How to select and incinerate according to the municipal waste incineration equipment

Typical incinerator technical characteristics of the analysis

1.1 Mechanical grate incinerator

Mechanical grate incinerator combustion of the basic principles of roughly the same, according to the structure of the grate and the movement of the different ways and the form of a variety of ways can be divided into reciprocating grate furnace and multi-stage rolling grate furnace.

1.1.1 Reciprocating grate incinerator

Reciprocating grate incinerator is composed of a set of fixed grate pieces and a set of reciprocating movement of the activities of the grate pieces can be divided into downward push and reverse push type. The Japanese Tian Xiong SN reciprocating grate furnace used in Tianjin Shuanggang waste incineration power plant is set up with 2 steps and adopts sufficient grate area to make the garbage tumble and burn inside the furnace; 4 driving units are used: 1 in the drying stage, 2 in the combustion stage, and the other in the ignition stage. Therefore, the thickness of the garbage and ash layer can be controlled by adjusting the speed of each independent drive unit.

Qinhuangdao waste power plant feasibility study in the amount of waste for the size of 1000t / d, the choice of two-stage reciprocating grate (reverse push + downward push) waste incinerator, two-stage reciprocating waste incinerator is divided into the reverse push section and the downward push section of the two combustion areas, grabs the garbage from the garbage pool into the drop chute, in the feeder pushed into the furnace fall on the inclined reverse push grate, the garbage in the bed of the Rubbish in the bed constantly rolling, stirring, to complete the drying, fire and combustion process, and then in the reverse push the end of the grate after a period of fall into the smooth push grate bed to continue to burn, and finally the ash through the slag machine discharge out of the furnace. Reciprocating push grate material requirements are high, the processing precision is also very high, the contact surface between the grate and the grate is very smooth, it is difficult for small dust to leak out from between the gaps, for the small amount of ash leaking into the air chamber, there is another removal device to push it into the slag machine. The interactive movement between the grates can make the grate surface achieve the purpose of self-cleaning.

1.1.2 Multi-stage grate incinerator

Multi-stage grate incinerator grate is divided into five different units, each unit consists of two rows of sliding grate sheet, two rows of turning grate sheet and two rows of fixed grate sheet. The sliding grate forms a horizontal movement to ensure that the waste combustion layer moves forward horizontally, and the turning grate forms an up and down movement to ensure that the waste layer turns over and moves (see Figures 1 and 2)

Figure 1 Action of the turning grate: mixing and venting of the waste

Figure 2 Action of the sliding grate: gulping of the waste

The action of the turning grate is particularly advantageous for the incineration of low calorific value waste. This is particularly advantageous for the incineration of low calorific value waste. Because turning the grate sheet helps to loosen the material layer, so that the waste is better mixed, uniformly fed to ensure the complete incineration of fixed carbon particles and fermented waste, so that the ash slag contains a minimum of combustible particles, the thermal burn rate is less than 3%.

Mechanical grate incinerator can incinerate a wide range of calorific value fluctuations in a variety of garbage, grate material selection should be good, the structure of the use of elastic wear-resistant scraper, coupled with a good cooling effect of primary wind on the grate and the precision of the various moving parts of the coordination of the grate piece of durability is extremely high, can withstand high temperatures of 950 ℃.

1.2 Fluidized bed incinerator

Fluidized bed high-efficiency incinerator working principle is to add the garbage into the fluidized bed with high temperature sand contact, heat transfer combustion, the fluidized bed is the bottom of the furnace distribution plate blowing hot air will be blown out of the garbage and sand floating in the form of boiling and formed. The biggest difference between it and the mechanical grate incinerator is that there is no moving grate in the furnace, and the furnace body is usually arranged vertically. The process is: garbage into the hopper, with a screw conveyor to the incinerator upper feed port, and the furnace 600 ~ 700 ℃ high temperature sand contact, garbage is heated, dry, fire and combustion. After combustion ash due to gravity from both sides down into the bottom of the spiral conveyor, and use it to send ash to the vibrating screen connected to the non-combustible materials and sand particles separate, sand particles and then sent to the recycling elevator, re-introduced into the furnace, non-combustible materials discharged out of the furnace.

The main characteristics of the fluidized bed incinerator is the bed temperature uniformity, the garbage particles and fluid contact is good; fast reaction, complete incineration, high thermal intensity, its thermal efficiency can generally reach 80% to 82%, the garbage combustion rate is also very high, incineration of slag discharged after the unburned components can reach about 1%; equipment size is relatively small, the type of fuel requirements are more stringent. The disadvantage is that the garbage must be sorted and crushed, the sorting and crushing system is complex and consumes a lot of power, at the same time to make the garbage and the coal body in the fluidized state must also consume a lot of power, the fluidized solid particles of the furnace wall wear and tear is serious, due to the low calorific value of the domestic garbage, it is difficult to burn alone, and need to mix with the coal for burning [1].

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