JP4125833B2 - Ozone supply method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for supplying ozone, and more particularly to a method and apparatus for supplying ozone in a stable state to facilities using relatively high concentrations of ozone such as pulp bleaching and water treatment.
[0002]
[Prior art]
When supplying ozone to equipment that uses relatively high concentrations of ozone, such as pulp bleaching and water treatment, the concentration generated by the ozone generator is 6 to 7% (mass%, the same applies hereinafter), at most about 10%. The ozone is supplied after being concentrated to about 20%.
[0003]
However, ozone is a substance having self-decomposability and gradually decomposes into oxygen even at room temperature. However, when the temperature is high or the ozone concentration is high, decomposition tends to be accelerated. In addition, since the decomposition of ozone is an exothermic reaction, when the decomposition of ozone occurs and the temperature of that portion rises, the decomposition of ozone is further accelerated by the increase in temperature.
[0004]
Therefore, when ozone is decomposed in the pipe, the temperature of the decomposed portion is rapidly increased, and piping materials such as packing may be deteriorated by heat or melted to cause ozone leakage. Further, when ozone is decomposed and the ozone concentration is lowered, a situation in which, for example, pulp cannot be sufficiently bleached occurs at the place where ozone is used, and the operation may be interrupted suddenly.
[0005]
[Problems to be solved by the invention]
Conventionally, such ozone decomposition has been detected by measuring a decrease in ozone concentration with an ozone densitometer, but the ozone densitometer is expensive and its number and location are limited. Decomposition of ozone could not be detected quickly, and it was difficult to identify the position where decomposition occurred. Moreover, in order to suppress decomposition | disassembly of ozone, it is effective to cool the piping through which ozone flows, but enormous energy is required to cool the whole piping.
[0006]
On the other hand, the present inventors closely observed the behavior of ozone flowing in the piping in order to supply ozone to the user in a stable state. As a result, it has been found that ozone decomposition occurs frequently at the valves and flowmeters provided in the piping, and as a result of further detailed examination, in the part where the gas flow direction, pressure and flow velocity change It was confirmed that ozone decomposition was likely to occur.
[0007]
[Means for Solving the Problems]
The present invention has been made on the basis of the above-described new knowledge, and the ozone supply method of the present invention has, as a first configuration, a bent portion, a valve portion, and a flow meter portion in a pipe for supplying ozone. In addition, the present invention is characterized by measuring the temperature of the pipe containing the flow direction, pressure and flow velocity of the ozone-containing gas flowing in the pipe or the vicinity of the downstream side, and detecting the decomposition of ozone by the rise in the measured temperature.
[0008]
In addition, the second configuration of the ozone supply method of the present invention maintains the entire piping for supplying ozone in a state that does not exceed a predetermined temperature, for example, 40 ° C., and bends, valves, and flow rates in the piping. Measure the temperature of pipes in the measuring section and other parts where the flow direction, pressure, and flow rate of ozone-containing gas flowing in the pipe change or in the vicinity of the downstream side, and when the measured temperature exceeds the predetermined temperature, the temperature rises The portion is cooled to, for example, 20 ° C. or lower, preferably 0 ° C. or lower.
[0009]
Furthermore, the ozone supply device of the present invention includes a bent portion, a valve portion, a flow meter portion, and other portions where the flow direction, pressure, and flow velocity of the ozone-containing gas flowing in the piping change or downstream thereof. A temperature measuring means is provided in the vicinity of the side, and a cooling means for cooling the portion where the temperature measuring means is installed is provided.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a system diagram of a main part of an ozone supply pipe showing one embodiment of the present invention. The ozone supply pipe shown in the present embodiment shows a portion for measuring the flow rate of ozone supplied from an ozone supply source such as an ozone generator or an ozone concentrator, and the ozone is an inlet connected to the ozone supply source. It flows from the side pipe 11 through the flow meter 12 to the outlet side pipe 13 connected to the ozone consumption destination.
[0011]
In addition, the ozone supply pipe is installed in an environment that can maintain a state in which the whole does not exceed a predetermined temperature. That is, by selecting a place that is not exposed to direct sunlight, avoiding the vicinity of high-temperature equipment, or installing it indoors, preferably in an air-conditioned room, to prevent the pipe temperature from rising due to external factors. ing.
[0012]
The flow meter 12 is a so-called area flow meter, and displays the flow rate according to the height of the float 12a. Therefore, in order to install the flow meter 12 in the vertical direction, the horizontal inlet side pipe 11 and the inflow pipe 14 of the flow meter 12 and the horizontal outlet side pipe 13 and the outflow pipe of the flow meter 12 are installed. Between them, 90 degree elbows 16 and 17 are provided. The inlet side pipe 11 is provided with a pressure gauge (P) 18, and the outlet side pipe 13 is provided with a valve 19.
