CN113772801B

CN113772801B - Carbonic acid solution adding system

Info

Publication number: CN113772801B
Application number: CN202111137285.XA
Authority: CN
Inventors: 林峡
Original assignee: Harvey Shanghai Environmental Technology Co ltd
Current assignee: Harvey Shanghai Environmental Technology Co ltd
Priority date: 2021-09-27
Filing date: 2021-09-27
Publication date: 2024-02-20
Anticipated expiration: 2041-09-27
Also published as: CN113772801A

Abstract

The invention discloses a carbonic acid solution adding system. It includes a mixer and a diffuser; the device also comprises a carbon dioxide gas pipeline and a reaction water pipeline; a water pump is arranged on the reaction water pipeline; the outlet of the water pump is connected with the inlet of the mixer; the carbon dioxide gas pipeline is connected with the inlet of the mixer; an annular coil pipe or a liquid storage tank and a long-distance pipeline are arranged between the mixer and the diffuser; the diffuser is arranged in the water to be treated; the side wall of the diffuser is provided with a passage for releasing carbonic acid solution, and the passage for releasing carbonic acid solution is a small hole or a narrow gap or a combination of the small hole and the narrow gap; the channel for releasing carbonic acid solution can generate certain back pressure and enable supersaturated carbonic acid solution to be sprayed into water to be treated at certain outlet pressure, so that the pressure difference between the outlet pressure of the diffuser and the water to be treated is ensured to be more than 2 bar. The carbonic acid solution adding system can accurately adjust water quality, meanwhile, can greatly reduce the generation of bubbles, and greatly improve the utilization rate of carbon dioxide gas.

Description

Carbonic acid solution adding system

Technical Field

The invention belongs to the technical field of water treatment, and relates to a carbonic acid solution adding system for adjusting the pH value of water, remineralizing or lime softening and other applications.

Background

The pH value of the water body is too high and exceeds pH value of 8.0 or even 9, and the subsequent chemical treatment and product quality are seriously affected by the too high and unstable pH value of the water body. For example, the pH of the wastewater end effluent should be controlled to be 6-9; in the process of coagulation and disinfection of a tap water plant, excessive addition of chemical agents is caused due to excessively high and unstable pH, excessive chemical byproducts are generated, and the effluent can not reach the relevant national standard; in the textile printing and dyeing industry, the pH of printing and dyeing process water is unstable, the color fastness of a product is affected, and the defective rate and the fading of the product are caused; in natural water bodies such as rivers, lakes and the like, the pH value is too high and is changed in a waveform due to factors such as oxygen enrichment, algae burst and the like of the water bodies; in water bodies such as fish ponds, shrimp ponds, swimming pools and the like, the pH value is too high due to the addition of bactericides and disinfectants; the vegetable greenhouse and flower planting requires additional carbon dioxide gas to strengthen photosynthesis, and carbon dioxide content can be increased by using carbonated water for irrigation, so that the growth of crops is facilitated; .. water is not located, and is closely related to life and production of people, and the accurate control of the pH of water body is an important ring in the water treatment process flow.

The pH, also known as the hydrogen ion concentration index, the pH value, is a scale of the activity of hydrogen ions in a solution, i.e., a measure of the degree of acid and base in the solution in a general sense. Neutral aqueous solution ph=7 acidic aqueous solution, pH < 7, the greater the pH value, the more basic. The pH value is one of important physical and chemical parameters of water and sewage, and the pH value is one of important indexes of water treatment field control. Adjusting and controlling the pH may promote chemical reactions and create specific physicochemical changes.

In order to adjust the pH of water, an acidulant such as sulfuric acid or hydrochloric acid is mainly used to neutralize the pH of water; the acidulant belongs to strong acid, and the strong acid has various safety problems such as storage, transportation and corrosion, importantly, the pH value is hard to be accurately regulated by using the strong acid, and more importantly, the strong acid destroys alkaline substances in water in the acid-base neutralization reaction process, and the alkaline substances are indispensable in drinking water.

At present, many petrochemical plants around the country are provided with carbon dioxide purification equipment on a large scale under the guidance of relevant national policies, and produce food-grade carbon dioxide gas, so that the price of the carbon dioxide gas is greatly reduced, and the carbon dioxide gas is also convenient for users to purchase locally. Because the cost and the gas resource are easy to obtain, the operation cost of the carbonic acid adding system is almost equal to the use cost of reducing the chemical agent, and through case implementation, the user only needs to input initial equipment cost, so that the acid-base value of the water is economically feasible by utilizing carbonic acid for neutralization.

Since carbonic acid is a weak acid and has a buffer zone when reacting with an alkaline substance, the pH can be precisely controlled or adjusted to a set value required by a customer by utilizing the neutralization reaction of carbonic acid. In addition, most of carbon dioxide gas is derived from petrochemical waste gas, and pH of water neutralized by carbonic acid solution is the process of carbon dioxide consumption and complete reaction, and carbon dioxide is not released into the atmosphere again, so that greenhouse effect can be reduced, and carbon neutralization is realized.

In the water treatment production process flow of a tap water plant, coagulation and disinfection are essential important links, and how to adjust the pH of raw water, so that the use of chemical agents and byproducts are reduced, and the method has important significance.

In the seawater desalination process, the seawater is subjected to multistage filtration to obtain the permeable water which is acidic and corrosive due to the removal of minerals, lime is required to be added to remineralize the water, and then carbonic acid is required to react with calcium carbonate which is difficult to dissolve in the water to generate water-soluble calcium bicarbonate, so that the water with the minerals added can be drunk by people.

In sewage treatment, because the hardness of the wastewater is high, people need to add lime to carry out lime softening treatment on the hard water, and then add carbonic acid to combine with calcium ions in the wastewater to generate calcium bicarbonate, so that the hardness of the wastewater is reduced; lime softening treatment is to add slaked lime Ca (OH) 2 into water to react with alkaline components in the water to generate indissolvable CaCO3, wherein slaked lime is a strong alkali substance, the pH of the water after slaked lime is added can reach more than 10, high pH water needs acid neutralization, carbonic acid can be used for accurately regulating the pH to a value desired by a customer, meanwhile, carbonic acid reacts with indissolvable CaCO3 generated in the reaction process of slaked lime and water to generate water-soluble calcium bicarbonate, H2CO3+CaCO3-C=Ca (HCO 3) 2, and the problems of pipeline blockage and the like caused by sediment generation are avoided.

There are also known prior art techniques in which carbon dioxide gas is used to neutralize the ph of water. Carbon dioxide gas is dissolved in water to produce carbonic acid. Solubility, defined as the amount of a particular substance that can be dissolved in a particular solvent (yielding a saturated carbonic acid solution). The solubility (solubility) of carbon dioxide in water at normal temperature and pressure is limited. The carbon dioxide gas needs to react with water for a long time to produce carbonic acid, a process called recarbonation. Thus, the dissolution of carbon dioxide in water is a very slow chemical reaction process which reacts with water to form carbon dioxide (in the form of a water-soluble liquid), carbonic acid, bicarbonate ions and hydrogen ions as the carbon dioxide gas molecules enter the water, of the formula:

CO2+H2O->CO2+H2CO3+HCO3(-)+H(+)；

why this is a very slow chemical reaction process, which is slow because it has to break the double bond between oxygen and carbon (see formula below), which takes time.

One way to neutralize the pH of water using carbon dioxide gas is to directly add carbon dioxide gas to neutralize the pH of water, the adding system needs a large reaction tank with a stirrer, carbon dioxide gas generates small bubbles through a diffuser, and the CO2 small bubbles react with alkaline substances in water for a long time and distance to achieve the purpose of lowering the pH. However, small CO2 bubbles can escape from water in the whole reaction process, the effective utilization rate of carbon dioxide gas can only be between 30 and 60 percent, the low utilization rate of carbon dioxide gas means high use cost, and the pH can only be adjusted to 7, so that certain process requirements cannot be met.

Another way of using carbon dioxide gas to neutralize the pH value of water is to mix the water to be treated with the carbon dioxide gas through a venturi nozzle or a venturi static mixer and then add the mixed solution into the water to be treated, and the way can be added into a shallow pool and a long-distance pipeline, but the way also faces the problems of escape of CO2 small bubbles, low reaction efficiency and long reaction time.

The above-mentioned two methods of adding carbon dioxide gas are both referred to as gas adding systems because they use venturi principle to add carbon dioxide gas and mix it with treated water to adjust pH. The gas adding systems have the defects of easy escape of CO2 small bubbles, low reaction efficiency, low carbon dioxide gas utilization rate and long reaction time.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a carbonic acid solution adding system for adjusting the pH value or hardness or turbidity of water and greatly improving the utilization rate of carbon dioxide gas.

