Chemical looping combustion device and method for staged oxidation of solid fuel

Abstract

The invention discloses a chemical looping combustion device for solid fuel grading oxidation and a method thereof. The device is a circulating loop formed by an air reactor, an air cyclone separator, a fuel reactor, a fuel cyclone separator, a return feeder, a gasification reactor and an isolator. The method includes the steps that solid fuel is subjected to gasification reaction in the gasification reactor, generated gas fuel and oxygen carrier at a poor oxidation state are subjected to oxidation reaction, generated weak reduction gas enters the fuel reactor, and the generated weak reduction gas and oxygen carrier at an oxidation state are subjected to deep oxidation reaction, are converted into carbon dioxide and steam and are discharged; oxygen carrier at a reduction state in the air reactor and air are subjected to oxidation reaction to generate oxygen carrier particles at an oxidation state, and after being separated by the air cyclone separator, the oxygen carrier particles at an oxidation state enter the fuel reactor and are reduced to oxygen carrier at a poor oxidation state through weak reduction gas; after being separated by the fuel cyclone separator, the oxygen carrier at the poor oxidation state enters the gasification reactor through the return feeder and is reduced to the oxygen carrier at a reduction state through the solid fuel gasification products, and finally the oxygen carrier particles at a reduction state are returned to the air reactor through the isolator and are regenerated to form the oxygen carrier at the oxidation state.

Description

technical field [0001] The invention relates to a chemical looping combustion device and method for staged oxidation of solid fuel, in particular to a chemical looping combustion device and method for realizing staged oxidation of solid fuel, improving combustion efficiency, and achieving separation of carbon dioxide during combustion. Background technique [0002] Chemical looping combustion is a new type of combustion technology. The fuel does not burn directly in contact with the air, but through the alternate oxidation-reduction reaction of the oxygen carrier between the air reactor and the fuel reactor to realize the transfer of oxygen and complete the chemical energy of the fuel. The transformation process, the principle is: use metal oxides as oxygen carriers, the metal oxygen carriers in the reduced state are first contacted with air in the air reactor for oxidation reaction, and the metal oxygen carriers in the oxidized state are generated, and the oxygen carriers in...

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Problems solved by technology

[0003] In the gaseous fuel chemical looping combustion process, the conversion efficiency of the gaseous fuel in the fuel reactor is restricted by the reactivity of the oxygen carrier, the lower the reactivity of the oxygen carrier, the concentration of incompletely oxidized combustible gas in the outlet gas of the fuel reactor On the other hand, in the process of chemical looping combustion, the alternate oxidation-reduction reaction of the metal oxygen carrier between the air reactor and the fuel reactor will lead to sintering on the surface of the metal oxygen carrier particles, forming The dense surface layer reduces the reactivity of the oxygen carrier, so that the flue gas at the outlet of the fuel reactor contains more incompletely oxidized combustible gases, resulting in a decrease in the efficiency of chemical chain combustion

[0004] In the solid fuel chemical looping combustion process, the solid fuel in the fuel reactor first undergoes a gasification reaction with the gasification medium to generate gas fuel, and then the gas fuel reduces the metal oxide oxygen carrier to generate carbon dioxide and water vapor; and the metal oxide carrier Compared with the reduction process of oxygen, the gasification reaction of solid fuel is slow, which is the rate-controlling link of the entire solid fuel chemical chain combustion. There will be more fine coke particles that are not completely gasified and are directly carried away by the airflow from the fuel reactor. Resulting in a reduction in the combustion efficiency of solid fuel chemical loops

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