CN113375360A

CN113375360A - Multistage cascade type solution adjusting device and method

Info

Publication number: CN113375360A
Application number: CN202110492772.1A
Authority: CN
Inventors: 郑喜勋
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-05-06
Filing date: 2021-05-06
Publication date: 2021-09-10
Anticipated expiration: 2041-05-06
Also published as: CN113375360B

Abstract

The invention discloses a multistage cascade type solution regulating device, which comprises n condensing tanks and m evaporating tanks, wherein n and m are integers more than or equal to 1, any one of the tanks is provided with at least one solution pipeline which is communicated with other tanks, the communicated tank can be a condensing tank or an evaporating tank, any one of the evaporating tanks is communicated with one of the condensing tanks through a steam pipeline, solution is introduced into one of the condensing tanks and one of the evaporating tanks through pipelines, the concentration range of the solution comprises the full range from pure solute to pure solvent, namely 0-100%, and at least one solution source exists. The invention discloses a multistage cascade solution adjusting device which can continuously concentrate solution, improve the solubility of the solution and enable the concentration of the solution to meet the standards of the industries such as chemistry, food, environment, biological pharmacy and the like.

Description

Multistage cascade type solution adjusting device and method

Technical Field

The invention relates to the technical field of solution concentration and pressure regulation, in particular to a multistage cascade type solution regulating device and method.

Background

The concentration and dilution of the solution are widely applied to the industries of chemistry, food, environment, biological pharmacy and the like, and can also be used for acting devices, absorption refrigeration equipment, heat pump equipment and the like by utilizing osmotic pressure.

For example, the gas absorption refrigeration mainly includes an ammonia absorption refrigeration/heat pump, and the energy efficiency ratio of the absorption refrigeration is lower than that of the mechanical compression refrigeration because the absorption refrigeration/heat pump firstly cools and reduces the pressure of a dilute solution generated in a generator, then enters an absorber, absorbs refrigerant vapor generated by an evaporator to form a concentrated solution, then conveys the concentrated solution to the generator by a pump body, and the vapor generated in the generator is further rectified to separate ammonia gas, and then is condensed into liquid ammonia. So circulating, continuous steam power needs to be generated. The energy efficiency ratio of absorption refrigeration is lower than that of mechanical compression refrigeration, and the reason is that the concentration of a solution of a gas solute is lower when the solution is fed into a generator, most of the solution is a solvent, and a large amount of the solvent is evaporated while the solute is evaporated by heating, so that a large amount of heat energy needs to be input. Meanwhile, when the solute is dissolved in the solution, the solution heat is generated; when a solute is precipitated from a solution, it needs to absorb heat. The heat of solution is not utilized, so that double the energy is required and eventually exhausted to the environment, resulting in inefficiency. The invention aims to further concentrate the solution before the solution is sent into the generator, improve the concentration of the solution and play a role in reducing the heat energy input in the generator. Meanwhile, the solution heat is utilized to play a role in reducing energy payment for heating the solution. Solution concentration can also be used in many industries that rely on osmotic pressure to do work.

There is therefore a need for an apparatus and method to increase the concentration of a gaseous solute solution to meet the standards of the chemical, food, environmental, biopharmaceutical, etc. industries or to increase the thermal efficiency of absorption refrigeration/heat pumps.

The invention provides a multistage cascade solution adjusting device and method, which can be used for solving the problems.

Disclosure of Invention

The present invention is directed to a multi-stage cascade solution adjusting apparatus and method, so as to solve the problems of the background art.

In order to solve the technical problems, the invention provides the following technical scheme: a multi-stage cascade solution adjusting device comprises n condensing tanks and m evaporating tanks, wherein the n condensing tanks comprise first-stage condensing tanks, second-stage condensing tanks and n-stage condensing tanks, the m evaporating tanks comprise first-stage evaporating tanks, second-stage evaporating tanks and m-stage evaporating tanks, the n and m are integers which are more than or equal to 1, at least one solution pipeline is communicated between any one of the condensing tanks and one of the evaporating tanks or between the evaporating tanks, any one of the evaporating tanks and one of the condensing tanks are communicated through a steam pipeline, solutions are introduced into one of the condensing tanks and one of the evaporating tanks through pipelines, the concentration range of the solutions comprises the full range from pure solutes to pure solvents, namely, the range from 0% to 100%, and at least one solution source is provided. The invention utilizes the characteristic that the solubility of the solution of the gas solute is reduced along with the rise of the temperature and is increased along with the rise of the pressure, and the multi-stage overlapping can continuously concentrate the solution, improve the solubility of the solution, ensure that the concentration of the solution meets the standards of the industries of chemistry, food, environment, biological pharmacy and the like, or improve the thermal efficiency of the absorption refrigeration/heat pump.

Preferably, the evaporation tank is a device for generating steam, and the generation mode comprises various modes such as heating evaporation, flash evaporation and the like.

