EA012509B1 - Method for producing a fumigation gas (variants), device (variants) and composition (variants) for carrying out said method and fumigation method - Google Patents

Abstract

The invention is directed at fighting pests in food products. The inventive device for producing a fumigation gas in the form of a phosphine and carbon dioxide mixture is embodied in the form of a unit consisting of two chambers, wherein the first chamber is used for storing a mixture of a metal phosphide, carbon dioxide-producing substance and a substance inhibiting the chemical activity thereof and the second chamber is used for storing a water-acid mixture. Said device comprises a device for pressing the lid of the first chamber to the surface of the metal phosphide-containing mixture and a device which displaces the lid with respect to said surface and is provided with at least one opening for connecting the chambers to each other. The inventive method for producing a fumigation gas in the form of a phosphine and carbon dioxide mixture consists in placing the mixture of the metal phosphide, a substance producing carbon dioxide by a chemical endothermic process and a substance inhibiting the chemical activity thereof in a sealed shell contacting the mixture at all points of the surface thereof and, just prior to producing the fumigation gas, in forming a free volume which is arranged between the mixture and the shell and to which the water-acid mixture is supplied. Said invention makes it possible to increase the safety of the device storage and operation, to increase the life service thereof, to reduce the fumigation gas consumption and to improve the efficiency.

Description

The invention is intended for the destruction of pests in food products, mainly in grain, tobacco, quarantine objects, as well as containers, vehicles and premises intended for their processing, storage or long-term transportation.

State of the art

The destruction of food pests during their storage and lengthy transport remains a serious problem. When solving it, the main attention is paid to the following main points: the complexity of fumigation work, including waste collection and disposal, fire and explosion safety of fumigation, environmental safety (harmlessness of fumigation products and waste from its use).

One of the most important factors is the effectiveness of fumigation work, depending on the method of their implementation and the fumigation agent used.

Of the known fumigation products: chloropicrin, metal chloride, methyl bromide, preparations that produce phosphine, the fumigant gas containing phosphine is of most interest to consumers.

The most popular means of forming a fumigant gas with phosphine are tablets, plates, and pellets (German application No. 3047373, MKI 01B 25/06 - 1982; prospectus of the company Ge ^ ex 6MBN, Vip6e5geri1k, Esisyap. 1985).

Their disadvantages are the following:

fumigant gas production and its effectiveness depends on environmental conditions: in the first case, on humidity, in the second, on temperature;

the rate of generation of the fumigant gas cannot be high, since the transfer of moisture from the environment to the surface of the tablet is ensured by natural mass transfer and non-condensed moisture comes into contact with the tablet;

in case of accidental ingress of a large amount of moisture on the tablet, overheating and explosive situations are possible;

for fumigation work requires laborious piecewise distribution of tablets throughout the volume of the processed object;

incomplete decomposition of tablets (a residue of 2% is allowed) worsens the environmental performance of the processed products and creates the prerequisites for a fire and explosion hazard during the collection, packaging, transportation and disposal of residual decomposition products of tablets;

It is mandatory to carry out a laborious operation to collect and dispose of the products for processing tablets - pulverized aluminum hydroxide (or magnesium), etc.

Currently, the most effective in comparison with tablets and their analogues are devices in which a fumigant gas is produced by forcing a moistened diluent gas through a layer of metal phosphide.

The disadvantage of such solutions is their complexity and high energy consumption, due to the need to pump gas preliminarily prepared in a special way (humidification, heating) through the device.

In addition, an important problem is the creation and maintenance of the fumigation concentration in the fumigation facility, whether it is a silo, hold, warehouse or grain processing plant, for a period of time sufficient to accumulate an effective dose of the toxic effect of the fumigant gas on insect pests.

It should be noted that it is especially difficult to create an effective concentration field in layers of food products of large thickness, for example, in silos, since multipoint injection of a fumigant gas throughout the volume is impossible.

Closest to the claimed method of generating a fumigant gas, device and composition for its implementation and methods of fumigation is the application of the Russian Federation No. 98108921 IPC A 23 3/3409.

The method provides the production of a fumigant gas in the form of a mixture of phosphine with carbon dioxide and involves the use of metal phosphide, water, a binder, an acid and a substance emitting carbon dioxide during the chemical endothermic process, wherein the metal phosphide, a binder and a substance emitting carbon dioxide gas is pre-mixed and a mixture of acid and water is added to the resulting mixture to simultaneously produce carbon dioxide and compensate for the heat generated during phosphine production t chemical endothermic process of carbon dioxide formation.

