RU2339099C1 - Station for combined utilisation of solid waste and sewage contaminated by radioactive components - Google Patents

Abstract

FIELD: physics, nuclear physics.

SUBSTANCE: invention concerns utilisation of organic-containing waste contaminated by radioactive components (overalls, filters, flush water etc.) obtained in technological processes. Station for combined utilisation of solid waste and sewage contaminated by radioactive components includes thermal reactor, cyclone furnace, catalytic afterburner, shell and tube heat exchanger, gas treatment system, and exhaust fan. Thermal reactor includes heating chamber with thermal destruction chamber positioned inside. Thermal destruction chamber features waste loading and coke ash content discharge devices. Cyclone furnace features burner. The station also includes gas distributor and horizontal evaporation pan. Gas distributor is positioned at the inlet of shell and tube heat exchanger. Evaporation pan bottom includes fumivorous channel system. Channels inlet is connected to gas distributor, while outlet is connected to gas treatment system inlet. Side walls of evaporation pan can feature overflow slits maintaining certain fluid level in the pan to meet requirements of nuclear safety.

EFFECT: combined utilisation of solid waste and sewage containing radioactive components without the use of additional thermal energy sources, and meeting nuclear safety requirements.

2 cl, 2 dwg

Description

The invention relates to the field of disposal of organo-waste, contaminated with radioactive components (clothing, filters, flushing water, etc.) generated during technological processes.

The installation for the joint utilization of solid and liquid wastes contaminated with radioactive components, containing a thermoreactor, a cyclone furnace, a catalytic afterburner, a shell-and-tube heat exchanger, a gas purification system and a smoke exhauster, is equipped with a gas distributor located at the inlet to the shell-and-tube heat exchanger and a horizontal evaporation bath, the bottom of which contains a smoke system channels, the entrance to which is connected to the gas distributor, and the output to the entrance to the gas treatment system. There are overflow slots in the side walls of the evaporation bath, providing a level of the liquid in it that meets the requirements of nuclear safety.

A known method of processing liquid radioactive waste, which consists in concentrating the waste by evaporation, by supplying liquid waste to glycerin (see patent RU 22831, 04/27/2002).

The disadvantage of this method is that the process requires a large amount of heat, as a result of which the installation for its implementation has large heat-exchange surfaces and energy consumption.

The disadvantage of the installation is the inability to dispose of solid waste in it.

Closest to the claimed utility model for the design of the main equipment, the principle of operation and the achieved result is a device for the disposal of solid waste containing a thermal decomposition chamber with a loading device, a vertical cyclone furnace with an afterburner equipped with a burner and an air supply channel in the upper part, a catalytic afterburner, heat exchanger, dust cleaning system and smoke exhaust. The loading device and means for unloading the coke ash dust and sludge residue are equipped with glove boxes under vacuum, all air intake channels of the installation are equipped with filters with check valves, which exclude the possibility of radioactive components entering the atmosphere during an abnormal increase in pressure (cotton), the gas purification system is equipped with means for collecting and preparation of the collected sludge for re-pyrolysis, and the internal volumes and relative positions of the plant elements exclude the possibility of accumulation the critical mass of radioactive components (see patent RU 42289, 11.27.2004).

The disadvantage of this device is the ability to dispose of liquid waste in it only in small quantities in the form of their addition to the bulk of the utilized solid waste, since the thermal decomposition chamber of this device is not suitable for the accumulation and subsequent evaporation of a large mass of liquid.

Another disadvantage of the device is that in order to ensure a technological process that requires lowering the temperature of the flue gases at the inlet of the dust cleaning system to 150-200 ° C, it is necessary to constantly remove the heat generated during waste disposal in the heat exchanger, even if its subsequent useful use is impossible.

The aim of this invention is the provision of joint utilization of solid and liquid wastes contaminated with radioactive components, without the use of external thermal energy.

This goal is achieved due to the fact that the installation for the joint utilization of solid and liquid wastes contaminated with radioactive components, containing a thermoreactor, a cyclone furnace, a catalytic afterburner, a shell-and-tube heat exchanger, a gas purification system and a smoke exhauster, is equipped with a gas distributor located at the entrance to the shell-and-tube heat exchanger, and horizontal an evaporation bath, the bottom of which contains a system of smoke channels, the entrance to which is connected to the gas distributor, and the exit to the entrance to the gas purification system and. There are overflow slots in the side walls of the evaporation bath, providing a level of the liquid in it that meets the requirements of nuclear safety.