Preferably, a heat exchanger is arranged in any one of the condensing tanks or at an outlet of any one of the condensing tanks, the heat exchanger is selected to be arranged in the condensing tank or at the outlet of the condensing tank according to the effect to be achieved by the tank, or the heat exchanger is arranged in the condensing tank, or the heat exchange working medium is switched on or switched off according to the requirement although the heat exchanger is arranged in the condensing tank, so that the heat exchanger is started or stopped, the heat exchanger is arranged in any one of the evaporating tanks, and the condensing tank is connected with the evaporating tank through the heat exchanger or directly flows into the heat exchanger through solution to exchange heat with the solution in the tank; or the heat exchangers are connected through pipelines between the heat exchangers and the environment, and a heat exchange working medium flows between the heat exchangers and the pipelines and is used for transferring heat. When the solution heat is only needed to be utilized to obtain higher temperature, the heat exchanger in the condensing tank is stopped, and when the solution in the condensing tank reaches the required temperature, the solution flows out of the condensing tank and exchanges heat with the heat exchanger at the outlet of the condensing tank, so that heat is transferred out. When the solution concentration is increased and the heat generated by dissolving heat is utilized, the temperature of the solution in the condensing tank is controlled by the heat exchanger in the condensing tank. For example, the heat of the solution in the condensing tank is directly transferred to the solution in the evaporating tank or transferred to the solution by a heat exchange working medium. The solution in the evaporation tank is preheated, even directly heated to promote evaporation, so that the power of an external heat source for heating the solution in the evaporation tank is reduced. When the concentration of the solution is to be increased to the maximum, heat is transferred to low-temperature places such as the environment through a heat exchanger in the condensation tank.

Preferably, the n condensing tanks and the m evaporating tanks can be connected in parallel or in series, the solution in one of the n condensing tanks or one of the m evaporating tanks flows into the condensing tank and the evaporating tank of the next stage through pipelines, the pipelines in parallel connection can be combined together, and the solution flowing out of one of the n condensing tanks can enter the evaporating tank of the next stage or the evaporating tank of the next stage; the solution flowing out of the next-stage evaporation tank can enter a condensation tank or enter the next-stage evaporation tank.

Preferably, a vapor compression device is arranged in the middle of a vapor pipeline of the evaporation tank to the condensation tank.

Preferably, the steam outlet of one of the m evaporation tanks or the outlet of one of the n condensation tanks is connected with an application device, and the application device is any one of a work doing device, a membrane filtering device, a heat exchanger, a rectifying device and a steam compressing device.

Preferably, the heat exchangers are connected by a heat exchange working medium system, and working medium flowing out of one heat exchanger enters the other heat exchanger to mutually transfer heat.

Preferably, a certain level of evaporating pot also has the evaporating pot of pipeline UNICOM next level, and the steam of this evaporating pot not only can let in the condensing pot of the same grade like this, also can let in the evaporating pot of next level. When the aim is to increase the concentration of the solution, the heat of the solution in the condensation tank is transferred to the environment or other low-temperature areas. When the temperature of the environment or the low temperature is too low, the temperature of the solution in the condensation tank is too low, and the liquidity of the solution is affected. In order to reduce the number of pumps, the solution in the system does not flow, and only the steam flows. For example, during operation, steam in the primary evaporation tank flows into the primary condensation tank, the heat exchanger in the primary condensation tank cools the solution, the heat exchanger in the secondary evaporation tank heats the solution, and the steam flows into the secondary condensation tank. When the evaporation and the condensation reach a certain degree, the valves of the heat exchange working medium pipeline and the steam pipeline are switched, so that the heat exchanger in the original primary condensation tank starts to heat the solution; the heat exchanger in the original secondary evaporation tank begins to cool the solution; meanwhile, steam in the primary evaporating pot begins to enter the original secondary evaporating pot, and the original primary condensing pot and the original secondary evaporating pot are exchanged.

Preferably, an auxiliary solution is introduced to meet the requirements of solution temperature regulation and concentration regulation.

Preferably, a compressor is arranged in the middle of the steam pipeline, the compressor is used for conveying steam in the evaporation tank into the condensation tank, and the steam pressure in the evaporation tank and the steam pressure in the condensation tank are adjusted through the compressor, so that the steam pressure in the condensation tank is increased, and the dissolution is promoted; the vapor pressure in the evaporation tank is reduced, the evaporation of the solution is promoted, and the solution with lower concentration is obtained.

Preferably, the compressor is a vapor jet pump. The steam in the evaporating pot is injected by using the steam generated by heating a solution with a certain concentration or an auxiliary solution as working steam, and then the mixed steam enters the condensing pot together. As the mature prior art, the ejector pump can eject steam in the evaporating pot with the pressure lower than that of the working steam, so that the evaporation of the solution is promoted, the concentration efficiency is improved, and the equipment investment is reduced.

Preferably, a solution having a concentration is prepared according to the purpose of preparing the solution and then flows to the subsequent step. The solution outlet of the n-grade condensation tank is communicated with a work doing device, the work doing device does work by means of osmotic pressure, the work doing device belongs to the prior art, and details are not described herein, if the requirement on the purity of solute is not high, the solute can be directly cooled and condensed by a heat exchanger at the outlet of an evaporation tank; or filtering with membrane and condensing; or after being compressed by a vapor compression device, the liquid solute is condensed. The n-stage condensing tank can be followed by a generator and a rectification device. The solution outlet of the n-grade condensation tank can also be connected with the subsequent process of solution concentration.

Preferably, the first heat exchanger and the second heat exchanger are communicated through a compressor system, and the compressor system is a single compressor system or a two-stage compression system with a low-pressure compressor and a high-pressure compressor matched with each other.

