JP2007292457A - Steam boiler device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress corrosion of a steam boiler condenser pipe without using any chemical agent. <P>SOLUTION: Feed water stored in a feed tank 3 is supplied to a steam boiler 2 through a supply passage 6, wherein it is made into steam and supplied to a heat exchanger 4 through a steam supply pipe 7. The steam passed through the heat exchanger 4 is partially changed to condensed water during passing in a steam recovery pipe 8, and further condensed by separating steam in a steam trap 9. The resulting condensate is stored in a condensate tank 11 through a condenser pipe 10 and supplied to the feed tank 3 through a connection passage 13. Oxygen and carbon dioxide dissolved in the feed water and the condensate stored in the feed tank 3 and the condensate tank 11, respectively, which corrode the steam boiler 2 or the like, raise in the feed water or condensate with an inert gas from an inert gas feeder 21 and discharged out through exhaust ports 3a and 11a. Therefore, the oxygen concentration and carbon dioxide concentration dissolved in the feed water and the condensate are set small. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a steam boiler device, and more particularly to a steam boiler device that reuses condensate obtained by condensing steam from a steam boiler as supply water for the steam boiler.

  The condensate pipe made mainly of steel pipe for reusing the condensate obtained by condensing steam from the steam boiler as supply water for the steam boiler may be forced to be replaced due to corrosion. It is understood that corrosion of condensate piping is mainly caused by the influence of carbon dioxide and dissolved oxygen in the condensate. Corrosion caused by carbon dioxide is caused by lowering the pH of the condensate by the carbon dioxide produced by thermal decomposition of the feed water containing carbonate ions in the steam boiler, and the piping in contact with the condensate Since it progresses equally to the inner surface portion of the pipe and causes the pipe to become thin, it has a feature that the traveling speed is relatively slow. On the other hand, the corrosion caused by dissolved oxygen has a partially concentrated corrosion action on the lower part where sludge is accumulated, such as the lower part of the pipe, especially the lower part of the horizontal pipe. Because it causes pore-like corrosion (pitting corrosion) from the inside to the outside of the piping, it has a relatively fast traveling speed and can cause fatal damage to the condensate piping in a short time. ing.

  For this reason, as a measure for preventing corrosion of the condensate pipe, a neutralizer for neutralizing carbon dioxide in the condensate, a film forming agent for forming an anticorrosive film on the inner surface of the condensate pipe, etc. A method using a chemical (condensate treatment agent) has been proposed. However, since these chemicals need to be added to the steam generated in the steam boiler, the purity of the steam is lowered, and there is also a sanitary problem when steam is used in the food and medical fields. is there.

  If the condensate pipe is made of stainless steel, corrosion can be suppressed without the above-mentioned chemicals, but such a condensate pipe is very expensive and lacks practicality.

  An object of the present invention is to suppress corrosion of a condensing pipe for a steam boiler without using a chemical.

  A steam boiler apparatus according to the present invention includes a steam boiler, a water supply tank having an exhaust port for storing supply water supplied to the steam boiler, a supply path for supplying supply water to the steam boiler, and a water supply tank A water injection channel for replenishing the supply water stored in the water supply tank, a condensate pipe for sending condensate obtained by condensing steam from the steam boiler, and a condensate from the condensate pipe A condensate tank having an exhaust port for storing water, a communication path for supplying the condensate stored in the condensate tank to the water supply tank, and the supply water and condensate tanks stored in the water supply tank And an inert gas supply device capable of individually supplying and ejecting the inert gas in the condensate stored in the water.

  The condensate tank has, for example, a net-like packing layer for dropping the condensate from the condensate pipe into droplets.

  A steam boiler apparatus according to the present invention includes an inert gas supply device capable of individually supplying and ejecting inert gas in supply water stored in a water supply tank and in condensate water stored in a condensate tank. Therefore, corrosion of the condensate piping and the steam generation system can be suppressed without using chemicals.

Embodiment 1
With reference to FIG. 1, the steam boiler apparatus which concerns on one Embodiment of this invention is demonstrated. In the figure, the steam boiler device 1 mainly includes a steam boiler 2, a water supply tank 3, a heat exchanger 4, a condensate piping device 20, and an inert gas supply device 21.

