RU2232943C1 - Method for reclamation of chemical weapon, contaminated containers and grounds - Google Patents

Abstract

FIELD: environmental protection, in particular, methods for reclamation of chemical weapon of all types, contaminated containers (used shells inclusive) and grounds.

SUBSTANCE: the method consists in the following. The waste to be reclaimed is placed in a pyrolysis block, where it is heated to 800 to 950C. The gaseous products produced thereby are fed to a plasmochemical unit (plasmatron) for further destruction through a filter filled with titanium sponge heated to 800C. The titanium filter is aimed to prevent formation of supertoxicants in the titanium filter.

EFFECT: expanded field of application, simplified process and reduced cost.

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Description

The invention relates to environmental protection, and in particular to methods for the disposal of all types of chemical weapons, contaminated containers (including used shells) and soils.

There is a method of destruction of organic substances without oxygen - pyrolysis [1].

The disadvantage of this method is that a large number of secondary gaseous supertoxicants are formed during pyrolysis and its implementation requires a complex system of environmental treatment of exhaust gases.

Also known is a method of plasma chemical disposal of toxic organic waste, which consists in high-temperature destruction of waste in a plasma torch, followed by exposure at high temperature in a plasma chemical reactor until they are completely decomposed [2].

One of the significant drawbacks of the method of plasmachemical utilization is the lack of regulation of the process of binding of the reaction atoms of the original supertoxicant molecule. In addition, plasmochemical utilization does not exclude the formation of secondary supertoxicants during plasma cooling.

Closest to the proposed method is a plasma-chemical disposal of organophosphorus toxic substances and lewisite, which consists in heating and decomposing them in a plasmatron and holding in a reactor. Simultaneously with the utilized product, titanium is supplied to the mixing chamber of the plasma torch. Additionally, titanium is fed to the reactor. The process of plasma-chemical decomposition is carried out in an environment inert with respect to titanium at a temperature of 500-6000 ° C. The supply of powdered titanium to the plasma-chemical reactor makes it possible to irreversibly separate the molecule of the initial substance and thereby actually destroy chemical weapons [3].

However, in the known method, the problem of eliminating excess carbon from the molecular system with which the molecule of the starting material is saturated is not sufficiently efficiently solved. This is due to the fact that carbon binding requires a large amount of titanium, which leads to a sharp increase in the cost of plasma chemical chemical weapons disposal technology (organophosphorus toxic substances). The disadvantage of this method is the difficulty of supplying powdered titanium through a dispenser (the complexity of the method). In addition, the known method does not solve the problem of disposal of containers from chemical weapons and contaminated soils.

The features of the prototype method, which are common with the features of the proposed method, is heating and destruction of the utilized substance in the plasma chemical unit to a temperature of 950-5000 ° C.

The objective of the invention is the expansion of the scope of the method, its simplification and cost reduction.

The problem is solved due to the fact that in the known method for the disposal of chemical weapons, contaminated containers and soils, which consists in heating and destruction of the utilized substance in the plasma chemical unit to a temperature of 950-5000 ° C, additionally before that, the utilized substance is heated in the pyrolysis unit without access oxygen to a temperature of 800-950 ° C. Gaseous products formed in the pyrolysis unit are passed through a filter filled with a titanium sponge heated to a temperature of 800 ° C and sent to a plasma chemical unit for further destruction.

Signs that distinguish the claimed technical solution from the solution of the prototype are the additional heating of the utilized substance in the pyrolysis unit without oxygen access to a temperature of 800-950 ° C, the supply of gaseous products formed in the pyrolysis unit to the plasma chemical unit for their further destruction, and the cleaning of the resulting pyrolysis unit gases before feeding them to the plasma chemical unit using a filter filled with a titanium sponge heated to a temperature of 800 ° C.

The method is as follows.

Recycled waste is placed in the pyrolysis unit, where it is heated without oxygen to a temperature of 800-950 ° C. The heating time of the pyrolysis unit is 5 hours, and with cooling and changing the batch of loading - 12 hours. When the waste is heated, all volatile components turn into a gaseous state, while various toxic gaseous products are formed in the pyrolysis unit, which are complex in structure and highly toxic. To break bonds in the molecules of these products (i.e., for further degradation), the gas formed in the pyrolysis unit is supplied to the plasma chemical unit (plasmatron). In the plasma chemical unit, the heating of gaseous products to a temperature of 950-5000 ° C continues, and at the same time, the destruction process proceeds. Various products (air, nitrogen, argon, water vapor) are supplied there (to the plasma torch) to destroy toxic gases and produce environmentally friendly products. For example, when it enters the plasma chemical unit from the methane pyrolysis unit, oxygen is supplied to the plasma chemical unit. In this case, water and carbon dioxide are formed.

