CN209309994U - Chlorine Waste High Temperature Plasma Recycling System - Google Patents

Abstract

The utility model belongs to industrial waste processing technology field, and in particular to a kind of high-temperature plasma resource utilization system of waste containing chlorine.The recovery system includes the feed system being sequentially connected, plasma gasification furnace, level-one afterheat heat exchanger, sour absorption system, caustic wash tower, dual firing chamber, second level afterheat heat exchanger, quencher, bag filter, flue heater, SCR catalytic tower, heat exchanger, air-introduced machine and chimney.The utility model realizes recycling, innoxious, minimizing and the stabilized processing of the high waste containing chlorine；Operating cost is low, and market application prospect is wide.

Description

Chlorine Waste High Temperature Plasma Recycling System

technical field

The utility model belongs to the technical field of industrial waste treatment, in particular to a high-temperature plasma recycling system for chlorine-containing waste.

Background technique

Existing chemical, pharmaceutical, pesticide and other industrial industries produce a large amount of highly chlorine-containing waste, the main organic components are chlorinated alkanes, chlorinated olefins, chlorinated benzene series, etc. These organic wastes are hazardous wastes, and if no treatment measures are taken, they will be directly Landfill or discharge will cause serious damage to the atmosphere, soil and water resources, threatening the environment on which human beings depend. Now basically adopt solidification method, landfill method or incineration method to deal with. The main processing methods are as follows:

1. Solidification method: stabilization/solidification technology, that is, hazardous waste is fixed or encapsulated in an inert solid substrate by inorganic pozzolanic materials or chemical stabilizers, and transformed into a highly insoluble stable substance, reducing the toxicity and Mobility, at the same time, improves the engineering properties of the treated objects for ease of transport and disposal. Solidification disposal technology is relatively mature, and the materials required are relatively cheap and sufficient, and can dispose of a wide range of hazardous wastes. Compared with incineration and composting, its disposal cost is lower. Of course, this technology also has some shortcomings, such as the volume and weight of the waste after disposal are increased, the solidification of waste containing organic matter is difficult, the disposal process requires skilled technical workers and expensive equipment, and improper operation during disposal It will cause secondary pollution and so on.

2. Landfill method: Landfill method is a land disposal method for hazardous waste, which consists of waste pretreatment facilities, waste landfill facilities and leachate collection and treatment facilities, which can isolate hazardous waste and leachate from the environment, The waste is safely stored for a considerable period of time (tens or even hundreds of years). However, the landfill method also has some disadvantages: the landfill site must be far away from residential areas; the landfill site has high requirements for anti-seepage treatment, and if it is not disposed of properly, it may easily cause groundwater pollution; Inflammable, explosive or toxic gases need to be controlled and treated. In addition, landfill is not the final means of disposal, it needs to occupy a large amount of land, and the later maintenance costs and risks are relatively high.

3. Incineration method: refers to the process of burning and incinerating waste to make it harmless. At present, the incineration mainly adopts rotary kiln, grate furnace and circulating fluidized bed and other processes. The incineration temperature is between 850-950 ℃, and the processing temperature is low, which is easy to produce highly toxic dioxins, furans and other substances; all are peroxygen combustion , a large amount of NOx is generated, and the load of the flue gas denitrification system in the later stage is large; waste incineration is not complete, and a large amount of slag is generated; when solid waste is processed, the exhaust gas contains a large amount of fine dust; according to the regulations in the hazardous waste catalog, hazardous waste incineration, pyrolysis and other disposal processes The generated slag and fly ash are still hazardous wastes, so the incineration process only reduces the amount of treatment, and does not achieve harmless and resourceful disposal.

To sum up, direct landfill or solidification of chlorine-containing waste cannot achieve reduction and recycling, and improper operation will pollute the environment; compared with landfill and solidification, incineration has higher treatment costs and produces The slag and fly ash are hazardous wastes and cannot be reused; and after incineration of chlorine-containing wastes, a large amount of acid gas HCl will be produced, which will increase the cost of flue gas deacidification in the later stage. If not handled properly, it will cause corrosion of equipment.

The current deacidification methods mainly include the following three types: dry deacidification, semi-dry deacidification and wet deacidification.

1) Dry deacidification is to spray slaked lime into the reactor through a special nozzle, let the surface of slaked lime particles directly contact with the acid gas in the flue gas, produce a chemical neutralization reaction, generate harmless neutral salt particles, and then enter the downstream Particulate removal equipment. The dry purification process is simple, easy to operate, and does not produce waste liquid, but the consumption of chemicals is large and the removal efficiency of HC1 is low.

