KR102335823B1 - manufacturing method for urea solution - Google Patents

Abstract

Disclosed is a method for producing a urea solution capable of minimizing an impurity content of the urea solution by using a low-temperature aging process when producing the urea solution. Provided is a device for producing a urea solution which comprises: (a) a stirrer; (b) a storage tank for storing a urea solution produced in the stirrer for a certain period of time; and (c) a solid-liquid separation means for purifying the urea solution stored in the storage tank for a certain period of time.

Description

Urea water manufacturing method {manufacturing method for urea solution}

The present invention relates to a method for producing urea water, and more particularly, to a method for producing urea water capable of minimizing the impurity content of urea water by using a low-temperature aging process when producing urea water.

Recently, as the problem of environmental pollution has emerged as a major issue, even in the case of automobiles, electric vehicles, hydrogen vehicles, solar vehicles, and hybrid vehicles that do not use or use fossil fuels are being actively developed and commercialized.

However, despite the emergence of these eco-friendly vehicles, vehicles using gasoline or diesel as fuel still dominate the automobile market, and it is expected that this will be maintained for a considerable period of time.

In the case of gasoline or diesel internal combustion engine vehicles using such fossil fuels, the problem of environmental pollution due to exhaust gas is serious. Among them, in the case of diesel vehicles, emissions of soot, nitrogen oxides (NOx) and fine dust are recognized as serious problems. is strictly regulated.

Therefore, the exhaust system of diesel vehicles uses DOC (Diesel Oxidation Catalyst), DPF to reduce pollutants such as carbon monoxide (CO), hydrocarbons (HC), particulate matter, and nitrogen oxides (NOx) contained in exhaust gas. (Diesel Particulate matter Filter), SCR (Selective Catalyst Reduction) and LNT (Lean NOx Trap) are provided with an exhaust gas post-treatment device.

Among them, the exhaust gas post-treatment device to which SCR is applied (hereinafter referred to as the 'SCR device') functions to reduce nitrogen oxides in the exhaust gas to nitrogen and oxygen by injecting a reducing agent such as urea water into the exhaust pipe.

That is, in the SCR device, when a reducing agent is injected into the exhaust pipe, the reducing agent is converted to ammonia (NH3) by the heat of the exhaust gas, and nitrogen oxide is produced as a catalytic reaction of nitrogen oxide and ammonia in the exhaust gas by the SCR catalyst. It can be reduced with nitrogen gas (N2) and water (H2O)

At this time, the urea water used in the SCR device is a chemical substance made by mixing pure water and urea, a raw material of urea fertilizer, and must pass the inspection according to Article 74 (2) of the Air Conservation Act to be commercially available in Korea. Urea is a polar material that dissolves easily when heat is applied, but has the disadvantage that impurities such as burette and triuret are also dissolved together. The urea water in which the burette, triuret, etc. is dissolved causes corrosion and clogging in the SCR device. In order to precipitate and purify these impurities, a process of removing them using a filter after dissolving at a low temperature is necessary even if it takes some time.

The existing method for producing urea water is manufactured by stirring urea (raw material) and pure water (water), and then purifying it to remove impurities. At this time, in the process of stirring urea and water, a motor is installed on the upper part, and the impeller installed in the motor is rotated to stir, but there is a problem that the stirring efficiency is reduced in a low temperature state due to the endothermic action when stirring the urea and pure water. In addition, since urea water is produced using heated water due to the nature of the endothermic reaction, when impurities are dissolved in the urea water and added to the SCR device, it has the disadvantage of reducing the lifespan of the SCR device.

In order to improve this, impurities are removed using the filter in the urea water prepared as described above, but the filter life is shortened due to filter clogging caused by impurities, and high-purity urea water for use in the SCR device is manufactured In this case, since a large amount of filters are used, the manufacturing cost thereof is increased, and in the case of impurities dissolved in high temperature water, it is difficult to remove only by using a filter.

Therefore, there is a need for a method for producing urea water in which the generation of such impurities can be minimized.

(0001) Republic of Korea Patent Registration No. 10-1640401 (0002) Republic of Korea Patent Registration No. 10-1703959

The present invention has been devised to solve the above problems, and an object of the present invention is to provide a method for producing urea water capable of minimizing the content of impurities in urea water by producing urea water at a low temperature.

Another object of the present invention is to provide a method for producing urea water capable of increasing the lifespan of an SCR device by filtering the urea water produced through a low-temperature process to remove unreacted urea and solid impurities.

Another object of the present invention is to provide a urea water manufacturing method capable of precipitating and separating impurities in the urea water by aging the produced urea water at a low temperature, thereby maximizing the life of the filter.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

The present invention in order to solve the above problems (a) a stirrer; (b) a storage tank for storing the urea water produced in the agitator for a certain period of time; And (c) provides a urea water production apparatus comprising a solid-liquid separation means for purifying the urea water stored for a certain period in the storage tank.