  The water supply tank 3 is a tank for storing water (supply water) supplied to the steam boiler 2, and has a supply path 6 that communicates with the steam boiler 2. Further, the water supply tank 3 communicates with a water injection path 12 for replenishing the supply water, and an exhaust port 3a is provided at the upper part. The heat exchanger 4 is for performing necessary heat exchange using the steam from the steam boiler 2, that is, a load device in the steam boiler apparatus 1, and communicates with the steam supply pipe 7 from the steam boiler 2. ing.

  The condensate piping device 20 has a steam recovery pipe 8 for recovering steam that has passed through the heat exchanger 4, and a steam trap 9 for obtaining condensate (drain water) in which steam from the steam recovery pipe 8 is condensed. A condensate pipe 10 and a condensate tank 11 are mainly provided. The condensate tank 11 is for collecting and storing the condensate obtained in the steam trap 9 through the condensate pipe 10, and is disposed adjacent to the water supply tank 3. The condensate tank 11 has a communication path 13 for supplying the stored condensate to the water supply tank 3. Further, an exhaust port 11 a is provided in the upper part of the condensate tank 11.

  The inert gas supply device 21 mainly includes an inert gas generation device 14 and an inert gas supply path 22. The inert gas generator 14 is, for example, a cylinder filled with an inert gas or a known inert gas generator, and supplies the inert gas to the inert gas supply path 22. Further, the inert gas supply path 22 is bifurcated, one supply path 22 a extends into the water supply tank 3, and the other supply path 22 b extends into the condensate tank 11. Both supply passages 22a and 22b are set so that the inert gas from the inert gas generator 14 can be ejected in the form of fine bubbles in the supply water or condensate stored in both tanks 3 and 11. ing.

  The inert gas supplied from the inert gas generator 14 is not particularly limited, and may be various types such as nitrogen, helium, neon, argon, krypton, and xenon, but is easily mass-produced and inexpensive. Nitrogen gas is preferably used. Incidentally, when nitrogen is used as the inert gas, for example, a PSA nitrogen generator by a pressure swing absorption method can be used as the generator.

  In addition, the various members which comprise the above-mentioned steam boiler apparatus 1, especially the supply path 6, the steam supply pipe 7, the steam collection pipe 8, and the condensate pipe 10 are mainly formed using the steel pipe.

Next, operation | movement of the above-mentioned steam boiler apparatus 1 is demonstrated.
First, makeup water is poured from the water injection channel 12 into the water supply tank 3. Here, the replenishing water to be poured is usually water softened in advance using a water softener, and the dissolved oxygen concentration is lowered using a degassing device. In addition, it is preferable that the dissolved oxygen concentration in make-up water is normally set to about 0.5 mg / l.

  The makeup water poured into the water supply tank 3 is stored in the water supply tank 3 as supply water. The supply water stored in the water supply tank 3 is supplied to the steam boiler 2 through the supply path 6. The supply water supplied to the steam boiler 2 becomes steam there and is supplied to the heat exchanger 4 through the steam supply pipe 7 and used for required heat exchange. The steam that has passed through the heat exchanger 4 subsequently loses its latent heat while passing through the steam recovery pipe 8 and is partially converted into condensed water. The steam and water are separated in the steam trap 9 and condensed water (drain water). become. This condensate is stored in the condensate tank 11 through the condensate pipe 10. The stored condensate is supplied into the water supply tank 3 through the communication path 13.

