CN113772801A

CN113772801A - Carbonic acid solution dosing system

Info

Publication number: CN113772801A
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: 2021-12-10
Anticipated expiration: 2041-09-27
Also published as: CN113772801B

Abstract

The invention discloses a carbonic acid solution adding system. It 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 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 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 enables the supersaturated carbonic acid solution to be sprayed into the water to be treated at certain outlet pressure, and the pressure difference between the outlet pressure of the diffuser and the water pressure to be treated is ensured to be more than 2 bar. The carbonic acid solution feeding system can accurately adjust the water quality, can greatly reduce the generation of bubbles and greatly improve the utilization rate of carbon dioxide gas.

Description

Carbonic acid solution dosing 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 softening lime and the like.

Background

In surface water, reservoir water, wastewater and process water of manufacturing industry, pH is too high, which exceeds pH8.0 and even more than 9, and subsequent chemical treatment and product quality are seriously influenced by the too high and unstable pH of the water body. For example, the pH of the final effluent of the wastewater should be controlled to 6-9; in the process of coagulation and disinfection of a tap water plant, due to overhigh and unstable pH, chemical agents are excessively added, excessive chemical byproducts are generated, and the effluent water does not reach the relevant national standard; in the textile printing and dyeing industry, the pH of printing and dyeing process water is unstable, so that the color fastness of products is influenced, and the defective rate and the color fading of the products are caused; in natural water bodies such as rivers, lakes and the like, the pH is too high and changes in a waveform due to factors such as rich oxidation, algal explosion and the like of the water bodies; in water bodies such as fish ponds, shrimp ponds, swimming pools and the like, the pH is overhigh due to the addition of bactericides and disinfectants; the vegetable greenhouse and the flower planting need extra carbon dioxide gas to strengthen photosynthesis, and the carbon dioxide content can be increased by using the carbonated water for irrigation, thereby being beneficial to the growth of crops; .., water is not in place and is closely related to life and production of people, and the accurate control of the pH of water is an important part in the water treatment process flow.

The pH, also known as hydrogen ion concentration index, pH, is a measure of the activity of hydrogen ions in a solution, i.e., a measure of the acid-base degree of the solution in the general sense. Neutral aqueous solutions have a pH of 7 for acidic aqueous solutions, pH < 7, with higher pH values indicating greater alkalinity. The pH value is an important physicochemical parameter of water and sewage, and the pH value is one of important indexes for field control of water treatment. Adjusting and controlling the pH may facilitate chemical reactions and produce specific physicochemical changes.

In order to adjust the pH of water, acidifying agents such as sulfuric acid, hydrochloric acid, and the like are mainly used to neutralize the pH of water; the acidulant belongs to strong acid, which has various safety problems such as storage, transportation and corrosion, and importantly, the strong acid is used for neutralizing the pH value, so that the pH value of the strong acid is difficult to be accurately adjusted, and more importantly, the strong acid can destroy alkaline substances in water in the acid-base neutralization reaction process, and the alkaline substances are indispensable in drinking water.

At present, under the guidance of relevant national policies, many petrochemical plants all over the country are equipped with carbon dioxide purification equipment on a large scale 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 convenient for users to purchase locally. Due to the fact that cost and gas resources are easy to obtain, the operation cost of the carbonic acid adding system is almost equal to the use cost of the chemical agent, and through case implementation, a user only needs to invest initial equipment cost, and therefore the method is economical and feasible by utilizing the pH value of the carbonic acid neutralization water.

Carbonic acid is a weak acid, and when reacting with a basic substance, there is a buffer zone, so that the neutralization reaction with carbonic acid can accurately control or adjust the pH to a set value required by a customer. Moreover, most of carbon dioxide gas comes from petrochemical waste gas, and carbon dioxide is not released into the atmosphere again by utilizing the process that the pH of the carbonic acid solution neutralized water is consumed and completely reacts with carbon dioxide, so that the 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 indispensable important links, and how to adjust the pH of raw water has important significance in reducing the use of chemical agents and reducing byproducts.

In the seawater desalination process, the permeated water after seawater is subjected to multistage filtration is acidic and corrosive due to the removal of mineral substances, people need to add lime to remineralize the water, then need to add carbonic acid to react with calcium carbonate which is insoluble in water to generate water-soluble calcium bicarbonate, and the water added with the mineral substances can be drunk by people.

In the sewage treatment, because the hardness of the wastewater is higher, people need to add lime to carry out lime softening treatment on hard water, and then need to add carbonic acid to combine with calcium ions in the wastewater to generate calcium bicarbonate, so that the hardness of the wastewater is reduced; the lime softening treatment is to add hydrated lime Ca (OH)2 into water to react with alkaline components in the water to generate difficultly soluble CaCO3, the hydrated lime is a strong alkaline substance, the pH of the water after the hydrated lime is added can reach more than 10, high pH water needs acid neutralization, the pH can be accurately adjusted to a value desired by a customer by using carbonic acid, meanwhile, the carbonic acid reacts with the difficultly soluble CaCO3 generated in the reaction process of the hydrated lime and the water to generate water soluble calcium bicarbonate, H2CO3+ CaCO 3-Ca (HCO3)2 has no problems of pipeline blockage and the like caused by the generation of precipitates, and the lime softening treatment is an application by using the carbonic acid.

The prior art also uses carbon dioxide gas to neutralize the ph of water. Carbon dioxide gas can be dissolved in water to produce carbonic acid. Solubility, defined as the amount of a particular substance that can be dissolved in a particular solvent (resulting in a saturated carbonated solution). The solubility (solubility) of carbon dioxide in water at normal temperature and pressure is limited. The carbon dioxide gas requires a long time to react with water to form carbonic acid, a process known as recarbonation. Thus, the process by which carbon dioxide dissolves in water is a very slow chemical reaction process, and when carbon dioxide gas molecules enter water, they react with the water to form carbon dioxide (in an aqueous solution), carbonic acid, bicarbonate ions, and hydrogen ions, as shown in the following formula:

CO2+H2O->CO2+H2CO3+HCO3(-)+H(+)；

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

One way of neutralizing the pH value of water by using carbon dioxide gas is to directly feed the carbon dioxide gas to neutralize the pH value of the water, the feeding system needs a large-scale reaction tank with a stirrer, the carbon dioxide gas generates small bubbles through a diffuser, and the small bubbles of CO2 react with alkaline substances in the water for a long time and a long distance to achieve the purpose of reducing the pH value. However, small CO2 bubbles will escape from water during the whole reaction process, the effective utilization rate of carbon dioxide gas is only 30-60%, the low utilization rate of carbon dioxide gas means high use cost, and the pH can only be adjusted to 7, which cannot meet some process requirements.

Another way of neutralizing the ph of water using carbon dioxide gas is to mix the water to be treated with carbon dioxide gas through a venturi nozzle or a venturi static mixer and then feed the mixed solution into the water to be treated, which can be fed into shallow ponds and long distance pipelines, but also suffers from the problems of escape of small bubbles of CO2, low reaction efficiency and long reaction time.

