JP5083978B2 - Nitrogen deoxygenation equipment - Google Patents

Description

The present invention relates to nitrogen type deoxygenating device for removing in advance oxygen in raw water supplied to the boiler or the like, in particular de-oxygen treatment by contact with nitrogen gas (hereinafter, deoxidation means deoxygenation) performing The present invention relates to a nitrogen deoxygenation apparatus.

  In the field of water treatment such as boiler water supply, deoxygenation treatment is performed to prevent corrosion of boilers and piping caused by dissolved oxygen in water, and one method is nitrogen. As described in Patent Document 1, the nitrogen-type deoxygenation device removes dissolved oxygen in raw water by bringing the raw water into contact with nitrogen gas. There are various contact methods between raw water and nitrogen gas, and in Patent Document 1, a counter-flow type treatment tower in which a gas-liquid contact tower is connected to a water tank is used.

JP 2005-95791 A

  A typical system configuration of a conventional nitrogen deoxygenation apparatus will be described with reference to FIG. 3 for boiler water. The nitrogen-type deoxygenation apparatus is provided in a boiler water supply system 20 that extends from a raw water tank 10 that stores raw water to be deoxidized to a boiler through a boiler pump 21, and has a deoxidizer main body 30 as a main component. ing. The deoxidizer body 30 is supplied with raw water through a raw water supply system 40 that feeds the raw water in the raw water tank 10 with a supply pump 31, and nitrogen gas is supplied from a nitrogen gas source through a gas supply system 50. The

  The raw water supplied from the raw water tank 10 through the raw water supply system 30 to the deoxidation apparatus main body 30 comes into contact with nitrogen gas supplied through the gas supply system 50 in the deoxidation apparatus main body 30 to remove oxygen in the raw water. Is done. The treated water that has been subjected to the deoxidation treatment in the deoxidizer main body 30 is supplied to a point A upstream of the boiler pump 21 in the boiler feed water system 20 by the treated water supply system 60 including the treated water pump 61. .

  By the way, on the boiler side, a necessary amount of treated water is supplied by the control of the boiler pump 21, but the amount varies greatly. That is, the load fluctuation is large on the boiler side. On the other hand, in the deoxidizer, the deoxidizer main body 30, the supply pump 31, and the treated water pump 61 operate with the same capacity, and always send the same amount of treated water to the boiler feed water system 20. The supply amount here is set larger than the maximum consumption amount of the treated water so that the treated water does not run short on the boiler side. As a result, an amount of treated water corresponding to the consumption amount is always secured on the boiler side, but surplus treated water is always generated on the deoxygenation device side, and this surplus water is generated from the treated water confluence point A in the boiler water supply system 20. It returns to the raw water tank 10 through the upstream piping. Thus, the difference between supply and consumption is absorbed.

  Such a conventional nitrogen-type deoxygenation device can always supply sufficient treated water to the boiler. Nitrogen-type deoxygenation equipment is an auxiliary equipment for boilers. Supplying treated water without excess or deficiency to the boiler equipment, which is the main equipment, is the most important accessory equipment, but the consumption on the boiler side is large. If it decreases, the excessive reflux amount on the deoxidizer side becomes very large, and the operation cost of the equipment including the deoxidizer main body 30, the supply pump 41, and the treated water pump 61 becomes unnecessarily high, and the economic efficiency deteriorates. To do.

  An object of the present invention is to provide an economical nitrogen deoxygenation apparatus that can supply treated water without excess and deficiency to the treated water consumption side, and that can keep facility operating costs low. Another object of the present invention is to provide a highly self-contained nitrogen-type deoxygenation apparatus that minimizes design changes on the raw water supply side and the treated water consumption side in order to keep facility operating costs low.

To achieve the above object, a nitrogen type deoxygenating device of the present invention, is attached to a water supply system leading through the water supply pump from the raw water tank for storing raw water to be deoxygenated to raw water consumption unit, the raw water consumption unit A nitrogen-type deoxygenation device that removes oxygen in the raw water to be supplied in advance, connected to a raw water supply system that feeds the raw water in the raw water tank by a supply pump, and is supplied from a nitrogen gas source through a gas supply system nitrogen gas, by contacting the raw water supplied through the raw water supply system, a deoxidation device body to remove oxygen in raw water, raw water consumption treated water having been subjected to deoxidation treatment in deacidification device body in order to supply to the parts, and treated water supply system that supplies upstream from the water supply pump in the treated water the water supply system by treated water pump, the water of the treated water supplied to the upstream side of the water supply pump in the water supply system In the raw water consumption department With more than the amount of water, a part of the treated water, along with back through the upstream side to the raw water tank from the treated water confluence treated water in the water supply system is supplied, the return amount of the raw water tank treated water And a control unit for controlling the capacity of the treated water pump so as to be maintained within a predetermined range.

