Electrolysis apparatus for producing chlorine dioxide with high performance

Abstract

An electrolysis apparatus for producing chlorine dioxide, comprising an electrolytic cell for producing chlorine dioxide, a storage tank for receiving the produced chlorine dioxide, and a temperature control system including a coolant supply unit for providing a coolant, a directional valve, a cooling tank and a helical circulation channel. Each cooling tank is configurated to receive the electrolytic cell or the storage tankand is provided with the helical circulation channel surrounding the electrolytic cell or the storage tank. The directional valve is used to switch the flow of the coolant, so as to control the coolant to pass through the helical circulation channel surrounding the storage tank only, or thorugh the helical circulation channels surrounding the storage tank and the electrolytic cell sequentially. Thus, the electrolysis apparatus of the present invention can produce chlorine dioxide with high performance.

Description

FIELD OF THE INVENTION

The present invention is related to an electrolysis apparatus for producing chlorine dioxide with high performance via electrolysis and especially has a temperature control system that can assist the electrolysis apparatus to produce chlorine dioxide with high performance

BACKGROUND OF THE INVENTION

The electrolysis apparatus is conventionally used in metallurgy and refining, used to form a variety of gain coating on the surface of a processing object, or used to produce a variety of kinds of gas via electrochemical mechanisms.

In view of the development in producing chlorine dioxide with electrolysis, a number of manufacturers have developed a variety of improvements for the production of chlorine dioxide. The method of producing chlorine dioxide has been widespread gradually since LINDSTAEDT (USA) firstly published electrolysis technology for producing chlorine dioxide by using salt as a raw material in 1982. After analyzing various electrolysis methods, it is found that the three critical factors are very important for electrolysis. The three critical factors during the productive process regulate the electricity, timing control of the concentration for electrolysis, and temperature control. In other words, obtaining the optimal parameters respectively for the above three critical factors is important to obtain chlorine dioxide with ideal quality and process for production with high performance.

In order to prevent the temperature from rising too high during electrolysis, the peripheries of an electrolytic cell is usually provided with a cooling device as shown in FIG. 7. The electrolytic cell 120 is configurated in the case body 132. The lower-left of the case body 132 has the cooling water inlet 135 and the upper-right of the case body 132 has the cooling water outlet 136. The cooling water flows in the case body 132 via the cooling water inlet 135 and then flowed out through the cooling water outlet 136. Overall, the cooling water flows via one end of the case body and flows out via the other end of it. However, such arrangement would obviously cause the formation of much dead space in the case body, where the cooling water is unable to get access to easily. Therefore, it is ineffective and power wasting because the cooling water must be flowed by long and lasting pumping.

Moreover, after the process of electrolysis is complete, the temperature of the storage tank used for receiving the finished product of chlorine dioxide in a gas-liquid mixing form would rise because of the heat convection of the external environment. Since the boiling point of chlorine dioxide is 11° C., the finished product of chlorine dioxide in a gas-liquid mixing form in the storage tank would be gasified due to the rising of temperature. Producing chlorine dioxide via electrolysis and reducing the same via gasification at the same time is an undesirable phenomenon. Such phenomenon will not only reduce the concentration of chlorine dioxide and result in reducing production, but also it will take much more time to proceed the electrolysis. When time for the process of electrolysis is unexpectedly increased, the optimal parameters of the three critical factors described above would be changed, so as to result in the poor performance. It will render the quality of the produced chlorine dioxide unstable. Besides, since it is required to increase more power supply, it would shorten the expected use time of the electrode members for electrolysis.

SUMMARY OF THE INVENTION

In order to solve above problems, the present invention provides an electrolysis apparatus for producing chlorine dioxide with high performance. The present invention includes an electrolytic cell for producing chlorine dioxide; a storage tank for receiving the produced chlorine dioxide; and a temperature control system, including a coolant supply unit for providing a coolant, a directional valve; each cooling tank configurated to receive the electrolytic cell or the storage tank; and a helical circulation channel. The cooling tank has a coolant storage space formed between the cooling tank and the electrolytic cell and between the cooling tank and the storage tank respectively; wherein each cooling tank has a coolant inlet and a coolant outlet at lower side and upper side respectively, so as to supply the coolant into it for exchanging heat; in order to exchange heat substantially and completely, each coolant storage space is provided with the helical circulation channel surrounding the peripheries of the electrolytic cell and the storage tank respectively for providing helically circular flow path, and the coolant that flows into it flows substantially in a helically circular way from bottom to top and surrounding the peripheries of the electrolytic cell and the storage tank respectively, thereby achieving the expected cooling effect.

