Warm-Gas Desulfurization Process for ChevronTexaco Quench Gasifier Syngas

摘要

ChevronTexaco's innovative high efficiency quench gasifier produces a mediumrnBTU syngas that is essentially free from all contaminants except sulfur gases (H2S andrnCOS), ammonia, and traces of mercury. Several modular gas cleanup processes are beingrndeveloped to specifically target these contaminants by a research team including RTI,rnChevronTexaco (CVX), KBR, SRI International, and Süd-Chemie, Inc. This paperrndescribes the progress with installation, commissioning and testing of RTI's warm-gasrndesulfurization (WGD) process using a slipstream of syngas from CVX's three ton coalrnper day research gasifier at Montebello, California. A transport reactor system (16ft ×rn16ft × 80 ft) was installed and commissioned in March 2004 at Montebello. 300 lbs ofrnRTI's attrition resistant RTI-3 zinc oxide-based sorbent was loaded in the system forrntesting. The circulation of the sorbent was initially established using nitrogen. Thernsystem consisted of two coupled circulating fluidized-bed reactors for the desulfurizerrnand the regenerator. The sorbent was circulated at about 1600 lb/h in the desulfurizerrnloop. Approximately 25% of the sorbent was transferred to the regenerator loop and backrnto the desulfurizer. Nitrogen was replaced with syngas from the CVX gasifier containingrnabout 8000 ppmv of H2S and 200 ppmv of COS on a dry basis. The process wasrnoperated at 600 psig and 700 ℉ with 10,000 scfh of syngas. The sorbent removed therngaseous sulfur compounds to 1 ppmv. Laboratory tests of sorbent after more than 50rnhours of circulation showed no decrease in its attrition resistance and its reactivity. CVXrnrecently made a business decision to close down the Montebello facility. The testing wasrnthus suspended in April 2004. RTI is actively pursuing the installation of the WGDrnprocess at another host site. The plan is to run several long-term tests (500 h) torndemonstrate the long-term performance of this process, including the dual looprncirculating fluidized-bed system as well as RTI-3 sorbent.