The technical conception of the invention is as follows: mixing gaseous carbon dioxide with certain pressure and temperature and reaction water with certain pressure (low pH effluent or low hardness effluent or low turbidity effluent treated by adding carbonic acid process) in a certain proportion by a Venturi static mixer to generate a gas-water mixture; then the gas-water mixture is converted into saturated carbonic acid solution through an annular coil pipe or a liquid storage tank; then changing the saturated carbonic acid solution into a supersaturated carbonic acid solution through a long-distance pipeline; finally, the supersaturated carbonic acid solution is reversely injected into the water to be treated through the diffuser, so that the carbonic acid solution and alkaline substances in the water are subjected to neutralization reaction, the purpose of adjusting the pH value of the water (or the purpose of adjusting the hardness or turbidity of the water can be achieved by reacting with CaCO3 in the water), meanwhile, the generation of bubbles can be greatly reduced, and the utilization rate of carbon dioxide gas can be greatly improved.

The invention aims at realizing the following technical scheme:

the invention relates to a carbonic acid solution adding system, which comprises a mixer and a diffuser; the device also comprises a carbon dioxide gas pipeline and a reaction water pipeline; a water pump is arranged on the reaction water pipeline; the outlet of the water pump is connected with the inlet of the mixer; the carbon dioxide gas pipeline is connected with the inlet of the mixer; an annular coil pipe or a liquid storage tank and a long-distance pipeline (straight pipe) are arranged between the outlet of the mixer and the inlet of the diffuser; the diffuser is arranged in the water to be treated; the diffuser is a hollow cylindrical object with one end open and the other end closed; a passage for releasing carbonic acid solution is formed in the cylindrical side wall of the diffuser; the passage for releasing the carbonic acid solution is a small hole or a narrow gap or a combination of the small hole and the narrow gap; the channel for releasing the carbonic acid solution can generate certain back pressure and enable the supersaturated carbonic acid solution to be sprayed into water to be treated at a certain outlet pressure (can generate back pressure of more than 3bar and enable the supersaturated carbonic acid solution to be sprayed into the water to be treated at an outlet pressure of more than 3 bar), so that a pressure difference of more than 2bar is ensured between the outlet pressure of the diffuser and the pressure of the water to be treated;

The diffuser is arranged in raw water or a water pipeline to be treated, which has water flowing, is positioned at the upstream of water flow, and a passage for releasing carbonic acid solution is arranged on one half of the side wall of the diffuser; the channels for releasing the carbonic acid solution are one or more, or one or more rows; the diffuser is inserted into raw water or a water pipeline perpendicular to the water flow direction, one side of the diffuser, which is provided with a channel for releasing carbonic acid solution, is opposite to the upstream of the water flow, so that carbonic acid solution in the diffuser can be sprayed out from the channel for releasing carbonic acid solution reversely opposite to the water flow, and the carbonic acid solution is sprayed out to react with water in a mixing way, and meanwhile, the pressure on the other side is low, so that vortex can be generated to further strengthen the mixing effect;

or the diffuser is arranged in a pool, a pond or a sewage tank which is to be treated and has no water flowing, and a plurality of or a plurality of rows of passages for releasing carbonic acid solution are arranged on the side walls of both sides of the diffuser or on the whole cylindrical side wall (one or a plurality of circles of small holes and/or narrow gaps can be arranged on the whole cylindrical side wall to realize 360-degree feeding).

Further, the inlet of the reaction water pipeline is connected with the effluent water after the water to be treated is added with carbonic acid (namely, the effluent water treated by the carbonic acid adding system and the carbonic acid adding process is used as water for a water pump, namely, reaction water), namely: the raw water or water pipeline downstream water outlet with water flowing to be treated is connected with the inlet of the water pump through a reaction water pipeline; or the water outlet of the pool, pond or sewage tank to be treated without water flow is connected with the water inlet of the water pump through a reaction water pipeline.

Further, the carbonic acid solution adding system also comprises a liquid carbon dioxide storage tank, an electronic vaporizer or a fin heat exchanger and a gas heater which are connected in sequence; or the carbonic acid solution adding system also comprises a Dewar tank or a steel cylinder and a gas heater which are sequentially connected; the outlet of the gas heater is connected with the inlet of the carbon dioxide gas pipeline.

Carbon dioxide gas gasified by an electronic carburetor or a fin heat exchanger and heated by a gas heater to a certain temperature and a certain pressure (a temperature of 30 ℃ or higher and a pressure of 3bar or higher) and pressurized reaction water pressurized by a water pump to a certain pressure (a pressure of 3bar or higher) form a gas-water mixture in a mixer; the gas-water mixture is preliminarily formed into saturated carbonic acid solution in an annular coil pipe or a liquid storage tank; the saturated carbonic acid solution forms supersaturated carbonic acid solution in a long-distance pipeline (straight pipe); the supersaturated carbonic acid solution is sprayed into the raw water or water upstream of the water flow in the water pipeline or into the water in the water basin, pond or sewage tank reversely through the passage for releasing the carbonic acid solution on the diffuser.

Further, a water quality on-line detector (a pH probe, a water hardness on-line detector, a turbidity on-line detector, etc.) is arranged at the downstream of the water flow in the raw water or the water pipeline or at the water outlet of the pool, the pond or the sewage tank, the water quality on-line detector is connected with a signal receiver, and the signal receiver is connected with the input end of the PLC controller; the output end of the PLC is connected with a carbon dioxide gas flow control valve; the water quality online detector transmits signals to the signal receiver in real time, and the opening size of the carbon dioxide gas flow control valve is controlled after the signals received by the signal receiver are processed by the PLC so as to control the dosage of the carbon dioxide gas, thereby achieving the pH value, hardness or turbidity which a user hopes to control.

Further, when the diffuser is arranged in raw water or a water pipeline to be treated, which flows with water, the diffuser is a hollow long cylindrical object with one closed end and one polygonal half of the cross section and the other circular arc, and a plurality of passages for releasing carbonic acid solution are formed in one side wall of one polygonal half of the diffuser; the passage for releasing the carbonic acid solution is one or more rows of small holes, one or more rows of narrow slits, or a combination of one or more rows of small holes and one or more rows of narrow slits (i.e. a combination of small holes and narrow slits); or may be one or more small holes, one or more narrow slits, or a combination of one or more small holes and one or more narrow slits (i.e., a combination of both small holes and narrow slits); the diffuser is inserted into the raw water perpendicular to the water flow direction, and one side of the diffuser with small holes and/or narrow gaps is/are opposite to the upstream of the water flow, so that the carbonic acid solution in the diffuser can be sprayed out from the small holes and/or narrow gaps reversely opposite to the water flow.

When the diffuser is arranged in a pool, a pond or a sewage tank which is to be treated and has no water flow, the diffuser for realizing 360-degree casting can be designed into a hollow cylinder, and can be also designed into a square cylinder with a polygonal cross section (such as square, hexagon and the like) on the premise of ensuring back pressure.

Still further, the apertures and/or slots in each row are located on the same vertical line and are uniformly aligned.

Further, a plurality of channels for releasing carbonic acid solution on the same horizontal plane are uniformly arranged with a center included angle smaller than 180 degrees; two adjacent channels for releasing carbonic acid solution on the same horizontal plane are arranged at an acute central included angle so as to ensure that the carbonic acid solution is ejected out to be mixed with water to be treated in the water flow direction at a certain outlet pressure (more than 3 bar), and the vortex strengthening mixing effect can be generated.

Further, the small holes are designed for small diameter pipes below DN25, i.e. when the long distance pipe is a small diameter pipe below DN25, the passage for releasing carbonic acid solution is one or more rows of small holes, or a combination of one or more rows of small holes and one or more rows of narrow slits; either one or more small holes or a combination of one or more small holes and one or more narrow slits. The narrow slit is more suitable for large pipe diameters larger than DN25, i.e. when the long distance pipe is a large pipe diameter larger than DN25, the passage for releasing carbonic acid solution is one or more rows of narrow slits, or a combination of one or more rows of small holes and one or more rows of narrow slits; or one or more narrow slits, or a combination of one or more apertures and one or more narrow slits.

Further, the mixer includes a venturi tube and a static mixer; the venturi has a front constriction, a middle throat and a rear expansion; the carbon dioxide gas filling port is positioned at the middle throat part of the venturi tube (carbon dioxide gas is filled into the reaction water perpendicular to the water flow direction); the inlet of the static mixer is connected with the expansion section of the venturi tube; the static mixer outlet is connected to the diffuser inlet through an annular coil or reservoir and long-distance piping.