The above two methods of adding carbon dioxide gas, both using the venturi principle, add carbon dioxide gas and mix it with the treated water to adjust the pH, and are therefore collectively referred to as gas addition systems. The gas adding systems have the defects of easy escape of CO2 small bubbles, low reaction efficiency, low utilization rate of carbon dioxide gas 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 which is used for adjusting the pH value, hardness or turbidity of water and can greatly improve the utilization rate of carbon dioxide gas.

The technical concept of the invention is as follows: mixing gaseous carbon dioxide with certain pressure and temperature and reaction water (low-pH effluent or low-hardness effluent or low-turbidity effluent treated by a process of adding carbonic acid) with certain pressure and 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 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 can be achieved (or the carbonic acid solution reacts with CaCO3 in the water, and the purpose of adjusting the hardness or turbidity of the water can be achieved), meanwhile, the generation of bubbles can be greatly reduced, and the utilization rate of the carbon dioxide gas can be greatly improved.

The purpose of the invention is realized by 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 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 open end and the other closed end; a passage for releasing carbonic acid solution is arranged on the cylindrical side wall of the diffuser; the channel 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 enables the supersaturated carbonic acid solution to be sprayed into the water to be treated at certain outlet pressure (can generate the back pressure of more than 3bar and enables the supersaturated carbonic acid solution to be sprayed into the water to be treated at the outlet pressure of more than 3bar), and the pressure difference of more than 2bar between the outlet pressure of the diffuser and the pressure of the water to be treated is ensured;

the diffuser is arranged in the raw water or water pipeline which flows by water and is to be treated, is positioned at the upstream of the water flow, and a passage for releasing carbonic acid solution is arranged on one half side wall of the diffuser; the channels for releasing carbonic acid solution are one or more, or one or more rows; the diffuser is inserted into the raw water or the water pipeline in a direction perpendicular to the water flow direction, one side of the diffuser, which is provided with a channel for releasing carbonic acid solution, is right opposite to the upstream of the water flow, so that the carbonic acid solution in the diffuser can be ejected out from the channel for releasing carbonic acid solution in a reverse direction opposite to the water flow, and the carbonic acid solution can be ejected out to be mixed and react with the water and simultaneously generate vortex to further enhance the mixing effect due to the low pressure of the other side;

alternatively, the diffuser is placed in a basin, pond or tank to be treated, where no water flows, and on both side walls or on the entire cylindrical side wall of the diffuser, there are opened a plurality of or a plurality of rows of channels for releasing carbonic acid solution (one or a plurality of circles of small holes and/or narrow slits can be made on the entire cylindrical side wall to realize 360 ° dispensing).

Furthermore, the inlet of the reaction water pipeline is connected with the water outlet of the water to be treated after being added with carbonic acid (namely, the water outlet treated by the carbonic acid adding system and the adding process is used as water for a water pump, namely reaction water), namely: the water outlet at the lower part of the water pipeline or the raw water flowing with water to be treated is connected with the inlet of the water pump through the reaction water pipeline; or the water outlet of the pool, the pond or the sewage tank to be treated, which has no water flow, is connected with the water pump inlet 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 connected in sequence; the outlet of the gas heater is connected with the inlet of the carbon dioxide gas pipeline.

The carbon dioxide gas which is gasified by the electronic vaporizer or the fin heat exchanger and is heated to a certain temperature and a certain pressure (the temperature is more than 30 ℃ and the pressure is more than 3bar) by the gas heater and the pressurized reaction water which is pressurized to a certain pressure (the pressure is more than 3bar) by the water pump form a gas-water mixture in the mixer; the gas-water mixture initially forms a saturated carbonic acid solution in the annular coil pipe or the liquid storage tank; saturated carbonic acid solution forms supersaturated carbonic acid solution in long-distance pipeline (straight pipe); the supersaturated carbonic acid solution is reversely sprayed into the raw water or water at the upstream of the water flow in the water pipeline or the water in the water inlet pool, the pond or the sewage tank through a channel for releasing the carbonic acid solution on the diffuser.

Furthermore, a water quality online detector (a pH probe or a water hardness online detector or a turbidity online detector and the like) is arranged at the downstream of the water flow in the raw water or water pipeline or at the water outlet of the pool, the pond or the sewage tank, and 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 a carbon dioxide gas flow control valve; the water quality on-line detector transmits signals to the signal receiver in real time, and the signals received by the signal receiver are processed by the PLC to control the opening size of the carbon dioxide gas flow control valve so as to control the adding amount of the carbon dioxide gas, thereby achieving the pH or hardness or turbidity which is desired to be controlled by a user.

Further, when the diffuser is arranged in raw water or a water pipeline which flows water to be treated, the diffuser is a hollow long cylindrical object with one half of a polygon and the other half of an arc-shaped cross section, and one end of the hollow long cylindrical object is closed, and a plurality of channels for releasing carbonic acid solution are formed in the side wall of one half of one side of the polygon of the diffuser; the channel for releasing the carbonic acid solution is one or more rows of small holes, one or more rows of narrow gaps, or a combination of one or more rows of small holes and one or more rows of narrow gaps (namely a combination of small holes and narrow gaps); or may be one or more apertures, one or more narrow slits, or a combination of one or more apertures and one or more narrow slits (i.e., a combination of both apertures and slits); the diffuser is inserted into the raw water perpendicularly to the water flow direction, and the side of the diffuser with the small holes and/or the narrow gaps is directly opposite to the upstream of the water flow, so that the carbonic acid solution in the diffuser can be reversely sprayed out from the small holes and/or the narrow gaps 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 does not flow water, the diffuser which realizes 360-degree throwing can be designed into a hollow cylinder shape, and can also be designed into a hollow square cylinder shape with a polygonal (such as square, hexagon and the like) section on the premise of ensuring back pressure.

Furthermore, the small holes and/or narrow slits in each row are located on the same vertical line and are uniformly arranged.

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

Further, the small holes are designed for small-diameter pipes below DN25, that is, when the long-distance pipe is a small-diameter pipe below DN25, the channel 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; or one or more apertures or a combination of one or more apertures and one or more narrow slits. Narrow gaps are more suitable for large-diameter pipes larger than DN25, that is, when the long-distance pipe is a large-diameter pipe larger than DN25, the passage for releasing carbonic acid solution is one or more rows of narrow gaps, or a combination of one or more rows of small holes and one or more rows of narrow gaps; 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 and a static mixer; the venturi has a front convergent section, an intermediate venturi section and a rear convergent section; the carbon dioxide gas filling port is positioned in the middle throat part of the Venturi tube (the carbon dioxide gas is injected into the reaction water in the direction vertical 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 by an annular coil or reservoir and long distance piping.

