RU2645057C1 - Method of recycling medical and biological waste - Google Patents

Abstract

FIELD: processing and recycling of waste.

SUBSTANCE: invention relates to thermal recycling of organo-containing wastes. Technical result is achieved by loading wastes into a combustion chamber with a mechanised loading device through a sluice rotary tray, which prevents flue gas from escaping into the environment. Processes of drying, thermal decomposition and combustion are combined: wastes are dried and partially pyrolysed on a rotary tray at the top of the recycling chamber while simultaneously burning the solid residue in the bottom part of the recycling chamber. Thermal balance of said process organisation is positive, so there is no need to use external fuel, and the duration of the process is halved. Environmental safety is achieved due to the firing of gaseous products in the afterburner, their cleaning from solid inclusions in a cyclone, washing in a wet scrubber and carrying out the process under constant vacuum.

EFFECT: thermal, environmentally safe recycling of medical and biological wastes, higher capacity of the installation.

1 cl, 3 dwg

Description

The invention relates to the field of thermal utilization of medical and biological waste.

A known method and installation for its implementation (cremator KD-50), in which the waste is burned in the combustion chamber of the cremator, equipped with a burner, a loading hatch and a chimney [1].

The disadvantage of this method is the dependence of productivity on the dimensions of the cremator, since it works in cycles - a one-time loading of the installation with the material to be destroyed, heating, burning, cooling of the installation, unloading the ash residue.

The disadvantage of this method is that when each newly loaded portion of “cold” biological material is heated, “dirty” emissions (first water vapor, then the initial products of thermal decomposition, etc.) get into the atmosphere, since their neutralization at initial low temperatures is impossible , and additional flue gas cleaning is not performed.

Another disadvantage of this method is the lack of a system for using the thermal potential of the organic component of the waste and fuel burned in the burner and, as a result, the temperature of the flue gases at the outlet of the chimney is unacceptably high.

Another disadvantage of this method is that the combustion process is carried out at an overpressure in the combustion chamber, as a result of which combustion products and dangerous pathogenic components can enter the environment.

A known method of cremation and a device for its implementation [2], including pre-heating the cremation chamber, placing disposable materials in it and burning them by exposure to a burner flame, thermal radiation of the walls and air flow, followed by afterburning of exhaust gases.

The disadvantage of this method is the complex process control algorithm, which provides for the sequential drying of the object and its burning by changing the temperature in the cremation chamber, the burner operating mode and redirecting the air flow for 10-20 minutes sequentially: to the upper part of the combustion chamber, then to the upper and lower parts and finally to the bottom of the camera.

Another disadvantage of this method is the cyclical organization of the recycling process, as a result of which an increase in productivity is possible only by increasing the volume of the combustion chamber and the number of burner devices, which, in turn, leads to an increase in the dimensions and weight of the installation and an increase in fuel consumption.

Another disadvantage of this method is the manual loading of waste into the combustion chamber through an open loading hatch, requiring significant physical exertion and prolonged exposure to personnel when residual gases along with harmful components enter the atmosphere.

Closest to the invention is a disposal method carried out in a plant for the thermal destruction of solid biological waste [3], comprising a combustion chamber equipped with a loading hatch and a burner device, an afterburner equipped with a burner device, a heat exchanger, a gas purification system, a smoke exhauster and a chimney.

The disadvantage of this method is the lack of a lock system when loading waste, as a result of which when opening the hatch into the atmosphere, flue gases freely escape from the internal volume of the installation, capturing dangerous pathogenic organisms that may be on the waste loaded at that moment.

The disadvantage of this method is the lack of mechanized loading of waste, the consequence of which is the difficulty of complying with safety requirements for manual loading of waste, accompanied by the active emission of flue gases from the open loading hatch.

Thus, the common disadvantages of the known devices are: the lack of locking systems when loading new portions of recyclable material, which results in the free exit of gaseous products from the disposal chamber into the environment, and the lack of mechanized loading of waste, which makes it difficult to comply with safety requirements for manual loading waste, accompanied by the active emission of flue gases from the open loading hatch and underutilization of the thermal potential waste, resulting in increased fuel consumption.

The technical result, to which the proposed method of waste disposal is directed, is to increase the shift productivity of the equipment, reduce the specific fuel consumption by using the heat potential of the waste and ensure the environmental safety of the environment and maintenance personnel.

