Background technique
Solar energy is meant the radiation energy of sunlight.The nuclear reaction by " hydrogen " fusion one-tenth " helium " in that solar interior carries out ceaselessly discharge huge energy, and constantly to the cosmic space radiation energy, this energy is exactly a solar energy.Solar energy is a kind of green, cleaning, the inexhaustible energy.Human just have three kinds substantially to the solar energy utilization: solar energy optical-thermal, photoelectricity and photochemical transformation of energy, and the conversion regime that is used to produce electric power has only the transformation of solar energy optical-thermal and photoelectricity.The form of photoelectric conversion is more single, and the main form of utilizing is a solar cell.The conversion regime that solar energy is thermoelectric and its apparatus are just many.A principle the most common of the thermoelectric conversion of solar energy is exactly to manage to obtain water vapor through the collection of solar energy, through the steam turbine acting, drives generator and produces electric power.
What routine solar light-heat power-generation system used all is the high temperature solar resource.The reason of the main use high temperature heat source of high temperature solar power generation system is that its turbine power generation unit is a conventional Rankine circulation power system, in order to guarantee its heat-economy, just must improve the initial temperature and the pressure of thermodynamic cycle.Solar energy resources is the lower resource of energy density, and this must assemble the energy of low energy densities through special device with regard to causing conventional solar light-heat power-generation, thereby can provide enough heats to add hot water, obtains the water vapor of HTHP.Such as the solar energy tower type generating, slot type generating etc. all need drop into huge fund and build solar aggregation apparatus.Below just introduce several frequently seen solar light-heat power-generation system.
One, tower type solar power generation system
This system sets up tall and big tower on spacious level land; Cat head installs and fixes a receiver and is equivalent to boiler; The heliostat that the disposed about of tower is a large amount of is assembled sunlight and reflex on the receiver of cat head producing high temperature, and the high-temperature steam pushing turbine that generates in the receiver generates electricity.
Tower type solar energy thermal power generation can be divided into two kinds again by the difference of heating working medium, and a kind of is the heating pure water, another kind of for adding hot brine solution.
In salt tower type solar heat utilization power station, thousands of day mirror with solar light focusing to the heat absorber of high building top, heat changes the saline solution in the heat absorber over to; Its temperature is elevated to 565 ℃ from 265 ℃; Pyrosol is delivered in the hot salt storage then, produces steam through steam generator, after the steam turbine acting; Get back to again in the cold salt storage after the condensation heat release cooling, squeeze in the heat absorber once more after boosting through the salt solution pump.
Although the starting of tower type thermal generation system early; People also hope through heliostat as much as possible solar energy to be gathered the level of tens megawatts always; But the cost of tower system is high always, and industrialization is difficult, and its basic reason is the design of heliostat system.The reflective surface that it is heliostat that the heliostat of at present typical tower type thermal generation system all has two characteristics one nearly all adopts common sphere or plane, and the 2nd, the traditional elevation angle, azimythal angle formula is all used in the tracking of heliostat.These two design features cause tower type solar optically focused receiver to exist the following problem that is difficult to overcome:
The first, the sun presented variation significantly at the hot spot that focuses on the tower within one day, caused the optically focused light intensity to fluctuate widely, and common sphere or planar mirror can't overcome the aberration that produces owing to solar motion.Because the card effect of the sun; The spot size that each reflector forms on central tower is along with the distance of it and central tower increases and linear growth; On the tower the last solar focusing hot spot that forms within one day can with the size of heliostat field from several meters change to tens meters big, so fluctuating widely appears in tower type solar energy thermal power generation station light light intensity.Add the different cosine effects of each heliostat, the photo-thermal conversion efficiency of tower system is merely about 60%.Although at present in the design of some tower systems of relatively being particular about; The sphere that different heliostats is begun to adopt different curvature radius to be reducing the size of sun focal beam spot on tower, but the optical design complexity increases greatly and causes manufacture cost also and then to increase substantially.
The second, numerous heliostats is set up around central tower, and the foundation of the central tower that floor space is huge must guarantee can not stop light mutually between each heliostat.Distance between each heliostat increases substantially along with the increase of they and central tower distance, thereby the floor space of tower type thermal generation system is index and increases sharply along with the increase of power level.