Further, the volume ratio of the carbon dioxide gas having a temperature of 30 ℃ or more and a pressure of 3bar or more 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 channel for releasing carbonic acid solution can generate back pressure of more than 3bar and make supersaturated carbonic acid solution be sprayed into water to be treated at outlet pressure of more than 3 bar; the diffuser backpressure was greater than 3bar and maintained the pressure throughout the system at greater than 3 bar. The pressure of the system is kept to be more than 3bar, so that the saturated carbonic acid solution can be further converted into the supersaturated carbonic acid solution, and otherwise, the utilization rate of the carbon dioxide is influenced by more than 97%. The concentration of the carbonic acid solution is more than 99% before the outlet of the diffuser, and when the carbonic acid solution passes through a small hole and a narrow gap, a small amount of carbon dioxide overflows from the solution in the form of bubbles due to pressure drop, so that the utilization rate of the whole carbon dioxide is more than 97%.

The solubility of carbon dioxide gas is temperature, pressure dependent: 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 lowering the water temperature and increasing the system pressure. The parameters of the water pump and the amount of carbon dioxide gas can be selected according to the conditions of each usage scenario, such as water temperature, water pressure, water quality parameters of raw water (water to be treated), stable pH value or hardness or turbidity desired by a user, and the position of a carbonation dispensing point.

By using an electronic vaporizer or a finned heat exchanger, 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 the gaseous carbon dioxide gasified by the electronic vaporizer or the fin heat exchanger is 0-10 ℃, the pressure can be adjusted to 5-10bar, the gaseous carbon dioxide is injected into the reaction water from a carbon dioxide gas filling port at the throat of the Venturi tube, at the moment, the water flow speed at the throat of the Venturi tube is high, the pressure is low, the carbon dioxide gas enters the Venturi tube in a pressure reduction process, dry ice can be generated in the pressure reduction process of the carbon dioxide gas, the dissolution and equipment efficiency of the carbon dioxide gas are influenced, therefore, a gas heater needs to be additionally arranged behind the electronic vaporizer or the fin heat exchanger, the temperature of the carbon dioxide gas is increased to more than 30 ℃ by a gas heater to prevent the generation of dry ice.

The formation of the saturated carbonic acid solution is started from the outlet of the static mixer (i.e. the saturated carbonic acid solution is formed in the annular coil or the liquid storage tank), and is a process that carbon dioxide bubbles gradually disappear and the saturated carbonic acid solution gradually forms.

The working principle of the carbonic acid solution adding system 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 converted into carbon dioxide gas continuously and quantitatively; alternatively, the carbon dioxide gas is stored in a dewar or a steel cylinder from which the carbon dioxide gas is released; carbon dioxide gas passes through a gas heater, and the temperature is kept above 30 ℃ and the pressure is kept above 3 bar; carbon dioxide gas with the temperature of more than 30 ℃ and the pressure of more than 3bar enters a mixer, meanwhile, reaction water (low pH effluent water or low hardness effluent water or low turbidity effluent water after the treatment of the adding carbonic acid process) enters the mixer after being pressurized to more than 3bar by a water pump, and the carbon dioxide gas and the pressurized reaction water are mixed in the mixer to form a gas-water mixture with certain pressure; the gas-water mixture forms a supersaturated carbonic acid solution through an annular coil or a liquid storage tank between the mixer and the diffuser and a long-distance pipeline and is conveyed to the diffuser, and the method specifically comprises the following steps: the gas-water mixture initially forms a saturated carbonic acid solution in the annular coil pipe or the liquid storage tank; saturated carbonic acid solution forms supersaturated carbonic acid solution in long-distance pipeline (straight pipe); the supersaturated carbonic acid solution is reversely sprayed into the water at the upstream of the raw water flow or the water in the water inlet tank through a channel (small hole and/or narrow gap) for releasing the carbonic acid solution on the diffuser; that is, the supersaturated carbonic acid solution forms a mixed solution of a high-concentration carbonic acid solution and a small amount of carbon dioxide microbubbles through small holes and/or narrow gaps in the diffuser, and the mixed solution is reversely sprayed into the water, so that 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 and reacts, and the small amount of carbon dioxide microbubbles are absorbed by the water flow, thereby achieving the purposes of neutralizing the 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 the water outlet of the water pool, the pond or the sewage tank and transmits signals to the signal receiver in real time, and the signals received by the signal receiver are processed by the PLC and then control the opening size of a carbon dioxide gas flow control valve to control the input amount of carbon dioxide gas so as to achieve the pH or hardness or turbidity which is desired to be controlled by a user.

The venturi static mixer combination kit (comprising venturi tube, static mixer, annular coil or liquid storage tank and long-distance pipeline) in the invention can be regarded as an integral structure, and mainly has the function of mixing carbon dioxide gas and reaction water with different pressures to generate supersaturated carbonic acid solution. Pressurized reaction water (low pH effluent and the like) firstly enters a contraction section of the Venturi, the pressure drop flow rate is increased when the pressurized reaction water passes through a throat part, the pressure of carbon dioxide is higher than that of the throat part, the carbon dioxide and the reaction water are mixed by pressure difference to form gas-water mixed liquid, the mixed liquid passes through an expansion section and then enters a static mixer, and the pressure of the mixed liquid at an outlet of the expansion section is smaller than the inlet pressure of the carbon dioxide and is larger than the inlet pressure of the reaction water. Thus, the mixed liquid can be smoothly transferred to the static mixer for mixing. The mixed solution is fully mixed by a static mixer. A long-distance pipeline and an annular coil or a liquid storage tank are arranged between the diffuser with the back pressure of more than 3bar and the static mixer, the mixture forms supersaturated carbonic acid solution in the annular coil or the liquid storage tank and the long-distance pipeline, and the supersaturated carbonic acid solution can reduce the generation of bubbles compared with the saturated carbonic acid solution.

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

The liquid carbon dioxide is gasified and warmed to prevent the generation of dry ice. In a high-temperature environment, the generation of dry ice can be prevented without these heating devices. The method of mixing air and water by using the Venturi is not limited to the Venturi form in the text.

The invention has the beneficial effects that:

the invention provides a complete liquid carbonic acid adding system, wherein gas carbon dioxide and reaction water are prepared into supersaturated carbonic acid solution in advance, and the supersaturated carbonic acid solution is added into the water through a diffuser, so that the pH value, the hardness or the turbidity of the water is adjusted.