In one embodiment, the stirrer, a cylindrical body; a rotating shaft installed through the lower end of the stirring body to rotate the stirring screw installed in the lower part of the cylindrical body; a screw for stirring connected to one end of the rotating shaft and installed in the lower part of the body; a rotating motor installed at the lower end of the rotating shaft and rotating the rotating shaft and the agitating screw; a water supply part formed on the upper part of the cylindrical body; a urea supply unit installed on the side of the water supply unit; and a urea water outlet installed under the cylindrical body, wherein the stirring screw forms an upward flow from the center of the cylindrical body, and crushes ice generated when the water and the urea react, Urea is supplied to the stirrer at a rate of 0.1 to 0.5 kg/min per 100 kg of water, 30 to 35 parts by weight of the urea is supplied relative to 100 parts by weight of water, and a temperature control means is included in the cylindrical body; The temperature control means may include: a temperature control pipe spirally formed inside the cylindrical body, one end connected to a lower portion of the cylindrical body, and a lower end connected to the upper portion of the cylindrical body; a heat supply unit for supplying heat having a constant temperature to the temperature control pipe; and a temperature control unit for heating or cooling the fruit; the temperature control pipe is formed in a spiral shape having a diameter of 1/4 to 3/4 of the diameter of the cylindrical body; The cylindrical body can maintain a temperature of -15 to 5° C. by the temperature control means, and the storage tank includes: a cylindrical storage tank body; a urea water discharge unit formed at a lower portion of the storage tank body; a funnel-shaped impurity collecting unit connected to the lower end of the storage tank body; and a warming means surrounding the storage tank body and the outer circumferential surface of the impurity collecting part; a temperature maintaining means capable of maintaining the storage tank at a constant temperature is included in the heat retention means; The solid-liquid separation means, centrifugal separation means for primary separation of the urea water supplied from the storage tank; and a separation filter for secondary separation of the urea water that has passed through the separation filter, wherein the centrifugal separation means supplies the urea water discharged from the storage tank in a tangential direction, and a solid material having a specific gravity and a low specific gravity 1 a first cyclone separator for separating the tea-treated urea water by centrifugal force; and 2 to 20 pieces are arranged at equal intervals along the upper outer peripheral surface of the first cyclone separator, the number of primary treatment elements discharged from the first cyclone separator is supplied in a tangential direction, and the solid material with a large specific gravity and secondary treatment with a low specific gravity a plurality of second cyclone separators for separating urea water by centrifugal force, the lower outlet of the second cyclone separator is tangentially connected to the upper part of the first cyclone separator, and the solid material separated in the second cyclone separator is supplied to the upper portion of the first cyclone separator and mixed with urea water in the first cyclone separator to be separated, and the separation filter includes; Cylindrical separation filter body; a porous filter installed at the middle of the main body to spatially separate the upper part and the lower part of the main body; a urea water supply unit installed at a lower portion of the main body of the separation filter; a funnel-shaped waste collection unit connected to the lower end of the separation filter body; and a urea water discharge part installed on the upper part of the separation filter body; A backwash urea water supply unit for backwashing the separation filter by supplying urea water from a storage tank is installed on the upper portion of the separation filter body, and the porous filter includes: a connection part connected to the middle portion of the separation filter body; 2 to 20 protrusions formed in the center of the connection part; and a vibration generating part connected to one side of the connection part and vibrating the porous filter when supplying the urea water for backwashing, through the impurity collecting part of the storage tank, the impurity discharge part of the separation filter, and the first cyclone separator The discharged impurities are discharged through the impurity separator, the impurity separator, the upper dewatering belt; lower dewatering belt; and a roller for pressing the upper dewatering belt and the lower dewatering belt; The upper dewatering belt and the lower dewatering belt are belts manufactured by bonding a hygroscopic belt and a porous belt, and between the upper dewatering belt and the lower dewatering belt, an impurity collecting part of a storage tank, an impurity discharge part of a separation filter, and the Impurities discharged through the 1 cyclone separator are supplied to a thickness of 30 to 100 mm, the rollers are provided with 2 to 10 rollers in a zigzag direction, and the liquid component separated by the impurity separator is supplied to the storage tank, The urea water separated by the solid-liquid separation means may be supplied to the storage tank.

In addition, the present invention comprises the steps of (i) supplying water to the stirrer and performing stirring; (ii) preparing urea water by supplying urea after the stirring of the water is started; (iii) supplying the urea water prepared in the agitator to a storage tank and storing it for 1 to 3 days; (iv) separating the supernatant of the urea water stored for 1 to 3 days, and then supplying it to a solid-liquid separation means to remove the solid material; And (v) provides a urea water manufacturing method using the urea water manufacturing apparatus comprising the step of supplying the urea water from which the solid material is removed to a storage tank.

According to an embodiment of the present invention, as the urea water is produced at a low temperature, the generation of impurities can be minimized, and thus, it is possible to provide a method for producing urea water that can increase the lifespan of the SCR device.

In addition, the present invention can provide a method for producing urea water capable of maximizing the lifespan of a filter by aging the manufactured urea water in a storage tank, thereby separating foreign substances generated during the production of urea water.

In addition, the present invention can provide a urea water manufacturing method capable of maximizing the life of the SCR device by filtering the urea water manufactured by a low-temperature method to minimize impurities and foreign substances in the urea water.

The effect according to the present invention is not limited by the contents exemplified above, and more various effects are included in the present invention.

1 shows the overall configuration of the urea water manufacturing apparatus according to an embodiment of the present invention.
Figure 2 schematically shows a stirrer according to an embodiment of the present invention.
3 shows a centrifugal separator according to an embodiment of the present invention.
4 is a view showing the upper surface of the centrifugal separator according to an embodiment of the present invention.
5 shows a separation filter according to an embodiment of the present invention.
6 shows the principle of the impurity separator according to an embodiment of the present invention.

Hereinafter, various embodiments will be described in more detail with reference to the accompanying drawings. The embodiments described herein may be variously modified. Certain embodiments may be depicted in the drawings and described in detail in the detailed description. However, the specific embodiments disclosed in the accompanying drawings are only provided to facilitate understanding of the various embodiments. Therefore, the technical idea is not limited by the specific embodiments disclosed in the accompanying drawings, and it should be understood to include all equivalents or substitutes included in the spirit and scope of the invention.

Terms including an ordinal number such as 1st, 2nd, etc. may be used to describe various components, but these components are not limited by the above-mentioned terms. The above terminology is used only for the purpose of distinguishing one component from another component.

In this specification, terms such as "comprises" or "have" are intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof. When an element is referred to as being “connected” or “connected” to another element, it is understood that it may be directly connected or connected to the other element, but other elements may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

Meanwhile, as used herein, a “module” or “unit” for a component performs at least one function or operation. And “module” or “unit” may perform a function or operation by hardware, software, or a combination of hardware and software. In addition, a plurality of “modules” or a plurality of “units” other than a “module” or “unit” to be performed in specific hardware or to be executed in at least one processor may be integrated into at least one module. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In addition, in describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be abbreviated or omitted.

