CN201059564Y - A device for gas-controlled medical waste incineration in a rotary kiln - Google Patents

Abstract

The utility model relates to a device for gas-controlled medical waste incineration in a rotary kiln, which relates to the technical field of environmental protection. The primary combustion chamber of the rotary kiln of the utility model is provided with a primary blower fan and an auxiliary fuel inlet 1 connected to the control chamber for air-controlled anoxic combustion. The secondary combustion chamber is provided with a secondary air blower connected to the control room for air-controlled oxygen-enriched combustion and an auxiliary fuel inlet 2. The transition section at the joint joint between the secondary combustion chamber and the primary combustion chamber of the rotary kiln is provided with a reduced-diameter vortex flow structure in the shape of an impeller. The ash well at the lower part of the second combustion chamber is provided with a post-combustion furnace grate, and the post-combustion furnace grate is connected with an ember blower. There is an ash discharge mechanism at the bottom of the supplementary combustion furnace grate, and a water-cooled ash bin with a scraper discharger is installed under the ash discharge mechanism. Compared with the prior art, the utility model has the advantages of good operating economic performance, automatic and safe continuous feeding, smooth slag discharge system and low pollution discharge index.

Description

A device for gas-controlled medical waste incineration in a rotary kiln

technical field

The utility model relates to the technical field of environmental protection, in particular to a device for gas-controlled incineration of medical waste using a rotary kiln.

Background technique

At present, the number of beds in medical institutions at all levels in the country is about 3.177 million, and the daily medical waste generated nationwide is as high as 1880-2800 tons. In order to safely and properly dispose of these toxic and hazardous wastes, the state has clearly formulated guidelines for the use of special recycling and centralized incineration of medical wastes, so the technology of harmless incineration of medical wastes has developed rapidly.

Medical waste contains a large number of pathogens and bacteria, and its strict incineration technology requires that the entire bag must be sealed and fed to prevent harmful leachate pollution in medical waste and threaten human health, and to achieve safe combustion.

In my country, the rotary kiln incinerator is selected as one of the main types of incineration of medical hazardous waste, especially suitable for the incineration system of commercial centralized treatment plants. The rotary kiln incinerator has high-strength destruction of toxic pollutants and good adaptability to the size and shape of waste materials. However, the existing rotary kiln incineration technology still has the following deficiencies:

a) Failure to suppress the generation of pollutants from combustion. Both the rotary kiln and the second combustion chamber are oxygen-enriched combustion, the air excess coefficient is high, and the economic performance of combustion is poor. The local high temperature in the rotary kiln and the high flue gas flow rate entrain a large amount of fine particles. Combustion material is oxygen-enriched combustion in the kiln. In order to maintain a certain high temperature in the secondary combustion chamber and ensure that the flue gas lasts at this high temperature for more than 2 seconds, a certain amount of auxiliary fuel oil must be invested, which makes the operating cost higher.

b) Limitations of the feed system. Some feeding systems adopt impeller-type bag tearing machine crushing mechanism. When there are many types of waste in the sealed bag, especially some scalpels, needles, and thin sharp utensils are difficult to crush. The danger is unimaginable. Some feeding systems use air-lock impeller feeders, which cannot meet the automatic and safe feeding of medical waste. The limitation of the above-mentioned feeding system is that automatic, safe and continuous feeding of medical waste cannot be realized by either the funnel or the impeller feeding system.

c) The rotary kiln incinerator adopts oxygen-enriched combustion, glass melting often occurs in the rotary kiln, and the secondary combustion chamber is seriously hung. Damage to the refractory material of the rotary kiln seriously affects the operation of the slag discharge system, and it is often necessary to stop the furnace to clean the coke.

Contents of the invention

Aiming at the deficiencies in the above-mentioned prior art, the purpose of this utility model is to provide a device for incinerating medical waste with air control in a rotary kiln. It has the advantages of good operating economic performance, automatic and safe continuous feeding, smooth slag discharge system and low pollution emission indicators. It is suitable for the construction of large-scale centralized disposal centers for medical waste and hazardous waste.