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

1) firstly, the carbon dioxide gas with certain pressure and temperature and pressurized reaction water are mixed by a Venturi static mixer device, the gas and the water with different pressures form a gas-water mixture with consistent pressure by the Venturi static mixer, and the gas-water mixture is converted into saturated carbonic acid solution by an annular coil or a liquid storage tank; the saturated carbonic acid solution forms a supersaturated carbonic acid solution in a long-distance pipeline; the supersaturated carbonic acid solution is put into water through a diffuser; since the water pressure is at a low pressure, to avoid substantial escape of carbon dioxide bubbles in the mixed liquor during pressure drop, the present invention designs the diffuser, which functions to stabilize the system pressure, maintain the system back pressure and inject the carbonated solution into the water being treated. The supersaturated carbonic acid solution is sprayed out through the small holes of the diffuser and is subjected to acid-base neutralization reaction with alkaline substances in water instantly. Because of the pressure drop, a small amount of carbon dioxide bubbles escape from the carbonic acid solution, so the small amount of carbon dioxide bubbles and the high-concentration carbonic acid solution are ejected together to generate a strong vortex with water, the reaction speed is accelerated, and the reaction time is shortened. The application test case proves that the gas-water mixture or the mixed solution is converted into the supersaturated carbonic acid solution (the concentration of carbonic acid reaches more than 99 percent, and the effective utilization rate of the carbon dioxide gas reaches more than 97 percent), the reaction of the carbonic acid solution and water is liquid-liquid reaction, the neutralization reaction is completed within 20-30 seconds, the minimum pH can reach 5, and the pH fluctuation can be accurately and stably controlled. Compared with the carbon dioxide gas adding mode, the method has the advantages that an additional reaction tank is not needed, the utilization rate of the carbon dioxide gas is high, and the use cost of a user is greatly reduced.

2) In the prior art, a carbon dioxide gas feeding mode is used, a venturi nozzle or a venturi static mixer is a component for projecting gas into water, and the gas and the water are mixed at a contraction section or a throat 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 precipitated from the solution to form large bubbles, and only a small amount of carbon dioxide gas reacts with water to generate carbonic acid. Due to different pressures at different heights in the water, carbon dioxide bubbles escape from the water in open environments such as shallow pools, water pools and the like; carbon dioxide bubbles can collapse in the tubing, causing vibration and cavitation, and affecting the accuracy of the pH.

The main function of the diffuser in the present invention is to stabilize the pressure of the whole system above 3bar by means of the small holes and/or narrow slits shown in the figure, 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. A passage for releasing carbonic acid solution is arranged on one half side wall of the diffuser, and the passage for releasing the carbonic acid solution is a row or a plurality of rows of small holes, a row or a plurality of rows of narrow gaps, or a combination 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 central included angle of less than 180 degrees; two adjacent channels for releasing the carbonic acid solution on the same horizontal plane are arranged in an acute central included angle manner so as to ensure that the outlet pressure of the carbonic acid solution is more than 3bar and the carbonic acid solution is injected and mixed with water. The inlet pressure and outlet pressure (ideal) of the pressurized mixture are made to coincide through the small holes and/or narrow slits and are injected into the water at a very rapid rate. The pressure drop causes partial carbon dioxide gas to escape from the solution in the form of micro-bubbles, so that the mixed solution of carbonic acid solution and micro-bubbles is sprayed together to mix with water, meanwhile, because the small holes and/or narrow slits on each row are positioned on the same vertical line and are uniformly arranged, the pressure difference between the side with holes and the side without holes of the diffuser, and the pressure mixed solution forms vortex in the water, thereby further accelerating the acid-base neutralization reaction.

In the invention, the diffuser used for spraying the carbonic acid solution, the narrow gap and the small hole are used in combination or independently, and the small hole or the combination of the narrow gap and the small hole is designed for a small-diameter pipeline below DN 25; the narrow gap or the combination of the narrow gap and the small hole is more suitable for a large-caliber pipeline which is larger than DN 25; the solution ejected through the narrow gap has a larger contact surface with water than if only small holes were used; depending on the use scenario, a combination of small holes and/or narrow slits may also be used. The liquid flows through the small holes and is a contraction and re-diffusion process, the liquid state is turbulent flow, great pressure loss is generated, and more carbon dioxide gas is separated out due to too many small holes. The state when the liquid passes through a narrow gap and the pressure is below 10bar is laminar, in contrast to small pores, where the evolution of carbon dioxide is much less than small pores. However, in some cases, a combination of small holes and narrow slits is required, so that a small amount of carbon dioxide gas is lost, a certain turbulent flow is formed, and the mixing effect with raw water is enhanced. Compared with the small hole, the narrow gap can also solve the problem that the small hole deforms due to cavitation erosion and influences the ejection flow and pressure of the solution when the system is used.

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 the carbonic acid solution adding is wider, and the method can be applied to natural lakes, shallow channels, shallow pools, pipelines, liquid storage tanks and the like.

3) The invention solves the problem that gas is easy to separate out from liquid when gas and water with different pressures are mixed by the mixer, bubbles in the solution of the static mixer are cut into micro bubbles, and compared with large bubbles, the micro bubbles are more soluble in water to generate carbonic acid solution. On the other hand, the problems of system pressure drop, carbon dioxide bubble separation or injection of the mixture into water without conversion into the carbonic acid solution are caused by the excessive or too small pipe diameter of the pipeline, and the problems are solved by the design of the annular coil or the liquid storage tank, and the carbonic acid solution is kept stable in a closed pressure environment.

Drawings

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

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

FIG. 3 is a front view of the mixer 5+ reservoir 15 of the present invention;

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

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

FIG. 6 is a front view schematically showing the structure of the diffuser 6 according to the present invention;

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

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

Detailed Description

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

Example 1

As shown in fig. 1, the carbonic acid solution adding system for adjusting the pH value of water in the embodiment includes a liquid carbon dioxide storage tank 1, an electronic vaporizer 2, a gas heater 3, a mixer 5 and a diffuser 6 which are connected in sequence, and further includes a water pump 4 connected to an inlet of the mixer 5; between the mixer 5 and the diffuser 6 there is an annular coil 14 and a long-distance pipe 17 (straight pipe); the diffuser 6 is arranged in the water pipe through which the water to be treated flows, is positioned upstream of the water flow, and is inserted into the water pipe perpendicularly to the water flow direction; a plurality of channels for releasing carbonic acid solution are arranged on the half side wall of the diffuser 6, the channels 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 (reversely sprayed into the water at the upstream of water flow) at outlet pressure of more than 3bar, and 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 downstream water outlet of the water pipeline through which water flows to be treated is connected with the inlet of the water pump 4 through a reaction water pipeline 11 (the low-pH outlet water treated by the carbonic acid adding system and the adding process is used as the water used by the water pump 4, namely reaction water); carbon dioxide gas gasified by the electronic gasifier 2 and heated to a temperature of 30 ℃ or higher and a pressure of 3bar or higher by the gas heater 3 and pressurized reaction water pressurized to a pressure of 3bar or higher by the water pump form a gas-water mixture in the mixer 5; the gas-water mixture initially forms a saturated carbonic acid solution in the annular coil 14; the saturated carbonic acid solution forms a supersaturated carbonic acid solution in the long-distance pipeline 17 (straight pipe); the supersaturated carbonic acid solution is back-sprayed into the water in the water inlet conduit upstream of the water flow through the carbon acid solution releasing channels in the diffuser 6. A pH probe 7 is arranged at the downstream of water flow in the 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; the output end of the PLC is connected with a carbon dioxide gas flow instrument arranged at the outlet of the electronic vaporizer 2; the pH probe 7 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 to control the opening size of a switch of the carbon dioxide gas flow meter so as to control the adding amount of the carbon dioxide gas, thereby achieving the pH value which a user wants to control.