1 schematically shows an apparatus for producing urea water of the present invention.

The present invention is (a) a stirrer; (b) a storage tank for storing the urea water produced in the agitator for a certain period of time; And (c) relates to a urea water production apparatus comprising a solid-liquid separation means for purifying the urea water stored for a certain period in the storage tank.

The stirrer 100 is a part that mixes water and urea by mixing urea water, and a screw for stirring is formed inside a basically cylindrical body. In the case of the conventional stirrer for producing urea water, heated water is supplied to prevent the formation of ice due to the endothermic reaction of the urea water, and also has a means for heating and supplying the urea water in the stirrer. However, when the prepared urea water is heated, side reactions may occur and impurities such as burette and triuret may be formed, which is known to adversely affect the lifespan of the SCR device. Therefore, in the present invention, by controlling the amount of urea supplied to the stirrer, the temperature drop due to endothermic reaction is minimized and the inside of the stirrer is maintained at a constant temperature to minimize the generation of ice and side reaction products such as burette and triuret. can be minimized.

To this end, the stirrer, a cylindrical body; a rotating shaft installed through the lower end of the stirring body to rotate the stirring screw installed in the lower part of the cylindrical body; a screw for stirring connected to one end of the rotating shaft and installed in the lower part of the body; a rotating motor installed at the lower end of the rotating shaft and rotating the rotating shaft and the agitating screw; a water supply part formed on the upper part of the cylindrical body; a urea supply unit installed on the side of the water supply unit; And it may include a urea water outlet installed in the lower portion of the cylindrical body (see FIG. 1).

The cylindrical body 110 is a portion in which the water and urea react to generate urea water, and has a space in which the water, urea, and the generated urea water can be stored. In addition, it is preferable that the cylindrical body 110 is made of iron, stainless steel, aluminum, copper, or an alloy containing the same so that the endothermic reaction can be smoothly performed inside the cylindrical body so that heat exchange can occur at a high speed. As described above, the reaction in which urea and water are mixed to produce urea water is an endothermic reaction, and as urea is added to the water, the temperature of the water may drop. At this time, if heat exchange is not performed in the cylindrical body, water inside the cylindrical body may be changed to ice, which may result in the cessation of the reaction. Therefore, it is preferable that the cylindrical body 110 is made of a metal having high thermal conductivity so that heat required for the endothermic reaction can be rapidly exchanged.

The rotating shaft 120 may have a screw 130 for stirring connected to one side and a motor connected to the other side so that the screw 130 for stirring can be rotated within the cylindrical body 110 . In this case, the rotating shaft 120 may be installed through the lower portion of the cylindrical body 110 , and accordingly, the agitating screw 130 may be positioned under the cylindrical body 110 . In the case of a general stirrer, the rotating shaft is installed through the upper part of the cylindrical body. However, in the present invention, it is preferable to install the rotating shaft 120 in the lower part of the main body so that it can operate normally even when the water is frozen without disturbing the flow of water generated by the stirring screw 130 . That is, even when the water for urea water production freezes, the water freezes from the surface, so the rotating shaft 120 can rotate without being disturbed by the ice. can

The stirring screw 130 is connected to one end of the rotating shaft 120 to mix the urea water inside the cylindrical body 110, and a screw 130 having 2 to 10 blades may be used. In the case of the existing screw, since it is simply installed for mixing, most are operated to form a flow below the agitator for mixing efficiency. In particular, when a conventional stirrer whose rotating shaft passes through the upper part of the main body forms an upward flow, an additional load can be applied to the rotating shaft, thereby reducing the efficiency of the rotating shaft, so most stirrers are installed to form a downward flow.

However, in the case of the present invention, the rotating shaft 120 is installed through the lower portion of the stirrer body 110, and the screw 130 for stirring is also located at the lower portion, so it is possible to install it to form an upward flow, Accordingly, an upward flow may be formed in the center of the cylindrical body 110 by rotation of the agitating screw 130 . In this case, even when the temperature of the urea water drops, a continuous flow is formed to prevent the water from freezing, and even when some ice is formed, the ice can be crushed by the rotation of the screw 130 . It is possible to minimize the non-reaction caused by That is, in the case of the conventional downward flow, the mixing of urea water on the water surface is not complete, so ice is formed on the water surface and at the same time the rotation of the rotation shaft is disturbed due to the ice formed in this way, so that the mixing efficiency may decrease sharply. Due to the flow of the water, not only the water surface is completely mixed, but even if some ice is generated, the rotation of the rotating shaft cannot be affected. , it is possible to minimize the decrease in efficiency and change in composition due to ice.

In addition, as described above, when ice is generated, the screw 130 must simultaneously perform a role of pulverizing it, so it is preferable to be manufactured to be thicker than a conventional mixing screw. Specifically, in the case of a conventional screw, the front end of the rotor blade is thickly manufactured, and the cross section is manufactured to have a streamline or droplet shape for rotational efficiency. The risk of breakage may increase if ice is introduced. Therefore, in the case of the present invention, it is preferable to make the cross section of the rotary blade in a streamlined shape, and to make the front end sharp and sharp so that the ice can be crushed while maintaining the efficiency above a certain level.

The water is used as a solvent for dissolving the urea, and it is preferable to use ultrapure water from which impurities are removed so as not to affect the catalyst of the SCR device.

The ultrapure water is obtained by separating only water using multi-stage distillation of water, and then removing impurities using an ion exchange membrane or reverse osmosis membrane. Accordingly, the life of the catalyst can be increased.

The urea is a compound having a molecular structure of NH2CONH2 and is industrially manufactured by reacting ammonia with carbon dioxide.

The motor 140 is installed to rotate the rotating shaft and, as a result, to rotate the stirring screw installed at one end of the rotating shaft, a generally used electric motor may be used.

A water supply unit 150 and a urea supply unit 160 may be installed on the upper portion of the cylindrical body. In particular, in the case of the urea, it is preferable that the urea supply unit 160 is installed on the water surface inside the main body by being installed on the upper part of the main body because the water is supplied at a constant rate after the supply of the water to reduce freezing of the water inside the main body. In addition, the urea water manufactured in the main body may be discharged through the urea water outlet 170 located in the lower part of the main body.