In order to achieve the above-mentioned purpose of the invention, the technical solution of the utility model is realized in the following manner.

A device for gas-controlled medical waste incineration in a rotary kiln, which includes a feeding mechanism composed of a wheeled trash can and a chain hoist, a feeding hopper, a hydraulic piston push rod connected to the feeding hopper, The interlocking and closed feeding mechanism composed of hydraulic pressure plate door and hydraulic fire door, the primary combustion chamber of the rotary kiln connected with the feeding mechanism, and the secondary combustion chamber which is movable and tightly embedded with the primary combustion chamber of the rotary kiln are connected with the secondary combustion chamber in sequence Waste heat boilers, quench towers, absorption towers, bag filters, induced draft fans and chimneys. Its structural feature is that the primary combustion chamber of the rotary kiln is provided with a primary fan for air-controlled anoxic combustion in a control room connected to it and an auxiliary fuel inlet. The secondary combustion chamber is provided with a secondary fan connected to the control room for air-controlled oxygen-enriched combustion and an auxiliary fuel inlet 2. The transition section at the joint joint between the secondary combustion chamber and the primary combustion chamber of the rotary kiln is provided with a reduced-diameter vortex flow structure in the shape of an impeller. The ash well at the lower part of the second combustion chamber is provided with a post-combustion furnace grate, and the post-combustion furnace grate is connected with an ember blower. There is an ash discharge mechanism at the bottom of the supplementary combustion grate, and a water-cooled ash bin with a scraper discharger is installed under the ash discharge mechanism.

In the above device, the upper end of the secondary combustion chamber is provided with a bypass flue with a safety valve.

In the above device, the absorption tower is provided with a slaked lime injector connected thereto, and the material is fed into the absorption tower by compressed air from a slaked lime silo. The connecting section between the absorption tower and the bag filter is equipped with an activated carbon injector connected to it, and the material is supplied from the activated carbon warehouse and is also input into the flue of the connecting section through compressed air.

In the above device, the rotary furnace wall of the initial combustion chamber of the rotary kiln is built with a heat insulating layer and a refractory layer. An anchor piece connected with the furnace wall is placed between the refractory layer and the heat insulation layer.

In the above device, the inner wall of the refractory layer at the inlet end of the rotary furnace wall of the primary combustion chamber of the rotary kiln is evenly distributed with a plurality of protrusions functioning as lifting plates.

Compared with the prior art, the utility model has the following advantages:

a) Air-controlled anoxic combustion in the rotary kiln, the air excess coefficient is less than 1, and the gas CO, H ₂ , CH ₄ , C ₂ H ₄ with a certain calorific value is formed and enters the second combustion chamber to continue burning. The advantages of gas-controlled incineration are: less auxiliary fuel consumption, less NOx generation, less particulate matter emissions, and less heavy metal emissions.

b) The transition section between the rotary kiln and the second combustion chamber is equipped with a reduced-diameter vortex flow structure in the shape of an impeller, and the combustion-supporting design with double burners tangential air distribution is adopted in the second combustion chamber to realize turbulent combustion. The secondary combustion chamber is maintained at a high temperature environment of 900°C-1100°C, completely avoiding the damage of dioxin precursors such as chlorobenzene and chlorophenol.

c) The inner wall of the refractory layer at the inlet end of the rotary kiln is evenly distributed with 2-3 longitudinal special-shaped protrusions. This structure can ensure that the material is fully rolled and stirred during the rotation of the rotary kiln cylinder, and prevents slipping and agglomeration, so that the combustion is fully and completely , to avoid high temperature local slagging in the furnace.

d) Medical waste is collected in reusable wheeled collection buckets which dump the waste into the hopper with the assistance of a chain hoist. Then, the feeding system uses a combination of hydraulic piston push rod, hydraulic pressure plate door and hydraulic fire door to send the waste into the primary combustion chamber of the rotary kiln, realizing automatic, closed and continuous feeding of medical waste.

e) The tail purification system adopts flue gas water spray quenching and dry absorption tower technology, which effectively inhibits the generation and emission of dioxins, and at the same time absorbs dust, heavy metals and activated carbon particles in the flue gas.

