JP2008157577A - Makeup water supply method for boiler water supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve certainty in softening and deoxidizing the makeup water in supplying the makeup water to a water storage tank to supply the water to a boiler. <P>SOLUTION: In a water softening device 53 disposed in a water pouring passage 51 for supplying the makeup water to the water storage tank 40, one resin unit is selected from a group of resin units filled with sodium-type cation-exchange resin, and a hard component is eliminated from the makeup water by using the selected resin unit. The makeup water, from which the hard component is eliminated is made to pass through a deoxidizing device 56 at a prescribed flow rate X to eliminate dissolved oxygen included in the makeup water, and then the makeup water is supplied to the water storage tank 40 to be stored. A concentration of hard component and a water temperature of the makeup water are respectively measured by a hard component sensor 57 and a water temperature sensor 58 between the water softening device 53 and the deoxidizing device 56, the resin unit is switched to another resin unit when the measured concentration of hard component is over a prescribed concentration, and the makeup water is passed through the deoxidizing device 56 at a flow rate less than the prescribed flow rate X when the measured water temperature is lower than a prescribed temperature. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for supplying make-up water for boiler feed water, and in particular, stores the make-up water as a boiler feed water in a water storage tank, supplies the boiler feed water from the water storage tank to a steam boiler and heats the steam generated by the load device The present invention relates to a method for supplying make-up water to a water storage tank in a steam boiler apparatus used in the above.

  2. Description of the Related Art A steam boiler apparatus is known in which makeup water derived from raw water such as tap water and groundwater is stored in a water storage tank as boiler feed water, and the boiler feed water from the water storage tank is supplied to a steam boiler. For example, in the case of a once-through boiler, the steam boiler used in this steam boiler apparatus includes a large number of heat transfer tubes for generating steam by heating boiler water from boiler feed water. Since this heat transfer tube is formed using a non-passivated metal such as carbon steel, corrosion is likely to occur due to the influence of dissolved oxygen contained in the boiler feed water. Corrosion due to the effect of dissolved oxygen is usually porous corrosion (pitting corrosion) that progresses in the thickness direction of the heat transfer tube, and the rate of progress is high, resulting in fatal destruction such as opening of the heat transfer tube. Often brought in a short time. In addition, the heat transfer tube easily adheres to the hardness contained in the boiler feed water, that is, the scale generated by calcium ions or magnesium ions. This scale lowers the thermal conductivity of the heat transfer tube and hinders smooth heating of boiler water.

  Therefore, in a steam boiler device, in order to suppress corrosion and scale generation in the steam boiler and to ensure continuous and stable operation of the steam boiler device, the make-up water supplied to the water storage tank is usually softened and removed. Oxygen treatment is performed (for example, see Patent Document 1 and Patent Document 2). Here, the softening of the makeup water is performed by replacing calcium ions and magnesium ions in the makeup water with sodium ions by treatment of the makeup water using a sodium-type cation exchange resin. On the other hand, the deoxygenation treatment is performed, for example, by passing makeup water through a gas separation membrane.

JP 2003-120904 A, paragraph [0005]. JP 2004-19970 A, paragraph [0009].

  However, since the raw water used as makeup water is tap water or groundwater as described above, the water quality varies depending on geological factors. For example, the hardness concentration of raw water may be high or low depending on the region, and is likely to fluctuate in the same region due to seasonal factors and other factors. For this reason, sodium-type cation exchange resins used for water softening are easy to break through in areas where the hardness concentration of makeup water is high, and a portion of the hardness in makeup water can be removed in a relatively short time. There is a possibility of disappearing. Moreover, since the dissolved oxygen concentration of raw | natural water is influenced by temperature, in the environment where the temperature of raw | natural water is easy to fluctuate, it always tends to fluctuate. In general, makeup water tends to increase the concentration of dissolved oxygen when the water temperature decreases. Therefore, the gas separation membrane is in a high-load state when the temperature of makeup water decreases, and the dissolved oxygen in the makeup water permeates. It becomes easy.