  In the nitrogen-type deoxygenation apparatus of the present invention, the treated water is sent to the feed water system by the operation of the treated water pump in the treated water supply system, and a necessary amount of treated water is consumed in the raw water consumption unit. The surplus of the supply amount with respect to the consumption amount of the treated water is returned to the raw water tank through a pipe upstream from the treated water confluence in the water supply system. At this time, the capacity of the treated water pump is controlled by the control unit so that the return amount of the treated water supplied to the feed water system to the raw water tank is maintained within a predetermined range. Thereby, the surplus is kept within a predetermined range regardless of the load fluctuation in the raw water consumption section. In other words, the amount of treated water obtained by adding a predetermined surplus to the amount consumed in the raw water consumption unit is supplied to the water supply system.

  In order to keep the surplus within the specified range, a return water flow meter that measures the return amount of treated water to the raw water tank is usually attached to the pipe upstream of the treated water confluence in the water supply system. The capacity of the treated water pump is controlled so that the return amount of the treated water measured by the flow meter is maintained within a predetermined range. When an accurate signal of consumption can be obtained from the raw water consumption unit, the treated water pump can be controlled with the treated water amount obtained by adding a predetermined surplus to the consumed amount as a target value. In any case, by maintaining the return amount to the raw water tank within the predetermined range, the risk of the supply amount being insufficient in the raw water consumption section is avoided, and the operation cost of the treated water pump is minimized. It is suppressed.

  By controlling the supply pump in the raw water supply system in conjunction with the treated water pump, it is possible to supply an amount of raw water commensurate with the amount to be treated to the deoxidizer body, thus reducing the operating costs of the supply pump and the deoxidizer body. It can be further reduced.

  The gas supply system has a gas amount control mechanism that controls the amount of nitrogen gas supplied to the deoxidizer main body, and the control unit is configured to remove nitrogen gas in an amount corresponding to the raw water treatment amount in the deoxidizer main body. The gas amount control mechanism is preferably controlled based on the raw water treatment amount so as to be supplied to the main body. Thereby, also about the usage-amount of nitrogen gas, it can suppress to the required minimum quantity according to the raw water processing amount.

  At this time, it is preferable that the control unit controls the gas amount control mechanism based on the raw water temperature together with the raw water treatment amount in the deoxidizer main body. When the raw water temperature increases, the solubility of nitrogen gas in the raw water decreases, and conversely, when the raw water temperature decreases, the solubility of nitrogen gas in the raw water increases. For this reason, by controlling the gas amount control mechanism based on the raw water temperature, the amount of nitrogen gas corresponding to the solubility is supplied to the deoxidizer body, and the excess or deficiency of nitrogen gas in the deoxidizer body is further reduced. As a result, it is possible to further reduce the amount of nitrogen gas used while maintaining a high deoxidation capacity in the deoxidizer main body.

  The control unit is also preferably configured to control the supply pump in the raw water supply system together with the treated water pump, and more specifically, the treated water in which the raw water treatment amount in the deoxidizer main body is supplied from the deoxidizer main body to the feed water system. The structure which controls the supply pump in a raw | natural water supply system so that it may correspond to the flow volume of this is preferable. The raw water treatment amount in the deoxidizer main body is a flow rate of treated water supplied from the deoxidizer main body to the feed water system, and can be detected by a treated water flow meter provided on the downstream side of the treated water pump. Moreover, it can detect also from the rotation speed of a treated water pump. The capacity of the treated water pump is the rotation speed of the pump.

  The nitrogen-type deoxygenation apparatus of the present invention joins treated water treated by the deoxidizer body by a treated water supply system upstream of a feed water pump in a feed water system from a raw water tank via a feed water pump to a raw water consumption unit. Therefore, the amount of treated water supplied to the water supply system is made larger than the amount of raw water used in the raw water consumption section, and a part of the treated water is returned to the raw water tank through the upstream side from the treated water confluence in the water supply system. By controlling the capacity of the treated water pump in the treated water supply system so that the amount of treated water returned to the tank is maintained within the specified range, a shortage of supply in the raw water consumption section can be avoided reliably. However, the operating cost of the treated water pump can be minimized. Moreover, since the treated water pump in the said apparatus is controlled, a series of control can be performed substantially in the said apparatus and the installation construction on the spot is easy.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a nitrogen deoxygenation apparatus showing an embodiment of the present invention, and FIG. 2 is a configuration diagram of a control unit in the nitrogen deoxygenation apparatus.

