JP5989459B2 - Sugar solution purification system and sugar solution purification method - Google Patents

Description

  The present invention relates to a sugar liquid purification system and a sugar liquid purification method using a heat pump, and a heat exchange system, and more particularly to a configuration of a heat exchange system.

  Various processes for purifying and purifying various fluids are known.

  For example, the sugar solution is usually purified by a combination of decolorization treatment with activated carbon, bone charcoal, ion exchange resin, and the like and demineralization treatment with ion exchange resin. Desalination treatment systems using ion exchange resins differ depending on the target saccharide. For purification of sucrose liquid, a reverse system that sequentially passes the sucrose liquid through a strongly basic anion exchange resin tower and a weakly acidic cation exchange resin tower, and a sucrose liquid as a strongly basic anion exchange resin and a weakly acidic cation exchange resin Mixed bed system that passes through the mixed bed tower, system that sequentially passes the sucrose liquid through the strongly basic anion exchange resin tower, and the mixed bed tower of strong basic anion exchange resin and weak acid cation exchange resin, etc. Is known (Patent Document 1). For the purification of starch sugar liquor, a double-bed type pre-desalting system using a strongly acidic cation exchange resin and a weakly basic anion exchange resin, a strongly acidic cation exchange resin and a type II strongly basic anion exchange resin were used. A system composed of a mixed bed type finishing desalination system is known. A similar system is used for desalting reducing sugars other than starch sugar (Patent Document 2). In the purification of a sugar solution, it is necessary to adjust the solution temperature for various reasons such as prevention of spoilage of the sugar solution, control of isomerization, and heat resistance of the ion exchange resin (Patent Documents 3 to 6).

  The temperature adjustment of the fluid is not limited to the purification of the sugar solution but is widely performed in various processes that handle the fluid. The temperature of the fluid is generally adjusted by heating and cooling. Heating is performed by supplying heat energy generated by combustion of fossil fuel, electric energy, or the like, or heat energy such as hot water or steam directly to the fluid. Cooling is performed by producing a fluid having a lower temperature than the fluid to be cooled using a refrigerator, a cooling tower, or the like, and directly transferring the thermal energy of the fluid to be cooled to the fluid having the lower temperature. The energy required for heating and cooling is input independently for each heating target and cooling target. However, this method does not allow for energy recovery, and generally increases the total energy consumption of the entire process. For this reason, a heat pump is known as a heat exchange means with high energy efficiency (Patent Document 7).

Japanese Patent No. 2785833 JP 2003-245100 A JP-A-2-295500 JP 2001-128700 A JP 2001-061499 A JP 2002-186500 A JP-A-11-226363

  Since the heat pump receives heat from one heat source and dissipates heat to the other heat source, in principle, the energy recovery efficiency or utilization efficiency is high. Therefore, a heat pump is an effective heat exchange means, particularly in a process in which heating and cooling are performed simultaneously in different parts. An object of the present invention is to provide a sugar liquid refining system using a heat pump, in which energy efficiency is further improved, and in particular, energy consumption can be further reduced.

  The sugar solution purification system of the present invention includes a first pipe in which a first sugar solution is allowed to flow in a plurality of sections sequentially, and a second pipe in which a second sugar solution is caused to flow in a plurality of sections. It has piping and a plurality of heat pumps. The plurality of heat pumps receive heat from at least one section of the first pipe and radiate heat to the plurality of sections of the second pipe, or receive heat from the plurality of sections of the first pipe and receive heat from the plurality of sections of the first pipe. Dissipate heat to at least one section.

