SU1370097A1 - Device for desalination of salt water - Google Patents

Abstract

The invention relates to the desalination of salt water by the crystal hydrate method and can be used in gas hydrate desalination plants. The purpose of the invention is to increase the efficiency of the installation due to the use of pressure arising from the melting of crystalline hydrates in a closed volume. The water desalination plant contains a pipeline for the supply of salt water, a deaerator connected in series with pipelines, pumps and valves, a crystallizer, a propellant column, a floater, a separator and a degasser, pipelines for removal of crystalline hydrates, hydrate forming agent and fresh water. The installation is additionally equipped with a brine receiver, and the melter through an elastic partition is equipped with a reverse osmosis desalination chamber with a freshwater storage tank, the chamber through a deaerator connected to the pipeline for feeding saline water, and connected to the crystallizer through the brine receiver. When desalinating water at the proposed facility, it is possible to obtain an additional 0.2 kg of desalinated water per 1 kg of desalinated water, which is equivalent to a reduction in energy consumption by 20%. 1 il. i (L 00

Description

with

The invention relates to the desalination of seaweed, saline, and also mineralized wastewater using the crystal hydrate method and can be used in gas hydrate desalination plants.

The purpose of the invention is to increase the efficiency of the installation due to the use of pressure arising from the melting of crystalline hydrates in a confined space.

The drawing schematically shows the proposed installation.

The installation consists of a mold 1, equipped with a heat exchanger 2, a pump 3, a wash column 4, in the middle of which there is a pocket 5 with a filtering mesh 6, and

agents of type SC, C1, CH, CHF, CHP2, C1, and others, which increase the volume of the system during the decomposition of crystalline hydrates into water and liquid hydrate-forming agent.

The source salt water through the desalter 18, where dissolved gases are removed from it, is fed through pipelines with valves 17 and 19 and the brine receiver 20 to the crystallizer 1, in which it is in contact with R-22 at a temperature K and pressure “0, 6 8 MPa, resulting in the formation of crystalline hydrates. The formation of crystalline hydrates is accompanied by the release of heat, which is removed by a cold source pumped through heat exchanger 2. Brine with crystalline

the upper part has a drive with 7 hydrates and 20 rats with a pump 3 under pressure

The mobile suspension, the melter 8, equipped with a flexible partition 9, has a built-in heat exchanger 10 and is connected to the storage 7 of hydrate suspension by a pipeline with a valve 11 for draining the hydrated hydrate and a separator 12 by a pipeline with a valve 13, the pipeline is equipped with a filter 1А. Through the elastic partition, the melter is additionally equipped with a reverse osmosis desalination chamber with a membrane 15 and a reservoir 16 of desalinated water, having an outlet to the consumer. The chamber is connected by pipeline with valve 17 to deaerator 18 and pipeline for supplying salt water to the installation, and by pipeline to valve 19 through brine receiver 20 to mold 1. Separator 12 is connected to degasser 21 by pipeline 22, to the top of the production column 4 through pump 23 by pipeline 24 return desalinated water.

A pipeline 25 for removal of hydrates 45 is advanced into the upper part of the proto-forming agent — with mold 1. Pocket 5 of wash column 4 is connected by pipe 26 for removal of brine with mold 1 and is equipped with pipeline 27 for 50 ta crystalline hydrates. From storage

reset the brine from the installation. The mold 1 is connected to the receiver 20 of the brine pipeline 28. The drainage of fresh water to the consumer, as well as the input to the salt water installation in the drawing are indicated by arrows. In the presented example, the operation of the plant is considered using R-22 or

 0.93 MPa is fed to the bottom of the wash column 4. Under the action of a pressure differential between the top and bottom of the wash column

(usually 0.07-0.1 mPa) suspension (brine and crystalline hydrates) moves upward, passing through the section with filtering mesh 6, on which the suspension is dried due to separation of the brine under the action of pressure difference before and after the filtering mesh. The brine accumulates in pocket 5, from which it is divided into two streams: one is recycled into

the mold 1 through line 26, and the other through line 27 is removed from the installation. A porous hydrate begins to form at the exit from the filter net 6, in which hydrates are washed from the surface brine film by countercurrent filtration of the fresh wash water supplied by the pump 23. The washed wash column crystals, where they are discharged into the accumulator 7, in which they mix with desalinated water required for further hydrotransporhydrates hydrates along with water hydrotransport served in the melter

8 through the pipeline with a valve 11. At the same time open the valve 13. Water

through the filter 14 and the pipeline with the valves 13 is circulated to the separator 12, and the hydrates are trapped by the filter 14 and accumulate in the melter 8. After the part is completely filled, melt

l with a heat exchanger 10 hydrates first shut the valve 13, and then 11, to prevent the gas phase in the melter, and also close the valve 19 and completely fill the original salt water-reverse osmosis desalination chamber equipped with a membrane 15 and partitioned off from the hydrates by an elastic partition 9 and then close the valve 18. Then the hot coolant is supplied to the heat exchanger 10, as a result of which the hydrates are heated to 291-292 (1.5-2 ° C / s above the equilibrium temperature of the existence of the hydrates) and decomposed into and liquid R-22, while the volume of the system increases, as a result of which the pressure grows and is transmitted through an elastic partition, the latter sags, pushing water through the membrane 15, as a result of which desalination takes place using a reverse osmosis method. Since the liquid is practically not compressible, and a closed volume creates pressure, sufficient for desalination of water by the method of reverse osmosis. Desalinated water accumulates in accumulator 16 and is discharged to consumer. After decomposition of all hydrates, heat supply to heat exchanger 10 is stopped, valve 13 is opened and liquid mass (mixture of desalinated water and liquid R-22) is opened into separator 12, valve 11 is simultaneously opened, and the melter is filled with a new portion of hydrates from storage pool 7 . At the same time, the valve 19 and the water with a high salt content are opened, but compared to the original salt water, since part of the fresh water has already been extracted when it is pushed through the filter element (membrane) 15, it is drained into the brine receiver 20, from which later on into the mold 1 to form a new batch of crystalline hydrates, after which the valve 17 is opened and the reverse osmosis desalination chamber is refilled with the original salt water. In the separator 12

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produce desalinated water and liquid P-22 under the action of, for example, the density of the densification point (1000 kg / m3, p. 1200 kg / cm. Liquid R-22 is recirculated to the mold 1 through conduit 25, where it again contacts the solution and forms crystalline hydrates, and the desalinated water is pumped partially by pump 23 to the industrial column 4, and partially through pipeline 22 to the degasser 21, where dissolved gases are removed, and then withdrawn to the consumer. Then the cycle is repeated.

The advantage of the proposed installation in comparison with the prototype is to increase its efficiency, since during the operation of the proposed installation it is possible to additionally receive 0.2 kg of desalinated water practically without additional energy costs, which is equivalent to reducing energy consumption by 20% when desalinating salt water compared to with a prototype.

Claims (1)

Invention Formula An installation for desalination of salt water, containing a pipeline for supplying salt water, a deaerator connected in series with pipelines, pumps and valves, a crystallizer, a washing column, a melter, a separator and a degasser, pipelines for removing brine of crystalline hydrates, a hydrating generator and fresh water, differ- so that, in order to increase the efficiency of the installation due to the use of pressure arising from the melting of crystalline hydrates in a closed volume, it is additionally equipped with a brine receiver and the melter is supplied through an elastic partition with a reverse osmosis desalination chamber with a freshwater storage tank, the chamber through the deaerator connected to the pipeline for feeding salt water, and connected to the crystallizer through a brine receiver.