A kind of efficient integrated sea water desalinating plant of MVR and method for desalting seawater
Technical field
The present invention relates to a kind of device and method utilizing mechanical vapor recompression technology to carry out sea water desaltination.
Background technology
China is populous, and Freshwater resources are increasingly in short supply, and development desalination technology has great importance to the scarcity solving Freshwater resources.Desalination technology based on method of evaporating has the advantage such as product water water quality, cost that the method such as membrane sepn, ion-exchange does not have.But traditional single-action and multiple-effect evaporation technology need to provide a large amount of raw steam, and need configure coal firing boiler and cooling system, the energy consumption that is difficult to avoid can be caused and produce a large amount of waste discharges.Cause overall system architecture complicated, bulky, operation and maintenance difficulty, running cost sharply rises simultaneously.
Function of mechanical steam recompression is a kind of evaporation technology, is called for short MVR (Mechanical Vapor Recompression).Refer in evaporation, by secondary steam adiabatic compression, a kind of way that the heating chamber being sent into vaporizer is subsequently reused as thermal source.Secondary steam after compression temperature of saturation raises, and forms enough heat transfer temperature differences, therefore again can be used as termite with boiling liquid in device.Therefore need only supplement a certain amount of compression work, just can utilize a large amount of latent heat of secondary steam.MVR method does not need outside thermal source, and the energy consumption of system is only the energy consumption of compressor and all kinds of pump, so energy-saving effect is quite remarkable.Cause overall system architecture simple simultaneously, take up an area volume little, operation and maintenance is simple, has considerable economic benefit.
Also have a large amount of chlorions in seawater, at high temperature can cause serious corrosion to equipment.In addition, the equipment thermosteresis of cold operation is lower, can save a large amount of energy.Therefore, low-temp low-pressure sea water desaltination side has significant advantage.
According to retrieving the patent information obtained at present, Chinese invention patent 201110104604.7,201010300875.5 and 200910138238.X, CN101591042A etc. all provide solar heat compression MVR sea water desalinating plant, but these patents all do not process the solution gas in seawater.The waste heat of 201010300875.5 pairs of strong brines and product fresh water does not also reclaim, and causes the significant wastage of the energy.In addition, these patents all need there is harsh requirement to Working environment, equipment and equipment complexity, for patent 200910138238.X, whole plant is made up of large number quipments such as solar energy collector, steam injector, compressor, heating chamber, vaporizer, interchanger, and complex structure and floor space senior general limit the use of these techniques.
The technical scheme of the MVR sea water desalinating plant that Chinese invention patent 20031010755.7 is announced is the prolong, sprinkling system, fresh-water tank and the foam removal net that comprise steam mechanical compressor, multiple vaporizer and be placed in vaporizer, the outlet of steam mechanical compressor is connected with the prolong in the first single-effect evaporator in multiple vaporizer, prolong is connected with fresh-water tank, the vapour outlet of the first single-effect evaporator is connected with the prolong in lower 1st effective evaporator, class is pushed into the last single-effect evaporator, and multiple vaporizer realizes multiple-effect stepped evaporation.This complex process equipment, and the waste heat that system produces is not reclaimed.
To sum up, there is many deficiencies in current technology, at process aspect, do not consider the operational condition of sea water desaltination, and the heat transfer that non-condensable gas causes hinders; In addition, because a large amount of sea water desalinating plants is mounted in the large island of day and night temperature, outdoor, existing patent also reckons without the operation stability of desalination system; In device, there is not patent to propose integrated concept, be unfavorable for installing and using in the place of ship, limited floor space, and the pre-treatment to seawater of traditional technique is carried out in settling tank, cannot realize integrated.
Summary of the invention
Technical problem to be solved by this invention overcomes the deficiencies in the prior art, the integrated sea water desalinating plant of efficient MVR providing a kind of energy consumption low, stable.
The method for desalting seawater that the present invention provides a kind of energy consumption low, stable, easy to operate simultaneously.