The directional valve is controlled to be at a first position or at a second position, so as to switch the flow direction of the coolant. When the directional valve is switched so as to guide the flow direction of the coolant, the coolant can be passed through the coolant tank of the storage tank only, or be passed through the coolant tanks of the storage tank and the electrolytic cell respectively. By means of the helically circular flow of coolant, the electrolytic cell and the storage tank can exchange heat entirely and substantially, so that the temperature-control could be maintained stably within a preset range. Thus, the electrolysis apparatus of the present invention can produce chlorine dioxide with high performance.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view showing a first preferred embodiment of an electrolysis apparatus of the present invention.

FIG. 2 is a schematic view showing the electrolysis apparatus in FIG. 1 that is in operation, where the coolant flows through the storage tank in a helically circular way.

FIG. 3 is another schematic view when the electrolysis apparatus in FIG. 1 operates showing the coolant is flowed through the storage tank and the electrolytic cell in a way of helically circular flow at the same time.

FIG. 4 is a schematic view showing a second preferred embodiment of the electrolysis apparatus of the present invention.

FIG. 5 is a schematic view showing the electrolysis apparatus in FIG. 4 operates.

FIG. 6 is another schematic view when the electrolysis apparatus in FIG. 4 that is in operation.

FIG. 7 is a schematic view of the electrolytic cell of prior art.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The embodiments of the present invention are described in details as follows in accordance with accompanying figures. The same symbol in each figure indicates the same or equivalent members.

Refer to FIGS. 1-3 which show a first preferred embodiment of an electrolysis apparatus of the present invention. The electrolysis apparatus includes an electrolytic cell 10 for producing chlorine dioxide (ClO₂); an electronic control unit (ECU; 50) for supplying positive electricity and negative electricity to anodes 15 and cathodes 16 of the electrolytic cell 10 respectively; a storage tank 30 in which proper amount of water is stored in advance and is provided with a gas-liquid mixing mechanism (not shown) and the air extracting pump 33; and a temperature control system. The air extracting pump 33 is connected with the chlorine dioxide output tube 13 and the chlorine dioxide outlet 12 of the electrolytic cell 10 in turn, so as to extract the produced chlorine dioxide from the electrolytic cell 10. The produced gas of chlorine dioxide and the stored water are mixed by the gas-liquid mixing mechanism (not shown), so as to form a solution of chlorine dioxide. The temperature control system includes a coolant supply unit 70, and a cooling tank (20, 40) which is configurated to receive the electrolytic cell 10 or the storage tank 30.

An electrolytic cell is usually be classified into a box-shaped cell with a rectangular cross-section in an axial direction and a circular-shaped cell with a circular cross-section in an axial direction. The electrolytic cell of present invention is designed to be a circular-shaped cell. The circular-shaped cell has many advantages as follows. It is able to provide a cylindrical electrolytic separating membrane and a cylindrical mesh electrode components (not shown) therein. With the mechanical advantage of the circular cross-section in the axial direction, the circular-shaped cell could provide better mechanical strength to reduce thickness of the body of the electrolytic separating membrane and the electrode components. In addition to cost savings, it also has the advantage of structural simplification (without the need of using rigid reinforcing member), by which the circular-shaped cell further can reduce the impedance of electrolytic current and flow of electrolyte and the volume of the electrolytic foam. Moreover, the body of the cylindrical anode and cathode also can be configurated concentrically and equidistantly with each other within the electrolytic cell, so as to be energized uniformly without any dead space, which may improve the efficiency of electrolysis and prevent electrolysis from the formation of calcified dirt due to dead space in which the power supplying fails.