  An object of the present invention is to increase the certainty of softening and deoxygenation of make-up water when supplying make-up water to a water storage tank for supplying boiler feed water to a steam boiler device.

  The present invention relates to a steam boiler apparatus in which makeup water is stored in a water storage tank as boiler feed water, and steam generated by supplying the boiler feed water from the water storage tank to the steam boiler and heating is used in the load device. The present invention relates to a method for supplying makeup water. In this supply method, one resin unit is selected from a resin unit group including at least two resin units each having a sodium type cation exchange resin, and the selected resin unit is supplied from makeup water by ion exchange with a sodium type ion exchange resin. Step A for removing the hardness component, Step B for passing the makeup water from which the hardness component has been removed at a predetermined flow rate through the deoxygenator, and removing the dissolved oxygen contained in the makeup water, and the makeup water having passed the deoxygenator Between the step A and the step B, and the step D for measuring the hardness concentration and the water temperature of the makeup water. Here, when the hardness concentration measured in the step D exceeds a predetermined concentration, another resin unit is selected in the resin unit group to execute the step A, and the water temperature measured in the step D is lower than the predetermined temperature. In step B, make-up water is passed through the deoxidizer at a flow rate lower than the predetermined flow rate.

  In such a boiler water supply water supply method, the hardness of the make-up water is removed in step A, and then dissolved oxygen is removed in step B, and then supplied to the water storage tank in step C and stored. The In this series of processes, in the process D, the concentration of hardness and the water temperature are measured between the process A and the process B in the process D.

  Here, when the measured hardness concentration exceeds a predetermined concentration, that is, when there is a hardness leak in the makeup water from the resin unit due to breakthrough of the sodium-type cation exchange resin, etc., the resin unit Switch the resin unit to another in the group and execute step A. As a result, in the replenishing water thereafter, the hardness component is removed by the sodium cation exchange resin of the other resin unit in the process A, and the hardness component is more reliably removed. On the other hand, when the measured temperature of the makeup water is lower than the predetermined temperature, that is, when the dissolved oxygen concentration in the makeup water is increased, the flow rate of the makeup water is set to be lower than the predetermined flow rate in Step B. As a result, the make-up water has a longer residence time in the deoxygenation device, and dissolved oxygen is more reliably removed.

  In this supply method, for example, while performing steps A, B, C, and D, the sodium type cation exchange resin of the resin unit other than the resin unit selected for step A is regenerated in the resin unit group. In this way, the resin unit other than the resin unit used for the process A can be set to a state in which the ion exchange capacity of the sodium ion exchange resin is enhanced, so that the hardness component measured in the process D When the concentration exceeds a predetermined concentration, the resin unit can be smoothly switched to another in step A.

  In addition, the deoxygenation device used in this supply method is usually of a type in which the retention time of the make-up water becomes long when the flow rate of the make-up water is lowered, for example, a type in which make-up water is passed through the gas separation membrane. One type selected from the group consisting of: a type that allows makeup water to pass under a reduced pressure environment, and a type that allows makeup water to pass under a heating environment.

  The steam boiler device to which this supply method can be applied may have a condensate path extending from the load device for collecting the condensate obtained by condensing the steam to the water storage tank. In this case, according to the supply method of the present invention, boiler feed water with a small amount of dissolved oxygen can be supplied to the steam boiler, so that corrosion of the condensate path can also be effectively suppressed.

  Since the supply method for boiler feed water according to the present invention includes the above-described steps, the supply water to the water storage tank in the steam boiler apparatus is improved in the reliability of softening and deoxygenation of the makeup water. be able to.

  With reference to FIG. 1, the steam boiler apparatus which can implement the supply method of the supplementary water for boiler feed water which concerns on one Embodiment of this invention is demonstrated. In FIG. 1, a steam boiler device 1 is for supplying steam to a load device 2 that is a steam using facility such as a heat exchanger, a steam kettle, a reboiler, or an autoclave, and includes a water supply device 10 and a steam boiler 20. And a condensate path 30 is mainly provided.