Urea may be supplied to the agitator 100 at a rate of 0.1 to 0.5 kg/min per 100 kg of water. As described above, the reaction of producing urea water by mixing water and urea corresponds to an endothermic reaction, and when urea is mixed at a high speed, water may freeze and ice may occur due to this endothermic reaction. Therefore, by supplying the urea at an appropriate rate, it is possible to minimize the freezing of water during the production of the urea water. At this time, when the supply amount of the urea is less than 0.1 kg/min, it takes a lot of time to prepare the urea water of the desired concentration, so it is uneconomical, and when supplied at a rate exceeding 0.5 kg/min, the water may freeze due to an endothermic reaction can

In the case of the agitator 100, the body is made of a material having high thermal conductivity to enable heat exchange, but when a large amount of urea water is manufactured, local freezing may occur, which does not facilitate heat exchange. In addition, the manufactured urea water must be mixed and discharged in a liquid state, so the inside of the stirrer may include a temperature control means 180 to maintain a constant temperature.

In the case of a basic stirrer for urea water production, part of the liquid inside the stirrer is taken out and then heated and supplied to maintain the temperature inside the stirrer, but in this case, the liquid is heated to a high temperature and recycled to the stirrer. Accordingly, the generation of impurities may increase during the heating process of the discharged liquid.

Therefore, in the present invention, by locating the temperature control means 180 inside the stirrer body, the inside of the stirrer can be maintained at a constant temperature, and local cooling and heating are minimized, thereby minimizing the generation of impurities and freezing. .

To this end, the temperature control means 180 is spirally formed inside the cylindrical body, one end is connected to the lower part of the cylindrical body, the lower end is a temperature control pipe connected to the upper part of the cylindrical body; a heat supply unit for supplying heat having a constant temperature to the temperature control pipe; And it may include a temperature control unit for heating or cooling the heat medium.

The temperature control pipe is a pipe-type structure installed inside the cylindrical body, and a heat medium to be described later is circulated therein, and may serve to maintain a constant temperature of the agitator. At this time, the temperature control pipe is preferably manufactured to have a spiral so as not to obstruct the upward flow generated by the stirring screw, and the diameter of the spiral formed by the temperature control pipe is 1/4 of the diameter of the body. It can be ~3/4. When the spiral diameter of the temperature control pipe is less than 1/4 of the body diameter, the temperature control pipe is located at the center of the stirrer and may interfere with the upward flow generated by the screw, exceeding 3/4 In the case of having a diameter, it may be difficult to accurately control the temperature of the center because the temperature control pipe is close to the wall surface (see FIG. 2 ).

The fruit may be circulated inside the temperature control pipe. The heat medium refers to a liquid having a constant temperature, which is heated or cooled and circulated, and refers to a liquid that accelerates the movement of heat. In the present invention, water or heat medium oil can be used as the heat medium, and the inside of the stirrer can be reduced below the freezing point by endothermic reaction and low temperature must be maintained, so the heat medium oil can be used as the heat medium.

In addition, since one end of the temperature control pipe is connected to the lower part of the cylindrical body, and the lower end is made to be connected to the upper part of the cylindrical body, it is preferable that the fruit is introduced from one end of the temperature control pipe and discharged as a tea burner. When the fruit is introduced from the lower end of the temperature control pipe, air may be introduced into the temperature control pipe, and thus the efficiency of the temperature control pipe may be reduced.

The heat medium supply unit can be supplied to the temperature control pipe inside the stirrer to maintain the heat medium at a constant temperature by including a temperature control unit therein as a part for supplying the heat by pressurizing the heat medium to the temperature control pipe. To this end, the temperature control unit may heat or cool the fruit, including a heating means and a cooling means.

Looking at this in detail, when the stirrer is operated, water is preferentially supplied to the inside of the stirrer, and at this time, the water has a temperature of 20 to 30 ° C. It is preferable to operate the means, and to cool the inside of the stirrer to 0-5 °C.

After the cooling is completed, urea may be supplied to the water at a constant rate, and at this time, since an endothermic reaction is performed, the water may be cooled to less than 0° C. and frozen. Therefore, in this case, the inside of the stirrer can be maintained at -15 to 5 °C by supplying the fruit heated to 0 to 10 ° C through the temperature control pipe. Through this, side reaction products such as burette and triuret generated at high temperature can be minimized, and at the same time, freezing of water can be prevented so that urea water can be smoothly generated. In addition, in the case of general water, freezing may start at 0°C, but when it is mixed with the urea to form urea water, it may not freeze even below 0°C due to the freezing point lowering effect caused by the urea. Therefore, it is preferable to adjust the inside of the stirrer to an appropriate temperature according to the amount of the input element.

The temperature control means 180 is preferably capable of maintaining the temperature in the stirrer at -15 ~ 5 ℃. If the temperature in the stirrer is less than -15 °C, the urea water may be frozen, and if it exceeds 5 °C, the amount of side reaction products such as burette and triuret may increase.

As described above, the urea water synthesized in the agitator 100 may be stored for a certain time in the storage tank 200 . Even after the urea water is manufactured, a large amount of suspended matter may be generated due to unreacted urea and impurities. In addition, since an endothermic reaction is performed during the reaction, the inside of the stirrer is maintained at a constant temperature by the temperature control means 180 and small pieces of ice can float even when the ice is crushed using a screw for stirring. In the case of the existing urea water manufacturing method, since these floating substances are removed by using a filter, the efficiency of the filter is reduced, which requires a lot of cost for the manufacture of urea water. However, the present invention can maximize the efficiency of the filter to be described later by storing the produced urea water in the storage tank 200 for a certain period of time and removing the floating matter by sedimentation, and accordingly, the manufacturing cost of the urea water is also can be minimized

To this end, the storage tank includes a storage tank body; a urea water discharge unit formed at a lower portion of the storage tank body; a funnel-shaped impurity collecting unit connected to the lower end of the storage tank body; and a warming means surrounding the storage tank body and the outer circumferential surface of the impurity collecting part; A temperature maintaining means capable of maintaining the storage tank at a constant temperature may be included in the heat retention means.

