Supercritical water coal gasification device and method

Abstract

The invention discloses a supercritical water coal gasification device, and a method. The supercritical water coal gasification device comprises a water electrolysis unit, a gasification reactor, a waste heat recovery unit, and a deslagging unit; the water electrolysis unit is arranged at the middle lower part of the supercritical water coal gasification device, and is used for electrolysis of water into hydrogen gas and oxygen gas; hydrogen gas is directly introduced into an outlet of the gasification reactor through a pipeline for mixing with a gasification product, and oxygen gas is introduced into the gasification reactor directly; supercritical water coal slurry and high temperature water are introduced into the gasification reactor for gasification reaction with oxygen gas provided by the water electrolysis unit, pollutants such as sulfur and heavy metals are precipitated to the bottom of the reactor with coal ash, and are discharged through the deslagging unit; gasification reaction products are discharged through the top of the reactor, is mixed with the hydrogen gas from the water electrolysis unit, and then is delivered into the waste heat recovery unit with the hydrogen gas, is cooled, and then is discharged out from the supercritical water coal gasification device. The supercritical water coal gasification device is capable of realizing coal clean high efficiency conversion; synthetic gas heat value is high; and compared with conventional coal gasification method, the advantages are that: the structure is simple, and economical and environment protection performance is excellent.

Description

technical field [0001] The invention relates to the technical field of coal gasification and hydrogen production by electrolysis of water, in particular to a supercritical water coal gasification device and method. Background technique [0002] The critical point of supercritical water is 22.13MPa, 374.15°C. Supercritical water has many special properties. It is a uniform, non-polar solvent with high diffusivity and high transfer characteristics. As a chemical reaction medium, it has good transferability and solubility. Organic matter and some permanent gases (nitrogen, hydrogen, oxygen, etc.) Control of physical properties of supercritical water. [0003] Because supercritical water has these excellent properties, supercritical water gasification of organic matter is becoming a clean and efficient way of energy conversion and clean treatment of organic waste, which has attracted more and more attention. [0004] At present, the organic matter of supercritical water gasif...

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Problems solved by technology

[0005] Supercritical water coal gasification is an endothermic process, and the gasification process needs to absorb a large amount of heat. For a high-temperature and high-pressure gasification device, it is difficult to supply heat to the gasification device from the outside

The introduction of an oxidant (such as oxygen or air) can provide heat for the gasification process through the heat release of the oxidation reaction. However, direct introduction of air will dilute the reaction, reduce the gasification rate, and take away a large amount of heat, making the gasification reaction more efficient. In addition, the synthesis gas will be diluted, so that the calorific value of the synthesis gas will be reduced. Compressing the air to the pressure corresponding to the supercritical water state will consume a lot of mechanical energy or electrical energy; and the oxygen will be consumed in the additional air separation unit. A lot of energy, compressing oxygen also consumes a lot of electricity

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