  The water supply device 10 is for supplying boiler feed water to the steam boiler 20, and includes a storage tank 40 for storing boiler supply water, and a supply path 50 for supplying makeup water used as boiler supply water to the storage tank 40. And mainly. The water storage tank 40 has a water supply path 41 extending from the bottom to the steam boiler 20. The water supply path 41 communicates with the steam boiler 20, and has a water supply pump 42 for sending the boiler feed water stored in the water storage tank 40 to the steam boiler 20.

  The supply path 50 has a water injection path 51. This water injection channel 51 is for supplying makeup water to a water storage tank 40 from a raw water tank (not shown) in which raw water supplied from a water source such as tap water, industrial water or groundwater is stored. A pretreatment device 52, a water softening device 53, a preliminary filtration device 54, a filtration treatment device 55, and a deoxygenation device 56 are provided in this order toward the tank 40. In addition, a hardness sensor 57 and a water temperature sensor 58 are arranged between the filtration device 55 and the deoxygenation device 56 in the water injection channel 51, and the flow rate is measured on the deoxygenation device 56 side of these sensors 57 and 58. A control valve 59 is provided. Further, the water injection channel 51 has a control device 60 for controlling the water softening device 53 and the flow rate adjustment valve 59.

  The pretreatment device 52 is a filtration device filled with activated carbon capable of adsorbing an oxidizing agent such as sodium hypochlorite dissolved in makeup water from the raw water tank, and oxidizes sodium hypochlorite from raw water. It is for removing an agent.

  As shown in FIG. 2, the water softening device 53 includes a resin unit group 61 including two resin units, a first resin unit 61a and a second resin unit 61b. In the water softening device 53, the water injection path 51 is branched into two paths, a first path 51a and a second path 51b, by the switching valve 62, and the first path 51a communicates with the first resin unit 61a. The second path 51b communicates with the second resin unit 61b. The first path 51 a and the second path 51 b merge together at the downstream side of the resin units 61 a and 61 b and extend to the preliminary filtration device 54.

  Here, each resin unit 61a, 61b is filled with sodium-type cation exchange resin. The sodium-type cation exchange resin is for replacing the hardness component contained in the makeup water treated in the pretreatment device 52, that is, calcium ions and magnesium ions with sodium ions, and converting the makeup water into softened water. is there. The switching valve 62 is an electromagnetic valve and is used to select the water injection path 51 as either the first path 51a or the second path 51b.

  In the water softening device 53, the first resin unit 61a and the second resin unit 61b are detachable, and the sodium-type cation exchange resin can be exchanged.

  The preliminary filtration device 54 is for removing solid substances such as suspended substances and dust mixed in the makeup water softened by the water softening device 53, and for filtering and separating the solid matter. A filter medium (not shown) such as a wind filter, a pleated filter or a mesh filter is provided.

  The filtration device 55 is for removing various dissolved components, that is, various ions and low molecular weight substances contained in the makeup water processed in the preliminary filtration device 54, and filters and separates the dissolved components. A filtration membrane (not shown) is provided. The filtration membrane used here is a nanofiltration membrane. The nanofiltration membrane is formed using a synthetic polymer such as a polyamide-based or polyether-based material that is generally referred to as an NF (Nanofiltration) membrane, and is an AMST (Association of Membrane Separation Technology) standard AMST- 002, “The molecular weight range of the separation target substance used at an operating pressure of 1.5 MPa and showing a removal rate of 90% or more shows 200 to 1,000, and the sodium chloride concentration of the test solution is 500 to 2,000 mg / liter. , A membrane having a sodium chloride removal rate of 5% or more and less than 93% under an evaluation condition of an operating pressure of 0.3 to 1.5 MPa ”. Incidentally, nanofiltration membranes are commercially available from various companies and can be easily obtained.

  In the filtration device 55, the nanofiltration membrane is used in various shapes. That is, the nanofiltration membrane is used in various shapes such as a flat membrane type, a hollow fiber membrane type, a tubular type, and a Nomoris type.