A device for generating a fumigant gas is a reactor consisting of at least one block of two chambers communicating via a shutter element, one of which is designed to accommodate a mixture of metal phosphide, a substance that forms carbon dioxide during the chemical endothermic process, and a binder, and the second is for an acid solution, while the outlet for the fumigant gas is located on the chamber for the acid solution.

The composition for generating a fumigant gas in the form of a mixture of phosphine and carbon dioxide includes water, metal phosphide, acid, a substance forming in a chemical endothermic process

- 1 012509 carbon dioxide, and a binder, while the metal phosphide and the carbon dioxide forming substance are taken in amounts that provide a ratio of phosphine and carbon dioxide in the fumigant gas 1: (1.2-20.0) vol.h., and mixed with a binder, and acid and water are taken in a ratio of 1: (1-10) vol.h.

The fumigation method involves the inclusion of a device for generating a fumigant gas in the form of a mixture of phosphine and carbon dioxide, production of phosphine and carbon dioxide in the device with compensation for the heat generated by the chemical endothermic process, production of carbon dioxide in the reactor, and supply of the fumigant gas to the process the object due to the excess pressure created in the device upon receipt of phosphine and carbon dioxide, and the creation in the latter of the concentration field of the fumigant gas.

SUMMARY OF THE INVENTION

The disadvantages of such technical solutions to fumigation problems are as follows.

The presence of a binder in the mixture of reagents containing metal phosphide leads to the fact that, as gas is generated, phosphine from metal phosphide and carbon monoxide from a substance that forms carbon dioxide from the upper layers of the reagent mixture during a chemical endothermic process, a binder accumulates in them, which makes it difficult access of a mixture of acid and water to metal phosphide and a substance that forms carbon dioxide during the chemical endothermic process contained in the layers of the mixture of reagents located below the spent layers.

As a result, the rate of chemical reactions slows down and, in the end, the process of fumigant gas production can stop.

To eliminate the harmful effect of the binder on the fumigant gas production process in the proposed invention, the binder was excluded from the mixture containing metal phosphide, and instead a substance was introduced - an inhibitor of the chemical activity of metal phosphide and a substance that forms carbon dioxide during the chemical endothermic process, the density of which less than the density of the acid solution used.

A further disadvantage is that the method of generating a fumigant gas does not include the step of generating free volume over a mixture containing metal phosphide, immediately before starting the process of generating a fumigant gas, into which an acid solution is then fed.

The presence of a free volume over a mixture containing a metal phosphide during a certain period of time before the start of the fumigant gas production process leads to uncontrolled exposure of the atmosphere of this free volume to a mixture containing a metal phosphide and a decrease in its warranty period.

To eliminate this drawback in the proposed invention, immediately after receiving the mixture containing metal phosphide, it is placed in the first chamber in the form of an airtight shell in contact with the mixture at all points of its surface, and immediately before the fumigant gas is generated above the mixture or between the mixture and the shell form the free volume into which the acid solution is supplied.

To perform these operations, the proposed device instead of a locking element is equipped with a device for pressing the lid of the chamber containing a mixture of metal phosphide, a substance that forms carbon dioxide during the chemical endothermic process, and an inhibitor, to the surface of this mixture and a device for moving this lid relative to the mixture containing openings for communication cameras. When moving the lid, a free volume forms above the mixture, and openings open for communication of the chambers, through which a mixture of acid and water enters this formed free volume.

Another disadvantage is that the known method of fumigation of objects provides for the creation in them of a concentration field of a fumigant gas of constant value. However, the properties of insect pests suggest that the lethal dose of the toxic effect of phosphine gas on insect pests with a variable concentration of phosphine gas acting on them will be lower than with a variable concentration of phosphine gas, which will reduce the consumption of phosphine gas for fumigation.

To eliminate this drawback in the proposed invention, the fumigant gas is supplied to the fumigation object by a gas stream periodically, alternating periods when the fumigant gas is supplied to the object with periods when the fumigant gas is not supplied to the object.

It follows from the foregoing that the technical result of the invention is to ensure the operability of the composition for generating a fumigant gas and to ensure the production of the entire mass of the mixture containing metal phosphide in the device, increasing the shelf life and service life of the device used to implement the method, as well as reducing gas consumption fumigant in fumigation and increase its efficiency and environmental friendliness.

The specified technical result is achieved as follows.

