KR20180011903A - Multi stage fresh water generator for offshore - Google Patents

Abstract

The present invention relates to an apparatus for preparing fresh water by eliminating salt from salt-containing water such as sea water, and more specifically, to a multi-step apparatus for preparing fresh water for offshore, wherein energy can be saved by using a multi-step evaporation manner where waste heat energy is recovered and then reused to save energy. The multi-step apparatus for preparing fresh water for offshore according to the present invention is an apparatus for preparing fresh water, where sea water is vaporized and condensed to prepare fresh water. The apparatus for preparing fresh water comprises a first fresh water generator (300) and a second fresh water generator (400), wherein the second fresh water generator (400) reuses heat of vaporization of the sea water vaporized in the first fresh water generator (300) to prepare fresh water. In addition, the second fresh water generator (400) includes: a first heat exchanger (210) where the sea water stored in the sea water storage tank (100) is primarily supplied with heat from the sea water vaporized in the first fresh water generator (300); and a second heat exchanger (220) where the sea water passed through the first heat exchanger (210) is secondarily supplied with heat from the sea water vaporized in the first fresh water generator (300), and the first fresh water generator (300) includes: a first vaporizer (310) supplying heat to the sea water introduced from the second heat exchanger (220); and a first demister (321) eliminating salt from the vapor supplied with heat by the first vaporizer (310).

Description

[0001] MULTI STAGE FRESH WATER GENERATOR FOR OFFSHORE [0002]

The present invention relates to a fresh water producing apparatus for producing fresh water from which salt is removed from saline-containing water, such as seawater, and more particularly, to a fresh water producing apparatus capable of saving energy by using a multistage evaporation type in which waste heat energy is recovered and reused It is a multi-stage fresh water production device for offshore.

Methods for making seawater fresh water include reverse osmosis, freezing and evaporation. The fresh water production system using the reverse osmosis method has a complicated structure, is expensive to manufacture, and needs frequent replacement of the filter. Since the freezing method is performed at a low temperature, it is necessary to shut off the outside and heat, and it is difficult to separate seawater adhered to ice. Therefore, a fresh water producing device using a simple evaporator and a simple and economical evaporator is widely used. According to the evaporation method, by heating the seawater, the water except the salt is changed into the steam, and the steam is condensed to make fresh water.

Since the fresh water producing apparatus consumes a lot of electric power, there is a need for a fresh water producing apparatus capable of saving energy. In particular, the offshore facility requires a customized facility suited for the purpose of enduring a complicated and rough external environment However, research and development on this subject are insignificant.

The fresh water producing apparatus designed to save current energy is a fresh water producing apparatus using solar energy (Korean Patent Laid-Open No. 10-2010-0102902). The solar water photovoltaic module comprises a solar photovoltaic module for absorbing solar heat to generate electric energy; A power storage device for storing electric energy generated by the solar photovoltaic module; And is unsuitable for offshore installation in rough sea environments.

In addition, there are a lot of excellent companies in the offshore manufacturing industry in the world, but design, inspection, supervision and equipment depend on foreign technology, so it is difficult to solve the technical issues when problems are found during trial operation. The cost was exhausted.

In particular, existing reverse osmosis type clean water production system consumes a lot of electric energy and can not utilize waste heat, resulting in low efficiency. Specifically, there is a problem in that equipment costs such as a high-pressure pump and a membrane are high, and a high-pressure pump is used, resulting in high power consumption and high operation cost. In addition, it is very expensive to replace the reverse osmosis membrane, and it is difficult to check the problem of the entire system in real time when diagnosing the equipment. In addition, boron is detected and there is a problem in durability in the film, and there is a problem that pretreatment of the supply seawater is required.

Korean Patent Publication No. 10-2010-0102902

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an apparatus for manufacturing an offshore fresh water capable of saving energy.

It is another object of the present invention to provide an offshore fresh water producing apparatus in which load fluctuations of a generator engine are solved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention as set forth in the accompanying drawings. It will be possible.

