JPH041657B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a means for dissolving ferrous sulfate in cooling water, primarily to prevent corrosion of heat exchangers.

[Problems to be solved by conventional technology and invention]

Conventionally, in order to prevent corrosion of copper alloy thin tubes for power plant turbine condensers, chemical plants, and other heat exchangers, a method has been adopted in which ferrous sulfate is injected into cooling water. Conventionally, as a means of mixing ferrous sulfate into cooling water, the amount of ferrous sulfate to be dissolved is measured from the amount of cooling water injected into a heat exchanger, mixed in a dissolution tank, and then thoroughly mixed with a mixer. It was mixed and dissolved before use. Therefore, in order to mix ferrous sulfate into cooling water, it is necessary to measure the amount of water and the weight of ferrous sulfate, which requires time and effort from operating personnel each time.

The present invention was made in view of the problems of the conventional technology, and its purpose is to measure the amount of ferrous sulfate each time without measuring the amount of water in the dissolution tank. By adding any amount of ferrous sulfate to the dissolution tank all at once, a saturated solution of ferrous sulfate is obtained, and from this saturated solution of ferrous sulfate, the cooling water is added. The object of the present invention is to provide a means for continuously obtaining a drug solution of a concentration necessary for injection.

[Means to solve the problem]

In order to achieve the above object, the gist of the present invention is to divide a tank into two upper and lower chambers by a mesh body, provide a drug inlet and a circulating fluid spout in the upper part of the upper chamber,
A circulating liquid discharge pipe is provided at the bottom of the lower chamber to circulate the chemical liquid in the dissolution tank, and a water supply pipe is connected to the chemical liquid discharge pipe separately connected to the bottom of the lower chamber to mix the chemical liquid and water. Concentration control comprising a concentration measuring element for measuring the concentration of the mixed liquid, and adjusting the concentration of the chemical solution by controlling the water supply amount of the water supply pipe based on the concentration measured by the concentration measuring element. There is provided a continuous supply device for a chemical solution comprising a device.

〔Example〕 An embodiment of the present invention will be described based on FIG.

Reference numeral 1 denotes a dissolution tank. The dissolution tank 1 has a drug inlet 2 at the top for introducing ferrous sulfate as a drug, and a mesh body 3 is installed horizontally in the dissolution tank 1. Reference numeral 4 denotes a partition wall that partitions a chemical liquid that is a solution of ferrous sulfate, and 5 represents a thermometer in the chemical liquid section. A circulating fluid discharge pipe 7 connected to the bottom of the dissolving tank 1 is connected to a circulating fluid spout 8 provided at the top of the dissolving tank 1, and a circulating pump 6 is disposed within this circulating fluid discharge pipe. 9 is a float valve, which is a valve that adjusts the amount of water supplied from the water supply tank 17 to the circulating fluid discharge pipe 7 via the water supply pipe 18 in order to keep the amount of chemical solution in the dissolution tank 1 constant. . A chemical liquid discharge pipe 10 separately connected to the bottom of the dissolution tank 1 is connected to a water supply pipe 11 at a connection point 12 . Reference numeral 13 denotes a concentration measuring element that measures the concentration of the chemical solution mixed with water, and sends a concentration signal measured by this element to the concentration control device 14, which controls the variable discharge amount pump 1.
Control the amount of water supplied from 5. 16 is a constant volume discharge pump that controls the discharge amount to a constant value; 19 is a diluted chemical liquid supply pipe; 20 is a concentration sensor; 21, 22, 2
3 is a valve, and 24, 25, 26 are pipes.

Next, the usage status of the continuous chemical supply device according to the present invention will be described together with its operation.

(1) From the start of water supply until the chemical solution concentration reaches a saturated state At this point, valves 22 and 23 are closed, and valve 21 is open.

First, the drug D is inserted into the dissolution tank 1 from the drug inlet 2.
When the drug D is thrown in, the drug D is deposited on the net body 3. Initially, the float valve 9 is open because there is no chemical solution. As a result, the water in the water supply tank 17 is fed to the circulating fluid discharge pipe 7 via the water supply pipe 18, and this water is pumped into the circulating fluid by the circulating pump 6 disposed in the circulating fluid discharge pipe 7. The circulating fluid is sent to the outlet 8 and is injected from the circulating fluid spout 8 onto the medicine D deposited on the net body 3 to create a medicine solution. This drug solution accumulates in the lower part of the mesh body 3, but since it takes time for the drug to dissolve in water, the concentration of the drug solution produced initially is low. The water in the water supply tank 17 is continuously supplied to the circulating fluid discharge pipe 7 via the water supply pipe 18, and this water is sent to the circulating fluid outlet 8 by the circulation pump 6 together with the chemical solution accumulated at the bottom of the net body 3. . Then, this chemical solution is injected from the circulating fluid spout 8 to the drug D in the dissolution tank 1, and the amount of the drug dissolved in the drug solution gradually increases, so that the concentration of the drug solution gradually increases. In this way, the amount of drug dissolved in the drug solution increases, the concentration of the drug solution increases, and the absolute amount of the drug solution increases. As a result, when the amount of chemical solution reaches the closed position of the float valve set at a predetermined position, the float valve 9 is closed and the water supply pipe 1
8, the water supply to the circulating fluid discharge pipe 7 is stopped.

After this, only the chemical solution is discharged from the circulating fluid discharge pipe 7.
through the circulating fluid spout 8 by the circulation pump 6.
The amount of drug D that is injected into the dissolution tank 1 from the circulating fluid outlet 8 and dissolved in the drug solution further increases. As a result, the concentration of the chemical solution eventually reaches a saturated state. The concentration of this chemical solution is determined by the concentration sensor 20.
Detected by. Further, since the concentration of the chemical solution is related to the temperature of the chemical solution, the temperature of the chemical solution is monitored by the thermometer 5.

