Gas: heating and illuminating – Processes – Coal and water
Patent
1980-04-29
1982-06-29
Kratz, Peter F.
Gas: heating and illuminating
Processes
Coal and water
48210, 252373, 376325, C10J 310, C10J 318
Patent
active
043370675
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a plant for generating methane or synthesis gas from carbon-containing materials, especially by utilizing nuclear energy. In this process, a first part of the carbon is reacted with hydrogen to methane in a hydrogenating gasifier and a second part of the carbon is reacted with steam to synthesis gas in a steam gasifier. These plants furnish either methane (CH.sub.4) or synthesis gas as a mixture of H.sub.2 and CO. This plant is suitable particularly for coal grades which do not react readily, such as hard coal.
In "Chemie-Ingenieur-Technik" 1974, page 938, especially in FIG. 1 as well as page 941, especially FIG. 2, a schematic process is described in each for producing methane via steam gasification of coal. On page 937, new processes of gasification of coal to methane by hydrogenation are mentioned. Both processes, however, have a considerable disadvantage. With gasification by hydrogenation, complete reaction of the coal is not attainable, because a long dwelling time of the carbon is required to get more complete reaction and for practical purposes the gasifier has limited dimensions. The residual coke obtained in the hydrogenating-gasification contains, in addition to the ash, about 30 to 45% of the carbon charged-in. In the steam gasification, on the other hand, the charged-in carbon can be gasified almost without residue. This process takes place only at high temperatures (bituminous coal, 790.degree. C.; lignite, 630.degree. to 660.degree. C.), and only the upper temperature range of the heat released in the reactor can be utilized for the gasification. In the case of a pure steam gasification process, the residual heat can essentially only be used for generating steam and therefore for generating power because only a small part of this steam can be used in the process.
In the report ORNL/TM-5242 (Oak Ridge National Laboratory, November 1976) page 82, a plant is shown in which carbon is reacted to methane by means of nuclear heat. The coal is first dried, then gasified by hydrogenation, and the residual coke is converted in a steam gasifier into synthesis gas. Part of the methane produced with added hot steam is reacted in a methane cracking furnace (called a reformer there) to synthesis gas. This arrangement, however, has the following further disadvantages: The process heat exchangers arranged in a primary or also in a secondary helium loop are very expensive. Heilum carrying piping and apparatus place increased requirements on the tightness which is necessary to prevent undesired substances from penetrating into the primary loop and either have corrosive effects there, or cause undesirable deposits which become activated in such a manner that they cause trouble at other places. In addition, all process heat exchangers heated with pure helium have the disadvantage that helium, being a single-atom gas, gives off no radiation heat, which is disadvantageous particularly at the high temperatures here. Consequently, the velocity of the helium would have to be increased in order to increase the heat transfer through convection. This increases the pressure loss, or else the heating surfaces would have to be enlarged.
In German Published Non-Prosecuted Application No. 25 53 506.2, a plant for producing methane or synthesis gas from carbon-containing materials by means of a nuclear reactor is described, wherein part of the carbon-containing material is converted into synthesis gas, with the addition of steam and at high temperature, in a steam gasifier. This plant has two reactor cooling loops; in a first cooling loop is arranged the steam gasifier and in a second cooling loop is arranged a reformer known per se in which part of the methane produced is cracked at high temperature to hydrogen, which latter is used for the hydrogenating-gasification of another part of the carbon-containing material. This two-stage gasification combines in an advantageous manner the following requirements: low coal consumption, complete gasification of the coal, inclusion of the entire nuclea
REFERENCES:
patent: 1790853 (1931-02-01), Casale
patent: 2631930 (1953-03-01), Peters
patent: 3252773 (1966-05-01), Solomon et al.
patent: 4005045 (1977-01-01), Hoese
patent: 4095959 (1978-06-01), Kunstle et al.
Oak Ridge National Laboratory Report TM-5242, Nov. 1976, p. 82, Spievak et al.
Vergasung Von Kohle mit Kernreaktorwarme, Juntgen et al., Chemie-Inglmieur-Technik, 1974, pp. 937-943.
Jager Walter
von Waclawiczek Herbert
GHT Gesellschaft fur Hochtemperaturreaktor-Technik mbH
Greenberg Laurence A.
Kratz Peter F.
Lerner Herbert L.
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