CN114963185A - Method for filtering pollutants by coupling medical waste high-temperature pyrolysis gasification and low-nitrogen combustion with dry type electric filter - Google Patents

Abstract

The invention discloses a method for filtering pollutants by medical waste through high-temperature pyrolysis gasification-low-nitrogen combustion coupling dry-type electric filtration, which comprises the steps of feeding the medical waste into a pyrolysis incinerator through a feeding machine, cracking organic matters in the medical waste into combustible mixed gas at 850-1600 ℃ without oxygen or oxygen deficiency, enabling the cracked gas to enter a secondary combustion chamber for combustion under the condition of oxygen enrichment, enabling high-temperature flue gas after combustion to enter a partition wall heating chamber of the pyrolysis incinerator through a pipeline, connecting a heat exchanger with the partition wall heating chamber of the pyrolysis incinerator, enabling high-temperature tail gas to exchange heat with blown oxygen in the heat exchanger, and enabling the heated oxygen to enter the secondary combustion chamber; the tail gas discharged from the heat exchanger enters a Venturi mixer, is mixed with alkaline nano particles, then enters a dry reactor and an electric filter reactor, and the purified gas is led to a chimney by a draught fan and is discharged into the atmosphere; the removal rate of organic matters reaches 99%, and the generation of harmful substances such as dioxin is reduced; realizing the harmless treatment of the garbage.

Description

High temperature pyrolysis gasification of medical waste-low nitrogen combustion coupled with dry electrofiltration method for pollutants

technical field

The invention relates to the technical field of medical waste treatment, in particular to a method for high-temperature pyrolysis gasification-low-nitrogen combustion coupled with dry electric filtration of medical waste to remove pollutants.

Background technique

Medical waste refers to wastes with direct or indirect infectious, toxic and other hazards generated by medical institutions in medical treatment, prevention, health care and other related activities, including infectious, pathological, damaging, pharmaceutical, chemical Waste, which contains a large amount of bacterial viruses, will cause serious pollution to the environment if not handled properly, and may also become the source of epidemics. After nearly 20 years of development, the incineration treatment technology with rotary kiln and fixed bed as the core and the non-incineration treatment technology of medical waste with high temperature steam, chemical, microwave and high temperature dry heat as the core have been widely used. The treatment of medical waste at home and abroad basically adopts incineration treatment. Although the incineration method can realize the harmless, reduction and resource treatment of garbage at the fastest speed, and has the advantage of occupying less land resources, the incineration process produces waste. The waste gas and residues have a particularly large impact on the environment, and will also produce serious dioxin problems, causing serious secondary pollution to the environment. Additional production lines need to be invested to purify gas pollutants, so it is necessary to carry out technical Innovate to solve specific problems.

SUMMARY OF THE INVENTION

In order to overcome the defects in the prior art that the pollution of medical waste to the environment is becoming more and more serious, and it is impossible to treat the medical waste in a harmless, quantitative and resourceful manner, the present invention provides a medical waste treatment method. By optimizing the pyrolysis incineration The structure and parameters of the furnace achieve a high cracking rate, and the entire furnace body is strictly sealed to achieve anaerobic cracking and maximize gas production. Due to the high pyrolysis temperature, the incineration process is complete, the volume reduction of solid particles is high, and the organic matter removal rate reaches 99% Therefore, the cost effect of the follow-up treatment is greatly reduced, and the high-temperature flue gas of the second combustion chamber is sent to the pyrolysis incinerator as a heat source to maintain the temperature of the furnace body, which reduces the use of fuel and reduces the cost; After the waste heat is recovered, it is treated by dry reaction and electric filtration technology to meet the standards and discharge, which will not cause secondary pollution to the environment.

