Heat provided by the combustion of waste combustion part of the combustion; countercurrent logistics direction, long residence time, to ensure that the waste is converted into fuel to the maximum extent possible; due to the gas flow rate of the gas flow rate is correspondingly low, resulting in the production of gas entrained in the particulate matter is also relatively small, reducing the potential impact on air pollution. However, there are some technical difficulties, such as viscous fuels need to be pre-treated; so that they do not cake when burned. Due to the upward airflow in the reactor, the temperature is low and contains much tar and other components, which is easy to block the gasification part of the pipeline.
2, fluidized bed reactor (fluidized combustion bed reactor)
In the fluidized bed, the gas and fuel with the flow direction of contact; reactor gas flow rate is high enough to make the particles suspended, making the solid waste particles dispersed, better reaction performance, fast. This process requires that the waste particles themselves be combustible; the temperature should be controlled to avoid melting of the ash to prevent it from fusing and clumping. Adapted to high moisture content or fluctuations in waste fuels, and equipment size is smaller than the fixed bed, but the heat loss is large, the gas takes away a large amount of heat and more unreacted solid fuel powder.
3, rotary kiln
Rotary kiln is an indirectly heated high temperature decomposition reactor.
Its main equipment is a slightly inclined cylinder, in the process of its slow rotation so that the waste material moving through the distillation vessel to the discharge port. The distillation vessel is made of metal, while the combustion chamber is made of refractory material. A portion of the gases produced by the decomposition reaction is burned in the space between the outer wall of the distillation vessel and the inner wall of the combustion chamber, and this heat is used to heat the waste. This type of unit requires that the waste must be finely crushed, generally less than 5cm in size, to ensure that the reaction proceeds completely.
4, dual-tower recirculation pyrolysis reactor
Including solid waste pyrolysis tower and solid carbon combustion tower. Characteristics: pyrolysis and combustion reaction separately in two towers. The heat required for pyrolysis is supplied by combustion of solid char or fuel gas generated by pyrolysis in the combustion tower. The inert thermal media (sand) absorbs heat in the combustion furnace and is drummed into fluidized state by the fluidized gas, which is returned to the combustion furnace through the contact pipe and then heated back to the pyrolysis furnace.
By combustion mode is divided into: grate type, hearth type, boiling fluidized bed.
1, grate-type incinerator The waste will be placed on the grate for incineration of the furnace, there are two types of fixed grate and movable grate incinerator fixed grate: can only be manually operated, intermittent operation, poor labor conditions, low efficiency, dial material is not sufficient when the incineration is not complete. Only for incineration of a small amount of flammable waste. The actual application of the more active grate incinerator, that is, mechanical grate incinerator.
Active grate:
(1) side-by-side shaking type
A series of fan-shaped grate regular horizontal row in the furnace. Grate up and down movement, so that the material forward movement, the adaptability of solid waste, can be used to higher moisture content of the garbage and to the surface and decomposition of the combustion form of solid waste combustion.
(2) inverse dynamic
The grate length is fixed, the width can be adjusted according to the required area of the hearth, which can be formed by a number of lateral combination of the hearth. Fixed grate and movable grate staggered configuration, movable grate reverse movement, waste due to gravity and slide. Large waste incineration.
(3) step type
For the inclined bed, in which the fixed and movable grate longitudinal staggered configuration, there is a stage drop.
(4) Caterpillar type
The grate consists of tracks that are in continuous motion. Less frequently used.
(5) drum type
The grate is 5~7 cylindrical rollers, arranged in an inclined position, rotating in the opposite direction between neighboring drums, with an independent primary air conduit that reaches the waste layer from the bottom of the drums through the air delivery holes on the surface of the drums.
2, hearth-type incinerator
The use of hearth material, combustion on the surface of the material in the hearth, suitable for dealing with small particles or powdered solid waste and slurry waste, divided into two categories of fixed hearth and movable hearth.
(1) fixed hearth - multi-stage furnace, also known as multi-chamber furnace or mechanical furnace, is a multi-chamber incinerator with mechanical drive, can be a long-term continuous operation, the reliability of the incineration device is quite high, widely used in the sludge incineration process. Disadvantages: more mechanical equipment, need more repair and maintenance; need secondary combustion deodorization. Fixed bed.
(2) movable bed - rotary kiln incinerator
Movable bed: turntable, tunnel, rotary.
Rotary kiln incinerator: the most widely used movable hearth incinerator. It is a slightly tilted and lined with refractory bricks steel hollow cylinder, the kiln body is usually very long, through the overall rotation of the furnace body to achieve uniform mixing of solid waste and along the angle of inclination to the discharge end.
Based on the combustion gases and solid waste in the same direction or not, rotary kiln incinerator is divided into two kinds of downstream and counter-flow. The former is often used to deal with high volatile solid waste; the latter is often used to deal with high moisture solid waste.
Temperature distribution is roughly as follows: drying zone 200 ~ 400 ℃, combustion zone 700 ~ 900 ℃, high-temperature melting and sintering zone
1100 ~ 1300 ℃
3, fluidized bed incinerator
The use of the bottom of the furnace distribution plate blowing hot air will be the waste of the suspended gas in a boiling state for combustion. Generally often use the intermediate media that the carrier (sand) for fluidization, and then add the waste to the fluidized bed with high temperature sand contact, heat transfer for combustion.
The current industrial application of fluidized bed has bubble bed and circulating bed two types. The former is mostly used to treat municipal waste and sludge; the latter is mostly used to treat hazardous industrial waste.
The incineration temperature is mostly kept at 400~980℃.