The apparatus for producing an offshore multi-stage fresh water according to the present invention is a device for producing fresh water by vaporizing seawater and condensing the seawater, the fresh water producing apparatus comprising a first fresh water producing unit (300) The second fresh water producing unit 400 is a multi-stage fresh water producing apparatus for offshore, which produces fresh water by reusing the heat of vaporization of the seawater vaporized in the first fresh water producing unit 300.

The second fresh water generation unit 400 may further include a second fresh water generation unit 400 for generating the fresh water from the seawater stored in the seawater storage tank 100 through a first heat exchanger (210); And a second heat exchanger (220) in which the seawater having passed through the first heat exchanger (210) is secondarily supplied with heat from seawater vaporized in the first fresh water generator (300)

The first fresh water generation unit 300 includes a first vaporization unit 310 for supplying heat to the seawater introduced from the second heat exchanger 220; And a first demister (321) for removing the salt of the steam supplied from the first vaporizer (310).

The second fresh water generator 400 condenses a part of the steam introduced from the first evaporator 310 of the first fresh water generator 300 and transfers the condensed fresh water to the fresh water storage tank 500 A second vaporizing unit 410 for discharging the vaporized gas; A second vapor chamber 420 for exchanging heat between the steam introduced from the second vaporization unit 410 and the seawater introduced from the seawater storage tank 100; A fresh water condensation tank 422 in which vapor introduced into the second vapor chamber 420 is condensed after heat exchange to produce fresh water; And a second demister (421) for removing the salt of the steam introduced from the second vaporization unit (410).

According to the solution of the above-mentioned problems, the present invention has energy saving effect by recovering the waste heat by applying the low pressure evaporation type.

In addition, the use of a low-capacity seawater pump reduces the initial investment and operating costs by saving energy.

Further, the efficiency of the fresh water producing apparatus is increased by the high-efficiency water ejector, and the piping size of the pump can be reduced.

In addition, there is an effect of solving the load fluctuation of the generator engine by controlling the flow rate per load in real time.

In addition, there is an effect that the operation state and the abnormality can be grasped in real time through the monitoring system of the fresh water manufacturing apparatus.

1 is a perspective view of an apparatus for producing an offshore multi-
Fig. 2 is a schematic diagram of a multi-stage fresh water producing apparatus for offshore.

The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent by reference to an embodiment which will be described in detail below with reference to the accompanying drawings.

The present invention relates to a fresh water producing apparatus for producing fresh water from which salt is removed from saline-containing water, such as seawater, and more particularly, to a fresh water producing apparatus capable of saving energy by using a multistage evaporation type in which waste heat energy is recovered and reused It is a multi-stage fresh water production device for offshore.

Hereinafter, the structure of the above-described offshore multi-stage fresh water producing apparatus will be described in detail with reference to the drawings.

3, the offshore multi-stage fresh water producing apparatus includes a seawater storage tank 100, a water ejector 200, a first fresh water generating unit 300, a second fresh water generating unit 400, (500), a steam boiler (600), and a cooling tower (700).

1, the first fresh water generator 300 includes a first vaporizer 310 and a first vapor chamber 320, and the second fresh water generator 400 includes a second vaporizer 320, And includes a vaporization unit 410 and a second vapor chamber 420.

3, a description will be made of a process of cleansing the seawater by an offshore multi-stage fresh water producing apparatus according to the present invention.

First, the seawater stored in the seawater storage tank 100 is introduced into the second vaporization unit 410 of the second fresh water generation unit 400 by the pressure of the water ejector 200. The seawater flowing into the second vaporization unit 410 is heat-exchanged with the seawater flowing into the second vaporization unit 410 from the first vapor chamber 320 of the first fresh water generation unit 300 and is vaporized. Some of the vaporized vapor in the second vapor chamber 420 flows into the first vaporizing unit 310 and the remaining vapor enters the second vaporizing unit 410. The steam introduced into the first heating unit is supplied to the second vaporizing unit 410 after being supplied heat to the first steam chamber 320 by the steam boiler. The steam introduced into the second vaporization unit 410 is heat-exchanged with the seawater introduced from the seawater storage tank 100, condensed and stored in the fresh water storage tank 500.

More specifically, each device will be described in detail below.

