A kind of cold energy of liquefied natural gas is used for the device of ice making
Technical field
The utility model discloses a kind of LNG cold energy and be used for the device of ice making.
Background technology
LNG (liquid natural gas) is natural gas via depickling, processed, the cryogenic liquid mixture that the low temperature process cryogenic liquefaction forms, and its production process energy consumption is high.And the vaporization 1kg LNG of LNG receiving station need provide 830 kJ energy approximately, and promptly about 230kWh is per ton.
If can this LNG cold energy effective recycling can be saved the energy, reduces the pollution of LNG vaporescence, reduce market, downstream air feed price, improve the economic benefit of natural gas.The LNG cold energy use that begins one's study very early of Japan, the U.S., countries such as Canada, like desalinization, air separation, low-temperature grinding, ice making, generating etc.
Situation from Japanese LNG cold energy use; It is the most efficient mode of LNG cold energy use that LNG desalinizes seawater; But what LNG cold energy use technology and economic benefit were best is to be applied in the air separation industry, main because the temperature of condensing temperature that air liquefaction is required and LNG is the most approaching.Chinese patent 201010184299.2 disclosure of the Invention a kind of full-liquid air separation device that utilizes the LNG cold energy.This invention has favorable economic benefit; But system complex, and need the more nitrogen of energy compression after fractionation, because the liquefaction of nitrogen temperature is about-200 ℃; And the LNG cold energy is after flowing to pipe; Its temperature even be higher than-162 ℃ also has bigger gap from the liquefaction of nitrogen temperature, so also need bigger energy consumption.One Chinese patent application 201010141071.5 discloses a kind of backward flow type air-seperation system based on the cold energy use of LNG satellite station.Can find out from this invention; Nitrogen after the recycle air separation can be used for separation of air with the LNG cold energy, but after the fact was air separation, the nitrogen percentage composition was big; Temperature is low, but nitrogen can not liquefy all the time (its condensing temperature be lower than LNG temperature-162 ℃).So the utilization of LNG cold energy is inadequate, and more low temperature nitrogen waste is arranged.As seen from the above analysis, the LNG cold energy use is in air separation process, and equipment, process are complicated, and energy utilization efficiency is low.
Utilize the LNG cold energy generation, worldwide actually rare, and also because the temperature of LNG is-162 ℃, the cold energy quality is high, directly is used for promoting one type of TRT of turbine, and its efficient is lower, and its energy utilization efficiency is merely about 10%.Chinese patent 200720007870.7 utility models provide a kind of LNG cold energy step, integrated utilization system; Utilize liquefied natural gas (LNG) cold energy step, integratedly be used for low-temperature electricity-generating, freezer, icerink and cold water air-conditioning, and set up cold energy service company, freezer company, four construction projects of icerink company and cold water air-conditioning company.If the amount of vaporization at LNG station is restricted, equipment can not get reasonable utilization, and it is high to cause LNG cold energy cascade utilization to have equipment cost; The maintenance operation expense is high; Actually be difficult to obtain good economic benefit, even be difficult to recoup capital outlay, and be used for ice making etc. from energy utilization efficiency; The temperature coupling is all proper, and reasonable economy is arranged.
The utility model content
The utility model purpose is to overcome prior art, and having solved present LNG is directly to pass through the gasification air feed, and the cold of LNG wastes in the gasification, and the LNG cold energy is used for ice making, has then made full use of the cold energy of LNG, conserve energy.Make full use of the ice making of LNG cold energy, reach the purpose of each pipeline out temperature of control, pressure and other parameters through control piper circulatory system mass flow.
The utility model purpose realizes through following technical scheme:
A kind of cold energy of liquefied natural gas is used for the method for ice making, may further comprise the steps:
(1) 0.3~0.5MPa ,-162 ℃ liquefied natural gas and concentration are that temperature is 15~20 ℃ after 40%~55%wt, 1~2 ℃ the glycol water heat exchange; Pressure is 0.3~0.5MPa, and gasification is to get into gas distributing system behind 0.3~0.5MPa, 25 ℃ the natural gas again;
(2) the glycol water temperature after the heat exchange is reduced to-34~-36 ℃, be pressurized to 0.3~0.5MPa after, with the water heat exchange, water-setting is become ice, and ice is scraped;
(3) with hydrothermal exchange after glycol water return ethylene glycol normal temperature storage tank, it is 1~2 ℃ that glycol water in the normal temperature storage tank raises, recycle.
Implement the device of described method, comprise LNG storage tank 1, LNG gasifier 4; The cold storage tank of glycol water 5, ice machine 9, glycol water normal temperature storage tank 10, temperature sensor 14, pressure sensor 15 and a LNG air vaporizer 16; Said LNG storage tank 1 is connected with the cold logistics import of LNG gasifier 4; The cold logistics outlet of LNG gasifier 4 is connected with the import of a LNG air vaporizer 16 again; Be connected with pressure sensor 15 and temperature sensor 14 on LNG gasifier 4 and the pipeline that a LNG air vaporizer 16 is connected; The outlet of the one LNG air vaporizer 16 is connected to gas distributing system, the housing blowing air of a LNG air vaporizer 16; The hot logistics import of LNG gasifier 4 is connected with the outlet of glycol water normal temperature storage tank 10; The hot logistics outlet of LNG gasifier 4 is connected with the refrigerant import of cold storage tank 5 of glycol water and ice machine 9 successively; The refrigerant exit of ice machine 9 is connected to the import of glycol water normal temperature storage tank 10, and the running water inlet of ice machine 9 is connected with running water pipe.