The storage tank body is a part that is a place for storing the urea water, and may be manufactured in a size that can store the urea water with an internal volume of 1 to 20 tons. In addition, since the suspended matter of the urea water may settle in the lower portion of the storage tank, the sedimented impurities may be easily removed by forming a funnel-type impurity collecting part.

Looking at this in detail, the storage tank body may be formed in a cylindrical shape, and the impurity collecting part is manufactured in a funnel shape, and the upper part having the maximum diameter is manufactured to coincide with the cylindrical body, so that the lower end of the cylindrical body is the funnel shape It may be manufactured to coincide with the top of the impurity collecting part. In this case, the impurities in the storage tank settle to the lower end of the main body, and the impurities collecting part can be naturally collected in the lowermost part having a small diameter. In addition, a discharge port through which the impurities can be taken out is installed at the lowermost end of the impurity collecting unit, so it is possible to easily discharge the sedimenting impurities from the lower end of the impurity collecting unit without installing a special device in the storage tank body .

In addition, in the case of the outlet, it may be simply an outlet having a stopper or a valve, but it is formed at the lower end of the impurity collecting part, and the upper side is opened and is located inside the outlet body and the outlet body into which the sedimented impurities are introduced, and the sedimented impurities are removed It is preferable to include a melt feed screw that feeds in one direction.

The outlet may have an inlet installed at the upper side, and the inlet may be connected to the lowermost end of the impurity collecting unit. In the case of a general liquid, it can be smoothly discharged only through the inlet, but in the case of settled impurities, since it is in the form of sludge mixed with water, the rate of discharge to the outside is slow even if the inlet is simply opened, so discharge may be delayed. Therefore, it is preferable to connect the inlet to the lower end of the impurity collecting unit as described above, but install a transfer screw inside the main body of the outlet to transfer impurities in the form of sludge.

It may include a thermal insulation means surrounding the outer peripheral surface of the storage tank body and the impurity collecting part. In the case of the storage tank, the urea water must be stored for a certain period of time, and when a sudden temperature change or temperature rises in the urea water, a side reaction may occur and impurities may be formed. Therefore, it is preferable to install a heat-retaining means on the surface of the storage tank to store the number of urea in the storage tank in a constant peninsula. In this case, the thermal insulation means can be used without limitation as long as it is a thermal insulation means capable of maintaining the storage tank at a constant temperature, and it is preferable to use a nonwoven fabric or a foamable polymer made of a fibrous material such as glass fiber, rock wool, or polymer fiber. do.

In addition, it is more preferable to install a temperature maintaining means inside the heat retention means to maintain the temperature in the storage tank at -15 to 5°C. As described above, when the temperature of the urea water increases, side reaction products such as burette and triuret may be generated, and urea may be precipitated at a high temperature. In addition, since most of the storage tank is stored inside or outside the factory, the temperature may increase when the urea water is stored for a long period of time. Therefore, it is preferable to maintain the internal temperature by using the heat-retaining means and to store the urea water in the storage tank at a constant temperature using the temperature-maintaining means.

It is preferable that the storage tank 200 stores the urea water for 1 to 5 days to settle the impurities. If the urea water is stored for less than 1 day, unsettled impurities may be present, and if stored for more than 5 days, the cost may increase.

Residual impurities may be removed from the urea water stored for a certain period of time in the storage tank 200 and the impurities are settled through the solid-liquid separation means.

To this end, the solid-liquid separation means includes: a centrifugal separation means for primary separation of the urea water supplied from the storage tank; And it may include a separation filter for secondary separation of the number of urea that has passed through the separation filter.

The centrifugal separation means 300 is a means for removing residues in the urea water by using centrifugal force, and since it does not use a porous material such as a filter and can be operated for a long time, in order to increase the efficiency of the separation filter to be described later, the centrifugal separation means 300 It is preferable to use an expression separation means as the primary separation means (FIGS. 3 and 4).

The centrifugal separation means includes: a first cyclone separator in which the urea water discharged from the storage tank is supplied in a tangential direction and separates the solid material and the low specific gravity primary treated urea water by centrifugal force; and 2 to 20 pieces are arranged at equal intervals along the upper outer peripheral surface of the first cyclone separator, the number of primary treatment elements discharged from the first cyclone separator is supplied in a tangential direction, and the solid material with a large specific gravity and secondary treatment with a low specific gravity A plurality of second cyclone separators for separating the urea water by centrifugal force may be included (see FIG. 3 ).

The urea water from which the powder is separated by sedimentation in the storage tank as described above may be supplied to the first cyclone separator 310 . At this time, in the case of the urea water separated from the storage tank, as it is supplied (311) tangentially to the outer circumferential surface of the first cyclone separator, it rotates inside the first cyclone separator 310, and by this rotation, the specific gravity is high The solid impurities may be discharged (312) to the lower outlet along the outer surface of the cyclone. In addition, the liquid urea water having a low specific gravity is present in the center of the first cyclone separator, and the urea water having a low specific gravity existing in the center is supplied to the second cyclone separator 320 to perform secondary separation.

In addition, the urea water may not have sufficient pressure to operate the cyclone separator. In order to improve this, the urea water is preferably pressurized using a pressurizing means while being supplied from the storage tank to the solid-liquid separation means. The pressurizing means can be used without limitation as long as it is a means capable of pressurizing the urea water.

As described above, the urea water (the number of primary treated urea) separated in the first cyclone separator is supplied to the second cyclone separator 320 . At this time, the primary treatment urea water is supplied (321) in the tangential direction of the second cyclone separator to the same as the number of urea supplied from the first cyclone separator in the storage tank, rotates inside the second cyclone separator, and is subjected to centrifugal force. impurities can be removed. Thereafter, the secondary treated urea water after separation from the impurities may be discharged to the outside through the outlet 322 located at the upper portion of the second cyclone separator.

