CN-121977213-A - Garbage disposal system based on fly ash backfire and low-nitrogen combustion

Abstract

The invention discloses a garbage disposal system based on fly ash backfire and low-nitrogen combustion, which comprises a garbage incineration waste heat boiler and a flue, wherein a flue gas recirculation nozzle is arranged at a front arch and/or a rear arch of a hearth, a tail section flue is connected with a recirculation pipeline, the recirculation pipeline is connected with the flue gas recirculation nozzle, an ash bucket is arranged at a position where a second flue is communicated with a third flue, an ash discharge port is arranged at the lower part of the ash bucket, and a water-cooling flow guide screen is arranged at the ash bucket and used for separating large-particle fly ash. The invention has the advantages that the two functions of reducing nitrogen oxides and improving combustion efficiency are combined into one, the generation of thermal NOx is restrained, the ignition of garbage entering the furnace is facilitated, the water-cooling guide screen can reduce particles, the combustion efficiency is further improved while the emission of nitrogen oxides is reduced, the combustion efficiency of the garbage furnace is effectively improved, and the fly ash is melted by utilizing the cyclone combustion technology, so that harmless treatment is realized.

Inventors

• Rong Yibang
• HU PINGYU
• XIAO WEIDONG
• LIU XIAOZHOU
• Zhan Denggao
• LI GUIFU
• WANG MINGJIN

Assignees

• 普宁市广业粤能环保能源有限公司
• 广东工业大学

Dates

Publication Date

20260505

Application Date

20251226

Claims (10)

1. 1. A garbage disposal system based on fly ash backfire and low-nitrogen combustion comprises a garbage incineration waste heat boiler, a first flue, a second flue, a third flue and a final flue, wherein a hearth of the garbage incineration waste heat boiler is connected with the first flue through a furnace mouth, the first flue is connected with the second flue, the second flue is connected with the third flue, and the third flue is connected with the final flue.
2. 2. The garbage disposal system based on fly ash back combustion and low nitrogen combustion according to claim 1, wherein the flue gas recirculation nozzles are arranged on the inner side wall of the hearth, the number of the flue gas recirculation nozzles is 6-10, the diameter of the flue gas recirculation nozzles is 50-80mm, the spraying speed of the flue gas recirculation nozzles is 50-80m/s, the direction of the spraying nozzles is inclined downwards, and the included angle between the spraying nozzles and the horizontal plane is 15-45 degrees.
3. 3. The garbage disposal system based on fly ash backfire and low nitrogen combustion according to claim 2, wherein an ash bucket is arranged at the communication position of the second flue and the third flue, an ash discharge port is arranged at the lower part of the ash bucket, and a water-cooling flow guide screen is arranged in the ash bucket and used for separating large-particle fly ash.
4. 4. A waste disposal system based on fly ash backfire and low nitrogen combustion according to claim 3, wherein said water-cooled guide screen is arranged in the ash bucket from top to bottom, the height is 1/3-1/2 of the height of the ash bucket, the thickness is 60-100mm, the arrangement is inclined forward, and the inclination angle is 15-30 °.
5. 5. The system of claim 4, wherein the upper end of the water-cooled deflector is fixed to the lower portion of the retaining wall between the second flue and the third flue.
6. 6. The garbage disposal system based on fly ash back combustion and low nitrogen combustion according to claim 5, wherein a mixing device is installed at the lower part of the ash discharge port, a recycling pipeline is provided with a branch recycling connected with an inlet of the mixing device, and an outlet of the mixing device is connected with the flue gas recycling nozzle.
7. 7. The system of claim 6, wherein the water-cooled baffle comprises a coiled pipe, a first panel and a second panel, the coiled pipe is coiled between the first panel and the second panel, a water inlet of the coiled pipe is connected with an external water inlet pipe, and a water outlet of the coiled pipe is connected with an external water outlet pipe. And a plurality of fins are arranged on the outer surfaces of the first panel and the second panel.
8. 8. The garbage disposal system based on fly ash back combustion and low nitrogen combustion according to claim 7, wherein the final flue is provided with a cyclone separator, a cyclone ash bucket of the cyclone separator is connected with a cyclone combustion cylinder, a flue gas discharge port of the cyclone combustion cylinder is connected with a second recirculation pipe, and the second recirculation pipe is connected with a flue gas recirculation interface at the rear part of the furnace.
9. 9. The garbage disposal system based on fly ash back combustion and low nitrogen combustion according to claim 8, wherein the cyclone combustion cylinder is provided with a slag discharge port, and a water pool is arranged at the lower part of the slag discharge port.
10. 10. The garbage disposal system based on fly ash back combustion and low nitrogen combustion according to claim 8, wherein the fuel inlet of the cyclone combustion cylinder is connected with the coal dust input pipe, and 10% of coal dust is mixed in the fly ash.