Further, the volume ratio of carbon dioxide gas having a temperature of 30 ℃ or higher and a pressure of 3bar or higher to the reaction water is not less than 1:40. The water consumption of the water pump can be reduced by reducing the water temperature, and the water-air volume ratio of 1:1 can be achieved.

Further, the channels for releasing carbonic acid solution can generate a back pressure of more than 3bar and enable supersaturated carbonic acid solution to be sprayed into water to be treated at an outlet pressure of more than 3 bar; the diffuser back pressure was greater than 3bar and the pressure of the entire system was maintained at greater than 3bar. The saturated carbonic acid solution can be further converted into supersaturated carbonic acid solution by keeping the pressure of the system to be more than 3bar, otherwise, the utilization rate of the carbon dioxide above 97% is affected. The concentration of carbonic acid solution is more than 99% before the outlet of the diffuser, and when the carbonic acid solution passes through small holes and narrow gaps, a small amount of carbonic acid overflows from the solution in the form of bubbles due to pressure drop, so that the utilization rate of the whole carbonic acid is more than 97%.

The solubility of carbon dioxide gas is related to temperature, pressure: under the same pressure condition, the lower the temperature is, the higher the solubility is; under the same temperature condition, the higher the pressure is, the higher the solubility is; therefore, the generation of carbonic acid can be enhanced or accelerated by reducing the water temperature and improving the system pressure. According to the conditions of each use scene, such as water temperature, water pressure, water quality parameters of raw water (water to be treated), stable pH value or hardness or turbidity expected by a user, the position of a carbonic acid adding point and the like, the parameters of the water pump and the dosage of carbon dioxide gas can be selected.

By using an electronic vaporizer or a fin heat exchanger, the cryogenic liquid carbon dioxide can be vaporized to gaseous carbon dioxide using electrical heating or air heat exchange principles. The carbon dioxide in the liquid carbon dioxide storage tank is liquid carbon dioxide with the temperature below 0 ℃ and the pressure of about 17-22bar, the temperature of gaseous carbon dioxide gasified by an electronic carburetor or a fin heat exchanger is 0-10 ℃, the pressure can be adjusted to 5-10bar, the gaseous carbon dioxide is injected into reaction water from a carbon dioxide gas injection port at the venturi throat, at the moment, the water flow speed at the venturi throat is low in pressure, the carbon dioxide gas enters into a depressurization process, dry ice is generated in the depressurization process of the carbon dioxide gas, and the dissolution and the equipment efficiency of the carbon dioxide gas are influenced, so that a gas heater is needed to be additionally arranged behind the electronic carburetor or the fin heat exchanger, and the temperature of the carbon dioxide gas is increased to be more than 30 ℃ by the gas heater so as to prevent dry ice.

The formation of the saturated carbonic acid solution is initiated from the outlet of the static mixer (i.e., the formation of the saturated carbonic acid solution in the annular coil or reservoir), and is a gradual disappearance of the carbon dioxide bubbles and gradual formation of the saturated carbonic acid solution.

The working principle of the carbonic acid solution adding system of the invention is as follows: the high-pressure low-temperature liquid carbon dioxide is stored in a liquid carbon dioxide storage tank, the liquid carbon dioxide comes out from the bottom of the liquid carbon dioxide storage tank and is conveyed to an electronic vaporizer or a fin heat exchanger, and the liquid carbon dioxide is continuously and quantitatively converted into carbon dioxide gas; alternatively, the carbon dioxide gas is stored in a dewar or cylinder from which the carbon dioxide gas is released; carbon dioxide gas passes through a gas heater, and is kept at a temperature of more than 30 ℃ and a pressure of more than 3 bar; introducing carbon dioxide gas with the temperature of above 30 ℃ and the pressure of above 3bar into a mixer, pressurizing reaction water (low-pH effluent or low-hardness effluent or low-turbidity effluent treated by a carbonic acid adding process) to above 3bar by a water pump, introducing into the mixer, and mixing the carbon dioxide gas with the pressurized reaction water in the mixer to form a gas-water mixture with a certain pressure; the supersaturated carbonic acid solution is formed by the gas-water mixture through an annular coil pipe or a liquid storage tank between the mixer and the diffuser and a long-distance pipeline, and is conveyed to the diffuser, specifically: the gas-water mixture is preliminarily formed into saturated carbonic acid solution in an annular coil pipe or a liquid storage tank; the saturated carbonic acid solution forms supersaturated carbonic acid solution in a long-distance pipeline (straight pipe); the supersaturated carbonic acid solution is sprayed into the water upstream of the raw water flow or into the water in the water inlet tank through the passages (small holes and/or narrow slits) on the diffuser for releasing the carbonic acid solution; that is, the supersaturated carbonic acid solution is reversely sprayed into water through small holes and/or narrow gaps in the diffuser to form a mixed solution of the high-concentration carbonic acid solution and a small amount of carbon dioxide micro-bubbles, the carbonic acid solution meets alkaline substances in the water and starts to perform acid-base neutralization reaction, or the carbonic acid solution meets calcium ions or CaCO3 in the water to react, and the small amount of carbon dioxide micro-bubbles are absorbed by water flow so as to achieve the purposes of neutralizing acid-base or reducing the hardness of the water or reducing the turbidity of the water. The water quality on-line detector (pH probe or water hardness or turbidity on-line detector) is arranged at the downstream of the water flow in the raw water or water pipeline or at the water outlet of the pool, pond or sewage tank, and transmits signals to the signal receiver in real time, and the signal received by the signal receiver is processed by the PLC and then controls the opening of a carbon dioxide gas flow control valve to control the carbon dioxide gas dosage so as to achieve the pH, hardness or turbidity which the user wants to control.

The venturi static mixer combination set (comprising a venturi tube, a static mixer, an annular disc tube or a liquid storage tank and a long-distance pipeline) can be regarded as an integral structure, and the main function is to mix carbon dioxide gas with different pressures and reaction water to generate supersaturated carbonic acid solution. The pressurized reaction water (low pH water and the like) firstly passes through the venturi constriction section, the pressure drop flow rate is increased, the pressure of the carbon dioxide gas is higher than the pressure at the venturi throat section, the pressure difference mixes the carbon dioxide gas and the reaction water to form gas-water mixed solution, the mixed solution passes through the expansion section and then enters the static mixer, and the pressure of the mixed solution at the outlet of the expansion section is smaller than the pressure of the carbon dioxide gas inlet and larger than the inlet pressure of the reaction water. Thus, the mixed liquid can be smoothly conveyed into the static mixer for mixing. The mixed solution was thoroughly mixed by a static mixer. A long-distance pipeline and an annular coil pipe or a liquid storage tank are arranged between the diffuser with the back pressure of more than 3bar and the static mixer, and the mixture forms supersaturated carbonic acid solution in the annular coil pipe or the liquid storage tank and the long-distance pipeline, so that compared with the supersaturated carbonic acid solution, the supersaturated carbonic acid solution can reduce the generation of bubbles.

The method for reducing water temperature and increasing pressure of the system can strengthen or accelerate carbonic acid generation, for example, a water cooling system … added in the system can be provided with a water cooling system outside the annular coil pipe, a cooling liquid coil pipe is arranged in the liquid storage tank, or a cooling water pipe added in the middle lower part of the liquid storage tank is arranged.

The liquid carbon dioxide is gasified and warmed to prevent dry ice from being generated. The dry ice can be prevented from being generated even without the heating devices in a high-temperature environment. The method of utilizing venturi gas-water is not limited to the venturi form herein.

The invention has the beneficial effects that:

the invention provides a complete liquid carbonic acid adding system, which prepares supersaturated carbonic acid solution by gaseous carbon dioxide and reaction water in advance, and adds the supersaturated carbonic acid solution into water through a diffuser, thereby adjusting the pH value or hardness or turbidity of the water.

