JPS58174285A - Method and device for deoxidizing feed water - Google Patents

Abstract

PURPOSE:To prevent the corrosion of a feed water system and to deoxidize feed water quickly, by mixing the hydrogen which is supplied through a reducing valve from a pressure vessel contg. a hydrogen occluding material with the feed water, and supplying the mixture to a vessel containing a catalytic resin thereby deoxidizing the feed water. CONSTITUTION:Heated fluid such as steam, hot water or the like is supplied through a pipeline 39 and a flow rate controlling valve 39a to a mixer 44, and cooling fluid such as cold water is supplied through a pipeline 40 and a flow rate controlling valve 40a to the mixer 44,where both are mixed to the fluid of the controlled temp. The temp. thereof is checked with a thermometer 43, whereafter the mixture is supplied through a flow rate controlling valve 43 and a pipeline 41 into a heat transmitting coil 5. The temp. of the hydrogen occluding material 4 in a hydrogen storage vessel 1 is controlled to a suitable value, and is discharged through a pipeline 45 and a valve 46. The heated fluid may be supplied independently through a pipeline 41 in the stage of releasing the gaseous H2 occluded therein and the cooling fluid may be flowed independently through the pipeline 41 in the hydrogen occluding stage.

Description

[Detailed description of the invention] This invention deoxidizes water supply. Regarding the method and its equipment "'1 do.

In recent years, there has been a strong demand for the oxygen content in the feed water of boilers, particularly in high temperature and high pressure boilers, to be in the PPb class. On the other hand, low pressure lo'Y! There is also a strong demand for reducing the oxygen content in G-class products with low operating pressures. This is because the means for removing impurities in the water supply has been improved, and the problem of oxygen corrosion has appeared because there is less scale than in the past, which had a large amount of scale and a layer of scale adhesion that prevented oxygen corrosion. be.

Conventionally, oxygen contained in water supply has been removed using chemicals. Sodium sulfite, which is used as one of the chemicals, decomposes more easily at higher pressures and temperatures, which generates SO2 gas, which is oxidized in the superheater and becomes SO2.
3, and as the steam condenses in the low pressure stage of the turbine, H2SO
4, causing corrosion of the members of the low-pressure stage and lowering the pH value of condensate, which is a cause of system corrosion.

Furthermore, hydrazine (N2H4) has been widely used as a preferred oxygen scavenger since it reacts with oxygen to form water and nitrogen as shown in the following formula.

N2H4+ 02 ” 2H20+ N2
(1) However, N2H4 is toxic to people with specific constitutions, so caution is required.

In addition, this hydrazine must be supplied in a slightly larger amount than the calculated theoretical value in order to reduce the amount of oxygen contained in the water supply, and the excess hydrazine either evaporates as it is, or evaporates as shown in equation (2). decomposes into ammonia and nitrogen.

3N2H,→4NH3+N2... (2) The ammonia generated here enters the condensate and makes the PH value of the condensate high, and if there is too much ammonia, it will corrode copper-based metals. There is a problem. In any case, chemical deoxidation means strongly require proper control of the supply amount, and still cause the problem of member corrosion in the water supply system and condensate system.

The object of the present invention is to propose a new deoxidation method and device for supplying low-pressure hydrogen gas into water supply to easily and efficiently remove oxygen from the water supply.

However, even if hydrogen gas is simply supplied into the water supply to remove oxygen from the water supply, it will not dissolve sufficiently into the water supply, and will not react sufficiently with the oxygen in the water, resulting in a large amount of hydrogen gas being added. The handling of high-pressure hydrogen cylinders requires the supervision of a responsible person, and handling heavy cylinders is not easy.

This invention makes it possible to supply a stable HPS from a low-pressure vessel, which mixes well with the feed water to dissolve it, and in addition passes the feed water through a bed of a suitable catalytic resin to provide sufficient catalysis due to its catalytic action. The present invention is characterized in that it proposes a method and an apparatus for continuously performing operations for removing 0 points.

An apparatus according to the present invention will be explained below with reference to the drawings. If you try to supply hydrogen gas from a hydrogen cylinder, the high-pressure hydrogen cylinder has an internal pressure of 150 yen Ig, and the cylinder must have a thick wall to withstand that pressure.In addition, each cylinder is heavy, and it is a high-pressure dangerous substance. It is more difficult to handle than it is. Furthermore, in order to convert liquid hydrogen from -253°C to gas at room temperature and low pressure, there are many attached devices, which are difficult to handle.

