Flameless combustion system for semi-coke refractory fuel

Abstract

The invention belongs to the field of semi-coke combustion, and particularly discloses a flameless combustion system for semi-coke refractory fuel. The system comprises a combustion chamber, a burner,a powder feeding device and a flue gas treatment device, wherein the combustion chamber is divided into an inner combustion chamber and an outer annular combustion chamber by a partition plate; the lower end of the inner combustion chamber is provided with the burner; the upper end of the partition plate is provided with a tangential flow guiding outlet; the outer wall of the outer annular combustion chamber is provided with a water cooling pipe and a flue gas outlet; a return hopper is arranged at the bottom end of the outer annular combustion chamber; the burner comprises a primary air spray pipe, a flame secondary air spray pipe, a flameless secondary air spray pipe and a material returning spray pipe which are coaxially arranged, and also comprises an ignition assembly extending intothe inner combustion chamber; the powder feeding device is connected with the primary air spray pipe and used for providing fuel for the primary air spray pipe; and the flue gas treatment device comprises a waste heat exchanger and a dust remover which are sequentially connected. According to the system, combustion process and flue gas utilization process are separated, so that high-temperature environment required by the flameless combustion of the inner combustion chamber is ensured; and flue gas heat is effectively utilized.

Description

technical field [0001] The invention belongs to the field of semi-coke combustion, and more specifically relates to a flameless combustion system for semi-coke-like flammable fuels. Background technique [0002] Semi-coke is a by-product of coal hydrogasification. It is a fuel with extremely low volatile content (generally <5%) and high fixed carbon content. Semi-coke has the characteristics of high ignition temperature, slow reaction rate, and long burnout time. It is difficult to realize high-efficiency utilization of this kind of fuel by existing combustion technology. Therefore, it is necessary to develop special technologies and devices suitable for this type of fuel to realize the large-scale application of semi-coke. [0003] For ultra-low volatile fuels, CN103982894B proposes a combustion device for gasified semi-coke-like flame-retardant fine particle fuel and a combustion method using the device, hoping to solve the problem of low combustion efficiency of semi-...

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Problems solved by technology

[0003] For ultra-low volatile fuels, CN103982894B proposes a combustion device for gasified semi-coke-like flame-retardant fine particle fuel and a combustion method using the device, hoping to solve the problem of low combustion efficiency of semi-coke in a circulating fluidized bed. The patent proposes that semi-coke particulate fuel enters the dense-phase zone of the furnace for combustion through raw material bins, pneumatic injectors, and return inclined pipes. However, during the combustion process, semi-coke particles are directly sent into the furnace without preheating, which will cause them to burn out. The rate is still low and easy to flame out

CN106556007A proposes a method for combusting coal gasification semi-coke particles using thick-thin thickness-depth separation and controllable vortex stable combustion technology. The patent proposes that the primary air carrying gasified semi-coke powder be separated from thick and thin to obtain dense phase and dilute phase semi-coke The powder is sent to the inner, middle and outer nozzles of the combustion chamber respectively, but due to the method of physical separation, the wear of the nozzle of the combustion chamber may be serious, and the economy is not strong

At the same time, although the above-mentioned combustion devices or methods can improve the utilization efficiency of fuel to a certain extent, they still do not get rid of the shackles of traditional combustion. There is a high-temperature combustion zone in the furnace, and the emission of nitrogen oxides will still be relatively high.

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