As shown in fig. 5-7, the diffuser 6 is a hollow long cylindrical object with one half of a polygon and the other half of an arc cross section and one closed end, and a plurality of channels for releasing carbonic acid solution are arranged on the half of the side wall of the polygon of the diffuser 6; the channel for releasing the carbonic acid solution is a combination of a small hole and a narrow gap, the middle of the channel is provided with a row of small holes 9, and the two sides of the channel are respectively provided with a row of narrow gaps 8; two adjacent channels (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 (namely, the central included angle formed by the connecting lines of the two adjacent channels for releasing carbonic acid solution and the central point is an acute angle, for example, two central included angles A, B in fig. 5 are acute angles), so as to ensure that the carbonic acid solution is ejected against the water flow direction to be mixed with the water to be treated at an outlet pressure of more than 3bar, and the outlet pressure can be used for mixing the carbonic acid solution with the water to be treated

As shown in fig. 1, 7, a diffuser 6 is provided in the water pipe through which water flows to be treated, upstream of the water flow; the diffuser 6 is inserted into the water pipeline in a direction perpendicular to the water flow, one side of the diffuser 6 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 sprayed out from the small holes 9 and the narrow gaps 8 in a reverse direction to the water flow, the carbonic acid solution is sprayed out to react with the water in a mixing way, and simultaneously, the vortex can be generated due to the low pressure of the other side to further enhance the mixing effect.

The small holes 9 and narrow slits 8 in the diffuser 6 enable a back pressure of above 3bar to be generated and the supersaturated carbonic acid solution to be injected into the water to be treated in the water conduit at an outlet pressure of greater than 3bar (back-injected into the water upstream of the water flow), ensuring a pressure differential of above 2bar 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 above 5 seconds, because the saturated carbonic acid solution needs to stay in the pipe for more than 5 seconds before the supersaturated carbonic acid solution can be formed. If the length of the long-distance pipe 17 is too short, the time for which the saturated carbonic acid solution stays 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 is formed. If the length of long distance pipe 17 is too long, there will be a pressure drop in the long pipe, the greater the pressure drop, the more small bubbles of CO2 will be generated and will come out of 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) includes a venturi tube and a static mixer 13; the venturi has a front convergent section 10, an intermediate venturi section and a rear convergent section 12; a carbon dioxide gas filling port 11 is positioned in the middle throat part of the Venturi tube (carbon dioxide gas is injected into low-pH water in a direction vertical 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 the static mixer 13 is connected to the inlet of the diffuser 6 by means of an annular coil 14 or a storage tank 15 and a long distance pipe 17.

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

The working principle of the carbonic acid solution adding system of the embodiment is as follows: the high-pressure low-temperature liquid carbon dioxide is stored in a liquid carbon dioxide storage tank 1; the liquid carbon dioxide comes out from the bottom of the liquid carbon dioxide storage tank 1 and is conveyed to the electronic vaporizer 2, and the liquid carbon dioxide is converted into carbon dioxide gas continuously and quantitatively; carbon dioxide gas passes through a gas heater 3, and the temperature is kept above 30 ℃ and the pressure is kept above 3 bar; carbon dioxide gas with the temperature of more than 30 ℃ and the pressure of more than 3bar enters a mixer 5, and meanwhile, reaction water (low-pH effluent water treated by a carbonic acid adding process) enters the mixer 5 after being pressurized to more than 3bar by a water pump 4; the volume ratio of carbon dioxide gas with a temperature above 30 ℃ and a pressure above 3bar to water with low pH is 1: 40; in the mixer 5, the carbon dioxide gas is mixed with the pressurized reaction water to form a gas-water mixture with a certain pressure; the gas-water mixture forms a 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 and is conveyed to the diffuser 6, the supersaturated carbonic acid solution forms a mixed solution of a high-concentration carbonic acid solution and a small amount of carbon dioxide micro-bubbles through small holes 9 and narrow gaps 8 on the diffuser 6 and is reversely sprayed into water, the carbonic acid solution meets alkaline substances in the water and starts to carry out acid-base neutralization reaction so as to achieve the purpose of neutralizing acid-base, and the small amount of carbon dioxide micro-bubbles are absorbed by water flow; the pH probe 7 is arranged at the downstream of water flow in a 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 to control the opening size of a carbon dioxide gas flow control valve so as to control the adding amount of carbon dioxide gas and achieve the pH value which a user wants to control.

Firstly, mixing carbon dioxide gas with certain pressure and heating with pressurized reaction water through a Venturi tube, and then forming a gas-water mixture with pressure through a static mixer, wherein the gas-water mixture is converted into a 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 pipeline 17; the supersaturated carbonic acid solution is dosed into the water through the diffuser 6 (shown in fig. 5-7); since the pressure of the water is at a low pressure, in order to avoid a large escape of carbon dioxide bubbles in the mixed liquor during the pressure drop, the invention envisages this diffuser 6 (shown in figures 5-7), the function of this diffuser 6 being to stabilize the pressure of the system, maintain the back pressure of the system and inject the carbonated solution into the water being treated. The supersaturated carbonic acid solution is sprayed through the small holes 9 and the narrow slits 8 on the diffuser 6, and is subjected to acid-base neutralization reaction with the alkaline substance in the water instantly. Because of the pressure drop, a small amount of carbon dioxide bubbles escape from the carbonic acid solution, so 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 accelerated, and the reaction time is shortened. Application test cases prove that the gas-water mixture or the mixed solution is converted into a supersaturated carbonic acid solution (the concentration of carbonic acid reaches more than 99 percent, and the effective utilization rate of carbon dioxide gas reaches more than 97 percent), the acid-base neutralization reaction of the carbonic acid solution and alkaline substances in water is liquid-liquid reaction, the neutralization reaction is completed within 20-30 seconds, the minimum pH can reach 5, and the pH fluctuation can be accurately and stably controlled. Compared with a carbon dioxide gas adding mode, the method has the advantages that an additional reaction tank is not needed, the utilization rate of the carbon dioxide gas is high, and the use cost of a user is greatly reduced.