In a method for generating a fumigant gas in the form of a mixture of phosphine with carbon dioxide, which involves the use of metal phosphide, water, acid, a substance that forms carbon dioxide in a chemical endothermic process, preliminary mixing of metal phosphide and a substance that emits carbon dioxide during a chemical endothermic process gas,

- 20152509 adding an acid solution to the resulting mixture to produce carbon dioxide simultaneously with phosphine and compensating for the heat released during phosphine production by the chemical endothermic carbon dioxide production process, a chemical activity inhibitor is introduced into the mixture of metal phosphide and a substance emitting carbon dioxide during the chemical endothermic process metal phosphide and carbon dioxide forming substance, the density of which is lower than the density of the acid solution, place it in an airtight shell in contact with the mixture at all points of its surface, and immediately before the production of the fumigant gas above the mixture or between the mixture and the shell, form a free volume into which the mixture of acid and water is fed.

In a device for generating a fumigant gas in the form of a mixture of phosphine and carbon dioxide, comprising a reactor comprising at least one unit of two interconnected chambers, the first of which is made in the form of an airtight shell and is designed to accommodate a mixture of metal phosphide, a substance forming in a chemical endothermic process, carbon dioxide, and the second, having an outlet for a fumigant gas, is designed for an acid solution, the reactor is equipped with a device for pressing the cover of the first chamber to the surface of the mixture metal osphide, carbon dioxide emitting substance, and an inhibitor and a device for moving at least a portion of this cap relative to the surface of the mixture containing metal phosphide, wherein one of the elements of the reactor has at least one opening with the possibility of different communication of the chambers through this opening or holes for various movements of the lid, depending on the temperature or the desired rate of production of the fumigant gas.

In a further embodiment of the device for generating a fumigant gas in the form of a mixture of phosphine and carbon dioxide, comprising a reactor, which is at least one unit of two interconnected chambers, the first of which is a sealed enclosure and designed to accommodate a mixture of metal phosphide, a substance, forming carbon dioxide during the chemical endothermic process, and the second chamber is for acid solution, while the second chamber has an outlet for the fumigant gas, and the reactor is equipped with moving the first camera relative to the lid of the second chamber, the first chamber cover is made in a protrusion on the lid of the second chamber, the first chamber and the housing has at least one opening for communicating chambers.

In this case, the first chamber for the mixture containing metal phosphide is placed above the mixture of acid and water inside the second chamber for acid and water or in the common casing of the two chambers, so that the lid of the first chamber moves in a direction parallel to the surface of the mixture of acid and water, and the device made with the possibility of its translation from vertical to horizontal.

The device may have a cover of the first chamber for the mixture containing metal phosphide, which consists of at least two parts, and is equipped with at least one device for pressing and one device for moving at least one part of the cover relative to the surface of this mixture.

The chambers can be communicated through the hole in the device for moving the lid only when the lid is removed from the surface of the mixture containing metal phosphide. Between the lid and the surface of the mixture can be installed gasket of an elastic chemically inert material.

A device for pressing the cover or at least one part of the cover to the surface of the mixture containing metal phosphide may be made in the form of a threaded connection;

at least two spring tightening brackets;

at least two flexible tie rods;

struts resting on the lid of the chamber for the mixture of acid and water or in the cylindrical shaft of the gate of the device for moving the lid relative to the surface of the mixture containing phosphide;

emphasis in the form of a pin placed on the cylinder of the moving device;

chamber for an acid solution, which is pulled with at least two rods to the chamber with a mixture containing metal phosphide.

A device for moving the lid or at least one part of the lid of the chamber with the mixture containing metal phosphide, relative to the surface of the mixture containing metal phosphide, can be made in the form of a hollow cylinder with at least one communication hole placed inside this mixture and / or above with this mixture with the possibility of abutment in the lid of the chamber for acid and water, and the traction unit, and the function of the movable lid or the movable part of the lid, pressed against the surface of the mixture containing metal phosphide, is carried out in the hollow cylinder orshen.

The device of the traction unit can be made in the form of a gate formed by a cylindrical rod inserted into the walls of the first chamber and / or into the walls of the strut resting on the cover of the second chamber, by a flexible rod connected to the piston;

an additional piston group located on the second chamber, to the piston of which a flexible rod is connected;

a piston rod acting as a cap or part of a cap;

flexible traction attached to the cover or part of the cover.