Preferably, the compressor system is a vapor compression system, the vapor compression system is used in parallel with the above single-stage compressor system or a two-stage compression system in which a low-pressure compressor and a high-pressure compressor are combined, or is used in parallel with an absorption refrigeration/heat pump system, and the single-stage compressor, or a suction end of the low-pressure compressor, or an absorber of the absorption refrigeration/heat pump system becomes a low-pressure component of the vapor compression system. The vapor compression system comprises a compression assembly, a work applying assembly and a low-pressure assembly, wherein the heat exchanger is respectively communicated with the compression assembly and the work applying assembly through a vapor pipeline, the compression assembly is communicated with the heat exchanger II through a vapor pipeline, the work applying assembly is communicated with the low-pressure assembly through a pipeline, the low-pressure assembly is a suction end of a compressor of the single-stage compressor or the low-pressure compressor or an absorber of an independent absorption refrigeration system and is connected with the suction end of the compressor or the absorber of the independent absorption refrigeration system, and the independent absorption refrigeration system plays a role in enhancing and cooling the solution of the condensing tank. The heat of liquid in the condensation jar is absorbed to the steam in the heat exchanger, carry respectively through the pipeline and get into compression subassembly and acting subassembly after steam pressure increases, let in the steam pressure in the compression subassembly put, with the low pressure subassembly between have a pressure difference, this pressure difference produces the drive power that makes steam flow direction low pressure subassembly, this drive power drive acting subassembly does work, with the vapor compression in the compression subassembly, the steam of compression in the compression subassembly after that, get into the condensation in No. two heat exchangers, the solution in the heating evaporation jar during the condensation, then the liquid after the condensation, get back to the heat exchanger once more and circulate once more. The steam compression system can be matched with the single-stage compressor system and the two-stage compressor system matched with the low-pressure stage and the high-pressure stage, only part of steam is compressed, more high-pressure steam can be obtained, and particularly, the steam compression system is matched with an absorption type refrigeration system, so that the efficiency can be improved. The first heat exchanger is used for the compression assembly and the work application assembly at the same time, two heat exchangers are not needed, and equipment investment can be saved.

Preferably, the compressor system is a vapor compression system, the vapor compression system comprises a compression assembly, a work applying assembly and a low-pressure assembly, the heat exchanger is respectively communicated with the compression assembly and the work applying assembly through vapor pipelines, the compression assembly is communicated with the heat exchanger through the vapor pipelines, and the work applying assembly is communicated with the low-pressure assembly through a pipeline.

Preferably, the vapor outlet of the evaporating pot is respectively communicated with the compression assembly and the work applying assembly through vapor pipelines, the compression assembly comprises the vapor outlet of the evaporating pot, a heat exchanger, a liquid outlet and a compressed vapor outlet, the liquid outlet is connected with the evaporating pot, the work applying assembly comprises a low-pressure assembly, and the low-pressure assembly is one of the n condensing pots.

Preferably, the vapor compression device at the outlet of the evaporator is also similarly configured. The difference lies in that a heat exchanger and a liquid outlet are arranged between a compression component of a vapor compression device at the outlet of the evaporation tank and the outlet of the evaporation tank according to the vapor pressure and the temperature of the evaporation tank. The heat exchanger is used for condensing the solvent working medium in the steam and discharging the solvent working medium through a liquid outlet. The liquid discharged from the liquid outlet is high-concentration solution, so that the high-concentration solution is discharged back to the evaporation tank, or the solution discharged from the liquid outlet is heated, so that part of steam and steam subjected to heat exchange by the heat exchanger enter the compression assembly together, and the compressed steam is condensed. If the temperature of the solution in the evaporation tank is lower, the solution can be directly compressed and condensed without passing through a heat exchanger. And the rest steam flowing out of the evaporating pot is used as the working steam and enters the working assembly to work so as to drive the compression assembly. The low-pressure component is a certain condensing tank with lower pressure in the system.

Preferably, the method for the multi-stage cascade solution adjusting device comprises the following steps:

s1, introducing a solution with the concentration needing to be changed into a condensing tank and an evaporating tank;

s2, heating the solution in the evaporation tank to promote evaporation, introducing steam into a condensation tank to dissolve the steam into the solution in the condensation tank, and adjusting the solution into a solution with a required concentration;

s3, introducing an auxiliary solution, and improving the concentration and the temperature of the solution by using the auxiliary solution;

s4, increasing the concentration of the solution in the condensing tank, and obtaining the required temperature by using the solution heat;

s5, according to the purpose of the condensation tank, processing the temperature of the solution in the condensation tank, and when the temperature of the solution reaches the required temperature, enabling the solution to flow out of the condensation tank and exchange heat with a heat exchanger at an outlet of the condensation tank to send heat to an application device in order to obtain a high-temperature solution; in order to obtain a solution with a certain concentration and simultaneously utilize the solution heat, a heat exchanger in a condensing tank is utilized to control the temperature in the condensing tank to keep the required temperature, and the heat is brought to an application device or a certain evaporating tank in a system through a heat exchange working medium to preheat or evaporate the solution by using the solution heat; in order to obtain a solution with a certain concentration, the temperature of the solution is reduced or heat is discharged to the environment through a heat exchanger in a condensation tank;

s6, obtaining a required dilute solution or concentrated solution for use through the transfer of steam;

s7, if the solute needs to be purified, after the concentration of the solution is increased to the required concentration, the temperature of the solution is reduced to the normal temperature, the solution is introduced into an evaporation tank, the pressure of the evaporation tank is reduced until the solute is precipitated from the solution, meanwhile, the temperature of the solution is reduced, the high-concentration solution is evaporated at a low temperature, and the purity of the obtained solute steam is improved due to the low temperature of the solution, the low evaporation temperature and the low partial pressure of the solvent.