  In the heat pump, the refrigerant circulating inside undergoes a thermal cycle of evaporation, compression, condensation, and expansion. In order to increase the efficiency (coefficient of performance) of the heat pump, it is desirable to minimize the difference between the condensation temperature and the evaporation temperature. This means that it is preferable that the temperature difference between the two sugar solutions that perform heat exchange with a heat pump is smaller. When only one heat pump is provided, it is necessary to realize a desired temperature change of the sugar liquid to be heated or cooled with one heat pump, so that the difference between the condensation temperature and the evaporation temperature tends to increase. In contrast, in the present invention, a plurality of heat pumps are provided to receive heat from at least one section of the first pipe and dissipate heat to the plurality of sections of the second pipe, respectively, or from a plurality of sections of the first pipe, respectively. Since it receives heat and dissipates heat to at least one section of the second pipe, the temperature difference between the two sugar liquids in each heat pump can be reduced. Therefore, the heat exchange system of the present invention can suppress the total energy consumption of the heat pump necessary for processing the sugar solution having the same flow rate.

  As described above, according to the present invention, it is possible to provide a sugar liquid purification system using a heat pump, in which energy efficiency is further improved and energy consumption can be further reduced.

1 is a schematic configuration diagram of a heat exchange system according to a first embodiment of the present invention. It is a schematic block diagram of a heat pump. It is a Mollier diagram which shows the thermal cycle of a vapor compression heat pump. It is a schematic block diagram of the heat exchange system of a reference example. It is the schematic which shows the exit temperature of the heat pump of each embodiment and a reference example. It is a schematic block diagram of the heat exchange system which concerns on the 2nd Embodiment of this invention. It is a schematic block diagram of the heat exchange system which concerns on the 3rd Embodiment of this invention. It is a schematic block diagram of the modification of the heat exchange system which concerns on 3rd Embodiment. It is a schematic block diagram of the heat exchange system which concerns on the 4th Embodiment of this invention. It is a schematic block diagram of the modification of the heat exchange system which concerns on 4th Embodiment. It is a schematic block diagram of the other modification of the heat exchange system which concerns on 4th Embodiment. It is a schematic block diagram of the heat exchange system of the comparative example which arranged the heat pump in parallel in embodiment of FIG. It is a schematic block diagram of the sugar liquid refinement | purification process of this invention. 1 is a schematic configuration diagram of a heat exchange system according to Embodiment 1. FIG. It is a schematic block diagram of the heat exchange system which concerns on a comparative example. It is a schematic block diagram of the heat exchange system which concerns on Example 2. FIG.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a heat exchange system 1 according to a first embodiment of the present invention. The heat exchange system 1 can be applied to water treatment such as pure water production in addition to the purification of sugar solution described later.

  The heat exchange system 1 includes a first pipe L1 through which the first fluid F1 flows, a second pipe L2 through which the second fluid F2 flows, and a first pipe. And a plurality of heat pumps HP located between the L1 and the second pipe L2. The first and second fluids F1 and F2 are sugar liquids in the present embodiment, but are not limited to this, and may be any kind of fluid (liquid and gas). The first piping L1 communicates with the first device E11 and the second device E12, and the second piping L2 communicates with the third device E21 and the fourth device E22. These devices E11 to E22 are not limited as long as fluid can be circulated. Ion exchange devices, purification devices using activated carbon, storage tanks, filters, membrane devices, pumps, valves, coolers, heaters, heat exchangers Including all elements that can be installed on piping such as instruments. Moreover, although illustration is abbreviate | omitted, when the 1st piping L1 and the 2nd piping L2 are made into one piping pair, several piping pairs may be provided in parallel. That is, a common first mother pipe is provided upstream and downstream of the plurality of first pipes, and similarly, a common second mother pipe is provided upstream and downstream of the plurality of second pipes. Good. In such a configuration, one pipe pair is an object of the present invention.