First, the seawater storage tank 100 is a tank for storing seawater before being introduced into the fresh water system. The seawater stored in the seawater storage tank 100 flows into the second fresh water generator 400.

Next, the water ejector 200 is a pressure device for introducing the seawater stored in the seawater storage tank 100 into the second fresh water generator 400.

The seawater is preferably introduced at a rate of 25,000 kg / hr by the water ejector 200 and at a rate of 3 kg / cm ² at 32 ° C.

The water ejector 200 has a maximum back pressure of 1.0 kg / cm ^{2. In} general, the water ejector 200 used in the fresh water producing apparatus is not applicable to large offshore vessels and super large vessels. However, the water ejector 200 can be used for a large offshore, an ultra-large crude oil carrier, a super large ore carrier, and a very large solid water line, and is provided in the multi-stage fresh water producing apparatus manufactured by the present invention.

Next, the seawater discharged from the seawater storage tank 100 flows into the first heat exchanger 210. The first heat exchanger 210 is a heat exchanger that flows into the second vapor chamber 420 of the second fresh water generator 400. A portion of the seawater that has absorbed heat in the first heat exchanger 210 flows into the second heat exchanger 220 and the remainder enters the cooling tower 700.

The seawater of the first heat exchanger 210 absorbs heat by the steam flowing out of the first fresh water generator 300 and the steam introduced into the second heat exchanger 220 is discharged through the first fresh water generator And the heat is reabsorbed by the steam flowing out from the unit (300).

The steam exiting the second heat exchanger 220 is preferably discharged at a flow rate of 1,375 kg / hr and a temperature of 35.4 ° C.

In addition, it is preferable that the steam which can not flow into the second heat exchanger 220 flows into the cooling tower 700 and flows at a flow rate of 23,625 kg / hr and a temperature of 35.4 ° C. The steam flowing into the cooling tower 700 is condensed and then flows into the seawater storage tank 100 again.

Next, a portion of the steam flowing out of the second heat exchanger 220 flows into the first fresh water generator 300, and the rest of the steam flows into the second fresh water generator 400.

The first fresh water generator 300 includes a first vaporizer 310 and a first chamber and the vapor discharged from the second heat exchanger 220 flows into the first vaporizer 310. When entering the first vaporization unit 310, it is preferable that the vapor is introduced at a flow rate of 687.5 kg / hr and a temperature of 35.4 ° C.

The steam introduced into the first vaporization unit 310 is absorbed by the third heat exchanger 310 connected to the steam boiler 600. The steam passing through the first vaporizing unit 310 is discharged at a temperature of 51.5 ° C. and a pressure of 660 mmHg and a part of the steam is introduced into the first vapor chamber 320, The second vaporizing portion 410 of the second vaporizing portion 410.

A portion of the steam that has passed through the first vaporizer 310 and flows into the first vapor chamber 320 is discharged to the second vaporizer 410 after the salt is removed by the first demister 321 Flows at a flow rate of 233.5 kg / hr and a temperature of 51.5 ° C.

Specifically, the first demister 321 removes salt in the steam. When the vaporization rate of the vapor evaporated in the first vaporization unit 310 is fast, the salt in the seawater can be included in the vapor and can be moved. Therefore, in order to remove the fine salt contained in the vapor having a high velocity, 1 < / RTI >

In addition, the remaining steam passing through the first vaporizing unit 310 and flowing into the second vaporizing unit 410 flows at a flow rate of 591.5 kg / hr.

The steam not flowing into the first fresh water generator 300 from the second heat exchanger 220 flows into the second vaporizer 410 of the second fresh water generator 400. The steam flowing into the second vaporization part 410 is preferably introduced at a flow rate of 687.5 kg / hr and a temperature of 35.4 ° C.

Next, the second fresh water generator 400 includes a second vaporizer 410 and a second vapor chamber 420.

First, steam is introduced into the second evaporator 410 from the second heat exchanger 220, the first vaporizer 310, and the first vapor chamber 320. The steam flowing in the second heat exchanger 220 flows into the first vaporizing unit 310 and the steam flowing in the first vaporizing chamber 320 flows into the second heat exchanging unit Lt; RTI ID = 0.0 > (220). ≪ / RTI > At this time, some condensed fresh water flows into the fresh water storage tank 500, and some of the condensed steam flows into the second vapor chamber 420. The fresh water condensed in the second vaporization part 410 and flowing into the fresh water storage tank 500 is preferably introduced at 4.604 ton / day.