The inventors focused on the storage capacity of recently developed hydrogen storage alloys and created an invention using this.

FIG. 1 is a diagram showing a piping system for connecting equipment according to the embodiment of the present invention. Reference numeral 1 is a hydrogen storage container. FIG. 2 is a vertical sectional view of the container, which can withstand an internal pressure of 20 to 30 yen Ig. Materials that make the container lighter, such as AI or A1 alloy, can be used. A diffuser plate 3 is positioned between seven flanges of the trunk body 1a and a flange of a hemispherical lower lid 1b forming a bottom pressure chamber 2. The diffusion plate 3 is a porous plate (porous ceramic material) that prevents the hydrogen storage material (powder, small lump form) 4 housed in the body from leaking into the bottom pressure chamber 2 and allows hydrogen gas to pass through.

made of sintered metal plate or metal plate with small holes). In addition, the diffuser plate has a wire mesh on its outer surface and is heat resistant (maximum 120
It may also be a canvas woven from synthetic fibers, etc. that can withstand temperatures of A substantially hemispherical upper Mlc is connected to the upper flange of the barrel by seven flange. The flange surface uses airtight packing and airtight material to create a structure that prevents hydrogen leakage. If necessary, the periphery of the flange connection portion may be sealed and welded. Further, a heat transfer coil 5 is located inside the shell la, and hot water, steam, cooling water, or cooling gas is passed through the heat transfer coil to adjust the temperature inside the shell. Further, the temperature is measured by the temperature transmitter 6, and the temperature signal is sent to the control box 12 and can be displayed on the instrument. The hydrogen storage material in the hydrogen storage container 1 is supplied with a pressure reducing valve 8 from a hydrogen source such as a hydrogen cylinder 7. Valve 9 connected to the lower lid
Hydrogen is supplied and stored through the pressure chamber 2 and the diffusion plate 3. Although only one hydrogen storage container l is shown in Figure 1, two or more hydrogen storage containers are installed in parallel (only the outlet valves 11b and 110 of the hydrogen storage container are shown), and a hydrogen gas supply main pipe (hereinafter simply referred to as the hydrogen main pipe) is provided. ) 10, and the hydrogen storage container outlet valves 11a, 11b, llc are switched by memory and a command signal from the control box 12 that outputs a command signal, or by manual operation, to supply hydrogen gas to the deodorizing container 34. Can be done continuously. The pressure inside the hydrogen storage container 1 is sent to the control box 12 as a pressure signal from a pressure gauge 13 connected to the upper lid IC.

The hydrogen gas at a pressure of 20 to 305 g in the hydrogen storage container 1 is reduced in pressure by the pressure reducing valve 14 from the outlet valve 11a to the main hydrogen pipe 10, and becomes hydrogen gas at a hydrogen release pressure of 5 to 85 g. The adjustment can be done manually by visually observing the pressure transmitters 15a, 15b installed in the main hydrogen pipe 10 before and after the pressure reducing valve 14, or by commands from the control box 12 that receives signals from these pressure transmitters 15a, 15b. Controlled by a signal. The reduced pressure hydrogen gas passes through the hydrogen gas flow meter 16 and the stop valve 25 and is supplied to the hydrogen feed water mixer 17 .

An example of the hydrogen supply water mixer (hereinafter simply referred to as mixer) 17 has a structure whose cross section is shown in FIG.

Water supply W is water softener 18. Soft water tank19. Water pump 2
0 via a water supply pipe line 21 and a water supply flow rate control valve 22. The water is supplied to the mixer 17 via the water supply flow meter 23. In addition,
The soft water tank or water supply pipe 21 is provided with an 02 meter 24 for measuring 02 in the supplied water, and the 02 content in the supplied water is displayed on the meter and sent as a signal to the control box 12.

The structure of the mixer 17 will be explained with reference to FIGS. 3 and 4. The mixer 17 includes a venturi part 17a and a baffle mixing part 17.
It consists of b. In order to increase the amount of gas dissolved in water, it is preferable that the water temperature for HI gas is 50° C. or lower.