  The plurality of heat pumps HP are arranged in series between the first pipe L1 and the second pipe L2. In the illustrated example, four heat pumps (first to fourth heat pumps HP1 to HP4) are shown. Each of the heat pumps HP1 to HP4 receives heat from the plurality of sections S11 to S14 of the first pipe L1 and dissipates heat to the plurality of sections S21 to S24 of the second pipe L2. Therefore, the first fluid F1 flowing through the first pipe L1 is cooled, and the second fluid F2 flowing through the second pipe L2 is heated. The plurality of sections S11 to S14 are sections on the first pipe L1 that exchange heat with the evaporators 11 (described later) of the heat pumps HP1 to HP4, and the first fluid F1 divides these sections into sections S11, S12, and S13. , S14 sequentially. The first to fourth sections S11 to S14 of the first pipe L1 are located in this order from the upstream side to the downstream side in the flow direction D1 of the first fluid F1. As for the temperature of the fluid F1 flowing in the first pipe L1, if the inlet side temperature of the first heat pump HP1 is T10 and the outlet side temperatures of the first to fourth heat pumps HP1 to HP4 are T11 to T14, T10> T11 > T12> T13> T14.

  Each of the heat pumps HP1 to HP4 dissipates heat received from the first to fourth sections S11 to S14 of the first pipe L1 to the first to fourth sections S21 to S24 of the second pipe L2, respectively. The plurality of sections S21 to S24 are sections on the second pipe L2 that exchange heat with the condensers 13 (described later) of the heat pumps HP1 to HP4, and the second fluid F2 divides these sections into sections S21, S22, and S23. , S24 sequentially. The first to fourth sections S21 to S24 of the second pipe L2 are also located in this order from the upstream side to the downstream side with respect to the direction D2 in which the second fluid F2 flows. Regarding the temperature of the fluid F2 flowing in the second pipe L2, if the inlet side temperature of the first heat pump HP1 is T20 and the outlet side temperatures of the first to fourth heat pumps HP1 to HP4 are T21 to T24, T24> T23. > T22> T21> T20.

  In the present embodiment, the first fluid F1 and the second fluid F2 are configured to flow in the same directions D1 and D2 with respect to the arrangement direction A of the plurality of heat pumps HP1 to HP4 (parallel flow).

  In this embodiment, the heat pump HP uses a vapor compression type. As shown in FIG. 2, the heat pump HP includes an evaporator 11 that evaporates refrigerant such as ammonia, carbon dioxide, chlorofluorocarbons, and alternative chlorofluorocarbons such as R410A, a compressor 12 that compresses the refrigerant, and a refrigerant that is condensed. The condenser 13 and the expansion valve 14 for expanding the refrigerant are provided, and these elements 11 to 14 are arranged on the closed loop 15 in this order. The refrigerant is subjected to a thermal cycle of evaporation, compression, condensation, and expansion while circulating in the closed loop 15. The first pipe L1 is located adjacent to the evaporator 11, and heat is taken from the first fluid F1 flowing in the first pipe L1 by the heat of vaporization when the refrigerant evaporates. The evaporated refrigerant is compressed by the compressor 12 and becomes a high-temperature and high-pressure gas phase. The refrigerant is then sent to the condenser 13 where it releases heat and condenses. The second pipe L2 is located adjacent to the condenser, and the condensation heat released during the condensation is given to the second fluid F2 flowing in the second pipe L2. The condensed refrigerant passes through the expansion valve 14 and is cooled under reduced pressure. In this way, heat is received from the first pipe L1 and released to the second pipe L2 during one cycle operation of the heat pump HP.

  In addition to the vapor compression type, the heat pump can also use a thermionic type. The thermoelectronic heat pump is a heat pump using the principle of a so-called thermoelectric element (Peltier element). A p-type semiconductor and an n-type semiconductor provided on a substrate are connected in series via electrodes, and when a current is passed through the pn junction, a junction that changes from n-type to p-type along the direction of the current Then, an endothermic phenomenon occurs, and a heat dissipation phenomenon occurs at a junction portion from p-type to n-type. It is also possible to use a chemical, adsorption or absorption heat pump. For example, a chemical heat pump includes a reaction chamber filled with a hydrate such as calcium chloride and calcium oxide, and a condensing chamber connected to the reaction chamber via a communication pipe. Hydrate such as calcium chloride filled in the reaction chamber receives heat from the piping, whereby water molecules of the hydrate are separated from the hydrate as water vapor and transferred to the condensation chamber. The water vapor transferred to the condensing chamber is condensed and liquefied, and the adjacent piping is heated.

