Coal pyrolyzed

The effect of hydrogen on coal pyrolysis can further be illustrated by Figure 4, where we compared derivative thermograms of Wyoming coal pyrolyzed at 200 psig of N2 and 200 psig of H2 at the same heating rates (20 C/min). The secondary hydropyrolysis peak... 

Figure 4. A comparison of thermograms between Wyoming coal pyrolyzed in 200 psig N2 and 200 psig H2 at 20 C/min.

Nature of the Free Radicals in Coals, Pyrolyzed Coals, Solvent-Refined Coal, and Coal Liquefaction Products... 

Characterization of the stable radicals present in coals, pyrolyzed coals, and liquefaction and other coal conversion products is a necessary first step toward elucidating the role of radicals in coal liquefaction. Electron... 

Figure 22, High-resolution spectra of gases from coal pyrolyzed at 1200 C and 800°C, Spectra are obtained in a room temperature cell. (Reproduced, with permission, from Ref. 25.)...

The proposed advanced PFBC cycle will permit a turbine inlet gas temperature of over 1535 K (2300°F) by burning a fuel gas produced by pyrolysis of the coal feed. Because the turbine fuel gas must be practicaUy particulate free, it passes through HTHP filters before combustion. The char residue from the pyrolyzer may be burned in a circulating AFBC or PFBC to produce steam for power or heating. The efficiency attainable in an advanced PFBC plant may be as hi as 50 percent (HHV basis). 

Beyond the ATS program, the DOE is looking at several new initiatives to work on -with industry. One, Vision 21, aims to virtually eliminate environmental concerns associated with coal and fossil systems while achieving 60 percent efficiency for coal-based plants, 75 percent efficiency for gas-based plants, and 85 percent for coproduction facilities. Two additional fossil cycles have been proposed that can achieve 60 percent efficiency. One incorporates a gasifier and solid oxide fuel into a combined cycle the other adds a pyrolyzer with a pressurized fluidized bed combustor. Also under consideration is the development of a flexible midsize gas turbine. This initiative would reduce the gap between the utility-size turbines and industrial turbines that occurred during the DOE ATS program. 

The earliest practical production of synthetic gas (syngas) is reported to have taken place in 1792 when Murdoch, a Scottish engineer, pyrolyzed coal in an iron retort and then used the product, coal gas, to light his home.1... 

Figure 3. Molecular weight distributions of pyrolyzates in six successive temperature intervals during Py-FIMS analysis of Pittsburgh 8 coal.

Since only relatively simple equipment is required, it should prove feasible to flash-pyrolyze the coal at the generating station or at the mine at which it is produced, and to transport the primary liquids from several operations to a large central upgrading facility. In Alberta alone, where coal consumption by electric utilities is expected to climb from an annual rate of 6.5 million tons In 1977 to 16-17 million tons in 1985 and... 

Acetylene can be produced by pyrolysis of coal and by fuel-rich combustion of alkanes, a process that also produces soot or carbon black, the major ingredient in automobile tires. Acetylene can also be made with nearly stoichiometric efiiciency by decomposing calcium carbide, CaC, which is produced by pyrolyzing limestone and coke,... 

Once the volatile prodiicts have been pyrolyzed, one is left with a material that is mostly carbon, and these are called coke (from coal) and charcoal (from wood). Coke was of course used in blast furnaces to make iron (the volatiles would make the process less reproducible in reducing Fc203) by our ancestors, while charcoal was used in soap (mainly the alkalis in the ash) and as an adsorbent. 

Ammonia evolved in coal gasification usually is washed out with water, taking with it H2S, CC>2, and HCN. Phenols and basic nitrogen compounds are also present if a pyrolyzing gasifier is used. Such water usually is purified by steam stripping, which liberates a vapor mixture of NH3, H2S, CO2 with some HCN. Usable ammonia may be separated by fractional distillation (the WT process) or by differential absorption (the Phosam process) in these cases a rich H2S is prepared for Claus processing. 

It was observed earlier (17, 18, 22) that the yield of methane from pyrolyzing dehydrogenated coals (including the methane evolved during de-... 

The above conclusions are supported by the results obtained by pyrolyzing reduced coals (Table V). Although the hydroaromatic content of the coals was doubled or even quadrupled by reduction, the yield of methane (including small proportions of ethane) from carbonizing the reduced samples was about the same as from untreated coals. In one case, however, the yield of... 

As an extension of the proximate analysis or coal assay, it is worthy of note that new methods continued to be developed. For example, thermogravimetric analysis has been extended to cover determinations of volatile matter (as well as determination of moisture and ash) in coal and coke. These constituents can be measured by pyrolyzing the samples in oxygen and air, and the weight loss at prescribed temperatures was measured by using a thermobalance. 

In the Hybrid gasification process, a slurry of coal and residual oil is injected into the gasifier where it is pyrolyzed in the upper part of the reactor to produce gas and chars. The chars produced are then partially oxidized to ash. The ash is removed continuously from the bottom of the reactor. 

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