  The deoxygenation device 56 is for removing dissolved oxygen in the make-up water treated in the filtration device 55. The deoxygenation device 56 is of a type in which the deoxygenation capacity increases as the residence time of the make-up water that passes through increases. A type that removes dissolved oxygen by passing water through a gas separation membrane (for example, a type that removes dissolved oxygen by passing makeup water through the inside while decompressing the outside of the hollow fiber gas separation membrane), Various types of known types such as a type in which make-up water is passed under a reduced pressure environment to remove dissolved oxygen, or a type in which make-up water is passed through while heating to remove dissolved oxygen are used. .

  The hardness component sensor 57 is for measuring the concentration of hardness component contained in the makeup water from the filtration device 55, and is, for example, a colorimetric type, electrode type or titration type sensor. On the other hand, the water temperature sensor 58 is for measuring the temperature of the makeup water supplied from the filtration device 55, and is, for example, a sensor such as a thermistor, a thermocouple, or a resistance temperature detector.

  The flow rate adjustment valve 59 is an electromagnetic valve, and can arbitrarily adjust the flow rate of makeup water flowing from the filtration device 55 to the deoxygenation device 56.

  The control device 60 is for controlling the switching valve 62 and the flow rate adjusting valve 59 based on the hardness information and the water temperature information measured by the hardness sensor 57 and the water temperature sensor 58, respectively.

  The steam boiler 20 is a once-through boiler, and as shown in FIG. 3, an annular storage portion 21 capable of storing boiler feed water supplied from a water supply path 41, and a large number of heat transfer tubes 22 rising from the storage portion 21 (FIG. 3). Only two are shown), and mainly includes an annular header 23 provided at the upper end of the heat transfer tube 22, a steam supply passage 24 extending from the header 23 to the load device 2, and a combustion device 25 such as a burner. The combustion device 25 can radiate combustion gas from the header 23 side toward the storage portion 21 to heat the heat transfer tube 22.

  The heat transfer tube 22 is formed using a non-passivated metal. A non-passivated metal refers to a metal that does not passivate naturally in a neutral aqueous solution, and is usually a metal other than stainless steel, titanium, aluminum, chromium, nickel, zirconium, and the like. Specifically, carbon steel, cast iron, copper, copper alloy, and the like. Carbon steel may be passivated in the presence of a high concentration of chromate ions even in a neutral aqueous solution. This passivation is due to the influence of chromate ions, and the neutral aqueous solution. It's hard to say that it's a natural passivation inside. Therefore, carbon steel belongs to the category of non-passivated metals here. In addition, copper and copper alloys are considered to be metals that are unlikely to corrode due to the influence of moisture due to their noble position in the electrochemical column (emf series), but they are naturally passive in neutral aqueous solutions. Since it does not become a non-passivated metal, it belongs to the category of non-passivated metals.

  The condensate path 30 is formed using a non-passivated metal like the heat transfer tube 22, and extends from the load device 2 to the water storage tank 40. In addition, the condensate path 30 has a steam trap 31. The steam trap 31 is for separating steam and water. The tip of the condensate passage 30 is preferably disposed in the boiler feed water in order to prevent air from being normally involved in the boiler feed water stored in the water storage tank 40. It is particularly preferable that they are arranged in the vicinity.

  Next, the operation method of the above steam boiler apparatus 1 will be described while touching the supply method of boiler water supply water. Here, in the initial state, the control device 60 switches the switching valve 62 to the first path 51a side, and the flow rate of makeup water flowing from the filtration device 55 to the deoxygenation device 56 in the water injection path 51 is a predetermined flow rate. Assume that the flow control valve 59 is set to be X.

  During operation of the steam boiler device 1, makeup water is supplied from the raw water tank to the water storage tank 40 through the water injection channel 51, and this makeup water is stored in the water storage tank 40 as boiler feed water.