FIG. 3 is a Mollier diagram showing the thermal cycle of the vapor compression heat pump. In the section from point A to point B, the refrigerant exchanges heat with the first fluid F1 having a temperature higher than that of the refrigerant. The refrigerant is heated, deprives heat Q _C from the first pipe L1, the first fluid F1 of high temperature is cooled (cooling step). In the section from point B to point C, the refrigerant receives compression work W by the compressor, and the temperature and pressure rise. In the section from point C to point D, the refrigerant exchanges heat with the second fluid F2 having a temperature lower than that of the refrigerant. The refrigerant is cooled, the amount of heat Q _H is released to the second pipe L2, and the low temperature second fluid F2 is cooled (heating step). In the section from point D to point A, the refrigerant expands while passing through the expansion valve and is depressurized. The amount of heat Q _H is a value obtained by adding the compression work W of the compressor to the amount of heat Q _C (Q _H = Q _C + W). The coefficient of performance during heating is Q _H / W, and the coefficient of performance during cooling is Q _C / W. Therefore, the smaller the W is, the higher the coefficient of performance is, and the energy efficiency is improved.

The cycle ABCD corresponds to the condensation temperature T2 and the evaporation temperature T1. In contrast, cycle ABC′D ′ corresponds to a higher condensation temperature T2 ′ (evaporation temperature T1 is constant), Q _H increases to Q _H ′, but compression work W also increases to W ′. . As is clear from the figure, since Q _H / W ≧ Q _H '/ W', the coefficient of performance during heating decreases as the condensation temperature increases. Similarly, since Q _C / W ≧ Q _C / W ′, the coefficient of performance during cooling decreases as the condensation temperature increases. As described above, in order to increase the coefficient of performance, it is effective to reduce the difference between the condensation temperature T2 and the evaporation temperature T1 (hereinafter referred to as ΔT, ΔT1, etc.) as much as possible.

  For comparison with the present embodiment, FIG. 4 shows a configuration of a reference example in which the same number of heat pumps as those of the present embodiment are provided in parallel. 5A and 5B show the outlet temperatures of the heat pumps in the present embodiment and the reference example 101, respectively. In the figure, D1 and D2 indicate directions in which the first and second fluids F1 and F2 flow. In general, the inlet temperature and the outlet temperature of the pipe are often determined by system requirements, and therefore, the inlet temperature T10, T20 and the outlet temperature T14, T24 of each pipe are the same in this embodiment and the reference example. For the sake of simplicity, the inlet temperature T20 of the second pipe L2 is assumed to be not less than the inlet temperature T10 of the first pipe L1 (T20 ≧ T10) (T20 = T10 in the drawing), and the condensation temperature and the evaporation temperature are It is assumed that it is equal to the heat pump outlet temperature in each section S11 to S24. In this case, all of the heat pumps of the reference examples are operated in a temperature difference cycle of ΔT = T24−T14. On the other hand, in the present embodiment, the first heat pump HP1 has a temperature difference of ΔT1 = T21−T11, the second heat pump HP2 has a temperature difference of ΔT2 = T22−T12, and the third heat pump HP3 has a temperature of ΔT3 = T23−T13. Difference, the fourth heat pump HP4 operates in a cycle of temperature difference of ΔT4 = T24−T14. Since T20 ≧ T10, the relationship of T24> ··· T20 ≧ T10> ··> T14 holds, and the temperature differences ΔT1 to ΔT3 of the first to third heat pumps HP1 to HP3 are smaller than ΔT = T24−T14. . On the other hand, the temperature difference ΔT4 of the fourth heat pump HP4 is equal to ΔT. Accordingly, the first to third heat pumps HP1 to HP3 operate with a higher coefficient of performance than the heat pump of the reference example, and the fourth heat pump HP4 operates with a coefficient of performance equivalent to that of the heat pump of the reference example. For this reason, the energy efficiency of the heat pump as a whole is more advantageous in the embodiment, and the operation can be performed with less power cost.