  On the other hand, during the operation of the steam boiler apparatus 1 as described above, the inert gas generator 14 is operated, and the inert gas therefrom is supplied into the water supply tank 3 and the condensate tank 11 through the inert gas supply path 22. Blow continuously. The inert gas blown into the water supply tank 3 from the supply passage 22a rises in the supply water in the water supply tank 3 and is discharged to the upper part (on the water surface) in the water supply tank 3 while being ejected as fine bubbles. Further, it is discharged to the outside from the exhaust port 3a. On the other hand, the inert gas blown into the condensate tank 11 from the supply path 22b rises in the condensate stored while being ejected in the form of fine bubbles, and the upper part of the condensate tank 11 (on the water surface). And a part flows into the condensate pipe 10 and a part is discharged to the outside through the exhaust port 11a. In addition, the exhaust port 3a of the water supply tank 3 and the exhaust port 11a of the condensate tank 11 are sealed with the inert gas discharged | emitted from there, and inflow of external air is prevented. Therefore, the condensate pipe 10, the condensate tank 11, the water supply tank 3, and the supply path 6 form a series of closed environments isolated from the outside air, and the inflow of the outside air is prevented. Thereby, the condensate or supply water in the condensate pipe 10, the feed water tank 3, the condensate tank 11, and the supply path 6 is prevented from coming into contact with the outside air, and oxygen and carbon dioxide contained in the outside air are dissolved. This prevents the dissolved oxygen concentration and carbon dioxide concentration from rising.

  During the operation of the steam boiler apparatus 1 as described above, the supply water stored in the feed water tank 3 and the oxygen and carbon dioxide dissolved in the condensate stored in the condensate tank 11 are supplied to the supply path 22a and The feed water or the condensate rises together with the inert gas ejected from the supply path 22b, and is discharged to the outside through the exhaust ports 3a and 11a. As a result of the above, the supply water and condensate are set so that the dissolved oxygen concentration and the carbon dioxide concentration are lower, and the supply path 6, the steam boiler 2, the steam supply pipe 7, the heat exchanger 4 and the steam recovery pipe 8 (hereinafter, generalized). This is called “steam generation system”).

  Further, the inert gas that has flowed into the condensate pipe 10 lowers the partial pressures of oxygen and carbon dioxide in the gas phase portion within the condensate pipe 10. Along with this, dissolved oxygen and carbon dioxide in the condensate flowing in the condensate pipe 10 are released into the inert gas in the gas phase according to Henry's law. As a result, the dissolved oxygen concentration and the carbon dioxide concentration in the condensate flowing through the condensate pipe 10 are lowered.

  As described above, since the inert gas supply device 21 supplies the inert gas into the condensate pipe 10, the concentration of dissolved oxygen and carbon dioxide, which are corrosion factors contained in the condensate in the condensate pipe 10. Thus, corrosion of the condensate pipe 10 due to condensate, in particular, uniform thinning corrosion and pitting corrosion of the inner surface of the condensate pipe 10 can be suppressed at the same time. In addition, this condensate is stored in the condensate tank 11 in a state in which contact with outside air is prevented, and is reused as part of the supply water. However, as described above, the concentration of the corrosion factor is reduced. It is difficult to increase the dissolved oxygen concentration and carbon dioxide concentration in the feed water. Therefore, the feed water mixed with this condensate is unlikely to corrode the condensate pipe 10 and the steam generation system.

  As described above, since the steam boiler apparatus 1 according to this embodiment supplies the inert gas from the inert gas generator 14 to the water supply tank 3 and the condensate tank 11 separately, both tanks The dissolved oxygen and carbon dioxide contained in the supply water and condensate stored in the tanks 3 and 11 can be effectively removed, and the amount of inert gas supplied into the condensate pipe 10 can be easily adjusted. For this reason, this steam boiler apparatus 1 can effectively suppress corrosion of the condensate pipe 10 and the steam generation system.

By the way, carbon dioxide (CO ₂ ) contained in water changes in phase as follows with a change in pH.

  If the pH of water containing carbon dioxide is increased and the phase of carbon dioxide changes to bicarbonate ions, it becomes difficult to remove the carbon dioxide from the water even if an inert gas is blown. In consideration of this point, in this embodiment, the condensate that has been previously treated with the inert gas in the condensate tank 11 is supplied to the water supply tank 3. According to this, the inert gas is blown in with the pH of the condensate being low, and the carbon dioxide gas is easily removed from the condensate. The condensate thus treated is then mixed with make-up water in the water supply tank 3, so that the amount of carbon dioxide gas converted to hydrogen carbonate ions can be kept very low, and the carbon dioxide brought from the condensate as a whole. Gas removal efficiency is increased. Therefore, according to this embodiment, the concentration of carbon dioxide gas in the feed water supplied to the steam boiler 2 can be further reduced, so that the corrosion of the condensate pipe 10 and the steam generation system is more effectively suppressed. be able to.