In the composition for generating a fumigant gas in the form of a mixture of phosphine and carbon dioxide, I include

- 3 012509 metal phosphide, a substance that forms carbon dioxide during the chemical endothermic process, taken in amounts that ensure the ratio of phosphine and carbon dioxide in the fumigant gas 1 :( 1.2-20.0) parts by weight, water and acid taken in the ratio 1: (1-10) parts by weight, an inhibitor is included further, the density of which is lower than the density of the acid solution used in the device.

As the carbon dioxide forming substance, for example, a salt of carbonic acid and / or carbamic acid or a mixture thereof can be used, and, for example, aluminum phosphide, magnesium phosphide, etc. can be used as a metal phosphide.

In the fumigation method involving the production of a fumigant gas as described above, the fumigant gas is supplied to the object to be processed due to the excess pressure generated during the production of the fumigant gas, and the gas fumigant concentration field is created in the latter.

When generating fumigant gas, you can use a portable device or device, the assembly and / or charging or recharging of which is carried out in the fumigation zone.

The supply of fumigant gas to the object can be carried out with a time delay - periodically.

In another embodiment of the method of fumigating an object that is a large volume filled with bulk product - the product array, for the case when a natural convective air flow passes through the product array, closing outside the product array, the fumigant gas is supplied from above or below the product array, depending on direction of the air flow so that the natural convective air flows the fumigant gas deep into the product periodically, alternating the period when the fumigant gas is supplied to the fumigat object and with the period when the fumigant gas is not supplied to the fumigation object, until the necessary mass of the fumigant gas is let in or when monitoring the state of insect pests in the object shows that they all died.

In a further embodiment of the method of fumigating an object in the form of a product array through which a natural air convective flow of alternating direction passes outside the product array, a fumigant gas is supplied from above and below the product array periodically, alternating between periods when the fumigant gas is supplied to the fumigation object with periods when the fumigant gas is not supplied to the fumigation object, matching the periods of supply of the fumigant gas to the fumigation object with the periods when the natural convective flow will transfer the feed fumigant gas deep into the fumigation facility until the necessary mass of fumigant gas is let in or when monitoring the status of insect pests in the facility shows that they have all died.

In another embodiment of the method of fumigating an object in the form of a product array through which natural convective air flow does not pass, or there are natural convective flows closed inside the product array, fumigant gas is supplied to the fumigation object periodically to the upper part of the fumigation object, alternating periods when the gas the fumigant is supplied to the fumigation object with periods when the fumigant gas is not supplied to the fumigation object until the required mass of fumigant gas is let in or when the condition is monitored asekomyh pests in the object will show that all of them died.

In this case, a fumigant gas can be supplied to the object, in which phosphine and carbon dioxide are in a ratio of 1: (1.2-20.0) vol.h. In this case, carbon dioxide can serve as a gas carrier, and not just a diluent gas.

The following options for a method for generating a fumigant gas, a device for generating a gas fumigant, compositions for generating a fumigant gas and a fumigation method are proposed for use in facilities for which it is important to minimize the time spent by operators performing fumigation at the fumigation facility.

In order to satisfy these conditions, in the method of fumigating such objects, devices for producing a fumigant gas together with transport pipes for a fumigant gas are placed on the surface of the product array, transport pipes are introduced into the product array, devices for generating a fumigant gas are launched, and after that fumigation operators leave the fumigation facility. The removal of devices for generating fumigant gas and transport tubes from the fumigation object is carried out after the completion of the entire time period when fumigation occurs.

In ship fumigation, the removal of devices for generating fumigant gas is already carried out at the port of discharge of the vessel. In this case, in order to evacuate phosphine gas adsorbed and absorbed, a stage of purging the devices for generating the fumigant gas and transport tubes with a low chemical activity gas is introduced in the devices for generating the fumigant gas and in the transport tubes. To this end, the composition for generating a fumigant gas is supplemented with a substance that produces a gas of low chemical activity mixed with an inhibitor of its chemical activity during a chemical or physico-chemical process, the degree of inhibition being higher than the degree of inhibition of metal phosphide and carbon dioxide forming substance in the endothermic process gas.

In a device for generating a fumigant gas in a first chamber for a mixture of metal phosphide, a substance that forms carbon dioxide in a chemical endothermic process, and an inhibitor of their chemical activity, or a substance may be placed in a second chamber for a mixture of acid and water,

- 4 012509 producing a gas of low chemical or physicochemical activity during a chemical or physicochemical process, mixed with an inhibitor of its chemical activity, providing a degree of inhibition greater than the degree of inhibition of the metal phosphide mixture and the substance forming carbon dioxide during the chemical endothermic process gas.