Sometimes not only a solution of a certain concentration is required, but also a liquid solute of a certain purity, such as an absorption refrigeration/heat pump device. If the required purity is not very high, a heat exchanger can be arranged at the outlet of the evaporation tank of a certain stage. And after the steam pressure in the evaporating pot meets the requirement, the steam flows out of the evaporating pot and is condensed in the heat exchanger. In order to further improve the purity, a membrane filtering device can be added, and a small amount of solvent working medium in the steam is filtered and condensed. The conventional cooling method can also be adopted to reduce the solvent steam in the steam. At the moment, the steam to enter the compression assembly needs to be cooled, the solvent working medium in the steam is condensed after heat exchange, and the steam pressure of the solute working medium is lower than the steam pressure corresponding to the heat exchanger. Therefore, the ratio of solute in the steam passing through the heat exchanger is improved, and the purity is improved. After passing through the heat exchanger, a small amount of liquid appears along with the condensation of the solvent working medium, and the liquid is a high-concentration solution. Discharging the solution and directly returning the solution to the evaporation tank, or heating the solution to separate out partial solute vapor and then returning the solute vapor to the evaporation tank; and part of the steam flowing out of the evaporating pot enters the acting component to drive the compression component, and the steam flowing out of the acting component enters one of the condensing pots.

Or evaporating the solution at low temperature after increasing the concentration of the solution, thus reducing the partial pressure of the solvent vapor in the vapor, and condensing the solute into liquid meeting the purity requirement after the component ratio of the solute in the vapor meets the requirement.

Compared with the prior art, the invention has the following beneficial effects: the invention discloses a multi-stage cascade solution adjusting device and a method, which divide a solution to be treated into two parts by utilizing the characteristics that the solubility of a solution of a gas solute is reduced along with the rise of temperature and is increased along with the rise of pressure, one part is heated, and the steam of the heated solution is introduced into the rest part of the solution to improve the concentration of the solution. And taking the solution with the improved concentration as a solution to be treated of a second stage, heating one part of the solution, and continuously receiving steam generated by the heating part to improve the concentration of the solution. The multi-stage overlapping can continuously concentrate the solution, improve the solubility of the solution, lead the concentration of the solution to meet the standards of the industries such as chemistry, food, environment, biological pharmacy and the like, or improve the thermal efficiency of the absorption refrigeration/heat pump. In the process of increasing the concentration, the generated solution heat is directly exchanged by the heat exchanger or the heat exchange working medium is transferred by the heat exchanger and the pipeline according to the process requirements or the requirements of other parts, so that the effect of utilizing the solution heat is achieved. While introducing an auxiliary solution, simplifying the process, or for obtaining higher temperatures.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic structural diagram of a first embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a fourth embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a fifth embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a sixth embodiment of the present invention;

in the figure: a condensing tank-1; a steam line-2; an evaporator-3; heat exchanger-4; a compression assembly-5; a work-doing component-6; low-voltage component-6-1; a second heat exchanger-7; low-voltage component-8; a first-stage evaporation tank-9; a secondary condensing tank-10; a first-stage condensation tank-11; a secondary evaporator-12; a primary first-stage condensing tank-13; a main first-stage evaporation tank-14; a subsystem first-level evaporation tank-15; a subsystem first-stage condensing tank-16; subsystem two-stage evaporator-17; subsystem secondary condensing tank-18; a secondary evaporator-19; a solution-20 to be treated from an ammonia absorption refrigeration system absorber; a primary evaporator tank-21 of the absorption refrigeration system; solution after primary heating-22; a secondary condensing tank-23 of the absorption refrigeration system; a secondary evaporator tank-24 of the absorption refrigeration system; a heat exchanger-25 outside the condensing tank; ammonia vapor-26 for increasing the concentration; a heating and heat supply ammonia generator-27; heating and heat supply condensing tank-28; a first-stage condensing tank-29 of the absorption refrigeration system; the absorption refrigeration system has treated solution-30.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1: as shown in fig. 1, a solution having a constant concentration is obtained, and ammonia is used as an example, but the solution may be not limited to ammonia or a gas such as carbon dioxide. Ammonia water with certain concentration respectively enters the evaporating pot 3 and the condensing pot 1, the evaporating pot 3 is communicated with the condensing pot 1 through the steam pipeline 2, and solution is heated in the evaporating pot 3 to generate steam with higher pressure. Under the action of the pressure difference with the steam in the condensing tank 1, the steam in the evaporating tank 3 enters the condensing tank 1. The dissolution of the solute into the solution is promoted due to the increase of the pressure of the condensation tank 1, and the temperature of the solution is increased due to the heat of dissolution. The heat exchanger in the condensation tank 1 transfers the generated heat to a low temperature place such as the environment and other places where heat is needed. In this case heat can be transferred to the inlet of the evaporation tank 3, preheating the solution that is about to enter the evaporation tank 3, and then the remaining heat is transferred to the environment. Thus, the heating quantity in the evaporating pot 3 can be reduced, and the effect of saving energy is achieved.

Further, in order to utilize the solution heat more, a first heat exchanger 4 and a second heat exchanger 7 are respectively arranged in the condensation tank 1 and the evaporation tank 3, and the two heat exchangers are connected through a vapor compression device. And a condensing tank is added at the same time, as shown in the following figure. Since the evaporation tank 3 heats the solution and delivers the vapor to the condensation tank 1, the pressures of both the condensation tank 1 and the evaporation tank 3 are relatively high. Therefore, a condensing tank is added as a low-pressure component 8 to absorb steam from the acting component 6, the low-pressure component 6-1 is communicated with the acting component 6 and increases the pressure to act on the compression component 5, and then the compressed.

After the concentration of the solution is adjusted, the solution in the evaporating tank 3 and the condensing tank 1 flows to a required place after being cooled.