Volatile components formed in the pyrolysis unit enter the plasma chemical unit through a filter filled with a titanium sponge heated to 800 ° C. A titanium sponge is a semi-finished product of titanium production and is much cheaper than the titanium powder used in the prototype method. At a temperature of 500-800 ° C, titanium actively absorbs some gases (namely fluorine and oxygen). The task of the titanium filter is to prevent the entry of fluorine and oxygen atoms formed after pyrolysis, together with the gas medium, into the plasma chemical unit. This is done in order to exclude the formation of secondary supertoxicants in the plasma chemical unit.

After the plasma chemical unit, the hot gases are cooled in a heat exchanger and purified from acid gases by water in a scrubber. The acids formed in this case are neutralized by known methods. And the resulting gaseous hydrocarbons are sent for afterburning.

A significant part of the carbon in the form of coke, which was part of the molecules (the so-called excess carbon), remains in the pyrolysis unit during the disposal of chemical weapons. The resulting coke is an environmentally friendly product and can be disposed of as a substance of the fourth hazard class, and its burning in the open air is also allowed. When disposing of contaminated containers and soil, the neutralized container from the pyrolysis unit is sent for re-melting, and the neutralized soil is sent to solid domestic waste landfills.

When lewisite is utilized, arsenic is released in pure form due to the binding of chlorine atoms by titanium. After the plasma-chemical block in the scrubber, the hydrocarbon products are separated from arsenic and fed to the afterburner. The condensed phase formed after the plasma-chemical block, with a predominant arsenic content, is subjected to sublimation at a temperature of 615 ° C with the formation of spectrally pure arsenic as a commercial product.

An example of a specific implementation of the method.

The method was carried out on an EDP-209 plasmatron (designed by the Novosibirsk Institute of Thermophysics, Russian Academy of Sciences. It is possible to use plasmatrons of the NII HIMMASH). The plasma torch worked on argon (a neutral gas with respect to titanium), the argon flow rate was from 0.01 to 0.1 g / s (determined by differential thermal analysis by the intensity of the vaporized initial model substance). The recyclable substance - containers contaminated with chemical weapons (shells, iron barrels, for example) - were placed in a pyrolysis unit, where they were heated to a temperature of 950 ° С. In the pyrolysis unit, carbon was formed in the form of coke 23 mol.% And 77% of gaseous products. Carbon (coke) is an element of the natural environment and does not pose a hazard. The resulting gaseous products (such as, for example, hydrogen chloride, methane, phosphine, phosphoric acid, combustible gases, etc.), through a filter filled with a titanium sponge heated to 800 ° C, entered the plasma chemical unit for heating and oxidation (for further destruction ) The heating temperature in the plasma chemical unit — in the mixing chamber — was 5000 ° C. The whole process — pyrolysis and plasma-chemical destruction — proceeded for 8 hours. Air was supplied to the plasma chemical unit, while the gaseous organophosphorus products were oxidized to carbon dioxide and phosphoric acid, as well as the neutralization of molecular chlorine with sodium carbonate. In the pyrolysis block, neutralized iron containers (shells) remained, contaminated with soot, which can be sent for re-melting.

Similarly, the process of disposal of contaminated with chemical weapons (eg sarin) soil can be implemented.

Sources of information

1. Belkov V.M. Methods, technologies and the concept of utilization of carbon-containing industrial and solid wastes. Chemical industry. - 2000. - No. 11, p. 8.

2. Vaysman, Ya. and other Plasma-chemical disposal of toxic organic waste. Ecology and industry. - 1998. - No. 10, p. 15-17.

3. Khalturin V.G. and others. A method of plasma-chemical disposal of organophosphorus toxic substances and lewisite. Patent No. 2169884 dated 06/27/01.

Claims (1)

The method of disposal of chemical weapons, contaminated containers and soils, which consists in heating and destruction of the utilized substance in the plasma chemical unit to a temperature of 950-5000 ° C, characterized in that, in addition, before that, the utilized substance is heated to a temperature of 800-950 ° C in the pyrolysis unit without oxygen access, and gaseous products formed in the pyrolysis unit are passed through a filter filled with a titanium sponge heated to a temperature of 800 ° C, and sent to a plasma chemical unit for further heating and destruction tion.