2) The wet purification process generally uses a sodium hydroxide solution wet scrubber to deacidify. The wet purification process has a high removal efficiency of HC1, generally around 95%, but it requires large investment, large power consumption, large floor area, complex equipment, high concentration of inorganic chloride salts, and increased load on the wastewater treatment system.

3) The semi-dry flue gas purification system generally uses calcium oxide (CaO) or calcium hydroxide (Ca(OH) ₂ ) as raw material to prepare a Ca(OH) ₂ solution, and the Ca(OH) ₂ The solution is sprayed into the reactor and neutralized with HCl to generate neutral salt particles. The semi-dry wet purification process has a high deacidification efficiency, and the HC1 removal rate is generally about 90%, but the lime slurry preparation system is complicated, and the pipes and nozzles are easy to block.

The above three flue gas deacidification processes all use deacidification agents to neutralize HCl gas to achieve the purpose of deacidification, but a large amount of deacidification agents will be consumed during operation, and with the generation of solid waste and waste liquid, it will increase solid waste and Waste disposal costs.

In summary, the current traditional incineration process of chlorine-containing waste has the following defects:

1) It is impossible to treat high chlorine solid waste, liquid waste and gas waste at the same time.

2) High chlorine-containing organic waste cannot be completely incinerated, and hazardous waste such as slag and fly ash will be generated, and secondary treatment is required; and the incineration temperature is low, and highly toxic substances such as dioxins and furans will be produced.

3) In the traditional acid gas HCl removal process, the consumption of deacidification agent is large, the cost of chemicals is high, and the generation of solid waste and waste liquid increases the cost of waste treatment.

4) The traditional incineration process has a large amount of flue gas, low HCl content in the flue gas, and a large amount of fly ash, resulting in poor HCl absorption effect, low concentration of hydrochloric acid (about 10%), and high impurity content, which cannot be directly used or sold.

Utility model content

In view of the deficiencies in the prior art, the purpose of this utility model is to provide a high-temperature plasma resource recovery system for chlorine-containing waste, which realizes the recycling, harmlessness, reduction and stabilization of high-chlorine waste; The operation cost is low, and the market application prospect is broad.

The technical scheme that the utility model solves its technical problem adopts is:

The high-temperature plasma resource recycling system for chlorine-containing waste described in the utility model includes a sequentially connected feeding system, a plasma gasification furnace, a first-stage waste heat heat exchanger, an acid absorption system, an alkali washing tower, a secondary combustion chamber, a secondary Level waste heat exchanger, quench cooler, bag filter, flue heater, SCR catalytic tower, heat exchanger, induced draft fan and chimney.

The slag outlet of the plasma gasification furnace is also connected with the cooling device.

The acid absorption system is a circulating water absorption system, and the acid absorption system is also connected with an acid filter device.

The rear flue of the second combustion chamber is provided with an SNCR denitrification device.

Activated carbon and baking soda injection devices are installed on the pipeline between the quench cooler and the bag filter.

An online flue gas monitoring system is set on the chimney.

The process of adopting the high-temperature plasma recycling system of chlorine-containing waste comprises the following steps:

1) Transport chlorine-containing waste to the plasma gasifier through the feed system;

2) The synthetic gas produced by cracking is cooled through the first-stage waste heat exchanger;

3) The cooled synthesis gas enters the acid absorption system to absorb acid, and then enters the alkali washing tower for further deacidification;

4) The deacidified synthesis gas enters the secondary combustion chamber for combustion, and the high-temperature flue gas produced is cooled by the secondary waste heat exchanger;

5) After the flue gas after cooling enters the quencher for rapid cooling, it enters the bag filter for dust removal;

6) The flue gas after dust removal enters the flue heater to heat up;

7) The flue gas enters the SCR catalytic tower to remove nitrogen oxides in the flue gas;

8) After the flue gas treated by SCR enters the heat exchanger for heat exchange, it is drawn out by the induced draft fan and discharged into the atmosphere through the chimney.

in:

In step 1), chlorine-containing waste, coke and flux limestone are transported into the plasma gasifier through the feed system.

The temperature of the bottom melting zone of the plasma gasification furnace mentioned in step 1) reaches 1450-1600°C, and the temperature of the upper gasification zone reaches above 1200°C.