Example 2: for ammonia absorption refrigeration/heat pumps, assuming a 23% concentration of ammonia to be treated, 1 bar. It is necessary to reduce the ammonia water concentration to 18% while obtaining high-purity liquid ammonia. The invention firstly concentrates the solution, heats the solution after improving the concentration of the solution, and then condenses the generated steam into liquid ammonia. Since not all of the solution is fed to the generator for heating, less total heat is required than in the prior art. Meanwhile, the purpose of energy saving is achieved by utilizing the heat of solution and crystallization as much as possible.

23 percent, the temperature of 1bar of ammonia water is about 40 ℃, when the ammonia water with the concentration is heated to 80 ℃, the pressure is 2bar, the saturation concentration is 0.141 and 100 ℃, and the concentration is 0.057 when the pressure is 2bar, according to the situation on site, when steam resources exist, 100 ℃ is selected, and when hot water resources exist, 80 ℃ is selected. Thus, the solution after the first-stage evaporation tank and the heating treatment has the concentration lower than the required concentration. Can be mixed with the solution to be treated to prepare 18 percent solution, and can also be used for enhancing the absorption capacity of ammonia water by using low-concentration solution.

The temperature of the first-stage condensing tank is 20 degrees in winter, and 40 degrees in summer. Thus, it can be known from the table that the concentration of the first-stage condensation tank can reach more than 40% in winter and 30% in summer. The heat exchanger transfers the heat of the first-stage condensation tank to the environment or other places. The solution in the first-stage condensation tank is moved to a second-stage evaporation tank, and when the solution is heated to 70 ℃, 40 percent of the solution can be heated to 7bar in winter; the 30% solution in summer can be heated to 4.3 bar. In winter, the pressure can be directly condensed into liquid ammonia, and in summer, the secondary evaporation tank needs to be heated to a higher temperature, about 80 ℃ or 100 ℃.

In this case, if appropriate, the water vapor is separated by a separation membrane and condensed directly in a heat exchanger.

The solution temperature of the secondary evaporation tank is set to about 45 ℃, so that the partial pressure of the water vapor in the steam is reduced as much as possible. Meanwhile, the rest steam is compressed by using the steam compression device and the steam of the secondary evaporation tank. The steam entering the compression assembly is cooled by the heat exchanger, and the content of the steam is reduced again. And (3) discharging a small part of solution from the liquid outlet, and directly sending the solution back to the secondary evaporation tank, or slightly heating the solution to release high-pressure ammonia gas in the solution and then returning the solution back to the secondary evaporation tank. The working steam enters the second-stage condensing tank after passing through the working assembly, the solution concentration in the second-stage condensing tank is further improved, the solution concentration is gradually increased from 40% of the first-stage condensing tank initially, the solution concentration in the second-stage evaporating tank is also increased, and the pressure of the last second-stage condensing tank can be directly condensed. The partial pressure of the water vapor at 20 ℃ is very low, so that the purity requirement of the liquid ammonia can be met.

In summer, the temperature of the secondary evaporating pot is still 80 degrees or 100 degrees because the ambient temperature is higher than that in winter, and the temperature of the secondary condensing pot is kept at 40 degrees, so that the concentration of the secondary condensing pot can be respectively increased to more than 50 percent and more than 60 percent. At the moment, the liquid ammonia with higher purity can be obtained according to the method adopted in winter.

Further, in winter, due to low environmental temperature, the solution temperature is low after heat exchange with the environment, and the fluidity is poor. Thus, the purpose of the first condensation tank and the second evaporation tank can be determined by whether the solution in the tanks is heated or cooled. The first-stage evaporating pot is provided with a steam pipeline which is respectively connected with the first-stage condensing pot and the second-stage evaporating pot. The first-stage condensing tank and the second-stage evaporator are connected with the second-stage evaporating tank through pipelines. The purpose exchange is completed through the switching of the valve.

In this embodiment, the solution may also be directly fed to the rectification apparatus after flowing out of the first-stage condensation tank.

Example 3: although the embodiment 2 is energy-saving compared with the prior method, the equipment investment is more, the process is somewhat complex, especially in summer, the auxiliary solution is introduced, and the auxiliary solution is pure liquid ammonia or liquid ammonia with high purity and is applied to the same process.

The solution of 23 percent and 1bar respectively enters a first-stage condensing tank and a first-stage evaporating tank, and is heated to 80-100 ℃ in the first-stage evaporating tank. The steam that liquid ammonia was heated the production is as working steam, draws the steam in the injection one-level evaporating pot, and the steam after the mixture gets into the one-level condensate tank, dissolves in the one-level condensate tank. The ammonia water with the concentration is heated to 80-100 ℃, and the steam pressure is 2-3 bar. Because of being injected by ammonia gas, the vapor pressure of the ammonia water in the evaporation tank is reduced, 1bar is kept, the ammonia water is evaporated under the pressure of 1bar, the concentration of the ammonia water at 80 ℃ is 0.062, namely 6.2%, and the concentration is lower at 100 ℃. The low-concentration ammonia water flows out of the primary evaporating pot and is mixed with the solution to be treated to prepare 18 percent. The heat exchanger in the primary condensing tank will increase in temperature as the concentration increases, subject to the heat of solution. The heat exchanger in the condensing tank transfers heat to the primary evaporating tank and preheats the solution entering the evaporating tank; the ammonia gas is transferred to the liquid ammonia to be continuously evaporated and maintain constant pressure.