Compared with the prior art, the carbonic acid solution adding system has the following advantages:

1) Firstly, mixing carbon dioxide gas with certain pressure and heating with pressurized reaction water through a Venturi static mixer device, forming a gas-water mixture with pressure caused by different pressures through the Venturi static mixer, and converting the gas-water mixture into saturated carbonic acid solution through an annular coil pipe or a liquid storage tank; forming a supersaturated carbonic acid solution in the long-distance pipeline by the saturated carbonic acid solution; the supersaturated carbonic acid solution is put into water through a diffuser; since the pressure of the water is in a low pressure state, in order to avoid a great deal of escape of carbon dioxide bubbles in the mixed liquor in the pressure drop, the invention designs the diffuser, and the function of the diffuser is to stabilize the pressure of the system, maintain the back pressure of the system and inject carbonic acid solution into the treated water. The supersaturated carbonic acid solution is sprayed out through the small holes of the diffuser, and then acid-base neutralization reaction is carried out on the supersaturated carbonic acid solution and alkaline substances in water. Because of the pressure drop, a small amount of carbon dioxide bubbles escape from the carbonic acid solution, so that the small amount of carbon dioxide bubbles and the high-concentration carbonic acid solution are ejected together to generate strong vortex with water, the reaction speed is increased, and the reaction time is shortened. Through application of test cases, the gas-water mixture or the mixed solution is converted into supersaturated carbonic acid solution (the concentration of carbonic acid is more than 99%, the effective utilization rate of carbon dioxide gas is more than 97%), the reaction of the carbonic acid solution and water is liquid-liquid reaction, the neutralization reaction time is completed within 20-30 seconds, the minimum pH value can reach 5, and the pH fluctuation can be accurately and stably controlled. Compared with the carbon dioxide adding mode, the invention does not need an additional reaction tank, has high carbon dioxide utilization rate and greatly reduces the use cost of users.

2) In the prior art, a mode of adding carbon dioxide gas is used, a venturi nozzle or a venturi static mixer is a component for projecting the gas into water, and the gas and the water are mixed at a constriction section or a throat pipe of the venturi nozzle and then are emitted through a dilation section. The injection speed of the solution is increased, the pressure is rapidly reduced, a large amount of carbon dioxide gas is separated out from the solution to form large bubbles, and only a small part of carbon dioxide gas reacts with water to generate carbonic acid. Because the pressure in the water is different at different heights, carbon dioxide bubbles escape from the water in open environments such as shallow ponds, water pools and the like; carbon dioxide bubbles in the pipeline can collapse, cause vibration and cavitation, and affect the accuracy of the pH.

The main function of the diffuser in the invention is to stabilize the pressure of the whole system to be more than 3bar by using small holes and/or narrow slits as shown in the figure, always seal the carbon dioxide gas in the supersaturated carbonic acid solution, and generate stable carbonic acid solution and a small amount of carbon dioxide bubbles when the pressure is released. A passage for releasing carbonic acid solution is formed in one half of the side wall of the diffuser, and the passage for releasing carbonic acid solution is one or more rows of small holes, one or more rows of narrow gaps, or two combinations of the small holes and/or the narrow gaps; a plurality of channels for releasing carbonic acid solution on the same horizontal plane are uniformly arranged at a center included angle smaller than 180 degrees; two adjacent channels for releasing carbonic acid solution on the same horizontal plane are arranged at an acute central included angle so as to ensure that the outlet pressure of the carbonic acid solution is more than 3bar to be ejected and mixed with water. The inlet pressure and the outlet pressure of the pressure mixture (ideal) are identical through small holes and/or narrow slits and are injected into the water at a very fast rate. Because the pressure drops, partial carbon dioxide gas can escape from the solution in the form of micro bubbles due to the pressure difference, so that the mixed solution of carbonic acid solution and micro bubbles is sprayed together to be mixed with water, and meanwhile, because the small holes and/or narrow gaps on each row are positioned on the same vertical line and are uniformly arranged, the pressure difference between the side with holes of the diffuser and the side without holes is formed, the pressure mixed solution forms vortex in the water, and the acid-base neutralization reaction is further accelerated.

In the present invention, a diffuser for spraying a carbonic acid solution, a narrow slit and a small hole are used in combination or alone, and the small hole or the combination of the narrow slit and the small hole is designed for a small-pipe diameter pipe having a DN25 or less; the narrow gap or the combination of the narrow gap and the small hole is more suitable for large-diameter pipelines larger than DN 25; the contact surface between the solution ejected through the narrow gap and water is larger than that of the solution ejected through the small hole; depending on the use scenario, a combined design of small holes and/or narrow slits is also applied. The liquid flowing through the small holes is a process of shrinkage and re-diffusion, the state of the liquid is turbulent, great pressure loss is generated, and more carbon dioxide gas is separated out due to the excessive small holes. Compared to small holes, the state of the liquid passing through the narrow gap and the pressure being lower than 10bar is a laminar flow, where the carbon dioxide is precipitated much less than in small holes. However, in some cases, small holes and narrow slits are combined, and a small amount of carbon dioxide gas is required to be lost, so that a certain turbulence is formed, and the mixing effect with raw water is enhanced. Compared with the small holes, the narrow gap can solve the problem that the small holes deform due to cavitation and influence the solution ejection flow and pressure in the use of the system.

Compared with a Venturi nozzle or a Venturi static mixer in the prior art, the carbonic acid solution diffuser solves the problems of low utilization rate (dissolution rate) of carbon dioxide gas, noise, vibration, cavitation and the like; meanwhile, the application scene range of adding the carbonic acid solution is wider, and the carbonic acid solution can be applied to natural lakes, shallow ditches, shallow ponds, pipelines, liquid tanks and the like.

3) The invention solves the problems that gas and water with different pressures are mixed by the mixer, the gas is easy to separate out from the liquid, the bubbles in the solution of the static mixer are cut into micro bubbles, and compared with the macro bubbles, the micro bubbles are more easy to dissolve in the water, so as to generate carbonic acid solution. On the other hand, the pressure and time required for converting the gas-water mixture into supersaturated carbonic acid solution, too long or too short a pipe distance between the diffuser and the static mixer, too large or too small a pipe diameter, will create problems of system pressure drop, carbon dioxide bubble precipitation or injection of the mixture into the water without converting the mixture into carbonic acid solution, and the design of the annular coil or the liquid storage tank solves these problems, and the carbonic acid solution remains stable in the closed pressure environment.

Drawings

FIG. 1 is a schematic diagram of the overall structure of a carbonic acid solution feeding system according to the present invention;

FIG. 2 is a schematic diagram of the front view of the mixer 5+ toroidal coil 14 of the present invention;

fig. 3 is a schematic diagram showing the front view of the mixer 5+ tank 15 according to the present invention;

fig. 4 is an enlarged view of a portion of the diffuser 6 of fig. 3;

FIG. 5 is a schematic cross-sectional top view of a diffuser 6 of the present invention;

fig. 6 is a schematic front view of the diffuser 6 according to the present invention;

fig. 7 is a schematic side view of the diffuser 6 according to the present invention.

In the figure: 1. liquid carbon dioxide storage tank 2, electronic carburetor 3, gas heater 4, water pump 5, mixer 6, diffuser 7, pH probe 8, narrow slit 9, small hole 10, contraction section 11, carbon dioxide gas filler 12, expansion section 13, static mixer 14, annular coil 15, liquid storage tank 17, long-distance pipeline 18, signal receiver 19, outer side wall 20, inner side wall A, center angle B

Detailed Description

The invention is further described below with reference to the drawings and examples.

Example 1

As shown in fig. 1, the carbonic acid solution adding system for adjusting the pH value of water according to the present embodiment includes a liquid carbon dioxide storage tank 1, an electronic vaporizer 2, a gas heater 3, a mixer 5, a diffuser 6, and a water pump 4 connected to an inlet of the mixer 5; an annular coil 14 and a long-distance pipe 17 (straight pipe) are arranged between the mixer 5 and the diffuser 6; the diffuser 6 is arranged in a water pipeline to be treated, which is provided with water flow, is positioned at the upstream of water flow, and is inserted into the water pipeline perpendicular to the water flow direction; a plurality of carbonic acid solution releasing channels are formed on one half of the side wall of the diffuser 6, and can generate back pressure of more than 3bar and enable supersaturated carbonic acid solution to be sprayed into water to be treated (reversely sprayed into water upstream of water flow) at an outlet pressure of more than 3bar, so that a pressure difference of more than 2bar exists between the outlet pressure of the diffuser and the pressure of the water to be treated; the downstream water outlet of the water pipeline with water flow to be treated is connected with the inlet of the water pump 4 through a reaction water pipeline 11 (the low pH water outlet treated by the carbonic acid adding system and the carbonic acid adding process is used as water for the water pump 4, namely reaction water); a carbon dioxide gas vaporized by the electronic vaporizer 2 and heated by the gas heater 3 to a temperature of 30 ℃ or higher and a pressure of 3bar or higher and pressurized reaction water pressurized by the water pump to a pressure of 3bar or higher form a gas-water mixture in the mixer 5; the mixture of air and water forms saturated carbonic acid solution in the annular coil 14 preliminarily; the saturated carbonic acid solution forms a supersaturated carbonic acid solution in the long-distance pipe 17 (straight pipe); the supersaturated carbonic acid solution is sprayed back into the water upstream of the water flow in the water inlet conduit through the channels on the diffuser 6 that release the carbonic acid solution. A pH probe 7 is arranged at the downstream of water flow in a water pipeline, the pH probe 7 is connected with a signal receiver 18, and the signal receiver 18 is connected with the input end of the PLC controller; the output end of the PLC is connected with a carbon dioxide gas flow meter arranged at the outlet of the electronic carburetor 2; the pH probe 7 transmits signals to the signal receiver 18 in real time, and the signals received by the signal receiver 18 are processed by the PLC to control the opening of the switch of the carbon dioxide gas flow meter so as to control the dosage of the carbon dioxide gas, thereby achieving the pH value which a user hopes to control.