For overcoming the above problems, a kind of technical scheme that the present invention takes is as follows:
A kind of efficient integrated sea water desalinating plant of MVR, it comprises mainframe, be arranged on the pre-processing module in mainframe, heating and waste heat recovery module, function of mechanical steam recompression module and PLC control cabinet, be arranged on the evaporation module outside mainframe, and connecting tube;
Pre-processing module comprise be communicated with seawater feed-pipe from backwash filter, in seawater feed-pipe, add the chemicals dosing plant of medicament needed for pre-treatment, the seawater after filtering be divided into the three-way pilot valve on two tunnels;
Heating and waste heat recovery module comprise with the water side of three-way pilot valve respectively by the condensation fresh water heat exchanger of pipeline communication and strong brine interchanger, and the seawater after heat exchanging carries out degassed de-gassing vessel, and for storing the fresh water tank of condensation fresh water;
Evaporation module comprises vaporizer, for removing the scum dredger of the foam carried secretly in the steam that produced by vaporizer;
Function of mechanical steam recompression module comprises Mechanical Vapor Compression;
Connecting tube comprises the seawater pipeline that two ends are communicated with vaporizer with de-gassing vessel respectively, the condensation fresh water production water pipe that two ends are communicated with condensation fresh water heat exchanger with vaporizer respectively, the strong brine vent pipe that two ends are communicated with strong brine interchanger with vaporizer respectively, the strong brine circulation tube that two ends are communicated with strong brine vent pipe with seawater pipeline respectively;
Described each module is all connected with PLC control cabinet and controlled.
Further, mainframe is rectangular parallelepiped, and comprise inner frame and be removably disposed in the panel on inner frame, panel built-in heat insulation material layer, is provided with sprayed coating outside panel, panel offers ventilation hole.
Further, the parts in described mainframe take piecemeal decoration form, and pre-processing module, heating and waste heat recovery module, function of mechanical steam recompression module and PLC control cabinet are set to one piece respectively.
Preferably, described condensation fresh water heat exchanger, strong brine interchanger are plate-type heat exchanger.
Preferably, described pre-processing module also comprises and being connected and in check flow detection device, water temperature test set and Turbidity measurement equipment with PLC control cabinet.
Preferably, described de-gassing vessel comprises vacuum degassing tower.
Preferably, described vaporizer is combined-type evaporator, and the evaporation cavity for evaporation of seawater of this combined-type evaporator and the condensation chamber for vapor condensation are combined in an equipment.This vaporizer can reduce the energy consumption that heat dissipation brings, and is conducted heat by the tube wall of heat-transfer pipe, heat transfer temperature difference can be reduced, and reduces the energy consumption of whole system.
Preferably, pressure checking device, water temperature test set and brine concentration test set are installed in described vaporizer.
Preferably, described compressor is variable frequency control compressor, and is equipped with temperature and pressure test set.
Preferably, the described connecting tube water cycle also comprised for being produced by scum dredger returns the recovery tube of vaporizer.
Further, the one-way control valve that the pipeline that pre-processing module is also included between seawater chemicals dosing plant and seawater feed-pipe is arranged.
Further, evaporate module and also comprise the one-way control valve be arranged on strong brine circulation tube.
The another technical scheme that the present invention takes is:
Utilize the integrated sea water desalinating plant of above-mentioned efficient MVR to carry out a method for sea water desaltination, it comprises the steps:
(1) sea water preprocessing: charging seawater is passed into and filters from backwash filter;
(2) seawater preheating: the seawater after reflexive washed frit is divided into two tunnels by three-way pilot valve, carries out preheating respectively through condensation fresh water heat exchanger and strong brine interchanger, makes seawater reach evaporation temperature required;
(3) degassed: the seawater after preheating enters de-gassing vessel, remove room temperature incondensable gas;
(4) evaporate: the seawater after degassed enters vaporizer together with the strong brine looped back, and seawater evaporates in vaporizer, evaporation is carried out under negative pressure, and the vaporization of part seawater forms water vapor, and remaining seawater forms bittern;
(5) vapor recompression: the water vapor that seawater vaporization is formed enters mechanical vapor compressor and compresses after scum dredger foam removal, the steam that after compression, temperature and pressure improves enters into vaporizer, in evaporator room, after release of heat, condensation forms condensation fresh water, the condensation fresh water produced enters in condensation fresh water heat exchanger with after charging seawater to make heat exchange delivers to fresh water tank, the water that foam removal produces enters seawater pipeline by recovery tube, sends in vaporizer together with seawater;
(6) part circulation of the strong brine of evaporation generation, with sea water mixing, enter into vaporizer, remainder is passed in strong brine interchanger and carries out heat exchange with charging seawater.