2 to 20 of the second cyclone separators 320 may be arranged along the outer peripheral surface of the upper portion of the first cyclone separator 310 (see FIG. 4 ). The second cyclone separator receives and processes the primary treatment urea water discharged from the first cyclone separator. However, since the primary treatment urea water has a lower pressure than the urea water supplied to the first cyclone separator and at the same time contains impurities having a small particle size, if a separator of the same size as the first cyclone separator is used, the efficiency is reduced can do. Therefore, by using the second cyclone separator having a smaller size than the first cyclone separator, it is possible to efficiently separate impurities of a small size even at a low pressure. In addition, in order to secure the processing capacity, it is preferable to use 2 to 10 in an array.

In addition, since the second cyclone separator 320 re-injects ( 323 ) the impurities discharged into the first cyclone separator, it is preferably located above the first cyclone separator. When the second cyclone separator is located at the middle or lower end of the first cyclone separator, additional equipment is required to transport the impurities discharged from the second cyclone separator to the upper part of the first cyclone separator, and pressurization for spraying is required after transportation There may be an increase in the processing cost.

In addition, 2 to 20 of the second cyclone separators 320 may be arranged and used. When only one second cyclone separator is used, the size of the second cyclone separator increases in order to have the same treatment effect, so space utilization may be disadvantageous, and when 20 or more second cyclone separators are used, the manufacturing cost increases. In addition, the pressure inside the second cyclone separator may be lowered, thereby reducing the dust collection efficiency.

The internal volume ratio of the second cyclone separator 320 and the first cyclone separator 310 may be 1:2 to 1:100. When the sum of the internal volumes of the second cyclone separator is greater than the internal volume of the first cyclone separator, the internal pressure of the second cyclone separator is lowered, so that smooth separation may not be achieved. Therefore, it is preferable that the sum of the internal volumes of the second cyclone separator is smaller than the internal volume of the first cyclone separator, and when this is applied to each cyclone, the internal volume ratio of the second cyclone separator and the first cyclone separator is 1:2 to 1 : 100 is preferable. When the ratio of the volume is 1:2, the internal pressure of the second cyclone separator may decrease, so that the separation of impurities may not be smooth. costs may arise.

The impurities collected in the second cyclone separator are discharged 323 to the lower part of the second cyclone separator, and the impurities may be mixed with the urea water supplied to the first cyclone separator and supplied 311 . That is, the impurities collected in the solid-liquid separation means can be discharged 312 only through the lower portion of the first cyclone separator 310, and the amount of impurities discharged to the outside can be minimized due to the re-separation method of these impurities. .

Even if solid impurities are separated through the centrifugal separation means 300 , when the solid impurities are used as they are, the life of the SCR device may be shortened due to trace amounts of impurities. Therefore, it is possible to minimize the impurities in the solid phase by separating the urea water that has passed through the circular separation means 300 once more using the filter 400 .

To this end, the separation filter; Cylindrical separation filter body; a porous filter installed at the middle of the main body to spatially separate the upper part and the lower part of the main body; a urea water supply unit installed at a lower portion of the main body of the separation filter; a funnel-shaped waste collection unit connected to the lower end of the separation filter body; And it may include a urea water discharge unit installed on the upper portion of the separation filter body (see FIG. 5).

The cylindrical separation filter body 410 includes a porous filter 420, which will be described later, and is a part for allowing the urea water to flow from the bottom to the top so that impurities remain in the lower part of the porous filter. At this time, it is preferable that the separation filter body is manufactured in a cylindrical shape for the smooth flow of the urea water.

The porous filter 420 may be installed at the middle of the main body to spatially separate the upper part and the lower part of the main body. Through this, the urea water supplied from the solid-liquid separation means is introduced 430 through the lower portion, and high purity urea water separated from impurities is formed in the upper portion and discharged 450 to the outside of the body. In this case, the impurities separated from the urea water may be located in the lower part of the main body, and may be discharged to the outside through a waste collection unit to be described later by sedimenting to the lower part due to the effect of gravity. In the case of the impurity separation method using such gravity, the life of the porous filter can be maximized because the impurities separated by the porous filter settle to the lower part of the main body.

In addition, it is preferable to regenerate the porous filter 420 by supplying 460 urea water for backwashing even if the pores are clogged by the impurities. The impurities can block the pores of the filter and shorten the life of the filter, but this is only blocking in one direction. it is possible to do In addition, by manufacturing the porous filter to have a certain shape, it is possible to maximize the efficiency of the filter by increasing the flow amount of the urea water.

To this end, the porous filter may include a connection part connected to the middle part of the separation filter body; 2 to 20 protrusions formed in the center of the connection part; and a vibration generating unit connected to one side of the connection unit and vibrating the porous filter when supplying the urea water for backwashing (see FIG. 5 ).

The connection part 421 is manufactured in a circular shape and connects the separation filter body and the protrusion 422 to be described later. It can be made to be At the center of the connection part, protrusions to be described later are arranged at equal intervals to maximize the efficiency of the porous filter.

The protrusions 422 are made of the same material as the porous filter, and 2 to 20 pieces may be arranged at equal intervals in the central portion of the porous filter 420 . Through this, the surface area of the porous filter 420 can be significantly increased, thereby maximizing the filtering efficiency of the urea number. In addition, when the urea water passes through the protrusion 422 when passing through the porous filter, the impurities are concentrated in the lower portion of the protrusion to form sludge with a large size, so it can be easily dropped and separated. . In addition, in the backwashing process to be described later, if the backwashing urea water is supplied, the wall surface of the protrusion may be rubbed by pressure, so the impurities inside the protrusion may be easily aggregated and separated through the backwashing urea water and vibration. .

In addition, in order to perform the backwashing process more efficiently, a vibration generating unit may be included at one side of the connection unit. The vibration generating unit supplies vibration to the porous filter during the backwashing process, thereby accelerating the removal of the impurities, which can make the backwashing process more efficient.