The method of the invention is to feed the medical waste into a pyrolysis incinerator through a feeding machine, and crack the organic matter in the medical waste into a combustible mixed gas at 850-1600° C. in anoxic or anoxic condition, wherein the pyrolysis incinerator comprises: The pyrolysis chamber and the partition heating chamber surrounding the pyrolysis chamber; the pyrolyzed gas enters the secondary combustion chamber for combustion under oxygen-rich conditions, and the high-temperature flue gas after combustion enters the partition heating chamber of the pyrolysis incinerator through the pipeline, and the heat exchanger It is connected to the high-temperature exhaust gas outlet of the partition heating chamber of the pyrolysis incinerator. The high-temperature exhaust gas exchanges heat with the oxygen blown in by the air compressor in the heat exchanger, and the heated oxygen is passed into the secondary combustion chamber; The exhaust gas enters the Venturi mixer, mixes with the alkaline nanoparticles, and then enters the dry reactor to remove the sulfide in the exhaust gas and preliminarily dedust, and finally the exhaust gas enters the electric filtration reactor to remove the fine dust retained in the exhaust gas. and pollutants, the purified gas is led to the chimney by the induced draft fan and discharged into the atmosphere.

An electromagnetic heating coil is arranged on the outer wall of the lower part of the pyrolysis chamber of the pyrolysis incinerator, which is used to provide the energy required for pyrolysis to start. After the high temperature reaction is started, the circulating flue gas passing into the heating chamber of the partition wall can continuously provide the pyrolysis process. Heat; the upper part of the pyrolysis chamber is provided with a pyrolysis chamber flue gas outlet and is connected to the secondary combustion chamber flue gas inlet of the secondary combustion chamber, an arc lighter is arranged at the secondary combustion chamber flue gas inlet of the secondary combustion chamber, and the bottom of the secondary combustion chamber is provided with an arc lighter. A fuel gas compensation port is provided to supplement the fuel gas when the flue gas production is reduced to ensure that the flue gas combustion has sufficient temperature. The lower part of the secondary combustion chamber is provided with an oxygen inlet, and the intake of the oxygen inlet is tangential intake. The upper part is provided with the high temperature flue gas outlet of the secondary combustion chamber.

The garbage in the pyrolysis incinerator moves from top to bottom by gravity, and forms a drying layer, a pyrolysis layer, and a slag layer from top to bottom in the furnace. Slag; pyrolysis gasification decomposes into combustibles such as carbon monoxide and gaseous hydrocarbons and forms combustible mixed flue gas, and then the garbage entering the pyrolysis incinerator is dried by the flue gas rising by pyrolysis in the upper part of the pyrolysis incinerator, and the moisture in it Volatile, as the temperature continues to rise, the garbage forms ash in the bottom layer of the furnace, and the cracking rate of the organic components in the medical waste reaches more than 99%, and the reduction effect is good; The water vapor and CO ₂ generated in the cracking process react with the hot carbon layer to form water gas, which makes the gas production in the whole process large.

The combustible mixed gas produced by waste pyrolysis enters the secondary combustion chamber through the flue gas inlet of the secondary combustion chamber, and the combustion temperature is controlled to not be lower than 1100 °C, which reduces the generation of dioxins, and the tangential and uniform air intake of the oxygen inlet can make The flue gas generates strong turbulent flow in the secondary combustion chamber and has sufficient residence time. The high-temperature flue gas is introduced into the heating chamber of the partition wall of the pyrolysis incinerator through the high-temperature flue gas outlet of the secondary combustion chamber. On the one hand, it provides thermal energy for the pyrolysis furnace to achieve the recycling of additional calorific value, and on the other hand, the unburned combustible gas is re-burned. Complete gas, further reducing pollutant generation.

The dry reactor is a conventional commercially available reactor, which is used for removing sulfide in the tail gas and preliminary dedusting.

The electrofiltration reactor is used to remove the fine dust retained in the tail gas and various pollutants in the flue gas, so as to meet the prescribed flue gas emission standards and reduce environmental pollution; this reactor is a technology disclosed by the inventor. Patents CN201410368552.8, CN202010853319.4, CN201810351642.4, CN201910212368.7, etc.

The electromagnetic heating device arranged on the outer wall of the pyrolysis furnace is used to supply energy needed for pyrolysis startup. After the high temperature reaction is started, the circulating flue gas introduced into the heating chamber of the partition wall can continuously provide heat for the pyrolysis section. In the whole process, the pyrolysis chamber does not need to add additional combustion-supporting substances, and the waste can be dried, heated and pyrolyzed in the furnace to realize the high-temperature pyrolysis and maintain the reaction temperature at 850-1600°C. The pyrolysis furnace can crack macromolecular substances into combustible low molecular substances such as hydrogen, methane, carbon monoxide, and liquid products such as tar, solvent oil, etc. The more harmful Cr ²⁺ and NO _x gases are generated, and the content of harmful components in the gas is reduced.