(Second Embodiment)
FIG. 6 is a schematic configuration diagram of a heat exchange system 2 according to the second embodiment of the present invention. In the present embodiment, the first fluid F1 and the second fluid F2 are configured to flow in opposite directions D1 and D2 with respect to the arrangement direction A of the plurality of heat pumps (opposite flow). Other configurations are the same as those of the first embodiment.

  FIG. 5C shows the outlet temperature of each heat pump in the present embodiment. In order to align the inlet temperatures of the first fluid F1 and the second fluid F2, T10 = T24. In the present embodiment, the first heat pump HP1 has a temperature difference of ΔT1 ′ = T20−T11, the second heat pump HP2 has a temperature difference of ΔT2 ′ = T21−T12, and the third heat pump HP3 has a temperature of ΔT3 ′ = T22−T13. Difference, the fourth heat pump HP4 operates in a cycle of temperature difference of ΔT4 ′ = T23−T14. This embodiment has less variation in ΔT1 ′ to ΔT4 ′ compared to the first embodiment. Therefore, the load of each heat pump becomes comparable, and it is easy to use heat pumps having the same capacity and size. Since ΔT1 ′ to ΔT4 ′ are all smaller than ΔT of the reference example, it is possible to operate with less power cost than the reference example.

(Third embodiment)
FIG. 7 is a schematic configuration diagram of a heat exchange system according to the third embodiment of the present invention. The heat exchange system 3 of the present embodiment includes a plurality of individual circulation channels (intermediate loops) L31 to L34 provided between the first pipe L1 and the individual heat pumps HP1 to HP4. In each of the circulation channels L31 to L34, circulation channel heat exchangers Hx1 to Hx4 that perform heat exchange between the first pipe L1 and the circulation channels L31 to L34, and a medium that flows through the circulation channels L31 to L34 Pumps P31 to P34 for circulating F3 are provided. The plurality of heat pumps HP1 to HP4 receive heat from the individual circulation channels L31 to L34, respectively, and dissipate heat to the plurality of sections S21 to S24 of the second pipe L2. There is no particular limitation on the medium used for the circulation flow path, and in particular, a fluid with low corrosiveness, a fluid that hardly generates scale, and a fluid with high heat exchange efficiency are preferably used. For example, water and CO ₂ can be used, and particularly CO ₂ can carry heat more efficiently than water.

  As shown in FIG. 8, the circulation flow path can also be provided between the second pipe L2 and the individual heat pumps HP1 to HP4. In the heat exchange system 4 of this embodiment, a plurality of circulation channel heat exchangers Hx1 to Hx4 that exchange heat between the second pipe L2 and the individual circulation channels L41 to L44, and the circulation channels L41 to L41. Pumps P41 to P44 for circulating the medium F3 flowing through L44 are provided. The plurality of heat pumps HP1 to HP4 receive heat from the plurality of sections S11 to S14 of the first pipe L1 and dissipate heat to the circulation channels L41 to L44, respectively.

  Although illustration is omitted, the above-described circulation flow paths may be provided between the first pipe L1 and the individual heat pumps HP1 to HP4 and between the second pipe L2 and the individual heat pumps HP1 to HP4. it can.

  By providing the circulation flow path, it is not necessary to introduce a highly corrosive process fluid directly into the heat pump as the first and second fluids F1 and F2 (or one of them), so that the reliability of the heat pump is improved. Is possible. For example, in the examples described later, since the glucose stock solution treated in the cation exchange resin tower is highly corrosive, it is effective from the viewpoint of heat pump protection to perform heat exchange through the circulation channel. Further, the refrigerant of the heat pump does not leak into the process fluid that is highly demanded to prevent contamination, and the process safety can be improved. An example of this is application to food processes that require strict safety.

