at drilled depths of generally less than 2,800 ft. The San Ardo oil field is one of California's major petroleum reserves. The well productivity and recovery petroleum reserves. The well productivity and recovery of the heavy, viscous crude oil is dependent upon thermal recovery processes, principally steam injection. The crude oil has an average sulfur content of 2 percent by weight and is used as fuel in the steam generators. The natural gas produced with the crude is insufficient to supply the fuel requirements. Alternate sources of low-sulfur fuel are in short supply in this area. The Monterey-Santa Cruz County Unified Air Pollution Control District (UAPCD) enacted Rule 415, effective July 1972, that prohibits the use of a fuel oil with a sulfur content greater than 0.5 percent. In Jan. 1972 the UAPCD adopted Rule 417 that stipulates "the provisions of Rule 415 shall not apply where sulfur compounds are removed from the stack gases to the extent that the emissions of sulfur compounds are no greater than that which would be emitted by using a liquid or solid fuel complying with Rule 415." This paper describes the method, testing, and performance of emission scrubbing to remove sulfur performance of emission scrubbing to remove sulfur dioxide from the combustion gases of the steam generators used in Mobil's thermal recovery operations at San Ardo.

Processes Considered Processes Considered The steam generators installed in the field are of two sizes with heat input of 22 and 50 MM Btu/hr. The generators are placed in groups of three to eight units at seven locations distributed over approximately three sections, or about half of the field. The various systems that were considered for gathering and processing the emissions from these widely scattered sources werecirculate an absorbent solution to the emission scrubbers on each of the steam generators and recover products and/or wastes in a central plant;compress the flue gas at each steam generator location and treat the flue gases and recover products and/or wastes in a central plant; andproducts and/or wastes in a central plant; andoperate small recovery plants at each steam generator location.

A generalized flow diagram of a central treating plant is shown in Fig. 1. Detailed economics of each of the above alternatives will not be discussed because conditions at San Ardo are not applicable to a general situation. The economics and flexibility of generator and process operations support the first method for the situation at San Ardo. Some idea of the quantities of raw materials required, and wastes and/or salable products generated by the various processes that were considered, are given in the following discussion.

JPT

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