Seawater desalination and salinity production plant

Abstract

To provide a combination of a seawater desalination apparatus and a salinity production apparatus simplifying a steam supply system, enabling efficient production of freshwater and salt without discharging any treated seawater externally.SOLUTION: A steam supply and distribution system comprising two circuits is formed, equipped with a steam distribution apparatus connected to a steam source, to distribute steam supplied from the steam source to a seawater desalination apparatus and a salinity production apparatus. In the seawater desalination apparatus, steam distributed from the steam distribution apparatus flows through pipes, undergoes heat exchange with supplied seawater to generate steam, and produces freshwater. The salinity production apparatus introduces steam distributed from the steam distribution apparatus into the space between an outer tube and an inner tube. Concentrated seawater introduced from a distillation tower is introduced into the interior of the inner tube, where water is evaporated to produce salt. A steam collection and recovery system comprising two lines is formed, condensing steam from both the seawater desalination apparatus and the salinity production apparatus in a condenser.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a seawater desalination and salt production plant. [Background technology]

[0002] There are various methods for desalination of seawater, but currently the most well-known are the multi-stage flash evaporation method, the multi-effect evaporation method, and the reverse osmosis membrane method.

[0003] Meanwhile, in Japan, a salt production method was developed in which seawater was concentrated and crystallized. In this case, seawater with a salinity of 3% was concentrated to produce concentrated seawater with a salinity of 20%, which was then evaporated to produce salt.

[0004] Because the seawater desalination plant and the salt production plant are operated as separate plants, the weak brine produced in the primary concentration process at the salt production plant has been discarded as waste, and the concentrated brine produced at the desalination plant has also been discarded as waste.

[0005] It has been proposed to combine these two plants and use what was previously wasted in each as a useful product, thereby reducing the costs of producing fresh water and salt, as well as the cost of the equipment.

[0006] Patent Document 1 describes a method for desalination and salt production of seawater, which includes a salt production process in which seawater is separated into concentrated brine and weak brine through a primary concentration process, and salt is precipitated from the concentrated brine through a secondary concentration process using evaporation.The weak brine from the primary concentration process is desalted in a desalination device to obtain fresh water, and the concentrated brine produced in the desalination device is returned to the primary concentration process. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 8-318136 [Patent Document 2] Japanese Patent Application Laid-Open No. 2914-117653 Summary of the Invention [Problem to be solved by the invention]

[0008] There is a need to combine both plants using an evaporation method, simplify the steam supply system, and efficiently produce fresh water and salt without discharging the treated seawater to the outside. The devices described in the above patent documents cannot meet this need.

[0009] The present invention addresses this need by combining the two plants, simplifying the steam supply system, and enabling the efficient production of fresh water and salt without discharging treated seawater to the outside. [Means for solving the problem]

[0010] The present invention relates to a seawater desalination and salt production plant comprising a seawater desalination plant that produces fresh water from seawater, and a salt production plant that produces salt from concentrated seawater produced by the seawater desalination plant, the seawater desalination apparatus comprises a distillation column having a seawater supply source, a steam source, and a pipe through which steam from the steam source flows, and which generates steam from seawater by performing heat exchange between the seawater supplied from the seawater supply source and the steam supplied from the steam source and flowing through the pipe; a cooling water circulator; and a condenser connected to the cooling water circulator and which introduces circulating cooling water to condense the generated steam; The salt production device is composed of a double pipe of an outer pipe and an inner pipe, and steam is introduced into the space between the outer pipe and the inner pipe. A screw device that can be rotated by a drive source is disposed inside the inner pipe. Concentrated seawater introduced from the distillation column is introduced into the inner pipe, and seawater with an increased concentration is produced as the screw device rotates and moves by heat exchange with the steam, and water is evaporated to produce salt. a steam distribution device connected to the steam source, forming two steam supply distribution systems that distribute the supplied steam to the seawater desalination device and the salt production device; In the seawater desalination apparatus, steam distributed from the steam distributor flows through the pipe and exchanges heat with supplied seawater to generate steam and produce fresh water; The salt production apparatus introduces steam distributed from the steam distributor into a space between the outer pipe and the inner pipe, introduces concentrated seawater introduced from the distillation column into the inside of the inner pipe, evaporates water, and produces salt; Forming two steam collection and recovery systems that collect and recover steam output from both the seawater desalination plant and the salt production plant in the condenser for condensation. We provide a seawater desalination and salt production plant characterized by the above. [Effects of the Invention]

[0011] According to the present invention, by providing the steam distribution device and the condenser, two steam supply and distribution systems can be formed, and two steam collection and recovery systems can also be formed, thereby simplifying the steam supply system and efficiently producing fresh water and salt without discharging part of the treated seawater to the outside. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing a system of a seawater desalination and salt production plant according to an embodiment of the present invention. FIG. 1 is a diagram showing a system of a seawater desalination and salt production plant according to an embodiment of the present invention.