Because above-mentioned these problems although the tower type thermal generation system can realize 1000 ℃ focusing high temperature, are faced with the excessive problem of unit installed capacity investment always.The initial cost cost of tower system is 3.4 ten thousand~4.8 ten thousand yuan at present, and the cost reduction is very difficult, does not promote so tower system rests on demonstration phase over more than 50 year all the time and comes.
Two, groove type solar power generation system
This system a kind ofly reflexes to solar light focusing on the heat build-up pipe by the flute profile parabolic mirror, water is heated into the clean energy resource utilized device of steam pushing turbine generating through heat carrying agent in managing.The power in flute profile parabolic solar power station is 10~1000MW.Trough type solar power generation is prominent in present all solar energy thermal-power-generating stations.The heat transfer that system's heat collector collects is to the interior heat carrying agent that flows of pipe; Heat carrying agent can be water vapour, deep fat or salt solution etc.; Used reflector is processed by poor iron glass, and enough accuracy of manufacturing must be arranged for it so that sunlight reflection effectively under any circumstance.
The reflector that the flute profile parabolic solar collector is adopted is parabolic post.Sunlight reflected focuses on point-blank; The vacuum tube glass heat collector that is placed on the focal line absorbs the solar radiation that is focused; Temperature can reach 400 ℃, and high temperature heat-carrying matter heats the water generates water vapor in Intermediate Heat Exchanger, and self temperature descends; Flow back to the solar thermal collector heat absorption through heat-carrying matter recycle pump, constitute thermal source one loop.The water vapor that produces is the turbine acting in steam turbine, drives generator for electricity generation, and exhaust is condensed into water in condenser, after condensate pump and feed water pump boost, returns Intermediate Heat Exchanger again, continues to circulate, and this constitutes second loop.
The slot type system has replaced the pipeline of point focusing and focusing along with the cylinder parabolic mirror is followed the tracks of solar motion together with linear focusing; With regard to having solved the not high problem of photo-thermal conversion efficiency that tower system causes owing to focal beam spot is inhomogeneous, photo-thermal conversion efficiency is brought up to about 70% like this.It is the tracking that can't realize under the fixed target that but the slot type system also brings a new problem, causes system mechanics heavy.Because the focusing pipeline in the middle of the solar receiver is fixed on the slot type reflector; Along with each slot type reflector of reflection all is a big whole minute surface of length and width; Windage is very big; The supporting structure that must change or add intensive reflector must cause initial cost cost and hot cost of electricity-generating to increase to increase the wind resistance of slot type system like this.
The receiver of slot type system is long, and heat diffusion area is big, and the solar receiver of slot type system is the very long heat absorption tube of root, although developed many new extinction technology.But its heat radiation comprises that the heat diffusion area that is caused by thermal radiation is bigger than its effective light-receiving area, therefore compares with tower with a type focusing system such as dish formula, and the heat loss of slot type system is bigger.
Three, disc type solar energy power generation system
The parabolic mirror that the disc type solar energy power generation system is made up of mirror more than 2000 is formed.Receiver is guided to 600~2000 ℃ the thermal source of collecting in the Stirling engine on paraboloidal focus, and heat-transfer working medium is heated to about 750 ℃, drives generator at last and generates electricity.The dish reflector is followed the tracks of sun's motion and is moved, and has overcome the loss problem of the big cosine effect of tower system, and photo-thermal conversion efficiency improves greatly, generally up to about 85%.
Dish formula receiver with solar focusing on the focus of the paraboloid of revolution; Again because solar concentrator and Stirling engine can extraordinary combination produce electric energy; It is that the net efficiency of electric energy can reach 29.4% with solar energy converting, is most effective in all solar electrical energy generations so Stirling circulates in the identical temperature range of operation.The disc type solar energy power generation system is used flexibly, both can make distributed system and supply power separately, also can generate electricity by way of merging two or more grid systems.
