A reliable measurement of the temperature inside the reaction chamber of an entrained-flow gasifier isvery important. This is because the temperature must be maintained within a narrow range. The upperbound is set by the need to limit the rate of refractory deterioration. The lower bound is set by the needto control the viscosity of the slag to a low enough value so that it will flow down the wall and, thus,ensure adequate slag removal through the bottom of the reactor. In addition, an accurate knowledge ofgasifier temperature is very important during gasifier startup. And, during normal operation, thetemperature instrumentation must provide a rapid and reliable indication of deviation from normaloperation, such as a failure of one of the feed systems or a sudden change in feed quality.ChevronTexaco's Montebello Technology Center (MTC) has developed an infrared ratio pyrometersystem for measuring gasifier reaction chamber temperature. The system attaches to the gasifier usingone of the sidewall nozzles normally used for gasifier thermocouples. It views the interior of therefractory lined gasifier reaction chamber through a purged, optical access port. This system has afaster response time than both thermocouples and inferential techniques using syngas methanemeasurements, and has been demonstrated to provide reliable temperature measurements for longerperiods of time when compared to thermocouples installed in the same gasifier. In addition, the systemcan be applied to commercial gasifiers without any significant scale-up problems.Under the auspices of DOE Cooperative Agreement No. DE-FC26-99FT-40684, ChevronTexacohas constructed a commercial prototype of this pyrometer system for field testing in a commercialgasification plant. The major equipment items, the purge system and the safety shutdown system areessentially identical to the installations in the pilot units, with a few key modifications.This paper explains the problem of temperature measurement in entrained-flow gasifiers and describesthe pyrometer system developed by ChevronTexaco. It also goes on to describe the commercialprototype which has been built, and the commercial gasification plant field test, which is currently beingplanned.
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