US 4,597,776 A · Hydropyrolysis process

Abstract

An improved process for producing a methane-enriched gas wherein a hydrogen-deficient carbonaceous material is treated with a hydrogen-containing pyrolysis gas at an elevated temperature and pressure to produce a product gas mixture including methane, carbon monoxide and hydrogen. The improvement comprises passing the product gas mixture sequentially through a water-gas shift reaction zone and a gas separation zone to provide separate gas streams of methane and of a recycle gas comprising hydrogen, carbon monoxide and methane for recycle to the process. A controlled amount of steam also is provided which when combined with the recycle gas provides a pyrolysis gas for treatment of additional hydrogen-deficient carbonaceous material. The amount of steam used and the conditions within the water-gas shift reaction zone and gas separation zone are controlled to obtain a steady-state composition of pyrolysis gas which will comprise hydrogen as the principal constituent and a minor amount of carbon monoxide, steam and methane so that no external source of hydrogen is needed to supply the hydrogen requirements of the process. In accordance with a particularly preferred embodiment, conditions are controlled such that there also is produced a significant quantity of benzene as a valuable coproduct.

Claims13

Dependent claims

A process for producing methan by reacting a hydrogen-deficient carbonaceous material with a hydrogen-containing pyrolysis gas having a composition selected and controlled so that no external source of hydrogen is needed to provide the hydrogen requirements for the overall process, which comprises the sequential steps of:

(a) introducing said pyrolysis gas at an elevated temperature and pressure and said carbonaceous material into a single pyrolysis zone of an entrained flow reactor (10) to react to form a product gas mixture including methane, carbon monoxide and a reduced content of hydrogen relative to that in said pyrolysis gas;
(b) reacting a part of the carbon monoxide in said product gas mixture with a first controlled amount of steam in a water-gas shift reaction zone (18) sufficient to produce hydrogen in an amount substantially equal to the hydrogen consumed in the overall process;
(c) withdrawing from said water-gas shift reaction zone a shifted gas mixture containing additional hydrogen and introducing said shifted gas mixture into a gas separation zone (30);
(d) separating the shifted gas mixture in said gas separation zone into (1) a product comprising methane, and (2) a recycle gas comprising hydrogen, carbon monoxide and methan;
(e) introducing said recycle gas from step (d) (2), a controlled amount of an oxygen-containing gas and a second controlled amount of steam into a gas treatment zone (44) for partial oxidation of the recycle gas to produce said pyrolysis gas having said elevated temperature for introduction into said entrained flow reactor (10);
and
(f) controlling steps (b), (d) and (e) to obtain, under steady-state conditions, a composition of the pyrolysis gas wherein hydrogen is the principal constituent and the remainder consists essentially of a monor amount each of carbon monoxide, steam and methane so that no external source of hydrogen is needed to provide the hydrogen requirements for the overall process.

4 more elements

A process for producing methane and benezene by reacting a hydrogen-deficient carbonaceous material with a hydrogen-containing pyrolysis gas having a composition selected and controlled so that no external source of hydrogen is needed to provide the hydrogen requirements for the overall process, which comprises the sequential steps of:

(a) introducing said pyrolysis gas consisting essentially of from about 1 to 10% carbon monoxide, 3 to 20% methane, 6 to 30% steam and a balance of hydrogen, at an elevated temperature and pressure, and said carbonaceous material into a single pyrolysis zone of an entrained flow reactor (10) to react said hydrogen-deficient carbonaceous material with said pyrolysis gas at a temperature within the range of from about 760.degree. C. to 1260.degree. C., at a pressure of from about 3.5 to 10.5 megapascals and for a time of from about 2 to 10 seconds, to form a product gas mixture including methane, benzene, carbon monoxide and a reduced hydrogen content relative to that in said pyrolysis gas;
(b) reacting a part of the carbon monoxide in said product gas mixture with a first controlled amount of steam in a water-gas shift reaction zone (18) sufficient to produce hydrogen in an amount substantially equal to the hydrogen consumed in the overall process;
(c) withdrawing from said water-gas shift reaction zone a shifted gas mixture contaiing additional hydrogen and introducing said shifted gas mixture into a gas separation zone (30);
(d) separating the shifted gas mixture in said gas separation zone into (1) a product comprising methane and benzene, and (2) a recycle gas comprising hydrogen, carbon monoxide and methane;
(e) introducing said recycle gas from step (d)(2), a controlled amount of an oxygen-containing gas and a second controlled amount of steam into a gas treatment zone (44) for partial oxidation of the recycle gas to produce said pyrolysis gas having said elevated temperature for introduction into said entrained flow reactor (10);
and
(f) controlling steps (b), (d) and (e) to obtain, under steady-state conditions, a composition of the pyrolysis gas mixture of step (a) so that no external source of hydrogen is needed to provide the hydrogen requirements for the overall process.

4 more elements

Dependencies are inferred from the claim text.

Hydropyrolysis process

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Hydropyrolysis process

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Abstract

Claims13