The multilevel vacuum distilling sea water desalinating plant
(1) technical field
The utility model relates to a kind of multilevel vacuum distilling sea water desalinating plant, is mainly used in seawater (or brackish water) desalination.Belong to field of sea water desalting technology.
(2) background technology
The method that seawater or brackish water are desalinated is a lot, and conventional method has distillation method, ion exchange method, dialysis, reverse osmosis membrane and cold method etc.The method that the most extensively is studied in distillation method and uses mainly is multistage flash evaporation (MSF) sea water desalinating plant and multi-effect distilling (MED) sea water desalinating plant.
Multistage flash evaporation (MSF) sea water desalinating plant is to utilize the waste heat in power plant, chemical plant continuously to extract the very little high-quality fresh water of total solids material content from seawater, as the process water and the large-scale municipal water use of production process.Accompanying drawing 1 is a kind of schematic diagram of multistage flash evaporation.
Flash principle is salt solution to be heated to introduce after the certain temperature in the container (being called flashing chamber) that pressure is lower than the corresponding saturation pressure of its temperature institute, owing to salt solution is in superheat state suddenly, promptly dodges anxious distillation (abbreviation flash distillation) wink.The steam that produces removes in the devaporation behind the drop by scum dredger, enters distiller and condenses into product fresh water, and the circulating brine that flows through the distiller tube bank simultaneously also is heated.Flashing chamber, scum dredger, distiller, fresh-water tank etc. constitute flash evaporator.Multistage flash evaporation is exactly to carry out said process in the container of a plurality of such ordered arrangement.
The feature of multi-effect distilling (MED) desalination technology is that horizontal pipe falling film evaporation device (or vertical tube falling-film evaporator) is together in series, and with a certain amount of steam input, by repeatedly evaporation and condensation, obtains being multiple times than the distilled water of heating steam amount.Accompanying drawing 2 is schematic diagrams of a kind of multi-effect distilling (MED) sea water desalinating plant.
Among Fig. 2, the charging seawater is preheated in the heat extraction condenser and outgases, and is divided into two bursts of logistics afterwards.One logistics flows back to the sea as cooling fluid after finishing cooling effect, one logistics becomes the feeding liquid of still-process in addition.
Feed liquid is introduced in heat-recovery section and respectively imitates in minimum one group of temperature after adding dirt dispersion agent.Sprinkling system is distributed to feed liquid spray on the overhead coil in each vaporizer, along overhead coil downwards with form of film in the free-pouring process, a part of seawater is vaporized owing to having absorbed in vaporizer the latent heat of condensed steam.By slight spissated residue feed liquid with pump be driven into vaporizer next the group in, the service temperature of this group than last one group higher, in new group, repeated evaporation and spray process again.Remaining feed liquid is then beaten forward, to the last leaves this effect group with the form of concentrated solution in the highest effect group of temperature.
First phlegma of imitating is collected, and the part of this distilled water turns back to vapour generator again, and the part that surpasses the living quantity of steam of input flow in the first container of a series of special containers, and each container all is connected to the condensation side that next low temperature is imitated.Make a part of distilled water produce flash distillation like this and remaining product water cooling is got off, heat is passed in the main body that recovery of heat imitates gone simultaneously.As distilled water, concentrated seawater is from a series of strong brine flash tank of the first stepped inflow of effect, and flash cooling is to reclaim its heat.After overcooling, strong brine is squeezed into the sea through the strong brine pump.
In above-mentioned dual mode sea water desalinating plant, the vapor temperature that the multistage flash evaporation sea water desalinating plant need be imported is higher, and temperature is low excessively to cause progression to reduce, and efficient reduces.Because 1 ton of fresh water of the every desalination of multistage flash evaporation sea water desalinating plant needs 8 tons of seawater circulations through this device, therefore must need powerful water circulating pump, its maximum shortcoming is exactly the energy consumption height.Effect distillation seawater desalinating device of multi then needs complicated seawater spraying system, sprinkling system is the key part of effect distillation seawater desalinating device of multi, spray flux evenly makes tube surface well wetting in the spray zone in vaporizer, non-uniform spraying will cause the local dried wall of heat-transfer surface, easily fouling, cause condenser early failure and heat-transfer effect to worsen, spray performance quality is directly connected to the safe operation of effect distillation seawater desalinating device of multi.Seawater is to flow to the first step from last step in effect distillation seawater desalinating device of multi, and the temperature that concentrated seawater is discharged is very high, must carry out waste heat recovery, therefore, and the manufacturing complexity of this method, manufacturing cost height.
(3) summary of the invention
In order to overcome the shortcoming of above-mentioned two kinds of sea water desalinating plants, the utility model provides a kind of does not have spray equipment, the multilevel vacuum distilling sea water desalinating plant of fresh water waste heat recovery is arranged, and its temperature of discharging concentrated seawater is low, concentration can be regulated; And the fresh water waste heat recovery has improved the moisturizing temperature of first evaporator, has eliminated surfusion.Thereby have low cost of manufacture, a advantage that thermo-efficiency is high.