Alkaline nanoparticles include sodium bicarbonate, lime powder, calcium hydroxide, etc., and the neutralization reaction occurs when the acidic substances in the flue gas pass through this area.

The beneficial effects of the present invention are:

1. The present invention treats medical waste through high-temperature pyrolysis, converts organic matter in the waste into combustible mixed gas, and realizes the complete cracking of medical waste, with high conversion rate of combustible gas, high reduction degree, secondary The characteristics of low pollution;

2. The high-temperature pyrolysis treatment method is used in the present invention. In an oxygen-free or oxygen-deficient environment, the pyrolysis and gasification of medical waste produces extremely low dioxin content in the flue gas, which greatly reduces the generation of harmful gases and achieves Harmless of flue gas;

3. Use high-temperature pyrolysis technology to treat medical waste, recycle high-temperature flue gas to heat the furnace body, provide heat for the pyrolysis of medical waste, improve the heat utilization efficiency of the pyrolysis furnace, and reduce energy consumption;

4. The auxiliary desulfurization tail gas purification and dry reaction and electric filtration treatment facilities of the present invention can make the medical waste incineration treatment process without secondary pollutants;

The technical scheme of the invention is easy to realize, convenient to couple with the intelligent control system, low initial investment, and beneficial to market promotion.

Description of drawings

Fig. 1 is a schematic diagram of a process route of the present invention;

In the figure: 1-feeder; 2-pyrolysis incinerator; 3-second combustion chamber; 4-heat exchanger; 5-venturi mixer; 6-dry reactor; 7-electrofiltration reactor; 8 -Induced draft fan; 9-chimney; 10-air compressor; 11-oxygen inlet; 12-fuel compensation port; 13-second combustion chamber flue gas inlet; 14-arc lighter; 15-secondary combustion chamber high temperature flue gas outlet ; 16- partition heating chamber; 17- electromagnetic heating coil; 18- pyrolysis chamber; 19- pyrolysis chamber flue gas outlet; 20- partition heating chamber high temperature exhaust gas outlet.

Detailed ways

The process method of the present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments. As shown in Figure 1, the devices used in the following embodiments include a feeder 1, a pyrolysis incinerator 2, a secondary combustion chamber 3, a heat exchange 4, Venturi mixer 5, dry reactor 6, electrofiltration reactor 7, the feeder 1 is communicated with the feed port at the top of the pyrolysis incinerator 2, and the pyrolysis incinerator 2 includes a pyrolysis chamber 18 and a surrounding In the partition heating chamber 16 outside the pyrolysis furnace, the upper part of the pyrolysis incinerator is provided with a pyrolysis chamber flue gas outlet 19 and it communicates with the pyrolysis chamber 18, and the upper part of the pyrolysis incinerator is opened with a partition wall heating chamber high temperature exhaust gas outlet 20 which is connected to the upper part of the pyrolysis incinerator. The partition wall heating chamber 16 is connected, the bottom of the pyrolysis incinerator 2 is provided with an ash outlet and communicated with the pyrolysis chamber, the outer wall of the lower part of the pyrolysis chamber 18 is wound with an electromagnetic heating coil 17 connected to the power supply, and the pyrolysis chamber flue gas outlet 19 passes through The pipeline is communicated with the second combustion chamber flue gas inlet 13 of the second combustion chamber 3, the high temperature exhaust gas outlet 20 of the partition heating chamber is connected with the exhaust gas inlet of the heat exchanger 4 through the pipeline, and the exhaust gas outlet of the heat exchanger 4 is mixed with the dry type through the Venturi mixing 5. The reactor 6 is connected, the oxygen inlet of the heat exchanger 4 is connected with the air compressor 10, the oxygen outlet of the heat exchanger 4 is connected with the oxygen inlet 11 of the secondary combustion chamber, the intake of the oxygen inlet 11 is tangential intake, and the secondary combustion An arc lighter 14 is arranged on the side of the second combustion chamber flue gas inlet 13 of the chamber and is located in the second combustion chamber, the lower part of the second combustion chamber is provided with a fuel compensation port 12, and the upper part of the second combustion chamber is opened with a second combustion chamber high temperature flue gas outlet 15, The high temperature flue gas outlet 15 of the secondary combustion chamber is communicated with the partition heating chamber 16 through a pipeline, and the electrofiltration reactor 7 communicates with the chimney 9 through the induced draft fan 8;