  As shown in FIG. 1, the nitrogen-type deoxygenation apparatus of the present embodiment desorbs raw water using nitrogen gas from a nitrogen source when supplying raw water in the raw water tank 10 to a boiler which is a raw water consuming unit. It is an acid treatment. The raw water tank 10 is connected to the boiler by a boiler water supply system 20 having a boiler water supply pump 21.

  This nitrogen-type deoxygenation device is attached to an existing boiler water supply system 20 and performs deoxygenation treatment of raw water. In the deoxidation device main body 30 connected to the raw water supply system 40, In order to supply the boiler with a gas supply system 50 for supplying nitrogen gas to the main body for deoxidation treatment, and for treating water treated by the deoxidizer main body 30 to the boiler, the boiler water supply system 20 And a return water flow meter 22 interposed in the boiler water supply system 20 in order to control the supply amount of the treated water.

  The raw water supply system 40 supplies the raw water in the raw water tank 10 to the deoxidizer main body 30 by the raw water supply pump 41. The deoxidizer main body 30 performs deoxygenation treatment by bringing the raw water supplied through the raw water supply system 40 into contact with nitrogen gas supplied from the nitrogen gas source through the gas supply system 50. In order to measure the temperature of raw water supplied to the deoxidizer main body 30, the deoxidizer main body 30 is equipped with a thermometer 31. The gas supply system 50 has a flow rate control valve 51 called a mass flow valve in order to adjust the gas supply amount from the gas source to the deoxidizer main body 30. A pressure reducing valve 52 is provided on the upstream side of the flow control valve 51.

The supply water supply system 60 is a conduit for supplying the treated water, which has been treated by the deoxidizer main body 30, to the boiler via the boiler water supply system 20, and is upstream from the boiler feed pump 21 in the boiler water supply system 20. It joins the boiler water supply system 20 at the treated water confluence A on the side (hereinafter simply referred to as the confluence A) . The supply water supply system 60 is equipped with a treated water pump 61 in the middle of the pipeline, and a treated water flow meter downstream of the treated water pump 61 for controlling the flow control valve 51 in the gas supply system 50. Equipped with 62. The return water flow meter 22 is connected to the boiler water supply system 20 upstream from the confluence point A where the supply water supply system 60 joins the boiler water supply system 20, that is, between the confluence point A in the boiler water supply system 20 and the raw water tank 10. A one-way valve 23 in the reverse direction from the raw water tank 10 to the confluence A is interposed in the pipe line.

  In the nitrogen-type deoxygenation apparatus of the present embodiment, the treated water pump 61 in the supply water supply system 60, the flow rate control valve 51 in the gas supply system 50, the supply pump 41 in the raw water supply system 40, and various types in the deoxidizer main body 30. Power equipment is controlled. These controls are executed by the control unit 70. In order to execute the control, the control unit 70 takes in the flow rate signals from the return water flow meter 22 in the boiler feed water system 20 and the treated water flow meter 62 in the supply water supply system 60, and in the deoxidizer main body 30. The raw water temperature signal is taken in from the thermometer 31. Moreover, the power equipment in the treated water pump 61, the supply pump 41, and the deoxidation apparatus main body 30 to be controlled is a structure which can change arbitrarily rotation speed by the frequency control by an inverter.

  Next, the basic operation and control operation of the nitrogen-type deoxygenation apparatus of the present embodiment will be described.

  The basic operation is as follows. By operating the supply pump 41 in the raw water supply system 40, the raw water in the raw water tank 10 is supplied to the deoxidizer main body 30. Further, nitrogen gas is supplied from the nitrogen gas source to the deoxidizer main body 30 via the gas supply system 50. In the deoxidizer main body 30, the raw water is deoxidized when both come in countercurrent contact.