As shown in fig. 2 and 3, carbon dioxide gas at a certain pressure and at a certain temperature is injected into reaction water at a lower pressure than the carbon dioxide gas by a venturi tube (the reaction water may be low-pH factory water which is treated by a process of adding carbonic acid and then subjected to coagulating sedimentation and filtering to remove impurities, so as to prevent impurities from mixing into the static mixer 13 and generate unnecessary cleaning and maintenance), and the gas-water mixture passes through the static mixer 13 to achieve the purpose of better dispersion and mixing of carbon dioxide bubbles. Further, the static mixer 13 is connected with the diffuser 6 through the annular coil 14 or the liquid storage tank 15 and the long-distance pipeline (straight pipe) 17, the backpressure of a system is kept to be more than 3bar by the small holes and/or the narrow gaps on the diffuser 6, so that the gas-water mixture is converted into the carbonic acid solution and kept in a supersaturated state, the supersaturated carbonic acid solution is sprayed into the water to be treated through the small holes and/or the narrow gaps on the diffuser 6, carbon dioxide bubbles are absorbed by water vortex, and meanwhile, the carbonic acid solution can quickly react with alkaline substances in the water, and 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 higher than that of the inner side wall 20, carbon dioxide bubbles are gradually dissolved into water under the action of continuous pressure difference, a saturated carbonic acid solution is formed, a supersaturated carbonic acid solution is further formed, the supersaturated carbonic acid solution is sent to the diffuser 6 through the long-distance pipeline 17, meanwhile, the back pressure of the diffuser 6 maintains the whole conversion process and the pipeline pressure, the carbon dioxide bubbles can be prevented from escaping from the carbonic acid solution due to pressure drop, and the carbonic acid solution is prevented from returning to the gas-water mixture state.

The gas-water mixed supersaturated carbonic acid solution forming device (comprising the Venturi tube, the static mixer 13, the annular coil 14 and the long-distance pipeline 17) can be regarded as an integral structure, and mainly has the function of mixing carbon dioxide gas with different pressures and water with low pH value to form the supersaturated carbonic acid solution. As shown in fig. 2 and 3, when the pressurized low-pH water first enters the constriction section 10 of the venturi and passes through the throat part, the pressure drop flow rate increases, the pressure of the carbon dioxide gas is higher than that at the throat part, the carbon dioxide gas and the low-pH water are mixed by the pressure difference to form gas-water mixed liquid, the mixed liquid passes through the expansion section 12 and then enters the static mixer 13, and the pressure of the mixed liquid 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 mixed liquid to be smoothly fed to and mixed in the static mixer 13. The mixed solution is thoroughly mixed by a static mixer 13. Between the diffuser 6, which has a pressure above 3bar as back pressure, 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 and 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 body with one closed end, and is inserted in a direction perpendicular to the water flow, the side of the diffuser 6 with the small holes 9 and/or the narrow slits 8 faces the upstream of the water flow (see fig. 7), the top end of the diffuser 6 is open (the unclosed end) and can allow the supersaturated carbonic acid solution to enter, and the supersaturated carbonic acid solution is sprayed from the small holes 9 and/or the narrow slits 8 in a reverse direction to the water flow and then mixed with the water. The process of the solution entering the water is a depressurization process, in the process of pressure balance, 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 spraying through the small holes 9 and/or the narrow gaps 8, the small bubbles are absorbed by the water flow, the carbonic acid solution reacts with the water, and the whole process is a process of intensified mixing and rapid neutralization reaction.

The function of the diffuser 6: in addition to injecting the carbonic acid solution into the water, while maintaining the pressure of the entire system, carbon dioxide gas is prevented from escaping from the carbonic acid solution. The small holes 9 and the narrow gaps 8 on the diffuser 6 keep the system back pressure more than 3bar, the supersaturated carbonic acid solution is reversely sprayed into the water to be treated through the small holes 9 and the narrow gaps 8 on the diffuser 6, and the carbonic acid solution can quickly 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 line pressure, preventing carbon dioxide bubbles from escaping from the carbonated solution due to pressure drop, preventing the carbonated solution from returning to the gas-water mixture state.

In summary, the present invention provides a complete carbonic acid solution adding system, wherein gaseous carbon dioxide and low pH water are pre-mixed to form a supersaturated carbonic acid solution, and the supersaturated carbonic acid solution is added into water through a diffuser to adjust the pH of the water.

In the prior art, a carbon dioxide gas feeding mode is used, a venturi nozzle is a component for projecting gas into water, and the gas and the water are mixed at a contraction section or a throat 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 precipitated from the solution to form large bubbles, and only a small amount of carbon dioxide gas reacts with water to generate carbonic acid. Due to different pressures at different heights in the water, carbon dioxide bubbles escape from the water in open environments such as shallow pools, water pools and the like; carbon dioxide bubbles in the pipeline can be broken or directly enter raw water, only a small part of carbon dioxide participates in the neutralization reaction, the accuracy of pH control is influenced, and meanwhile vibration and cavitation of the pipeline are caused.

The main function of the diffuser 6 in the present invention is to utilize the small holes 9 and narrow slits 8 shown in fig. 5-7 to stabilize the pressure of the whole system above 3bar, 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 a row of small holes 9 and a plurality of rows of narrow slits 8 (a combination of small holes and narrow slits); a plurality of channels for releasing carbonic acid solution on the same horizontal plane are uniformly arranged at a central included angle of less than 180 degrees; two adjacent channels for releasing carbonic acid solution on the same horizontal plane are arranged in an acute central included angle to ensure that the outlet pressure of the carbonic acid solution is more than 3bar to jet out and mix with water. The inlet pressure and the outlet pressure (ideal state) of the pressure mixed liquid are consistent through the small hole 9 and the narrow slit 8, and are injected into the water at a very fast speed. Because the pressure drops, the pressure difference can cause part of the carbon dioxide gas to escape from the solution in the form of micro bubbles, therefore, the mixed solution of the carbonic acid solution and the micro bubbles is sprayed together to be mixed with the water, meanwhile, because the small holes 9 or the narrow slits 8 on each row are positioned on the same vertical line and are uniformly arranged, the pressure difference exists between the porous side and the non-porous side of the diffuser 6, the pressure mixed solution forms vortex in the water, and 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 method can be applied to natural lakes, shallow channels, shallow pools, pipelines, liquid storage tanks and the like.

Example 2

As shown in fig. 2, the method for adding carbonic acid by using the small-sized carbonic acid solution adding system in the embodiment is basically the same as the method for adding carbonic acid by using the small-sized carbonic acid solution adding system in the embodiment 1; the difference lies in that: the diffuser 6 is arranged in a pool to be treated without flowing water, and a plurality of channels for releasing carbonic acid solution are arranged on the side walls of two sides of the diffuser 6; the passage for releasing carbonic acid solution is a combination of small hole and narrow gap.

As shown in fig. 2, the diffuser 6 is arranged in a pool to be treated, which has no water flow, and a plurality of circles of small holes and narrow gaps (a row of small holes 9 and a row of narrow gaps 8 are staggered) are arranged 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 the carbonic acid solution 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 tank at an outlet pressure of more than 3bar, and 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 pool to be treated, which has no water flow, is connected with the inlet of the water pump 4 through a reaction water pipeline 11 (the low-pH outlet water treated by the carbonic acid adding system and the adding process of the invention is used as the water used by the water pump 4, namely the reaction water).