  When the operation of the steam boiler apparatus 1 is stopped, the inside of the condensate pipe 10 becomes negative pressure due to a temperature drop, so that outside air flows from the exhaust port 11a of the condensate tank 11 and the outside air enters the condensate pipe 10. There is a possibility of inflow. In this case, the partial pressure of oxygen and carbon dioxide increases in the gas phase portion in the condensate pipe 10, and accordingly, the dissolved oxygen concentration and carbon dioxide concentration in the condensate increase and corrosion of the condensate pipe 10 proceeds. there is a possibility. For this reason, in the steam boiler apparatus 1, it is preferable to operate the inert gas generator 14 continuously even when the operation of the steam boiler 2 is stopped. In this way, since the inert gas is always supplied to the gas phase portion in the condensate tank 11 and the condensate pipe 10, the inflow of outside air from the exhaust port 11a is prevented, and the condensate pipe 10 Corrosion can be more effectively suppressed.

Embodiment 2
A steam boiler apparatus 1 according to another embodiment of the present invention is shown in FIG. The condensate piping device 30 used in the steam boiler device 1 is a modification of the condensate piping device 20 in the first embodiment. In FIG. 2, the same reference numerals are used for the portions corresponding to FIG. .

  The condensate piping device 30 used in the steam boiler device 1 is a steam recovery pipe 8 for recovering steam that has passed through the heat exchanger 4, and condensate (drain water) in which steam from the steam recovery pipe 8 is condensed. A condensate pipe 10 having a steam trap 9 for obtaining and a decarboxylation tower 31 (an example of a condensate tank) are mainly provided.

  The decarboxylation tower 31 has a net-like packing layer 32 for dropping the condensate from the condensate pipe 10 into droplets and dropping it to the bottom, and drops from the packing layer 32 at the bottom. Condensate can be stored.

  The inert gas supply path 22 extending from the inert gas generator 14 of the inert gas supply apparatus 21 is bifurcated, one supply path 22a extends into the water supply tank 3, and the other supply path. 22 b extends to the bottom of the decarboxylation tower 31. Both supply passages 22a and 22b are set so that the inert gas can be ejected in the form of fine bubbles in the supply water stored in the water supply tank 3 or in the condensate stored in the decarbonation tower 31. Yes.

  In this condensate piping device 30, the condensate flowing from the condensate piping 10 into the decarbonation tower 31 is dropped in the form of droplets through the packing layer 32, so that it is stored in the bottom of the decarbonation tower 31. In addition, the gas passes through the inert gas atmosphere from the supply path 22b toward the exhaust port 11a. Therefore, oxygen and carbon dioxide dissolved in the dripping condensate are further released into the inert gas in the process, and dissolved oxygen concentration and carbon dioxide concentration are present at the bottom of the decarbonation tower 31. A smaller condensate will be stored. For this reason, the steam boiler apparatus 1 using the condensate piping device 30 is more effective in corroding the condensate piping 10 and the steam generation system than when the condensate piping device 20 according to the second embodiment is used. To be suppressed.

[Other embodiments]
(1) In each of the above-described embodiments, as shown in FIG. 3, a cylindrical body 60 extending in the vertical direction is disposed inside the condensate tank 11, and the condensate pipe 10 is hermetically sealed at the upper end portion of the cylindrical body 60. The inert gas from the inert gas supply device 21 can also be set to be separately supplied into the cylindrical body 60. In addition, the lower end part of the cylindrical body 60 is arrange | positioned in the condensate stored in the condensate tank 11, and it sets so that it may be sealed by it. In this way, even if the condensate stored in the condensate tank 11 undergoes a significant fluctuation in the water level, the inflow of outside air into the condensate pipe 10 can be more effectively suppressed. .