Said LNG storage tank 1 is connected through hot insulated line with the 4 cold logistics imports of LNG gasifier, and hot insulated line is provided with first centrifugal pump 3, control valve 2 and flowmeter.
The cold storage tank 5 of said glycol water and ice machine 9 are connected through hot insulated line, and hot insulated line is provided with second centrifugal pump 7, control valve 8 and flowmeter.
Said LNG gasifier 4 and glycol water normal temperature storage tank 10 are connected through pipeline, are connected with the 3rd centrifugal pump 12, control valve 13 and flowmeter on the pipeline.
Said LNG storage tank 1 is storage tanks of insulation with the cold storage tank 5 of glycol water.
The liquid level of cold storage tank 5 of said glycol water and glycol water normal temperature storage tank 10 shows through liquid level gauge (6,11).
The utlity model has following advantage:
1, energy-efficient: LNG cold energy use rate is high, need not to add refrigeration power source, energy efficient during ice making;
2, stability is high; Technological process is simple, and is easy to operate, and control elasticity is bigger;
3, cost of investment is low: equipment drops into little, is easy to operation and safeguards that skidization helps the flexible utilization between the different satellite stations, reduces investment risk.
Description of drawings:
Fig. 1 puts for the skid makeup that the cold energy of liquefied natural gas of the utility model is used for ice making;
Wherein, 1 is the LNG storage tank; 2,8,13 is control valve; 3 is that first centrifugal pump, 7 is that second centrifugal pump, 12 is the 3rd centrifugal pump; 4 is the LNG gasifier; 5 is the cold storage tank of glycol water; 6 and 11 is liquid level gauge; 9 is ice machine; 10 is glycol water normal temperature storage tank; 14 is temperature sensor; 15 is pressure sensor; 16 is a LNG air vaporizer; 17 is the 2nd LNG air vaporizer.
The specific embodiment
Operation principle for better illustrative system provides three embodiment below in conjunction with Fig. 1:
Embodiment 1
A kind of cold energy of liquefied natural gas is used for the method for ice making, may further comprise the steps:
(1) 0.3~0.5MPa ,-162 ℃ liquefied natural gas and concentration are that temperature is 15 ℃ after 50%wt, 1 ℃ the glycol water heat exchange, and pressure is 0.3~0.5MPa, and gasification is to get into gas distributing system behind 0.3~0.5MPa, 25 ℃ the natural gas again;
(2) the glycol water temperature after the heat exchange is reduced to-35 ℃, be pressurized to 0.3~0.5MPa after, with the water heat exchange, water-setting is become ice, and ice is scraped;
(3) with hydrothermal exchange after glycol water return ethylene glycol normal temperature storage tank, it is 1 ℃ that glycol water in the normal temperature storage tank raises, recycle.
Said LNG storage tank 1 is connected through hot insulated line with the 4 cold logistics imports of LNG gasifier, and hot insulated line is provided with first centrifugal pump 3, control valve 2 and flowmeter.
The cold storage tank 5 of said glycol water and ice machine 9 are connected through hot insulated line, and hot insulated line is provided with second centrifugal pump 7, control valve 8 and flowmeter.
Said LNG gasifier 4 and glycol water normal temperature storage tank 10 are connected through pipeline, are connected with the 3rd centrifugal pump 12, control valve 13 and flowmeter on the pipeline.
Said LNG storage tank 1 is storage tanks of insulation with the cold storage tank 5 of glycol water.
The liquid level of cold storage tank 5 of said glycol water and glycol water normal temperature storage tank 10 shows through liquid level gauge (6,11).
Regulate control valve 2, the flow of regulating the LNG that gets into the LNG gasifier is 0.28kg/s; Regulate control valve 13, the flow of adjusting entering LNG gasifier glycol water, making the glycol water flow is 2kg/s; Regulate control valve 8, the flow of regulating the ethylene glycol that gets into ice machine is 2Kg/s;
With the water heat exchange, temperature is that 20 ℃ of water flow down with the 0.6kg/s flow along the ice machine wall, and rotating mechanism is with the 4rpm rotating speed, and scraper rotates under mechanism drives, and the ice that the heat exchange wall will be generated scrapes, and transports the ice storage tank to.Glycol water after the heat absorption flows into normal temperature storage tank 10 automatically, is warmed up to 1 ℃ naturally, per hour obtains 2 tons in ice.
