Domestic garbage-stale garbage collaborative incineration method

Abstract

The invention provides a household garbage-stale garbage collaborative incineration method. A draught fan, a water cooling wall, a nozzle, a fire grate, a primary air mother pipe, a secondary air mother pipe, a primary air branch pipe, a secondary air branch pipe, an air heater, a flow adjusting valve and the like are included. A numerical simulation result shows that under the same operation condition, compared with original operation, the mixing method has the advantages that the garbage bed surface moisture evaporation rate, volatile matter pyrolysis rate and fixed carbon combustion rate are reduced, a high-temperature area is shrunk, the flue gas temperature is reduced, and the high-temperature adherence phenomenon is relieved. And on the premise that the national standard requirement that the incineration temperature is higher than 1123 K is met, the heat value of the mixed garbage is higher than 6849 kJ / kg. The operation method has the advantages that (1) the problem of large storage amount of the stale garbage is effectively solved, and the pollution of the stale garbage to the environment and soil is reduced; and (2) the phenomenon of high-temperature wall surface corrosion caused by high calorific value of the household garbage is effectively relieved, the operation and maintenance cost of the incinerator is saved, and the equipment damage risk is reduced.

Description

Technical Field

[0001] The new patent of the present invention relates to the technical field of waste incineration, and in particular to a method for the coordinated incineration of domestic waste and stale waste. Background Art

[0002] At present, my country's garbage disposal methods include landfill, incineration and composting. Incineration has gradually become the main method of garbage disposal due to its advantages of significant volume reduction, volume reduction and high utilization of organic resources. Since landfill was the main method of garbage disposal in my country in the early days, long-term landfill has led to a huge amount of stale garbage in my country, and landfill can easily cause large-scale ecological and environmental problems. This makes the rational treatment of stale garbage an important aspect of concern at this stage.

[0003] Stale garbage is the product formed after long-term landfilling. Since garbage is easy to undergo anaerobic fermentation after landfill, a large amount of organic matter is consumed. The combustible gases such as CH4 produced by garbage fermentation are transported to the ground through the gas collecting pipe, which leads to a decrease in the combustible content in the garbage, while the difficult-to-degrade materials (plastic, glass, rubber, etc.) are preserved for a long time. Therefore, stale garbage has the characteristics of high ash content and low calorific value compared with domestic garbage. Incineration is a feasible solution to treat stale garbage, but the incineration method requires that the calorific value of garbage should be no less than 4187kJ / kg. When directly incinerating stale garbage, it is necessary to add auxiliary fuels and other methods to supplement energy, which will increase the cost of garbage incineration and reduce the operating efficiency of the system. Therefore, mixing a certain proportion of stale garbage with domestic garbage is an effective way to solve the problem of stale garbage. On the one hand, it solves the problem of high stale garbage content; on the other hand, it reduces the high-temperature coking problem caused by the high calorific value of domestic garbage. Since the calorific value of stale garbage is much lower than that of domestic garbage, increasing the mixing ratio of stale garbage will cause the furnace temperature to drop seriously, and even the monitored temperature in the incinerator will be lower than the national standard requirements, and the operating efficiency of the incinerator will decrease. Therefore, adopting a reasonable mixing ratio of stale garbage is the main way to effectively solve the problem of stale garbage. Summary of the invention

[0004] In order to effectively solve the problem of large amount of stale garbage and reduce the pollution of stale garbage to the environment, soil, etc., the present invention proposes a method for the coordinated incineration of domestic garbage and stale garbage without changing the structure of the incinerator. Under this operating condition, the mixed burning of stale garbage can not only make the incinerator temperature not lower than the national standard requirement of 1123K, but also effectively reduce the risk of high-temperature coking in the furnace and reduce the operation and maintenance cost of the garbage incinerator.

[0005] The invention proposes a method for the coordinated incineration of domestic waste and stale waste, comprising: a fan, primary and secondary air main pipes, primary and secondary branch pipes, an air heater, a flow regulating valve, a grate, a water-cooled wall, a nozzle and other components.

[0006] The method for the coordinated incineration of domestic waste and stale waste is to adjust the proportion of the stale waste to be incinerated during the operation of the incinerator.

[0007] Furthermore, the old waste was collected from different heights of the landfill, and the five-point sampling method was used to collect samples from each layer to ensure representativeness of the samples.

[0008] Furthermore, the calorific values ​​of the stale garbage are 2110, 3046, 4020 and 5156 kJ / kg respectively.

[0009] The domestic waste is high calorific value waste that has been dehydrated in the waste bin for 7 days.

[0010] Furthermore, the calorific value of domestic waste is 7315 kJ / kg, and the stale waste is mixed into the waste bin according to the designed mixing ratio.

[0011] The incinerator is operated under the following conditions: the total primary air volume and temperature are 45700 Nm 3 / h and 463K, the air volume ratio of each air chamber is 12:19:17:12:17:23; the total amount and temperature of secondary air are 8320Nm 3 / h and 303K, the secondary air directions of the front and rear arches are 20° and 0° respectively, and the numbers of the secondary air nozzles of the front and rear arches are 7 and 8 respectively.

