Compound biomass clean and efficient combustion system

Abstract

The invention relates to a compound biomass clean and efficient combustion system which comprises a hearth and a grate arranged at the bottom of the hearth. A boiler arch is arranged in the hearth and comprises a front arch body, a rear arch body and a flame folding arch body, all of which are arranged in a staggered manner to form a zigzag-shaped flue. The system further comprises a flue gas recirculation unit, a secondary air unit and an SNCR unit. The flue gas recirculation unit comprises a flue gas recirculation air pipe which is arranged at the position, above a middle section of the grate, on the side wall of the lower portion of the hearth. The secondary air unit comprises secondary air pipes which are arranged on the side wall of the hearth in a classified manner according to different height positions. The SNCR unit comprises an SNCR spraying opening formed in the side wall of the upper portion of the hearth, and the flue gas recirculation air pipe, the secondary air pipes and the SNCR spraying opening penetrate the side wall of the hearth and stretch in the hearth. Compared with the prior art, the problems that a biomass layer combustion boiler is high in air excess coefficient, incomplete in combustion, low in combustion efficiency, high in NOx emission concentration and the like are solved effectively.

Description

technical field [0001] The invention relates to a biomass combustion system, in particular to a composite biomass clean and efficient combustion system. Background technique [0002] With the consumption of fossil energy, the adjustment of energy structure and the needs of environmental governance in China, biomass energy has developed rapidly due to its renewability, low pollution and the need for proper disposal of agricultural and forestry waste itself. The most common form and the most widely used range, there are a variety of biomass energy utilization furnace types, structures and auxiliary equipment. [0003] The layer-fired boiler is the most widely used and produced boiler product in China. It is gradually applied to the combustion of biomass on the basis of relatively mature coal-fired design methods, but its current level limits the use of biomass energy. Extensive and effective use is mainly manifested in: the market and regulations put forward higher requiremen...

AI Technical Summary

Problems solved by technology

[0003] The layer-fired boiler is the most widely used and produced boiler product in China. It is gradually applied to the combustion of biomass on the basis of relatively mature coal-fired design methods, but its current level limits the use of biomass energy. Extensive and effective use, mainly manifested in: the market and regulations put forward higher requirements for various indicators of boilers, but the existing design force lacks sufficient understanding and response to the combustion and emission characteristics of biomass fuels

The volatile content of biomass fuel is high, most of which exceed 70%. The proportion of combustible gas in the furnace is high, and the requirements for mixing conditions in the furnace are high. Most of the biomass combustion rate is higher than that of coal. New design methods are required for the furnace structure and grate ; The backward grate manufacturing level has caused the high air excess coefficient required for grate burnout, and the widely used open furnace needs a large amount of secondary air to achieve gas burnout. The high air excess coefficient in the combustion process has caused Increased production of nitrogen oxides (NOx)

The standardization of the design of biomass bed-fired boilers has not been completed. The existing design methods have poor adaptability to biomass fuels and are difficult to meet the requirements of society and regulations. The adaptability is also poor. Most of the layer-fired biomass boilers in use have problems such as high air excess coefficient, incomplete combustion, low combustion efficiency, and high NOx emission concentration.

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