Thermal decomposition (pyrolysis) of waste in a thermoreactor in an oxygen-free atmosphere allows the bulk of the organic matter contained in solid waste to be converted to a gaseous state - a gas-vapor mixture (ASG), leaving the bulk of the radioactive components in the coke ash residue. The gas-vapor mixture is then sent to the cyclone furnace, and the flue gases generated after its combustion, which have a high temperature and significant thermal potential, are used in the evaporation bath to dispose of liquid waste. Thus, there is no need to use an additional external source of thermal energy necessary for the evaporation of moisture.

The supply of a shell-and-tube heat exchanger with a gas distributor located at its inlet allows flue gases to be sent to the evaporation bath in an amount necessary for the disposal of liquid waste contained in it. At the same time, in the absence of the need for liquid waste disposal, the gas distributor allows you to turn off the evaporation bath and direct the flue gas stream directly to the heat exchanger.

Providing the bath with a system of smoke channels mounted in its bottom allows you to evenly distribute the heat flux throughout the entire volume of the liquid, which contributes to its more intense evaporation.

The presence of overflow slits in the side walls of the evaporation bath provides nuclear safety conditions, since it eliminates the possibility of the formation and accumulation of a critical mass of radioactive products in the bath.

Figure 1 and 2 presents the installation diagram and longitudinal and transverse sections of the evaporation bath.

The installation comprises a thermoreactor 1, consisting of a heating chamber 2 with a thermal decomposition chamber 3 located therein, equipped with means for loading waste 4 and unloading the coke residue 5; cyclone furnace 6 equipped with a burner 7; catalytic afterburner 8; shell-and-tube heat exchanger 9 with a gas distributor 12; an evaporation bath 13 with a system of smoke channels 14 with inlet and outlet of flue gases 15 and 16; gas cleaning system 10 and exhaust fan 11.

To ensure that the liquid level in the evaporation bath meets the requirements of nuclear safety, there are overflow slots 17 in its side walls.

Disposal of waste is carried out as follows.

Waste is placed in a loading device, by means of which it is transferred to a thermal decomposition chamber (CTE), which is a metal retort heated during the period of heating by flue gases obtained from burning external fuel in a burner. The waste is heated to a final temperature of 650-700 ° C without oxygen, and during heating they decompose (pyrolysis), resulting in approximately 60-70% of gaseous combustible gases and 30-40% of coke-ash residue. The gaseous products of pyrolysis due to the draft of the smoke exhauster enter the furnace, where they are mixed with the required amount of air, and they are burned. The resulting flue gases due to the draft of the exhaust fan are successively sucked through the catalytic afterburner cartridge, where the residual organic compounds are oxidized, and enter the gas distributor, through which they are metered into the evaporation bath and shell-and-tube heat exchanger. The ratio of the gas flows passing through these devices depends on the ratio and thermophysical properties of solid and liquid wastes disposed at a given time.

Passing through a system of smoke channels installed in the bottom of the evaporation bath, flue gases having a high temperature and significant thermal potential give off heat to heat and evaporate the liquid placed in the bath and then enter the gas purification system.

The rest of the flue gas is sent to a shell-and-tube heat exchanger, where it is cooled by a flowing heat carrier.

In the gas purification system, the flue gas is first cleaned of dust in a “dry” cyclone and then washed with liquid in a “wet” scrubber. The cleaned flue gas enters the smoke exhauster, with the help of which it is emitted into the atmosphere.

Thus, the combination of these essential features makes it possible to simultaneously utilize solid and liquid wastes containing radioactive components without the use of additional sources of thermal energy and in compliance with nuclear safety requirements.

Claims (2)

1. Installation for the joint utilization of solid and liquid wastes contaminated with radioactive components, comprising a thermoreactor equipped with a heating chamber with a thermal decomposition chamber provided with devices for loading waste and unloading coke residue, a cyclone furnace equipped with a burner, a catalytic afterburner, a shell-and-tube heat exchanger , gas treatment system and smoke exhaust, characterized in that the installation is equipped with a gas distributor located at the entrance to the shell-and-tube heat exchange ravennik and a horizontal evaporation bath, the bottom of which contains a system of smoke channels, the entrance to which is connected to the gas distributor, and the exit to the entrance to the gas treatment system. 2. Installation according to claim 1, characterized in that there are overflow slots in the side walls of the evaporation bath, which ensure the level of liquid in it that meets the requirements of nuclear safety.

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