The steam entering the second vapor chamber 420 flows at a temperature of 38.5 DEG C and a pressure of 710.49 mmHg. At this time, the steam flowing into the second steam chamber 420 is desalted by the second demister 421. The second demister 421 removes the fine salinity of the steam in the same manner as the first demister 321.

The steam flowing into the second steam chamber 420 is discharged to the first heat exchanger 210 and the second heat exchanger 220 as described above, 420 are condensed and condensed in the fresh water condensation tank 422. The fresh water condensed in the fresh water condensation tank 422 is stored in the fresh water storage tank 500 at 5.396 ton / day.

Next, the steam boiler 600 is connected to the third heat exchanger 310, and the third heat exchanger 310 provides heat to the first vaporizer 310 .

The third heat exchanger 310 preferably flows into the first vaporizer 310 at a temperature of 80 ° C. and provides heat to the first vaporizer 310 and flows out at a temperature of 64.0 ° C.

The multi-stage fresh water producing apparatus manufactured by the present invention is equipped with a monitoring system to control the flow rate, temperature and pressure of each rod in real time so that it can check the real time operation state and the abnormality.

Hereinafter, the superiority of the present invention will be described by comparing the multi-stage fresh water producing apparatus manufactured by the present invention with the conventionally used reverse osmosis type fresh water producing apparatus and comparing power consumption.

First, we will look at the performance and localization rate of offshore equipment.

briefs Localization rate Remarks 1. Machinery 15-20% - Most machinery imports
- Simple production equipment such as water tube and heat exchanger Localization 2. Piping material 15-20% - Localization of bulk material and general valve
- High pressure and special material valves are imported
- Imported total control valve and shutdown valve for instrumentation valve. 3. Electric device
35 to 45% - Most of the electrical panel imports
- Most of motor motors are also imported.
- Bulk material such as cable tray is localized 4. Instrumentation equipment 10 to 15% - Import of most instrumentation equipment
- Localizing only Bulk Material such as Tubing and Tube Fitting 5. Safety equipment About 5% - Most safety equipment imports

As shown in Table 1, in the case of machinery, piping, and instrumentation equipment, most of the special fields except for the simple production equipment depend on imports, and in the case of safety equipment, the localization rate Was about 5%.

In this situation, offshore equipments have difficulty in transportation and problem solving, and it is obvious that development of offshore water production equipment is urgent.

Next, the advantages and disadvantages of the reverse osmosis system and the multi-stage evaporative fresh water production apparatus of the present invention will be compared below.

Previous product (reverse osmosis) Classification Technological developments (multi-stage evaporation) Electrical energy Heat source Waste heat (M / EorG / E) Waste heat (M / EorG / E) waste Energy recovery Booster pump, MF control valve, chemical injector, MF module, consumption and cleaning tank Major equipment Evaporator, condenser, vapor chamber, ejector Distill pump Equipment cost expensive
(High pressure pump, membrane etc.) Initial investment cost Low cost of equipment High power consumption (use high pressure pump) Driving costs Low power consumption High cost when replacing reverse osmosis membrane Maintenance cost Low cost when replacing consumables such as gaskets and tubes Possible to identify the problem of the equipment itself rather than the entire system Equipment diagnosis Enables real-time problem identification for the entire system Equipment is small Advantages Energy saving (G / E waste heat recovery), easy operation Lower initial investment costs Boron detection Disadvantages Membrane durability issues Requires pretreatment of supply seawater

As shown in Table 2, since the present invention uses recycled waste heat energy, the initial investment cost is low because of low power consumption and low equipment cost. In addition, since the high-pressure pump is not used, the replacement cost for consumables is low. In addition, since it is possible to identify problems in real time in the entire system, it is easy to diagnose the equipment.

Next, we will compare the technology of the present invention with the plate type, the tubular type, and the domestic fresh water production apparatus.