In the method of generating a fumigant gas, a substance can be additionally introduced into the composition of the starting materials, which forms a gas of low chemical activity during the chemical or physicochemical process, mixed with an inhibitor of its chemical activity, while providing a degree of inhibition greater than the degree of inhibition included in the composition of the starting materials of the metal phosphide and the substance forming carbon dioxide during the chemical endothermic process, which ensures the production of a gas of low chemical activity during trezka time greater than the time interval generating a fumigant gas.

List of drawings

In FIG. 1-8 are devices for generating a fumigant gas.

In FIG. 9-14 illustrate methods of fumigating objects in the form of arrays of products that require deep penetration of a fumigant gas, for example, a grain-filled silo or a ship's hold.

A device for generating a fumigant gas (Fig. 1) includes a reactor 1, which is at least one unit of two communicating chambers 2 and 3. In the first chamber 3 there is a mass of metal phosphide, a substance that forms carbon dioxide during the chemical endothermic process, and an inhibitor of the chemical activity of a metal phosphide and said carbon dioxide-forming substance. In the second chamber 2 is placed an acid solution.

On the lid of the chamber 2 there is an outlet 4 for a fumigant gas closed by a stopper. The chambers can communicate through the hole 5, if the cover 6 of the chamber 3, pressed against the mass containing phosphide, using the stop in the form of a pin 7, moves upward, forming a free volume above the surface of the mass containing phosphide and other reagents, and releases the hole 5. Then the acid solution through the hole 5 enters the resulting free volume, and the device will begin to produce a gas fumigant in the form of a mixture of phosphine and carbon dioxide.

Moving up can not entirely cover 6 of the chamber 2, but one part of the cover (Fig. 2) or several parts of the cover (Fig. 4).

The lid 6 can be pressed against the mass containing metal phosphide, with the help of a spacer in the form of a glass 8, abutting against the lid 9 of the chamber 2 (Fig. 2) or into the cylinder of the gate 10 (Fig. 3);

flexible rods 11, thrown over the gate 10 and the extension rods fixed to the ends of the chamber 3 (Fig. 4);

using a threaded connection 12 (Fig. 5);

using spring tightening brackets 13 (Fig. 6).

The traction node of the device for moving the cover or at least one part thereof can be made in the form of a gate formed by a cylindrical rod 10 inserted into the holes in the walls of the second chamber 2 for acid solution (Fig. 3);

a gate formed by a cylindrical rod 10 inserted into holes in the wall of the second chamber 2 and into the walls of the strut 8, and fixed relative to the chamber 3 by means of flexible rods 11 (Fig. 4);

in the form of an additional piston group 14 (Fig. 6);

in the form of a piston rod 15, which performs the function of a cover (Fig. 1), or in the form of a flexible rod 16 attached to the piston 17 (Fig. 2), or in the form of a threaded connection 12 (Fig. 5).

The threaded connection 12 of the cover and the chamber for the mixture containing metal phosphide (Fig. 5) performs both the function of pressing the cover to the mixture containing metal phosphide and the function of moving the cover relative to the surface of the mixture containing metal phosphide.

Another embodiment of the device, when not the lid is pressed against the mixture containing metal phosphide, but the chamber containing the metal phosphide moves and is pressed against the lid, the role of which is the protrusion on the lid for the chamber with a mixture of acid and water, is shown in FIG. 8. Here, the displacement and clamping unit is made in the form of a rod 18, its initial position, in which the mixture containing metal phosphide is pressed against the lid, the role of which is the protrusion 19, is fixed with the help of a pin 20. When moving the rod 18 down, it carries the camera down. 3 with a mixture containing metal phosphide, a free volume is formed between the mixture containing metal phosphide and the lid, holes 5 are opened between the chambers through which the mixture of acid and water enters the formed free volume, and the device starts working fumigant gas.

The advantage of such a device is that during storage of the device, the openings for communicating the chambers can be located above the level of acid and water, which excludes the possibility of the mixture of acid and water penetrating the mixture containing metal phosphide in the event of accidental leakage.

A further embodiment of the device is shown in FIG. 7. Here, chamber 3 for the mixture containing phosph

- 5 012509 metal feed, and the nodes for moving and pressing the cover are made in the same way as in the first embodiment of the device in FIG. 1, but a chamber is placed above the mixture of acid and water.