In step 5), the quench cooler is cooled by water or air, and the flue gas temperature is rapidly cooled from 500°C to 200°C within 1 second.

Preferably, the process using a high-temperature plasma resource recovery system for chlorine-containing waste specifically includes the following steps:

1) Transport chlorine-containing waste to the plasma gasifier through the feed system;

2) The plasma gasifier uses the hydroxyl radicals generated by the plasma torch to crack the organic matter into CO, CO ₂ , H ₂ , H ₂ O, HCl and other syngas at high temperature;

3) The high-temperature synthesis gas passes through the first-stage waste heat exchanger to recover the heat in the synthesis gas to generate steam products;

4) After cooling down, the synthesis gas enters the acid absorption system, completely absorbs the HCl gas in the synthesis gas into hydrochloric acid products, and obtains high-purity hydrochloric acid products through the acid filtration device, and the unabsorbed HCl in the synthesis gas enters the alkali washing tower for further neutralization and removal ;

5) Completely remove HCl and the acid gas synthesis gas enters the secondary combustion chamber for full combustion, and the high-temperature flue gas enters the secondary waste heat recovery system to obtain steam products;

6) Finally, the flue gas is discharged up to the standard through the flue gas treatment system.

Utilizing the system provided by the utility model, the chlorine-containing waste can be fully and harmlessly treated, and hydrochloric acid products can be recovered effectively, so as to realize recycling and utilization of resources. The utility model can be used for harmless treatment of high chlorine-containing wastes in industrial industries such as petroleum, chemical industry and medicine.

Compared with the prior art, the utility model has the following beneficial effects:

1) The hydroxyl radicals generated by the plasma in the plasma gasifier can fully crack the organic components in the high-chlorine waste, and the dioxin destruction rate can reach more than 99.9999%, and form small molecule syngas such as HCl and CO.

2) This system adopts the process of first gasification cracking + acid absorption, and then secondary combustion. The hydrochloric acid absorption system is set before the secondary combustion chamber. At this time, the concentration of HCl in the flue gas is higher, the acid absorption efficiency is higher, and the purity of hydrochloric acid is obtained. Higher, can reach more than 20% concentration. Through the combination of high-temperature plasma gasification melting system and acid absorption system, the recycling, harmless, reduction and stabilization of high-chlorine wastes are realized.

3) The whole system is equipped with two-stage waste heat recovery devices (that is, two-stage waste heat heat exchangers), and the heat recovery efficiency is higher.

4) After the acid is absorbed, the flue gas enters the secondary combustion chamber for more complete combustion and lower operating costs.

5) The synthesis gas treated by the second combustion chamber is basically free of chlorine-containing substances, and the heat value of the synthesis gas is relatively high, which can ensure the combustion temperature > 1100°C and the residence time > 2s, completely eliminating the conditions for the formation of dioxins.

6) The flue gas treatment system can design quenching, dust removal, denitrification and other measures according to the flue gas emission requirements to ensure that the flue gas emission meets the requirements of relevant national regulations.

7) The chlorine-containing waste is continuously fed, and it can process chlorine-containing waste such as solid, liquid and gas at the same time, and the materials are fed through different feed ports without interfering with each other and processed at the same time.

8) The acid absorption system is designed with an acid filter device to further filter the absorbed hydrochloric acid from impurities such as fly ash to ensure the quality of hydrochloric acid products.

9) The overall system has a slight negative pressure, which is controlled by a rear-end induced draft fan.

10) The technology has strong adaptability, which can not only solve the disposal problem of high chlorine-containing waste, avoid the problem of landfill of chlorine-containing waste and secondary pollution of incineration, and save landfill; but also can recycle high-purity and high-concentration hydrochloric acid, ensuring Direct production and reuse; at the same time, it effectively reduces the operating load of the back-end flue gas treatment system, greatly reduces the consumption of deacidification agent and the generation of solid waste and waste liquid, reduces the treatment cost, and has broad market application prospects.

11) The secondary combustion chamber is installed after the acid absorption system, and the flue gas after the secondary combustion chamber does not contain corrosive gases, which can be comprehensively utilized; the secondary combustion chamber is installed after the acid absorption, the amount of flue gas is small, and the investment and operation cost of the acid absorption equipment is low. Acid absorption is more efficient, resulting in higher acid concentrations.