[0013]
In such a piping system, on the downstream side of the flow meter 12, the downstream side of the elbows 16 and 17, and the downstream side of the valve 19, temperature measuring means for measuring the surface temperature of each piping, for example, a thermocouple (TC). Measurement points 21a, 22a, 23a, and 24a for 21, 22, 23, and 24 are provided, respectively, and cooling for cooling the flow meter 12 part, the elbows 16 and 17 part, and the valve 19 part including each measurement point installation part. Jackets 31a, 32a, 33a and 34a constituting the means 31, 32, 33 and 34 are provided, respectively.
[0014]
The elbows 16 and 17 are bent portions in which the direction of gas flow changes, and the flow meter 12 changes in the direction of gas flow because it passes through the large-diameter float chamber 12b that houses the float 12a. The valve 19 is a portion where the gas flow direction, pressure, and flow velocity change depending on its function and structure.
[0015]
The cooling means 31, 32, 33, 34 include a cooling heat source (C) 31 b, 32 b, 33 b, 34 b that supplies a cooling medium such as air, water, various refrigerants, various low-temperature liquefied gases, and the thermocouples 21, 22. , 23, and 24, and regulators (TIC) 31d, 32d, 33d, and 34d that open and close the cooling valves 31c, 32c, 33c, and 34c, and the jackets 31a, 32a, 33a, and 34a. The controllers 31d, 32d, 33d, and 34d are arranged in the jackets that open the respective cooling valves and cover the temperature rising portions when the indicated temperatures of the corresponding thermocouples exceed a preset upper limit temperature. Cooling operation is performed by supplying a cooling medium and closing each cooling valve when the indicated temperature of the thermocouple drops to a preset cooling temperature. It is formed so as to end.
[0016]
Although the environmental temperature at the pipe installation location and the upper limit temperature and cooling temperature of the pipe temperature measuring unit vary depending on the concentration of ozone flowing in the pipe, it is usually preferable to set the environmental temperature and the upper limit temperature to 40 ° C. If the temperature is lower than this, when the pipe is installed outdoors, it may rise to the upper limit temperature in summer, and if it is set higher than this, the temperature rise due to decomposition of ozone will be detected quickly. It becomes difficult.
[0017]
On the other hand, the cooling temperature may be equal to or lower than the temperature at which the decomposition reaction of ozone proceeding in the pipe can be stopped. Usually, a sufficient effect can be obtained even at about 20 ° C., but should be set to 0 ° C. or lower. Thus, ozone decomposition can be stopped more reliably. However, if the temperature is set to 0 ° C. or lower, air or water cannot be used as a cooling medium and the cost increases. Therefore, the cooling temperature should be set in consideration of ozone concentration, ozone supply amount, and the like. At this time, if a low temperature adsorption ozone concentrator is installed as ozone supply equipment, a low temperature refrigerant used for cooling the adsorption cylinder of the device, such as liquefied nitrogen, can be used. Even if you want to cool down the pipe when decomposition occurs to a low temperature of 0 ° C or less in a short time, there is no need to prepare a new cryogenic cooling medium, and effective cooling is possible while suppressing an increase in equipment costs. It can be carried out.
[0018]
In the cooling operation, the supply of the cooling medium may be continued and maintained at an appropriate time after the pipe temperature reaches the cooling temperature, but if the cooling temperature is set appropriately, Even when the supply of the cooling medium is terminated when the cooling temperature is reached, the decomposition of ozone can be stopped reliably.
[0019]
In this way, the flow direction, pressure, and flow velocity of ozone flowing in the piping change, that is, bent parts such as elbows, installation parts of various valves such as on-off valves, control valves, and backflow prevention valves, flow meters, Easily detect the occurrence of ozone decomposition in the pipe by measuring the temperature of the pipe surface at the installation part of various devices such as strainers with a simple temperature measuring means such as a thermocouple and monitoring the measured temperature. It is possible to identify the location where the decomposition occurs.
[0020]
In addition, it is possible to detect the decomposition of ozone by providing temperature measurement means at appropriate intervals in the entire pipe, but since a large number of temperature measurement means are required, implementation on an industrial scale is not realistic. Absent. Therefore, as described above, by providing temperature measuring means only at locations where ozone decomposition is likely to occur due to changes in gas flow direction, pressure, and flow velocity, ozone decomposition can be minimized with a minimum number of temperature measuring means installed. Can be detected at low cost. In the normal piping configuration, the pressure gauge 18 hardly changes the gas flow state, so the temperature measuring means in this part can be omitted. A cooling means may be provided.
[0021]
Furthermore, by detecting the decomposition of ozone as described above, it is possible to predict a decrease in the ozone concentration supplied to the ozone consumer. And the operation can be temporarily stopped, and an unexpected situation can be avoided and the predetermined ozone treatment can be reliably performed.
