RU2165050C2 - Mobile unit for burning radioactive waste and dangerous bioobjects - Google Patents

Abstract

FIELD: environment control; burning solid combustion radioactive waste and dangerous bioobjects. SUBSTANCE: unit includes casing of combustion chamber, combustion chamber with coarse filter arranged inside it, air supply unit, gas discharge main, fine filter and gas receiving unit with exhaust device. Coarse filter is arranged inside combustion chamber in such way that it closes its gas exhaust opening; bottom of combustion chamber is made in form of metal plate with through slot-shaped narrowing passages arranged across this plate in parallel rows; this bottom is also provided with through cylindrical passages where pointed pins-with air supply passages inside them are mounted in parallel rows projecting above surface of metal plate. EFFECT: extended field of application; increased coefficient of reduction of volume of bioobjects being burnt; increased productivity per burning cycle; enhanced operational reliability. 3 dwg

Description

 The inventive object relates to the field of environmental protection, and more specifically to the field of processing solid combustible radioactive and hazardous wastes, and is a mobile device, which, if necessary, using conventional vehicles, can be transported from one destination to another. The most effectively claimed device can be used for burning radioactive and dangerous biological objects (corpses, skeletons of animals) that died as a result of any disaster (from radioactive and toxic substances, infectious diseases or as a result of radiation exposure).

 A device for burning hazardous biological objects (animal corpses) [1], including a combustion chamber having end and opposite side walls, as well as the main fuel nozzle located in the end wall, is known. The first cover is pivotally connected to the upper part of one of the end walls of the combustion chamber with an opening made in it, to which a vertical chimney is connected with an exhaust gas afterburner built into it, equipped with an auxiliary fuel nozzle, which is connected by the fuel pipe to the main fuel nozzle of the combustion chamber. Two second covers are pivotally attached to the upper parts of the opposite side walls, and in the closed position all three covers tightly overlap the upper part of the combustion chamber.

The disadvantages of the known device are:
- the unreliability of the operation, due to the possibility of stopping it, due to the "failure" of the flame (spontaneous cessation of fuel combustion), characteristic of all types of fuel burners, which include fuel nozzles;
- a reduced coefficient of reduction in the volume of the burned bioobject due to the lateral location in the end wall of the combustion chamber of the main fuel nozzle, which does not provide an even distribution of heat from the burned fuel throughout the volume of the combustion chamber, as well as the absence of a unit for supplying a gaseous oxidizer in the device.

 A mobile device for burning hazardous biological objects (bodies of infectious animals) [2], including a combustion chamber with an inclined hearth having openings for air supply, is known. Above the inclined hearth there is a grate with a fuel (vertically annular) burner equipped with a flame divider, above which, in turn, there is a grate for laying combustible biological objects. In the lid of the combustion chamber there is a loading hatch and a chimney.

 A disadvantage of the known device is the reduced reliability of its operation, due to the possibility of stopping the device due to the cessation of the intake of air in the combustion chamber and / or the cessation of fuel combustion in the fuel burner due to clogging with solid products of the biological object burning of holes for air and / or channel of the fuel burner. This drawback is due to the location of the holes for the air supply and the fuel burner under the grate for laying combustible biological objects. In addition, the unreliability of the known device due to the possibility of "failure" of the flame in the fuel burner.

 Closest to the technical nature of the claimed device is a mobile device for burning hazardous biological objects (animal remains) that died as a result of any disaster [3], including a combustion chamber, consisting of two end, four side walls, a cover and a bottom, located the lower half in the casing of the combustion chamber (support box).

 Part of the cover of the combustion chamber with one of the upper side walls of the combustion chamber adjacent to it is hinged and is a hinged cover of the loading opening of the combustion chamber. In the upper part of the end walls, gas vents are made, interconnected by a gas outlet connected to a gas discharge unit (chimney).

 Inside the combustion chamber above its bottom there is a grate (or below), under which (by which) there is a pipe with fuel burners built into it and a gaseous oxidizer supply unit, which is an air supply pipe.

In addition to burning hazardous biological objects in the known device, it is fundamentally possible to use it for burning low level radioactive biological objects (I group of solid radioactive waste (SRW) [4], because the degree of entrainment into the gas phase of Sr ⁹⁰ and Cs ¹³⁷ (the main quantitative component of all radionuclides present in solid radioactive waste) for Sr ⁹⁰ does not exceed 0.5%, and for Cs ¹³⁷ - 1.4-4% of their initial amount in SRW [5].

 The known device operates as follows.

 Immediately before loading, the hinged lid of the loading opening of the combustion chamber is opened and the bioobjects burned are placed on it. Then, the hinged lid of the loading opening of the combustion chamber is returned to its original position. In this case, the burned bioobjects are placed on the grate or hearth. Air is supplied to the combustion chamber through the gaseous oxidizer supply unit and fuel burners are started simultaneously with the air supply. The flue gases from the combustion chamber are removed through the flue gas openings, the flue gas line and discharged into the atmosphere through the gas discharge unit. The resulting ash from the burning of biological objects is collected in the combustion chamber under the grate or on the hearth.