  At this time, the makeup water from the raw water tank is first supplied to the pretreatment device 52 through the water injection channel 51, where the oxidant is adsorbed and removed by the activated carbon. Subsequently, makeup water from the pretreatment device 52 flows to the water softening device 53. The makeup water that has flowed to the water softening device 53 flows to the first path 51a via the switching valve 62 and passes through the first resin unit 61a. Thereby, the hardness component contained in the makeup water is ion-exchanged with sodium ions by the sodium-type cation exchange resin, and becomes softened water from which the hardness component has been removed.

  Incidentally, the sodium-type cation exchange resin used in the water softening device 53 is easily deteriorated due to the influence of the oxidizing agent, and the ion exchange capacity tends to be lowered. In this embodiment, the makeup water supplied to the water softening device 53 is Since the oxidizing agent is removed in the pretreatment device 52, the sodium-type cation exchange resin is hardly deteriorated. Therefore, the water softening device 53 can soften the makeup water stably over a long period of time.

The make-up water that has become softened in the water softening device 53 is then further filtered in the filtration processing device 55 after solid matter such as suspended solids and dust is removed by filtration in the preliminary filtration device 54. The In the filtration device 55, the makeup water from the preliminary filtration device 54 is filtered by the nanofiltration membrane. As a result, the components that cause corrosion of the steam boiler 20 such as the heat transfer tube 22 and the components that cause corrosion of the condensate path 30 are removed. Here, the components that cause corrosion of the steam boiler 20 are mainly chloride ions (Cl ⁻ ) and sulfate ions (SO ₄ ²⁻ ). In addition, a component that causes corrosion of the condensate path 30 is a salt in which makeup water is converted to a sodium salt by water softening in the water softening device 53, for example, an alkaline component such as sodium hydrogen carbonate or sodium carbonate. Since these alkali components are decomposed by heating in the steam boiler 20 to generate carbon dioxide gas, they can cause corrosion of the condensate passage 30. In the following description, components that cause corrosion of the steam boiler 20 and components that cause corrosion of the condensate passage 30 may be collectively referred to as “corrosion promoting components”.

  On the other hand, most (usually 40% or more) of silica derived from raw water contained in the makeup water from the water softening device 53 passes through the nanofiltration membrane.

  Incidentally, since the oxidizing water is removed in the pretreatment device 52 from the supplementary water from the preliminary filtration device 54 and the solid matter is removed in the preliminary filtration device 54, the nanofiltration membrane of the filtration treatment device 55 is Deterioration due to oxidation hardly occurs, and clogging hardly occurs. Therefore, the filtration device 55 can stably remove the above-described corrosion promoting components from the makeup water over a long period of time.

  The makeup water that has been filtered in the filtering device 55 is then deoxygenated in the deoxygenating device 56. As a result, the makeup water removes dissolved oxygen that promotes corrosion (particularly pitting corrosion) of the heat transfer tubes 22 and the like of the steam boiler 20 and corrosion of the condensate passage 30.

  As a result, the water supply tank 40 stores the makeup water treated in the deoxygenation device 56, that is, softened water that has been deoxygenated and from which the corrosion promoting component has been removed, as boiler feed water. This boiler feedwater contains silica that has passed through the nanofiltration membrane of the filtration device 55.

  When the water supply pump 42 is operated in a state where makeup water is stored in the water storage tank 40, the makeup water stored in the water storage tank 40, that is, boiler water supply, is supplied to the steam boiler 20 through the water supply path 41. Boiler feed water supplied to the steam boiler 20 is stored as boiler water in the storage unit 21. The boiler water rises in the heat transfer tubes 22 while being heated by the combustion device 25 through the heat transfer tubes 22 and gradually becomes steam. Then, the steam generated in each heat transfer tube 22 is collected in the header 23 and supplied to the load device 2 through the steam supply path 24.

  The steam supplied to the load device 2 flows through the load device 2 to the condensate passage 30 where it loses latent heat and partly changes to condensed water, and the steam and water are separated in the steam trap 31 so that the temperature is high. It becomes the condensate. The condensate thus generated is collected into the water storage tank 40 through the condensate path 30 and mixed with the makeup water stored in the water storage tank 40 to be reused as boiler feed water. At this time, since the boiler feed water stored in the water storage tank 40 is heated by the high-temperature condensate, the heating burden on the steam boiler 20 is reduced. Therefore, the steam boiler apparatus 1 can suppress the fuel cost for operating the steam boiler 20, and can be operated economically.

