Fuel dealkalization device and method thereof and circulating fluidized bed gasification device and method thereof

Abstract

The invention discloses a fuel dealkalization device and a method and a circulating fluidized bed gasification device and a method thereof, and the fuel dealkalization device is a bubbling fluidized bed and comprises a fuel inlet which is located at the upper part of the fuel dealkalization device and is used for conveying fuel to the fuel dealkalization device; an auxiliary gasifying agent inlet positioned at the lower part of the fuel dealkalization device and used for conveying an auxiliary gasifying agent to the fuel dealkalization device, wherein the fuel and the auxiliary gasifying agent are subjected to dealkalization reaction under heating; a dealkalized solid fuel overflow port positioned at the upper part of the fuel dealkalization device and used for outputting the dealkalized solid fuel generated by the dealkalization reaction; and an alkali-rich fuel gas outlet is positioned at the upper part of the fuel dealkalization device and used for outputting alkali-rich fuel gas generated by the dealkalization reaction. The invention further provides the fuel dealkalization method and the circulating fluidized bed gasification device and the method thereof. The method solves the technical problem of slag bonding caused by high alkali metal content of the high-alkali coal, realizes safe and reliable utilization of the high-alkali coal, and has a wide market application prospect.

Description

technical field [0001] The invention relates to the technical field of fuel gasification, in particular to a fuel dealkalization device and method, and a circulating fluidized bed gasification device and method. Background technique [0002] Xinjiang has rich reserves of coal resources, with predicted reserves reaching 290 trillion tons, accounting for about 40% of China's total coal resources. Xinjiang will become China's energy succession area and strategic energy reserve area. The large-scale development and utilization of coal resources in Xinjiang plays a decisive role in China's energy strategy security and the leapfrog development of Xinjiang. [0003] Among the major coal fields in Xinjiang, the Zhundong coal field is currently the largest integrated coal field in China, with predicted reserves of up to 390 billion tons. Based on China's current annual coal consumption, the Zhundong Coalfield alone can be used nationwide for about one hundred years. Due to the spec...

AI Technical Summary

Problems solved by technology

Compared with other coal types in China, the Na content in Xinjiang Zhundong high-alkaline 2 O content is 3-15%, CaO content is 10-40%, Fe 2 o 3 The content of alkaline metals is between 7% and 20%. Such a high content of basic metals leads to the low melting temperature of coal ash in Zhundong coal in Xinjiang, which shows strong slagging and fouling characteristics during the thermochemical conversion process, which greatly limits its large-scale development and development. use

[0004] On the active boilers, it is impossible to realize the long-term and full-load operation of high-alkali coal

When purely burning high-alkali coal under high load, the heating surface of the boiler (water wall, partition screen, superheater, reheater, etc.) is prone to serious contamination, slagging, and ash accumulation, resulting in frequent overheating of some heating surfaces , pipe burst, flue blockage, coke loss, etc.

At present, power plants usually use low-load operation, blending other coal types, or adding additives to alleviate the above problems, but this leads to low utilization efficiency of high-alkali coal

[0005] On the active circulating fluidized bed gasifier, when purely burning high-alkali coal, there are no problems of contamination, slagging, and ash accumulation on the heating surface (air preheater, waste heat boiler, gas water cooler, etc.), which reflects that the circulating fluidized bed The gasifier has advantages in the utilization of high-alkaline coal, but the fuel of the active circulating fluidized bed gasifier is fed from the middle of the furnace, and the gasification agent is fed from the bottom of the furnace, so that the temperature at the bottom of the furnace is the highest, and the temperature gradually increases along the height of the furnace. The basic metals in the ash and slag are prone to low-temperature co-melting in the high-temperature zone at the bottom of the furnace, resulting in slagging at the bottom of the gasifier furnace, which is the bottleneck restricting the long-term stable operation of the circulating fluidized bed gasifier

Furthermore, the furnace bottom of the circulating fluidized bed gasifier is a dense-phase area, and the concentration of coal ash is high, which leads to the enrichment of alkali metals in the coal ash in this area, which increases the risk of slagging

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