JPH0124607Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an apparatus for performing hydraulic pressure tests on pressure vessels, heat exchangers, and the like.

FIG. 1 shows a conventional water pressure testing apparatus for testing boilers for thermal power generation.

The water pressure test water 2 stored in the tank 1 is transferred to the boiler main body inlet valve 7 by piping 3 and water pump 4.
Water supply valve 5 with outlet valve 10, deaerator inlet valve 8, outlet valve 11, reheater inlet valve 9, and outlet valve 12 open.
a, the boiler main body 1 via the water supply pipe 6 and the water supply valve 5b
3. Fill the deaerator 14 and reheater 15 with water pressure test water 2 until they are full. When the water is full, close the outlet valves 10, 11, 12 of the boiler main body 13, deaerator 14, and reheater 15, and close the bypass pipe 1.
6. Increase the pressure to the specified pressure using the pressurizing pump 18 via the bypass valves 17a and 17b.

At this time, it is widely known that the presence of dissolved oxygen in the hydraulic test water 2 has a great negative effect on the corrosion of metals, and the following method is generally used as a measure to prevent metal corrosion.

(1) A method in which water pressure test water is deoxidized by heating before use.

(2) A method in which water pressure test water is deoxidized by aeration with an inert gas such as nitrogen before use.

(3) A method in which water pressure test water is deoxidized beforehand using chemicals such as sodium sulfite or hydrazine.

(4) A method in which an anticorrosive agent is added to the hydraulic test water in advance.

(5) A method in which the hydraulic test water containing dissolved oxygen is used as is, but corrosion is prevented by shortening the hydraulic test time.

However, the above method has the following drawbacks.

(1) The thermal deoxidation method uses high-temperature, high-pressure water to deoxidize, so the equipment must be designed to withstand pressure and become larger. Additionally, high-temperature, high-pressure water generation equipment is required.

(2) The deoxygenation method using inert gas aeration requires a large amount of high-purity aeration gas with low oxygen content, which increases running costs.

(3) The method of deoxidizing using chemicals requires a large amount of chemicals unless either method (1) or (2) above is used in combination.

In addition, running costs increase because waste liquid treatment is required when discharging the water pressure test water at the end of the water pressure test.

(4) The method of using an anticorrosive agent, like the method (3) above, requires a large amount of chemicals and also requires waste liquid treatment, which increases running costs.

(5) Methods that shorten the water pressure time can suppress metal corrosion to some extent, but corrosion cannot be avoided.

The present invention eliminates these drawbacks, and uses a water pressure test device consisting of a tank for storing water, and a water tension pump and pressure pump for supplying and pressurizing the water in the tank into the test subject. It is characterized by comprising an activated carbon packed tower interposed between a water pump and a test object, and an injection device for injecting hydrazine provided in communication with the activated carbon packed tower, and its purpose is to The present invention provides a water pressure testing device that can effectively remove dissolved oxygen from water used for a water pressure test and supply the dissolved oxygen to a test object to perform a water pressure test.

Generally, dissolved oxygen and hydrazine in water are at 200℃
The reaction begins rapidly under the above temperature conditions, but it is said that the reaction hardly progresses near room temperature. The reaction between dissolved oxygen and hydrazine is shown in equation (1).

N ₂ H ₄ +O ₂ →2H ₂ O+N ₂ ↑ ...Equation (1) However, the present inventors rapidly achieved the reaction of Equation (1) above by bringing dissolved oxygen in water and hydrazine into contact on activated carbon at room temperature. I found that this occurs.

Although this is not certain theoretically, hydrazine and dissolved oxygen in water are adsorbed by activated carbon, and hydrazine and dissolved oxygen are concentrated on the adsorbent surface (activated carbon), resulting in a high concentration and promoting the reaction of equation (1). It is estimated that the

Therefore, in this invention, hydrazine is added to the water to be treated in a container that blocks contact between air and the water to be treated at around room temperature, or in a container that blocks air from entering with an inert gas such as nitrogen or water vapor. In addition, hydrazine and dissolved oxygen are decomposed into water and nitrogen gas by contact with activated carbon in the activated carbon-filled chamber, which effectively removes dissolved oxygen contained in the water to be treated and removes the water under test. Water pressure tests can be performed without corroding.

The present invention will be described below with reference to an embodiment shown in FIG. 2, but since the structures and functions of the components designated by the same reference numerals as in FIG. 1 are the same, their explanation will be omitted.

Reference numeral 27 denotes a bypass pipe line that is arranged in parallel with the water supply pipe 6 and bypasses the water supply valve 5b, and includes the valves 25a,
Activated carbon packed towers 24 are interposed which are opened and closed at the front and rear by means of 25b.

20 is a container containing the hydrazine solution 19, and is connected to the pipe 2 through an injection pump 21 and a valve 22.
3, the pipe line 2 on the inlet side of the activated carbon packed tower 24
7, and these dissolver 20, injection pump 21, and valve 22 constitute a hydrazine injection device.

Note that 28 is a pipe attached to the activated carbon packed tower 24, and 29 is a valve for exhausting gas generated within the activated carbon packed tower 24.

Now, in a hydraulic test in which corrosion is not an issue, the test is carried out by supplying the hydraulic test water 2 through the water supply valve 5b, but the hydraulic test using the activated carbon packed tower 24 is carried out as follows.

