SU926435A1 - Furnace for burning wooden powder - Google Patents

Description

The invention relates to the burning of wood waste, at the enterprises of the woodworking industry, and in particular to the burning of wood dust containing binders, which is obtained by grinding chipboard and fiberboard and cannot be used again for the manufacture of chipboard and fiberboard.

A device is known for burning waste in suspension by feeding it into a fluidized bed and supplying the air necessary for burning above the fluidized bed, as well as supplying secondary air to the furnace in a tangential direction (13 · The disadvantage of this device is the low thermal voltage of the volume of the combustion chamber, so how the afterburning of small particles and toxic gases is carried out over a fluidized bed in the gas space, which leads to large dimensions of the device.

The closest in technical essence and the achieved effect is; pulverized fuel burning furnace ^; containing a housing with a layer of inert disperse material, a distribution grid, distribution pipes for introducing secondary air G2].

A disadvantage of the known furnace is its low efficiency in burning wood dust containing binders, and an increased risk of increasing the load of the furnace.

The purpose of the invention is to increase the efficiency of the process when burning wood dust.

, _ The goal is achieved in that in the furnace ¹⁵ for burning wood dust containing a housing, a distribution grid, distribution pipes for introducing secondary air and a layer of inert disperse material, the distribution pipes are mounted vertically with the possibility of movement, the lower ends of the pipes are equipped with cordless caps and placed in a layer of inert disperse material.

The drawing shows a furnace for burning wood dust containing binders.

The furnace contains a housing 1, a distribution grid 2 with a collector for supplying primary air and wood dust to the furnace, a layer of inert material 4, for example river sand with a particle diameter of at least 1.5 mm, a collector 5, vertical pipes 6 for the supply of secondary air, the lower ends of which are equipped with wireless caps 7 and placed in the upper zone of the dispersed material 4, seals 8, gas duct 9 to remove “combustion products from the furnace. Pipes 6 10 are installed with the possibility of vertical movement.

The furnace for burning wood dust containing binders, operates as follows. fifteen

Previously, it burns fuel, such as natural gas or fuel oil, to heat an inert material above the auto-ignition temperature of wood dust. Then, the fuel supply is stopped 20, and through the distribution grid 2, using a collector 3, a mixture of wood dust containing binders and primary air with a coefficient of 25 air flow rate less than unity is supplied to the furnace at a speed that ensures fluidization of the inert dispersed material 4. Woody fluidization process Dust is ignited by particles of dispersed dispersed material, since their temperature is higher than the self-ignition temperature of wood dust. Due to the fact that the primary air flow rate is less than one, more dust can be supplied to the lower zone of the fluidization due to insufficient oxygen content without fear of explosion than during incineration with a flow coefficient of less than one, which increases the furnace productivity. For this reason, incomplete combustion of wood dust occurs in this zone, accompanied by intensive thermal decomposition of 45 binders and the release of toxic gases. The products of incomplete combustion rise to the upper fluidization zone, where for their complete combustion through vertical pipes an additional 50 is supplied but secondary air with a flow coefficient greater than unity is supplied. Since a significant part of the pipes 6 is located in the superlayer space, they are washed by the combustion products leaving the fluidized bed, which heat the secondary air. Heated secondary air through the capless caps 7 enters the upper fluidization zone, where, due to) the flow coefficient is greater than unity; wood dust and toxic gases are completely burned. The heat released during this process is perceived by particles of inert material due to their intensive mixing, is transferred to the lower fluidization zone, stabilizing and intensifying incomplete combustion processes.

Wireless caps 7 prevent breakthrough of secondary air into the lower fluidization zone, where the primary air flow rate should be less than unity, thereby contributing to a clear separation of the fluidized bed into two zones: lower and upper.

Moving the pipes 6 in the vertical direction, depending on the type of wood dust being burned, the ratio of the upper and lower fluidization zones is selected, which ensures the highest furnace productivity and complete combustion.

The combustion products are removed from the furnace through the gas duct 5 and sent for technological needs, for example for drying the crushed wood, intended for the manufacture of chipboards.

The proposed design of the furnace allows the burning of wood dust containing binders at elevated concentrations, which leads to increased productivity, provides safe and complete combustion of wood dust and toxic gases released during thermal decomposition of binders.

Claims (2)

3 for supplying primary air and wood dust to the furnace, a layer of inert material 4, for example river sand with a particle diameter of not less than 1.5 m, a collector 5, vertical pipes 6 for supplying secondary air, the lower ends of which are provided with besrunal caps 7 and placed in the upper zone of the particulate material 4, the seal 8, the flue 9 to remove the combustion products from the furnace. The pipes 6 are installed with the possibility of vertical movement. A furnace for the burning of dust dust containing burning substances is as follows. Fuel is preliminarily burned in it — for example, natural gas or fuel oil — to heat inert material above the auto-ignition temperature of wood dust. Then the supply of fuel is stopped, and through the distribution grid 2, using a collector 3, a mixture of wood dust containing substances and primary air with an air flow rate less than 1 is fed into the furnace with a speed that provides fluidization of the inert dispersed material 4. In the process of fluidization, wood The dust ignites from particles of the heated incisive material, since their temperature is higher than the self-ignition temperature of wood dust. Due to the fact that the flow rate of the primary air is less than one, more dust can be fed into the lower fluidization zone due to insufficient oxygen content, without fear of an explosion, than when burned with a consumption ratio less than unit, which leads to an increase in furnace productivity. In this zone, for the reason indicated, incomplete combustion of wood dust occurs, accompanied by intense thermal decomposition into burning substances and the release of toxic gases. The products of incomplete combustion are lifted into the upper fluidization zone, where additional air is supplied through the vertical pipes with a flow coefficient greater than one to ensure their complete combustion. Since a significant part of the pipes 6 are located in the super layer space, they are washed by the combustion products leaving the fluidized bed that heat the secondary air. The heated secondary air enters the rear fluidized zone through the non-fluidized beds, where due to the fact that its coefficient of discharge is greater than one, the complete combustion of wood dust and toxic gases occurs. The heat released during this process is perceived by particles of inert material due to their intensive mixing, transferred to the lower zone of the fluidization, stabilizing and intensifying the processes of incomplete combustion. Relief caps 7 prevent the breakthrough of secondary air into the lower fluidization zone, where the primary air flow rate must be less than one, thus contributing to a clear separation of the fluidized bed into two zones: the lower and upper. Moving the pipes 6 in the vertical direction, depending on the type of wood dust being burned, select the ratio of the upper and lower fluidization zones, which provides the highest furnace productivity and full combustion. Combustion products are removed from the furnace through the duct 5 and sent for technological needs, for example for drying shredded wood intended for the manufacture of particleboard. The proposed design of the furnace makes it possible to burn wood dust containing tangent substances at elevated concentrations, which leads to a decrease in productivity, ensures safe and complete combustion of wood dust and toxic gases released during thermal decomposition in the burning substances. Claims for burning wood dust, comprising a housing with a layer of inert particulate material, a distribution grid, distribution pipes for introducing secondary air, characterized in that, in order to improve the efficiency of the process of burning wood dust containing substances distribution pipes are mounted vertically with the possibility of movement, with the lower ends of the pipes equipped with pressureless caps and placed in a layer of inert dispersed material. Sources of information taken into account in the examination 1. US patent 4075953, cl. 110-8 F, 1978 .. 2. Zabrodsky S.S. Fluidized bed fluid temperature installations. M., Energie, 1971, p. 145-149 (prototype). .