According to the present invention, according to the practical situation of seawater, in charging seawater, add medicament optionally through chemicals dosing plant and seawater is processed.Medicament is generally flocculation agent, Scale inhibitors, sterilant etc.
Preferably, in step (4), the working pressure of vaporizer is 9.6KPa ~ 84.5KPa, and vaporization temperature is 45 DEG C-95 DEG C.
Preferably, the temperature entering the condensation fresh water of condensation fresh water heat exchanger in step (2) is 60 ~ 100 DEG C, and the temperature entering the strong brine of strong brine interchanger is 45 ~ 95 DEG C.
Preferably, through condensation fresh water heat exchanger seawater be 1:0.8 ~ 1.2 through the throughput ratio of the seawater of strong brine interchanger.
Preferably, in step (6), loop back 5% ~ 30% of the strong brine produced in vaporizer.More preferably, loop back 8% ~ 15% of the strong brine produced in vaporizer.Will loop back vaporizer strong brine and degassed after sea water mixing after, pass into together in vaporizer.More preferably, by strong brine recycle pump, strong brine is squeezed in seawater feed pipe, and the pump line that circulated by strong brine is communicated with strong brine vent pipe, is carried out the amount of controlled circulation strong brine by the flow controlling strong brine recycle pump.
Due to the employing of above technical scheme, the present invention compared with prior art has following advantage:
1, the present invention is integrated device, facility compact, and volume is little, and assembly precision is high, can process according to module, can carry out, in-site installation and convenient disassembly when safeguarding according to function piecemeal;
2, the present invention adopts and replaces traditional settling tank to filter seawater from backwash filter, solve the deficiency that conventional apparatus cannot be integrated, meanwhile, substantially reduce pretreatment time, timing automatic can close cleaning from backwash filter, decrease and safeguard and shut down the impact brought;
3, be dissolved with the gas of certain ratio in seawater, these gases, when temperature raises and sea water salinity increases, can be separated out gradually, be mixed in steam.When steam is when evaporator room is as heating medium condensation, these steam can not condensation, the existence of these non-condensable gases can make system condensing pressure raise, very large obstruction is caused to heat transfer process, apparatus of the present invention can be before the evaporation, solution gas in seawater is removed, improves the heat-transfer effect of vaporizer, reduce energy consumption;
4, the present invention utilizes interchanger by the waste heat recovery of condensation fresh water out in vaporizer and strong brine in order to pre-hot sea water, without the need to carrying out extra heat input to system, significantly reduces energy consumption;
5, the present invention sets up strong brine circulation tube, is circulated by part strong brine, effectively can maintain the stable of system, also reclaim waste heat efficiently simultaneously, reduced energy consumption.
6, the energy consumption of the inventive method can be reduced to traditional function of mechanical steam recompression method for desalting seawater 25% and following, greatly reduce sea water desaltination cost, simultaneously the present invention to equipment and site requirements lower, simple to operate, large-scale application and universal can be realized.
Accompanying drawing explanation
Below in conjunction with accompanying drawing and specific embodiment, the present invention will be further described in detail:
Fig. 1 is the floor map according to the integrated sea water desalinating plant of efficient MVR of the present invention;
Fig. 2 is the structural representation according to the integrated sea water desalinating plant of efficient MVR of the present invention;
Wherein: A, mainframe; B, pre-processing module; C, heating and waste heat recovery module; D, evaporation module; E, function of mechanical steam recompression module; F, housing; 1, chemicals dosing plant; 2,8, one-way control valve; 3, from backwash filter; 4, three-way pilot valve; 5, condensation fresh water heat exchanger; 6, strong brine interchanger; 7, vacuum degassing tower; 9, vaporizer; 10, scum dredger; 11, Mechanical Vapor Compression; 12, fresh water tank; 13, condensation fresh water production water pipe; 14, strong brine vent pipe; 15, strong brine circulation tube; 16, seawater pipeline; 17, recovery tube.