The technical result is achieved in that the waste is loaded into the recycling chamber by a mechanized loading device through a rotary lock tray, the drying, thermal decomposition and incineration processes are combined: the waste is dried and partially pyrolyzed on the rotary tray in the upper part of the recycling chamber, while burning solid residue in the lower part recycling chambers; water vapor, gaseous pyrolysis products and flue gases are subjected to fire neutralization in the afterburner, cooled in the heat exchanger, cleaned of solid inclusions in the cyclone, eliminate odors in the adsorber, washed in a wet scrubber and put into the atmosphere through the chimney, and the whole process is carried out under constant vacuum created by the exhaust fan.

The essence of the proposed technical solution is illustrated by drawings, where in FIG. 1 is a schematic diagram of an installation; FIG. 2 is a longitudinal section through a disposal chamber; FIG. 3 is a cross-sectional view of a disposal chamber.

The installation comprises a loading device 1, including a receiving box 2, connected by a rigid rod 3 with a loading hatch 4, equipped with a drive 5; a disposal chamber 6, the lower part of which is a combustion zone 7 provided with a burner 8, and the upper part is a drying and oxidation pyrolysis zone 9 with a rotary tray 10 provided with a drive 11; afterburning chamber 12 with a burner 13 and a secondary air input system 14; catalytic afterburner cartridge 15; heat exchanger 16; cyclone 17; adsorber 18; wet scrubber 19; smoke exhauster 20 and chimney 21.

Installation works as follows.

The rotary tray 10 is set to the "bottom down" position and the loading hatch is closed 4. The burners 8 and 13 are turned on and the installation is heated to the operating temperature in the combustion zone of 700-900 ° C. A portion of the waste is placed in the receiving box 2. Turn on the drive 5 of the loading hatch 4 (turning on the drive 5 is only possible when the rotary tray 10 is “bottom down”) and the waste is moved to the rotary tray 10, after which the hatch 4 is closed. The drive 11 of the rotary tray 10 is turned on and the tray 10 is first transferred to the “bottom up” position and then returned to its original position “bottom down”. After the start of waste burning in the combustion zone 7, a new portion of waste is loaded into the rotary tray 10 and the tray is moved to the intermediate position - the “bottom is vertical”. Due to the radiation from the combustion zone and the convection of gases, the waste in the tray 10 first loses moisture, and then the process of thermal decomposition begins (oxidative pyrolysis). The resulting gaseous products due to the draft of the smoke exhauster 20, migrating to the exit of the combustion zone 7 through a high-temperature combustion zone in its lower part, are subjected to primary fire neutralization and enter the afterburning chamber 12, where in the regime of a rotating gas flow due to high turbulence, high relative speeds and During their stay, high-quality combustion of the combustible components of the pyrolysis gas and solid particles (dust extractor) is ensured. The resulting flue gases are subsequently sucked through the cartridge of the catalytic afterburner 15, where low-temperature oxidation of the residues of organic compounds takes place, the heat exchanger 16, where the temperature of the gases is reduced to the level of 150-120 ° C, and enters the gas purification system. In the gas purification system, the flue gases are first cleaned of dust in the “dry” cyclone 17, odors are eliminated in the adsorber 18, and then the liquid is flushed in the “wet” scrubber 19. The cleaned flue gases enter the smoke exhauster 20 and are released into the atmosphere through the chimney 21.

After the main process of burning the waste portion in the combustion zone 7 is completed, the rotary tray 10 is turned to the “bottom up” position, the waste is dumped onto the burning center in the lower part of the combustion zone 7, the rotary tray 10 is returned to the “bottom down” position and a new portion is loaded into it waste. Further cycles are repeated.

Dust unloading from cyclone 17 is performed as it accumulates. The collection and unloading of the spent adsorbent from the adsorber 18 and sludge from the scrubber 19 is carried out after the end of the change into textile or plastic bags, with which they are subsequently disposed of in the combustion zone 7. The ash remaining after combustion of the organic component of the waste is discharged from the grate once shift. The operation of the entire process chain under the vacuum created by the smoke exhauster 20, located at the outlet of the installation, eliminates the possibility of the release of harmful components into the atmosphere.

Example. Within 1 h, 100 kg of waste with an initial moisture content of 65% is disposed of. The unit is preheated to operating temperature.