A backwash urea water supply unit 460 may be installed at an upper portion of the filter body. As described above, when the porous filter is clogged by impurities, the separation efficiency of the urea water may be reduced. Therefore, in order to separate such impurities, urea water is supplied from the upper part of the main body, so that the impurities can be released to the opposite side of the filter, that is, to the lower part 440 of the main body.

A urea water outlet is formed in the upper portion of the filter body, so that the urea water that has passed through the porous filter can be transferred to the storage tank.

The impurities separated in the storage tank, the solid-liquid separation means and the separation filter are in the form of sludge containing a large amount of impurities, but the urea water also contains a large amount of urea water. can cause Therefore, it is possible to reduce the manufacturing cost of urea water by separating and recycling the liquid urea water from the sludge, and also it is possible to minimize the discharge amount of the sludge.

Impurities discharged through the impurity collecting unit of the storage tank, the impurity discharging unit of the separation filter, and the first cyclone separator are discharged through an impurity separator, the impurity separator comprising: an upper dewatering belt; lower dewatering belt; and a roller for pressing the upper dewatering belt and the lower dewatering belt.

As described above, the impurities discharged through the impurity collecting unit of the storage tank, the impurity discharging unit of the separation filter and the first cyclone separator constitute sludge, and urea water can be recovered by pressing and dewatering it. Therefore, by supplying the impurities in the form of sludge to the impurity separator, the liquid urea water can be dehydrated and recycled to the storage tank.

The impurities in the form of sludge separated as described above may be introduced into the impurity separator 500 to remove excess urea water. As the impurity separator, a dehydrator using a belt may be used, which will be described in detail as follows (see FIG. 6 ).

In the impurity separator, two belts are positioned at the upper and lower parts, and the sludge is compressed between the belts to perform dehydration. Among the belts, the lower dewatering belt may be installed with an inlet extending longer than that of the upper dewatering belt, and it is preferable to supply the sludge to this extension so that it is inserted between the belts.

The dewatering belt is preferably a belt manufactured by bonding a hygroscopic belt and a porous belt. In particular, a hygroscopic belt may be installed to contact the sludge. Through this, when the sludge is compressed, the urea water is absorbed by the hygroscopic belt, and the urea water absorbed by the hygroscopic belt can be discharged to the outside through the porous belt. The hygroscopic belt has a certain thickness and may be made of a nonwoven fabric or felt having a high hygroscopicity, and the thickness may be 5 to 10 mm. The porous belt is preferably used by perforating a belt formed of a polymer resin or fabric at regular intervals.

The roller is a device for dewatering the sludge by applying pressure to the upper and lower belts, and 2 to 10 rollers may be installed in a zigzag direction. Although the upper and lower belts were installed and compressed, in this case, the perforated portion of the belt was blocked by the rollers while passing between the rollers, so that the amount of dewatering was small compared to the high pressure. In order to improve this, the present invention arranges the rollers in a zigzag manner and allows the belt to pass therebetween, so that the surface of the belt in contact with the roller is one surface and the urea water can be discharged in the direction of the other surface that is not in contact. . In this installation method, less pressure is applied compared to the opposite roller, but the amount of discharged urea can be increased.

The sludge has a thickness of 30 to 100 mm and is supplied to the dewatering belt, and the dewatered sludge may have a thickness of 20 to 70 mm. The sludge may be thinned by the volume of the urea water as it undergoes a dewatering process. Therefore, it is preferable to be supplied with a thickness of 30 to 100 mm so that it can have a constant thickness even after dehydration. When the sludge is supplied with a thickness of less than 30 mm, the amount that can be dewatered for a certain period of time is reduced due to the thin thickness, and thus the efficiency may be reduced. .

When urea water is separated from the sludge as described above, the urea water can be recovered to the storage tank and recycled, and the separated sludge contains unreacted urea and other nitrogen compounds. can be recycled as

Hereinafter, the present invention will be described in detail through a method for producing urea water.

The present invention comprises the steps of: (i) supplying water to a stirrer and performing stirring; (ii) preparing urea water by supplying urea after the stirring of the water is started; (iii) supplying the urea water prepared in the agitator to a storage tank and storing it for 1 to 3 days; (iv) separating the supernatant of the urea water stored for 1 to 3 days, and then supplying it to a solid-liquid separation means to remove the solid material; And (v) relates to a urea water manufacturing method using the urea water manufacturing apparatus comprising the step of supplying the urea water from which the solid material has been removed to a storage tank.

The step (i) is a step of supplying water to the stirrer and then performing stirring, and then supplying ultrapure water as described above. This is a step of cooling to 0 ~ 5 ℃ while stirring.

After the cooling of the water is completed, urea water can be produced by supplying urea at a rate of 0.1 to 0.5 kg/min per 100 kg of water. At this time, since the urea water production reaction corresponds to an endothermic reaction, it is preferable to maintain a constant temperature in the stirrer using a temperature control means.

Since the urea water prepared as described above contains unreacted urea and side reactants, it can be supplied to a storage tank and stored for 1 to 3 days.

In this step, impurities contained in the urea water may be separated by sedimenting to the lower part of the storage tank, and only the liquid present in the upper layer may be supplied to a solid-liquid separation means to be described later to perform additional separation.

The urea water stored for a certain period of time in the storage tank and separated by sedimentation of impurities may be supplied to a solid-liquid separation means to separate solid impurities (solid substances). In this case, as the solid-liquid separation means, as described above, a centrifugal separation means using a cyclone and a separation filter using a porous filter may be used.

The urea water that has passed through the solid-liquid separation means may be stored in a storage tank, which may be packaged in a certain amount or taken out through a pipe or the like.

In addition, impurities generated in the storage tank, solid-liquid separation means, etc. may be discharged in the form of sludge, liquid urea water is recycled to the storage tank through the impurity separator, and the remaining sludge is recovered for fertilizer, wastewater treatment or feed, etc. can be recycled for the purpose of

In the above, preferred embodiments of the present invention have been illustrated and described, but the present invention is not limited to the specific embodiments described above, and it is common in the technical field to which the present invention pertains without departing from the gist of the present invention as claimed in the claims. Various modifications are possible by those having the knowledge of, of course, and these modifications should not be individually understood from the technical spirit or perspective of the present invention.