(2) Discharging and adjusting the concentration of the chemical solution after the concentration of the chemical solution has been saturated Next, the valve 22 is opened, and the chemical solution that has become saturated as described above is taken out from the dissolution tank 1 through the chemical solution discharge pipe 10, and the water supply pipe 11 At the connection point 12 with water, it is mixed with water and diluted to a constant concentration. That is, the concentration of the chemical solution is continuously measured by the concentration measuring element 13 disposed in the diluted chemical solution supply pipe 19, and the measured value is continuously sent to the concentration control device 14, which determines the concentration of the drug solution after dilution. The amount of water supplied from the variable discharge amount pump 15 is controlled so as to keep the amount of water constant. That is, when the measured concentration is high, the amount of water supplied is large, and when the measured concentration is low, the amount of water supplied is small. The chemical solution adjusted to a constant concentration in this manner is delivered in a constant amount by the constant volume discharge pump 16.
The amount of this chemical liquid is controlled to the required amount to be injected into the heat exchanger cooling water, and is injected into the heat exchanger cooling water via pipes 24, 25, or 26. During this time, the circulation pump 6 is still operating, and the chemical solution is injected into the dissolution tank 1 from the circulating fluid spout 8.
Excess drug that cannot be dissolved in the drug solution at the saturation concentration remains on the mesh body 3 and is discharged from the drug solution discharge pipe 10 with the drug solution concentration in a substantially constant saturated state.

Meanwhile, during this time, the amount of chemical solution in the dissolution tank 1 gradually decreases, and when it eventually reaches the open position of the float valve 9, the float valve 9 is opened and the water supply from the water supply pipe 18 to the circulating fluid discharge pipe 7 is resumed. . and,
This water is sent to the circulating fluid spout 8 by the circulating pump 6 together with the chemical solution in the circulating fluid discharge pipe 7.
The circulating fluid is injected into the dissolution tank 1 from the circulating fluid spout 8 .
Although the concentration of the chemical solution at the time it is injected into the dissolution tank 1 is slightly lower than the saturated state, a certain amount of the drug D is dissolved before it reaches the bottom of the dissolution tank 1, so the valve 2
It is possible to ensure that the concentration of the chemical liquid discharged from the chemical liquid discharge pipe 10 via the chemical liquid discharge tube 10 through the chemical liquid discharge pipe 10 is almost saturated. As described above, this chemical solution is diluted to a constant concentration at the connection point 12 and then the constant volume discharge pump 16
A fixed amount is sent out. During this time, dissolution tank 1
The amount of the chemical solution increases, and eventually the closed position of the float valve 9 is reached, the float valve 9 is closed, and the water supply from the water supply pipe 18 to the circulating fluid discharge pipe 7 is stopped. After that, the same operation as above is repeated,
A certain concentration and amount of chemical liquid is injected into the heat exchanger cooling water.

Note that, if necessary, the valve 22 can be opened to discharge the drain in the dissolving tank 1.

〔Effect of the invention〕

As is clear from the above description, the present invention provides a net horizontally in the dissolution tank, deposits powdered chemicals such as ferrous sulfate on the net, and sprays water on top of the net to deposit ferrous sulfate and other powdered chemicals. An aqueous solution is created, this aqueous solution, i.e., a chemical solution, is circulated in a closed circuit to increase its concentration, and the chemical solution that has reached a saturated concentration is taken out of the dissolution tank, diluted by mixing with water, and then injected into the cooling water used in the heat exchanger. This is a continuous chemical supply device that supplies a constant amount of a diluted chemical solution with a concentration suitable for the purpose of use, so it is effective in preventing corrosion of copper alloy thin tubes used in conventional power plant turbine condensers, chemical plants, and other heat exchangers. When injecting a solution of ferrous sulfate into cooling water, the burden placed on plant operating personnel, such as measuring the amount of ferrous sulfate needed, mixing it with the water, and stirring it, has been completely eliminated. be done. Therefore, it is possible to save labor, and the labor that would have been devoted to the above-mentioned work can be diverted to other work, so its industrial utility value is extremely high.

[Brief explanation of drawings]

FIG. 1 shows a system diagram of an embodiment of the present invention. 1... Dissolution tank, 2... Drug inlet, 3... Net, 4... Partition wall, 5... Thermometer, 6... Circulation pump, 7... Circulating fluid discharge pipe, 8... Circulating fluid Spout port, 9...Float valve, 10...Medical solution discharge pipe, 1
DESCRIPTION OF SYMBOLS 1... Water supply pipe, 12... Connection point, 13... Concentration measurement element, 14... Concentration control device, 15... Variable discharge amount pump, 16... Fixed volume discharge pump, 17...
... Water supply tank, 18 ... Water supply pipe, 19 ... Diluted chemical solution supply pipe, 20 ... Concentration sensor, 21, 2
2, 23... valve, 24, 25, 26... pipe line.

Claims (1)

[Claims] 1. Divide the tank into two upper and lower chambers with a mesh, provide a drug inlet and a circulating fluid spout at the top of the upper chamber, and provide a circulating fluid discharge pipe at the bottom of the lower chamber to circulate the chemical solution in the dissolution tank. In addition, a water supply pipe is connected to a chemical liquid discharge pipe separately connected to the bottom of the lower chamber to mix the chemical liquid and water, and a concentration measuring element is provided downstream of the water supply pipe to measure the concentration of the mixed liquid. A continuous supply device for a chemical solution, comprising a concentration control device that adjusts the concentration of the chemical solution by controlling the amount of water supplied through the water supply pipe based on the concentration measured by the element.