[0013] An embodiment of the present invention is characterized in that by providing the steam distribution device and the condenser, two steam supply and distribution systems can be formed, and two steam collection and recovery systems can be formed, making it possible to efficiently produce fresh water and salt without discharging a portion of the treated seawater to the outside.

[0014] The following description will be given with reference to the drawings. An embodiment of the present invention relates to a seawater desalination and salt production plant including a seawater desalination apparatus that produces fresh water from seawater, and a salt production apparatus that produces salt from concentrated seawater produced by the seawater desalination apparatus.

[0015] In FIG. 1, a seawater desalination and salt production plant 1 is composed of a seawater desalination plant 2 and a salt production plant 3.

[0016] The seawater desalination plant 2 includes a seawater tank 4 that is a seawater supply source, a boiler 5 (for example, evaporation rate 500 kg / h, maximum pressure 0.98 MPa, heavy oil fuel) that is a steam source, a distillation column 6 that has a pipe 7 inside through which steam from the steam source flows and that generates steam from the seawater by performing heat exchange between the seawater supplied from the seawater supply source and the steam supplied from the steam source and flowing through the pipe, a cooling water circulation device (also called a chiller, for example, capacity 30.3 kW) 10, and a condenser 8 that is connected to the cooling water circulation device 10 and introduces circulating cooling water to condense the generated steam.

[0017] The distillation column 6 is composed of an inner vessel 7A incorporating a pipe 7 and an outer vessel 7B.

[0018] The seawater desalination plant 2 further includes a pail 9 for storing fresh water, a thermometer 11 for measuring the temperature inside the distillation column, and a motor 14 as a drive source for rotating an agitator 12 inside the distillation column and an agitator 13 attached to the tip of the agitator 12 inside the distillation column.

[0019] A pump 15 for introducing seawater and an inverter-controlled motor 16 for driving the pump 15 are provided between the seawater tank 4 and the distillation column 6. Seawater is introduced into the top of the distillation column 6 through a seawater inlet 51 provided at the top of the distillation column 6.

[0020] The vapor that has flowed through the pipe is led out from the top of the distillation column 6 to the condenser 8 .

[0021] The salt production plant 3 includes a salt separator 20 having a double-pipe configuration consisting of an outer pipe 21 and an inner pipe 22, a screw device (sometimes called a screw propeller) 23 which is a spiral extrusion device disposed inside the inner pipe, and an inverter-controlled motor 24 which is the drive source for the screw device 23. The salt separator 20 is disposed at an angle, with the concentrated seawater inlet 32 ​​on the lower side and the steam inlet 42 on the upper side. The concentrated seawater inlet 32 ​​is provided at the lower end of the inner pipe 22, the outlet 33 for steam after salt precipitation is provided at the upper end of the inner pipe 22, and the steam inlet 42 from the steam distributor 41 is provided at the upper end of the outer pipe 21.

[0022] A steam outlet 43 is provided at the lower end of the outer pipe 21. The introduced concentrated seawater flows from bottom to top in the inner pipe, and the steam flows from top to bottom in the outer pipe. The concentrated seawater and steam flow in opposite directions through the inner pipe 22 and the outer pipe 21, respectively.

[0023] A steam distributor 41 is provided connected to a boiler 5 which is a steam source, and a system is formed to distribute the steam supplied from the boiler 5 to the seawater desalination plant 2 and the salt production plant 3.

[0024] A pipe 61 is provided connecting the seawater tank 4 and the distillation column 6, and a pipe 62 is provided connecting the boiler 5 and the steam distributor 41. The steam distributor 41 may be attached directly to the boiler 5 without the pipe 62.

[0025] An upstream pipe 63 connecting the cooling water circulation device 7 and the condenser 8, a downstream pipe 64, a pipe 66 connecting the pipe 7 and the condenser 8, a pipe 67 connecting the steam distribution device 41 and the top of the outer can, a pipe 68 connecting the steam distribution device 41 and the inlet of the pipe 7, a pipe 69 connecting the steam distribution device 41 and the steam inlet 42 of the outer pipe 21, a pipe 70 connecting the outlet of the pipe 7 and the condenser 8, a pipe 71 connecting the bottom of the inner can 7A of the distillation column 6 and the inner pipe 22 of the salt separator 20, a pipe 72 connecting the pipe 66 and the bottom of the outer can 7B, a pipe 73 connecting the pipe 66 and the outlet 42 of the outer pipe 21 of the salt separator 20, and a pipe 74 connecting the pipe 66 and the outlet 33 of the inner pipe 22 of the salt separator 20 are provided.