Embodiment
See Fig. 1, efficient mechanical vapor recompression sea water desalinating plant comprises mainframe A, 5 modules and connects the connecting tube of each module and provide extra large hydrodynamic pump.5 modules is respectively pre-processing module B; Heating and waste heat recovery module C; Evaporation module D; Function of mechanical steam recompression module E and housing F.Each module is produced and assembling according to same specification, realizes the versatility that product multi-series is arranged.In 5 modules except evaporation module D, equal piecemeal is arranged in mainframe A, and to make, structure is the compactest to be as the criterion in the concrete arrangement of these modules.Evaporation module D is located at outside mainframe A, facilitates the clean and maintenance of vaporizer.Mainframe A is rectangular parallelepiped, adopts framework design, specifically comprises inner frame, dismountable panel be arranged on inner frame, panel built-in heat insulation material layer, peripheral hardware sprayed coating.Panel offers ventilation hole.
Pre-processing module B comprise be communicated with seawater feed-pipe from backwash filter 3, one-way control valve 2 on the pipeline add the chemicals dosing plant 1 of medicament needed for pre-treatment in seawater feed-pipe, being arranged between chemicals dosing plant 1 and seawater feed-pipe, and the three-way pilot valve 4 seawater after filtering being divided into two tunnels.In addition pre-processing module B also comprises flow detection device, water temperature test set and Turbidity measurement equipment; all test sets are all connected with PLC control cabinet F and controlled; when turbidity exceedes system thresholds; this equipment can be closed down automatically; to protect other module to be polluted, now need to change the filter assemblies from backwash filter 3.
Heating and waste heat recovery module C comprise with the water side of three-way pilot valve 4 respectively by the condensation fresh water heat exchanger 5 of pipeline communication and strong brine interchanger 6, vacuum degassing tower 7, and fresh water tank 12, be provided with temperature testing equipment in the outlet of condensation fresh water heat exchanger 5 and strong brine interchanger 6, be connected with PLC control cabinet and controlled at condensation fresh water heat exchanger 5 and strong brine interchanger 6.Vacuum degassing tower 7 is arranged on the downstream of interchanger, for being removed by the room temperature incondensable gas in the seawater after preheating, thus improves the heat-transfer effect of vaporizer, reduces energy consumption.Take vacuum outgas mode, equipment is simple, and does not use any medicine in process.
Evaporation module D comprises vaporizer 9, scum dredger 10, one-way control valve 8, and wherein vaporizer 9 is the combined evaporative condenser that energy consumption is little.In vaporizer 9, be negative pressure for working pressure, seawater seethes with excitement and forms steam in vaporizer, and remaining seawater forms bittern.Pressure checking device, water temperature test set and brine concentration test set are installed in vaporizer 9.Steam sucks compressor by mechanical commprssor 11 after being processed by scum dredger 10 and compresses.The steam improving temperature and pressure reenters vaporizer 9 again and reuses as heating medium.The water produced after foam removal comes back in vaporizer 9 through recovery tube 17.Function of mechanical steam recompression module comprises Mechanical Vapor Compression 11, and it is variable frequency control compressor, and is equipped with temperature and pressure test set.
In this example, connecting tube mainly comprises the seawater pipeline 16 that two ends are communicated with vaporizer 9 with vacuum degassing tower 7 respectively, the condensation fresh water production water pipe 13 that two ends are communicated with condensation fresh water heat exchanger 5 with vaporizer 9 respectively, the strong brine vent pipe 14 that two ends are communicated with strong brine interchanger 6 with vaporizer 9 respectively, the strong brine circulation tube 15 that two ends are communicated with strong brine vent pipe 14 with seawater pipeline 16 respectively, the recovery tube 17 that two ends are communicated with the sea water conveying pipelines after scum dredger 10 and preheating respectively, one-way control valve 8 is arranged on strong brine circulation tube 15.
In this example, all movement parts in device and measuring instrument are all carry out Automated condtrol by PLC control cabinet, and each module and control valve group are all connected with PLC housing and controlled, achieve unattended operation and the continuous prodution of complete assembly.