Figure 5 shows the volume of H2 dissolved in water/ml at a pressure of 760 mmHg, O'C, a value a (Bunsen absorption coefficient) XIO'' converted to 760 mmHg, on the vertical axis.
It is a diagram showing temperature on the horizontal axis. For pressure, He
According to Nry's law, ``When the temperature is constant, the solubility of a gas in a given amount of liquid is directly proportional to the partial pressure of that gas.'' The higher the pressure, the better the solubility of duck. Therefore, the H of the container
20~30'J depending on the storage material capacity, wall thickness, price, etc.
It is preferable to select a container pressure of 5 g and reduce the pressure to 5 to 8 Vg for use. H, f7, which was depressurized to this 5~aVg
The gas is supplied from the main hydrogen pipe 10 via the stop valve 25 to the air chamber 26 of the venturi part 17a, and is supplied into the water supply from the plurality of nozzles 28 provided at the throat part 27 of the venturi, forming Jl and fine bubbles. On the other hand, the water supply enters the venturi part 17a from the pipe 21 and enters the throat part 27.
And H! Baffle mixing section 17
The flow under the resistance of the baffle 29 becomes turbulent and mixes well with the gas, and the main flow control valve 31. Via the water supply spray supply device 32, a plurality of nozzles 32a provided in the water supply spray supply device 32 are ejected into the supply water in the deoxidizing container 34 having the catalytic resin layer 33 to ensure a good and sufficient amount of 02 and H2 in the water. It contacts, passes through the catalyst layer, reacts with 02 due to its catalytic action, becomes water (H2O), and is deoxidized. This deoxygenated feed water is supplied to the flow control valve 35. The water is supplied from a pipe 38 via a water pump 36 and a water flow meter 37 to boilers and other devices that require water supply.

Next, the hydrogen storage material accommodated in the hydrogen storage container 1 will be explained. The recently developed TiMn alloy is an extremely preferable material in terms of storage capacity and handling. The behavior of hydrogen during hydrogen storage is: △H is the calorific value of 7.0K01LI
/H21! It is +101.

``Mrll, It takes the form of a 5H2,+4 solid solution, and when it releases hydrogen, it becomes fine powder particles, and when it absorbs hydrogen, it becomes granules.

It has the property of forming small lumps. H! In experiments, no decrease in the storage capacity was observed even after several thousand times (6000 times) of storage and release of gas.

The properties of the TiMn alloy as the hydrogen storage material are as follows.

(a) Hydrogen storage capacity: 180 to 220 c per gram of alloy
1.134 to 1.386 C per cice (b) Hydrogen release rate Average 88% (c) Hydrogen release pressure 5 to 8 atm (20 to 40°C) Figure 6 shows the temperature of TiMn and TiFe-H and hydrogen 1 ．．
5H is a diagram showing the relationship with discharge pressure.

By using such a hydrogen storage material, it is extremely easy to supply hydrogen at room temperature, the amount of hydrogen stored is relatively large, and it is possible to release hydrogen at an almost constant pressure at room temperature. The feed water deoxidizer according to the present invention has advantages such as being relatively inexpensive.

The first for the fluid flowing into the heat transfer coil 5 in the hydrogen storage container 1.
This will be explained using figures. Steam or hot water.

Heated fluid such as hot gas is passed through line 39. Flow control valve 39
A cooling fluid such as cold water is supplied to the mixer 44 via the pipe 40.a. The fluid is supplied to the mixer 44 via the flow rate control valve 40a and mixed to obtain a fluid at a controlled temperature.
After confirming the temperature, it is supplied to the heat transfer coil 5 from the conduit 41 via the flow rate control valve 42. The temperature of the hydrogen storage material 4 in the hydrogen storage container 1 is adjusted to an appropriate temperature, and the hydrogen storage material 4 is discharged via a pipe 45 and a valve 46. The heated fluid absorbs H
When the two gases are released, they are supplied individually through the pipe 41, and when the hydrogen storage material is used, the cooling fluid may be supplied separately through the pipe 41 and passed through the mixer without mixing.

