Biomass three-section type entrained flow bed gasification technology with function of waste heat utilization

Abstract

The invention discloses a biomass three-section type entrained flow bed gasification technology with the function of waste heat utilization, which relates to the technical field of energy chemical technology. The gasification technology is realized in a way that: carbon powder, pyrolysis gas and oxygen, which are generated after the biomass is pyrolyzed, enter an entrained flow bed to obtain synthetic gas through gasification, and the energy of the gasification waste heat is transferred to water by a heat exchanger of a gasifier, thereby producing superheated steam. The gasifier of the entrained flow bed is divided into a high-temperature entrained flow bed section, a high-temperature heat exchanger section and a low-temperature heat exchanger section, wherein the high-temperature entrained flow bed section adopts a dry ash extraction entrained flow bed gasification technology, and the temperature of the synthetic gas at the outlet is 1280-1320 DEG C; at the high-temperature heat exchanger section, the temperature of the synthetic gas at the inlet is 1280-1320 DEG C, the temperature at the outlet is 580-600 DEG C, a shock chamber and a high-temperature superheater are arranged in the high-temperature heat exchanger section, and the synthetic gas enters the shock chamber at the temperature of 1000-1100 DEG C and leaves at the temperature of 700-800 DEG C; and at the low-temperature heat exchanger section, the temperature of the synthetic gas at the inlet is 580-600 DEG C, the temperature of the synthetic gas at the outlet is 220-230 DEG C, and a low-temperature superheater and a coal economizer are arranged in the low-temperature heat exchanger section. The invention is used for high-efficiency gasification of biomass.

Description

technical field [0001] The biomass three-stage entrained gasification technology with waste heat utilization of the present invention relates to the technical field of energy and chemical engineering; in particular to the technical field of biomass thermochemistry; especially to the technical field of biomass gasification technology; specifically to the utilization of waste heat The technical field of biomass entrained bed gasification. Background technique [0002] Plants in biomass are organic substances generated by absorbing carbon dioxide in the air through photosynthesis, which are widely distributed, available in large quantities, and are the only renewable natural raw materials that contain hydrocarbon components and heat energy and can be stored; Substances for energy utilization and chemical production, with CO 2 Characterized by zero emissions. With the decrease of traditional fossil energy reserves and the environmental pollution caused by the use of fossil ene...

AI Technical Summary

Problems solved by technology

[0008] First, entrained bed gasification has strict restrictions on the particle size of raw materials. The raw materials entering the entrained bed need to be ground into ultrafine particles. The raw material is ground to meet the particle size required for entrained bed operation, which makes it impossible to directly use biomass raw material for entrained bed gasification

[0009] Second, the outlet temperature of the entrained bed synthesis gas is very high, generally above 1300°C, and the application of the synthesis gas needs to be purified or converted, which requires the temperature of the synthesis gas to be reduced to about 250°C. If not fully utilized, it will lead to inefficiency of the entire gasification system

[0010] Third, due to the high content of alkali metals (K, Na) in biomass raw materials, they exist in gaseous form at high temperature, and during the cooling process of syngas, they will condense into solid and adhere to On the wall of heat exchanger tubes, causing alkali metal corrosion and slagging of the tubes on the heating surface and blocking the synthesis gas channel

[0011] Fourth, since the synthesis gas obtained from biomass gasification has carbon evolution reaction during the cooling process, a severe carbon evolution reaction will also occur in a certain temperature range, and the CO in the synthesis gas reacts to form CO 2 and carbon black, resulting in a decrease in carbon conversion efficiency and gasification efficiency. At the same time, due to the deposition of carbon black on the metal surface of the heat exchanger tube, it causes metal ashing and metal corrosion.

But for problems 2, 3, and 4, all the technologies for biomass entrained bed gasification in the world at present either do not make good use of the waste heat of synthesis gas, or do not solve the problem of metal ashing in the carbon evolution reaction, or do not have a better solution. Methods to control alkali metal corrosion and slagging

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