The water pressure test water 2 containing dissolved oxygen stored in the tank 1 passes through the pipe 3 to the water supply valve 5a, the water supply pipe 6, and the valve 2.
The water is sent to the activated carbon packed tower 24 installed in the bypass pipe 27 via the water tension pump 4 via the water pump 5a. On the other hand, the hydrazine solution 19 is also injected by the injection pump 21 through the valve 22 and the hydrazine injection pipe 23 into the water pressure test water 2 being fed on the upstream side of the activated carbon packed tower 24 .

At this time, the dissolved oxygen in the hydraulic test water 2 comes into contact with the hydrazine solution in the activated carbon 26 in the activated carbon packed tower 24, and undergoes a chemical reaction as shown in the following equation, and the dissolved oxygen decomposes into water and nitrogen gas. removed.

N ₂ H ₄ +O ₂ →2H ₂ O+N ₂ ↑ The water pressure test water from which dissolved oxygen has been removed in the activated carbon packed tower 24 is sent to the boiler main body 13, deaerator 14, and reheater 15 via the valve 25b as in the conventional case. etc. Fill with water. Note that the water pressure test water from which dissolved oxygen has been removed contains dissolved oxygen again when it comes into contact with the air in the system, so the boiler main outlet valve 10, deaerator outlet valve 11, reheater outlet valve 12, etc. The water is discharged to the outside of the system through the water pressure test water 2 until the dissolved oxygen concentration in the water pressure test water 2 decreases. This simultaneously cleans any dirt that may have adhered to the system.

If the dissolved oxygen concentration in the water pressure test water 2 discharged outside the system decreases, the boiler main outlet valve 10,
The deaerator outlet valve 11 and the reheater outlet valve 12 are closed, the water pump 4 is stopped, and the valve 25b is closed.

Next, the water pressure test water 2 is transferred to the bypass inlet valve 17b, the bypass outlet valve 17b, the bypass pipe 16, and the valve 25a.
The water is sent to the activated carbon packed tower 24 via the pressurizing pump 18.

On the other hand, the hydrazine solution 19 is also injected into the hydraulic test water 2 being fed to the upstream side of the activated carbon packed tower 24 through the valve 22 and pipe 23 by the injection pump 21, and in the activated carbon 26 in the activated carbon packed tower 24. After the dissolved oxygen in the water pressure test water 2 is removed by reacting with hydrazine as described above, the pressure is increased by the pressure pump 18 via the valve 25b and a water pressure test is performed. Note that N ₂ gas generated by the reaction of hydrazine and dissolved oxygen in the activated carbon 26 in the activated carbon packed tower 24 is removed to the outside of the system via a pipe 28 and a valve 29 .

In this way, the boiler body 13 which is the test object
When the water pressure test water 2 is supplied and pressurized, the water pressure test water 2 does not contain dissolved oxygen and corrosion of the test object can be prevented.

Figure 3 shows the dissolved oxygen removal test in water pressure test water according to the present invention at a concentration of 1 equivalent of hydrazine (8 ppm), space velocity, and SV = 20.
Figure 4 shows the results of the removal test in relation to the hydrazine concentration and the SV value. As is clear from Figure 3, when water test water containing 8 ppm dissolved oxygen and 1 equivalent of hydrazine is passed through the activated carbon packed tower at SV = 20, the dissolved oxygen in the test water at the outlet of the activated carbon packed tower is reduced to 0.003 ppm. The amount of dissolved oxygen removed water collected was more than 1000 liters per liter of coconut shell activated carbon.

Also, from Figure 4, dissolved oxygen in the water pressure test water8
Adding 1 equivalent of hydrazine to hydraulic test water containing ppm can reduce dissolved oxygen to 0.003 ppm up to SV = 20, adding 2 equivalents (16 ppm) up to SV = 30, and adding 3 equivalents (24 ppm) to SV = up to 40,
It can be seen that by adding 5 equivalents, dissolved oxygen can be reduced to 0.003 ppm up to SV=60.

As described above, according to the present invention, dissolved oxygen in the water pressure test water can be reduced to 0.003 ppm, so corrosion due to dissolved oxygen in the water pressure test water can be sufficiently prevented.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a conventional water pressure testing device, Fig. 2 is an explanatory diagram of an apparatus showing an embodiment of the present invention, Fig. 3 is a diagram showing the relationship between water flow rate and dissolved oxygen concentration, and Fig. 4 is an explanatory diagram of a conventional water pressure testing device.
The figure is a diagram showing the relationship between space velocity and dissolved oxygen concentration. 1: Tank, 2: Water pressure test water, 4: Water pump, 13: Boiler body, 14: Deaerator, 15: Reheater, 18: Pressure pump, 19: Hydrazine solution, 21: Injection pump, 22 : Valve, 24: Activated carbon packed tower.

Claims (1)

[Scope of utility model registration request] In a hydraulic test device consisting of a tank that stores water, a water pump and a pressure pump that supply and pressurize the water in the tank into the test object, activated carbon is interposed between the water pump and the test object. a packed tower;
A hydraulic testing device characterized by comprising an injection device for injecting hydrazine, which is provided in communication with the activated carbon packed column.