Downdraft Biomass Fuel Gasifier

Abstract

The invention discloses a down-draft biomass fuel gasification furnace which belongs to the technical field of stoves. The down-draft biomass fuel gasification furnace comprises a gasification furnace body which is provided with a hearth and a fire grate at the bottom of the hearth, wherein a gas outlet cavity is formed between the inner wall of the gasification furnace body and the outer wall ofthe hearth; the hearth is provided with a drying region, a cracking region, an oxidation region and a reducing region from top to bottom; a gas outlet pipe, a gas guide mechanism and a carbon monoxide gas filtering mechanism which is used for filtering carbon monoxide gas and guiding the carbon monoxide gas to a combustor for combustion are arranged; one end of the gas outlet pipe is connected with the gasification furnace body and is communicated with the gas outlet cavity, and the other end of the gas outlet pipe is connected with the gas guide mechanism; and the gas guide mechanism is connected with the carbon monoxide gas filtering mechanism through a pipeline. The gasification furnace has the characteristic that: the internal diameter of the hearth is reduced to be less than the internal diameters of both the cracking region and the reducing region on the part corresponding to the oxidation region. The gasification furnace has the advantages of contributing to fully reducing the carbon dioxide gas into carbon monoxide gas, improving the purity of the carbon monoxide gas and preventing the hidden trouble of explosion of the gasification furnace body in case of backfire.

Description

technical field [0001] The invention belongs to the technical field of stoves, and in particular relates to a downdraft biomass fuel gasifier. Background technique [0002] The well-known situation is: on the one hand, the price of non-renewable resources such as coal, oil and natural gas is constantly increasing due to the increasing shortage, and the tension and sense of crisis of relying on natural resources are increasing because of the lack of ideal countermeasures for human beings; A large amount of available biomass energy is seriously wasted. The available biomass energy mentioned here is mainly but not limited to such as rice bran, rice straw, wheat straw, corn straw, soybean straw, sorghum straw and sawdust, etc. Especially in rural areas, people often see the phenomenon of farmers burning straw, which not only damages the environment, but also wastes resources. Despite efforts by the government and agricultural experts to encourage farmers to return straw to the...

AI Technical Summary

Problems solved by technology

This type of device can be seen in Chinese patent documents, typically such as the biogasifier recommended by the Chinese Invention Patent Publication No. CN101531925A (the application proposed by the inventor of the applicant). To the technical effect mentioned in line 22, but there are the following shortcomings: First, the furnace structure of the gasifier body is unreasonable, specifically manifested in that the surface area of ​​the oxidation zone and the reduction zone are the same, that is, equal, resulting in a reduction in the temperature of the reduction zone. High, but the temperature in the oxidation zone is not ideal (low), which is not conducive to the full reduction of CO 2 to CO, and the effect of CO gas production is poor. In addition, the oxidation zone and cracking zone basically tend to be equal in area, resulting in The boundaries between the cracking zone, oxidation zone and reduction zone are not obvious, so the tar substances produced in the drying zone and cracking zone cannot be fully oxidized in the oxidation zone, because, as a biogasifier, the temperature in the cracking zone should be 600-800 °C The temperature in the oxidation zone should be around 1200°C, the temperature in the reduction zone should be around 400-600°C, and the temperature in the oxidation zone is the highest, and the formation of this temperature curve relationship must be guaranteed by the structure of the furnace, and this temperature curve The relationship is crucial to the oxidation effect, that is to say, the tar material can be fully oxidized ideally. However, the furnace of the patent application is designed to make the areas of the cracking zone, oxidation zone and reduction zone tend to be equal, which is obviously not enough to ensure oxidation. The temperature in the zone meets the requirement of about 1200°C; secondly, the CO gas is not pure. The above-mentioned patent application uses a purification cylinder (built-in filter material) to purify and filter the CO gas. Since it is the only one-time filtration, the CO gas Water vapor and trace tar are difficult to filter to a satisfactory level, and trace tar will cause serious pollution to the burner pipeline, that is, block the burner pipeline; third, there are potential safety hazards. fire phenomenon, it is easy to cause an explosion and cause a serious accident

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