Description of drawings

Fig. 1 is the structure schematic diagram of the high-temperature plasma recycling system of chlorine-containing waste of the present invention;

In the figure: 1. Feed system; 2. Plasma gasifier; 3. Primary waste heat exchanger; 4. Acid absorption system; 5. Alkali washing tower; 6. Second combustion chamber; 7. Secondary waste heat exchange 8. Quenching cooler; 9. Bag filter; 10. Flue heater; 11. SCR catalytic tower; 12. Heat exchanger; 13. Induced fan; 14. Chimney; 15. Cooling device; 16. Acid filter 17. SNCR denitrification device; 18. Activated carbon and baking soda injection device; 19. On-line flue gas monitoring system.

Detailed ways

Below in conjunction with embodiment the utility model is described further.

Example

As shown in Figure 1, the high-temperature plasma recycling system for chlorine-containing wastes includes a sequentially connected feed system 1, a plasma gasification furnace 2, a primary waste heat exchanger 3, an acid absorption system 4, and an alkali cleaning system. Tower 5, secondary combustion chamber 6, secondary waste heat exchanger 7, quench cooler 8, bag filter 9, flue heater 10, SCR catalytic tower 11, heat exchanger 12, induced draft fan 13 and chimney 14.

The slag outlet of the plasma gasification furnace 2 is also connected with a cooling device 15 .

The acid absorption system 4 is a circulating water absorption system, and the acid absorption system 4 is also connected with an acid filtering device 16 .

The rear flue of the second combustion chamber 6 is provided with an SNCR denitrification device 17 .

Activated carbon and sodium bicarbonate injection device 18 are arranged on the pipeline between quench cooler 8 and bag filter 9 .

The flue gas online monitoring system 19 is set on the chimney 14 .

The heat exchanger 12 is connected to the primary waste heat exchanger 3 and the secondary waste heat exchanger 7 respectively.

The process using the high-temperature plasma resource recovery system for chlorine-containing waste specifically includes the following steps:

Chlorine-containing waste liquid, chlorine-containing solid waste, and chlorine-containing waste gas enter the plasma gasifier through different feeding systems 1 . Add coke according to the calculation to ensure that the inside of the plasma gasifier 2 can reach the condition of stable gasification. The plasma gasification process belongs to anoxic gasification rather than combustion. The temperature of the melting zone at the bottom of the plasma gasification furnace 2 reaches 1450-1600°C, and the temperature of the upper gasification zone reaches above 1200°C. Coke needs to be added as a bed in the gasifier. At a reaction temperature of 1450-1600°C in the plasma gasification furnace, the inorganic matter melts into a liquid state, and at the same time, the flux limestone is added to the furnace through the feeding system 1 to adjust the shape of the slag, and the bottom of the plasma gasification furnace 2 passes through the slag discharge Enter cooling device 15 (water cooling device, also can adopt air cooling) after system is discharged, the vitrified slag after water cooling is completely nontoxic and harmless, can be used as sandstone aggregate road construction.

Plasma gasification produces syngas such as CO, CO ₂ , H ₂ , CH ₄ , and HCl. The synthesis gas coming out of the plasma gasifier 2 contains a large amount of heat energy. First, most of the heat in the synthesis gas is recovered through the first-stage waste heat exchanger 3, and then enters the acid absorption system 4 to absorb HCl, and produce >20% hydrochloric acid Refined by the acid filter device 16 to produce qualified clean hydrochloric acid products. After the acid is absorbed, it passes through the alkali washing tower 5, and the lye is used to further remove the HCl gas in the flue gas to ensure that the HCl content in the flue gas meets the emission requirements.

The temperature of the synthesis gas coming out of the plasma gasifier 2 is about 1000°C, and after passing through the first-stage waste heat exchanger 3, the temperature drops to about 250°C. After passing through the acid absorption system 4, the temperature drops to about 45°C, and after passing through the alkali washing tower 5, the temperature drops to about 40°C.

The clean synthesis gas absorbed by the acid is combusted in the second combustion chamber 6 to obtain a large amount of heat energy. The temperature of the second combustion chamber can reach above 1100℃, and the residence time of flue gas is more than 2s.