The reason why the diffusion plate 3 is provided in the hydrogen storage container is that since the hydrogen storage material before hydrogen storage is in the form of fine powder, the hydrogen gas supplied from the hydrogen cylinder 7 causes the fine powder in the container to form a fluidized bed. The area of contact with the H2 gas is large and uniformly contacts the hydrogen gas, which has the effect of significantly shortening the storage time.

Next, deoxidation, which is the reaction between the bow and 02 in the deoxidation container 34, will be explained. This device has a structure similar to a commonly used container using ion exchange resin. An ion exchange resin layer 33 is located on a porous plate 34a (the resin layer is a plate) inside the container, and an ion exchange resin supply nozzle 50 and a stop valve 51 are provided on the upper end plate.

A water supply discharge nozzle 52 and a main conduit 54 for deoxygenated water supply connected to the water supply discharge nozzle 52 are provided on the lower end plate. A conduit 55 branching from the main conduit 54 is provided with stop valves 53a, 53b and a backwash conduit 56 connected to the conduit 55 between these two stop valves.

The ion exchange resin used is a catalyst resin mainly used for deoxidizing, and is a gel type strongly basic type I anion exchange resin. This is because a reaction occurs on the surface of the catalytic resin containing palladium, and it has a special effect on deoxidizing the aqueous solution.

- In the example, the product name is Lepachitsu) O (1! 1045).The stable temperature for use is below loo'c.

In tests and experiments using this device to supply hydrogen-containing feed water, it has been determined that when the hydrogen feed phase becomes slightly less than its stoichiometric amount, the amount of residual oxygen increases.

No. 71, 1 shows the experimental results. The amount of residual oxygen when H2 is supplied in an amount larger than the chemical theoretical amount is shown in the diagram in the area of code A, and when H2 is supplied slightly less than the chemical theoretical amount, the residual oxygen amount is shown in the diagram with the sign A region. It becomes a diagram of area D, and if it is further reduced, it becomes a diagram of areas C and D. This contains slightly more H than the stoichiometric amount? : When supplied, the residual 0 delay rapidly decreased to a value in the D range, confirming its rapid effect. Also, the speed of water supply passing through the catalyst resin layer nv/h @1ooj water/h/resin layer i
) Of course, the slower the time, the more effective the deoxidation is, as shown in Figure 8.

FIG. 9 shows a control system according to the present invention, and the symbols of equipment members correspond to the symbols in FIG. 1. As mentioned above, in order to properly remove O2 from water, it is necessary to supply H2 gas in an amount greater than the stoichiometric amount of H2 corresponding to the amount of O2. Therefore, the amount of 02 in the supplied water is determined by the flow rate signal of the water supply flowmeter 23 and the 02) that measures the OA in the water supply.
24 and the 02 quantity signal are sent to the control box 12 and obtained by multiplying them. The amount of H2 required for this is hydrogen gas flow meter 1
6 and the pressure signal of the pressure gauge 15b are transmitted to the control box 12.
is sent to and calculated. The pressure of the head gas sent to the mixer 17 is determined by a signal from the pressure gauge 13 that measures the pressure inside the hydrogen storage container 1 and a signal from the pressure transmitters 15a and 15b, which is sent to the control box 12 to control the pressure reducing valve 14. It is adjusted by

In addition, by switching the exit valves 11a, llb, and lla, H
The delivery of the two gases can be continuous, with H!
It is possible to perform occlusion operations. As shown in the diagram in FIG. 6, the H, ff gas pressure in the hydrogen storage container 1 is determined by the temperature of the temperature transmitter 6 and the amount of HI gas sent out. The temperature signal from the heat transfer coil is sent to the control box 12, and the temperature of the fluid flowing through the heat transfer coil is adjusted and controlled by the flow rate control valves 39a and 40a based on the signal from the hygrometer 43. Control is performed such that the amount of gas generated is determined and the result is displayed on the pressure gauge 13.

The amount of water supplied to the mixer 17 is controlled by the water supply flow rate control valve 2z.

The amount of water to be fed is adjusted by sending a signal of the remaining 02 amount from the 02 meter 57 and a signal from the water flow meter 37 to the control box 12 and controlling the valve 35 and/or the main flow control valve 31.

Further, a load signal (not shown) of the device to which the deoxygenated feed water is supplied can be input into the control box 12 and added as a factor for controlling the device.