As shown in fig. 5-7, the diffuser 6 is a hollow long cylindrical object with one closed end and one polygonal half and one circular arc-shaped half, and a plurality of passages for releasing carbonic acid solution are formed on one half side wall of one polygonal side of the diffuser 6; the passage for releasing the carbonic acid solution is a combination of small holes and narrow gaps, a row of small holes 9 are arranged in the middle, and a row of narrow gaps 8 are respectively arranged at two sides; two adjacent passages (small holes 9 and/or narrow slits 8) for releasing carbonic acid solution on the same horizontal plane are arranged at an acute central included angle (i.e. the central included angle formed by the connection of the two adjacent passages for releasing carbonic acid solution and the central point is an acute angle, as A, B in figure 5, the two central included angles are both acute angles) so as to ensure that the carbonic acid solution is ejected to be mixed with water to be treated with an outlet pressure of more than 3bar against the water flow direction and can be mixed with the water to be treated

As shown in fig. 1 and 7, the diffuser 6 is arranged in the water pipe to be treated, which has water flowing, upstream of the water flow; the diffuser 6 is inserted into the water pipeline perpendicular to the water flow direction, one side of the diffuser 6 provided with the small holes 9 and the narrow gaps 8 is opposite to the upstream of the water flow, so that the carbonic acid solution in the diffuser 6 can be reversely sprayed out of the small holes 9 and the narrow gaps 8 to the water flow, and the carbonic acid solution is sprayed out to react with the water in a mixing way, and meanwhile, the pressure on the other side is low, so that vortex can be generated to further strengthen the mixing effect.

The small holes 9 and the narrow slits 8 in the diffuser 6 can generate a back pressure of more than 3bar and enable the supersaturated carbonic acid solution to be sprayed into the water to be treated in the water pipeline at an outlet pressure of more than 3bar (reversely sprayed into the water upstream of the water flow), so that a pressure difference of more than 2bar is ensured between the outlet pressure of the diffuser 6 and the pressure of the water to be treated.

The length of the long-distance pipe 17 (straight pipe) is within a reasonable range, and the residence time of the saturated carbonic acid solution in the long-distance pipe 17 is 5 seconds or more, because the saturated carbonic acid solution needs to be retained in the pipe for 5 seconds or more to form a supersaturated carbonic acid solution. If the length of the long-distance pipe 17 is too short, the residence time of the saturated carbonic acid solution in the long-distance pipe 17 is too short, and it is impossible to form a supersaturated carbonic acid solution, and only a saturated carbonic acid solution or a mixed solution can be formed. If the length of the long-distance pipe 17 is too long, there will be a pressure drop in the long pipe, the larger the pressure drop, the more small bubbles of CO2 will be generated and will be separated out of the solution, and the solution will return to the original gas-water state.

As shown in fig. 2, 3, 4, the mixer 5 (venturi static mixer) comprises a venturi tube and a static mixer 13; the venturi has a front constriction 10, an intermediate throat and a rear expansion 12; the carbon dioxide gas filling port 11 is positioned at the middle throat part of the venturi tube (carbon dioxide gas is injected into low pH water perpendicular to the water flow direction); the inlet of the static mixer 13 is connected with the expansion section 12 of the venturi tube; the outlet of static mixer 13 is connected to the inlet of diffuser 6 by annular coil 14 or reservoir 15 and long distance conduit 17.

The pH values of the raw water and the water to be treated are unstable and fluctuate between 8 and 12, after the carbonic acid is added in the carbonic acid adding process, the pH can be reduced and stabilized at the low pH required by customers, and the low pH effluent which is treated by the carbonic acid adding process and is stabilized at the low pH required by customers is used as water for a water pump. Such as: the pH of raw water in a tap water plant fluctuates between 8 and 9, the pH required by customers is 7, and low pH effluent water which is treated by the carbonic acid processing technique of the present invention and is stabilized at pH 7 is used as water for the water pump 4 (reaction water). The pH of the printing and dyeing wastewater fluctuates between 9 and 12, the pH required by customers is 8.5, the pH of the effluent water treated by the carbonic acid processing technology can be stabilized at 8.5, and the low pH effluent water treated by the carbonic acid processing technology and stabilized at 8.5 is used as water for a water pump 4 (reaction water). The pH value of the water to be treated is unstable, the pH value is stable after carbonic acid is added, and the water with the stable pH value can reduce the adding amount of carbon dioxide in the next batch of water to be treated if the carbon dioxide is contained in the water after carbonic acid is added. The method is a process of recycling carbon dioxide, ensures the pH stability of the effluent, and uses as little carbon dioxide gas as possible.

The working principle of the carbonic acid solution adding system of this embodiment is as follows: the high-pressure low-temperature liquid carbon dioxide is stored in the liquid carbon dioxide storage tank 1; the liquid carbon dioxide comes out of the bottom of the liquid carbon dioxide storage tank 1 and is conveyed to the electronic carburetor 2, and the liquid carbon dioxide is continuously and quantitatively converted into carbon dioxide gas; carbon dioxide gas passes through a gas heater 3, and is kept at a temperature of more than 30 ℃ and a pressure of more than 3 bar; carbon dioxide gas with the temperature of above 30 ℃ and the pressure of above 3bar enters the mixer 5, and meanwhile, reaction water (low-pH effluent water treated by adding carbonic acid process) enters the mixer 5 after being pressurized to above 3bar by the water pump 4; the volume ratio of carbon dioxide gas having a temperature of 30 ℃ or higher and a pressure of 3bar or higher to low pH water is 1:40, a step of performing a; in the mixer 5, carbon dioxide gas is mixed with pressurized reaction water to form a gas-water mixture with a certain pressure; the gas-water mixture forms supersaturated carbonic acid solution through a pipeline (an annular coil 14 and a long-distance pipeline 17) between the mixer 5 and the diffuser 6, the supersaturated carbonic acid solution is conveyed to the diffuser 6, the supersaturated carbonic acid solution forms a mixed solution of high-concentration carbonic acid solution and a small amount of carbon dioxide microbubbles through small holes 9 and narrow slits 8 on the diffuser 6 and is reversely sprayed into water, the carbonic acid solution meets alkaline substances in the water and starts to perform acid-base neutralization reaction, so that the purpose of neutralizing the acid-base is achieved, and the small amount of carbon dioxide microbubbles are absorbed by water flow; the pH probe 7 is arranged at the downstream of the water flow in the water pipeline and transmits a signal to the signal receiver 18 in real time, and the signal received by the signal receiver 18 is processed by the PLC and then controls the opening of a carbon dioxide flow control valve to control the carbon dioxide dosing amount so as to achieve the pH value which the user wants to control.