The working principle of the carbonic acid solution adding system of the embodiment is as follows: carbon dioxide gas gasified by the electronic vaporizer 2 and heated to have a temperature of 30 ℃ or higher and a pressure of 3bar or higher by the gas heater 3 and 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 gas-water mixture initially forms a saturated carbonic acid solution in the annular coil 14; the saturated carbonic acid solution forms a supersaturated carbonic acid solution in the long-distance pipeline 17 (straight pipe); the supersaturated carbonic acid solution is sprayed into the water of the intake pool 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 a water outlet of the water pool, 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 a signal 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 size of the control valve 14 so as to control the adding amount of the carbonic acid solution, thereby achieving the pH value which a user wants to control.

Example 3

The carbonic acid solution adding system in the embodiment is basically the same as the carbonic acid solution adding system in the embodiment 1; the difference lies in that: between the mixer 5 and the diffuser 6, a reservoir 15 and a long-distance pipe 17 (straight pipe) are provided. The long-distance pipeline 17 is a large-diameter pipeline larger than DN25, the channel for releasing the carbonic acid solution is a narrow gap 8, the middle part is provided with a row of narrow gaps 8, and two sides are respectively provided with a row of narrow gaps 8.

The pressure gas-water mixture enters the liquid storage tank 15, 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, and finally the supersaturated carbonic acid solution is formed. The supersaturated carbonic acid solution is fed to the diffuser 6 through a long distance pipe 17 (straight pipe), and at the same time, the back pressure of the diffuser 6 will maintain the whole conversion process and the pipe pressure, preventing carbon dioxide bubbles from escaping from the carbonic acid solution due to pressure drop, and preventing the carbonic acid solution from returning to the gas-water mixture state.

The working principle of the carbonic acid solution adding system of the embodiment is as follows: the high-pressure low-temperature liquid carbon dioxide is stored in a liquid carbon dioxide storage tank 1; the liquid carbon dioxide comes out from the bottom of the liquid carbon dioxide storage tank 1 and is conveyed to the electronic vaporizer 2, and the liquid carbon dioxide is converted into carbon dioxide gas continuously and quantitatively; carbon dioxide gas passes through a gas heater 3, and the temperature is kept above 30 ℃ and the pressure is kept above 3 bar; carbon dioxide gas with the temperature of more than 30 ℃ and the pressure of more than 3bar enters a mixer 5, meanwhile, water (low pH effluent water treated by a carbonic acid adding process) is pressurized to more than 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 and is conveyed to the diffuser 6, the supersaturated carbonic acid solution forms mixed solution of high-concentration carbonic acid solution and a small amount of carbon dioxide micro-bubbles 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 carry out acid-base neutralization reaction so as to achieve the purpose of neutralizing acid-base, and the small amount of carbon dioxide micro-bubbles are absorbed by water flow; the pH probe 7 is arranged at the downstream of the water flow and 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 a carbon dioxide gas flow meter to control the dosage of the carbon dioxide gas so as to achieve the pH value which is desired to be controlled by a user.

Firstly, mixing carbon dioxide gas with certain pressure and heating with pressurized reaction water through a Venturi tube, and then forming a gas-water mixture with pressure through a static mixer, wherein the gas-water mixture is converted into a saturated carbonic acid solution through a liquid storage tank 15; the saturated carbonic acid solution forms a supersaturated carbonic acid solution in a long-distance pipeline; the supersaturated carbonic acid solution is dosed into the water through the diffuser 6 (shown in fig. 5-7); since the water pressure is at a low pressure, to avoid substantial escape of carbon dioxide bubbles in the mixed liquor during pressure drop, the present invention designs this diffuser 6 (shown in fig. 5-7), the function of this diffuser 6 being to stabilize the system pressure, maintain the system back pressure and inject the carbonic acid solution into the water being treated. The supersaturated carbonic acid solution is sprayed through the small holes of the diffuser 6 and is instantly subjected to acid-base neutralization reaction with the alkaline substance in the water. Because of the pressure drop, a small amount of carbon dioxide bubbles escape from the carbonic acid solution, so the small amount of carbon dioxide bubbles and the carbonic acid solution are jetted together to generate strong vortex with water, thereby accelerating the reaction speed and shortening the reaction time. Application test cases prove that the gas-water mixture or the mixed solution is converted into a supersaturated carbonic acid solution (the concentration of carbonic acid reaches more than 99 percent, and the effective utilization rate of carbon dioxide gas reaches more than 97 percent), the acid-base neutralization reaction of the carbonic acid solution and alkaline substances in water is liquid-liquid reaction, the neutralization reaction is completed within 20-30 seconds, the minimum pH can reach 5, and the pH fluctuation can be accurately and stably controlled. Compared with the carbon dioxide gas adding mode, the method has the advantages that an additional reaction tank is not needed, the utilization rate of the carbon dioxide gas is high, and the use cost of a user is greatly reduced.

As shown in fig. 2 and 3, carbon dioxide gas at a certain pressure and at a certain temperature is injected into reaction water at a lower pressure than the carbon dioxide gas by a venturi tube (the reaction water may be low-pH factory water which is treated by a process of adding carbonic acid and then subjected to coagulating sedimentation and filtering to remove impurities, so as to prevent impurities from mixing into the static mixer 13 and generate unnecessary cleaning and maintenance), and the gas-water mixture passes through the static mixer 13 to achieve the purpose of better dispersion and mixing of carbon dioxide bubbles. Further, the static mixer 13 is connected with the diffuser 6 through the liquid storage tank 15 and a long-distance pipeline (straight pipe), the backpressure of a system is kept to be more than 3bar by the small holes and/or the narrow gaps on the diffuser 6, so that a 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 the narrow gaps on the diffuser 6, carbon dioxide bubbles are absorbed by a water vortex, and meanwhile, the carbonic acid solution can quickly react with alkaline substances in the water, and the purpose of neutralizing the pH value is achieved.

The gas-water mixed supersaturated carbonic acid solution forming device (comprising the Venturi tube, the static mixer 13, the liquid storage tank 15 and the long-distance pipeline 17) can be regarded as an integral structure, and mainly has the function of mixing 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 section 10 and passes through the throat, the pressure drop flow rate increases, the pressure of the carbon dioxide gas is higher than that of the throat, the carbon dioxide gas and the low pH water are mixed by the pressure difference to form a gas-water mixed liquid, the mixed liquid passes through the expansion section 12 and then enters the static mixer 13, and the pressure of the mixed liquid 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 mixed liquid to be smoothly fed to the static mixer 13 and mixed. The mixed solution is thoroughly mixed by a 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, the mixture forms over-saturated carbonic acid solution in the long-distance pipeline 17, and compared with the saturated carbonic acid solution, the supersaturated carbonic acid solution can reduce the generation of air bubbles.

