RU2386898C2 - Device for combustion of liquid organic radioactive waste - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: device for combustion of liquid organic radioactive waste includes a housing, treatment assembly of liquid organic radioactive waste and primary air, combustion chamber and catalytic probe. Treatment assembly of liquid waste and primary air includes an atomiser installed at the housing bottom coaxially to combustion chamber and heat exchanger located between the housing wall and combustion chamber. In lower housing part there located is helical channel for supply of secondary air with tangential outlets made in the housing. Lower edge of combustion chamber is located between lower and upper walls of helical channel, and aftercombustion chamber is located between combustion chamber and catalytic probe.

EFFECT: increasing combustion efficiency, reducing power consumption and simplifying the device design on condition that industrial nuclear safety requirements are met.

3 dwg

Description

The invention relates to a device for burning liquid organic radioactive waste resulting from the operation of various mechanisms in radiochemical production, for example, contaminated vacuum and other oils.

A known installation for burning hazardous waste and fluids, having an elongated cylindrical combustion chamber, a pipeline for injecting waste into the combustion chamber and an air supply device designed to supply more air flow to the combustion chamber. One or more nozzles are introduced into the combustion chamber, creating a stoichiometric concentration of fuel ignited by an electric ignition device supplied with fuel (EPO Application No. 0304879, published 01.03.1989). A disadvantage of the known device is the need to use additional fuel for an electric ignition device.

The closest in technical essence to the invention is a device for the treatment of liquid radioactive waste, comprising a housing, a combustion chamber with a heater, a catalytic nozzle, a unit for the preparation of liquid waste and primary air, which is a vaporization cell surrounded by a heater, into which a cylindrical mixer with holes in the side is inserted the wall. A pipe for supplying processed waste and a pipe supplying air sparging through the waste are introduced inside the mixer. (Japanese Application No. 61-27720, publ. 06/26/1986).

The disadvantages of this device are as follows.

1. Technological inefficiency in the production of liquid radioactive waste vapors by air sparging of treated waste.

2. Economic inefficiency due to the presence of two heaters: an evaporator cell heater and a combustion chamber heater.

3. The complexity of the design due to the presence of separate units of evaporation and combustion of a mixture of waste and air.

4. The absence of a afterburner leads to inefficiency of waste gas utilization and the likelihood of soot formation and its accumulation on the catalyst surface.

The problem to which the invention is directed is to develop a device design that provides increased combustion efficiency due to the most complete combustion of liquid organic radioactive waste, reduced energy consumption and simplified device design, subject to the requirements of industrial nuclear safety.

To solve this problem, a device for burning liquid organic radioactive waste is proposed, comprising a housing, a unit for preparing liquid organic radioactive waste and primary air, a combustion chamber, a catalytic nozzle. Moreover, the unit for the preparation of waste and primary air includes a nozzle installed in the bottom of the housing coaxially to the combustion chamber and a heat exchanger located between the wall of the housing and the combustion chamber. In the lower part of the housing there is a cochlear channel for supplying secondary air with tangential exits in the housing, while the lower end of the combustion chamber is located in the zone between the lower and upper boundaries of the cochlear channel, and the afterburner is located between the combustion chamber and the catalytic nozzle.

Figure 1 shows a longitudinal section of a device for burning liquid organic radioactive waste, figure 2 is a cross section aa in figure 1, figure 3 is a longitudinal section bb in figure 1.

