JPH0413004B2 - - Google Patents

Abstract

1. Method for the treatment of gaseous effluents in order to remove the impurities therefrom, the said gaseous effluents escaping from a high temperature reactor (1), and a material in granular form (23) being supplied to the reactor, the said method being characterised in that - the material in granular form is supplied through a downwardly inclined pipe (13), provided with a conveyor (17) whereof the speed is controlled in order to supply the reactor in a manner sufficient to satisfy its requirements ; - countercurrently a stream of gaseous effluents is made to rise in said pipe (13) through the material in granular form (23) and the supply rate of the material in granular form and the speed of the gaseous effluents are controlled independently such that the particles present in the gaseous effluents are substantially all arrested by the material in granular form and returned to the high temperature reactor and the purified gaseous effluents are allowed to leave the reactor.

Description

BACKGROUND OF THE INVENTION a. Field of the Invention The present invention relates to the purification of effluent gases. More particularly, the present invention is the treatment of gaseous effluents produced in or emerging from high temperature reactors to remove impurities from the effluents. More particularly, the present invention provides a method for filtering particles from a gas;
It relates to an apparatus for feeding material to be treated into a reactor while condensing volatile products and returning it to the reactor.

b. Description of the Prior Art It is known that certain materials are heated and/or treated in reactors or furnaces for various reasons. Gases are often generated or used, for example, in furnaces used to process materials such as minerals, scrap, radioactive waste, chlorinated polymers, and the like. These gases include dust and condensable products. It is necessary to recover dust and condensable products because of their economic value and to limit the extent of pollution if they are allowed to escape into the atmosphere. External equipment such as filters, separators, condensers, etc. are currently used to treat the gas and separate dust and condensable products.

Volatile substances such as cesium oxide and ruthenium oxide are known to be dangerous if left to escape with gases after nuclear waste disposal and before radioactive materials are buried.

The purpose of the invention is to successfully condense radioactive materials and prevent dust arising from the disposal of nuclear waste.

Another object of the invention is to provide a device making it possible to prevent dust, droplets, hazardous products and other undesirable substances from escaping into the atmosphere.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides an apparatus for treating a gaseous effluent to remove condensable impurities and particulate impurities from the gaseous effluent, the apparatus for treating the gaseous effluent comprising: a high-temperature reactor having a product outlet at the bottom in which is generated; at least one inlet for feeding material to be treated into said reactor; and for heating the contents of said reactor. a duct connected to the reactor for supplying particulate material into the reactor that interacts with the material to be treated, an inlet for the particulate material and an outlet for the treated gas. a chamber in communication with the duct; a screw conveyor disposed within the duct; and a screw conveyor configured to supply the reactor with granular material in an amount sufficient to meet the requirements of the reactor. a control device for adjusting the speed of the screw conveyor, the screw conveyor being provided with a particular pitch and diameter to adjust the speed of the gaseous effluent through the particulate material. and thereby causing substantially all condensable impurities and particulate impurities within the gaseous effluent to be trapped in the particulate material as the gaseous effluent moves through the duct. An apparatus for treating gaseous effluents is provided.

The present invention will be explained below with reference to the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The gaseous effluent treatment apparatus shown in the drawings comprises:
It comprises a reactor 1 which can be used, for example, to provide a solution between nuclear waste and sand. The reactor can be heated by any device known to those skilled in the art, such as by the use of electrodes (not shown). This heating device is indicated schematically by arrow 3. Materials intended to be treated in the reactor 1, such as sludge, chlorinated polymers, radioactive materials, etc., are introduced into the reactor via the inlet 5. This material is introduced into the reactor 1 in the direction indicated by arrow 7.

At the bottom of the reactor there is a product outlet 9 which is used to remove the processed product in the manner described below.
The top of the reactor is isolated from the outside world by a closure 11. The duct 13 is the closed body 11
As mounted above and shown, the closure 11 communicates with a chamber 15 described below.

Throughout the length of the duct 13 there is a screw conveyor 17, which
It is connected via a shaft 19 to a device (not shown) for enabling the screw conveyor to rotate in the direction indicated by arrow 21. Of course, any device for conveying feed particles through the duct may be used without departing from the spirit of the invention. Particulate material 23 intended to be interacted with nuclear waste enters chamber 15 from inlet 25.
and is allowed to flow into chamber 15 in the direction indicated by arrow 27. Gases escaping from the processing device exit through outlet 29.