  During operation of the steam boiler device 1 as described above, boiler feed water stored as boiler water in the steam boiler 20 contacts the inner surface of the heat transfer tube 22 and the like. In general, the heat transfer tube 22 or the like made of a non-passivated metal is easily corroded under the influence of boiler water. In this embodiment, however, ion components such as chloride ions and sulfate ions and dissolved ions are present in the boiler feed water. Since oxygen is removed, the steam boiler 20 is unlikely to corrode the heat transfer tubes 22 and the like. Moreover, since the silica contained in boiler feed water forms a film | membrane in the storage part 21 of the steam boiler 20, and the internal surface of the heat exchanger tube 22, the corrosion inhibitory effect with respect to the steam boiler 20 can be heightened. Furthermore, since the alkaline component as described above is removed from the boiler water, it is difficult to generate carbon dioxide gas when heated. For this reason, in this steam boiler apparatus 1, corrosion of the condensate path 30 by the influence of a carbon dioxide gas is also suppressed. That is, since the steam boiler apparatus 1 of this embodiment can remove the corrosion inhibitory component and dissolved oxygen in the boiler feed water, the steam boiler 20 and the condensate path 30 are not dependent on the addition of chemicals to the boiler feed water. Both corrosions can be suppressed.

  Moreover, in this steam boiler apparatus 1, since the boiler feed water supplied to the steam boiler 20 is softened water from which the hardness has been removed, the heat transfer tube 22 is also restrained from adhering to the scale.

  During operation of the steam boiler device 1, the hardness component sensor 57 and the water temperature sensor 58 always measure the hardness component concentration and the water temperature of makeup water flowing from the filtration device 55 to the deoxygenation device 56, respectively. The purpose of measuring the hardness concentration of the makeup water with the hardness sensor 57 is to confirm the treatment status of the makeup water in the water softening device 53, that is, the water softening status. On the other hand, the purpose of measuring the temperature of the makeup water with the water temperature sensor 58 is to predict the amount of dissolved oxygen contained in the makeup water. In the makeup water, the lower the water temperature, the higher the solubility of dissolved oxygen and the more dissolved oxygen amount. Therefore, the tendency of the dissolved oxygen amount can be predicted by the water temperature.

  When the hardness concentration of the makeup water measured by the hardness sensor 57 exceeds a predetermined concentration Y set in advance, the breakthrough of the sodium-type cation exchange resin (ion exchange capacity) in the first resin unit 61a of the water softening device 53 Therefore, the control device 60 operates the switching valve 62 to switch the water injection path 51 from the first path 51a to the second path 51b. Thereby, the makeup water from the pretreatment device 52 flows to the second path 51b and is supplied to the second resin unit 61b, and is subjected to ion exchange treatment with the sodium-type cation exchange resin.

  While the water injection channel 51 is switched to the second channel 51b, the first resin unit 61a is removed from the water softening device 32, and the sodium-type cation exchange resin is replaced with a new one. In this way, when the hardness concentration of make-up water measured by the hardness sensor 57 exceeds the predetermined concentration Y set in advance when the second resin unit 61b is used, the controller 60 causes the water injection channel 51 to be set. By switching from the second path 51b to the first path 51a, the first resin unit 61a in which the sodium-type ion exchange resin has been replaced can be subjected to ion exchange treatment of the makeup water. As described above, if the sodium-type cation exchange resin filled in the resin unit other than the resin unit selected in the resin unit group 61 (that is, the resin unit in use) is replaced while it is not in use, makeup water is supplied. When the hardness component concentration exceeds a predetermined concentration Y set in advance, the resin unit can be quickly changed to the other one by switching the switching valve 62. Therefore, the makeup water is softened more reliably in the water softening device 32. As a result, in the water storage tank 40, make-up water with a low hardness is stored as boiler feed water, so that the steam boiler device 20 can effectively suppress scale generation.