The device comprises a cylindrical housing 1 (see FIG. 1) with a heat-insulating casing 2 and a heat-insulated bottom 3. In the lower part of the housing 1 there is a cochlear channel 4 with a pipe 5 for air inlet and tangential outputs 6 (see FIG. 2). In the housing 1 (see FIG. 1), a combustion chamber 8 consisting of open electric heating spirals 9, an insulator 10 and current leads 11 (see FIG. 3) is coaxially mounted on the racks 7 thereof. The lower end 12 (see figure 1) of the combustion chamber 8 is located between the upper 13 and lower 14 borders of the cochlear channel 4. The unit for preparing liquid organic radioactive waste (LRW) and primary air includes an external centrifugal mixing nozzle 15 and a heat exchanger made in the form of coils 16 and 17. The nozzle 15 is installed in the bottom 3 coaxially to the housing 1. The coil 16 is equipped with a nozzle 18 connected to the metering pump ЖОРО (not shown), and a nozzle 19 connected to the nozzle 20 of the nozzle 15. The coil 17 is equipped with a nozzle 21 connected toan compressor (not shown) and a nozzle 22 connected to the nozzle 23 nozzle 15. The heat exchanger is located between the wall of the housing 1 and the combustion chamber 8. Above the combustion chamber are a afterburner 24 and a catalytic nozzle 25. The nozzle 26 in the upper part of the housing is designed to exit gaseous combustion products, and the pipe 27 together with the explosive membrane 28 serves to relieve pressure in emergency situations. To monitor the operation of the device installed photosensor 29 and the necessary temperature sensors (not shown).

A device for burning ZhORO works as follows.

By means of an electric heating coil 9, the combustion chamber 8 is heated to the flash point of the utilized LRW. Through the nozzle 18, LFER is supplied with a given flow rate, and through the nozzle 21, primary air is supplied in an amount sufficient to spray waste through the nozzle 15. Passing through the coils 16 and 17, the LUMB and the air are heated from the outer surface of the combustion chamber 8 due to convective heat transfer, while in ZhORO viscosity decreases. Mixing LRWF of low viscosity with hot air creates the most favorable conditions for finely dispersed LRWR through nozzle 1 5 and partial evaporation and feeding it into the combustion chamber 8, where, due to the high temperature of the electric heating coil 9, an outbreak of a droplet-air mixture occurs. The flame is monitored by means of a photosensor 29. LRW combustion without soot formation occurs with a stoichiometric excess of air, therefore secondary air is additionally supplied to the housing through the nozzle 5 and tangential outputs 6. Secondary air enters the housing 1, rising in a spiral along the walls. In this case, the secondary air stream does not bring down the torch of the droplet-air mixture from the nozzle 15. A part of the incoming secondary air is ejected by the mixture flow from the nozzle 15 into the combustion chamber 8, which further increases the degree of combustion of the LRW. The rest of the secondary air passes between the wall of the housing 1 and the outer surface of the combustion chamber 8. This swirling stream of secondary air is heated, providing uniform heating of the coils 16 and 17, preventing them from overheating from the side of the combustion chamber 8. In the afterburner 24, the heated secondary air is mixed with incandescent stream from the combustion chamber 8. In the incandescent stream may contain particles of soot that are completely burned in the afterburner 24 with an additional excess of oxygen from a stream of secondary air. Next, the generated gases pass through the layer of the catalytic nozzle 25. Harmful impurities are oxidized to carbon dioxide and water and exit the housing through the nozzle 26 for purification from radionuclides.

The design of the proposed device allows more complete burning of LRW due to their intensive atomization by the nozzle and partial evaporation in the primary air stream and ensures guaranteed ignition of the resulting finely divided droplet-air mixture without the use of additional fuel. The presence of a afterburner ensures the burning of LRW without the formation of soot.

The proposed constructive solution for the LRW and primary air preparation unit using a single heater for both heating the LRW and primary air and for burning the air-drop mixture makes it possible to reduce energy consumption and simplify the design of the device, provided that the requirements of industrial nuclear safety are met.

Claims (1)

A device for burning liquid organic radioactive waste, comprising a housing, a unit for preparing liquid organic radioactive waste and primary air, a combustion chamber and a catalytic nozzle, characterized in that the unit for preparing liquid waste and primary air includes a nozzle and a heat exchanger installed in the bottom of the housing coaxially to the combustion chamber, located between the wall of the housing and the combustion chamber, in the lower part of the housing there is a cochlear channel for supplying secondary air with tangential passages in the housing, the lower end of the combustion chamber is located between the lower and upper walls ulitkoobraznogo channel and dozhigatelnaya chamber located between the combustion chamber and a catalyst packed.

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