Integrating CANSOLV^® System Technology into your sour gas
treating / sulfur recovery plant.

 
Nathan A. Hatcher & Johnny E. Johnson, Black & Veatch Pritchard, Inc.
Leo E. Hakka & Paul J. Parisi, Cansolv Technologies Inc.

Presented at Laurance Reid Gas Conditioning Conference
Norman, Oklahoma - March 1 to 4, 1998

ABSTRACT

The CANSOLV^® System SO2 scrubbing technology is an emerging regenerable process for economical, highly selective capture of SO2 from gas streams, down to a few ppm if desired. In gas production and sweetening plants (GTU’s), the technology can be used to control sulfur emissions from sulfur recovery units (SRU’s), cogeneration units, and power boilers. The pure, water saturated SO2 byproduct from all these sources can be fed into a new or existing SRU for conversion to sulfur. Process costs with the CANSOLV^® System technology are largely insensitive to the concentration of SO2 in the feed gas. Therefore, high-sulfur, low-value fuels such as GTU flash gas can be burned in place of more valuable sweetened product natural gas.

SRU tail gas cleanup with CANSOLV^® System technology competes with current known BACT technologies (e.g. ARCO, SCOT, BSR-Amine). However, the CANSOLV^® System technology offers distinct technical and economic advantages for certain sulfur recovery situations.

• Since the tail gas is incinerated in excess air prior to scrubbing, all sulfur species are converted to SO2 and captured to minimize total sulfur emissions.
• MACT status can be achieved -- to 10 ppmv SO2.
• Troublesome streams such as SWS gas, and sulfur-laden waste streams which often plague refinery SRU’s may be directly incinerated, then recycled to the SRU as SO2 from the CANSOLV^® Regenerator.
• SRU capacity can be expanded at low capital and operating cost by feeding part of the acid gas, preferably the troublesome streams such as sour water stripper gas and hydrocarbon rich streams, to the tail gas Thermal Oxidizer. There, the excess air destroys species like ammonia and hydrocarbons. Only the SO2 is removed from the combustion gases by the CANSOLV^® System and is introduced to the SRU front end. This eliminates the flow of inerts (N2, CO2, H2O) through the SRU that would be otherwise contributed by partial combustion of the bypassed acid gas.
• When acid gas bypass is maximized, a new process paradigm, the “CANSOLV^® System SRU”, is created. This process configuration offers maximum sulfur recovery at minimum cost, and allows processing of acid gas with lower H2S concentration.

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