With the known method of cremation for the burning of 100 kg of waste with a moisture content of 65%, 16 liters of diesel fuel are consumed, i.e. ~ 130,000 kcal. The process is carried out in the following sequence: 1st stage (30 min) - heating and drying of waste. The process is endothermic, external fuel costs ~ 46000 kcal. 2nd stage (30 min) - burning solid residue. The process is exothermic, the release of the thermal potential of the organic mass is ~ 122500 kcal, but this heat released during combustion during the 2nd stage is removed from the disposal chamber 6 with flue gases and is not used for the disposal process. At the same time, external fuel is constantly used - during the 1st stage to carry out drying and heating processes and, in part, during the 2nd stage to maintain the temperature level. Thus (excluding heat loss), 282500 (160000 + 122500) kcal is introduced into the process, and 46000 kcal (16.1%) is useful.

In the inventive method, with the same amount of waste, most of the heat generated during the combustion of the dry residue (122500 kcal) is used to dry a new portion of the waste located in the rotary tray in the upper, hottest zone. The degree of “drainability” of the waste depends on the residence time of the waste in the drying zone, which, in turn, depends on the rate of combustion of the solid residue and the heat exchange conditions between the combustion and drying zones, but in any case there is a positive heat balance (122500 is much more than 46000) . In this case, external fuel is consumed only for heating the installation and maintaining the set temperature regime during unforeseen stops. The process time is halved.

Gaseous products released during drying and subsequent thermal decomposition (pyrolysis) sequentially pass through two high-temperature zones - the combustion zone in the disposal chamber and the afterburner, which increases the level of their fire neutralization.

In this way:

The task of increasing the shift productivity of equipment and reducing specific fuel consumption is achieved by combining several technological stages in one cycle: heating and drying of each new portion of the waste occurs due to the thermal potential of the solid residue burned at the same time from the previous portion. The heat balance of this process organization is positive, so there is no need to use external fuel, and the process time is halved.

The task of ensuring environmental safety of the environment in the proposed method is achieved due to the fact that, firstly, the proposed method involves loading the waste into the installation through a rotary lock tray, which eliminates the possibility of flue gases entering the environment. Secondly, environmental safety in the inventive method is achieved due to the fact that the gaseous products released during oxidative pyrolysis and combustion are first subjected to partial fire neutralization in the combustion zone, then to complete fire neutralization in the afterburner, and after their cooling in the heat exchanger, to comprehensive cleaning in the gas cleaning system.

Loading waste loading device facilitates the work of staff.

Carrying out the process under the vacuum created by the smoke exhauster makes it impossible for harmful components to escape into the environment.

In this way:

The combination of these essential features provides the opportunity for environmentally safe thermal disposal of medical and biological waste, allows you to mechanize the loading process, which significantly reduces physical workloads for staff and improves working conditions, provides the facility with continuous operation and an increase in its shift capacity, provides a more complete use of thermal potential waste and fuel economy and ensures environmental safety owls into the environment.

Tests of the installation sample in real conditions showed a high degree of neutralization of toxic components of the exhaust gases, the absence of smoke and odor in the working room. Significant fuel economy has also been achieved.

Information sources

1. Installation for thermal utilization of biological waste (cremator KD-50) // http://www.agro-kem.ru/.

2. The method of cremation and a device for its implementation // RF Patent No. 21110016.

3. Installation for the thermal destruction of solid biological waste // RF Patent No. 118027.

Claims (1)

A method for the disposal of medical and biological waste, including loading the waste into the combustion chamber, heating and burning it, additionally heating the combustion products in the afterburner and exhausting the flue gases into the atmosphere through the chimney, characterized in that the waste is loaded into the recycling chamber through a mechanized loading device through lock rotary tray, drying, thermal decomposition and incineration processes combine: the waste is dried and partially pyrolyzed on the rotary tray in the upper part of the recycling chamber and simultaneously burning the solid residue at the bottom of disposal chamber; water vapor, gaseous pyrolysis products and flue gases are subjected to fire neutralization in the afterburner, cooled in the heat exchanger, cleaned of solid inclusions in the cyclone, eliminate odors in the adsorber, washed in a wet scrubber and put into the atmosphere through the chimney, and the whole process is carried out under constant vacuum created by the exhaust fan.

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