The treatment agent of the impurity such as when the present invention carries out brine disposal, the seawater the first step processes by chemicals dosing plant 1 with from backwash filter 3 in pre-processing module B, removing silt and interpolation necessity.In heating and waste heat recovery module C, seawater reclaims the waste heat of strong brine and condensation fresh water through strong brine interchanger 6, water of condensation interchanger 5, after temperature is improved, enter vacuum degassing tower 7 and remove incondensable gas, enter after then mixing with circulation strong brine in vaporizer 9 and evaporate.In vaporizer 9, the seawater of spray to absorb heat outward boiling at prolong, and boiling seawater forms steam, and not boiling seawater forms strong brine.Steam compresses rear raising temperature and pressure and reenters vaporizer by entering Mechanical Vapor Compression 11 after scum dredger 10 foam removal again and reuse as heating medium.The water that foam removal produces is got back to vaporizer 9 from recovery tube 17.A part for the strong brine that evaporation produces is circulated back in vaporizer 9, and another part enters in strong brine interchanger 6 and discharges after heat exchange.
application example
Adopt apparatus of the present invention to carry out sea water desaltination, the water outlet ratio of fresh water is 50%, comprises the following step carried out continuously:
(1), sea water preprocessing: add flocculation agent, Scale inhibitors etc. by chemicals dosing plant in charging seawater, and the seawater after agent-feeding treatment is passed into filter from backwash filter, the impurity such as removing silt;
(2), seawater preheating: the seawater of filtered about 20 DEG C is divided into two tunnels, enter strong brine interchanger 6 and condensation fresh water heat exchanger 5(flow rate ratio is 1:1), strong brine interchanger 6 and condensation fresh water heat exchanger 5 pass into the strong brine of temperature about 75 DEG C and the condensation fresh water of temperature about 80 DEG C respectively, pass through heat exchange, the temperature of seawater is increased to about 70 DEG C, whole condensation fresh water that evaporation produces all are sent into condensation fresh water heat exchanger 5 and are carried out heat exchange, 90% of the strong brine that evaporation produces is sent into strong brine interchanger 6 and is carried out heat exchange, the strong brine discharge after heat exchange.Condensation freshwater product after heat exchange is disposed to fresh water tank 12;
(3), degassed: the seawater after preheating enters vacuum degassing tower 7, removes solution gas wherein, and these solution gass are the incoagulable gas of room temperature, comprise oxygen, nitrogen, carbonic acid gas etc.;
(4), evaporate, recompress: the seawater after degassed enters vaporizer 9 after mixing with the strong brine accounting for strong brine total amount 10%, evaporation is carried out under temperature 70 C and pressure 45KPa, improving temperature to 85 DEG C after the steam formed is compressed by Mechanical Vapor Compression 11 after scum dredger 10 foam removal is that the condensation in-tube condensation reentering vaporizer 9 after 57.8KPa again produces condensation fresh water with pressure, and the seawater simultaneously outside heating tube forms steam.
Take this apparatus and method, produce 100m
3desalination water, required energy consumption is about 2000kW.h.
comparative example
A kind of method for desalting seawater, the water outlet ratio of fresh water is 50%, and the method comprises the following step carried out continuously:
(1), seawater preheating: the seawater of about 20 DEG C carries out being preheated to 70 DEG C through the conventional seawater preheating device of Electric heating of taking;
(2), evaporate, recompress: seawater enters falling-film evaporator, in falling-film evaporator, evaporation is carried out under temperature 70 C and pressure 45KPa, seawater completes spray after distribution apparatus, the seawater of spray to absorb heat outward boiling at prolong, part forms steam, part forms strong brine, strong brine tank delivered to by strong brine, the steam formed is that the condensation in-tube condensation reentering vaporizer after 57.8KPa again produces condensation fresh water by improving temperature to 85 DEG C and pressure after compressor compresses, condensation fresh water delivers to fresh water tank, and the seawater simultaneously outside heating tube forms steam.Due to the existence of non-condensable gas, steam can discharge non-condensable gas gradually when condensation, can change the condensing pressure of steam after non-condensable gas adds up, and causes the fluctuation of system temperature.
Produce 100m
3desalination water, required energy consumption is about 8000kW.h.
Above to invention has been detailed description; its object is to allow the personage being familiar with this art can understand content of the present invention and be implemented; can not limit the scope of the invention with this; the equivalence change that all spirit according to the present invention are done or modification, all should be encompassed in protection scope of the present invention.