The electrolytic cell 10 and the storage tank 30 both have the electrolytic cell body 11 and the storage tank body 31 with circular cross-section in an axial direction respectively. Each cooling tank (20, 40) has the cooling tank body (21, 41) for receiving the electrolytic cell body 11 and the storage tank body 31. Each coolant storage space (26, 46) is formed between each cooling tank body (21, 41) and each electrolytic cell body 11 and between each cooling tank body (21, 41) and each storage tank body 31 respectively. The coolant storage space (26, 46) is usually fully filled with coolant. The lower right side and upper left side of the cooling tank body (21, 41) have the coolant inlet (22a, 42a) and the coolant outlet (22b, 42b) in the form of off-centre and protruding radially respectively for the coolant to flow through for heat exchange. Moreover, the interior of each coolant inlet (22a, 42a) is provided with the inlet check valve (not shown) to prevent the coolant that flows into the cooling tank body (21, 41) from flowing in an opposite direction.

In order to exchange heat substantially and completely, each coolant storage space (26, 46) within the cooling tank (20, 40) are provided with the helical circulation channel (24, 44) surrounding the peripheries of the electrolytic cell and the storage tank respectively thereby providing helically circular flow path. Thus, the coolant that flows into the coolant storage space (26, 46) flows substantially in the helically circular way from bottom to top while surrounding the electrolytic cell body 11 and the storage tank body 31 respectively.

Each helical circulation channel (24, 44) has the helically surrounding member (23, 43) that surrounds the peripheries of the electrolytic cell body 11 and the storage tank body 31 respectively from the position corresponding to the coolant inlet (22a, 42a) axially to the coolant outlet (22b, 42b).

Each cooling tank (20, 40) is provided with the temperature controlling sensor (25, 45). When the temperature controlling sensor detects that the measured temperature reaches the preset value, it will provide information to the electronic control unit 50, and then the coolant supplying pump 73 will provide coolant to the cooling tank for cooling by the order sent from the electronic control unit 50. Since the operating temperature for electrolysis of chlorine dioxide is ranged between 45 and 65° C., the temperature controlling sensor 25 provided on the electrolytic cell 10 has the temperature range between 35° C. to 65° C. Since the boiling point of chlorine dioxide is 11° C., the temperature controlling sensor 45 provided on the storage tank 30 has the temperature range between 5° C. to 10° C.

The coolant supply unit 70 includes the coolant storage tank 74 for storing the coolant, the cooling machine 71 for cooling and the coolant supplying pump 73 for pumping the coolant outwardly. In order to maintain the condition of low temperature control for the storage tank 30, the interior of the coolant storage tank 74 for storing the coolant has the temperature range between 3° C. to 9° C. controlled by the cooling machine 71.

Since the temperature of the electrolytic cell 10 and the storage tank 30 would rise at the same time during the process of electrolysis, in order to solve this problem, the better solution is described as follows: the coolant is firstly passed through the helical circulation channel surrounding the storage tank 30, and then passed through the helical circulation channel surrounding the electrolytic cell 10 for cooling in series, and the temperature controlling range of the storage tank 30 to be lower than that of the electrolytic cell 10 is set. The best solution is described as follows: the directional valve 47 that can change the flow of the coolant is provided between the electrolytic cell 10, the storage tank 30 and the coolant storage tank 74. The directional valve 74 is preferably actuated by electromagnetic means or a motor, so as to be controlled automatically by the electronic control unit 50. The directional valve is preferably in a form of three ways and two positions, and this form is easily commercially available. The three ways of the directional valve are respectively connected with coolant reflux port 72b of the coolant storage tank 74, the coolant outlet 42b of the cooling tank 40, and coolant inlet 22a of the cooling tank 20. The directional valve in a form of two positions represents the first position and the second position. The directional valve 47 normally is at the first position and the directional valve 47 can be controlled automatically to be changed to the second position by the electronic control unit 50. When the directional valve 47 is at the first position, the coolant is passed through the helical circulation channel surrounding the cooling tank 40 of the storage tank 30 only (shown in FIG. 2). When the directional valve 47 is at the second position, the coolant is passed through the helical circulation channel surrounding the cooling tank 40 of the storage tank 30 first, and then passed through the helical circulation channel surrounding the cooling tank 20 of the electrolytic cell 10 (shown in FIG. 3).