Implement the device of described method, comprise LNG storage tank 1, LNG gasifier 4; The cold storage tank of glycol water 5, ice machine 9, glycol water normal temperature storage tank 10, temperature sensor 14, pressure sensor 15 and a LNG air vaporizer 16; Said LNG storage tank 1 is connected with the cold logistics import of LNG gasifier 4; The cold logistics outlet of LNG gasifier 4 is connected with the import of a LNG air vaporizer 16 again; Be connected with pressure sensor 15 and temperature sensor 14 on LNG gasifier 4 and the pipeline that a LNG air vaporizer 16 is connected; The outlet of the one LNG air vaporizer 16 is connected to gas distributing system, the housing blowing air of a LNG air vaporizer 16; The hot logistics import of LNG gasifier 4 is connected with the outlet of glycol water normal temperature storage tank 10; The hot logistics outlet of LNG gasifier 4 is connected with the refrigerant import of cold storage tank 5 of glycol water and ice machine 9 successively; The refrigerant exit of ice machine 9 is connected to the import of glycol water normal temperature storage tank 10, and the running water inlet of ice machine 9 is connected with running water pipe.
Said LNG storage tank 1 is connected through hot insulated line with the 4 cold logistics imports of LNG gasifier, and hot insulated line is provided with first centrifugal pump 3.
The cold storage tank 5 of said glycol water and ice machine 9 are connected through hot insulated line, and hot insulated line is provided with second centrifugal pump 7.
Said LNG gasifier 4 and glycol water normal temperature storage tank 10 are connected through pipeline, are connected with the 3rd centrifugal pump 12 on the pipeline.
Said LNG storage tank 1 is storage tanks of insulation with the cold storage tank 5 of glycol water.
The utility model method has two kinds of embodiments; A kind of is that LNG in the LNG storage tank 1 is through after the supercharging; A part directly gets into the 2nd LNG air vaporizer 17, and gasification is to get into gas distributing system behind 0.3~0.5MPa, 25 ℃ the natural gas, and remainder entering LNG gasifier 4 is used for ice making.Another kind is all to get into LNG gasifier 4 to be used for ice making.
Embodiment 2
The low-temp low-pressure LNG that from LNG storage tank 1, comes out is pressurized to 0.3-0.5MPa through first centrifugal pump 3, and LNG after the pressurization flows into LNG vaporizer 4, with glycol water after 10 superchargings of glycol water normal temperature storage tank in 4 li heat exchange of vaporizer.With reference to the pressure sensor 15 of LNG pipeline, temperature sensor 14, the flow of adjustment LNG guarantees that flow is 0.15kg/s; The flow of glycol water is 1kg/s, and the LNG outlet temperature is 17 ℃, and pressure is 0.3-0.5MPa; Gasification is to get into gas distributing system behind 0.3~0.5MPa, 25 ℃ the natural gas again, and the glycol water after the cooling flows into the cold storage tank 5 of glycol water, through second centrifugal pump 7; Flow is 1kg/s, and pressure is elevated to 0.3-0.5MPa, gets into ice machine 9.Temperature is that 20 ℃ of water flow down with the 0.32kg/s flow along the ice machine wall, and rotating mechanism is with the 3rpm rotating speed, and scraper rotates under mechanism drives, and the ice that the heat exchange wall will be generated scrapes, and transports the ice storage tank to.Glycol water after the heat absorption flows into glycol water normal temperature storage tank 10 automatically, is warmed up to 1 ℃ naturally, obtains per hour to obtain 1.1 tons in ice.
Embodiment 3
The low-temp low-pressure LNG that from LNG storage tank 1, comes out is pressurized to 0.3-0.4MPa through first centrifugal pump 3, and LNG after the pressurization flows into LNG vaporizer 4, with glycol water after 10 superchargings of glycol water normal temperature storage tank in 4 li heat exchange of vaporizer.With reference to the pressure sensor 15 of LNG pipeline, temperature sensor 14, adjustment LNG flow guarantees that flow is 0.1kg/s; The flow of glycol water is 0.7 kg/s, and the LNG outlet temperature is 20 ℃, and pressure is 0.3-0.5MPa; Gasification is to get into gas distributing system behind 0.3~0.5MPa, 25 ℃ the natural gas again, and the glycol water after the cooling flows into cold storage tank 5, through second centrifugal pump 7; Flow is 0.7Kg/s, and pressure is elevated to 0.3-0.5MPa, gets into ice machine 9.. temperature is that 20 ℃ of water flow down with the 0.22Kg/s flow along the ice machine wall, and rotating mechanism is with the 2rpm rotating speed, and scraper rotates under mechanism drives, and the ice that the heat exchange wall will be generated scrapes, and transports the ice storage tank to.Glycol water after the heat absorption flows into glycol water normal temperature storage tank 10 automatically, is warmed up to 1 ℃ naturally, per hour obtains 0.88 ton in ice.
Get LNG flow 1000kg/h, system's gross investment about 900,000 is produced 1.5t ice according to the 1tLNG gasification and is calculated, according to about 200 yuan in ice per ton, and the about 80kWh of ice power consumption per ton.Calculate by 0.8 yuan/kWh of general electricity price and 0.45 yuan/kWh of time-of-use tariffs at night (8 hours), every day, energy-saving efficiency was about 1968 yuan, and a year benefit reaches 720,000 yuan.The annual ice of selling can earn a profit 2,600,000 yuan.