[0012] The mixed burning simulation is carried out for the collected stale garbage. According to the CFD numerical simulation results, the present invention has the following beneficial effects:

[0013] For the rates of each stage of the waste incineration process, increasing the mixing ratio of stale waste will lead to slower evaporation of water, pyrolysis of volatiles and combustion of fixed carbon, and postpone the end of waste incineration; increasing the calorific value of stale waste will lead to faster evaporation of water, pyrolysis of volatiles and combustion of fixed carbon, and shorten the length of waste incineration.

[0014] As for the oxygen content at the incinerator outlet, increasing the mixing ratio of stale garbage will lead to an increase in the oxygen content at the incinerator outlet, and increasing the calorific value of stale garbage will lead to a decrease in the oxygen content at the incinerator outlet.

[0015] The incineration of stale garbage can reduce the flue gas temperature of the incinerator, shrink the high-temperature area, and control the problem of coking in the furnace. Under the premise of ensuring the incineration temperature is not lower than 1123K, the calorific value of the mixed garbage is not lower than 6849kJ / kg. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is a plan view of the incinerator used in the method for coordinated incineration of domestic waste and stale waste described in the present invention.

[0018] Figure 2 This is a plan view of the secondary air of the incinerator used in the method for coordinated incineration of domestic waste and stale waste described in the present invention.

[0019] Figure 3 The invention discloses a method for sampling stale garbage used in the method for co-incineration of domestic garbage and stale garbage described in the present invention.

[0020] List of reference numerals: drying section grate 1, combustion section grate 2, burnout section grate 3, fan 4, air heater 5, primary air main pipe 6, rear arch secondary air main pipe 7, front arch secondary air main pipe 8, primary air branch pipe 9, rear arch flow regulating valve 10, front arch flow regulating valve 11, water-cooled wall 12, secondary air branch pipe 13, nozzle 14. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0022] 1. Sampling process A detailed introduction to sample collection is given. First, the position of the diagonal center point is determined according to the shape of the landfill. Then, based on the center point, four points at the same distance (D / 2) from the center point are selected along the diagonal direction to determine the five sampling points on the first floor. Each sampling point collects 200 kg of stale garbage and mixes it thoroughly before piling it into a circle. The garbage is evenly divided into four equal parts by the quartering method. Two parts in the diagonal direction are randomly removed, and the remaining two parts are mixed again. The above steps are repeated until the garbage sampling volume reaches 15 kg and the operation is stopped.

[0023] 2. Incineration process The stale garbage is put into the garbage bin in proportion for mixing. The mixed garbage is pushed into the grate bed by the pusher. Under the action of the grate, it slowly passes through the drying section 1, combustion section 2 and burnout section 3 grates in sequence. The primary air is sent to the air heater 5 under the push of the fan 4. After preheating, it is sent to the primary air chamber under each section of the grate through the primary air branch pipe 9. The high-temperature primary air promotes the garbage to go through the drying, pyrolysis, combustion and burnout process, and finally removes the ash at the end of the burnout section 3 grate. Under the action of the fan 4, the secondary air is sent to the corresponding secondary air nozzle 14 through the front arch flow regulating valve 11 and the rear arch flow regulating valve 10 respectively. The volatile gas generated by the combustion is mixed with the high-speed secondary air of the front and rear arches for secondary combustion.

[0024] 3. Heat exchange process The waste incineration process in the furnace of the incinerator is approximately an adiabatic process. The high-temperature flue gas generated by the incineration moves upward along the flue, and during the movement, it undergoes radiation and convection heat exchange with the water-cooled wall 12 on the surface of the waste heat boiler. The temperature of the flue gas gradually decreases after the heat exchange. At the same time, the saturated water in the water-cooled wall vaporizes after absorbing heat. The high-temperature and high-pressure water vapor converts heat energy into electrical energy through the steam turbine. The water vapor after heat exchange is liquefied into saturated water to achieve the effect of recycling.

[0025] The above are only preferred implementations of this patent. It should be pointed out that various modifications and improvements can be made without departing from the principles of this patent, which should also be regarded as the scope of protection of this patent.

[0026] The embodiments of the present invention are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the invention.

Claims

1. A method for the coordinated incineration of domestic waste and stale waste, mainly comprising: Components including fans, primary and secondary air main pipes, primary and secondary air branch pipes, air heaters, flow regulating valves, grates, water-cooled walls and nozzles.

2. The operating condition of the method for co-incineration of domestic waste and stale waste according to claim 1 is that the total amount of primary air is 45700Nm 3 / h, the air temperature is 463K, the air volume ratio of each air chamber is 12:19:17:12:17:23, and the total secondary air volume is 8320Nm 3 / h, the wind temperature is 303K, the secondary air injection angles of the front and rear arches are 20° and 0°, and the numbers are 7 and 8 respectively.

3. According to claim 1, a method for the coordinated incineration of domestic waste and stale waste adopts a five-point sampling method to collect stale waste at different heights in the landfill, and the calorific values ​​are 2110, 3046, 4020 and 5156 kJ / kg respectively. The domestic waste used is high calorific value waste that has been dehydrated in the garbage bin for 7 days, and the calorific value is 7315 kJ / kg.

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