And the solution is moved from the first-stage condensing tank to the second-stage condensing tank, and ammonia steam is continuously sent into the second-stage condensing tank to improve the concentration of ammonia water in the tank. The temperature in the secondary condensing tank keeps constant, and the heat exchanger continuously transfers heat to the liquid ammonia, so that the liquid ammonia generates enough pressure and enough amount of steam for improving the concentration and subsequent requirements of the solution. For example, the solution is maintained at 60 degrees, and the heat exchange working medium continuously transfers heat of 60 degrees to the liquid ammonia, so that the liquid ammonia continuously generates 22bar of pressure for increasing the concentration of the liquid ammonia in the secondary condensation tank until the vapor pressure in the secondary condensation tank reaches the pressure, and the concentration of the solution is about 90 percent.

And (3) conveying the concentrated 90% solution to a secondary evaporation tank from a secondary condensation tank, and reducing the temperature of the solution to normal temperature through a heat exchanger at an outlet of the condensation tank in the process. The solution entering the secondary evaporation tank is evaporated to generate steam due to low vapor pressure in the secondary evaporation tank, and the temperature of the solution is continuously reduced. At a steam outlet of the secondary evaporation tank, injecting ammonia water steam in the secondary evaporation tank by the ammonia steam of about 22bar, and condensing the mixed steam into liquid ammonia in a condenser; or compressed by a vapor compression device and then condensed. The vapor compression device comprises a compression assembly, a work doing assembly and a low-pressure assembly. The driving steam is the superheated steam of 22bar, enters the acting assembly to act, and enters the low-pressure assembly after driving the compression assembly, wherein the low-pressure assembly is a condenser connected with the environment and can also be working steam for injecting steam in the primary evaporation tank. And the steam in the secondary evaporation tank enters a compression assembly, and is compressed and then enters a condenser connected with the environment for condensation.

The temperature of the solution in the secondary evaporation tank is kept at 5-10 ℃, and the purity of the liquid ammonia is high due to low temperature and high concentration of the solution, low partial pressure of water vapor in steam and high proportion of ammonia gas in the steam.

The secondary evaporator tank is evaporated at low temperature and becomes a refrigeration evaporator. The ammonia gas steam can be condensed at the place, then the liquid ammonia exchanges heat with the cooling water of the power plant, and the steam in the first-stage evaporation tank is injected by being heated to evaporation.

And when the concentration in the second-stage evaporation tank is reduced to a certain degree, returning the solution to the second-stage condensation tank, and recycling after the concentration is increased again.

The above process parameters are only for illustrating the application method, and do not represent the best solution, and the best solution should be selected according to the technical conditions. The temperature requirement which cannot be met by the solution heat needs to be provided by an external heat source.

Further, in order to reduce the number of tanks, a two-tank or three-tank system may be used according to the refrigeration requirement.

The two-tank type has only one evaporating tank and one condensing tank. Firstly, in an evaporation tank, the solution is heated and evaporated into dilute solution with extremely low concentration, after a certain amount of dilute solution is stored according to the refrigerating capacity, the evaporation tank stops preparing the dilute solution, and the evaporation tank is emptied. At the same time, the condensing tank is constantly increasing the solution concentration. And after the solution in the condensing tank meets the requirement, the solution flows out of the condensing tank. And after heat exchange and temperature reduction through the outlet heat exchanger, the solution enters the evaporation tank and is evaporated in the evaporation tank, and meanwhile, the temperature of the solution is reduced. Then the steam is injected by an ejector at the outlet of the evaporation tank, the working steam is high-purity high-pressure ammonia gas, and the high-purity high-pressure ammonia gas is condensed into liquid ammonia after being mixed. The concentration in the evaporation tank is reduced to a certain degree, the evaporation is stopped and the remaining solution is sent back to the condensation tank.

The solution of 23% and 1bar to be treated enters the evaporating pot again, becomes dilute solution after being heated and evaporated, and returns to the refrigerating system. For a system with larger refrigeration load, a mode of one evaporating tank and two condensing tanks is adopted. The first-stage condensing tank receives the steam injected by the solution to be treated, and the second-stage condensing tank is specially used for increasing the concentration and providing heat to evaporate the liquid ammonia.

Example 4: and (3) refrigerating by using concentrated ammonia water instead of liquid ammonia, as shown in figure 2.

The concentrated ammonia solution enters a refrigeration evaporator, namely a primary evaporation tank after throttling, and the ammonia water is evaporated because the steam pressure in the evaporator is lower than the saturated pressure. The dilute solution enters the absorber of the refrigeration system, the absorber becomes a first-stage condensation tank 11, and the steam flows into the first-stage condensation tank from the first-stage evaporation tank because the steam pressure of the first-stage condensation tank is lower than that of the first-stage evaporation tank. The solution in the first-stage condensation tank flows into the second-stage evaporation tank 12, is heated and evaporated in the evaporation tank 12, and the vapor flows into the second-stage condensation tank 10, so that the concentration of the solution flowing from the first-stage evaporation tank 9 is increased.

Preferably, the solution flowing out of the first-stage condensation tank firstly enters a heat exchanger in the second-stage condensation tank, absorbs the heat of the solution in the second-stage condensation tank, and enters the second-stage evaporation tank after being preheated; or the heat exchanger in the secondary condensing tank transfers part of the heat to the inlet of the secondary evaporating tank to preheat the solution entering the secondary evaporating tank 12, so that the heating energy consumption is reduced, and the rest heat is transferred to the environment or is output as a heat source.

