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Show UTILITIES DESCRIPTION During various tests natural gas was available from the Apopka pipe line which has an average specific gravity of 0 . 5836 and contains 95.31% methane (CH4). The oxygen was supplied from cylinders at 99% purity. The various gas flow rates were measured using orifice flow meters. TEST RESULTS The low NOx method of natural gas firing using the CTI cracker has undergone nine campaigns till mid August. The overall effort was directed in two general categories: 1. Improvement in the cracker hardware design including oxy/fuel burner design; flow configurations; measurement and data acquisition methods. 2. Establishment of appropriate operating variables including burner flow rates, stoichiometric ratios, cracking gas flow rates, operating temperatures, theoretical (computer) analysis of the experimental data for the mass, energy, and soot estimates. A typical data covering the last tests (Campaign #9) is listed in Table 1. The data indicate two separate tests, 9 -10 and 9 -12 . The tests were conducted using an oxy/fuel burner firing axially, whereas the cracking gas was introduced through a downstream 3/8" port. Prior to cracking, the combustion chamber was heated to a uniform temperature of 2100° F . The Table-l shows various chamber temperatures, metered mass flows, calculated flows based on mass balances, measured soot and yiel~ on weight basis, mass flow ratios and cracked gas analysis based on Orsat measurements. The maj or difference between tests 9-10 and 9-12 is the use of air to enhance cracking in test 9-12, where the air was tangentially introduced through a 3/8" port. The Campaign #9 indicated without doubt that there are two major reforming reactions (steam-methane and C02-methane) taking place in the combustion chamber, where the steam (H20) and C02 are the products of combustion from oxy/fuel burner. It is believed that these endothermic reactions take preference over the thermal cracking (methane dissociation) reaction and in turn use up all the available heat for producing reformed gases CO and H2; thus, further slowing the thermal cracking reaction and eventually bring the overall combustion chamber temperature down . In order to defeat this reforming process or retarding to a certain extent, some form of inert media is necessary. This made us try air in the test 9 -12, through a 3/8" downstream port. The nitrogen in air acts as a retardant for reforming and also supplies the necessary heat for -4- |