In some cases, it is preferred to introduce the hazard directly into the reactor via the second inlet, especially when the material is intended to be processed. In normal operation of the processing device, it is inserted into the reactor 1 through the inlet 5. In the case of radioactive materials, the intention is to form a glassy mass of radioactive material to prevent the material from being leached out. For this purpose, after heating the reactor, sand is introduced through the inlet 25 and the screw conveyor 17
As a result of the rotation of , it is possible to go down in the duct 13 in a controlled downward movement. The speed of the conveyor is adjusted such that the feed rate of particulate material into the reactor is adapted to meet the feed requirements of the reactor. By heating the mixture of sand and radioactive material, gaseous products gradually emerge from the bath 33 and increase the pressure in the reactor, which pressure rides along the blades of the screw conveyor 17. At the same time, the flow in the opposite direction to the sand passing through the duct 13 pushes the gas away and moves it upward.

Reactive products, condensable substances and particulate matter or dust are captured by the descending sand and returned to the bath 33. The gas escaping into chamber 15 is allowed to exit into the atmosphere in a relatively pure state.

This processing equipment has obvious uses for the solidification of nuclear waste, and also for the incineration of hazardous waste, in metallurgical furnaces, in furnaces used for recovering special alloys. It can also be used in furnaces used for the production of glass and ceramics. Of course, other uses can be envisaged.

For example, in the case of nuclear waste, this treatment device can be used with sand to condense volatile materials and stop dust generation. If the waste is toxic and the toxic waste is incinerated, sand and coke can be used to stop the dust and droplets. Sand and reaction products can be used to prevent hazardous products.
Finally, the treatment device according to the invention can be used to prevent dust from escaping into the atmosphere within the metallurgical furnace.

More specifically, the loss of volatile materials such as cesium oxide and ruthenium oxide when nuclear waste is being processed is controlled by the rate of evaporation from the surface of the liquid bath and the rate of dissolution within the liquid. be done.
The fact that volatilized or gas-borne waste is returned to the bath significantly reduces losses. This is because only a small portion of the material returned to the bath is volatilized again or transported back by the glass.

In this application, waste can be fed through inlet 5 or 31 in the form of liquid, solid or mud.

For the incineration of toxic wastes, it is possible to use a continuous feed of coke or sand to capture solid particles and droplets that would not be destroyed in the furnace. By controlling the temperature of the particulate material before it reaches the reactor, the waste can be combusted or returned to the reactor for further processing.

In some applications, it may be advantageous to select particulate materials that can react with gaseous chemical products to produce reaction products that are returned to the reactor.

In metallurgy, the main use is to prevent most of the dust from reaching the outside atmosphere.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a gaseous effluent treatment apparatus according to the invention. 1... Reactor, 5... Inlet, 31... Second inlet, 25... Inlet, 29... Gas outlet, 13...
Duct, 17...screw conveyor.

Claims (1)

[Claims] 1. An apparatus for treating a gaseous effluent to remove condensable impurities and particulate impurities from the gaseous effluent, the apparatus for treating a gaseous effluent comprising a lower part in which the gaseous effluent is generated. a high-temperature reactor 1 with a product outlet 9 at and at least one inlet 5, 31 for feeding the material to be treated into said reactor and a device 3 for heating the contents of said reactor. and a duct 13 connected to the reactor for feeding into the reactor particulate material 23 that interacts with the material to be treated;
a chamber 1 having an inlet 25 for the granular material and an outlet 29 for the treated gas and communicating with the duct;
5, a screw conveyor 17 disposed within the duct, the speed of the screw conveyor being adjusted to supply the reactor with a sufficient amount of granular material to meet the requirements of the reactor; a control device for controlling the gaseous effluent, said screw conveyor being given a specific pitch and diameter to adjust the velocity of the gaseous effluent through the particulate material; Processing a gaseous effluent, wherein substantially all condensable impurities and particulate impurities within the gaseous effluent are trapped in the particulate material as the effluent moves through the duct. device to do.