  For example, when the water level rises, the nitrogen gas in the condensate tank 11 is discharged to the outside from the exhaust port 11a. Conversely, when the water level falls, outside air flows into the condensate tank 11 from the exhaust port 11a. For this reason, in order to prevent the inflow of outside air when the water level is lowered and maintain the above-described closed environment, a large amount of inert gas is instantaneously supplied from the inert gas supply device 21 to the condensate tank 11 as the water level is lowered. It is necessary to set the gas phase portion in the condensate tank 11 to a pressurized state with an inert gas.

  On the other hand, if the condensate from the condensate pipe 10 is set to be stored in the condensate tank 11 through the cylindrical body 60 as described above, outside air will not easily flow into the condensate pipe 10, and The water pipe 10, the condensate tank 11, the water supply tank 3, and the supply path 6 can stably maintain a series of closed environments isolated from the outside air. Therefore, in this embodiment, corrosion of the condensate pipe 10 and the steam generation system can be further effectively suppressed.

(2) In the first embodiment described above, the condensate tank 11 can be configured in two stages as shown in FIG. In this case, the first-stage condensate tank 11b and the second-stage condensate tank 11c are adjacent to each other, and both the condensate tanks 11b and 11c are connected using the connecting pipe 11d, and inactive between the both condensate tanks 11b and 11c. A gas communication pipe 11e is arranged. Further, the communication path 13 with the water supply tank 3 is connected to the second stage condensate tank 11c. The inert gas is supplied to the second stage condensate tank 11c side according to the example of the first embodiment.

When the condensate tank 11 is configured in two stages in this way, the dissolved oxygen and carbon dioxide contained in the condensate are more effectively removed, so that the condensate pipe 10 and the steam generation system are more corroded. It can be effectively suppressed.
In addition, the condensate tank 11 can also be set to the multistage of 3 steps or more as needed.

(3) In each of the above-described embodiments, it is preferable that the float material floating on the surface of the stored supply water or condensate is densely arranged in the water supply tank 3 and the condensate tank 11. In this case, even if the outside air flows into the water supply tank 3 or the condensate tank 11, the stored supply water or condensate is less likely to come into direct contact with the outside air. An increase in carbon dioxide concentration can be suppressed.

(4) In each above-mentioned embodiment, in the feed water tank 3 and the condensate tank 11, the stirring apparatus for stirring the stored supply water and condensate can be installed. When such a stirrer is installed, the feed water and condensate come into more efficient contact with the inert gas, and the dissolved oxygen concentration and the dissolved carbon dioxide gas concentration decrease. Corrosion can be more effectively suppressed.

1 is a schematic diagram of a steam boiler apparatus according to Embodiment 1 of the present invention. The schematic of the steam boiler apparatus which concerns on Embodiment 2 of this invention. Schematic of the modification of the condensate tank used in said each embodiment. Schematic of the modification of the condensate tank used in the steam boiler apparatus of the said Embodiment 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steam boiler apparatus 2 Steam boiler 3 Water supply tank 3a Exhaust port 6 Supply channel 10 Condensate piping 11 Condensate tank 11a Exhaust port 12 Inlet channel 13 Connection channel 20, 30 Condensate piping device 21 Inert gas supply device 31 Decarbonation tower 32 Filling layer

Claims (2)

A steam boiler,
A supply path for supplying the supply water to the steam boiler, having a water supply tank having an exhaust port for storing the supply water supplied to the steam boiler;
A water injection channel for replenishing the supply water stored in the water supply tank, in communication with the water supply tank;
A condensate pipe for sending condensate obtained by condensing steam from the steam boiler;
A condensate tank having an exhaust port for storing the condensate from the condensate pipe;
A communication path for supplying the condensate stored in the condensate tank to the water supply tank;
An inert gas supply device capable of individually supplying and ejecting an inert gas in the supply water stored in the water supply tank and in the condensate stored in the condensate tank;
Steam boiler device equipped with. The steam boiler apparatus according to claim 1, wherein the condensate tank has a net-like packing layer for dropping the condensate from the condensate pipe into droplets.

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