Example 1:

In this embodiment, the above-mentioned device is used to process medical waste, and the medical waste is evenly and quantitatively fed into the pyrolysis incinerator 2 through the screw feeder 1, and the waste entering the pyrolysis incinerator 2 moves from top to bottom by gravity , turn on the electromagnetic heating coil 17 to provide the required heat for the pyrolysis start, the garbage in the pyrolysis chamber 18 is in an anaerobic environment or anoxic condition, and the control temperature is not lower than 1100 ℃. The organic matter is cracked to form combustible mixed flue gas, the combustible mixed gas is discharged through the flue gas outlet 19 of the pyrolysis chamber, and enters the secondary combustion chamber 3 from the secondary combustion chamber flue gas inlet 13 for combustion, and the control temperature is not lower than 1100 ° C, combustion The latter high temperature flue gas is transported to the partition heating chamber 16 through the high temperature flue gas outlet 15 of the secondary combustion chamber to provide heat for the pyrolysis process, and the recycled high temperature exhaust gas is discharged from the high temperature exhaust gas outlet 20 of the partition heating chamber and enters the heat exchanger 4 for waste heat. Recovery, after the high temperature exhaust gas and the oxygen heat exchange, the heated oxygen is passed into the second combustion chamber 3 by the oxygen inlet 11, and the exhaust gas enters the venturi mixer 5 after the heat exchange and adds sodium bicarbonate, and then enters the dry reactor 6, The acidic substances in the flue gas undergo a neutralization reaction with sodium bicarbonate and after preliminary dust removal, they enter the electrofiltration reactor 7 to remove the fine dust retained in the exhaust gas and various pollutants in the flue gas; after purification, the induced draft fan 8 leads it to The chimney 9 is discharged into the atmosphere;

In this embodiment, the medical waste is dried, heated, and gasified from top to bottom in the pyrolysis incinerator 2, and the waste passes through the drying layer, the pyrolysis layer, and the slag layer in sequence in the pyrolysis incinerator, that is, The incoming garbage is dried by the flue gas rising from the pyrolysis layer, volatilizes the moisture in it, then pyrolyzed and gasified, decomposed into combustibles such as carbon monoxide and gaseous hydrocarbons, and forms combustible mixed flue gas. Ash and slag are formed in the bottom layer of the furnace; at the same time, the water vapor, CO ₂ generated by the air entrained in the waste feed and its own humidity during the cracking process react with the hot carbon layer to generate water gas, which makes the gas production in the whole process large.

In this embodiment, the oxygen inlet 11 of the secondary combustion chamber 3 supplies oxygen evenly and tangentially, so that the flue gas can generate strong turbulent flow in the secondary combustion chamber 3 and have sufficient residence time to effectively remove dioxins; fuel The compensation port 12 supplements fuel gas when the flue gas production decreases to ensure that the flue gas combustion has a sufficient temperature.

After the above process treatment, the volume of the generated waste residue is 5% of the total volume of the medical waste before the reaction, and the volume reduction rate of the medical waste reaches 95%.