The treated water that has been subjected to the deoxidation treatment in the deoxidizer main body 30 is sent to the confluence point A in the boiler water supply system 20 through the supply system by the operation of the treated water pump 61 in the treated water supply system 60. . The treated water flow rate Q ₁ supplied to the boiler feed water system 20 is measured by the flow meter 52. As will be described in detail later, the treated water flow rate Q ₁ is a flow rate obtained by adding a predetermined surplus to the consumption amount in the boiler. For this reason, most of the treated water supplied to the boiler water supply system 20 is supplied to the boiler by the boiler water supply pump 21. Excess treated water is returned to the raw water tank 10 from the junction A through the upstream piping. The return flow rate Q ₂ of the treated water is measured by the flow meter 62.

The control operation is as follows. The return amount Q ₂ of the treated water is measured by the flow meter 22 in the boiler water supply system 20. The treated water flow rate Q ₁ is measured by the flow meter 62 in the treated water supply system 60. The raw water temperature T is measured by a thermometer 31 in the deoxidizer main body 30. Control unit 70, as shown in FIG. 2, so that the return amount Q ₂ is maintained within a predetermined range, the rotational speed X of the treated water pump 61, obtained by calculation based on the return amount Q _2, was determined rotation The treated water pump 61 is controlled and operated with the number X, and the supply pump 41 in the raw water supply system 40 is controlled and operated in synchronization therewith.

That is, the rotational speed X of the treated water pump 60 corresponds to the raw water treatment amount in the deoxidizer main body 30. The control unit 70 rotates the supply pump 41 in the raw water supply system 40 necessary to secure an appropriate raw water introduction amount Q ₃ corresponding to the raw water treatment amount in the deoxidizer main body 30 and the raw water introduction amount Q _3. The number and the rotational speed of the power equipment in the deoxidizer main body 30 are calculated from the rotational speed X using a previously calculated arithmetic expression, and the power equipment in the supply pump 41 and the deoxidizer main body 30 is calculated based on the calculated rotational speed. To control.

With this control, the return amount Q ₂ of the treated water is managed within a predetermined range regardless of the consumption amount of the treated water in the boiler. For this reason, there is no shortage of treated water in the boiler. Then, the treated water pump 61 is always by operating the return amount Q ₂ at the load necessary to maintain within a predetermined range, it can be realized savings operating costs. Further, the supply pump 41 in the raw water supply system 40 and the power equipment in the deoxidizer main body 30 are controlled in synchronism with the treated water pump 61 so that the raw water treatment amount in the deoxidizer main body 30 is excessive or insufficient. It is possible to reduce these operating costs by driving with the capacity that is not.

The treated water flow rate Q1 measured by the flow meter 62 in the treated water supply system 60 also corresponds to the raw water treatment amount in the deoxidizer main body 30. The control unit 70 calculates the raw water treatment amount and the raw water temperature in the deoxidizer main body 30 from the treated water flow rate Q1 measured by the flow meter 62 and the raw water temperature T measured by the thermometer 31 by using an arithmetic expression obtained in advance. A suitable nitrogen gas supply amount is calculated, and an opening degree of the flow control valve 51 in the gas supply system 50 necessary for securing the calculated nitrogen gas supply amount is calculated. And the flow control valve 51 is controlled to the opening degree.

  Thereby, also about nitrogen gas, the quantity without excess and deficiency is supplied to the deoxidizer main body 30, and the reduction of nitrogen gas cost is aimed at.

  In terms of facility construction, a nitrogen-type deoxygenation device is generally in a range indicated by a one-dot chain line in FIG. What does not belong to the apparatus is only the installation of the flow meter 22 in the boiler water supply system 20 and the control of the supply pump 41 in the raw water supply system 40. After that, construction work can be performed in the apparatus. Further, the installation of the flow meter 22 and the control of the supply pump 41 can be performed in the vicinity of the apparatus near the raw water tank 10. Therefore, it can be said that the nitrogen-type deoxygenation apparatus of this embodiment is a substantially self-contained construction type deoxygenation apparatus.

Furthermore, by providing a one-way valve 23 in a reverse direction in parallel with the flow meter 22, the raw water in the raw water tank 10 is supplied to the boiler as in the case where the operation of the nitrogen-type deoxygenation apparatus is stopped. If the one-way valve 23 is used, the flow meter 22 can be used on a small scale corresponding to the return amount Q ₂ of the treated water. The one-way valve 23 may be an on-off valve, and if these are not present, a flow meter 22 having a scale corresponding to the consumption in the boiler is required.