In this embodiment of the device, the operation of moving the lid or part thereof, forming a free volume above the mixture containing metal phosphide, and freeing the communication openings 5 between the cameras is not enough to start the fumigant gas production process. It is necessary to additionally transfer the device from a vertical position to a horizontal one. Then the level of the acid solution will be higher than the openings 5, and the acid solution will flow through the openings 5 into the free volume created by the operator just before start-up above the surface of the mixture containing the metal phosphide, and fumigant gas production will begin.

The device may be equipped with a unit for delaying the movement of the acid solution into the chamber 3 with a mixture containing metal phosphide. Such a unit may be, for example, a chemical, mechanical or electrical time relay. The delay in the time when the device starts or starts up allows the operator to complete all the start-ups of many reactors located in a large fumigation facility, exit the fumigation facility, seal the exit door without being exposed to the fumigant gas.

In addition, the device can be equipped with a node that implements its remote inclusion, which will allow the operator, being outside the fumigation object, to control the process of creating and maintaining the concentration field of the fumigant gas in the fumigation object, without being exposed to the gas fumigant.

An example implementation of the composition.

Take aluminum phosphide powder and carbonic salt powder in amounts that ensure the ratio of phosphine and carbon dioxide in the fumigant gas 1: (1.2-20), and with stirring, add an inhibitor until the particles are soaked in the mixture, but it is preserved loose condition. The resulting bulk mixture is placed in one of the two communicating chambers of the device. An acid solution is placed in the second chamber 2 of the device. When accessing the acid solution to the chamber 3 containing the above mixture, they are in contact with each other. As a result of chemical reactions, a mixture of phosphine and carbon dioxide gases is released. This mixture is the fumigant gas used to kill pests.

An aluminum phosphide powder and a powder of a carbamic acid salt or other salt emitting carbon dioxide are taken in contact with water in amounts that provide a ratio of phosphine to carbon dioxide in the fumigant gas of 1: (1.2-20), and the inhibitor is added while stirring the moment when the particles of the mixture were impregnated, but its loose state was preserved. The resulting bulk mixture is placed in one of the two communicating chambers of the device. Water is placed in the second chamber of the device. When providing access to water in the chamber containing the above mixture, they are in contact with each other. As a result of chemical reactions, a mixture of carbon dioxide phosphine gases and ammonia is released. This mixture is the fumigant gas used to kill pests.

A method of producing a fumigant gas and fumigation using this device and this composition is as follows.

The operator turns on the device by moving the cover 6 of the chamber 3 from the state pressed up to the surface of the mixture containing metal phosphide, and a free volume forms above the surface of the mixture containing metal phosphide and the acid solution is accessible from the reactor chamber 2 through openings 5 into this formed free volume of the chamber 3. The time delay control means, if installed, provides a predetermined interval necessary and sufficient to perform the final operations of preparation fumig tion, the operator’s exit from the zone of fumigation and sealing of the object.

After a predetermined time interval, a mixture of acid and water enters this volume.

The acid solution, having entered the chamber with a mixture of metal phosphide, a substance that forms carbon dioxide during the chemical endothermic process, and an inhibitor substance, is first contacted with the inhibitor, which is impregnated with each particle of the mixture and which, due to the fact that its density is lower than the density of the acid solution, begins to emerge, thinning the inhibitor film over particles of metal phosphide and a substance that forms carbon dioxide during the chemical endothermic process. Then comes the moment when the upper layer of mixed particles of metal phosphide and a substance that forms carbon dioxide during the chemical endothermic process is in contact with a mixture of acid and water.

In this case, parallel chemical reactions proceed: the exothermic reaction of the formation of phosphine and the endothermic process of the formation of carbon dioxide. The result is a gas fumigant. The heat generated during the formation of phosphine is compensated by the chemical endothermic process of carbon dioxide formation, and the inhibitor, which is impregnated with each particle of the mixture, as well as the surface layer of the inhibitor, floats to the surface of the acid solution.

The spent top layer of the mixture containing metal phosphide exposes a new layer, which is worked out, like the top layer. This process goes before the entire mass of the mixture containing metal phosphide is consumed.

- 6 012509

The ratio of metal phosphide and the substance that forms carbon dioxide during the chemical reaction is such that phosphine and carbon dioxide are formed in a ratio of 1: (1.2-20.0) vol.h., and the ratio of acid to water in the solution is selected within 1: (1-10.0) parts by weight, which allows the process to be carried out with the necessary compensation for the heat released during the formation of phosphine. Thus, the production of gas fumigant is carried out without overheating of the reaction mass.