The utility model will be further described below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1 is the overall structural representation of the utility model;

Fig. 2 is the structural representation of the feeding mechanism of the utility model;

Fig. 3 is a schematic diagram of the direction A of Fig. 2;

Fig. 4 is a schematic diagram of a reduced-diameter vortex flow structure arranged at the transition section of the movable joint between the primary combustion chamber and the secondary combustion chamber of the rotary kiln of the present invention;

Fig. 5 is the B-B direction schematic diagram of Fig. 4;

Fig. 6 is a schematic cross-sectional view of the rotating furnace wall of the rotary kiln initial combustion chamber of the utility model;

Fig. 7 is a schematic cross-sectional view of the inlet end of the rotary furnace wall of the rotary kiln initial combustion chamber of the utility model.

Detailed ways

Referring to Fig. 1 to Fig. 7, the utility model includes a feeding mechanism composed of a wheeled trash can 0 and a chain hoist 2, a feed hopper 3, a hydraulic piston push rod 1 connected with the feed hopper 3, a hydraulic The interlocking and closed feeding mechanism composed of the pressure plate door 33 and the hydraulic fire door 34, the rotary kiln primary combustion chamber 4 connected with the feeding mechanism, the secondary combustion chamber 5 which is movable and airtightly embedded with the rotary kiln primary combustion chamber 4, and the secondary combustion chamber 5 Room 5 is connected in turn with waste heat boiler 17, quench tower 18, absorption tower 19, bag filter 24, induced draft fan 25 and chimney 26. The primary combustion chamber 4 of the rotary kiln is provided with a primary blower 8 and an auxiliary fuel inlet 9 connected to it in the control room for air-controlled anoxic combustion. The rotating furnace wall of the primary combustion chamber 4 of the rotary kiln is built with a heat insulation layer 4-4 and a refractory layer 4-5, and an anchor piece 4 connected to the furnace wall is placed between the refractory layer 4-5 and the heat insulation layer 4-4 -2, the inner wall of the refractory layer 4-5 at the inlet end of the rotary furnace wall of the primary combustion chamber 4 of the rotary kiln is evenly distributed with a plurality of protrusions 4-1 which function as lifting plates. The second combustion chamber 5 is provided with a secondary air blower 10 and an auxiliary fuel inlet 11 connected to it in the control room for air-controlled oxygen-enriched combustion. The transition section between the secondary combustion chamber 5 and the primary combustion chamber 4 of the rotary kiln is provided with a reduced-diameter vortex flow structure 30 in the shape of an impeller, and the upper end of the secondary combustion chamber 5 is provided with a bypass flue 7 with a safety valve 6 . The second combustion chamber 5 lower ash well places are provided with supplementary combustion furnace grate 12, and supplementary combustion furnace grate 12 places are connected with burner fan 14. The bottom end of the post-combustion grate 12 is provided with an ash discharge mechanism 13, and a water-cooled ash bin 15 with a scraper discharger 16 is provided below the ash discharge mechanism 13. Absorption tower 19 is provided with the slaked lime ejector 21 that is connected with it and is fed in the absorption tower 19 by the slaked lime storehouse 20 feed through compressed air; The activated carbon storehouse 22 feed also enters the connecting section flue through compressed air.