The operation of the present invention is described as follows. Firstly, the water is poured into the storage tank 30 via the water inlet (not shown). If the temperature controlling sensor 45 provided in the storage tank 30 detects that the temperature at this time is higher than the preset value, the temperature controlling sensor 45 would send a signal to the electronic control unit 50, thereby making the coolant supplying pump 73 to pump the coolant for cooling. Then, the coolant flowing into the cooling tank 40 cools the storage tank 30 entirely in a helically circular way along the direction indicated by the arrows (as shown in FIG. 2) until the temperature controlling sensor 45 stop sending the signal, and the process of maintaining constant temperature for the storage tank 30 is finished. Secondly, the process of electrolysis is in operation (not described here). During electrolysis, the produced gas of chlorine dioxide is pumped outwardly into the storage tank 30 along the chlorine dioxide output tube 13 via the chlorine dioxide outlet 12 by means of the air extracting pump 33. The produced gas of chlorine dioxide and the water are mixed by the gas-liquid mixing mechanism (not shown), so as to form chlorine dioxide solution. During the process of gas-producing of chlorine dioxide and gas-extracting of chlorine dioxide, if the electronic control unit 50 receives the signal from the temperature controlling sensor 45 showing that the temperature is rising, the above steps will be repeated, and the coolant will be passed to the helical circulation channel surrounding the cooling tank 40 of the storage tank 30 by the coolant supplying pump 73 for cooling.

Since the temperature of the electrolytic cell 10 continues rising during the process of electrolysis, if the electronic control unit 50 receives the signal from the temperature controlling sensor 25 showing that temperature is rising, the electronic control unit 50 will send a signal to make the directional valve 47 changed to the second position and make the coolant supplying pump 73 operated. The pumped coolant is passed the cooling tank 40 first and then passed to the directional valve 47 along the direction indicated by the arrow via the coolant outlet 42b of the cooling tank 40. Since the directional valve 47 is changed to the second position, the coolant is passed into the cooling tank 20 via directional valve 47 and the coolant inlet 22a of the cooling tank 20 sequentially, so as to cool the electrolytic cell 10 until the sending of the signal representing that temperature is rising from the temperature controlling sensor 25 is stopped. At this time, the coolant supplying pump 73 is also stopped pumping by the electronic control unit 50.

Refer to FIGS. 4-6, in which a second preferred embodiment of the present invention is shown. The process of electrolysis is processed step by step as follows. The first step involves a feeding stage for sending the electrolyte into the electrolytic cell and sending water into the storage tank. The second step involves a waiting stage during the electrolysis. The third stage involves an arranging stage for discharging electrolytic residues, cleaning the electrolytic cell, and releasing solution of chlorine dioxide. Among these three stages, the most time-taking stage is the waiting stage (electrolysis) that takes ninety minutes. In other words, the “waiting time” for the entire process of producing chlorine dioxide will be ninety minutes. Thus, in order to solve this problem, the second preferred embodiment of the present invention is configurated by means of three storage tanks (30A, 30B, 30C) together with two electrolytic cells (10A, 10B). The advantage of this configuration is illustrated below.

In the second preferred embodiment of the present invention, in the operation of the first round, the storage tank 30A is arranged with the electrolytic cell 10A to cooperate together. When the process of electrolysis begins in the electrolytic cell 10A, the operation of the second round starts, in which the storage tank 30B is arranged with the electrolytic cell 10B to cooperate together. When the process of electrolysis begins in the electrolytic cell 10B, the water is supplied to the storage tank 30C which prepares the operation of the third round. The operation of the first round completes at the time when the filling of water in storage tank 30C is finished. The operation of the next round and so on would go on continually. Thereby, the entire operation process would proceed reasonably without the occurrence of the “waiting time (electrolysis)” described above.

Since the second preferred embodiment of the present invention is configurated by means of three storage tanks together with two electrolytic cells, the coolant inlet valves (19a, 19b, 49a, 49b, 49c) are provided at upstream of the coolant inlets of each electrolytic cell and each storage tank respectively, so as to separate the flow of each coolant inlet. The coolant inlet valves (19a, 19b, 49a, 49b, 49c) are normally closed and can be opened respectively by the electronic control unit 50.

The exemplary operation of the second embodiment of the present invention is illustrated as follows. Referring to FIG. 5, when the temperature of electrolytic cell 10A is at upper limit, the temperature controlling sensor 25 would send a signal to the electronic control unit 50 (not shown) to open the coolant inlet valve 19a and change the directional valve 47 to the second position. At the same time, the electronic control unit 50 would automatically compare the temperature detected currently by each temperature controlling sensor 45 provided in each cooling tank (40A, 40B, 40C), and then the coolant inlet valve (for example, the coolant inlet valve 49a indicated by the arrow is opened in FIG. 5) of the cooling tank(s) with higher temperature would be opened. In this way, the coolant can be passed to the target position along the direction indicated by the arrow in FIG. 5 for cooling.