The supply of fumigant gas to the processed object is carried out under the influence of excess pressure created in the device due to the energy of chemical reactions during the formation of phosphine and carbon dioxide. The supply of fumigant gas to the processed object, which is a large array of product, which requires deep penetration of the fumigant gas into the product, is carried out using the so-called "pulsed gravitational technology" (Fig. 9, 10). In this case, a gas with a carrier gas density increased with respect to air is selected. Using the line (pipe) 21 form the flow of carrier gas from its source 22 into the mass of the product, while the driving force of the flow is provided due to gravitational forces. Using the line 23, a fumigant gas is introduced into the gas carrier stream thus formed via line 23 in a pulse manner (alternating between periods when the fumigant gas is supplied and periods when the fumigant gas is not supplied). Allowed for a period of time when the fumigant gas is not supplied, do not apply the carrier gas. This is achieved, for example, by turning on each subsequent generator after working out the previous one with a time delay. This allows the delivery of fumigant gas pulses to the deep layers of the product.

"Pulse gas gravity technology" in the case of using carbon dioxide as a carrier gas can be provided without the use of a special carrier gas source and a carrier line for the carrier gas flow. This is achieved by a greater enrichment of the gas fumigant with carbon dioxide during its production in devices 24, 25, 26 and a pulsed supply of a more fumigant-rich carbon dioxide gas to the object using line 23 (Fig. 9). The ratio of phosphine and carbon dioxide in the fumigant gas in this case can be 1: (1.2-20.0) vol.h.

Such a technology can be applied if there are no convective flows in the processed object (Fig. 9, 10) or if convective air flows are closed in the product array subjected to fumigation (Fig. 11).

If a natural convective air flow passes through the fumigation object in the form of a product array and closes outside the product array, the fumigant gas is pulsed through the top or bottom of the product array, depending on the direction of the convective flow. Each fumigant gas supply pulse forms a fumigation wave in the form of a layer saturated with a fumigant gas. Then these layers of fumigant gas move through the fumigation object under the influence of convective flow (Fig. 12, 13).

In another embodiment, when the direction of the natural convective air flow in the fumigation object changes during the fumigation period, the fumigant gas is introduced above and below the object (Fig. 14), matching the supply of the fumigant gas to the object with the periods of existence of the natural convective air flow directed deep into the array product.

Thus, an advantage of the invention is the following:

the production of the entire mass of the mixture containing metal phosphide is ensured, and the gas-fumigant is produced more uniformly throughout the entire period of operation of the device;

storage and performance of a mixture containing metal phosphide is ensured during the entire warranty period of the composition and device;

the cost of fumigation and its complexity are reduced, and the cost-effectiveness and convenience of its implementation and environmental friendliness are increased, since a smaller mass of fumigant gas is used to achieve the goal of fumigation, and therefore there are fewer devices for generating fumigant gas and less impact on the environment.

Claims (24)

