RU2805063C1 - Method for decomposition of gas hydrates - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention can be used in gas production in continental and offshore fields of natural hydrates, as well as in the elimination of man-made hydrates in systems for the collection, preparation and transport of hydrocarbon raw materials. The proposed method for the decomposition of gas hydrates involves contact with them of a reagent that promotes their dissociation. A reagent containing a mixture of ammonium nitrate and sodium nitrite or sodium nitrite and ammonium chloride is used. Also used are reagents containing a mixture of ammonium nitrate and sodium nitrite, or a mixture of sodium nitrite and ammonium chloride, or a mixture of sodium nitrite, urea and hydrochloric acid, or a mixture of sodium nitrite, urea and sulfamic acid, or a mixture of sodium nitrite, urea and nitric acid, or a mixture of ammonium sulfamate, sodium hypochlorite and aqueous ammonia solution. An exothermic reaction is carried out to produce additional antihydrate substances.

EFFECT: invention improves the efficiency of hydrate decomposition.

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Description

The invention relates to the field of gas and oil industries. It can be used in gas production in continental and offshore fields of natural hydrates, as well as in the elimination of man-made hydrates in systems for the collection, preparation and transport of hydrocarbon raw materials.

There is a known method for the decomposition of gas hydrates by supplying heat from exothermic reactions to the dissociation zone of hydrates, selecting the released hydrocarbon gas and liquid, and exothermic reactions are carried out outside the decomposition zone of gas hydrates, the energy obtained from exothermic reactions is converted into electrical energy, with the help of which provide a mode of decomposition of gas hydrates in one or several zones of gas hydrates, for which a high-pressure coolant is heated with electric energy and supplied to a distance along the zone of destruction of gas hydrates from the place of its input (RF Patent No. 2424427 C1).

The disadvantage of the considered method is a multi-stage process, which consists in performing exothermic reactions outside the contact zone with hydrates, and the heat obtained from these reactions is converted into electrical energy, which is then used for the decomposition of hydrates. At each stage of this process, energy losses occur: both thermal and electrical, which reduces the energy efficiency and overall efficiency of hydrate decomposition.

The closest in technical essence and achieved result to the proposed one is the method of decomposition of gas hydrates by contacting an antihydrate reagent, for example, methanol with them (AS USSR No. 390257, M.Kl. ² E21B 43/00. publ. 07/11/73. Bulletin No. 30).

The disadvantage of this method is the use of methanol, which is necessary for the decomposition of gas hydrates, which entails:

- transportation and storage in specially equipped warehouses of this toxic substance;

- deterioration of the environmental situation.

These disadvantages negatively affect the overall effectiveness of the method.

The objective of the present invention is to increase the efficiency of hydrate decomposition.

The technical result is a complex effect on the hydrate by the physicochemical and exothermic reactions of the reagent.

The technical result is achieved by the fact that in the method of decomposition of gas hydrates, including contact with them of a reagent that promotes their dissociation, what is new is that a reagent is used containing a mixture, with the help of which an exothermic reaction is carried out to produce additional antihydrate substances.

Also new is that the mixture contains ammonium nitrate and sodium nitrite.

Also new is that the mixture contains sodium nitrite and ammonium chloride.

Also new is that the mixture contains sodium nitrite, urea and hydrochloric acid.

Also new is that the mixture contains sodium nitrite, urea and sulfamic acid.

Also new is that the mixture contains sodium nitrite, urea and nitric acid.

In addition, what is new is that the mixture contains mineral salts of hydrazine or hydroxylamine (chlorides, nitrates, sulfates) and sodium nitrite.

Also new is that the mixture contains ammonium sulfamate, sodium hypochlorite and aqueous ammonia.

The technical method, which consists in using a reagent containing a mixture with which an exothermic reaction is carried out to produce additional antihydrate substances, allows for a complex effect on the hydrate by physicochemical and exothermic reactions.

The technique consists in the fact that the mixture contains ammonium nitrate and sodium nitrite, which allow an exothermic reaction to occur:

producing thermal energy in an amount of 314 kJ/mol and antihydrate products (nitrogen and an aqueous solution of sodium nitrate), which have a physical and chemical effect on the hydrate.

The technique consists in the fact that the mixture contains sodium nitrite and ammonium chloride, which allow an exothermic reaction to occur:

with the production of thermal energy in the amount of 309 kJ/mol and antihydrate products (nitrogen and an aqueous solution of sodium chloride), which have a physical and chemical effect on the hydrate.

The technical technique is that the mixture contains sodium nitrite, urea and hydrochloric acid, which allow an exothermic reaction to occur:

with the production of thermal energy in the amount of 852 kJ/mol and antihydrate products (nitrogen and an aqueous solution of sodium chloride), which have a physical and chemical effect on the hydrate.

The technique consists in the fact that the mixture contains sodium nitrite, urea and sulfamic acid, which allow an exothermic reaction to occur:

with the production of thermal energy in the amount of 1474 kJ/mol and antihydrate products (nitrogen and an aqueous solution of sodium sulfate), which have a physical and chemical effect on the hydrate.

The technique consists in the fact that the mixture contains sodium nitrite, urea and nitric acid, which allow an exothermic reaction to occur:

with the production of thermal energy in the amount of 789 kJ/mol and antihydrate products (nitrogen and an aqueous solution of sodium nitrate), which have a physical and chemical effect on the hydrate.

A technique in which the mixture contains ammonium sulfamate, sodium hypochlorite and an aqueous ammonia solution, which allows an exothermic reaction to occur:

with the production of thermal energy in an amount of 1700 kJ/mol and antihydrate products (nitrogen, ammonium sulfate and an aqueous solution of sodium chloride), which have a physical and chemical effect on the hydrate.

The authors are not aware of the existing prior art to increase the efficiency of hydrate decomposition in this manner.

The implementation of the method is illustrated by the following example.

A method for the decomposition of gas hydrates, including contact with them of a reagent that promotes their dissociation, and a reagent is used containing a mixture with which exothermic reactions (1) - (6) are carried out to produce heat from 309 to 1700 kJ/mol and additional antihydrate substances ( aqueous solutions of sodium nitrate, sodium chloride, sodium sulfate and ammonium sulfate and nitrogen).

Thus, the combination of essential features allows us to achieve the desired technical result.

Claims (1)

A method for the decomposition of gas hydrates, including contact with them of a reagent that promotes their dissociation, characterized in that a reagent is used containing a mixture of ammonium nitrate and sodium nitrite, or a mixture of sodium nitrite and ammonium chloride, or a mixture of sodium nitrite, urea and hydrochloric acid, or a mixture sodium nitrite, urea and sulfamic acid, or a mixture of sodium nitrite, urea and nitric acid, or a mixture of ammonium sulfamate, sodium hypochlorite and an aqueous solution of ammonia, with the help of which an exothermic reaction is carried out to obtain additional antihydrate substances.