[0026] The pipes 70, 72, 73, and 74 may be connected directly to the condenser 8 without using the pipe 66. However, it is recommended from the viewpoint of pipe installation efficiency that the steam collected in the pipe 66 be introduced into the condenser 8.

[0027] The steam collected in the pipe 66 is collected in the condenser 8 and condensed, forming a collection, recovery and condensation system.

[0028] The concentrated saltwater flowing inside the inner pipe 22 becomes even more concentrated due to the heat exchange, and finally, salt precipitates inside the inner pipe, and the treated steam after salt precipitates inside the outer and inner pipes is extracted from the inner pipe 22. The precipitated salt is stored in a pail 82, and the treated steam is led to the condenser 8 via pipes 73 and 66 to become fresh water.

[0029] All seawater taken into the seawater desalination and salt production plant 1 is made useful by desalination and salt production, and no processing waste is generated or discharged to the outside.

[0030] A motor 81 is provided on the piping 71, and a pail 82 for storing the produced salt is provided at the inlet 34 of the salt separator 20.

[0031] The concentrated seawater, which has been enriched by heat exchange, becomes more viscous and turns into viscous salt components. The viscous salt components are efficiently and effectively transported through the inner pipe 22 by the transport function of the screw device 23.

[0032] According to the embodiment, by providing the steam distribution device and the condenser in the seawater desalination and salt production plant 1, two steam supply and distribution systems that distribute supplied steam to the seawater desalination plant and the salt production plant are formed by pipes 67, 68 and pipe 69, and two steam collection and recovery systems that collect and recover steam derived from both the seawater desalination plant and the salt production plant in the condenser and condense the collected steam can be formed by pipes 66, 70, 71, 72, 73, and 74. This makes it possible to efficiently produce fresh water and salt without discharging desalinated seawater to the outside and without discharging any waste materials to the outside during the salt production process.

[0033] Steam supply distribution 2 systems: 1st system piping 67, 68 and 1st system piping 69 Steam collection and recovery system 2: System 1 pipes 66, 70, 72 and system 2 pipes 71, 73, 74 As described above, according to this embodiment, by providing the steam distributor and the condenser, two steam supply distribution systems can be formed, and two steam collection and recovery systems can be formed, which simplifies the steam supply system and enables fresh water and salt to be efficiently produced without discharging a portion of the treated seawater to the outside. [Explanation of symbols]

[0034] 1...seawater desalination / salt production plant, 2...seawater desalination plant, 3...salt production plant, 4...seawater tank, 5...boiler, 6...distillation tower, 7...cooling water circulation system (chiller), 8...condenser, 20...salt separator, 21...outer pipe, 22...inner pipe, 23...screw device (extrusion device), 41...steam distribution device, 66, 70, 71, 72, 73, 74...piping.

Claims

[Claim 1] A seawater desalination and salt production plant comprising a seawater desalination unit that produces fresh water from seawater, and a salt production unit that produces salt from concentrated seawater produced by the seawater desalination unit, the seawater desalination apparatus comprises a distillation column having a seawater supply source, a steam source, and a pipe through which steam from the steam source flows, and which generates steam from seawater by performing heat exchange between the seawater supplied from the seawater supply source and the steam supplied from the steam source and flowing through the pipe; a cooling water circulator; and a condenser connected to the cooling water circulator and which introduces circulating cooling water to condense the generated steam; The salt production device is composed of a double pipe of an outer pipe and an inner pipe, and steam is introduced into the space between the outer pipe and the inner pipe. A spiral extrusion device that can be rotated by a drive source is disposed inside the inner pipe. Concentrated seawater introduced from the distillation column is introduced into the inner pipe, and seawater with an increased concentration is produced as the inner pipe rotates and moves by heat exchange with the steam, and water is evaporated to produce salt. a steam distribution device connected to the steam source, forming two steam supply distribution systems that distribute the supplied steam to the seawater desalination device and the salt production device; In the seawater desalination apparatus, steam distributed from the steam distributor flows through the pipe and exchanges heat with supplied seawater to generate steam and produce fresh water; The salt production apparatus introduces steam distributed from the steam distributor into a space between the outer pipe and the inner pipe, introduces concentrated seawater introduced from the distillation column into the inside of the inner pipe, evaporates water, and produces salt; forming two steam collection and recovery systems that collect and recover steam output from both the seawater desalination plant and the salt production plant in the condenser for condensation; This seawater desalination and salt production plant is characterized by the following:

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