Method for producing natural gas and coproducing fuel oil and aromatic hydrocarbons from coal through multilayer hydrogenation via pressurized moving bed

Abstract

The invention discloses a method for producing natural gas and coproducing fuel oil and aromatic hydrocarbons from coal through multilayer hydrogenation via a pressurized moving bed. According to theinvention, a pressurized moving-bed coal gasification bed is designed into a hydrogen gas section, an inter-section transition section and a water gas section from top to bottom; in the hydrogen gas section, multilayer hydrogenation is employed to optimize gas-solid countercurrent and H<2> / CH<4> partial pressure conditions and to increase the yield of coal tar and the reaction power of C and 2H<2>to CH<4>; discharged hydrocarbon-rich hydrogen gas is purified and separated to obtain coal tar, methane and hydrogen; the coal tar is subjected to hydrogenation reforming fractionation to prepare fuel oil and aromatic hydrocarbons; hydrogen is pressurized by a circulator and is then cyclically utilized; residual coke obtained after production of CH<1> is subjected to gasification, CO conversionand acid gas removal in the water gas section, and then becomes supplementary hydrogen for coal hydrogenation and coal tar hydrogenation; electricity for normal production is provided by self-producednatural gas in virtue of gas turbine power generation; power steam is provided by a gas turbine waste heat boiler; and a coal-fired steam boiler is not used. The method can greatly improve product energy efficiency and reduce water consumption, investment and environmental pollution.

Description

technical field [0001] The invention belongs to the field of energy chemical industry, and in particular relates to the energy conversion technology and equipment of coal-based natural gas and fuel oil. Background technique [0002] The current coal-to-oil and coal-to-natural gas, whether it is a two-step method of synthesizing oil and gas after coal gasification, or a one-step method of direct hydrogenation of coal to produce oil and gas, are all due to complex process routes and low energy conversion efficiency in the process , coal-to-oil is only 43%, consumption of standard coal is 3.4 tons / ton of oil, coal-to-natural gas is only 55%, consumption of standard coal is 2.3 tons / km 3 ; High equipment investment, coal-to-oil 160 billion yuan / 10 million tons, coal-to-natural gas 28 billion yuan / 4 billion m 3 ; Water resource consumption is high, coal-to-oil consumption is 7 tons / ton of oil, and coal-to-natural gas is 7 tons / km 3 ; Heavy environmental pollution, high cost of ...

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Problems solved by technology

[0005] The reasons for the low efficiency of the current one-step method of direct hydrogenation of coal to oil are that the conversion rate of carbon element is low, and the carbon content of the residue is as high as 40%, which needs to be reheated in a special gasifier to generate CO again; the second is the use of entrained flow bed Coal gasification hydrogen production, because in the entrained bed gasification process, the hydrogen element in the coal is in the form of hydrocarbons, and below 700 ° C, it will be pyrolyzed into gaseous hydrocarbons first, and then combined with the O in the gas stream. 2 Gas reacts to produce CO 2 and H 2 O releases heat, making the furnace temperature as high as 1300-1700°C. Therefore, a considerable part of the blast furnace temperature of the entrained bed is contributed by the combustion of hydrogen, which leads to a low molar fraction of hydrogen in the gas, and a particularly high content of CO, while CO must be It can be converted into hydrogen after conversion, that is, this hydrogen production process is essentially to burn off the H in coal first. 2 , and then use the C element in the coal to produce CO, and the CO can be transformed into H 2 ; The third is that the process pressure is as high as 20MPa, and the equipment investment is large. 2 no +2 There are also many disadvantages

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