(Fourth embodiment)
FIG. 9 is a schematic configuration diagram of a heat exchange system according to the fourth embodiment of the present invention. The heat exchange system 5 of the present embodiment includes a single circulation channel (intermediate loop) L5 provided between the first pipe L1 and the plurality of heat pumps HP1 to HP4, and a single pipe on the first pipe L1. A circulation flow path heat exchanger Hx that performs heat exchange between one section S35 and a single section S36 on the circulation flow path L5, and one pump P5 that circulates the medium F3 flowing through the circulation flow path L5. ,have. The circulation path L5 is configured such that the medium F3 sequentially flows while circulating through the plurality of sections S31 to S34, S36. The plurality of heat pumps HP1 to HP4 receive the amount of heat received from the first pipe L1 via the circulation flow path heat exchanger Hx from the plurality of sections S31 to S34 of the circulation flow path L5, and the second pipe L2 Radiate heat to each of the plurality of sections S21 to S24. A plurality of circulation channel heat exchangers Hx can be provided. That is, two or more circulation flow path heat exchangers that perform heat exchange between two or more sections on the first pipe L1 and two or more sections on the circulation flow path L5 are provided. The heat exchanger may receive heat from a plurality of sections on the first pipe L1 and dissipate heat to the plurality of sections of the circulation flow path L5.

  As shown in FIG. 10, the circulation flow path can be provided between the second pipe L2 and the plurality of heat pumps. In the heat exchange system 6 of this embodiment, the circulation flow path heat exchanger Hx that performs heat exchange between the single section S45 on the second pipe L2 and the single section S46 on the circulation path L6; And a single pump P6 that circulates the medium F3 flowing through the circulation flow path L6. The circulation path L6 is configured such that the medium F3 sequentially flows while circulating through the plurality of sections S41 to S44, S46. The plurality of heat pumps HP1 to HP4 radiate the heat received from the plurality of sections S11 to S14 of the first pipe L1 to the plurality of sections S41 to S44 of the circulation channel L6. The amount of heat dissipated is radiated to the single section S45 on the second pipe L2 via the circulation flow path heat exchanger Hx. Also in this case, a plurality of circulation flow path heat exchangers Hx can be provided. That is, two or more circulation flow path heat exchangers for exchanging heat between two or more sections on the second pipe L2 and two or more sections on the circulation flow path L6 are provided. The heat exchanger may receive heat from the plurality of sections of the circulation flow path L6 and dissipate heat to the plurality of sections of the second pipe L2.

  As shown in FIG. 11, the single circulation flow path of this embodiment is provided between the first pipe L1 and the heat pumps HP1 to HP4 and between the second pipe L2 and the heat pumps HP1 to HP4, respectively. You can also. In the heat exchange system 7 of this embodiment, the circulation flow path L5 is between the first pipe L1 and the heat pumps HP1 to HP4, and the circulation flow path L6 is between the second pipe L2 and the heat pumps HP1 to HP4. Each is provided. Refer to the description of FIGS. 9 and 10 for the configuration of each part.

  It is also possible to combine the individual circulation channel of the third embodiment and the circulation channel of the present embodiment. For example, an individual circulation channel is provided adjacent to a part of the first pipe L1 (or the second pipe L2), and adjacent to another part of the first pipe L1 (or the second pipe L2). Thus, it is possible to provide the circulation channel of the present embodiment across a plurality of sections. Alternatively, the circulation channel of the third embodiment can be provided on one of the first pipe L1 and the second pipe L2, and the circulation channel of the fourth embodiment can be provided on the other.

  Furthermore, the first fluid F1 that flows in the first pipe L1 and the second fluid F2 that flows in the second pipe L2 may be the parallel flow of the first embodiment, or the second fluid F2 of the second embodiment. It may be counterflow. Similarly, the flow direction of the medium in the circulation channel is also counterclockwise in the illustrated example, but can also be clockwise.

  In this embodiment, the same effect as the individual circulation channel of the third embodiment can be obtained, and the number of circulation pumps can be reduced compared to the individual circulation channel. Depending on the layout of the equipment, the total pipe length of the circulation channel It is also possible to reduce the thickness.

Further, it is possible to reduce the flow rate of the medium flowing through the circulation flow path and the pumping power as compared with the case where the circulation paths are installed in parallel. When the circulation paths are installed in parallel, the configuration 105 is as shown in FIG. Here, it should be noted that the upper and lower limits of the flow rate of the medium flowing through the heat pump are practically limited. That is, the upper limit of the flow rate is determined from the tolerance for the pressure loss of the heat pump, and the lower limit of the flow rate is determined from the viewpoint of preventing the drift of the medium flowing to the evaporator and condenser in the heat pump. Therefore, when the circulation paths are installed in parallel, the circulation flow rate cannot be less than the sum of the lower limit medium flow rates of the heat pumps. When the circulation path is installed in a single loop, the flow rate of the heat pump having the highest lower limit medium flow rate among all the heat pumps becomes the lower limit value of the circulation flow rate, and the flow rate of the medium can be reduced. For simplicity, in FIGS. 9 and 12, the capacities of the heat pumps are all the same, and the process flow rate and the temperature change in the first pipe L1 are also the same. If the medium heat exchanger upstream temperature T34 is the same, the circulation flow rate Fp in the case of parallel installation is the lower limit medium flow rate of each heat pump × 4, and the total amount of exchange heat in all heat pumps is Fp × ΔTh × (circulation medium Specific heat capacity). If T14−T10> ΔTh in the single-loop circulation path, the circulation flow rate Fs in the case of the single-loop circulation path can be Fp> Fs.
(Application example for sugar liquid purification process)
The example which applied the heat exchange system of this invention to the refinement | purification process of a sugar liquid is shown. FIG. 13 shows an example of a glucose purification process 21. The stock solution of glucose is supplied to the cation exchange resin tower 22 filled with the cation exchange resin at about 60 ° C., and the cation component contained in the stock solution is removed. The stock solution is cooled to about 42.5 ° C. in the heat exchanger 23 and supplied to an ion exchange resin tower (MB tower) 24 packed with a strongly acidic cation exchange resin and a weakly basic anion exchange resin in a mixed bed format. The cation component and the anion exchange component are removed. The stock solution is further cooled through a heat pump 25 (HP) and a cooler 26 to which chiller water is supplied, and then is supplied to a mixed-bed final stage ion exchange resin tower (MB tower) 27 for final finishing purification. As supplied, the cation component and the anion exchange component are removed. In the process so far, the temperature of the stock solution is gradually lowered in order to ensure the performance of the ion exchange resin in the ion exchange resin tower 24 and the final stage ion exchange resin tower 27, and the outlet temperature of the final stage ion exchange resin tower 27 is It is about 25 ° C. The cooled stock solution is returned to the heat exchanger 23, heat exchange is performed with the high-temperature stock solution, and the temperature is adjusted until the temperature becomes substantially the same. Thereafter, heat is exchanged by the heat pump 25, the temperature is raised, and further, the preheater 28 is heated to about 70 ° C.

  In this application example, the same stock solution (however, the degree of purification is different) is supplied to the heating side and the cooling side of the heat pump 25. That is, the pipe section from the ion exchange resin tower 24 to the cooler 26 corresponds to the first pipe L1 of the present invention, and the section from the heat exchanger 23 to the preheater 28 is the second pipe L2 section of the present invention. It corresponds. The section from the cooler 26 to the heat exchanger 23 constitutes a third pipe L3 that connects the first pipe L1 and the second pipe L2 in series. A high-temperature stock solution having a relatively low degree of purification is cooled on the evaporation side of the heat pump 25, adjusted to a desired degree of purification by the final-stage ion exchange resin tower 27, and then supplied to the condensation side of the heat pump 25. In this way, the same fluid is first supplied to the cooling side (first pipe L1) of the heat pump 25 and then supplied to the heating side (second pipe L2), so that there is no other heat source to be used. The fluid can be heated and cooled in a self-contained manner.