  On the other hand, when the water temperature of the make-up water measured by the water temperature sensor 58 becomes lower than the predetermined water temperature Z, the amount of dissolved oxygen in the make-up water is increased, so that the deoxidation process in the deoxygenation device 56 is expected to be insufficient. Therefore, the control device 60 controls the flow rate adjusting valve 59 to reduce the flow rate of the makeup water flowing from the filtration processing device 55 to the deoxygenation device 56 to be less than the predetermined flow rate X. As a result, the deoxygenation device 56 has a reduced supply flow rate of the make-up water and a longer stay time of the make-up water, so that the ability to remove dissolved oxygen in the make-up water is increased. Therefore, even if the temperature of the makeup water is lowered, the storage tank 40 is supplied with the makeup water with a small amount of dissolved oxygen.

  In addition, when the water temperature of the makeup water measured by the water temperature sensor 58 returns to the predetermined water temperature Z or higher, the control device 60 controls the flow rate adjustment valve 59 and supplies the makeup water flowing from the filtration processing device 55 to the deoxygenation device 56. The flow rate is returned to the predetermined flow rate X.

  As a result, in the water storage tank 40, the makeup water from which dissolved oxygen has been removed more reliably is stored as boiler feed water. Therefore, the steam boiler device 1 is subject to corrosion (particularly pitting corrosion) of the steam boiler 20. Is more effectively suppressed, and corrosion of the condensate passage 30 is also more effectively suppressed.

Modification (1) In the above-described embodiment, the water softening device 53 replaces the sodium-type cation exchange resin of the resin unit that is not in use. When not in use, it can be regenerated while attached to the water softening device 53.

  In this case, a sodium chloride aqueous solution preparation device is provided in the water softening device 53, and the sodium chloride aqueous solution is supplied from this preparation device into an unused resin unit. Thereby, the hardness component adhering to the sodium-type cation exchange resin is again exchanged with sodium ions, and the sodium-type cation exchange resin has an increased ion exchange capacity with the hardness component.

(2) In the above embodiment, the water softening device 53 uses the resin unit group 61 having the two resin units 61a and 61b, but the resin unit group 61 has three or more resin units. May be.

(3) In the above-described embodiment, the hardness component sensor 57 and the water temperature sensor 58 are arranged between the filtration device 55 and the deoxygenation device 56, and the hardness component concentration and the water temperature of the makeup water are measured. The hardness of the make-up water and the water temperature can also be measured between the water softening device 53 and the preliminary filtration device 54 or between the preliminary filtration device 54 and the filtration treatment device 55. However, in order to increase the deoxygenation capacity in the deoxygenation device 56, it is preferable to measure the temperature of the makeup water immediately before the deoxygenation device 56 as in the above-described embodiment.

(4) In the above-described embodiment, the nanofiltration membrane is used in the filtration device 55. However, the nanofiltration membrane can be changed to a reverse osmosis membrane. The reverse osmosis membrane is formed using a synthetic polymer such as polyamide, generally called RO (Reverse Osmosis) membrane. In AMST-002 of AMST (Association of Membrane Separation Technology) standard, A membrane with a sodium chloride concentration of 500 to 2,000 mg / liter and an operating pressure of 0.5 to 3.0 MPa under a sodium chloride removal rate of 93% or more ” It is distinguished from. Incidentally, reverse osmosis membranes are commercially available from various companies and can be easily obtained.

  Reverse osmosis membranes are used in various shapes, similar to nanofiltration membranes. That is, the reverse osmosis membrane is used in various shapes such as a flat membrane type, a hollow fiber membrane type, a tubular type, and a Nomoris type.

