Semi-tower type medium-temperature separation biomass circulating fluidized bed boiler

Abstract

The invention relates to a semi-tower type medium-temperature separation biomass circulating fluidized bed boiler, composed of a front shaft, a middle gas-solid separating and recycled material returning unit, and a tail flue, wherein the front vertical well comprises a hearth, a convection shaft and a smoke reversing chamber; the middle gas-solid separating and recycled material returning unit comprises a gas-solid separating device, a returning riser and a returning device; a super-heater, an economizer and an air pre-heater are arranged along a smoke flowing direction in the tail flue; a lower portion of the hearth is provided with 2 to 3 layers of secondary air along a height direction; an upper portion of the hearth is provided with a convection heated surface in the convection shaft; the hearth, the convection shaft, the smoke reversing chamber, the gas-solid separating device, the returning riser and the returning device compose a main circulation loop. According to the invention, adaptability of fuels is wide; combustion efficiency is high; abrasion and corrosion for the heated surface is poor; temperature of the smoke at an inlet of the gas-solid separating device is within a range of 400-750 degrees centigrade so as to effectively prevent slagging, slag hanging, dusts gathering, ashes blocking, bed materials blocking and returning device blocking in the boiler.

Description

technical field [0001] The invention relates to a circulating fluidized bed boiler, in particular to a half-tower type mid-temperature separation biomass circulating fluidized bed boiler. Background technique [0002] Biomass energy is energy converted from natural plants, feces, and urban and rural organic waste. It is an energy form in which solar energy is stored in biomass in the form of chemical energy. It has the characteristics of renewable, low pollution, wide distribution, and large total amount. , is a high-quality renewable energy source. When biomass, especially agricultural and forestry waste, is used as fuel, it has variety and complexity, high combustible volatile content, low sulfur content, low ash content, low bulk density, high alkali metal content, and low ash melting point. Features. Circulating fluidized bed boiler combustion technology has good fuel adaptability, so it has developed rapidly in the field of biomass combustion power generation in recen...

AI Technical Summary

Problems solved by technology

[0006] When the bed material is enriched with silica SiO 2 , silica SiO 2 Compatible with sodium carbonate Na 2 CO 3 or Potassium Carbonate K 2 CO 3 etc. react to form a low-temperature eutectic mixture, which will cause the problem of cohesion of the bed material, which will affect the fluidization quality of the bed material. In severe cases, it will cause large-area agglomeration and slagging of the bed, resulting in the shutdown of the boiler.

[0007] Although some biomass fuels such as rice husks have a high volatile content of combustible base, the fuel ignition temperature is low, and it is easy to catch fire. However, when the combustion temperature is higher than 900 ° C, the fuel ash is easy to form carbon-silicon complexes, which hinders combustion. progress, the fuel is hard to burn

Images