Disc type solar energy power generation system and groove type solar power generation system and tower type solar power generation system more as shown in the table:
|
Tower |
Slot type |
The dish formula |
Operating temperature (℃) |
500-1000 |
260-400 |
500-1500 |
Sun light concentrating times |
600-1000 |
8-80 |
200-3000 |
Photo-thermal conversion efficiency (%) |
60 |
70 |
85 |
Cost of investment (solar energy generates electricity with the hybrid system that other dyestuffs are formed) (ten thousand yuan/KW) |
3,4 |
2,2 |
4,7 |
Cost of investment (using solar electrical energy generation separately) (ten thousand yuan/KW) |
4,8 |
4,4 |
6,4 |
Can know that through this table disc type solar energy generating operating temperature and optically focused are than being maximum, its photo-thermal conversion efficiency ranks first at the similar system meta up to about 85%.The shortcoming of dish formula system is to involve great expense, and also is to occupy the first place in this system.The initial cost cost of dish formula heat generating system is up to 4.7 ten thousand~6.4 ten thousand yuan at present.The optically focused of pipe-dish type system is higher than very to the greatest extent, can reach 2000 ℃ high temperature, but high temperature like this does not need or even has destructive for present hot generation technology.So; The receiver of dish formula system generally is not placed on the focus; But require suitably to be placed in the lower humidity province according to performance index, in fact the advantage of high like this optically focused degree can not be fully played and the thermmal storage difficulty, and hot melt salt heat-storage technology is greatly dangerous and cost is high.
In sum; Existing three kinds of solar light-heat power-generation technology all belong to the high temperature solar generation technology; This has just increased the solar thermal collector performance demands greatly, also just certainly will increase the fund input at the solar energy heating apparatus, has increased initial investment.
Summary of the invention
The purpose of this invention is to provide a kind of cheap and solar ammonia water thermoelectric conversion system that cycle efficiency is high.
In order to achieve the above object; Technological scheme of the present invention has provided a kind of solar ammonia water thermoelectric conversion system, it is characterized in that, comprises at least one vacuum tube ammoniacal liquor heat collector; The water outlet of vacuum tube ammoniacal liquor heat collector connects the water intake of ammoniacal liquor gas-liquid two-phase separator; The gaseous state outlet of ammoniacal liquor gas-liquid two-phase separator connects the inlet of turbine engine, and turbine engine is through gearbox and generator electric knot, and the liquid low concentration ammonia water out of ammoniacal liquor gas-liquid two-phase separator is with the common hot side-entrance that connects heat exchanger of weary gas outlet of turbine engine; This side outlet of heat exchanger gets into storage ammonia jar, and the cold side of heat exchanger connects with condensation unit.
Ammonia water mixture from storage ammonia jar gets into vacuum tube collector; After being heated to form the ammoniacal liquor two-phase mixture, separate through the separator gas-liquid two-phase, the ammonia steam of gas phase directly promotes turbine engine; Turbine engine is through gearbox and generator electric knot and then generation electric energy; The liquid phase low density ammoniacal liquor mixture that separated device is separated is through weary depressed close of nozzle with turbine engine, and ammonia water mixture just comes back to original concentration like this, through getting back to storage ammonia jar after the condensing plant cooling once more; Go round and begin again, realize continuous running based on the solar ammonia water thermoelectric conversion system of vacuum pipe solar ammoniacal liquor heat collector.
Solar ammonia water thermoelectric conversion system provided by the invention belongs to the low-temperature solar energy photothermal power generation; With respect to the high temperature solar generation technology; It adopts low-temperature heat source in the utilization of kalina circulating technology; Its cycle efficiency exceeds 20~50% in the conventional Rankine circulation of middle low temperature range internal ratio, and this is very considerable in the energy utilization.Adopt vacuum tube collector to collect solar energy heating ammoniacal liquor, its technology maturation, economically feasible, and its photo-thermal conversion efficiency is up to more than 95%, and this is that other solar thermal collectors institutes are unsurpassable.