The disadvantages of the known device are:
- limited scope due to the impossibility of its use for burning radioactive biological objects belonging to the II group of SRW [4];
- reduced productivity for one combustion cycle, due to the fact that the working volume of the combustion chamber is less than its full volume, due to the location of the grate or hearth inside the combustion chamber above its bottom;
- reduced coefficient of reduction in the volume of burned biological objects, due to the fact that the grate or under provide a gaseous oxidizer only to the outer surface of the burned biological objects;
- reduced reliability due to the possibility of stopping the device due to the cessation of the gaseous oxidizer entering the combustion chamber and / or the cessation of fuel combustion in the fuel burners, which may be caused by clogging with solid combustion products of bioobjects of the openings of the gaseous oxidizer supply unit and / or channels of the fuel burners. This drawback is due to the location of the gaseous oxidizer supply unit and fuel burners under the grate or hearth;
- reduced reliability, due to the possibility of "failure" of the flame in the fuel burners.

 The advantages of the claimed device are the expansion of its scope, increase the reduction ratio of the volume of burned biological objects, increase productivity in one cycle of combustion, as well as increase the reliability of the device.

 These advantages are provided due to the fact that the claimed device consists of a wall, a cover and a bottom of the combustion chamber located on supports in the casing of the combustion chamber consisting of walls and a bottom. In the cover of the combustion chamber there is a loading opening of the combustion chamber closed by a hinged lid, as well as a gas outlet, which is connected through a gas outlet to a gas outlet connected to a gas outlet with an exhaust device (exhaust fan), and a fine filter is located on the gas outlet.

 The casing of the combustion chamber is located in the support assembly, the walls and the bottom of the casing of the combustion chamber forming an air-intake duct-like channel with the walls and the bottom of the combustion chamber, which is a gaseous oxidizer supply unit, and a coarse filter is located inside the combustion chamber that covers its gas outlet.

 The bottom of the combustion chamber is a metal plate with parallel cylindrical channels and through slit-like channels tapering from the bottom up made in it and located parallel to it in parallel rows. In the through cylindrical channels there are also installed pointed pins located in parallel rows and protruding above the surface of the metal plate, in each of which an air supply channel is made having a lower inlet and upper outlet openings. The distances L between each two adjacent parallel rows of pointed pins are equal to each other. The distances between each two adjacent pointed pins in a row are also equal to each other. The distance L is (5 - 15) H, where H is the thickness of the metal plate. The height of the part of each pointed pin M protruding above the surface of the metal plate is at least 3H, and the height of the upper outlet openings of the air supply channel of each pointed pin K above the surface of the metal plate is at least 0.2M.

The implementation of through slit-like channels tapering from the bottom up prevents (by increasing the speed, when moving along them, entering the combustion chamber) the risk of clogging them with solid combustion products of biological objects, and the presence of pointed pins in a metal plate installed and made in this way increases the coefficient of volume reduction burned bioobjects due to:
- ensuring the supply of a gaseous oxidant to the entire surface of the burned bioobjects due to the creation of a gap between the bioobjects placed on the pointed pins and the surface of the metal plate;
- ensuring the supply of a gaseous oxidizing agent into biological objects through the air-supplying channels of the pointed pins, buried in biological objects under the influence of their weight.

 When L is less than 5H, the strength of the metal plate decreases, which during the operation of the device (under the influence of thermal and mechanical loads) can lead to its destruction. With L greater than 15H and M less than 3H, and also if the conditions for equal distances between each two adjacent parallel rows of pointed pins, as well as distances between each two adjacent pointed pins in a row, it is not possible to create a gap between biological objects placed on the pointed pins and the surface of the metal plate. When K is less than 0.2 M, the possibility of supplying air into biological objects through the air supply channels of the pointed pins is not achieved.

Distinctive features of the claimed device, ensuring the achievement of the above advantages, are:
- the presence of a fine filter located on the gas outlet between the gas outlet of the combustion chamber and the gas outlet;
- the presence of an exhaust device in the gas discharge unit, providing the movement of exhaust gases through the filters of rough and fine cleaning;
- the fact that the gaseous oxidizer supply unit is an air intake duct-like channel formed by the casing of the combustion chamber and the combustion chamber;
- the fact that inside the combustion chamber is additionally located a coarse filter that overlaps its gas outlet;
- the use as the bottom of the combustion chamber of a metal plate with parallel through rows of slit-like channels narrowing upwards and through cylindrical channels made in it and located parallel to it, in which parallel pins are arranged that are arranged in parallel rows, protruding above the surface of the metal plate, with air inlets channels and having lower inlet and upper outlet openings;
- the fact that the distances between each two adjacent parallel rows of pointed pins are equal to each other and make up (5 - 15) H;
- that the distances between each two adjacent pointed pins in a row are equal to each other;
- the fact that the height of the part of each pointed pin M protruding above the surface of the metal plate is at least 3H, and the height above the surface of the metal plate of the upper outlet openings of the air supply channel of each pointed pin K is at least 0.2 M.