By carrying out this invention, an appropriate amount of H, tt gas is supplied to the deoxidizing container 34 together with the water supply, and the catalyst resin layer 33
O, so there is no corrosion of the boiler water supply system or turbine plant, and the H2 gas supply equipment is
OYet G class low pressure can be used, H
! The storage and release of gas can be easily controlled, the storage metal material can be used repeatedly, and furthermore, the deoxidizing reaction can be achieved in a short period of time, eliminating the need for deoxidizing agents such as hydrazine.

[Brief explanation of the drawing]

FIG. 1 is a drawing showing the piping system of the device according to the present invention.
Figure 2 is a cross-sectional view of the hydrogen storage container, Figure 3 is a vertical cross-sectional view of the mixer, Figure 4 is a cross-sectional view taken along I-■ in Figure 3, and Figure 5 is the water temperature regarding the solubility of H gas in water. Figure 6 shows the relationship between TiMn 1.5H and Bunsen absorption coefficient.
A diagram showing the relationship between humidity and hydrogen release pressure for Ti1Pθ-H alloy and Ti1Pθ-H alloy. ,
IIs diagram showing the change in the amount of residual oxygen in C and D) with time as the horizontal axis, Figure 8 is a diagram showing the relationship between the flow rate in the deoxidizing container and the residual oxygen in the treated water, and Figure 9 is 1
FIG. 2 is a control system diagram of the device shown in the figure. 1...Hydrogen storage containers 11a, llb, 1lc--Outlet valve 12...Control box 14...Pressure reducing valve 17...Mixer 2o... ...Water pump 31...Main flow control valve 34...Oxygen removal container 36...Water pump

Claims (1)

[Claims] 1. A water supply characterized in that hydrogen supplied from a pressure vessel containing a hydrogen storage material via a pressure reducing valve is mixed with water supply and supplied to a container containing a catalyst resin for deoxidation. How to remove oxygen. 2. The method for deoxidizing feed water according to claim 1, wherein the hydrogen storage material is a TiMn-based alloy, and the catalyst resin is a coarse anion exchange resin to which palladium is added. 3. The content of oxygen in the supplied water is measured before it is mixed with hydrogen, and hydrogen is supplied in an amount greater than the stoichiometric amount for reacting with the oxygen to form water. The method for deoxidizing feed water according to paragraph 2. 4. A hydrogen storage container containing a hydrogen storage material and a built-in heat transfer coil that can switch or mix the heating fluid and the cooling fluid to supply a dry supply, a pressure reducing valve, a hydrogen gas flow meter, and a hydrogen water supply. The hydrogen-containing water supply pipe connects the mixer, the main flow control valve, and the water spray supply device located in the deoxidizing container with a pipe, and the water supply tank, the water supply pump, the water supply flow rate control valve, and the water supply flow meter are connected to the water supply pipe. A water supply water deoxidizer comprising a water supply pipe connected by a pipe having a thermometer, a main flow control valve, and a deoxygenation container incorporating the water supply spray supply device and having a catalytic resin layer. . 5. A hydrogen supply water mixer is connected to a part of a venturi that receives water supply, a hydrogen gas chamber that supplies hydrogen gas from a nozzle provided in the throat of this venturi part to the throat, and a part of this venturi, and 5. The feed water deoxidizer according to claim 4, characterized in that the baffle is formed by connecting the baffle-equipped mixing chamber. 6. In the feed water deoxidizer according to claim 4, a signal of a pressure difference before and after a pressure reducing valve that reduces the pressure of hydrogen gas supplied from a hydrogen storage container, and a flow rate signal of a hydrogen gas flow meter; A control box is provided to receive the residual oxygen amount signal of the deoxygenated feed water and the flow rate signal of the water supply flow meter, and to output a command signal, and the outlet valve of the hydrogen storage container, the pressure reducing valve, and the main flow control valve of the feed water mixed with hydrogen are installed. A feedwater deoxidation device characterized in that a feedwater control system is provided for controlling a feedwater flow rate control valve for feedwater before hydrogen mixing and a flow rate control valve for deoxygenated feedwater. 7. The water supply according to claim 6, characterized in that the temperature inside the hydrogen storage container is sent as a temperature signal to a control box, and the temperature-adjusted fluid is supplied to a heat transfer coil provided inside the hydrogen storage container. Oxygen absorber.