Advantage of the present invention is: equipment is simple, arranges compactness, but complete production, cost is lower, and every kilowatt of initial cost is about 1.6 ten thousand yuan; The vacuum tube solar heating element thermal efficiency is high, η>=95%, and technology maturation, cost is lower; Kalina circulates in low temperature (≤150 ℃) section, and cycle efficiency is high, and it is high by 20~50% to circulate than conventional Rankine; Solar ammonia water thermoelectric conversion system is stable, and is safe and reliable, can realize unattendedly, and maintenance period is long, and maintenance cost is low, and cost of electricity-generating is low; Applied widely, particularly solar energy resources and geothermal resources all abundant area will be more practical.
Embodiment
Specify the present invention below in conjunction with embodiment.
Embodiment
As shown in Figure 1; Schematic representation for a kind of solar ammonia water thermoelectric conversion system provided by the invention; Comprise the one group of vacuum tube ammoniacal liquor collector system that matches with the generator set electromotive power output; Vacuum tube ammoniacal liquor collector system is made up of the vacuum tube ammoniacal liquor heat collector 1 of a plurality of series connection/parallel connection, and the outlet of vacuum tube ammoniacal liquor heat collector 1 connects two of ammoniacal liquor gas-liquid two-phase separator 20 and enters the mouth mutually, and the ammonia outlet of ammoniacal liquor gas-liquid two-phase separator 20 connects turbine engine 5; Turbine engine 5 connects with generator 7 through gearbox 6 mutually; The outlet of weary gas and the low concentration ammonia water out of ammoniacal liquor gas-liquid two-phase separator 20 of turbine engine 5 is connected the hot side-entrance of condenser 22 respectively, this side outlet of condenser 22 connect storage ammonia jar 2 import, the cold side connection condensation unit 3 of condenser 22; The outlet of storage ammonia jar 2 links to each other with water pump 23, and water pump 23 will store up the ammoniacal liquor of the fixed concentration in the ammonia jar 2 and squeeze into vacuum tube ammoniacal liquor collector system once more.
The Kalina cycle fluid adopts ammonia-water mixed working fluid, and the ammoniacal liquor mixed working fluid has following physicochemical characteristic:
(1) unfixed boiling point and condensation point temperature;
(2) thermophysical property can change with the change of ammonia concentration;
(3) under the constant situation of thermal capacity, the temperature of mixture can change;
(4) low-down freezing point temperature;
(5) alkalescent.
Ammoniacal liquor thermal parameter under different pressure, temperature and the concentration situation: the equation of state of the ammonia water mixture that the calculating of enthalpy, specific volume and entropy can be formulated based on NIST (American National technical standard research institute).Utilization NIST8.0 computer program calculates.
Utilization of the present invention be exactly the characteristics that ammonia water mixture has unsettled boiling temperature, can dwindle heat transfer temperature difference with thermal source.On thermal curve as shown in Figure 4, the heat absorption evaporator section, ammonia water mixture does not have the level pressure endothermic process, it can than the pure water of routine Duo the suction a part of heat.At condensating section, in like manner ammoniacal liquor does not have fixing condensation point, and at the heat release condensating section, it just can put a part of heat less.Many heat absorptions, few heat release, efficiency of thermal cycle can obtain raising.
Shown in Fig. 2 A to Fig. 2 C, be the structural representation of vacuum pipe solar ammoniacal liquor heat collector, vacuum tube collector 1 comprises a plurality of vacuum tubes 8; Supporting structure 11 through the outside is fixing, scribbles coating for selective absorption on the tube wall in vacuum tube 8, its absorptivity α s >=95%; Its conversion efficiency ε >=90%; In vacuum tube 8, be provided with the multi-disc fin 9 of level/vertically place, do not have the U-shaped pipe 10 of middle heat transfer medium to pass fin 9 in the pipe and be located in the vacuum tube 8, the two ends of U-shaped pipe 10 are located at outside the vacuum tube 8; The end of two adjacent U-shaped pipes 10 interconnects, just like this shown in Fig. 2 A 12 vacuum tubes 8 be arranged in series.
Fig. 3 is the schematic representation of condensation unit; Comprise condenser 29; Top in condenser 29 is provided with spray equipment 25, and the condensation side outlet of condenser 29 connects cooling tower 26, and the outlet of cooling tower 26 is the 3rd circulating water pump 27 and the 28 back condensation side imports that connect condensers 22 of the 3rd throttle valve successively.