The high-temperature pyrolysis incinerator is composed of a pyrolysis chamber in the middle and a partition heating chamber surrounding the outside. The induced draft fan is arranged in the last section of the equipment, and the various systems are connected by pipes. After passing through each unit; the inner chamber is heated and cracked by electromagnetic heating and combustible mixed gas combustion self-heating (the heating temperature is between 850-1600 ° C), and the garbage is cracked during the heating process to generate combustible mixed gas, which is combustible. The combustible gas is introduced into the secondary combustion chamber for high temperature combustion (the combustion temperature is not lower than 1100°C); the secondary combustion chamber is equipped with an air guide system for even oxygen supplementation and sufficient volume to make the combustible gas swirl in the secondary combustion chamber. Increase the residence time of flue gas, and the residence time is greater than 2 seconds; add alkaline nanoparticles to the exhaust gas purification section by the Venturi mixer, the components are mixed into the reactor and react with the acidic components in the flue gas, and the acid gas is removed at a higher temperature, The exhaust gas does not need to be further cooled, and the multi-pollutant purification by electric filtration ensures that it will not cause secondary pollution to the environment.

The main components of medical waste are organic substances. The thermal pyrolysis of medical waste produces combustible gas for self-heating, which not only realizes the harmless treatment of medical waste, but also greatly improves the pyrolysis rate due to the optimized design of pyrolysis and incineration. The water vapor and CO ₂ generated by the air entrained in the material and its own humidity during the pyrolysis process react with the hot carbon layer to generate water gas, which maximizes the gas production of the pyrolysis and gasification of medical waste. The tail gas produced by the incineration of medical waste is discharged up to the standard after desulfurization, dust removal and electrofiltration.

Although the specific embodiments of the present invention are described above, those skilled in the art should understand that this is only an illustration, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims (4)

1. a method for high-temperature pyrolysis gasification of medical waste-low nitrogen combustion coupled with dry electrofiltration to remove pollutants, it is characterized in that: medical waste is fed into the pyrolysis incinerator by a feeder, and in anaerobic or deficient Oxygen, 850-1600 ℃, the organic matter in the medical waste is cracked into combustible mixed gas, and the pyrolysis incinerator includes a pyrolysis chamber and a partition heating chamber surrounding the pyrolysis chamber; the cracked gas enters the secondary combustion chamber and is rich in gas. Combustion under oxygen conditions, the high temperature flue gas after combustion enters into the partition wall heating chamber of the pyrolysis incinerator through the pipeline, and the heat exchanger is connected to the high temperature exhaust gas outlet of the partition wall heating chamber of the pyrolysis incinerator, and the high temperature exhaust gas is in the heat exchanger. The oxygen blown in by the compressor conducts heat exchange, and the heated oxygen is passed into the secondary combustion chamber; the exhaust gas discharged from the heat exchanger enters the Venturi mixer, mixes with the alkaline nanoparticles, and then enters the dry reactor for dehydration. In addition to the sulfide in the tail gas and preliminary dust removal, the tail gas finally enters the electrofiltration reactor to remove the fine dust and pollutants retained in the tail gas. The purified gas is led to the chimney by the induced draft fan and discharged into the atmosphere. 2. The method for high-temperature pyrolysis gasification of medical waste-low-nitrogen combustion coupled with dry electric filtration to remove multiple pollutants according to claim 1, characterized in that: the outer wall of the lower part of the pyrolysis chamber of the pyrolysis incinerator is provided with electromagnetic A heating device, the upper part of the pyrolysis chamber is provided with a pyrolysis chamber flue gas outlet and communicated with the secondary combustion chamber flue gas inlet of the secondary combustion chamber, an arc lighter is arranged at the secondary combustion chamber smoke inlet of the secondary combustion chamber, and the secondary combustion chamber The bottom is provided with a fuel compensation port, which is used to supplement fuel when the flue gas production decreases to ensure that the flue gas combustion has a sufficient temperature. The lower part of the secondary combustion chamber is provided with an oxygen inlet, and the intake of the oxygen inlet is tangential intake. The upper part is provided with the high temperature flue gas outlet of the secondary combustion chamber. 3. The method for high-temperature pyrolysis gasification of medical waste-low nitrogen combustion coupled with dry electrofiltration to remove multiple pollutants according to claim 1, wherein the alkaline nanoparticles comprise sodium bicarbonate, lime powder, hydroxide calcium. 4. The method for high temperature pyrolysis gasification of medical waste-low nitrogen combustion coupled with dry electrofiltration to remove multiple pollutants according to claim 1, wherein the combustion temperature in the secondary combustion chamber is not lower than 1100°C.

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