100: agitator
110: agitator body
120: rotation axis
130: screw for stirring
140: motor
150: mole supply unit
160: urea supply unit
170: urea water discharge unit
200: storage tank
300: centrifugal separator
310: first cyclone separator
311: urea water inlet
312: impurity discharge part
320: second cyclone separator
321: primary treated water supply unit
322: secondary treated water discharge unit
323: impurity discharge part
400: separation filter
410: separation filter body
420: porous filter
421: connection part
422: protrusion
430: urea water supply unit
440: impurity discharge part
450: urea water discharge part
460: urea water supply unit for backwashing
500: impurity separator

Claims (3)

(a) stirrer;
(b) a storage tank for storing the urea water produced in the agitator for a certain period of time; and
(c) solid-liquid separation means for purifying the urea water stored for a certain period in the storage tank;
In the urea water production apparatus comprising a,
The stirrer,
cylindrical body;
a rotating shaft installed through the lower end of the stirring body to rotate the stirring screw installed in the lower part of the cylindrical body;
a screw for stirring connected to one end of the rotating shaft and installed in the lower part of the body;
A rotary motor installed at the lower end of the rotary shaft to rotate the rotary shaft and the agitating screw;
a water supply part formed on the upper part of the cylindrical body;
a urea supply unit installed on the side of the water supply unit; and
a urea water outlet installed in the lower portion of the cylindrical body;
includes,
The stirring screw forms an upward flow from the center of the cylindrical body, and crushes ice generated when the water and the urea react,
The urea is supplied in 30 to 35 parts by weight relative to 100 parts by weight of water,
A temperature control means is included in the inside of the cylindrical body;
The temperature control means,
a temperature control pipe formed in a spiral shape inside the cylindrical body, one end connected to the lower part of the cylindrical body, and the lower end connected to the upper part of the cylindrical body;
a heat supply unit for supplying heat having a constant temperature to the temperature control pipe; and
a temperature control unit for heating or cooling the fruit;
includes;
the temperature control pipe is formed in a spiral shape having a diameter of 1/4 to 3/4 of the diameter of the cylindrical body;
The cylindrical body can maintain a temperature of -15 to 5 ℃ by the temperature control means,
The storage tank is
Cylindrical storage tank body;
a urea water discharge unit formed at a lower portion of the storage tank body;
a funnel-shaped impurity collecting unit connected to the lower end of the storage tank body; and
a thermal insulation means surrounding the storage tank body and the outer peripheral surface of the impurity collecting part;
includes;
a temperature maintaining means capable of maintaining the storage tank at a constant temperature is included in the heat retention means;
The solid-liquid separation means,
a centrifugal separation means for primary separation of the urea water supplied from the storage tank; and
a separation filter for secondary separation of the urea water that has passed through the centrifugal separation means;
includes,
The centrifugal separation means,
a first cyclone separator in which the urea water discharged from the storage tank is supplied in a tangential direction and separates the solid material having a large specific gravity and the primary treated urea water having a low specific gravity by centrifugal force; and
2 to 20 are arranged at equal intervals along the upper outer circumferential surface of the first cyclone separator, and the number of primary treatment elements discharged from the first cyclone separator is supplied in a tangential direction, and a solid material with a large specific gravity and a secondary treatment element with a low specific gravity a plurality of second cyclone separators for separating water by centrifugal force;
includes,
The lower outlet of the second cyclone separator is tangentially connected to the upper portion of the first cyclone separator,
The solid material separated in the second cyclone separator is supplied to the upper part of the first cyclone separator and mixed with the urea water inside the first cyclone separator and separated,
The separation filter;
Cylindrical separation filter body;
a porous filter installed at the middle of the main body to spatially separate the upper part and the lower part of the main body;
a urea water supply unit installed at a lower portion of the main body of the separation filter;
a funnel-shaped impurity discharge unit connected to the lower end of the separation filter body; and
a urea water discharge unit installed on the upper part of the separation filter body;
includes;
A backwash urea water supply unit for backwashing the separation filter by supplying urea water from a storage tank is installed on the upper part of the separation filter body,
The porous filter,
a connection part connected to the middle part of the separation filter body;
2 to 20 protrusions formed in the center of the connection part; and
a vibration generating unit connected to one side of the connection unit and vibrating the porous filter when supplying the urea water for backwashing;
includes,
Impurities discharged through the impurity collecting unit of the storage tank, the impurity discharging unit of the separation filter, and the first cyclone separator are discharged through the impurity separator,
The impurity separator,
upper dewatering belt;
lower dewatering belt; and
a roller compressing the upper dewatering belt and the lower dewatering belt;
includes;
The upper dewatering belt and the lower dewatering belt are belts manufactured by bonding a hygroscopic belt and a porous belt,
Between the upper dewatering belt and the lower dewatering belt, the impurity collecting part of the storage tank, the impurity discharge part of the separation filter, and the impurities discharged through the first cyclone separator are supplied to a thickness of 30-100 mm,
As for the roller, 2 to 10 rollers are installed in a zigzag direction,
The liquid component separated in the impurity separator is supplied to the storage tank,
The urea water separated by the solid-liquid separation means is a urea water production apparatus, characterized in that supplied to the storage tank.
delete (i) supplying water to the stirrer and performing stirring;
(ii) preparing urea water by supplying urea after the stirring of the water is started;
(iii) supplying the urea water prepared in the agitator to a storage tank and storing it for 1 to 3 days;
(iv) separating the supernatant of the urea water stored for 1 to 3 days, and then supplying it to a solid-liquid separation means to remove the solid material; and
(v) supplying the urea water from which the solid material is removed to a storage tank;
A method for producing urea water using the urea water production apparatus of claim 1, comprising a.

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