Firstly, mixing carbon dioxide gas with certain pressure and heating with pressurized reaction water through a venturi tube, forming a gas-water mixture with pressure through a static mixer, and converting the gas-water mixture into saturated carbonic acid solution through an annular coil 14 or a liquid storage tank 15; the saturated carbonic acid solution forms a supersaturated carbonic acid solution in the long distance of pipe 17; the supersaturated carbonic acid solution is put into water through a diffuser 6 (shown in fig. 5-7); since the pressure of the water is low, the present invention contemplates this diffuser 6 (shown in fig. 5-7) in order to avoid a large escape of carbon dioxide bubbles in the mixed liquor in the pressure drop, the function of this diffuser 6 being to stabilize the pressure of the system, maintain the back pressure of the system and inject the carbonic acid solution into the treated water. The supersaturated carbonic acid solution is sprayed out through the small holes 9 and the narrow slits 8 on the diffuser 6, and acid-base neutralization reaction is carried out on the supersaturated carbonic acid solution and alkaline substances in water. Because of the pressure drop, a small amount of carbon dioxide bubbles escape from the carbonic acid solution, so that the small amount of carbon dioxide bubbles and the carbonic acid solution are ejected together and strongly vortex with water, the reaction speed is increased, and the reaction time is shortened. Through application of test cases, the gas-water mixture or the mixed solution is converted into supersaturated carbonic acid solution (the concentration of carbonic acid is more than 99%, the effective utilization rate of carbon dioxide is more than 97%), the acid-base neutralization reaction between the carbonic acid solution and alkaline substances in water is a liquid-liquid reaction, the neutralization reaction time is completed within 20-30 seconds, the minimum pH value can reach 5, and the pH fluctuation can be accurately and stably controlled. Compared with the carbon dioxide adding mode, the invention does not need an additional reaction tank, has high carbon dioxide utilization rate and greatly reduces the use cost of users.

As shown in fig. 2 and 3, carbon dioxide gas with a certain pressure and a certain temperature is injected into reaction water with a pressure lower than that of the carbon dioxide gas through a venturi tube (the reaction water can use low-pH factory water which is treated by a carbonic acid adding process and is subjected to coagulating sedimentation filtration to remove impurities so as to prevent the impurities from being mixed into a static mixer 13 and generating unnecessary cleaning maintenance), and the air-water mixture achieves better dispersion and mixing purposes of carbon dioxide bubbles through the static mixer 13. Further, the static mixer 13 is connected with the diffuser 6 through the annular coil 14 or the liquid storage tank 15 and a long-distance pipeline (straight pipe) 17, and the back pressure of the small holes and/or narrow slits on the diffuser 6 is kept to be more than 3bar, so that the gas-water mixture is converted into a carbonic acid solution and kept in a supersaturated state, supersaturated carbonic acid solution is sprayed into water to be treated through the small holes and/or narrow slits on the diffuser 6, and the carbonic acid solution can be quickly reacted with alkaline substances in the water while carbon dioxide bubbles are absorbed by water vortex flow, so that the purpose of neutralizing the pH value is achieved.

The gas-water mixture passes through the annular coil 14, the pressure of the outer side wall 19 of the annular coil 14 is greater than the pressure of the inner side wall 20, the carbon dioxide bubbles are gradually dissolved into water under the action of the continuous pressure difference, a saturated carbonic acid solution is further formed, the supersaturated carbonic acid solution is sent to the diffuser 6 through the long-distance pipeline 17, and meanwhile, the back pressure of the diffuser 6 maintains the whole conversion process and pipeline pressure, so that the escape of the carbon dioxide bubbles from the carbonic acid solution caused by the pressure drop can be prevented, and the return of the carbonic acid solution to the gas-water mixture state is prevented.

The gas-water mixed supersaturated carbonic acid solution forming device (comprising a venturi tube, a static mixer 13, an annular coil 14 and a long-distance pipeline 17) can be regarded as an integral structure, and the main function is to mix carbon dioxide gas with different pressures and low-pH water to prepare the supersaturated carbonic acid solution. As shown in fig. 2 and 3, when the pressurized low pH water first enters the venturi constriction 10 and passes through the throat portion, the pressure drop flow rate increases, the pressure of the carbon dioxide gas is higher than the pressure at the throat portion, the pressure difference mixes the carbon dioxide gas and the low pH water to form a gas-water mixed solution, the mixed solution passes through the expansion section 12 and then enters the static mixer 13, and the pressure of the mixed solution at the outlet of the expansion section 12 is lower than the pressure of the carbon dioxide gas and is higher than the inlet pressure of the low pH water. In this way, the mixed liquid can be smoothly conveyed to the static mixer 13 for mixing. The mixed solution is thoroughly mixed by the static mixer 13. Between the diffuser 6 with a back pressure of 3bar or more and the static mixer 13, there are provided an annular coil 14 and a long-distance pipe, the mixture forming a saturated carbonic acid solution in the annular coil 14, the mixture forming a supersaturated carbonic acid solution in the long-distance pipe 17, the supersaturated carbonic acid solution being more capable of reducing the generation of bubbles than the saturated carbonic acid solution.

The diffuser 6 is a hollow polygonal long cylindrical object with one closed end, and is inserted perpendicular to the water flow direction, one surface of the diffuser 6 with small holes 9 and/or narrow slits 8 faces the upstream of the water flow (see fig. 7), and an opening (one end which is not closed) at the top end of the diffuser 6 can allow supersaturated carbonic acid solution to enter, and the supersaturated carbonic acid solution is mixed with the water after being sprayed from the small holes 9 and/or the narrow slits 8 reversely against the water flow. The process of the solution entering the water is a depressurization process, in which the carbonic acid pressure solution and a small amount of carbon dioxide bubbles form vortex with the upstream of the water flow and the downstream of the water flow at the moment of injection through the small holes 9 and/or the narrow slits 8, the small bubbles are absorbed by the water flow, and the carbonic acid solution reacts with the water, and the whole process is a process of intensified mixing and rapid neutralization reaction.

Role of the diffuser 6: in addition to injecting the carbonic acid solution into the water, while maintaining the pressure of the entire system, escape of carbon dioxide gas from the carbonic acid solution is prevented. The back pressure of the system is kept to be more than 3bar by the small holes 9 and the narrow gaps 8 on the diffuser 6, the supersaturated carbonic acid solution is reversely sprayed into water to be treated through the small holes 9 and the narrow gaps 8 on the diffuser 6, and the carbonic acid solution can rapidly react with alkaline substances in the water while carbon dioxide bubbles are absorbed by water vortex, so that the purpose of neutralizing the pH value is achieved. This system back pressure will maintain the overall conversion process and pipeline pressure and will prevent carbon dioxide bubbles from escaping from the carbonic acid solution due to the pressure drop and prevent the carbonic acid solution from returning to the gas-water mixture state.

In summary, the invention provides a complete carbonic acid solution adding system, which mixes gaseous carbon dioxide and low pH water in advance to prepare supersaturated carbonic acid solution, and adds the supersaturated carbonic acid solution into water through a diffuser so as to adjust the pH of the water.

In the prior art, a mode of adding carbon dioxide gas is used, a venturi nozzle is a component for projecting gas into water, and the gas and the water are mixed at a constriction section or a throat pipe of the venturi nozzle and then are ejected through an expansion section. The injection speed of the solution is increased, the pressure is rapidly reduced, a large amount of carbon dioxide gas is separated out from the solution to form atmospheric bubbles, and only a small part of the carbon dioxide gas reacts with water to generate carbonic acid. Because the pressure in the water is different at different heights, carbon dioxide bubbles escape from the water in open environments such as shallow ponds, water pools and the like; carbon dioxide bubbles in the pipeline can be broken or directly enter raw water, and only a small part of carbon dioxide participates in the neutralization reaction, so that the pH control accuracy is affected, and meanwhile, vibration and cavitation of the pipeline are caused.

The main function of the diffuser 6 in the present invention is to stabilize the pressure of the whole system above 3bar by means of the small holes 9 and the narrow slits 8 shown in fig. 5-7, to always seal the carbon dioxide gas in the supersaturated carbonic acid solution, and to generate a stable carbonic acid solution and a small amount of carbon dioxide bubbles when the pressure is released. As shown in fig. 5-7, a passage for releasing carbonic acid solution is formed on one half of the side wall of the diffuser 6, and the passage for releasing carbonic acid solution is a combination of one row of small holes 9 and a plurality of rows of narrow gaps 8 (two combinations of small holes and narrow gaps); a plurality of channels for releasing carbonic acid solution on the same horizontal plane are uniformly arranged at a center included angle smaller than 180 degrees; two adjacent channels for releasing carbonic acid solution on the same horizontal plane are arranged at an acute central included angle to ensure that the outlet pressure of the carbonic acid solution is more than 3bar to be ejected and mixed with water. Through the small holes 9 and the narrow slits 8, the inlet pressure and the outlet pressure of the pressure mixture (ideal) are identical and injected into the water at a very fast speed. Because the pressure drops, partial carbon dioxide gas can escape from the solution in the form of micro bubbles due to the pressure difference, so that the mixed solution of carbonic acid solution and micro bubbles is sprayed together to be mixed with water, and meanwhile, because the small holes 9 or the narrow gaps 8 on each row are positioned on the same vertical line and are uniformly arranged, the pressure difference exists between the side with holes and the side without holes of the diffuser 6, and the pressure mixed solution forms vortex in the water, so that the acid-base neutralization reaction is further accelerated.