Example 5: as shown in fig. 3, the energy-saving ammonia concentrated solution absorption refrigeration/heat pump system. The absorber of the refrigeration system constitutes the main first-stage condensation tank 13, and the evaporator of the refrigeration system constitutes the first-stage evaporation tank. The solution flowing out of the main first-stage evaporation tank 14 is divided into two paths, one path enters the first-stage evaporation tank 15 of the subsystem, and the rest enters the first-stage condensing tank 16 of the subsystem, and the heat exchanger in the first-stage evaporation tank 15 of the subsystem is connected with the heat exchanger in the main first-stage condensing tank 13, so that the solution in the first-stage evaporation tank of the subsystem is heated and evaporated by transferring the solution heat in the first-stage condensing tank to the solution in the first-stage evaporation tank of the subsystem. The steam in the first-stage evaporation tank 15 of the subsystem enters the first-stage condensation tank 16 of the subsystem and is dissolved in the solution in the first-stage condensation tank 16. The solution in the first-stage condensation tank 16 of the subsystem can completely enter the second-stage condensation tank 18 of the subsystem, or part of the solution meeting the concentration requirement returns to the main first-stage evaporation tank 14 (the evaporator of the refrigeration system), and the rest part enters the second-stage condensation tank 18 of the subsystem.

The solution flowing out of the subsystem primary evaporation tank 15 enters the subsystem secondary evaporation tank 17 and is heated and evaporated. The steam in the secondary evaporation tank of the subsystem enters a secondary condensation tank 18 of the subsystem and is dissolved in the solution. In the secondary condensation tank 18 of the subsystem, the solution meeting the concentration requirement transfers heat to other solutions, an output heat source or environment, returns to the primary evaporation tank, namely the evaporator of the refrigeration system, and is evaporated again after the temperature is reduced.

The solution flowing out of the main first-stage condensation tank 13 enters the second-stage evaporation tank 19 and is heated and evaporated. Preferably, the solution is first preheated by the solution in the secondary condensation tank of the sub-system (by directly entering the heat exchanger in the secondary condensation tank of the sub-system or conducting heat through a heat exchange working medium), and then heated to the required temperature.

The steam generated in the secondary evaporation tank 19 enters the primary condensation tank of the subsystem with lower steam pressure and is dissolved in the solution in the primary condensation tank. Furthermore, the steam is injected by a steam injection pump and is evaporated under low pressure, so that the concentration of the solution is further reduced. The injection steam can come from the secondary evaporation tank 19 or the subsystem secondary evaporation tank 17.

The dilute solution meeting the concentration requirement returns to the main first-stage condensation tank 13, namely the absorber of the refrigeration system, and absorbs the steam from the main first-stage evaporation tank 14, namely the evaporator of the refrigeration system.

Further, the subsystem first-stage evaporation tank 15 can be reduced, and the solution entering the subsystem second-stage evaporation tank 17 is preheated by the main first-stage condensation tank 13 (the solution in the main first-stage evaporation tank 14 passes through a heat exchanger in the first-stage condensation tank, exchanges heat with the solution in the main first-stage condensation tank 13, enters a heat exchanger in the subsystem second-stage condensation tank 18, is preheated, and then enters the subsystem second-stage evaporation tank 17) and the subsystem second-stage condensation tank 18, then enters the subsystem second-stage evaporation tank 17, and is finally heated by an external heat source.

The steam in the second-stage evaporation tank 19 enters the first-stage condensation tank of the subsystem and is dissolved in the solution.

Further, the secondary evaporation tank 19 can be reduced, further reducing the equipment investment. The solution flowing out of the main first-stage condensing tank 13 passes through a heat exchanger in a second-stage condensing tank 18 of the subsystem, is preheated and then heated by an external heat source, steam enters a first-stage condensing tank 16 of the subsystem, and the solution returns to the main first-stage condensing tank 13 to be circulated again.

Example 6: as shown in fig. 4, the cooling water of the power plant in winter is centrally heated: the temperature in winter is considered according to 15 ℃, and the corresponding vapor pressure is 7 bar; the temperature of the cooling water of the power plant is 32 ℃, and corresponds to the vapor pressure of 12 bar. The vapor pressure of the final ammonia water is shown, and the ammonia water can be condensed when reaching 8bar after being lifted, and the maximum vapor pressure for lifting the solution concentration is 12 bar. The primary network target for heating (without considering other external heat sources) is 120/20 degrees, the feed water reaches 120 degrees, the backwater is 20 degrees or even lower, but the backwater temperature of some old facilities is 50 degrees.

An ammonia absorption refrigeration/heat pump utilizes power plant cooling water to heat heating water.

As can be seen from the total vapor pressure of ammonia, heating the heating water to 120 deg.C requires a low ammonia concentration as the initial solution. From example 3 we can make a 6% dilute solution. In addition, the pressure of ammonia gas for raising the concentration must reach more than 20bar, and the cooling water of a power plant cannot reach the pressure, so that heat is required to be obtained from the solution heat.

The whole body is divided into two parts, wherein one part is an ammonia absorption type refrigerating system, the other part is a heating water heating system, and the two parts are combined together as shown in the figure. On the basis of the four-tank mode in the example 3, a heating heat supply condensing tank and a heat exchanger at the outlet of the museum are additionally arranged between a first-stage condensing tank and a second-stage condensing tank. In a heating heat supply condensation tank, the solution is heated to the highest temperature, and then flows out to exchange heat with a heat exchanger at an outlet, so that heat is transferred to primary network backwater of heating.

The two systems are combined for use in winter, and 2, 4, 5 and 10 tanks are used in non-heating seasons. The solution in the first-stage condensation tank 29 of the absorption refrigeration system directly flows into the second-stage condensation tank 23 of the absorption refrigeration system.