The incineration process step of the utility model device is:

① As shown in Figure 2 and Figure 3, the unopened whole package of medical waste garbage bags are collected by the wheeled garbage bin 0, then lifted by the chain elevator 2 and sent to the feed hopper 3, and the water-cooled casing is used to cool the feed Bucket 3 prevents the binding of garbage bags. The wheeled garbage bin 0 returns along the chain hoist 6 and sends a signal through the electrical control system. After a delay for a period of time, the hydraulic pressure plate door 33 turns from the vertical position to the horizontal position to compress the garbage bag, and then the hydraulic fire door 34 opens. The hydraulic piston push rod 1 pushes the garbage bag into the primary combustion chamber 4 of the rotary kiln. After the hydraulic piston push rod 1 completes a stroke reset, the hydraulic fire door 34 is closed, and the hydraulic pressure plate door 33 is opened to a vertical position to complete a feeding operation. The primary fan 8 enters the primary combustion chamber 4 of the rotary kiln from the front end of the primary combustion chamber 4 of the rotary kiln. The medical waste and the introduced wind are assisted by the auxiliary fuel oil entering from the auxiliary fuel oil inlet 9, and the air excess coefficient is controlled to be less than 1 to complete the medical treatment. Drying, pyrolysis and gas-controlled anoxic combustion processes of waste. When the primary combustion chamber 4 of the rotary kiln is in normal operation, supplementary combustion of auxiliary fuel is not required, and the auxiliary fuel inlet 9 is automatically switched according to the temperature change in the primary combustion chamber 4 of the rotary kiln. The outlet temperature of the rotary kiln is between 760°C and 960°C.

②The flue gas and part of the toxic and harmful substances produced in the primary combustion chamber 4 of the rotary kiln enter into the secondary combustion chamber 5 through the transitional diameter-reduced vortex flow structure 30 in the secondary combustion chamber 5 that is tightly embedded with its activities for gas control. Oxygen-enriched combustion is complete. The two auxiliary fuel oil inlets 11 of the second combustion chamber 5 are respectively controlled by two burners, and each burner can adopt multi-stage fire variable load, and the load size is controlled and automatically adjusted according to the flue gas temperature in the second combustion chamber 5, In order to ensure that the heat loss rate of the bottom ash is lower than 4%. The temperature in the second combustion chamber 5 can reach 900°C-1200°C, no auxiliary fuel oil is needed during normal operation, and the auxiliary fuel oil inlet 2 11 is closed. The wind introduced by the secondary air blower 10 supplements the combustion air in the secondary combustion chamber 5, and the air excess coefficient is controlled to be greater than 1 to increase the disturbance of the airflow in the secondary combustion chamber 5. The bottom ash containing a small amount of residual charcoal produced during the combustion process is burned in the inclined grate 12 provided in the ash well at the lower part of the second combustion chamber 5, and the remaining ashes are discharged into the water-cooled ash bin 15 through the turning plate type ash outlet mechanism 13, and then discharged by the The discharge machine 16 with scraper is taken out. If the waste taken out does not meet the leaching toxicity index, the cement must be solidified before being landfilled. The upper end of the second combustion chamber 5 is provided with a bypass flue 7 with a safety valve 6, which can ensure that the tail purification equipment is free from damage when an accident occurs in the system.

③The flue gas at the outlet of the second combustion chamber 5 is cooled to 500°C through the waste heat boiler 17, and part of the energy is recovered for waste heat utilization. When the flue gas enters the quench tower 18, the temperature is rapidly cooled to below 200°C by spraying atomized water, avoiding the low-temperature synthesis reaction zone of dioxin and fly ash, and effectively inhibiting the regeneration of dioxin. The cooled flue gas enters the absorption tower 19 for dry deacidification, and at the same time, the slaked lime in the slaked lime bin 20 is fed into the absorption tower 19 by the slaked lime ejector 21 through compressed air to remove SO2, HCl and other acid gases in the flue gas . The activated carbon in the activated carbon bin 22 is fed into the connecting section between the absorption tower 19 and the bag filter 24 by the activated carbon injector 23 through compressed air, and absorbs a small amount of dioxins contained in the flue gas. The low-pressure pulse-jet bag filter 24 collects particulate matter and activated carbon in the flue gas, and captures heavy metals therein. The fully purified flue gas is discharged into the atmosphere by the induced draft fan 25 through the chimney 26 .

