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Combustion of coal-water and petroleum coke-methanol-water mixtures in a firetube boiler

Conference ·
OSTI ID:5755835

Tests have been conducted to evaluate the combustion characteristics of slurry fuels in an oil-designed 100-hp firetube boiler. Results of tests with coal-water and coal-methanol-water mixtures have been reported in earlier symposia. Most recently, a 271-hour duration test at full boiler load (3450 lb/hr steam output) was conducted with a commercial coal-water mixture (CWM) to determine the behavior of ash accumulation in the firetube boiler and the need for installing ash removal equipment. A steady-state layer of ash deposits was ultimately established in the boiler firetube and gas passes, which permitted sustained boiler operation. The carbon conversion and boiler efficiencies fluctuated within narrow ranges but without a definite decreasing trend with time. The pressure drop across the boiler increased only slightly over the duration of the test. These results suggest that long-term operation of package industrial firetube boilers on CWM is possible. Exploratory tests have also been conducted to determine the feasibility of firing petroleum coke-water mixtures in the firetube boiler and to determine the minimum requirements for combustion air preheat or methanol to maintain a stable combustion flame. Petroleum coke-water mixtures containing 60 to 64% low-volatile coke could not be fired satisfactorily without natural gas support. A petroleum coke-methanol mixture containing 53% coke was burned without gas support using ambient-temperature and 500/sup 0/F combustion air. The highest carbon conversion efficiency achieved was 92%. The carbon conversion efficiencies obtained with petroleum coke-methanol-water (PCMW) mixtures were generally lower than those obtained with coal-methanol-water mixtures under similar operating conditions. 6 refs., 6 figs., 8 tabs.

Research Organization:
USDOE Pittsburgh Energy Technology Center, PA
OSTI ID:
5755835
Report Number(s):
CONF-840637-1; ON: DE85013457
Country of Publication:
United States
Language:
English