Compared with the Venturi nozzle in the prior art, the carbonic acid solution diffuser 6 solves the problems of low utilization rate (dissolution rate) of carbon dioxide gas, noise, vibration, cavitation and the like; meanwhile, the application scene range of adding the carbonic acid solution is wider, and the carbonic acid solution can be applied to natural lakes, shallow ditches, shallow ponds, pipelines, liquid tanks and the like.

Example 2

As shown in fig. 2, the method for adding carbonic acid by using the small carbonic acid solution adding system in this embodiment is basically the same as the method for adding carbonic acid by using the small carbonic acid solution adding system in embodiment 1; the difference is that: the diffuser 6 is arranged in a water pool to be treated without water flow, and a plurality of passages for releasing carbonic acid solution are arranged on the side walls of both sides of the diffuser 6; the passages for releasing the carbonic acid solution are a combination of small holes and narrow gaps.

As shown in fig. 2, the diffuser 6 is arranged in a pool to be treated without water flow, and a plurality of circles of small holes and narrow slits (a row of small holes 9 and a row of narrow slits 8 are staggered) are formed on the whole cylindrical side wall of the diffuser 6, so that 360-degree throwing is realized.

The channels (small holes 9 and narrow slits 8) for releasing carbonic acid solution can generate back pressure of more than 3bar and enable the supersaturated carbonic acid solution to be sprayed into water to be treated in the water tank at an outlet pressure of more than 3bar, so that a pressure difference of more than 2bar is ensured between the outlet pressure of the diffuser and the pressure of the water to be treated.

The water outlet of the water pool which is to be treated and has no water flow is connected with the inlet of the water pump 4 through a reaction water pipeline 11 (the low pH effluent water treated by the carbonic acid adding system and the carbonic acid adding process is used as water for the water pump 4, namely reaction water).

The working principle of the carbonic acid solution adding system of this embodiment is as follows: the carbon dioxide gas vaporized by the electronic vaporizer 2 and heated by the gas heater 3 to have a temperature of 30 ℃ or higher and a pressure of 3bar or higher and the pressurized reaction water pressurized to a pressure of 3bar or higher by the water pump 4 form a gas-water mixture in the mixer 5; the mixture of air and water forms saturated carbonic acid solution in the annular coil 14 preliminarily; the saturated carbonic acid solution forms a supersaturated carbonic acid solution in the long-distance pipe 17 (straight pipe); the supersaturated carbonic acid solution is sprayed into the water in the water tank through the passages (small holes 9 and narrow slits 8) on the diffuser 6 for releasing the carbonic acid solution; a pH probe 7 is arranged at the water outlet of the water tank, the pH probe 7 is connected with a signal receiver, and the signal receiver is connected with the input end of the PLC; the output end of the PLC is connected with the control valve 14; the pH probe transmits signals to the signal receiver in real time, and the signal received by the signal receiver is processed by the PLC to control the opening of the control valve 14 so as to control the dosage of the carbonic acid solution, thereby achieving the pH value which the user wants to control.

Example 3

The carbonic acid solution addition system of this example is substantially the same as that of example 1; the difference is that: a liquid storage tank 15 and a long-distance pipe 17 (straight pipe) are provided between the mixer 5 and the diffuser 6. The long-distance pipeline 17 is a large-diameter pipeline larger than DN25, the passage for releasing carbonic acid solution is a narrow gap 8, a row of narrow gaps 8 are arranged in the middle, and a row of narrow gaps 8 are arranged on two sides.

The pressure gas-water mixture enters the liquid storage tank 15, and the gas-water mixture continuously acts on the pressure generated by the tank wall and the reaction force of the tank wall to dissolve carbon dioxide bubbles in water, so that supersaturated carbonic acid solution is finally formed. The supersaturated carbonic acid solution is fed to the diffuser 6 through a long distance of piping 17 (straight pipe) while the back pressure of the diffuser 6 will maintain the whole conversion process and piping pressure, preventing carbon dioxide bubbles from escaping from the carbonic acid solution due to the pressure drop, preventing the carbonic acid solution from returning to the gas-water mixture state.

The working principle of the carbonic acid solution adding system of this embodiment is as follows: the high-pressure low-temperature liquid carbon dioxide is stored in the liquid carbon dioxide storage tank 1; the liquid carbon dioxide comes out of the bottom of the liquid carbon dioxide storage tank 1 and is conveyed to the electronic carburetor 2, and the liquid carbon dioxide is continuously and quantitatively converted into carbon dioxide gas; carbon dioxide gas passes through a gas heater 3, and is kept at a temperature of more than 30 ℃ and a pressure of more than 3 bar; carbon dioxide gas with the temperature of above 30 ℃ and the pressure of above 3bar enters a mixer 5, meanwhile, water (low-pH effluent water treated by adding carbonic acid process) is pressurized to above 3bar by a water pump 4 and then enters the mixer 5, and in the mixer 5, the carbon dioxide gas is mixed with pressurized reaction water to form a gas-water mixture with certain pressure; the gas-water mixture is made into supersaturated carbonic acid solution through a liquid storage tank 15 between the mixer 5 and the diffuser 6 and a long-distance pipeline 17, the supersaturated carbonic acid solution is conveyed to the diffuser 6, the supersaturated carbonic acid solution forms a mixed solution of high-concentration carbonic acid solution and a small amount of carbon dioxide microbubbles through small holes and/or narrow gaps in the diffuser 6 and is reversely sprayed into water, the carbonic acid solution meets alkaline substances in the water and starts to perform acid-base neutralization reaction, so that the purpose of neutralizing acid-base is achieved, and the small amount of carbon dioxide microbubbles are absorbed by water flow; the pH probe 7 is arranged at the downstream of the water flow and transmits a signal to the signal receiver 18 in real time, and the signal received by the signal receiver 18 is processed by the PLC and then controls a carbon dioxide gas flow meter to control the carbon dioxide gas dosage so as to achieve the pH value which the user wants to control.

Firstly, mixing carbon dioxide gas with certain pressure and heating with pressurized reaction water through a venturi tube, forming a gas-water mixture with pressure through a static mixer, and converting the gas-water mixture into saturated carbonic acid solution through a liquid storage tank 15; forming a supersaturated carbonic acid solution in the long-distance pipeline by the saturated carbonic acid solution; the supersaturated carbonic acid solution is put into water through a diffuser 6 (shown in fig. 5-7); since the pressure of the water is low, the present invention contemplates this diffuser 6 (shown in fig. 5-7) in order to avoid a significant escape of carbon dioxide bubbles in the mixed liquor in the pressure drop, the function of this diffuser 6 being to stabilize the pressure of the system, maintain the back pressure of the system and inject the carbonic acid solution into the treated water. The supersaturated carbonic acid solution is sprayed out through the small holes of the diffuser 6, and acid-base neutralization reaction is carried out on the supersaturated carbonic acid solution and alkaline substances in water. Because of the pressure drop, a small amount of carbon dioxide bubbles escape from the carbonic acid solution, so that the small amount of carbon dioxide bubbles and the carbonic acid solution are ejected together to generate strong vortex with water, the reaction speed is increased, and the reaction time is shortened. Through application of test cases, the gas-water mixture or the mixed solution is converted into supersaturated carbonic acid solution (the concentration of carbonic acid is more than 99%, the effective utilization rate of carbon dioxide is more than 97%), the acid-base neutralization reaction of the carbonic acid solution and alkaline substances in water is liquid-liquid reaction, the neutralization reaction time is completed within 20-30 seconds, the minimum pH value can reach 5, and the pH fluctuation can be accurately and stably controlled. Compared with the adding mode of carbon dioxide gas, the invention does not need an additional reaction tank, has high carbon dioxide gas utilization rate and greatly reduces the use cost of users.

As shown in fig. 2 and 3, carbon dioxide gas with a certain pressure and a certain temperature is injected into reaction water with a pressure lower than that of the carbon dioxide gas through a venturi tube (the reaction water can use low-pH factory water which is treated by a carbonic acid adding process and is subjected to coagulating sedimentation filtration to remove impurities so as to prevent the impurities from being mixed into a static mixer 13 and generating unnecessary cleaning maintenance), and the air-water mixture achieves better dispersion and mixing purposes of carbon dioxide bubbles through the static mixer 13. Further, the static mixer 13 is connected with the diffuser 6 through the liquid storage tank 15 and a long-distance pipeline (straight pipe), and the back pressure of the small holes and/or narrow gaps on the diffuser 6 is greater than 3bar, so that the gas-water mixture is converted into a carbonic acid solution and kept in a supersaturated state, the supersaturated carbonic acid solution is sprayed into water to be treated through the small holes and/or narrow gaps on the diffuser 6, and the carbonic acid solution can rapidly react with alkaline substances in the water while carbon dioxide bubbles are absorbed by water vortex, so that the purpose of neutralizing the pH value is achieved.

