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Show INTRODUCTION An entrained coal gasifier is one of the more promising methods of converting coal into a more useful ana environmentally acceptable fuel. The entrained gasifier provides high material throughput and is relatively insensitive to coal type, gasifying caKing and non-caking coals. Entrained coal gasification is a relative new technology, when compared to the fixed bed reactors whose foundations date back to about 1790 (1). Bissett (2) has provided an excellent review of the development of the various entrained flow processes, which began in the late 1950's. Even though entrained gasifiers have been under development for only about 25- 30 years, little is known about the local details of mixing ana reaction within the reactor, especially as it affects the formation of desirable gasification products and undesirable sulfur and nitrogen pollutants. An investigation of the mixing and gasification of finely pulverized coal in an entrained flow reactor has been underway at this Laboratory for several years. Earlier results (3-5) were not as reliable and accurate as desired because mechanical problems gave uncertain feed rates, especially coal, and because the analytical techniques used to measure the reaction products, especially sulfur and nitrogen pollutants, were not well developed. Recently, considerable effort has been expended to improve the mechanical reliability of the gasifier, and the accuracy of the test results. In addition, earlier test results (3,4) gave relatively low carbon conversion (40-70%) aepenaing on oxygen/coal and steam/coal ratios. The introduction of all of the oxgyen in the primary stream along with the coal was found to be a major factor in increasing carbon conversion (5). Recent test results have shown that this effect occurs, but only when accompanied by high temperature wall sections in the region near the discharge of the oxygen/coal primary stream into the reactor (6). The objectives of this study were to 1) obtain detailed local samples of gasification products, including the char, and sulfur and nitrogen pollutants, 2) identify the important reaction processes, and 3) provide a detailed local data base for comparison and validation of the two-dimensional entrained coal gasification model developed at this 6-2 |