The utility model is achieved in that
The multi-stage vacuum sea water desalinating plant is by some groups of placed in-line vacuum distilling apparatuses, water cooler, well heater, and the fresh water heat recovery heat exchanger is formed, every group of vacuum distilling apparatus is made up of vaporizer, condenser, fresh-water tank, the condenser of previous stage is immersed in the seawater of back one-level vaporizer, and the previous stage vaporizer links to each other with the vaporizer of next stage through flow control valve; The steam that the last step vaporizer produces enters the last step condenser that places in the water cooler; Normal temperature seawater at first enters water cooler, enters the fresh water afterheat heat exchanger then, enters in the first step vacuum-evaporator by flow control valve at last; Fresh water in the fresh-water tanks at different levels at first passes through the fresh water afterheat heat exchanger, is then taken away; And concentrated seawater is taken away, is discharged in the last step vaporizer.
(4) description of drawings
Fig. 1 is the schematic diagram of a kind of multistage flash evaporation (MSF) sea water desalinating plant.
Fig. 2 is the schematic diagram of a kind of multi-effect distilling (MED) sea water desalinating plant.
Fig. 3 is a synoptic diagram of the present utility model.
Among Fig. 3: the 1st, well heater, the 2nd, first evaporator, the 3rd, first step fresh water jar, the 4th, first step condenser, the 5th, second stage vaporizer, the 6th, second stage fresh water jar, the 7th, second stage condenser, the 8th, third evaporator, the 9th, the last step vaporizer, the 10th, last step fresh water jar, the 11st, the last step condenser, the 12nd, the water cooler of last step condenser, the 13rd, be the flow control valve of first evaporator moisturizing, the 14th, first evaporator is to the flow control valve of second stage vaporizer moisturizing, the 15th, first step fresh water jar take out the fresh-water flow variable valve, the 16th, second stage vaporizer is to the flow control valve of third evaporator moisturizing, the 17th, second stage fresh water jar take out the fresh-water flow variable valve, the 18th, the flow control valve of the discharge concentrated seawater of last step vaporizer, the 19th, last step fresh water jar take out the fresh-water flow variable valve, the 20th, the fresh water afterheat heat exchanger.
(5) embodiment
Fig. 3 is an embodiment of the present utility model.
At first, first evaporator (2) is seethed with excitement by well heater (1) heating, after the steam that produces enters first step condenser (4) by pipeline, being condensed into distilled water after the cooled with seawater in the second stage vaporizer (5) enters first step fresh-water tank (3), the Absorption by Sea Water latent heat of condensation in the second stage vaporizer (5) is until boiling simultaneously, the steam that produces flows into second stage condenser (7), condensed after the cooled with seawater in the third stage vacuum-evaporator (8), water of condensation flows in the second stage fresh-water tank (6).Third stage vacuum-evaporator is heated boiling.By that analogy, the subsequent stages vacuum distilling apparatus is successively by the previous stage ebuillition of heated.The steam that last step vaporizer (9) boiling produces enters the condenser (11) of last step, and condenses after the cooled with seawater in the device that is cooled (12), and agglomerative distilled water enters last step fresh-water tank (10).
First step fresh-water tank (3), second stage fresh-water tank (6), the fresh water in last step fresh-water tank (19) and other fresh-water tanks at different levels pass through flow control valve (15,17 and 19 etc.) respectively and enter seawater in fresh water afterheat heat exchanger (20) heating heat exchanger.And normal temperature seawater at first enters water cooler (12), with the heat of condensation that absorption last step vacuum distillation plant condenser (11) produces, and the fresh water afterheat heat exchanger (20) of flowing through again, the fresh water that is produced by vacuum distilling heats, thereby has realized fresh water waste heat recovery process.
Seawater process by fresh water afterheat heat exchanger (20) heating enters first step vacuum-evaporator (2) for the flow control valve (13) of first evaporator moisturizing, and the seawater in the first evaporator is by for the flow control valve (14) of second stage vaporizer moisturizing be second stage vaporizer (5) moisturizing, and the interior seawater of second stage vaporizer (5) pass through for the flow control valve (16) of third evaporator moisturizing be third evaporator (8) moisturizing; And the like, the vaporizer of previous stage is back one-level vaporizer moisturizing by flow control valve respectively.Because the pressure in the previous stage vaporizer is higher than the pressure of back one-level, so the moisturizing process only needs suitably to regulate flow control valve and can finish automatically.In the moisturizing process, because the boiling temperature of previous stage vaporizer is higher than back one-level vaporizer, therefore after the seawater of previous stage vaporizer enters the next stage vaporizer, at first some seawater generation flash distillation, then with this grade vaporizer in together explosive evaporatoin of seawater, the steam of generation enters condensation in the condenser of this grade.
Whole water replanishing device relies on flow control valve that the seawater liquid level in the vaporizers at different levels is remained on the appropriate location.The steam that vaporizers at different levels produce is at first removed sea water drops by the scum dredger of this grade, then enters condenser.
18 is flow control valves that concentrated seawater is discharged among Fig. 3, by this flow control valve concentrated seawater is extracted out.Control concentrated seawater delivery flow variable valve (18) can be controlled the flow of taking concentrated seawater away, thereby controls the concentration of seawater in this grade vaporizer; The flow of taking concentrated seawater away is big more, and the concentration of concentrated seawater is low more, and the concentration of the more little concentrated seawater of flow is high more.Suitably dominant discharge variable valve (18) can be controlled at the concentration interval that helps improving vaporization efficiency and fresh water quality most with the concentration of discharging concentrated seawater.
In the such scheme, the thermal source of well heater (1) can be the waste heat of chemical plant or power plant, also can be the hot water that solar energy system produces, also directly electricity consumption under special circumstances, coal or Sweet natural gas heating.