The gas-water mixed supersaturated carbonic acid solution forming device (comprising a venturi tube, a static mixer 13, a liquid storage tank 15 and a long-distance pipeline 17) can be regarded as an integral structure, and the main function is to mix carbon dioxide gas with different pressures and low pH water to generate supersaturated carbonic acid solution. As shown in fig. 2 and 3, when the pressurized low pH water (effluent) first enters the venturi constriction 10 and passes through the throat portion, the pressure drop flow rate increases, the pressure of the carbon dioxide gas is higher than the pressure at the throat portion, the pressure difference mixes the carbon dioxide gas and the low pH water to form a gas-water mixed solution, the mixed solution passes through the expansion section 12 and then enters the static mixer 13, and the pressure of the mixed solution at the outlet of the expansion section 12 is lower than the inlet pressure of the carbon dioxide gas and higher than the inlet pressure of the low pH water. This allows the mixture to be fed to the static mixer 13 for mixing. The mixed solution is thoroughly mixed by the static mixer 13. A liquid storage tank 15 and a long-distance pipeline are arranged between the diffuser 6 with the back pressure of more than 3bar and the static mixer 13, the mixture forms saturated carbonic acid solution in the liquid storage tank 15, and the mixture forms supersaturated carbonic acid solution in the long-distance pipeline 17, so that compared with the saturated carbonic acid solution, the supersaturated carbonic acid solution can reduce the generation of bubbles.

Example 4

The carbonic acid solution addition system of this example is substantially the same as that of example 1; the difference is that: the electronic carburetor 2 is replaced by a fin heat exchanger, and the carbon dioxide gas is heated to a temperature of more than 20 ℃ through the fin heat exchanger; the long-distance pipeline 17 is a small-diameter pipeline with DN25, the passage for releasing carbonic acid solution is a combination of small holes and narrow gaps, a row of narrow gaps 8 are arranged in the middle, and a row of small holes 9 are arranged on two sides.

Example 5

The carbonic acid solution addition system of this example is substantially the same as that of example 1; the difference is that: the liquid carbon dioxide storage tank 1 and the electronic vaporizer 2 are not replaced by dewar or steel cylinders. Carbon dioxide gas is discharged from a Dewar tank or a steel cylinder, is heated to a temperature of more than 30 ℃ and a pressure of more than 3bar by a gas heater 3, and then forms a gas-water mixture with pressurized reaction water which is pressurized to the pressure of more than 3bar by a water pump 4 in a mixer 5; the mixture of air and water forms saturated carbonic acid solution in the annular coil 14 preliminarily; the saturated carbonic acid solution forms supersaturated carbonic acid solution in a long-distance pipeline 17 and is conveyed to the diffuser 6, the supersaturated carbonic acid solution forms a mixed solution of high-concentration carbonic acid solution and a small amount of carbon dioxide microbubbles through small holes and/or narrow gaps in the diffuser 6 and is reversely sprayed into water, the carbonic acid solution meets alkaline substances in the water and starts to perform acid-base neutralization reaction, so that the purpose of neutralizing acid and base is achieved, and the small amount of carbon dioxide microbubbles are absorbed by water flow.

The invention solves the problem that gas and water with different pressures are mixed by the mixer, and the gas can be separated out from the liquid, and bubbles in the solution of the static mixer 13 are cut into micro bubbles which are more soluble in water than large bubbles, so as to generate carbonic acid solution. On the other hand, the pressure and time required for converting the gas-water mixture into saturated carbonic acid solution are required, the pipe distance between the diffuser 6 and the static mixer 13 is too long or too short, and the pipe diameter is too large or too small, which will cause problems of system pressure drop, carbon dioxide bubble precipitation or injection of the mixture into water without converting the mixture into carbonic acid solution, and the design of the annular coil 14 or the liquid storage tank 15 solves the problems, so that the carbonic acid solution is kept stable in the closed pressure environment.

Claims

1. The carbonic acid solution adding system is characterized by comprising a mixer and a diffuser; the device also comprises a carbon dioxide gas pipeline and a reaction water pipeline; a water pump is arranged on the reaction water pipeline; the outlet of the water pump is connected with the inlet of the mixer; the carbon dioxide gas pipeline is connected with the inlet of the mixer; an annular coil pipe and a long-distance pipeline or a liquid storage tank and a long-distance pipeline are arranged between the outlet of the mixer and the inlet of the diffuser; the diffuser is a hollow cylindrical object with one end open and the other end closed;

The diffuser is arranged in a raw water pipeline to be treated, which has water flowing, is positioned at the upstream of water flow, and a passage for releasing carbonic acid solution is formed on one half of the side wall of the diffuser; the diffuser is a hollow long cylindrical object with one closed end and one polygonal half of the cross section and the other circular arc, and a plurality of passages for releasing carbonic acid solution are formed on one half of the side wall of one polygonal side of the diffuser; the passage for releasing the carbonic acid solution is a combination of one or more rows of small holes and one or more rows of narrow gaps; the side of the diffuser with the combination of the small holes and the narrow gaps is opposite to the upstream of the water flow, so that the carbonic acid solution in the diffuser can be reversely sprayed out of the diffuser opposite to the water flow from the combination of the small holes and the narrow gaps, and the vortex enhanced mixing effect can be generated; the small holes or the narrow slits on each row are positioned on the same vertical line and are uniformly arranged; a plurality of channels for releasing carbonic acid solution on the same horizontal plane are uniformly arranged at a center included angle smaller than 180 degrees; two adjacent channels for releasing carbonic acid solution on the same horizontal plane are arranged at an acute central included angle; the channel for releasing carbonic acid solution can generate back pressure of more than 3bar and enable supersaturated carbonic acid solution to be sprayed into water to be treated at an outlet pressure of more than 3bar, so that a pressure difference of more than 2bar is ensured between the outlet pressure of the diffuser and the pressure of the water to be treated; the back pressure of the diffuser is more than 3bar, and the pressure of the whole system is maintained to be more than 3bar;

The state when the liquid passes through the narrow gap and the pressure is lower than 10bar is laminar flow, and the carbon dioxide is precipitated relatively little in the state;

mixing carbon dioxide gas with pressurized reaction water in a mixer to form a gas-water mixture with a certain pressure; the gas-water mixture is preliminarily formed into saturated carbonic acid solution in an annular coil pipe or a liquid storage tank; forming a supersaturated carbonic acid solution in the long-distance pipeline by the saturated carbonic acid solution; the length of the long-distance pipeline is within a reasonable range, and the residence time of the saturated carbonic acid solution in the long-distance pipeline is more than 5 seconds;

the mixer comprises a venturi tube and a static mixer; the venturi has a front constriction, a middle throat, and a rear expansion; the carbon dioxide gas filling port is positioned at the middle throat part of the venturi tube; the inlet of the static mixer is connected with the expansion section of the venturi tube; the static mixer outlet is connected with the diffuser inlet through an annular coil pipe and a long-distance pipeline, or is connected with the diffuser inlet through a liquid storage tank and a long-distance pipeline.

2. The carbonic acid solution feeding system according to claim 1, wherein the inlet of the reaction water pipe is connected with the water to be treated after the carbonic acid treatment is fed.

3. The carbonic acid solution feeding system according to claim 1 or 2, further comprising a liquid carbon dioxide storage tank, an electronic vaporizer or a fin heat exchanger, and a gas heater which are connected in sequence; or the carbonic acid solution adding system also comprises a Dewar tank or a steel cylinder and a gas heater which are connected in sequence; the outlet of the gas heater is connected with the inlet of the carbon dioxide gas pipeline.

4. The carbonic acid solution feeding system according to claim 1 or 2, wherein a water quality on-line detector is arranged at the downstream of the water flow in the raw water pipeline, and the water quality on-line detector is a pH probe or a water hardness on-line detector or a turbidity on-line detector; the water quality on-line detector is connected with the signal receiver, and the signal receiver is connected with the input end of the PLC controller; the output end of the PLC is connected with a carbon dioxide gas flow control valve; the water quality on-line detector transmits signals to the signal receiver in real time, and the opening of the carbon dioxide gas flow control valve can be controlled after the signals received by the signal receiver are processed by the PLC.