The excellent combustion performance of the primary combustion chamber 4 of the rotary kiln requires some operating experience or parameter design guarantees to achieve 3T combustion with high temperature, sufficient residence time and strong turbulent disturbance. After engineering practice, the utility model determines the following design criteria to ensure turbulent combustion:

●Average gas velocity U=4±30% (m/s)

●Volume heat load Qv＝(2.5±0.5)×105(Kcal/m3hr)

●Speed limit 5×10-4<Fr<2×10-2 (Fr=w2R/g, w=2πn/60)

●Volume share of waste in the kiln Γ=15±5(%)

For medical waste, the aspect ratio of the initial combustion chamber of the rotary kiln is 5<L/D<8

Claims (5)

1. device that is used for rotary kiln Pneumatic-control type medical wastes incineration, it comprises by wheeled dustbin (0), the feed mechanism that chain elevator (2) is formed, by feed hopper (3), the hydraulic piston push rod (1) that is connected with feed hopper (3), hydraulic platen door (33), the feeding mechanism of the chain sealing that hydraulic pressure vent (34) is formed, the rotary kiln that is connected with feeding mechanism just fires chamber (4), just fire the dual firing chamber (5) of the movable airtight interlocking in chamber (4) with rotary kiln, the waste heat boiler (17) that is connected successively with dual firing chamber (5), quench tower (18), absorption tower (19), sack cleaner (24), air-introduced machine (25) and chimney (26), it is characterized in that, described rotary kiln just fires primary air fan (8) and the auxiliary fuel import one (9) that chamber (4) is provided with gas control anoxycausis in the connected control room, described dual firing chamber (5) is provided with the overfire air fan (10) and the auxiliary fuel import two (11) of gas control oxygen-enriched combusting in the connected control room, dual firing chamber (5) is provided with the undergauge vortex flow structure (30) that is shaped as impeller with the changeover portion that rotary kiln just fires the movable scarf in chamber (4), the bottom ash Jing Chu of dual firing chamber (5) is provided with afterburning grate (12), afterburning grate (12) is located to be connected with and is burnt blower fan (14), the bottom of afterburning grate (12) is equipped with ash discharge mechanism (13), is equipped with the water-cooled ash storehouse (15) of belt scraping plate discharging machine (16) below the ash discharge mechanism (13).

2. according to the described device that is used for rotary kiln Pneumatic-control type medical wastes incineration of claim 1, it is characterized in that the upper end of described dual firing chamber (5) is provided with the bypass flue (7) of band safety valve (6).

3. according to claim 1 or the 2 described devices that are used for rotary kiln Pneumatic-control type medical wastes incineration, it is characterized in that described absorption tower (19) are provided with connected calcium hydroxide injector (21) and are imported in the absorption tower (19) by compressed air by calcium hydroxide storehouse (20) feed; Absorption tower (19) is provided with connected activated carbon eductor (23) and also imports the linkage section flue by compressed air by active carbon storehouse (22) feed with sack cleaner (24) linkage section.

4. according to the described device that is used for rotary kiln Pneumatic-control type medical wastes incineration of claim 3, it is characterized in that, the rotation furnace wall that described rotary kiln just fires chamber (4) is built-in with thermal insulation layer (4-4) and flame retardant coating (4-5), is equipped with the anchoring piece (4-2) that is connected with the furnace wall between flame retardant coating (4-5), thermal insulation layer (4-4).

5. according to the described device that is used for rotary kiln Pneumatic-control type medical wastes incineration of claim 4, it is characterized in that flame retardant coating (4-5) inner wall even distribution that described rotary kiln just fires the rotation furnace wall entrance point of chamber (4) has had a plurality of projectioies (4-1) of lifting blade effect.

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