Abstract

Recovery of the substantial crude oil reserves in central California has been restricted by stringent state regulations limiting the NO emissions from steam generators used to enhance the recovery process. These regulations specify that emissions reductions below a baseline level are required when certain ambient NO triggering levels are exceeded. There have been nocomprehensive test programs aimed at defining baseline emissions from steamgenerators or the effects of design parameters on those emissions. There have, however, been many individual tests of steam generators that have been performed primarily to comply with licensing requirements and these show that NOx emissions from standard 15 MW (50 × 10-6 Btu/hr) generators vary by a factor of five, from 160 to 825 cm3/m3 NOx corrected to 3 percent O2. Clearly, this indicates a need to identify an established baseline to which emissions levels from alternative configurations may be compared.

The study described in this paper entailed compilation of all available test results and analysis of these to 1) define the NO emissions baseline, 2)delineate the effects of several design variables on emissions, and 3) address the effectiveness of field tested NO reduction techniques and equipment. From these results, the 15 MW (50 × 10-6 Btu/hr) steam generator with a conventional burner was observed to be the most common configuration. The type of burner and steam generator were found to be relatively unimportant, probably because of similarities in design between manufacturers. The generator capacity was of greater importance. Steam generators with 6 MW (20 × 10-6 Btu/hr) nominal capacity exhibited NOx emissions exceeding the 15 MW (50 × 10 Btu/hrconventional burner levels, as did 15 MW (50 × 10-6 Btu/hr) generators equipped with low excess air burners (designed for high thermal efficiency). Field test results from two NO reduction methods were also analyzed. Ammonia injection into the combustion products showed significant effect on NO emissions; current technology low NO burners were characterized by emissions near conventional burner levels.

Introduction

Deteriorating air quality in the San Joaquin Valley of central California has prompted the state's Air Resources Board (CARB) to regulate NO emissions from thermal enhanced oil recovery (TEOR) steam generators in Kern County, where the majority of TEOR operations are located. These regulations require that 1) certain new stationary sources (including steam generators) use either the Best Available Control Technology (BACT) or the Lowest Achievable Emission Rate (LAER) to control emissions of any air contaminant or precursor for which there is a national ambient air quality standard (this includes NO), and 2) NOx emissions from all steam generators be reduced to 0.3 lb/10-6 Btu (about 225 cm3/m3) by July 1, 1982 with further reductions to 0.25 and 0.14 lb/10-6Btu (about 190 and 105 cm3/m3) if certain ambient NO levels are exceeded.(Note: all concentrations included in this report are corrected to 3 percent 02. Also, the units cm /m are equivalent to the more familiar ppm by volume.)the CARB emissions reduction levels were based on an inventory of steamgenerator emissions which assumed that the baseline NO emission level from conventional generators was 300 cm /m.

The specific objectives of this investigation were to:

. Characterize the NO emissions from the TEOR steam generator population;

. Determine the effects of various design and operating variables on NO emissions; and

. Evaluate the potential for achieving the regulated emission levels using current commercial equipment or technologies under development.

All available results from field tests of steam generators were compiled. Data were obtained from several steam generator owner/operators and from the records of CARB and the Kern County Air Pollution Control District (KCAPCD).Most of the data were the results of emissions compliance tests or tests conducted by independent test agencies.

P. 263

This content is only available via PDF.
You can access this article if you purchase or spend a download.