Description

Garbage disposal system based on fly ash backfire and low-nitrogen combustion Technical Field The invention relates to the technical field of environment-friendly combustion of garbage, in particular to a garbage treatment system based on fly ash backfire and low-nitrogen combustion. Background At present, the emission standard of the flue gas executed by the Chinese household garbage incineration power plant is GB 1885-2014 "household garbage incineration pollution control standard", and the emission concentration limit value of NO x is 250mg/m 3. With the rise of environmental protection consciousness, more severe local standards or European Union 2010/75/E standards are implemented in a plurality of economically developed areas, and corresponding concentration standards are implemented by the emission of the household garbage incineration flue gas NO x. In the newly issued standard in recent years, the daily average emission concentration limit value of NO x is below 120mg/Nm 3, the minimum limit value is below 80mg/Nm 3, and compared with the emission reduction required in GB18485-2014, the emission reduction required by the standard is more than 50%, and the emission requirement on NO x of household garbage incineration is increasingly strict. In this large environmental background, the flue gas recirculation flue gas technology is increasingly receiving attention. The delayed recycling is a low-nitrogen combustion technology, can realize deep NO x removal in the furnace, and is widely applied to coal-fired and gas-fired boilers. And the flue gas recirculation technology is popular with people due to the advantages of simple process flow, remarkable effect of reducing NO x source, low investment and operation cost and the like. In the process of garbage incineration, high temperature is a key factor for generating nitrogen oxides. Under the conventional combustion working condition, the temperature of the hearth is often up to 1000-1200 ℃, and at the moment, nitrogen (N 2) and oxygen (O 2) in the air react violently to generate a large amount of thermal NO x, so that the reduction of NO x emission is also a problem to be solved in the current garbage incineration process. In addition, with the acceleration of the urban process and the continuous increase of the garbage production, the garbage incineration power generation technology has become an important means for urban solid waste treatment due to the advantages of reduction, harmlessness and recycling. However, during the waste incineration process, the flue gas carries a lot of fly ash into the tail flue of the waste heat boiler. If the fly ash is not separated in time, the fly ash can be deposited in the incinerator, so that the thermal efficiency of the boiler is reduced, the abrasion and corrosion of a heating surface are further increased, the burden of a subsequent flue gas purification system is increased, and the long-term stable operation of the system is influenced. Therefore, how to effectively reduce the fly ash amount in front of the tail flue becomes one of the key problems for optimizing the performance of the waste incineration waste heat boiler. The water-cooling guide screen is additionally arranged in the two-flue ash bucket and the three-flue ash bucket of the waste incineration waste heat boiler, so that the distribution of the flue gas flow field is optimized, the sedimentation effect of fly ash is enhanced, the amount of the fly ash entering the tail flue is reduced, and the accumulated ash on the heating surface is reduced. The unburned substances are reduced, the corrosion of the heating surface is reduced, and the combustion efficiency is improved. Finally, how the fly ash discharged from the waste furnace is treated is also a very important problem. The waste incineration fly ash contains high-concentration heavy metals (such as mercury, lead, cadmium, chromium and the like), and the leaching toxicity of the heavy metals is far more than the class III limit value 1 of the underground water quality standard. If the water is directly buried or stacked without treatment, heavy metals can permeate into soil and underground water through rainwater, so that the surrounding water environment is polluted. At present, the fly ash treatment process mainly adopts the following steps that more than 80% of soluble heavy metals in the fly ash can be removed through water washing pretreatment, and the leaching concentration of the heavy metals is reduced by more than 90% by combining with a chelating agent stabilization technology. However, this method is expensive and a low cost treatment method is required. Disclosure of Invention In order to overcome the defects of the prior art, the invention provides a garbage disposal system based on fly ash backfire and low-nitrogen combustion. The technical scheme includes that the garbage treatment system based on fly ash backfire and low-nitrogen combustion comprises a garbage incineration was