Mild gasification in transport reactors
Forty-five runs were made varying coal type (lignites, subbituminous, and bituminous), temperature (550, 600, 650 and 700[degrees]C), pressure (1 atmosphere to 80 psig), pyrolyzing gas (nitrogen or steam), and residence time (2.5 sec to 15 sec). Some typical results are summarized in Table 2 which presents the pyrolysis product distribution between char, tar, gas, water, and missing as well as the gas composition. Percent tar yield quantities are based on a Dry Ash Free (DAF) weight percent of total coal fed into the reactor. The component designated missing is a combination of collection variations and light tar molecules which evaporate during the collection process. Some very light tars (paraffins and olefins in the gas analysis) are analyzed and included with the gases sampled in the FTIR cell. The tar yields shown in this report, which range from 5% for lignite at high pressure to 30% for bituminous coals at one atmosphere, represent a minimum value; the actual tar yield should be the missing plus those tars included in the gas analysis. The TG-FTIR summary of tars evolved, Table 1, may give a better indication of the total tar yield. However, the TG-FTIR does not pyrolyze coal under the same conditions as the HTR. As shown in Figs. 4--6 and Table 2, pyrolysis tar yields for all coals have an optimum temperature of approximately 600[degree]C using a 2.5 sec resident time. The yields decrease with increases in pressure. Lower heating rates and longer residence times usually lead to lower tar yields. The degree to which tar yields decrease depends on the amount of pressure and the reaction temperature. There were no significant differences in tar yield when nitrogen or steam was used as the carrier gas.
- Research Organization:
- Advanced Fuel Research, Inc., East Hartford, CT (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG05-90ER80877
- OSTI ID:
- 6987488
- Report Number(s):
- DOE/ER/80877-93/C0116; CONF-920951--28; ON: DE93002603
- Country of Publication:
- United States
- Language:
- English
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014000 -- Coal
Lignite
& Peat-- Combustion
CARBONACEOUS MATERIALS
CHARS
CHEMICAL REACTIONS
CHEMICAL REACTORS
COAL
COAL RANK
COAL TAR
COMBUSTION
COST
DECOMPOSITION
EFFICIENCY
ELEMENTS
ENERGY SOURCES
EQUIPMENT
FOSSIL FUELS
FUELS
GAS TURBINES
MACHINERY
MATERIALS
NITROGEN
NONMETALS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXIDATION
POWER GENERATION
PRESSURE DEPENDENCE
PYROLYSIS
PYROLYSIS PRODUCTS
STEAM
STEAM TURBINES
TAR
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES
TURBINES
TURBOMACHINERY
YIELDS