The treated water was actually supplied to the boiler using the nitrogen type deoxygenation apparatus shown in FIGS. The water temperature of the raw water is 40 to 80 ° C., and the dissolved oxygen concentration is 2.5 to 6.5 mg / L. The amount of treated water used in the boiler varied between 20 and 50 m ³ / hr. The dissolved oxygen concentration of the treated water was 0.1 mg / L or less, and the return amount to the raw water tank was controlled within the range of 1 to ³ m ³ / hr. For this management, the power equipment in the treated water pump 61, the supply pump 41, and the deoxidizer main body 30 was controlled. Moreover, the opening degree of the flow control valve 51 in the gas supply system 50 was controlled based on the amount of treated water.

By these controls, the amount of treated water in the deoxidizer main body 30 changes greatly between 21 to 53 m ³ / hr, and the operating costs of the treated water pump 61, the supply pump 41, and the power equipment in the deoxidizer main body 30 are It was reduced by about 65% compared to before control. Further, the amount of nitrogen gas used was reduced by about 70% compared to before the control. Incidentally, the amount of treated water in the conventional deoxidizer main body 30 is 53 m ³ / hr (constant). The flow rate of nitrogen gas is proportional to the amount of treated water, but the power is proportional to the third power of the treated water amount. Therefore, the influence of the decrease in the treated water amount on the reduction in power cost is significant.

It is a block diagram of the nitrogen-type deoxygenation apparatus which shows one Embodiment of this invention. It is a block diagram of the control part in the same nitrogen-type deoxygenation apparatus. It is a schematic block diagram of the conventional nitrogen type deoxygenation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Raw water tank 20 Boiler water supply system 21 Feed water pump 22 Return water flow meter 30 Deoxidizer main body 31 Thermometer 40 Raw water supply system 41 Supply pump 50 Gas supply system 51 Flow control valve 60 Process water supply system 61 Process water pump 62 Flow meter 70 Control unit

Claims (6)

Is attached to a water supply system from the raw water tank for storing raw water to be deoxygenated leading to the raw water consumption unit through a feed water pump, a nitrogen type deoxygenating device for removing in advance oxygen in raw water supplied to the raw water consumption unit And
The raw water in the raw water tank is connected to a raw water supply system that sends out the raw water by a supply pump, and the nitrogen gas supplied from the nitrogen gas source through the gas supply system is brought into contact with the raw water supplied through the raw water supply system. A deoxidizer body for removing oxygen in the raw water,
In order to supply the treated water having been subjected to deoxidation treatment in deacidification device main body to the raw water consumption unit, a treated water supply system that supplies upstream from the water supply pump in the treated water the water supply system by treated water pump, water with more than the amount of the raw water in the raw water consumption section the water of the treated water supplied to the upstream side of the water supply pump in the system, a portion of the treated water, treated water confluence treated water in the water supply system is supplied A nitrogen-type deoxygenation apparatus comprising: a controller that controls the capacity of the treated water pump so that the amount of the treated water returned to the raw water tank is maintained within a predetermined range while returning to the raw water tank through the upstream side.   2. The nitrogen deoxygenation device according to claim 1, wherein the control unit is interposed upstream of the treated water confluence in the water supply system and measures the return amount of the treated water to the raw water tank. Nitrogen type that receives the flow rate signal from the meter and controls the capacity of the treated water pump based on the treated water return amount so that the treated water return amount measured by the return water flow meter is maintained within a predetermined range Deoxygenation device.   The nitrogen-type deoxygenation apparatus according to claim 1, wherein the control unit controls a supply pump in the raw water supply system together with a treated water pump.   4. The nitrogen-type deoxygenation apparatus according to claim 3, wherein the control unit is configured to supply raw water so that a raw water treatment amount in the deoxidation apparatus main body matches a flow rate of treated water supplied from the deoxidation apparatus main body to a water supply system. A nitrogen-type deoxygenation device that controls a supply pump in the supply system.   2. The nitrogen type deoxygenation apparatus according to claim 1, wherein the gas supply system includes a gas amount control mechanism that controls a nitrogen gas supply amount to a deoxidation apparatus main body, and the control unit includes a deoxidation apparatus. A nitrogen-type deoxygenation device that controls the gas amount control mechanism based on the raw water treatment amount so that an amount of nitrogen gas corresponding to the raw water treatment amount in the main body is supplied to the deoxidizer main body.   6. The nitrogen type deoxygenation apparatus according to claim 5, wherein the control unit controls the gas amount control mechanism based on a raw water treatment amount and a raw water temperature in a deoxidation apparatus main body.

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