The solution to be treated enters the primary evaporation tank 21 of the absorption refrigeration system, is heated to 80-100 ℃, and is heated by the condensate water of the power plant to generate the primary condensation tank 29 of the absorption refrigeration system. The dilute solution is treated in a primary evaporation tank to obtain about 6 percent dilute solution, the dilute solution is divided into two paths after flowing out, one path of the dilute solution goes to an absorption refrigeration system, the other path of the dilute solution enters a primary condensation tank 29 of the absorption refrigeration system and then is mixed with injected steam (a dotted line part), and the steam is dissolved into the solution under the action of pressure and generates solution heat to improve the temperature of the solution. After the concentration and temperature reach a certain degree, the solution enters the heating and condensing tank 28. Liquid ammonia is heated and evaporated by cooling water of a power plant and solution heat generated by increasing the concentration of the solution in the heating and heat supply ammonia generator 27, and then enters the heating and heat supply condensing tank 28 to improve the concentration and the temperature of the solution. After reaching a certain degree, the water flows out of the heating and heat supply condensing tank 28, and exchanges heat with the return water of the heating primary network in the heat exchanger at the outlet to reduce the temperature. The solution concentration is expected to be around 30% at this time, a temperature slightly higher than that of the solution of the absorption refrigeration system. In order to save equipment cost, the two solutions are jointly processed, the solution flowing out of the heat exchanger enters a first-stage evaporation tank of the absorption refrigeration system, and the rest solution enters a second-stage condensation tank of the absorption refrigeration system. The solution entering the first-stage evaporation tank is recycled after most of solute is separated out to become dilute solution; the separated ammonia enters a first-stage condensing tank for recycling.

The solution entering the secondary condenser of the absorption refrigeration system was processed in the same manner as in example 3.

Example 7: on the basis of example 4, the heat exchanger is connected to a power plant. During non-heating seasons, hot water can be continuously produced. The hot water is connected with the low-boiling-point power generation device to provide power for the low-boiling-point work doing device.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-stage cascade solution adjusting device is characterized in that: including n condensing tanks and m evaporating pots, n the condensing tank includes one-level condensing tank, second grade condensing tank, the evaporation pot includes one-level evaporating pot, second grade evaporating pot, n level condensing tank, m the evaporation pot includes one-level evaporating pot, second grade evaporating pot, the evaporation pot of the other grade of the evaporation pot of the grade, n and m are all integers more than or equal to 1, arbitrary one of the pots, no matter condensing tank or evaporating pot, at least one of the pot and at least one of the evaporation pot, at least one of the evaporation pot and one of the evaporation pot pass through the pipeline and let in solution, the solution concentration range includes from pure solute to the full range of pure solvent, namely between 0% -100%, and has at least one solution source.

2. The multi-stage cascade solution conditioner according to claim 1, wherein: the evaporation tank is a place where the solution is evaporated and generates steam, and the evaporation mode in the evaporation tank comprises various evaporation methods such as heating evaporation and flash evaporation.

3. The multi-stage cascade solution conditioner according to claim 1, wherein: the condensation tank or the condensation tank is provided with a heat exchanger at the outlet, the evaporation tank is internally provided with a heat exchanger, the condensation tank is connected with the evaporation tank through the heat exchanger, or the heat exchanger is connected with the environment through a pipeline, and solution or heat exchange working medium flows between the heat exchanger and the pipeline for transferring heat.

4. The multi-stage cascade solution conditioner according to claim 1, wherein: the n condensing tanks and the m evaporating tanks are connected in parallel or in series, the solution in one of the n condensing tanks or one of the m evaporating tanks flows into the condensing tank and the evaporating tank of the next stage through pipelines respectively, the parallel pipelines can be combined together, the solution flowing out of one of the n condensing tanks enters the evaporating tank of the next stage, and the solution flowing out of the evaporating tank of the next stage enters the condensing tank.

5. The multi-stage cascade solution conditioner according to claim 1, wherein: and a steam compression device is arranged in the middle of a steam pipeline of the evaporation tank to the condensing tank.

6. The multi-stage cascade solution conditioner according to claim 1, wherein: and a steam outlet of one of the m evaporation tanks or an outlet of one of the n condensation tanks is connected with an application device, and the application device is any one of a work doing device, a membrane filtering device, a heat exchanger, a rectifying device and a steam compression device.

7. The multi-stage cascade solution conditioner according to claim 3, wherein: and the heat exchanger in the condensing tank is communicated with the heat exchanger in the evaporating tank through a compressor system.

8. The multi-stage cascade solution conditioner of claim 7, wherein: the compressor system is a vapor compression system, the vapor compression system comprises a compression assembly, a work applying assembly and a low-pressure assembly, the heat exchanger is respectively communicated with the compression assembly and the work applying assembly through vapor pipelines, the compression assembly is communicated with the heat exchanger through the vapor pipelines, and the work applying assembly is communicated with the low-pressure assembly through a pipeline.

9. The vapor compression device as recited in claim 8, wherein a vapor outlet of the evaporator tank is respectively communicated with the compression assembly and the work applying assembly through a vapor pipeline, the compression assembly comprises a vapor outlet of the evaporator tank, a heat exchanger, a liquid outlet and a compressed vapor outlet, the liquid outlet is connected with the evaporator tank, the work applying assembly comprises a low pressure assembly, and the low pressure assembly is one of the n condensing tanks.

10. The method for the multi-stage cascade solution conditioner according to any one of claims 1 to 9, comprising the steps of: