JP2012215319A - Steam generating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam generating system of high efficiency by reducing temperature difference in pumping up by a heat pump.SOLUTION: This steam generating system includes a first heat pump 2 of single stage or multiple stages, and a second heat pump 3 having the number of stages more than that of the first heat pump 2. Heat source fluid is successively passed through an evaporator 7 of the lowermost stage of the first heat pump 2 and an evaporator 11B of the lowermost stage of the second heat pump 3. The water is heated to generate steam in a condenser 5 of the uppermost stage of the first heat pump 2 and a condenser 9A of the uppermost stage of the second heat pump 3.

Description

  The present invention relates to a steam generation system that generates steam using a heat pump.

  Conventionally, as disclosed in Patent Document 1 below, there is known a heat pump that draws heat from waste water or the like in an evaporator and heats water in a condenser to generate steam.

  Further, as disclosed in Patent Document 2 below, the heat pump is configured in a plurality of upper and lower stages, and through a heat exchanger (a condenser of the lower heat pump and an evaporator of the upper heat pump) that connects the upper and lower heat pumps. A system has also been proposed in which the feed water is heated and steam is extracted from the condenser of the uppermost heat pump.

  Furthermore, as disclosed in Patent Document 3 below, a device has also been proposed in which heat pumps are installed in parallel on the left and right sides, and water is passed through the condensers of each heat pump in order to obtain high-temperature water.

JP 58-40451 (Fig. 2) JP 2006-348876 A (FIGS. 1 and 2) Japanese Utility Model Publication No. 60-23669 (Fig. 2)

  However, just using a single-stage heat pump as in the invention described in Patent Document 1, the temperature difference that pumps heat, that is, the temperature difference between the evaporator side and the condenser side is large, and the efficiency of the heat pump is poor.

  Further, as in the invention described in Patent Document 2, even if heat pumps are simply installed in a plurality of upper and lower stages, heat is drawn only from the lowermost evaporator, as in the invention described in Patent Document 1. The temperature difference to be pumped when viewed from the whole heat pump is large, and there is a limit to improving the efficiency of the heat pump.

  Moreover, even if the heat pumps are installed in parallel on the left and right as in the invention described in Patent Document 3, the left and right heat pumps have the same configuration, and heat is drawn only from the lowermost evaporator. Similar to the described invention, the temperature difference to be pumped is large, and there is a limit to improving the efficiency of the heat pump.

  Furthermore, when the heat source fluid is warm water or exhaust gas, etc., and the temperature itself decreases while giving heat (sensible heat) to the heat pump, simply passing the heat source fluid through the heat pumps installed in parallel with the same configuration on the left and right In this heat pump, since the temperature of the heat source fluid is lowered, it is necessary to consider this.

  The problem to be solved by the present invention is to reduce the pumping temperature difference when viewed from the whole system, thereby improving the efficiency of the system. Moreover, when a heat source fluid gives sensible heat to a heat pump, it aims at providing the steam generation system which can respond also to the temperature fall accompanying it.

  The present invention has been made to solve the above problems, and the invention according to claim 1 includes a single-stage or multiple-stage first heat pump, and a second heat pump having a larger number of stages than the first heat pump. The heat source fluid is sequentially passed through the lowermost evaporator of the first heat pump and the lowermost evaporator of the second heat pump, and the uppermost condenser of the first heat pump and the second heat pump. In the uppermost condenser, the steam generation system is characterized in that steam is generated by heating water.

  According to the first aspect of the present invention, heat is pumped from the lowermost evaporator of the first heat pump and the lowermost evaporator of the second heat pump, and the uppermost condenser of the first heat pump; Steam can be generated in the uppermost condenser of the two heat pump. At this time, the heat source fluid passes through the lowermost evaporator of the first heat pump and then passes through the lowermost evaporator of the second heat pump. And by keeping the number of stages of the second heat pump more than that of the first heat pump, the second heat pump covers the amount of the heat source fluid cooled in the first heat pump, and also from the heat source fluid after passing through the first heat pump. You can pump up the heat again. Further, in the first heat pump, the temperature difference to be pumped can be reduced, the power of the compressor can be reduced by that amount, and the efficiency of the steam generation system can be improved.

  According to a second aspect of the present invention, the first heat pump includes a single-stage heat pump, the second heat pump includes a two-stage heat pump, the evaporator of the first heat pump, and the second heat pump. Heat is drawn from a heat source fluid that is sequentially passed to a lower evaporator, and water is heated to generate steam in the upper condenser of the second heat pump and the condenser of the first heat pump. The steam generation system according to claim 1.

  According to the second aspect of the present invention, at least a single-stage heat pump and a two-stage heat pump are provided, and the heat source fluid is sequentially passed through the lowermost evaporators to generate steam in the uppermost condensers. Can be made.

  According to a third aspect of the present invention, the second heat pump includes a plurality of heat pumps installed in parallel, and the heat source fluids are sequentially passed through the lowermost evaporators, and the heat source fluids. The steam generation system according to claim 1, wherein the steam generation system is configured such that the number of stages increases in order of passage of water, and steam is generated by heating water in each of the uppermost condensers.

  According to invention of Claim 3, when it sees in the whole steam generation system, it will be provided with three or more heat pumps comprised by a single stage or multiple stages. The plurality of heat pumps are configured so that the heat source fluid is sequentially passed through the lowermost evaporators, and the number of stages is increased in the order in which the heat source fluids are passed, and water is heated in each uppermost condenser. Steam can be generated.

  According to a fourth aspect of the present invention, in the plurality of heat pumps constituting the second heat pump, the heat source fluid is sequentially passed through each lowermost evaporator, and the number of stages is increased step by step in the order in which the heat source fluid is passed. The steam generation system according to claim 3, wherein the steam generation system is configured to generate steam by heating water in each uppermost condenser.

  According to the fourth aspect of the present invention, it is possible to efficiently generate heat and generate steam with a simple configuration by increasing the number of stages one by one in the order in which the heat source fluid is passed.

  The invention according to claim 5 is characterized in that in the uppermost condenser of the first heat pump and the uppermost condenser of the second heat pump, water is heated to generate steam of the same pressure. The steam generation system according to any one of claims 1 to 4.

  According to the fifth aspect of the present invention, steam having the same pressure can be generated in the uppermost condenser of the first heat pump and the uppermost condenser of the second heat pump.

In the invention according to claim 6, when the first heat pump and / or the second heat pump has a plurality of stages, the heat pumps of adjacent stages are connected to each other by any one of the following relationships (a) to (c). The steam generation system according to any one of claims 1 to 5, wherein:
(A) An indirect heat exchanger that receives the refrigerant from the compressor of the lower heat pump and the refrigerant from the expansion valve of the upper heat pump and exchanges heat without mixing the two refrigerants is provided. It is a condenser and an evaporator of the upper heat pump.
(B) An intermediate cooler that receives the refrigerant from the compressor of the lower heat pump and the refrigerant from the expansion valve of the upper heat pump and exchanges heat by bringing both refrigerants into direct contact with each other. It is a condenser and an evaporator of the upper heat pump.
(C) The refrigerant from the compressor of the lower heat pump and the refrigerant from the expansion valve of the upper heat pump are received, the two refrigerants are brought into direct contact and heat exchange is performed, and the expansion valve An intermediate cooler that exchanges heat without mixing with the refrigerant supplied to the expansion valve of the lower heat pump without passing through the intermediate heat exchanger is provided, and this intermediate cooler is a condenser of the lower heat pump and an evaporator of the upper heat pump.

  According to the invention described in claim 6, the first heat pump and / or the second heat pump can be configured in a plurality of stages, and the heat pumps of adjacent stages are connected by an indirect heat exchanger or an intercooler, A steam generation system can be configured.

Invention of Claim 7 is equipped with any one or more sub heat exchangers among the following (a)-(f), and the uppermost stage condenser of said 2nd heat pump, and 1st sub heat exchange The first sub heat exchanger when the heat exchanger is installed, the uppermost condenser of the first heat pump, and the second sub heat exchanger when the second sub heat exchanger is installed, When the first sub heat exchanger and / or the second sub heat exchanger are installed, the sub heat exchanger is placed before the uppermost condenser of each heat pump. When the lowermost evaporator of the first heat pump and the third sub heat exchanger are installed, the third sub heat exchanger and the lowermost evaporation of the second heat pump are set. And heat to the fourth sub heat exchanger, if installed. The flow order of the fluid, a steam generating system according to any one of claims 1 to 6, characterized in that the bottom of the evaporator of the second heat pump is set to be later.
(A) A first sub heat exchanger of refrigerant and water from the uppermost condenser of the second heat pump to the expansion valve.
(B) A second sub heat exchanger of refrigerant and water from the uppermost condenser of the first heat pump to the expansion valve.
(C) A third sub heat exchanger for the refrigerant and the heat source fluid from the lowermost evaporator of the first heat pump to the compressor.
(D) A fourth sub heat exchanger for the refrigerant and the heat source fluid from the lowermost evaporator of the second heat pump to the compressor.
(E) In the case where the second heat pump has a plurality of stages, in the case of indirect heat exchange between the refrigerants of the adjacent heat pumps, the refrigerant from the compressor of the lower heat pump to the condenser and the evaporator of the upper heat pump to the compressor The fifth sub heat exchanger with refrigerant to.
(F) In the case where the first heat pump has a plurality of stages, in the case of indirect heat exchange between the refrigerants of the adjacent heat pumps, the refrigerant from the compressor of the lower heat pump to the condenser and the evaporator of the upper heat pump to the compressor The sixth sub heat exchanger with refrigerant to.

  According to the invention of claim 7, the first sub heat exchanger is a refrigerant subcooler, the second sub heat exchanger is a refrigerant subcooler, or the third sub heat exchanger is a refrigerant subcooler. To improve the efficiency of the steam generation system by using a superheater, making the fourth sub heat exchanger a refrigerant superheater, and installing a fifth sub heat exchanger and a sixth sub heat exchanger as appropriate Can do.

  Further, the invention according to claim 8 is the steam generation system according to any one of claims 1 to 7, wherein the heat source fluid is drain from a steam using facility.

  According to the invention described in claim 8, steam can be generated by recovering heat from the drain from the steam-using facility.

  According to the present invention, it is possible to reduce the difference in pumping temperature when viewed from the whole system, thereby improving the efficiency of the system. Further, when the heat source fluid gives sensible heat to the heat pump, it is possible to cope with a temperature drop associated therewith.

It is the schematic which shows Example 1 of the steam generation system of this invention. It is a figure which shows the distribution | circulation order of water and a vapor | steam to the 1st sub heat exchanger, the upper stage condenser of a 2nd heat pump, the 2nd sub heat exchanger, and the condenser of a 1st heat pump. It is a figure which shows the distribution | circulation order of the heat source fluid to the 3rd sub heat exchanger, the evaporator of a 1st heat pump, the 4th sub heat exchanger, and the evaporator of the lower stage of a 2nd heat pump. It is a figure which shows the relationship between a 5th sub heat exchanger and the lower condenser of a 2nd heat pump, and is a figure which shows the distribution | circulation order of the refrigerant | coolant of the lower stage of a 2nd heat pump. It is the graph which compared the coefficient of performance of the steam generation system of this invention, and a conventionally well-known two-stage heat pump. It is a TS diagram of an ideal cycle. It is a TS diagram of a conventionally known single stage heat pump (reverse Carnot cycle). It is a TS diagram of the steam generation system of a present Example. FIG. 7 shows a case where the number of stages of the heat pump is increased. It is the schematic which shows Example 2 of the steam generation system of this invention. It is the schematic which shows Example 3 of the steam generation system of this invention. It is a figure which shows the example which made the 2nd heat pump into 3 steps | paragraphs. It is a figure which shows the example which comprised the 2nd heat pump from the several heat pump installed in parallel. It is a TS diagram at the time of making the first heat pump into a single stage and the second heat pump into three stages. It is a TS diagram at the time of having a 1st heat pump as a single stage, a 2nd heat pump as 2 stages, and a 3rd heat pump as 3 stages. It is the schematic which shows an example of the steam system using the steam generation system of Example 1. FIG. It is the schematic which shows the modification of the steam system of FIG.

The steam generation system of the present invention includes a plurality of heat pumps configured by a single stage or a plurality of stages. The plurality of heat pumps are configured so that the heat source fluid is sequentially passed through each lowermost evaporator, and the number of stages is increased in order in which the heat source fluid is passed (typically, the number of stages is increased by one stage). In each uppermost condenser, water is heated to generate steam (typically steam at the same pressure).
Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing Example 1 of the steam generation system 1 of the present invention.
The steam generation system 1 of the present embodiment includes a first heat pump 2 and a second heat pump 3 in parallel.

  The first heat pump 2 is a vapor compression heat pump, and is constituted by a single-stage heat pump in this embodiment. Specifically, the first heat pump 2 is configured by sequentially connecting a compressor 4, a condenser 5, an expansion valve 6 and an evaporator 7 in an annular shape. The compressor 4 compresses the gas refrigerant to a high temperature and a high pressure. The condenser 5 condenses and liquefies the gas refrigerant from the compressor 4. Furthermore, the expansion valve 6 allows the liquid refrigerant from the condenser 5 to pass therethrough, thereby reducing the pressure and temperature of the refrigerant. The evaporator 7 evaporates the refrigerant from the expansion valve 6.

  Accordingly, in the first heat pump 2, the refrigerant takes the heat from the outside and vaporizes in the evaporator 7, while in the condenser 5, the refrigerant dissipates heat to the outside and condenses. Utilizing this, the first heat pump 2 draws up heat from the heat source fluid in the evaporator 7 and heats water in the condenser 5 to generate steam.

  The heat source fluid (the heat source of each heat pump 2, 3) is not particularly limited, but is preferably a fluid that gives sensible heat to each heat pump 2, 3, that is, a fluid that itself lowers the temperature while giving heat to each heat pump 2, 3. Used for. For example, drainage from steam using facilities, exhaust gas from boilers, etc. are used.

  In the circuit of the heat pump 2, an oil separator is installed on the outlet side of the compressor 4, a liquid receiver is installed on the outlet side of the condenser 5, or an accumulator is installed on the inlet side of the compressor 4 as desired. Or a liquid gas heat exchanger that exchanges heat without mixing the refrigerant from the condenser 5 to the expansion valve 6 and the refrigerant from the evaporator 7 to the compressor 4 may be installed. This applies not only to the first heat pump 2 but also to the second heat pump 3. Moreover, when the 1st heat pump 2 and the 2nd heat pump 3 are a multistage, it is the same also about the heat pump of each stage which comprises it.

  The second heat pump 3 is a vapor compression heat pump, and in the present embodiment, is composed of upper and lower two-stage heat pumps 3A and 3B. The upper and lower heat pumps 3A and 3B constituting the second heat pump 3 have basically the same configuration as the single-stage first heat pump 2 described above. That is, the compressors 8A and 8B, the condensers 9A and 9B, the expansion valves 10A and 10B, and the evaporators 11A and 11B are sequentially connected in a ring shape.

  Then, the heat pumps 3A and 3B at the upper and lower stages are connected as follows. In other words, the indirect heat exchanger 12 is provided which receives the refrigerant from the compressor 8B of the lower heat pump 3B and the refrigerant from the expansion valve 10A of the upper heat pump 3A and exchanges heat without mixing both refrigerants. Reference numeral 12 denotes a condenser 9B of the lower heat pump 3B and an evaporator 11A of the upper heat pump 3A. Accordingly, the second heat pump 3 draws up heat from the heat source fluid in the lower evaporator 11B, and heats water to generate steam in the upper condenser 9A.

  Typically, the pressure and temperature of the refrigerant from the upper expansion valve 10 </ b> A of the second heat pump 3 to the compressor 8 </ b> A are the pressure and temperature of the refrigerant from the expansion valve 6 of the first heat pump 2 to the compressor 4. Identical. In this case, the upper heat pump 3A of the second heat pump 3 and the first heat pump 2 can have the same configuration. The heat source fluid passed through the evaporator 7 of the first heat pump 2 and the lower evaporator 11B of the second heat pump 3 in order is cooled by the first heat pump 2, and the lower heat pump 3B of the second heat pump 3 is used. And the pressure and temperature of the refrigerant from the upper expansion valve 10A of the second heat pump 3 to the compressor 8A are the same as the pressure and temperature of the refrigerant from the expansion valve 6 to the compressor 4 of the first heat pump 2. To do. Further, in the condenser 5 of the first heat pump 2 and the upper condenser 9A of the second heat pump 3, water can be heated to generate steam of the same pressure (including steam within the allowable pressure range). . In this case, if the refrigerant temperature on the high temperature side of the first heat pump 2 is T1, the refrigerant temperature on the low temperature side is T1 ′, and the refrigerant temperature on the high temperature side of the second heat pump 3 is T2, then T1 ′ <T2 <(T1 + ( T1-T1 ′)).

  However, the pressure and temperature of the refrigerant from the upper expansion valve 10A of the second heat pump 3 to the compressor 8A may be different from the pressure and temperature of the refrigerant from the expansion valve 6 of the first heat pump 2 to the compressor 4. . Moreover, you may make it output a different pressure or temperature in the condenser 5 of the 1st heat pump 2, and the condenser 9A of the upper stage of the 2nd heat pump 3. FIG. Furthermore, the refrigerant of each heat pump 2, 3A, 3B may be the same or different. The refrigerant to be used is not particularly limited, but a hydrofluorocarbon (HFC) having 4 or more carbon atoms (for example, R-365mfc) or a mixture obtained by adding water and / or a fire extinguishing liquid, alcohol (for example, ethyl alcohol, methyl alcohol). Alternatively, trifluoroethanol (TFE)) or water added with water and / or a fire extinguishing liquid, or water (for example, pure water or soft water) is preferably used.

The steam generation system 1 may be provided with one or more sub heat exchangers among various sub heat exchangers 13 to 17 described below.
(A) The first sub heat exchanger 13 is an indirect heat exchanger of refrigerant and water from the upper condenser 9A to the expansion valve 10A of the second heat pump 3, and functions as a refrigerant subcooler.
(B) The 2nd sub heat exchanger 14 is an indirect heat exchanger of the refrigerant | coolant and water from the condenser 5 of the 1st heat pump 2 to the expansion valve 6, and functions as a subcooler of a refrigerant | coolant.
(C) The third sub heat exchanger 15 is an indirect heat exchanger between the refrigerant and the heat source fluid from the evaporator 7 of the first heat pump 2 to the compressor 4 and functions as a refrigerant superheater.
(D) The fourth sub heat exchanger 16 is an indirect heat exchanger between the refrigerant and the heat source fluid from the lower evaporator 11B to the compressor 8B of the second heat pump 3, and functions as a refrigerant superheater.
(E) The fifth sub heat exchanger 17 is an indirect heat exchanger between the refrigerant from the lower compressor 8B to the condenser 9B and the refrigerant from the upper evaporator 11A to the compressor 8A. .

Next, water and steam distribution channels will be described.
The upper condenser 9A of the second heat pump 3, the first sub heat exchanger 13 installed if desired, the condenser 5 of the first heat pump 2, and the second sub heat exchanger 14 installed if desired. These are installed in an appropriate order, and water is supplied to derive the steam. Any one of the distribution channels shown in FIG. 2 is used.

  FIG. 2 shows the first sub heat exchanger 13 installed as desired, the upper condenser 9 </ b> A of the second heat pump 3, the second sub heat exchanger 14 installed as desired, and the condensation of the first heat pump 2. It is a figure which shows the distribution | circulation order of the water and steam to the container 5. FIG. The numbers in the figure indicate the order of distribution to the heat exchangers 13, 9A, 14, and 5, and the number 0 indicates that the heat exchanger is not installed. Moreover, although the same number has shown installing in parallel, the heat exchangers of the same number can be mutually replaced. In addition, although the condensers 5 and 9A of each heat pump 2 and 3 are each installed one by one in the example of illustration, you may comprise from a some heat exchanger in series or parallel.

  Several specific examples will be described. For example, the first line is 1-2-1-2. That is, the first sub heat exchanger 13 is 1, the upper condenser 9A of the second heat pump 3 is 2, the second sub heat exchanger 14 is 1, and the condenser 5 of the first heat pump 2 is 2. In this case, water and steam are passed through the first sub heat exchanger 13 and the second sub heat exchanger 14 in parallel, and then the upper condenser 9 </ b> A of the second heat pump 3 and the condenser of the first heat pump 2. 5 is passed in parallel. At this time, after passing through the first sub heat exchanger 13, it passes through the upper condenser 9 </ b> A of the second heat pump 3, and after passing through the second sub heat exchanger 14, passes through the condenser 5 of the first heat pump 2. May be paralleled. Further, as described above, the heat exchangers having the same number can be interchanged with each other, and therefore the upper condenser 9A of the second heat pump 3 and the condenser 5 of the first heat pump 2 having the second order number are connected. After passing through the first sub heat exchanger 13, the condenser 5 of the first heat pump 2 is passed through, and after passing through the second sub heat exchanger 14, the condenser 9A in the upper stage of the second heat pump 3 is passed through. May be paralleled.

  The fifth line is 1-3-2-4. That is, the first sub heat exchanger 13 is 1, the upper condenser 9A of the second heat pump 3 is 3, the second sub heat exchanger 14 is 2, and the condenser 5 of the first heat pump 2 is 4. In this case, water and steam are sequentially passed through the first sub heat exchanger 13, the second sub heat exchanger 14, the upper condenser 9 </ b> A of the second heat pump 3, and the condenser 5 of the first heat pump 2.

  Furthermore, in the 10th line, it is 1-2-0-2. That is, the first sub heat exchanger 13 is 1, the upper condenser 9A of the second heat pump 3 is 2, the second sub heat exchanger 14 is 0, and the condenser 5 of the first heat pump 2 is 2. In this case, the second sub heat exchanger 14 is not installed, and water and steam are passed through the first sub heat exchanger 13 and then condensed in the upper condenser 9A and the first heat pump 2 of the second heat pump 3. The device 5 is passed in parallel.

  In any case, basically, when the first sub heat exchanger 13 and / or the second sub heat exchanger 14 are installed with respect to the flow order of water and steam, the sub heat exchangers 13 and 14 are installed. Is preferably set before the condensers 5 and 9A of the heat pumps 2 and 3.

  By the way, the upper condenser 9A of the second heat pump 3, the first sub heat exchanger 13 installed if desired, the condenser 5 of the first heat pump 2, and the second sub heat exchanger 14 installed if desired. As described above, water and / or steam are passed in an appropriate order as described above. Normally, water is gradually heated while sequentially passing through these heat exchangers, and is saturated from the most downstream heat exchanger. Steam is derived. However, in each of the condensers 5 and 9A, vapors having the same pressure or different pressures may be generated.

Next, the flow path of the heat source fluid will be described.
The evaporator 7 of the first heat pump 2, the third sub heat exchanger 15 installed if desired, the lower evaporator 11B of the second heat pump 3, and the fourth sub heat exchanger 16 installed if desired. These are installed in an appropriate order, and the heat source fluid is passed therethrough, and any of those shown in FIG.

  FIG. 3 shows the third sub heat exchanger 15 installed if desired, the evaporator 7 of the first heat pump 2, the fourth sub heat exchanger 16 installed if desired, and the lower stage evaporation of the second heat pump 3. It is a figure which shows the distribution | circulation order of the heat source fluid to the container 11B. The numbers in the figure indicate the distribution order to each heat exchanger 15, 7, 16, 11B, and the number 0 indicates that the heat exchanger is not installed. Moreover, although the same number has shown installing in parallel, the heat exchangers of the same number can be mutually replaced. In addition, although the evaporators 7 and 11B of each heat pump 2 and 3B are each installed in the example of illustration, you may comprise from a some heat exchanger in series or in parallel.

  Several specific examples will be described. For example, the first line is 1-2-3-4. That is, the third sub heat exchanger 15 is 1, the evaporator 7 of the first heat pump 2 is 2, the fourth sub heat exchanger 16 is 3, and the lower evaporator 11B of the second heat pump 3 is 4. In this case, the heat source fluid is sequentially passed through the third sub heat exchanger 15, the evaporator 7 of the first heat pump 2, the fourth sub heat exchanger 16, and the lower evaporator 11 </ b> B of the second heat pump 3.

  The second line is 1-2-1-3. That is, the third sub heat exchanger 15 is 1, the evaporator 7 of the first heat pump 2 is 2, the fourth sub heat exchanger 16 is 1, and the lower evaporator 11B of the second heat pump 3 is 3. In this case, the heat source fluid is passed through the third sub heat exchanger 15 and the fourth sub heat exchanger 16 in parallel, and then the evaporator 7 of the first heat pump 2 and the lower evaporator of the second heat pump 3. 11B in order.

  In the fourth line, it is 1-2-0-3. That is, the third sub heat exchanger 15 is 1, the evaporator 7 of the first heat pump 2 is 2, the fourth sub heat exchanger 16 is 0, and the lower evaporator 11B of the second heat pump 3 is 3. In this case, the fourth sub heat exchanger 16 is not installed, and the heat source fluid passes through the third sub heat exchanger 15 and then evaporates in the lower stage of the evaporator 7 of the first heat pump 2 and the second heat pump 3. It passes through the vessel 11B in order.

  In any case, basically, it is preferable that the lower-stage evaporator 11B of the second heat pump 3 is set behind the flow sequence of the heat source fluid. In other words, the heat source fluid passes through the evaporator 7 of the first heat pump 2 and then passes through the lower evaporator 11 </ b> B of the second heat pump 3.

  FIG. 4 is a view showing the relationship between the fifth sub heat exchanger 17 installed as desired and the lower condenser 9B (upper evaporator 11A) of the second heat pump 3, and the lower part of the second heat pump 3. It is a figure which shows the distribution order of the refrigerant | coolant. The numbers in the figure indicate the order of distribution to the heat exchangers 17 and 12, and the number 0 indicates that the heat exchanger is not installed.

  More specifically, the first line is 1-2. That is, the fifth sub heat exchanger 17 is 1, and the lower condenser 9B of the second heat pump 3 is 2. In this case, the refrigerant from the lower compressor 8B of the second heat pump 3 is passed through the fifth sub heat exchanger 17, and then passed through the condenser 9B and sent to the expansion valve 10B. Note that the refrigerant from the upper expansion valve 10A of the second heat pump 3 passes through the evaporator 11A, and then passes through the fifth sub heat exchanger 17 and is sent to the compressor 8A.

  The second line is 0-1. That is, the fifth sub heat exchanger 17 is 0, and the lower condenser 9B of the second heat pump 3 is 1. In this case, the fifth sub heat exchanger 17 is not installed, and the refrigerant from the lower compressor 8B of the second heat pump 3 is sent to the expansion valve 10B after passing through the condenser 9B. Note that the refrigerant from the upper expansion valve 10A of the second heat pump 3 is passed through the evaporator 11A and then sent to the compressor 8A.

  In the steam generation system 1 of the present embodiment, for example, drain is used as the heat source fluid as described above. As an example, drain of 158 ° C. is supplied to the evaporator 7 of the first heat pump 2 and discharged at 125 ° C., and then supplied to the lower evaporator 11 B of the second heat pump 3 and discharged at 80 ° C. The first heat pump 2 has a refrigerant temperature of 120 ° C. on the low temperature side (inlet side of the compressor 4) and a refrigerant temperature of 163 ° C. on the high temperature side (outlet side of the compressor 4). Is generated. The lower heat pump 3B of the second heat pump 3 has a refrigerant temperature of 75 ° C. on the low temperature side (the inlet side of the compressor 8B), and the upper heat pump 3A has a refrigerant temperature of 120 ° C. on the low temperature side (the inlet side of the compressor 8A). The refrigerant temperature on the high temperature side (the outlet side of the compressor 8A) is 163 ° C., and the condenser 9A generates 158 ° C. steam. In this case, as described above, the first heat pump 2 and the upper heat pump 3A of the second heat pump 3 correspond to each other.

  According to the steam generation system 1 of the present embodiment, the heat source fluid passes through the evaporator 7 of the first heat pump 2 and then passes through the lower evaporator 11 </ b> B of the second heat pump 3. And the 2nd heat pump 3 can cover the part cooled in the 1st heat pump 2 by making the stage number of the 2nd heat pump 3 more than the 1st heat pump 2. FIG. Moreover, in the 1st heat pump 2, the temperature difference which pumps up can be reduced, the electric power of the compressor 4 can be decreased by that much, and the efficiency of the steam generation system 1 can be improved.

  In other words, the steam generation system 1 can increase the coefficient of performance because a part (typically half) of the energy to be pumped is pumped from the middle stage. Moreover, since the energy pumped from the lowest stage can be reduced (typically halved), the capacity of the compressor 8B on the lower stage side (lower heat pump 3B of the second heat pump 3) can be reduced.

FIG. 5 is a graph comparing the coefficient of performance between the steam generation system 1 of the present embodiment and a conventionally known two-stage heat pump. In the figure, the solid line shows the steam generation system 1 of the present embodiment, and the broken line shows a conventionally known two-stage heat pump. Further, here, the case where drain is used as the heat source fluid is shown, and the final drain temperature after passing through the lower evaporator 11B of the second heat pump 3 is taken as the horizontal axis, and the theoretical coefficient of performance is taken as the vertical axis. Yes. Note that the refrigerant is R-365mfc, and the above-described conditions, that is, the case of generating steam at 158 ° C. (5 kgf / cm ² (G)) using a drain having an initial temperature of 158 ° C. was studied.

  As shown in this figure, regardless of the temperature of the heat source fluid (drain), the steam generation system 1 of this embodiment is more efficient than the conventionally known two-stage heat pump. Note that the conventionally known two-stage heat pump is equivalent to the state of only the second heat pump 3 by omitting the installation of the first heat pump 2 in FIG.

Figure 6A is a saturated water condition T _h of the inlet portion of the fluid given thermal state of the outlet portion of the fluid supplied heat is saturated vapor of the T _h (i.e. fluid given heat gives latent heat The condition of the saturated fluid having the inlet of the fluid supplying the heat is T _h and the state of the supercooled water having the outlet of the fluid supplying the fluid being T ₁ (that is, the fluid applying the heat is deprived of sensible heat) 2 is a TS diagram when ideally pumping heat (hereinafter referred to as an ideal cycle). That is, the vertical axis represents temperature and the horizontal axis represents entropy.

This ideal cycle, that is, the area of a triangle surrounded by a solid line, is the minimum power (ideal power) for realizing the above condition. The coefficient of performance COP at this time is 2 × (T _h / (T _h −T _l )).

On the other hand, FIG. 6B is a TS diagram of a conventionally known single-stage heat pump (reverse Carnot cycle). However, FIG. 6B shows a case where the expansion valve outlet loss and the compressor overheating loss are ignored and the heat exchange performance is infinite. In this case, the coefficient of performance _{COP = T h / (T h} -T l). As indicated by a two-dot chain line A, the same applies even if the heat pump is vertically arranged in two stages.

  Comparing FIG. 6A and FIG. 6B, it can be said that the area obtained by subtracting the area of the triangle of FIG. 6A from the area of the square of FIG.

On the other hand, FIG. 7 is a TS diagram of the steam generation system of the present embodiment. In this case, the coefficient of performance COP = (4/3) × (T _h / (T _h −T _l )). That is, it becomes 4/3 times the efficiency of a conventionally known single-stage heat pump. Note that T _m = (T _h + T _l ) / 2 and S _m = (S ₁ + S ₂ ) / 2. Compared to FIG. 6B, the lower right portion is missing, so that the power can be reduced by this amount and the efficiency can be increased.

In FIG. 7, the number of stages is two. However, if the number of stages is increased, the area surrounded by the cycle can be further reduced as shown in FIG. 8, and the efficiency of the steam generation system 1 can be further improved. Can do. When the number of stages is infinite, theoretically, COP = 2 × (T _h / (T _h −T _l )). That is, the efficiency of the conventionally known single-stage heat pump can be doubled. A specific configuration of the steam generation system 1 with the increased number of stages will be described later.

  FIG. 9 is a schematic diagram showing Example 2 of the steam generation system 1 of the present invention. The steam generation system 1 according to the second embodiment is basically the same as the first embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  The second embodiment is different from the first embodiment in the configuration of the second heat pump 3. In the first embodiment, the upper heat pump 3A and the lower heat pump 3B are connected by the indirect heat exchanger 12, but in the second embodiment, the upper heat pump 3A and the lower heat pump 3B are connected by the intermediate cooler 18.

  Specifically, an intermediate cooler 18 is provided that receives the refrigerant from the compressor 8B of the lower heat pump 3B and the refrigerant from the expansion valve 10A of the upper heat pump 3A, and directly contacts both refrigerants to exchange heat. The intermediate cooler 18 is the condenser 9B of the lower heat pump 3B and the evaporator 11A of the upper heat pump 3A. More specifically, a hollow tank (direct heat exchanger) is used as the intermediate cooler 18 and receives the refrigerant from the compressor 8B of the lower heat pump 3B and the refrigerant from the expansion valve 10A of the upper heat pump 3A. The refrigerant is condensed directly from the compressor 8B of the lower heat pump 3B and vaporized from the expansion valve 10A of the upper heat pump 3A. The liquid refrigerant thus obtained is sent to the expansion valve 10B of the lower heat pump 3B, while the gas refrigerant may be sent to the compressor 8A of the upper heat pump 3A.

With such a configuration, the fifth sub heat exchanger 17 is not installed in the second embodiment. The refrigerant from the compressor 8B of the lower heat pump 3B is supplied to the inlet side of the compressor 8A of the upper heat pump 3A as shown by a two-dot chain line A instead of or in addition to the supply to the intermediate cooler 18. You may supply.
Further, when the refrigerant from the compressor 8B of the lower heat pump 3B is supplied to the inlet side of the compressor 8A of the upper heat pump 3A, as indicated by a two-dot chain line A, instead of being supplied to the intermediate cooler 18, In addition, the liquid phase part of the intercooler 18 may be connected to the outlet side of the compressor 8B of the lower heat pump 3B.
Alternatively, the refrigerant from the compressor 8B of the lower heat pump 3B is replaced with or supplied from the intermediate cooler 18, as indicated by a two-dot chain line B, from the expansion valve 10A of the upper heat pump 3A to the intermediate cooler. 18 may be merged into the refrigerant flow path to 18. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  FIG. 10 is a schematic diagram showing Example 3 of the steam generation system 1 of the present invention. The steam generation system 1 according to the third embodiment is basically the same as the first embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  The third embodiment is different from the first embodiment in the configuration of the second heat pump 3. In the first embodiment, the upper heat pump 3A and the lower heat pump 3B are connected by the indirect heat exchanger 12, but in the third embodiment, the upper heat pump 3A and the lower heat pump 3B are connected by the intermediate cooler 19.

  Specifically, the refrigerant from the compressor 8B of the lower heat pump 3B and the refrigerant from the expansion valve 10A of the upper heat pump 3A are received, and both the refrigerants are brought into direct contact to exchange heat, and both the refrigerant and the upper heat pump are exchanged. An intermediate cooler 19 for exchanging heat without mixing the refrigerant supplied to the expansion valve 10B of the lower heat pump 3B without passing through the expansion valve 10A from the condenser 9A of 3A is provided, and this intermediate cooler 19 is connected to the lower heat pump 3B. The condenser 9B and the evaporator 11A of the upper heat pump 3A. More specifically, an indirect heat exchanger that exchanges heat without mixing the fluids of the first region 19A and the second region 19B is used as the intermediate cooler 19, and the compressor of the lower heat pump 3B is used in the first region 19A. While the refrigerant from 8B and the refrigerant from the expansion valve 10A of the upper heat pump 3A are directly heat-exchanged, the refrigerant passes through the second region 19B from the condenser 9A of the upper heat pump 3A without passing through the expansion valve 10A. What is necessary is just to supply to the expansion valve 10B of the heat pump 3B. In this case, the refrigerant from the compressor 8B of the lower heat pump 3B is subjected to intermediate cooling with the refrigerant from the expansion valve 10A of the upper heat pump 3A in the intermediate cooler 19, and then further pressurized and heated in the compressor 8A of the upper heat pump 3A. And is condensed in the condenser 9A of the upper heat pump 3A. A part of the liquid refrigerant is sent to the first region 19A of the intermediate cooler 19 via the expansion valve 10A of the upper heat pump 3A, while the remaining liquid refrigerant is sent to the second region 19B of the intermediate cooler 19. Then, the pressure is reduced by the expansion valve 10B of the lower heat pump 3B, vaporized in the evaporator 11B of the lower heat pump 3B, and then returned to the compressor 8B of the lower heat pump 3B again.

  With such a configuration, the fifth sub heat exchanger 17 is not installed in the third embodiment. The refrigerant from the compressor 8B of the lower heat pump 3B is supplied from the intermediate cooler 18 of the upper heat pump 3A to the compressor as indicated by a two-dot chain line A instead of or in addition to the supply to the intermediate cooler 18. The refrigerant may be supplied to the refrigerant flow path to 8A or may be joined to the refrigerant flow path from the expansion valve 10A of the upper heat pump 3A to the intermediate cooler 18 as indicated by a two-dot chain line B. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  In each said Example, although the 1st heat pump 2 was comprised by the single stage and the 2nd heat pump 3 was comprised by heat pump 3A, 3B of 2 steps | paragraphs, the stage number of the 2nd heat pump 3 is more than the stage number of the 1st heat pump 2. As long as there are many, the number of stages of the heat pumps 2 and 3 can be changed as appropriate. In addition, in the multistage (multistage) heat pump, in addition to a single multistage heat pump such as the second heat pump 3 in FIG. 9, a multiple (multiple) heat pump such as the second heat pump 3 in FIG. A combination heat pump is included.

  FIG. 11 shows an example in which the second heat pump 3 is arranged in three stages. Here, the heat pumps adjacent to each other in the vertical direction are connected by the indirect heat exchanger 12 similar to that in the first embodiment, but part or all of the heat pumps is the same as in the second embodiment or the third embodiment. The devices 18 and 19 may be connected. That is, when the first heat pump 2 and the second heat pump 3 are arranged in a plurality of upper and lower stages, the adjacent upper and lower heat pumps are connected by any relationship shown in the second heat pump 3 of FIGS. 1, 9, and 10. Also good.

  In the case where the second heat pump 3 has a plurality of stages, when the first sub heat exchanger 13 is to be installed, the first sub heat exchanger 13 may be installed in the uppermost heat pump 3A. Similarly, when the first heat pump 2 has a plurality of stages, when the second sub heat exchanger 14 is to be installed, the second sub heat exchanger 14 may be installed in the uppermost heat pump.

  In addition, when the first heat pump 2 has a plurality of stages, when the third sub heat exchanger 15 is to be installed, the third sub heat exchanger 15 may be installed in the lowermost heat pump. Similarly, when the second heat pump 3 has a plurality of stages, when the fourth sub heat exchanger 16 is to be installed, the fourth sub heat exchanger 16 may be installed in the lowermost heat pump 3B.

  Furthermore, in the case where the second heat pump 3 has a plurality of stages, when the refrigerant of the heat pumps of adjacent stages is indirectly heat-exchanged, the refrigerant and the upper stage from the compressor (8) to the condenser (9) of the lower stage heat pump You may provide the 5th sub heat exchanger 17 with the refrigerant | coolant from the evaporator (11) of a heat pump to a compressor (8). Similarly, in the case where the first heat pump 2 has a plurality of stages, when indirect heat exchange is performed between the refrigerants of the adjacent heat pumps, the refrigerant from the compressor (4) to the condenser (5) of the lower heat pump You may provide the 6th sub heat exchanger with the refrigerant | coolant from the evaporator (7) of an upper stage heat pump to a compressor (4). Other configurations are the same as those in the above embodiments, and thus the description thereof is omitted.

  In each said Example, you may comprise the 2nd heat pump 3 from several heat pump 3, 3, ... installed in parallel. In other words, in each of the above-described embodiments, in addition to the first heat pump 2 and the second heat pump 3, a third heat pump may be provided, and the fourth heat pump, the fifth heat pump,. You may install the heat pump of (n> = 2) in parallel. Also in this case, in the n heat pumps, the heat source fluid is sequentially passed through the lowermost evaporators 7 and 16, and the number of stages is increased in order in which the heat source fluid is passed (preferably, the number is increased by one). What is necessary is just to heat the water in each of the uppermost condensers 5 and 9A and generate steam.

  FIG. 12A shows an example in which the second heat pump is composed of a plurality of heat pumps 3 and 20 installed in parallel. In other words, a single-stage first heat pump 2, a second heat pump 3 with a higher number of stages, and a third heat pump 20 with a higher number of stages are installed in parallel. At this time, the first heat pump 2, the second heat pump 3, and the third heat pump 20 are preferably configured to increase the number of stages one by one. That is, typically, as shown in the drawing, the first heat pump 2 is composed of a single-stage heat pump, the second heat pump 3 is composed of a two-stage heat pump, and the third heat pump 20 is composed of a three-stage heat pump.

  The reason why the number of steps is increased step by step is as follows. 12B is a TS diagram when the first heat pump 2 has a single stage and the second heat pump 3 has three stages. FIG. 12C shows the first heat pump 2 with a single stage and the second heat pump 3 with a second stage. It is a TS diagram at the time of using two stages and the third heat pump 20 as three stages. When comparing FIG. 12B and FIG. 12C, the area of the loss that is hatched can be reduced in FIG. 12C. Therefore, it is preferable to increase each heat pump of the steam generation system 1 by one stage.

  In any of the heat pumps 2, 3, and 20, the heat pumps vertically adjacent to each other are connected by the indirect heat exchanger 12 similar to that of the first embodiment, but a part or all of the heat pumps are the same as those in the second embodiment or the second embodiment The intermediate coolers 18 and 19 similar to those in Example 3 may be connected. That is, when making each heat pump into a plurality of upper and lower stages, the adjacent upper and lower heat pumps may be connected in any relationship shown in the second heat pump 3 of FIGS. 1, 9 and 10. Other configurations are the same as those in the above embodiments, and thus the description thereof is omitted.

  FIG. 13 is a schematic diagram showing an example of a steam system 21 using the steam generation system 1 of the first embodiment. Here, for convenience of explanation, the lowermost evaporator 7 of the first heat pump 2, the third sub heat exchanger 15 installed if desired, the lowermost evaporator 11B of the second heat pump 3, and the optional installation. The fourth sub heat exchanger 16 is referred to as a heat pump for heat pumping (7, 15, 11B, 16). Further, the uppermost condenser 9A of the second heat pump 3, the first sub heat exchanger 13 installed if desired, the upper condenser 5 of the first heat pump 2, and the second sub installed optionally. The heat exchanger 14 is referred to as a steam generating heat exchanger (9A, 13, 5, 14).

The steam system 21 includes a steam generation system 1 and a boiler 22.
The steam generation system 1 uses the configuration of the first embodiment, but the configuration of the other embodiments described above may be used. In any case, the steam generation system 1 pumps up the heat of the drain in the heat pump for heat pump (7, 15, 11B, 16), and in the heat exchanger for steam generation (9A, 13, 5, 14). Water is heated to generate steam. For this purpose, the drain from the steam using facility 23 is passed through the heat pump for heat pumping up (7, 15, 11B, 16). The way of draining the evaporators 7 and 11B and the sub heat exchangers 15 and 16 as the heat pumps for heat pumping (7, 15, 11B, 16) is as described with reference to FIG.

  On the other hand, water can be supplied to the steam generating heat exchanger (9A, 13, 5, 14) by the water supply pump 24, and a desired amount is supplied to the steam generating heat exchanger (9A, 13, 5, 14). Of water is stored. Specifically, pure water or soft water, or instead of or mixed with this, drain from the steam using facility 23 is generated for steam generation via the feed water pump 24, feed water valve 25, and check valve 26. It is supplied to the heat exchanger (9A, 13, 5, 14). The way of passing water and steam to the condensers 9A, 5 and the sub heat exchangers 13, 14 as the heat exchangers for steam generation (9A, 13, 5, 14) is as described based on FIG. is there.

  The boiler 22 is typically a fuel-fired boiler or an electric boiler. A fuel-fired boiler is a device that vaporizes water by burning fuel, and the presence or amount of combustion is adjusted so as to maintain the vapor pressure as desired. The electric boiler is a device that vaporizes water using an electric heater, and the presence or amount of power supplied to the electric heater is adjusted so as to maintain the vapor pressure as desired. Water can be supplied to the boiler 22 via the feed water pump 27 and the check valve 28, and the water level in the boiler body of the boiler 22 is maintained as desired.

  The steam path 29 from the steam generating heat exchanger (9A, 13, 5, 14) and the steam path 30 from the boiler 22 are configured to merge. This merging can also be performed using a steam header. Further, a check valve 31 is provided in the steam path 29 from the steam generating heat exchanger (9A, 13, 5, 14) on the upstream side of the junction. This prevents the steam from the boiler 22 from flowing backward to the steam generating heat exchanger (9A, 13, 5, 14) while the steam generating system 1 is stopped.

  Further, a boiler steam supply valve 32 is provided in the steam path 30 from the boiler 22 on the upstream side of the junction. In the illustrated example, the boiler steam supply valve 32 is a self-reducing pressure reducing valve (secondary pressure regulating valve). The upstream side of the boiler steam supply valve 32 is maintained at a higher pressure by the boiler 22 than the downstream side.

  Steam from the steam generation system 1 or the boiler 22 is sent to one or a plurality of steam use facilities 23. The drain of the steam using facility 23 is discharged to the separator container 34 having a hollow container shape through the first steam trap 33. A first flow path 35 is connected to the upper part of the separator tank 34 and a second flow path 36 is connected to the lower part.

  The first flow path 35 is provided with a heat pump (7, 15, 11B, 16), a second steam trap, and 37 in order from the separator tank 34 side. With this configuration, the drain of the steam using facility 23 is discharged under a low pressure by the first steam trap 33, and then passes through the heat pump for heat pumping (7, 15, 11B, 16). The gas is further discharged under a low pressure (typically atmospheric pressure) by the two vapor trap 37. That is, the drain of the steam use facility 23 is discharged through the first steam trap 33 to become flash steam and its condensed water, and is passed through the heat pump for heat pumping (7, 15, 11B, 16). After being cooled (including supercooling), it is discharged from the second steam trap 37. In such a configuration, the fluid that gives heat to the refrigerant in the heat pump for heat pumping (7, 15, 11B, 16) can be maintained at a temperature exceeding 100 ° C. at a pressure exceeding atmospheric pressure. The waste water from the second steam trap 37 may be discarded as it is, or may be supplied to the water supply tank 38 to the boiler 22 and / or the steam generating heat exchanger (9A, 13, 5, 14). However, the steam supply heat exchanger (9A, 13, 5, 14) may be used as water supply without using the water supply tank 38.

  On the other hand, the second flow path 36 is provided with a discharge valve 39. In the illustrated example, the discharge valve 39 is a self-reducing pressure reducing valve (primary pressure regulating valve). With such a configuration, the drain of the steam using facility 23 can be discharged to a lower pressure (typically atmospheric pressure) by the discharge valve 39 after being discharged to a lower pressure by the first steam trap 33. Is done. Then, the fluid from the discharge valve 39 may be discarded as it is, or may be supplied to the water supply tank 38 to the boiler 22 and / or the heat exchanger (9A, 13, 5, 14) for generating steam, You may use as water supply to the heat exchanger (9A, 13, 5, 14) for steam generation, without passing through such a water supply tank 38. FIG.

  Further, in case of an emergency or power failure, a normally closed electromagnetic valve 40 is provided in the first flow path 35 between the separator tank 34 and the heat pump for heat pumping (7, 15, 11B, 16). On the other hand, the second flow path 36 is preferably provided with a normally open electromagnetic valve 41 in parallel with the discharge valve 39. In this case, normally, the electromagnetic valve 40 of the first flow path 35 is maintained in an open state, and the electromagnetic valve 41 of the second flow path 36 is maintained in a closed state. In an emergency or a power failure, the electromagnetic valve 40 in the first flow path 35 is closed and the electromagnetic valve 41 in the second flow path 36 is opened, so that the drain from the steam use facility 23 is heated by a heat exchanger for heat pumping ( 7, 15, 11B, 16) without discharging.

The steam generating heat exchanger (9A, 13, 5, 14) is supplied with pure water or soft water, drain from the steam using facility 23, or mixed water of such drain and pure water or soft water. Although the water supply system for that is not particularly limited, for example, the following configuration can be adopted. It should be noted that the drain from the steam using equipment 23 is in a liquid-only state or in a gas-liquid two-phase state (flash steam and its condensed water generated when a drain exceeding the atmospheric pressure is discharged under a lower pressure). It may be.
(A) As indicated by a two-dot chain line A, the drain consisting of the liquid separated in the separator tank 34 is supplied from the upstream side of the discharge valve 39 to the inlet side of the water supply pump 24.
(B) As shown by a two-dot chain line B, the drain after passing through the heat exchanger (7, 15, 11B, 16) for hot pumping is supplied from the upstream side of the second steam trap 37 to the inlet side of the feed water pump 24. To supply. The heat pump for heat pumping (7, 15, 11B, 16) is composed of a plurality of heat exchangers, but as shown by a two-dot chain line B ′, the drain is passed through a part of the heat exchangers. It may be branched and supplied to the inlet side of the water supply pump 24.
(C) As shown by a two-dot chain line C, the drain after passing through the heat exchanger (7, 15, 11B, 16) for hot pumping is supplied from the downstream side of the second steam trap 37 to the inlet side of the feed water pump 24. To supply.
(D) As shown in the broken line area at the bottom of FIG. 13, the drain from the second steam trap 37 and / or the drain from the discharge valve 39 is once accumulated in the water supply tank 38, Water is supplied to the inlet side of the feed pump 24. In addition to the drain from the steam use facility 23, pure water or soft water may be appropriately supplied to the water supply tank 38.
(E) Any two or more combinations of A to D may be used. In this case, two or more water supply channels join together to supply water to the steam generating heat exchangers (9A, 13, 5, 14). However, if the pressure in each water supply channel is different, each water supply channel joins However, instead of providing the water supply pump 24, a water supply pump may be provided in each water supply channel before the junction.

  A first sensor 42 including a pressure sensor is provided at a position where the pressure of the combined steam of the steam from the steam generating heat exchanger (9A, 13, 5, 14) and the steam from the boiler 22 can be detected. Moreover, the 2nd sensor 43 which consists of a pressure sensor or a temperature sensor is provided so that the pressure or temperature of the fluid which passes the heat exchanger (7, 15, 11B, 16) for hot pumping up can be detected. The steam generation system 1 is controlled based on one or both of the detected values of the first sensor 42 and the second sensor 43.

  For example, based on the detected pressure of the first sensor 42, the compressors of the uppermost heat pumps (the compressor 4 of the first heat pump 2 and the upper compressor 8 </ b> A of the second heat pump 3) are controlled. The compressor of each heat pump (the lower compressor 8B of the second heat pump 3) may be controlled based on the refrigerant pressure of the condenser 9B of that stage or the evaporator 11A of the upper stage.

  Alternatively, based on the detected pressure or detected temperature of the second sensor 43, the compressor of each lowermost heat pump (the compressor 4 of the first heat pump 2, the lower compressor 8B of the second heat pump 3) is controlled, The compressors of the upper heat pumps (the upper compressor 8A of the second heat pump 3) may be controlled based on the refrigerant pressure or temperature of the evaporator 11A of the upper stage or the condenser 9B of the lower stage.

  FIG. 14 is a schematic diagram showing a modification of the steam system 21 of FIG. The steam system 21 of FIG. 14 is basically the same as that of FIG. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.

  In the present modification, the drain of the steam using facility 23 is temporarily stored in the buffer tank 44 serving as a drain storage unit. The drain of the buffer tank 44 can be supplied to the heat pump for heat pump (7, 15, 11B, 16) by the first flow path 35, and the heat pump for heat pump ( 7, 15, 11B, 16) and can be discharged.

  Specifically, a first flow path 35 is connected to the lower part of the buffer tank 44, and a third flow path 45 is connected to the upper part thereof. In the first flow path 35, an introduction valve 46, a heat pump (7, 15, 11B, 16) and a second steam trap 37 are provided in this order from the buffer tank 44 side. In the present modification, the introduction valve 46 is a self-reducing pressure reducing valve (secondary pressure regulating valve).

  With such a configuration, the drain of the steam using facility 23 is discharged under a low pressure by the introduction valve 46, and then passes through the heat pump for heat pumping (7, 15, 11B, 16), and then the second steam. The trap 37 discharges further under low pressure (typically under atmospheric pressure). The waste water from the second steam trap 37 may be discarded as it is, or may be supplied to the water supply tank 38 to the boiler 22 and / or the steam generating heat exchanger (9A, 13, 5, 14). However, the steam supply heat exchanger (9A, 13, 5, 14) may be used as water supply without using the water supply tank 38.

  On the other hand, a third steam trap 47 is provided in the third flow path 45. Since the third flow path 45 is connected to the buffer tank 44 above the first flow path 35, the drain overflowing from the buffer tank 44 is discharged from the third flow path 45. Then, the waste water is discharged through the third steam trap 47. The waste water from the third steam trap 47 may be discarded as it is, or may be supplied to the water supply tank 38 to the boiler 22 and / or the steam generating heat exchanger (9A, 13, 5, 14). However, the steam supply heat exchanger (9A, 13, 5, 14) may be used as water supply without using the water supply tank 38.

  Furthermore, it is preferable to provide a normally closed electromagnetic valve 40 between the introduction valve 46 and the buffer tank 44 in the first flow path 35 for an emergency or power failure. In this case, normally, the electromagnetic valve 40 of the first flow path 35 is maintained in an open state. In the event of an emergency or a power failure, the solenoid valve 40 of the first flow path 35 is closed, so that the drain of the steam using facility 23 is heated by the third flow path 45 (13, 9A, 14, 5). It is discharged without going through.

Also in this modification, the steam generating heat exchanger (9A, 13, 5, 14) is supplied with pure water or soft water, drain from the steam using facility 23, or such drain and pure water or soft water. Mixed water is supplied. Although the water supply system for that is not ask | required in particular, For example, it can be set as the following structures similarly to the case of FIG.
(A) As shown by a two-dot chain line A, drain from the buffer tank 44 is upstream from the introduction valve 46 (in the case where the electromagnetic valve 40 is provided, it may be either upstream or downstream from it). Supply to the inlet side of the feed water pump 24.
(B) As shown by a two-dot chain line B, the drain after passing through the heat exchanger (7, 15, 11B, 16) for hot pumping is supplied from the upstream side of the second steam trap 37 to the inlet side of the feed water pump 24. To supply. The heat pump for heat pumping (7, 15, 11B, 16) is composed of a plurality of heat exchangers, but as shown by a two-dot chain line B ′, the drain is passed through a part of the heat exchangers. It may be branched and supplied to the inlet side of the water supply pump 24.
(C) As shown by a two-dot chain line C, the drain after passing through the heat exchanger (7, 15, 11B, 16) for hot pumping is supplied from the downstream side of the second steam trap 37 to the inlet side of the feed water pump 24. To supply.
(D) As shown in the broken line area at the bottom of FIG. 14, the drain from the second steam trap 37 and / or the drain from the third steam trap 47 and the like are once stored in the water tank 38. The water inside is supplied to the inlet side of the water supply pump 24. In addition to the drain from the steam use facility 23, pure water or soft water may be appropriately supplied to the water supply tank 38. Although the water supply tank 38 is also in the case of FIG. 13, it may be possible to store drainage at a pressure exceeding the atmospheric pressure without opening upward.
(E) Any two or more combinations of A to D may be used. In this case, two or more water supply channels join together to supply water to the steam generating heat exchangers (9A, 13, 5, 14). However, if the pressure in each water supply channel is different, each water supply channel joins However, instead of providing the water supply pump 24, a water supply pump may be provided in each water supply channel before the junction.

  The steam generation system 1 of the present invention is not limited to the configuration of each of the above embodiments, and can be changed as appropriate. For example, as an application example of the steam generation system 1, the steam system 21 shown in FIGS. 13 and 14 is used, but it goes without saying that the system can be applied to other systems. Moreover, although the example which used the drain from the steam use equipment 23 was demonstrated as a heat source of the steam generation system 1, it is not restricted to a drain, For example, the water used as the exhaust water from a boiler etc., the cooling water of the exhaust gas, a factory Waste water discharged from the water, water used as cooling water for compressors, water used as cooling water in oil coolers of engines (drive devices such as compressors), water used as cooling water for engine jackets, etc. It may be used.

  Furthermore, the steam generation system 1 is not limited to the case where steam is generated by the heat while lowering the temperature of the heat source fluid. For example, exhaust steam from the steam use facility 23 may be used as the heat source fluid. In that case, for example, in FIG. 1, exhaust steam is passed through the third sub heat exchanger 15 and the evaporator 7 of the first heat pump 2, and after passing through the evaporator 7, the pressure is reduced by a steam trap, an orifice or a pressure reducing valve, It may be passed through the fourth sub heat exchanger 16 and the lowermost evaporator 11B of the second heat pump 3. A steam trap or the like may or may not be provided on the outlet side of the lowermost evaporator 11B of the second heat pump 3 in the exhaust steam flow path. That is, the steam passing through the lowermost evaporator 11B of the second heat pump 3 may be in a state exceeding atmospheric pressure or may be atmospheric pressure. Needless to say, one or both of the third sub heat exchanger 15 and the fourth sub heat exchanger 16 can be omitted.

DESCRIPTION OF SYMBOLS 1 Steam generation system 2 1st heat pump 3 2nd heat pump 4 (1st heat pump) compressor 5 (1st heat pump) condenser 6 (1st heat pump) expansion valve 7 (1st heat pump) evaporator 8 ( 8A, 8B) Compressor 9 (9A, 9B) Condenser 10 (10A, 10B) (Second heat pump) Expansion valve 11 (11A, 11B) (Second heat pump) (Second heat pump) Evaporator 12 Indirect heat exchanger 13 First sub heat exchanger 14 Second sub heat exchanger 15 Third sub heat exchanger 16 Fourth sub heat exchanger 17 Fifth sub heat exchanger 18 Intermediate cooler 19 Intermediate Cooler 21 Steam system 23 Steam use equipment

Claims (8)

A single-stage or multi-stage first heat pump;
With a second heat pump with more stages than this first heat pump,
The heat source fluid is sequentially passed through the lowermost evaporator of the first heat pump and the lowermost evaporator of the second heat pump,
Steam generated by heating water in the uppermost condenser of the first heat pump and the uppermost condenser of the second heat pump. The first heat pump is composed of a single-stage heat pump,
The second heat pump includes a two-stage heat pump,
Heat is drawn from the heat source fluid that is passed through the evaporator of the first heat pump and the lower evaporator of the second heat pump,
The steam generation system according to claim 1, wherein steam is generated by heating water in the upper condenser of the second heat pump and the condenser of the first heat pump. The second heat pump is composed of a plurality of heat pumps installed in parallel,
The plurality of heat pumps are configured such that the heat source fluid is sequentially passed through each lowermost evaporator and the number of stages is increased in the order in which the heat source fluid is passed. It generates. The steam generation system of Claim 1 or Claim 2 characterized by the above-mentioned. The plurality of heat pumps constituting the second heat pump are configured such that the heat source fluid is sequentially passed through each lowermost evaporator, and the number of stages is increased one by one in the order in which the heat source fluid is passed. The steam generating system according to claim 3, wherein water is heated to generate steam. The steam at the same pressure is generated by heating water in the uppermost condenser of the first heat pump and the uppermost condenser of the second heat pump. The steam generation system according to item 1. When the first heat pump and / or the second heat pump is a plurality of stages, adjacent stage heat pumps are connected to each other in any one of the following (a) to (c). The steam generation system according to any one of 1 to 5.
(A) An indirect heat exchanger that receives the refrigerant from the compressor of the lower heat pump and the refrigerant from the expansion valve of the upper heat pump and exchanges heat without mixing the two refrigerants is provided. It is a condenser and an evaporator of the upper heat pump.
(B) An intermediate cooler that receives the refrigerant from the compressor of the lower heat pump and the refrigerant from the expansion valve of the upper heat pump and exchanges heat by bringing both refrigerants into direct contact with each other. It is a condenser and an evaporator of the upper heat pump.
(C) The refrigerant from the compressor of the lower heat pump and the refrigerant from the expansion valve of the upper heat pump are received, the two refrigerants are brought into direct contact and heat exchange is performed, and the expansion valve An intermediate cooler that exchanges heat without mixing with the refrigerant supplied to the expansion valve of the lower heat pump without passing through the intermediate heat exchanger is provided, and this intermediate cooler is a condenser of the lower heat pump and an evaporator of the upper heat pump. Among the following (a) to (f), one or more sub heat exchangers are provided,
When the uppermost condenser of the second heat pump and the first sub heat exchanger are installed, the first sub heat exchanger, the uppermost condenser of the first heat pump, and the second sub heat exchanger When the exchanger is installed, the flow order of water and steam to the second sub heat exchanger is determined when the first sub heat exchanger and / or the second sub heat exchanger is installed. The sub heat exchanger is set to precede the condenser at the top of each heat pump,
When the lowermost evaporator of the first heat pump and the third sub heat exchanger are installed, the third sub heat exchanger, the lowermost evaporator of the second heat pump, and the fourth sub heat When the exchanger is installed, the flow order of the heat source fluid to the fourth sub heat exchanger is set so that the lowermost evaporator of the second heat pump comes later. Item 7. The steam generation system according to any one of Items 1 to 6.
(A) A first sub heat exchanger of refrigerant and water from the uppermost condenser of the second heat pump to the expansion valve.
(B) A second sub heat exchanger of refrigerant and water from the uppermost condenser of the first heat pump to the expansion valve.
(C) A third sub heat exchanger for the refrigerant and the heat source fluid from the lowermost evaporator of the first heat pump to the compressor.
(D) A fourth sub heat exchanger for the refrigerant and the heat source fluid from the lowermost evaporator of the second heat pump to the compressor.
(E) In the case where the second heat pump has a plurality of stages, in the case of indirect heat exchange between the refrigerants of the adjacent heat pumps, the refrigerant from the compressor of the lower heat pump to the condenser and the evaporator of the upper heat pump to the compressor The fifth sub heat exchanger with refrigerant to.
(F) In the case where the first heat pump has a plurality of stages, in the case of indirect heat exchange between the refrigerants of the adjacent heat pumps, the refrigerant from the compressor of the lower heat pump to the condenser and the evaporator of the upper heat pump to the compressor The sixth sub heat exchanger with refrigerant to. The steam generation system according to any one of claims 1 to 7, wherein the heat source fluid is drain from a facility using steam.

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