CLAIM 1. A method of generating a fumigant gas containing phosphine and carbon dioxide, which involves the use of metal phosphide as a starting reagent, a substance emitting carbon dioxide in a chemical endothermic process, and an acid solution, wherein the metal phosphide and the substance emitting carbon dioxide are pre-mixed and an acid solution is added to the resulting mixture to produce carbon dioxide simultaneously with phosphine and to compensate for the heat generated during phosphine production by chemical endothermic percent carbon dioxide formation process, characterized in that an inhibitor of the chemical activity of a metal phosphide and a substance emitting carbon dioxide is introduced into said mixture, the inhibitor density being lower than the acid solution density, the mixture is placed in an airtight shell in contact with the mixture over the entire surface of the shell, and immediately before the formation of a fumigant gas between the mixture and the shell forms a free volume into which an acid solution is supplied. 2. Device for generating a fumigant gas containing phosphine and carbon dioxide, comprising a reactor (1), which is at least one unit of two interconnected - 7 012509 chambers (2, 3), the first (3) of which is an airtight shell and is designed to accommodate a mixture containing metal phosphide and a substance that forms carbon dioxide during the chemical endothermic process, and the second (2) having an outlet ( 4) for a fumigant gas, it is intended for an acid solution, characterized in that it is equipped with a device for pressing the cover (6) of the first chamber (3) to the surface of the mixture, into which an inhibitor of the chemical activity of the components of this mixture is introduced, and a device for moving along enshey least a portion of the cover relative to the surface a mixture which comprises at least one opening providing communication opportunity chambers (2, 3) for interacting between an acid solution with said mixture and produce a fumigant gas. 3. The device according to claim 2, characterized in that the first chamber is placed inside the second chamber so that the chambers are communicated above the level of the acid solution, this device allows the lid of the first chamber to be moved in a direction parallel to the surface of the acid solution, and the device is arranged to translate it from vertical to horizontal. 4. The device according to claim 2, characterized in that the first and second chambers have a common housing and communicated through at least one hole made in a common partition. 5. The device according to claim 2, characterized in that the first chamber is placed inside the second chamber so that said device allows the cover of the first chamber to move in a direction parallel to the surface of the acid solution, and the device is configured to translate it from a vertical position to a horizontal one. 6. Device according to any one of paragraphs.2-5, characterized in that the lid of the first chamber is made of at least two parts, and the device is equipped with at least one clamping device and at least one device for moving at least one part of the lid relative to the surface of the mixture containing metal phosphide. 7. The device according to claim 6, characterized in that between the cover of the first chamber and the surface of the mixture is installed a gasket of an elastic chemically inert material. 8. A device according to any one of claims 2 to 5, characterized in that the clamping device and the device for moving the lid of the first chamber form a threaded connection. 9. The device according to any one of paragraphs.2-5, characterized in that the clamping device is made in the form of at least two spring tightening brackets. 10. Device according to any one of paragraphs.2-5, characterized in that the preload device is made in the form of at least two flexible tightening rods. 11. The device according to any one of paragraphs.2-5, characterized in that the clamping device is made in the form of a spacer abutting against the lid of the second chamber. 12. The device according to claim 11, characterized in that the spacer is made in the form of a glass having holes in the side wall and in the bottom. 13. The device according to one of paragraphs.2-5, characterized in that the device for moving at least part of the cover consists of a hollow cylinder with at least one communication hole and a traction unit, while the movable cover or the movable part of the cover is made in the form placed in a hollow piston cylinder. 14. The device according to item 13, wherein the traction node is made in the form of a gate formed by a cylindrical rod inserted into the walls of the second chamber. 15. The device according to item 13, wherein the traction unit is made in the form of a piston group located in the second chamber. 16. The device according to item 13, wherein the traction node is made in the form of a piston rod that acts as a cover or at least one part of the cover of the first chamber. 17. The device according to item 13, wherein the traction node is made in the form of flexible traction. 18. Device for generating a fumigant gas containing phosphine and carbon dioxide, including a reactor (1), consisting of at least one unit of two interconnected chambers (2, 3), the first (3) of which is a sealed enclosure and is designed to accommodate a mixture containing metal phosphide and a substance that forms carbon dioxide during the chemical endothermic process, and the second (3), having an outlet for the fumigant gas, is intended for an acid solution, characterized in that it is equipped with a device (18) to move the first camera (3), and the cover of the first camera is made in the form of a protrusion (19) on the cover (9) of the second camera (2), while the housing of the first camera (3) has at least one opening for communication of the cameras when moving the first cameras relative to the second. 19. A composition for generating a fumigant gas containing phosphine and carbon dioxide, comprising an acid solution with an acid-water ratio of 1: (1-10) parts by weight, metal phosphide, a substance that emits carbon dioxide in a chemical endothermic process, characterized in that it additionally contains an inhibitor of the chemical activity of metal phosphide and a substance emitting carbon dioxide, moreover, the density of the inhibitor is less than the density of an acid solution, and metal phosphide and a substance emitting carbon dioxide are taken in quantities that provide an image phosphine and carbon - 8 012509 carbon dioxide in the ratio 1: (1.2-20.0) vol.h. and mixed with an inhibitor. 20. The method of fumigation, including the production of fumigant gas according to claim 1 and its supply to the fumigation object due to the excess pressure created by the production of this gas. 21. The method according to claim 20, characterized in that the fumigant gas is supplied to the fumigation object periodically. 22. The method according to claim 20, characterized in that when fumigating an object in the form of a product array, the fumigant gas is supplied to the fumigation object through which a natural convective flow passes, closing outside the product array, periodically from above or below the product array, depending on the direction convective air flow. 23. The method according to claim 20, characterized in that when fumigating an object in the form of a product array, the fumigant gas is supplied to the object through which a natural convective flow of a variable direction passes, closing outside the product array, periodically from above and below the product array, coordinating the periods supply of fumigant gas with periods of existence of a natural convective flow directed deep into the product array. 24. The method according to claim 20, characterized in that when fumigating an object in the form of a product array, a fumigant gas is supplied to the upper part of the product array periodically.