[0022]
In addition, since it is possible to reliably know the part of the ozone supply pipe where decomposition occurs, ozone can be controlled by changing the piping configuration where ozone is frequently decomposed or installing bypass pipes to cope with the occurrence of decomposition. Measures can be taken to ensure a stable supply.
[0023]
In addition, by providing the cooling means 31, 32, 33, 34 in each temperature measurement part, when the thermocouples 21, 22, 23, 24 detect an increase in piping temperature due to ozone decomposition, Ozone decomposition can be stopped by quickly cooling the piping portion.
[0024]
For example, FIG. 2 shows that an ozone concentration meter is provided before and after an elbow provided in the middle of a pipe to measure the inlet concentration and the outlet concentration of ozone passing through the elbow, and a thermocouple is used as a temperature measuring means, and cooling in the cooling means. The results of measuring the change in ozone concentration before and after the decomposition of ozone and the change in pipe temperature using cold water as a medium are shown.
[0025]
As is apparent from FIG. 2, simultaneously with the occurrence of ozone decomposition, the ozone outlet concentration decreases with respect to the inlet concentration and the piping temperature increases. Then, when the thermocouple detects that the pipe temperature has risen to the preset upper limit temperature and operates the cooling means to cool the pipe by supplying cold water into the jacket covering the elbow, the pipe temperature decreases. It can be seen that the ozone outlet concentration increases, that is, the decomposition of ozone generated at the elbow part is suppressed and the decomposition reaction finally stops.
[0026]
Therefore, even if ozone decomposition occurs in the piping, the temperature measuring means can detect the temperature rise and operate the cooling means, so that the normal state can be restored in a short time. The decrease in ozone concentration is negligible, and it does not have a great effect on the ozone treatment, and the operation can be continued in a stable state.
[0027]
Furthermore, the packing and the like are hardly deteriorated due to the heat generated by the decomposition of ozone, so the maintenance cost can be reduced, and the ozone generated by the ozone generator can be used effectively. The ozone yield is not lowered, and the production efficiency in the ozone generation facility and the consumption facility can be improved as a whole.
[0028]
In this embodiment, the temperature rise due to the decomposition of ozone is detected by measuring the temperature of the pipe, but the temperature of ozone flowing in the pipe may be directly measured.
[0029]
【The invention's effect】
As described above, according to the present invention, it is possible to quickly detect the decomposition of ozone flowing in the pipe, and therefore it is possible to quickly cope with a decrease in ozone concentration at the ozone supply destination. In addition, since the portion where ozone decomposition has occurred can be reliably identified, measures such as improvement of piping can be easily performed.
[0030]
Furthermore, since the decomposition of ozone can be stopped by cooling the location where ozone decomposition occurred by the cooling means, the decrease in the concentration of ozone supplied to the ozone consumer can be temporarily reduced. Can minimize the adverse effects of.
[0031]
In particular, an increase in equipment cost can be suppressed by providing temperature measuring means and cooling means in a portion where ozone decomposition is likely to occur.
[Brief description of the drawings]
FIG. 1 is a system diagram of a main part of an ozone supply pipe showing an embodiment of the present invention.
FIG. 2 is a diagram showing the results of measuring changes in ozone concentration before and after ozone decomposition in a pipe and changes in pipe temperature.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Inlet side piping, 12 ... Flowmeter, 13 ... Outlet side piping, 14 ... Inflow piping, 15 ... Outflow piping, 16, 17 ... Elbow, 18 ... Pressure gauge, 19 ... Valve, 21, 22, 23, 24 ... Thermocouple, 21a, 22a, 23a, 24a ... measuring point, 31, 32, 33, 34 ... cooling means, 31a, 32a, 33a, 34a ... jacket, 31b, 32b, 33b, 34b ... cold heat source, 31c, 32c, 33c, 34c ... cooling valve, 31d, 32d, 33d, 34d ... controller

Claims (3)

Measure the temperature of the bent part, valve part, flow meter part, etc. in the ozone supply pipe, the part where the flow direction, pressure, and flow rate of ozone-containing gas flowing in the pipe changes or the vicinity of the downstream side. A method for supplying ozone, comprising detecting decomposition of ozone by rising. The entire piping for supplying ozone is maintained at a temperature that does not exceed a predetermined temperature, and the flow direction, pressure, and flow velocity of the ozone-containing gas flowing in the piping, bends, valves, flowmeters, etc. A method of supplying ozone, comprising: measuring a temperature of a changing portion or a vicinity of the downstream side thereof, and cooling the temperature rising portion when the measured temperature exceeds the predetermined temperature. A temperature measuring means is provided in a bent portion, a valve portion, a flow meter portion, etc. in the piping for supplying ozone, in addition to a portion where the flow direction, pressure, and flow velocity of the ozone-containing gas flowing in the piping changes or in the vicinity of the downstream side, An ozone supply device comprising a cooling means for cooling a portion where the temperature measuring means is installed.

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