Item Conventional technology Development technology Characteristic Plate Type Tubular Type Domestic technology (Alfa Laval, Sweden) (Japan, Sasakura) (DongHwa) Heat consumption 300 kW 282 kW 282 to 310 kW 197 kW Saving Rate:
Up to 30% Flow rate (H / M) 22 m ³ / hr 26 m ³ / hr 24 m ³ / hr 15 m ³ / hr Pump Specifications
minimization generator 2 Sets 2 Sets 2 Sets 1 Set Saving:
G / E Fuel Oil Pump power
Consumption - - - HzControl Saving Rate:
Up to 10% with Inverter Suppress Scale Generation

Compared with the prior art, when the heat consumption is checked, it can be seen that the multi-stage fresh water producing apparatus according to the present invention can save about 70% of the heat and reuse the heat up to about 30%. Therefore, it can be seen that the number of generators can be reduced to 1, and the power consumption of the pump can also be reduced by 10%.

Next, the difference in power consumption when using the fresh water producing apparatus manufactured by the present invention when using the reverse osmosis type fresh water producing apparatus according to the prior art and the saving cost are shown.

Classification Reverse Osmosis Type OperatingCost Technical development product project "Stena" DrillShip (90ton / day): 30ton / day * Based on 3Sets Operating period About 365 Days - Required manpower 180 persons - Pump Specifications 63 liter / min x 60 bar 40 m ³ / hr x 3.0 bar Q'ty of Motor 55 kW x 1 Sets 11 kW x 3 Sets Power consumption per day 55 kW x 1 sets x 24 hr = 1,320 kW 11 kW x 3 sets x 24 hr = 792 kW Power consumption (per year) 1,320 x 365 = 481,800 kW 792 x 365 = 289,080 kW Fuel Consumption (per year, liter) (481,800 kW x 182 g / kW-h / 0.835 kg / liter) / 1000 = 105,015 liter = 105 ton (289,080 kW x 182 g / kW-h / 0.835 kg / liter) / 1000 = 63,009 liter = 63 ton Fuel Consumption (per year, bbl) 105,015 liter / 158.9 liter / bbl = 660 bbl 63,009 liter / 158.9 liter / bbl = 397 bbl (1 bbl = 158.9 liters) (1 bbl = 158.9 liters) Fuel cost (USD $ 92/1 bbl) 660 bbl x $ 92 = $ 60,720 397 bbl x $ 92 = $ 36,524 Power savings (toe / year) (481,800289,080) x 0.00022 = 42.4 toe Annual savings $ 60,720 - $ 36,524 = $ 24,196 * Equipment
01. Generator Engine: 12V 32/40
02. SFOC: 182 g / kW-h
03. Fuel Cost: Based on WTI (Western Texas), Sep 25

As shown in Table 4, the daily power consumption of the reverse osmosis system is 1,320 kw, and the multi-stage fresh water producing apparatus manufactured by the present invention has 792 kw. Accordingly, the annual power consumption is 481,800 kw for the reverse osmosis system and 289,080 kw for the multi-stage fresh water production apparatus manufactured by the present invention.

In terms of fuel consumption, the cost of the reverse osmosis system is about 60,720 dollars per year, and the cost for the multi-stage water purification system of the present invention is 36,524 dollars a year, so that the annual saving cost is 24,196 dollars.

Finally, the effect of the present invention will be described below through comparison between the present invention described above and the prior art.

Technical aspects Lower initial investment and operating costs Use relatively inexpensive materials Using low-capacity seawater pumps Energy saving Multi-stage recycling
: The steam of the first fresh water generation part 300 is reused as the heat source of the second fresh water generation part 400 Resolving generator load fluctuations Adjust the cylinder coolant flow rate according to temperature
: Motor Hz control via the Inverter High-Efficiency Water Ejector Maximum Back Pressure 1.0kg / cm ² Development
: Increased efficiency and reduced pump piping size economical,
Industrial aspect Cost Reduction PlateType: Titanium and stainless steel Reverse Osmosis Type (ROType): High Pressure Pump and Membrane Filter  Multi-stage water purification type: General carbon steel (Rubber Coating) and aluminum-copper pipe Social aspect Contributing to national industrial development Entering Offshore with foreign equipments
: Expected to create new revenue by pioneering new markets

As shown in Table 5, titanium and stainless steel pipes are used for the plate type, and costs and maintenance costs for the fresh water producing device are increased because the reverse osmosis uses a high-pressure pump and a membrane filter.

