Gas Generator Research and Development, BI-GAS Process. A Study of Flame Detection Devices in a High Pressure Gasifier

摘要

A principal feature of the BI-GAS Pilot Plant is the 2-stage, entrained-bed, high pressure (1500 psig max), oxygen blown, and ash slagging gasifier unit constructed by the Babcock and Wilcox Company. The gasifier is designed such that its lower region (Stage I) is the combustion zone where oxygen and steam contact and react with recycled char. As with other combustion systems, provisions must be made to initiate combustion at start-up, to reinitiate combustion in case of a process upset where combustion is lost, and to continuously monitor the presence of combustion. An ignition system had to be developed, capable of reliable and repeated operation at pressures up to 1500 psi in a methane-rich or otherwise reducing atmosphere. The initial development work was done by Babcock and Wilcox and included development of both the ignitor system and the flame confirmation system. One of the problems encountered in operating the BI-GAS Pilot Plant has been unreliable flame detection of the pilot burners in the high pressure gasifier. Since the operation of the slag tap burner (STB) and the slag heating burner (SHB) are prerequisites for the gasifier start-up as well as prolonged operation, verification of a flame is important to the pilot plant operation. The original Bailey Meter Company's Flamon ultraviolet detector had not provided that reliability as evidenced by numerous shutdowns of the gasifier.This report presents the findings of a study aimed at evaluating several alternate commercially available flame detection devices with hopes of finding one capable of doing the job. An infrared Fireye flame detector made by Electronics Corporation of America showed very encouraging results. As a result, the Fireye was recommended and installed as the flame detection device on both pilot burners has proven superior to any of the ultraviolet detectors. (ERA citation 05:011059)