Characterization of Nitrogen Compounds in Tar Produced from Underground Coal Gasification

King, S.B.; Brandenburg, C.F.; Lanum, W. J.

doi:10.1080/00908317808945982

Cited by 6 publications

(2 citation statements)

References 2 publications

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“…Over 38 days the average heating value was 1 350 kcal/m3 (higher heating value) with very stable operation. The UCG SYStem was operated at relatively high flow and production rates compared to previous tests; these operating conditions enhanced product gas heating value (Fiwher and Schrider, 1975;Brandenburg et al, 1975;King et al, 1975;Schrider and Fischer, 1975). The test was terminated before the combustion front reached the production well.…”

Section: Laramie Energy Research Centermentioning

confidence: 97%

Underground coal gasification

1978

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Underground coal gasification (UCG) is a method whereby the mining and conversion of coal are accomplished in a single step. Many field tests of UCG have been operated worldwide since the 1930's with varying degrees of success; based on this experience (especially in the USSR and United States), a field design which is applicable to a wide range of geological conditions and coal properties has evolved. This review discusses the rationale of this design and provides a physicochemical interpretation for the operation of a UCG system. Pertinent field and laboratory results as well as formal mathematical models of an in situ gasifier are evaluated as part of the analysis. SCOPEThere are presentIy many coal reserves in the world which are not economically recoverable using conventional mining techniques. Underground (in situ) coal gasification offers a potentially economic means of extracting the energy content from such coals while, at the same time, eliminating many of the health, safety, and environmental problems of deep mining of coal. A significant amount of field testing of underground coal gasification, especially in the USSR, has occurred in the past 50 yr, and the low Btu gas process is currently in commercial use at several sites in the USSR, UCG is presently of great interest in North America, where seven field tests are in operation. Recent cost estimates for producing low, medium, and high Btu gas by UCG show that it is more economically attractive than conventional mining followed by first generation surface gasification for thick western coal seams between 200 and 2 000 ft deep.The development and utilization of UCG in this country has, however, been hindered by a number of unsuccessful field tests, incomplete knowledge about Russian UCG technology, and a general lack of understanding about field design principles and the physicochemical processes involved. However, recent translations of the Russian technical literature have provided a significant body of information about Russian operating experience for a wide variety of geological conditions and coal properties. In addition, the U.S. Department of Energy has operated extremely successful field tests on Wyoming coal in the last 4 yr. Hence, a nominal field design can be performed using existing technology. Commercialization of UCG in the United States and Canada awaits economic optimization of the process design as well as a clearer picture of the role and economics of alternative energy sources, especially coal, as substitutes for oil and gas.The objective of this review is to present the basic field design for UCG and the logic behind it and to provide an interpretation of the chemistry and physics of UCG. Ultimately, such an analysis is the basis for evaluating the technical and economic feasibility of a candidate site for underground coal gasification. CONCLUSIONS A N D SIGNIFICANCEThe design of an underground coal gasification (UCG) system is a formidable one in view of the performance requirements, since there are very few adjustable paramete...

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Section: Laramie Energy Research Centermentioning

confidence: 97%

Underground coal gasification

1978

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“…The literature − also contains studies of the same issues, and good progress has been achieved. However, this research on groundwater contamination induced by underground gasification was limited to monitoring, general analysis, or simple mathematical description or simulation; an integrated and quantitative study is imperative.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Contaminant Transport in Underground Coal Gasification

Yang

Xing

2008

Energy Fuels

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In order to study and discuss the impact of contaminants produced from underground coal gasification on groundwater, a coupled seepage-thermodynamics-transport model for underground gasification was developed on the basis of mass and energy conservation and pollutant-transport mechanisms, the mathematical model was solved by the upstream weighted multisell balance method, and the model was calibrated and verified against the experimental site data. The experiment showed that because of the effects of temperature on the surrounding rock of the gasification panel the measured pore-water-pressure was higher than the simulated one; except for in the high temperature zone where the simulation errors of temperature, pore water pressure, and contaminant concentration were relatively high, the simulation values of the overall gasification panel were well fitted with the measured values. As the gasification experiment progressed, the influence range of temperature field expanded, the gradient of groundwater pressure decreased, and the migration velocity of pollutant increased. Eleven months and twenty months after the test, the differences between maximum and minimum water pressure were 2.4 and 1.8 MPa, respectively, and the migration velocities of contaminants were 0.24-0.38 m/d and 0.27-0.46 m/d, respectively. It was concluded that the numerical simulation of the transport process for pollutants from underground coal gasification was valid.

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