Example 4

The carbonic acid solution adding system in the embodiment is basically the same as the carbonic acid solution adding system in the embodiment 1; the difference lies in that: the electronic vaporizer 2 is replaced by a fin heat exchanger, and carbon dioxide gas is heated to have a temperature of more than 20 ℃ by the fin heat exchanger; the long-distance pipeline 17 is a small-diameter pipeline of DN25, the channel for releasing the carbonic acid solution is a combination of small holes and narrow slits, the middle of the long-distance pipeline is provided with a row of narrow slits 8, and two sides of the long-distance pipeline are respectively provided with a row of small holes 9.

Example 5

The carbonic acid solution adding system in the embodiment is basically the same as the carbonic acid solution adding system in the embodiment 1; the difference lies in that: the liquid carbon dioxide storage tank 1 and the electronic vaporizer 2 are not arranged, and are replaced by a dewar tank or a steel cylinder. Carbon dioxide gas is discharged from a Dewar flask or a steel cylinder, heated to a temperature above 30 ℃ and a pressure above 3bar by a gas heater 3, and pressurized reaction water pressurized to a pressure above 3bar by a water pump 4 in a mixer 5 to form a gas-water mixture; the gas-water mixture initially forms a saturated carbonic acid solution in the annular coil 14; saturated carbonic acid solution forms supersaturated carbonic acid solution in long-distance pipeline 17 and is transported to diffuser 6, supersaturated carbonic acid solution forms mixed solution of high concentration carbonic acid solution and a small amount of carbon dioxide microbubbles through small holes and/or narrow gaps in diffuser 6 and is reversely sprayed into water, carbonic acid solution meets alkaline substances in water and starts to carry out acid-base neutralization reaction so as to achieve the purpose of neutralizing acid-base, and a small amount of carbon dioxide microbubbles are absorbed by water flow.

The invention solves the problem that gas can be separated out from liquid when gas and water with different pressures are mixed by the mixer, bubbles in the solution of the static mixer 13 are cut into micro bubbles, and compared with large bubbles, the micro bubbles are more soluble in water to generate carbonic acid solution. On the other hand, the pressure and time required for the conversion of the gas-water mixture into the saturated carbonic acid solution, the too long or too short distance of the pipeline between the diffuser 6 and the static mixer 13, and the too large or too small pipe diameter of the pipeline all cause the problems of system pressure drop, carbon dioxide bubble precipitation or the injection of the mixture into water without being converted into the 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. A carbonic acid solution feeding 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 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 arranged in the water to be treated; the diffuser is a hollow cylindrical object with one open end and the other closed end; a passage for releasing carbonic acid solution is arranged on the cylindrical side wall of the diffuser; the channel 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 enables the supersaturated carbonic acid solution to be sprayed into the water to be treated at certain outlet pressure, so that the 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 the raw water or water pipeline which flows by water and is to be treated, is positioned at the upstream of the water flow, and a passage for releasing carbonic acid solution is arranged on one half side wall of the diffuser; the channels for releasing carbonic acid solution are one or more, or one or more rows; the diffuser is inserted into the raw water or the water pipeline in a direction perpendicular to the water flow direction, one side of the diffuser, which is provided with a passage for releasing the carbonic acid solution, is right opposite to the upstream of the water flow, so that the carbonic acid solution in the diffuser can be reversely sprayed out from the passage for releasing the carbonic acid solution opposite to the water flow and a vortex reinforced mixing effect can be generated;

alternatively, the diffuser is placed in a basin, pond or tank to be treated, where no water flows, and on both side walls or on the entire cylindrical side wall of the diffuser, there are opened a plurality or more rows of channels for releasing the carbonic acid solution.

2. The carbonation solution dosing system according to claim 1, wherein said channel for releasing carbonation solution is capable of generating a back pressure of above 3bar and injecting supersaturated carbonation solution into water to be treated at an outlet pressure of greater than 3 bar; the diffuser backpressure was greater than 3bar and maintained the pressure of the entire system at greater than 3 bar.

3. The carbonic acid solution dosing system as set forth in claim 1 or 2, wherein the reaction water pipe inlet is connected to the outlet of the water to be treated after the carbonic acid treatment is dosed.

4. The carbonic acid solution dosing system of claim 1 or 2, further comprising a liquid carbon dioxide storage tank, an electronic vaporizer or a finned heat exchanger, and a gas heater, which are connected in sequence; or the carbonic acid solution adding system also comprises a Dewar flask 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.

5. The carbonic acid solution dosing system as claimed in claim 1 or 2, wherein a water quality 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, the pond or the sewage tank, 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; the output end of the PLC is connected with a carbon dioxide gas flow control valve; the signal receiver is transmitted to the signal in real time through the water quality on-line detector, and the signal received by the signal receiver can control the opening size of the carbon dioxide gas flow control valve after being processed by the PLC.

6. The carbonation solution dosing system according to claim 1 or 2, wherein the diffuser is a hollow long cylindrical object with one end closed and one half of the cross section of the hollow long cylindrical object being a polygon and the other half being an arc, and a plurality of channels for releasing the carbonation solution are formed on the side wall of one half of one side of the polygon of the diffuser; the channel for releasing the carbonic acid solution is one or more rows of small holes, one or more rows of narrow gaps, or a combination of one or more rows of small holes and one or more rows of narrow gaps; or one or more apertures, one or more narrow slits, or a combination of one or more apertures and one or more narrow slits; the diffuser is inserted into the raw water perpendicularly to the water flow direction, and the side of the diffuser with the small holes and/or the narrow gaps is 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 the narrow gaps in a reverse direction to the water flow.

7. The carbonation dosing system according to claim 6, wherein the orifices and/or slots in each row are positioned in a vertical line and are evenly spaced.

8. The carbonic acid solution dosing system as claimed in claim 1 or 2, wherein a plurality of the channels for releasing the carbonic acid solution on the same horizontal plane are uniformly arranged with a central included angle of less than 180 °; two adjacent channels for releasing carbonic acid solution on the same horizontal plane are arranged at an acute central included angle.

9. The carbonation solution dosing system according to claim 1 or 2, wherein when said long distance pipe is a small diameter pipe below DN25, said carbonation solution releasing passage 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; or one or more apertures, or a combination of one or more apertures and one or more narrow slits; when the long-distance pipeline is a large-diameter pipeline which is larger than DN25, the channel for releasing the carbonic acid solution is one or more rows of narrow gaps, or a combination of one or more rows of small holes and one or more rows of narrow gaps; or one or more narrow slits, or a combination of one or more apertures and one or more narrow slits.

10. The carbonic acid solution dosing system as claimed in claim 1 or 2, wherein the mixer comprises a venturi tube and a static mixer; the venturi tube has a front convergent section, a middle venturi section and a rear convergent section; the carbon dioxide gas filling port is positioned in 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 to the diffuser inlet by an annular coil or reservoir and long distance piping.