The high-temperature flue gas coming out of the second combustion chamber 6 contains a large amount of heat energy. An SNCR denitrification device 17 is installed in the rear flue of the second combustion chamber 6, and ammonia water or urea is sprayed. Remove nitrogen oxides from flue gas. The flue gas passes through the secondary waste heat exchanger 7 to recover most of the heat in the flue gas, and the temperature of the flue gas is also reduced from 1100°C to about 550°C to obtain saturated steam, and then enters the quencher 8, which uses water or air Cooling, the flue gas temperature is rapidly cooled from about 500°C to 200°C within 1s to prevent the reverse generation of dioxins.

The flue gas after quenching enters the bag filter 9, and an activated carbon and baking soda injection device 18 is installed on the pipeline entering the bag filter 9. When entering the bag filter 9, it can effectively contact with the flue gas and absorb dioxins and dioxins in the flue gas. Furan can also remove part of sulfur dioxide and other acid gases, and the fly ash is regularly sent to the plasma gasifier 2 for treatment after being collected by cloth bags.

The flue gas after dust removal enters the flue heater 10, and the temperature of the flue gas is raised from 170°C to about 230°C by natural gas or steam to meet the temperature requirement of SCR denitrification, and then the flue gas enters the SCR catalytic tower 11 to remove the flue gas again. Nitrogen oxides in the gas to ensure the emission requirements of nitrogen oxides.

Due to the high temperature of the flue gas treated by the SCR, it enters the heat exchanger 12 for heat exchange, and heats the soft water entering the first-stage waste heat exchanger 3 and the second-stage waste heat exchanger 7 (inlet water temperature is normal temperature 25 ° C), and the The flue gas temperature drops below 130°C. Keep the temperature above the dew point temperature of the flue gas, that is, the flue gas temperature is above 110°C to prevent condensation corrosion and white smoke generation.

Preferably, a deaerator is provided on the pipeline between the heat exchanger 12 and the first-stage waste heat exchanger 3 and the second-stage waste heat exchanger 7 .

Then through the induced draft fan 13, the induced draft fan 13 ensures that the whole system is a negative pressure system, ensuring that the flue gas will not be discharged outwards through the flue and equipment, and the flue gas will be discharged into the atmosphere through the chimney 14. To monitor the flue gas emission data, an online flue gas monitoring system 19 is installed on the chimney to monitor the flue gas emission data in real time and transmit the data directly to the Environmental Protection Bureau. The treated flue gas is discharged into the atmosphere, and the emission concentration and rate of the polluting gas to the environment are lower than the emission standards stipulated by the relevant national standards.

In this case, the back-end flue gas treatment system will be adjusted according to the revision of relevant national standards and regulations to meet the emission requirements of relevant national standards and regulations. The front-stage high-temperature plasma gasifier 2 decomposes the organic components of high-chlorine waste into CO, CO ₂ , H ₂ , H ₂ O, HCl and other synthesis gases, and recovers HCl through the acid absorption system 4 to produce high-concentration hydrochloric acid; The inorganic components of chlorine waste are melted at high temperature to obtain non-toxic and harmless vitrified slag, which can be used as sand and gravel aggregate, so as to realize the resourceful and harmless utilization of high chlorine-containing waste, and effectively reduce project operating costs.

Claims (6)

1. A high-temperature plasma resource recovery system for chlorine-containing waste, characterized in that it includes a sequentially connected feed system (1), a plasma gasifier (2), a first-stage waste heat exchanger (3), and an acid absorption System (4), alkali washing tower (5), secondary combustion chamber (6), secondary waste heat exchanger (7), quench cooler (8), bag filter (9), flue heater (10), SCR catalytic tower (11), heat exchanger (12), induced draft fan (13) and chimney (14). 2. The high-temperature plasma resource recovery system for chlorine-containing waste according to claim 1, characterized in that: the slag outlet of the plasma gasification furnace (2) is also connected to a cooling device (15). 3. The high-temperature plasma resource recovery system for chlorine-containing waste according to claim 1, characterized in that: the acid absorption system (4) is a circulating water absorption system, and the acid absorption system (4) is also connected with an acid filter device (16) CONNECTED. 4. The high-temperature plasma resource recovery system for chlorine-containing waste according to claim 1, characterized in that: the rear flue of the second combustion chamber (6) is provided with an SNCR denitrification device (17). 5. the chlorine-containing waste high-temperature plasma resource recovery system according to claim 1 is characterized in that: activated carbon and sodium bicarbonate injection device ( 18). 6. The high-temperature plasma resource recycling system for chlorine-containing waste according to claim 1, characterized in that an online flue gas monitoring system (19) is set on the chimney (14).