 The inventive device is illustrated by the drawings shown in FIG. thirteen.

 In FIG. 1 shows a General view of the device.

 In FIG. 2 shows the bottom of the combustion chamber in a section along AA (side view).

 In FIG. 3 shows the bottom of the combustion chamber (top view).

 A mobile device for burning radioactive and hazardous biological objects contains a combustion chamber 1, a casing 2 of the combustion chamber, a gaseous oxidizer supply unit 3, supports 4, a support unit 5, a gas outlet 6, a fine filter 7, a gas discharge unit 8.

 The combustion chamber 1 contains walls 9, a cover 10, a loading opening 11, a hinged cover 12 of the loading opening, a bottom 13, a gas outlet 14, a coarse filter 15.

 The bottom 13 of the combustion chamber contains a metal plate 16, pointed pins 17, through slit-like channels 18 tapering from the bottom up, air supply channels 19 of the pointed pins, lower inlets 20 of the pointed pins, upper outlet openings 21 of the pointed pins.

 A mobile device for burning radioactive and dangerous biological objects works as follows.

 Immediately prior to loading, the hinge cover 12 of the loading opening of the combustion chamber is opened. Burning bioobjects are placed on the pointed pins 17 of the bottom of the combustion chamber together with powdered metallized fuel (PMT) and coke [6], after which the hinged cover 12 of the loading opening of the combustion chamber is closed, an exhaust device is turned on and the PMT and coke are remotely ignited. Air (gaseous oxidizing agent), passing through the gaseous oxidizer supply unit 3, enters under the bottom 13 of the combustion chamber, from where through the slit-like channels narrowing from the bottom upwards 18, as well as through the lower inlets 20 of the pointed pins, the air supply channels 19 of the pointed pins and the upper outlet openings 21 Pointed pins are fed to the entire outer surface, as well as inside the burned bioobjects. The resulting gaseous products of burning biological objects sequentially pass through the coarse filter 15, the gas outlet pipe 14, the gas exhaust pipe 6, the fine filter 7 and are discharged through the gas discharge unit 8 into the atmosphere. Solid products of burning biological objects are collected in the casing 2 of the combustion chamber under its bottom.

Tests have shown that:
- in the inventive device, it is possible to burn radioactive biological objects belonging to the II category of SRW, because the total specific activity of gaseous products of combustion does not exceed the maximum permissible level;
- the coefficient of reduction in the volume of burned biological objects, provided by the operation of the inventive device, is higher than the equivalent in the device of the closest analogue by an average of 20 - 25%;
- the inventive device has a higher productivity per combustion cycle due to the possibility of burning more bioobjects in its process compared to the closest analogue device, since the working volume of the combustion chamber increases (due to the use of a metal plate burning chamber as the bottom pointed pins and air ducts) to its full volume;
- the inventive device is more reliable in operation due to the use of a gaseous oxidizer supply unit as an unobtrusive solid burning of biological objects.

LITERATURE
1. US patent N 5339752 A, IPC ⁵ : F 23 G 1/00, NKI: 110-194, on. 08/23/94.

2. Copyright certificate of the USSR N 631749, IPC ² : F 23 G 1/00, op. 11/05/78, BI N 41 /
3. International application WO 92/20965, IPC ⁵ : F 23 G 1/00, 5/40, F 23 M 5/00, op. 11/26/92.

 4. I. A. Sobolev, L. M. Khomchik, “Disposal of radioactive waste at centralized sites”, Moscow, Energoatomizdat, 1983, p. 7.

 5. Ibid., Pp. 31 - 32.

6. RF patent N 2106706 C1, IPC ⁶ : G 21 F 9/32, F 23 G 7/00, op. 03/10/98, Bull. N 7.

Claims (1)

 A mobile device for burning radioactive and dangerous biological objects, including a gas discharge unit, a gaseous oxidizer supply unit located in the casing of the combustion chamber, a combustion chamber comprising a cover, walls, a bottom, a loading hole, a hinged cover of the loading hole and a gas outlet, and a gas outlet, connecting the gas outlet of the combustion chamber with a gas discharge unit, characterized in that the device further comprises a fine filter located on the gas outlet the line between the gas outlet of the combustion chamber and the gas discharge unit, the gas discharge unit further comprises an exhaust device, the gaseous oxidizer supply unit is an air intake duct formed by the casing of the combustion chamber and the combustion chamber, the combustion chamber further comprises a coarse filter located inside it so that overlaps its gas outlet, the bottom of the combustion chamber is a metal plate made in it and located across it in parallel rows of through slit-like channels tapering from bottom to top, as well as through cylindrical channels, in which pointed pins with air-supplying channels made in them and having lower inlet and upper outlet openings located in parallel rows are also installed, and the distances between each two adjacent parallel rows of pointed pins are equal to each other and make up (5-15) H, where H is the thickness of the metal plate, distance the relations between each two adjacent pins in a row are equal to each other, the height of the part of each pointed pin M protruding above the surface of the metal plate is at least 3H, and the height of the upper outlet openings of each pointed pin above the surface of the metal plate is at least 0.2 M.

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