Another exemplary operation of the second embodiment is illustrated as follows. Referring to FIG. 6, the coolant is passed sequentially into the cooling tank 40B and the cooling tank 20B for cooling. Thus, it is determined that the directional valve 47 is changed to the second position and the two coolant inlet valves (19b, 49b) are opened. Thus, the coolant can be passed to the target position along the direction indicated by the arrow.

The progress, the advantages, the benefit, and the industrial value of the present invention are illustrated as follow. According to the present invention, because the coolant that is passed into the cooling tank (20, 40) can be flowed in a helically circular way from bottom to top and surrounding the peripheries of the electrolytic cell 10 and the storage tank 30 respectively, a thorough heat exchange is possible. Besides, since the directional valve 47 can be switched to guide the flow direction of the coolant, the coolant can be passed through the coolant tank 40 of the storage tank 30 only or be passed through the coolant tanks (40, 20) of the storage tank 30 and the electrolytic cell 10 respectively. By means of such unique and entire circulation for the flow of coolant, it is able to control the temperature of the electrolytic cell 10 and the storage tank 30 at the best state. Under such temperature control, the electrolytic cell 10 can produce stably gas of chlorine dioxide with high-quality at the preset power parameters. After the produced gas of chlorine dioxide with high-quality is passed into the storage tank 30 and mixed to form the chlorine dioxide solution, under such temperature control, its concentration can be quickly increased to the target value, and thus the operation of the electrolytic cell 10 can be completed at preset time or before the preset time. By means of the cooperation of the electrolytic cell 10 and the storage tank 30, it is not only able to slow the qualitative change of the components of the electrolytic cell 10 and thus make the electrolytic cell 10 more durable, but it is also able to produce higher amount and higher purity of chlorine dioxide in comparison with the prior art.

Moreover, in prior art, it is required for a conventional cooling device of the electrolytic cell to pump cooling water continually for a long time (shown in FIG. 7). In comparison, in the present invention, the coolant supplying pump 73 is usually in the state of standby and would not be in operation unless it is required for cooling. When it is required for cooling, the coolant supplying pump 73 will be operated to pump the coolant. Thus, power supply required for the apparatus of the present invention could be significantly reduced.

The disclosure mentioned above together with and the accompanying drawings illustrate the present invention. Although the embodiments of the present invention have been described in details, many modifications and variations still might be made by those skilled in the art from the teachings disclosed hereinabove. Therefore, it should be understood that any modification and variation conforming to the spirit of the present invention are regarded to fall into the scope defined by the appended claims.

Claims

1. An electrolysis apparatus for producing chlorine dioxide with high performance, comprising:

an electrolytic cell, for producing chlorine dioxide;

a storage tank, for receiving the produced chlorine dioxide; and

a temperature control system, including a coolant supply unit for providing a coolant, a directional valve, a cooling tank and a helical circulation channel, wherein each cooling tank is configurated to receive the electrolytic cell or the storage tank and is provided with the helical circulation channel surrounding the electrolytic cell or the storage tank; the directional valve is used to switch the flow of the coolant, so as to control the coolant to pass through the helical circulation channel surrounding the storage tank only, or to pass through the helical circulation channel surrounding the storage tank and the helical circulation channel surrounding the electrolytic cell sequentially.

2. The electrolysis apparatus according to claim 1, wherein each helical circulation channel has a helical surrounding member and surrounds outer peripheries of the electrolytic cell or the storage tank.

3. The electrolysis apparatus according to claim 1, wherein the directional valve is in a form of three ways and two positions.

4. The electrolysis apparatus according to claim 1, wherein the directional valve is actuated by electromagnetic means or a motor.

5. The electrolysis apparatus according to claim 1, wherein the coolant is passed through the cooling tank receiving the storage tank and is passed through the cooling tank receiving the electrolytic cell sequentially.

6. The electrolysis apparatus according to claim 1, wherein the storage tank configurated with the cooling tank is provided with a temperature controlling sensor having an temperature range between 5° C. to 10° C..

7. The electrolysis apparatus according to claim 1, wherein the electrolytic cell configurated with the cooling tank is provided with a temperature controlling sensor having an temperature range between 35° C. to 65° C.