  Since the reverse osmosis membrane used in the filtration treatment device 55 can remove the corrosion promoting component contained in the makeup water as in the case of the nanofiltration membrane, in the steam boiler device 1, the heat transfer tube 22 and the condensate of the steam boiler 20 are used. Corrosion of the path 30 can be effectively suppressed. In particular, the reverse osmosis membrane is superior to the nanofiltration membrane in the ability to remove sodium bicarbonate, sodium carbonate, and the like, that is, the alkali component that causes carbon dioxide generation, contained in the makeup water. Generation | occurrence | production of a carbon dioxide gas can be prevented more effectively, and the corrosion of the condensate path | route 30 can be suppressed more effectively.

(5) The filtration device 55 may include both the nanofiltration membrane 55a and the reverse osmosis membrane 55b as shown in FIG. In this case, it is preferable that the filtration device 55 is set so that the makeup water is filtered by the reverse osmosis membrane 55b after being filtered by the nanofiltration membrane 55a. Such a filtration processing device 55 removes the corrosion promoting component in the makeup water by both the nanofiltration membrane 55a and the reverse osmosis membrane 55b, and the removal capability of the corrosion promoting component is enhanced. Corrosion of the heat transfer tube 22 and the condensate passage 30 of the steam boiler 20 can be further effectively suppressed.

(6) In each of the above-described embodiments, the filtration device 55 is used to suppress corrosion caused by the corrosion promoting component. However, various known chemicals may be used to inhibit corrosion caused by the corrosion promoting component. It can also be added to make-up water, boiler feed water or boiler water.

(7) In the above-described embodiments, a case where a once-through boiler is used as the steam boiler 20 is taken as an example, but the present invention can be similarly implemented even when another type of steam boiler 20 is used. it can.

1 is a schematic diagram of a steam boiler device that can implement a method for supplying makeup water according to an embodiment of the present invention. Schematic of the water softening device used in the steam boiler device. The partial cross section schematic of the steam boiler used in the said steam boiler apparatus. Schematic of the filtration processing apparatus of the other form used in the said steam boiler apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steam boiler apparatus 2 Loading apparatus 20 Steam boiler 30 Condensate path 40 Reservoir tank 50 Replenishment path 53 Softening apparatus 56 Deoxygenation apparatus 57 Hardness sensor 58 Water temperature sensor 59 Flow control valve 61 Resin unit group 61a First resin unit 61b 1st Two resin unit

Claims (4)

In a steam boiler apparatus that uses steam generated by storing makeup water in a storage tank as boiler feed water and supplying the boiler feed water from the storage tank to a steam boiler for heating in a load device, the replenishment to the water storage tank A method for supplying water,
One resin unit is selected from a resin unit group including at least two resin units having a sodium type cation exchange resin, and the hardness of the replenished water is determined by ion exchange of the selected resin unit with the sodium type ion exchange resin. Removing step A;
Passing the makeup water from which the hardness has been removed through a deoxygenating device at a predetermined flow rate, and removing dissolved oxygen contained in the makeup water; and
Supplying the makeup water that has passed through the deoxygenation device to the water storage tank;
Between the process A and the process B, including a process D for measuring the hardness concentration and the water temperature of the makeup water,
When the hardness concentration measured in step D exceeds a predetermined concentration, another resin unit is selected in the resin unit group and step A is executed, and the water temperature measured in step D is less than a predetermined temperature. When in step B, the makeup water is passed through the deoxygenation device at a flow rate less than the predetermined flow rate,
Supply method of makeup water for boiler water supply.   The sodium-type cation exchange resin of the resin unit other than the resin unit selected for the step A is regenerated in the resin unit group while performing the steps A, B, C, and D. Supply method of makeup water for boiler water supply.   The deoxygenation device includes a type that allows the makeup water to pass through a gas separation membrane, a type that allows the makeup water to pass under a reduced pressure environment, and a type that allows the makeup water to pass under a heating environment. The method for supplying boiler water supply water according to claim 1 or 2, wherein the supply water is of one type selected from the group consisting of: The said steam boiler apparatus has a condensate path | route extended from the said load apparatus for collect | recovering the condensate obtained by the said steam condensing to the said storage tank. To supply makeup water for boilers.

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