However, as shown in Table 5, the multi-stage fresh water producing apparatus manufactured according to the present invention can be roughly divided into the technical aspect, the economic industrial aspect, and the social aspect.

First, the technical aspect reduces initial investment and operating costs. Costs can be saved by using relatively inexpensive materials and by using an applied amount of seawater pumps. Also, since the steam of the first fresh water generator 300 is reused as a heat source of the second fresh water generator 400, energy can be saved. Also, the load fluctuation of the generator can be solved by adjusting the flow rate of the cylinder cooling water according to the temperature. In addition, since the back pressure of the water ejector 200 is 1.0 kg / cm ² , the efficiency can be increased and the size of the pump piping can be reduced.

Next, economic and industrial aspects can reduce costs. The multi-stage fresh water producing apparatus manufactured by the present invention uses a general carbon steel and an aluminum-copper pipe, so that the cost can be reduced.

Next, it can contribute to national industrial development. The company can enter the offshore field, where foreign equipments are currently dominant, and generate new profits by pioneering new markets.

As described above, it is to be understood that the technical structure of the present invention can be embodied in other specific forms without departing from the spirit and essential characteristics of the present invention.

Therefore, it should be understood that the above-described embodiments are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, All changes or modifications that come within the scope of the equivalent concept are to be construed as being included within the scope of the present invention.

100. Seawater storage tank
200. Water ejector
210. First heat exchanger 220. Second heat exchanger
300. The first fresh water generation unit
310. First vaporizer 320. First vapor chamber
321. First Demister
400. The second fresh water generating unit
410. Second vaporizer 420. Second vapor chamber
421. 2nd Demister 422. Fresh water condensation tank
500. Fresh water storage tank
600. Steam boiler
610. Third Heat Exchanger
700. Cooling Tower

Claims (5)

A fresh water producing device for producing seawater by vaporizing seawater and condensing it,
The fresh water producing apparatus includes a first fresh water producing unit 300 and a second fresh water producing unit 400,
The second fresh water generation unit 400 includes an offshore multi-stage fresh water production apparatus 300 for producing fresh water by reusing vaporization heat of the seawater vaporized in the first fresh water generation unit 300, The method according to claim 1,
The second clear water generation unit (400)
A first heat exchanger (210) in which the seawater stored in the seawater storage tank (100) is firstly supplied with heat from seawater vaporized in the first fresh water generator (300);
And a second heat exchanger (220) in which the seawater having passed through the first heat exchanger (210) is secondarily supplied with heat from the seawater vaporized in the first fresh water generator (300). Device 4. The method according to any one of claims 1 to 3,
The first fresh water generation unit 300 includes:
A first vaporizer 310 for supplying heat to the seawater introduced from the second heat exchanger 220;
A first demister 321 for removing the salt of the steam supplied from the first vaporizer 310;
And a first steam chamfer for discharging the depleted vapors from the first demister (321) to the second fresh water generator (400). The offshore multi- 4. The method according to any one of claims 1 to 3,
The second clear water generation unit (400)
A portion of the steam introduced from the first vaporization unit 310 of the first fresh water generation unit 300 is condensed,
A second evaporator 410 for discharging the condensed fresh water to the fresh water storage tank 500;
A second vapor chamber 420 for exchanging heat between the steam introduced from the second vaporization unit 410 and the seawater introduced from the seawater storage tank 100;
A fresh water condensation tank 422 in which vapor introduced into the second vapor chamber 420 is condensed after heat exchange to produce fresh water;
And a second demister (421) for removing the salt of the steam introduced from the second vaporization unit (410) The method according to claim 1,
The multi-stage water is for the second comprising a water ejector 200 to move to the fresh water generator 400, an off-the water ejector 200 has a maximum back pressure 1.0kg / cm ² Shore water storage tank 100 Fresh water manufacturing equipment

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