  Moreover, in this application example, before supplying the undiluted solution to the heating side and the cooling side of the heat pump 25, the temperature is adjusted so that the two undiluted solutions have substantially the same temperature through the heat exchanger 23. That is, when the section upstream of the first pipe L1 is the fourth pipe L4, the heat exchanger performs heat exchange between the third pipe L3 and the fourth pipe L4. As a result, the hot stock solution and the low temperature stock solution are adjusted to substantially the same temperature, and then these stock solutions are supplied to the cooling side and the heating side of the heat pump 25, respectively. It is desirable to remove heat from the high-temperature stock solution for treatment in the ion exchange resin tower 24, and it is desirable to heat the low-temperature stock solution in order to suppress energy consumption in the preheater 28. Since the temperature of the fourth pipe L4 is sufficiently higher than the temperature of the third pipe L3, heat transfer by the heat exchanger 23 is possible. In the vapor compression heat pump, the temperature of the fluid (L2, L6, etc.) after receiving heat radiation from the heat pump is lower than the temperature of the fluid (L1, L5, etc.) after the heat pump receives heat. Should be avoided. This is because it causes heat pump troubles such as poor condensation. Therefore, the heat exchanger 23 has an effect of improving the energy efficiency of the entire process and stabilizing the operation state of the heat pump.

  In addition, since the target fluid for heat exchange is basically the same undiluted solution with a different degree of purification, in the unlikely event that a leak occurs in the heat exchanger 23, even if both fluids are mixed, damage can be minimized. it can.

  In addition, the refinement | purification process of the sugar liquid to which this invention is applied should just be provided with the heat pump mentioned above at least in series, and sugar liquid flows through at least one in a 1st piping and a 2nd piping. It only has to be done.

Example 1
The temperature and flow rate of the sugar solution and the energy consumption of the heat pump were measured with the apparatus shown in FIG. Four heat pumps were arranged in series, and the glucose solution was supplied in a counterflow. In the figure, TI indicates a temperature sensor, HP indicates a heat pump, and FI indicates a flow meter. Bx (Brix sugar concentration) 30% glucose solution is stored in a tank of 5m ³ capacity and passed through the first and second pipes L1 and L2 at a flow rate of 8.2m ³ / h. The temperature of the glucose solution and the power consumption of each heat pump were measured. The first pipe L1 is a heat receiving side pipe that receives heat from the heat pump, and the sugar solution is cooled. The second pipe L2 is a heat radiation side pipe that radiates heat from the heat pump, and the sugar solution is heated. As shown in Table 1, the glucose solution was heated from 39.8 ° C. to 66.4 ° C. in the heat radiating side pipe and cooled from 44.8 ° C. to 24.8 ° C. in the heat receiving side pipe. The total power consumption of the heat pump at this time was 41.5 kW, and 8.2 m ³ / h glucose solution was processed.

As a comparative example, the temperature, flow rate, and energy consumption of the sugar solution were measured with the apparatus shown in FIG. In the comparative example, only one heat pump is provided. Other configurations and measurement conditions are the same as those in the first embodiment. The temperature changes on the heating side and the cooling side of the glucose solution were almost the same as in Example 1, although there were some differences from the Example. Specifically, as shown in Table 1, the glucose solution is heated from 40.3 ° C. to 64.1 ° C. in the heat radiation side pipe (L2), and from 45.1 ° C. to 24. 5 in the heat reception side pipe (L1). Cooled to 9 ° C. The power consumption of the heat pump at this time was 13.0 kW, and a 1.5 m ³ / h glucose solution was processed.

Here, in order to make the processing flow rates of Example 1 and the comparative example as uniform as possible, it is assumed that five heat pumps are arranged in parallel in the comparative example. The total power consumption of the heat pump at this time is 13.0 × 5 = 65.0 kW, and 1.5 × 5 = 7.5 m ³ / h glucose solution is processed. Comparing the power consumption per 1 m ³ / h of glucose, Example 1 is 41.5 kW / 8.2 m ³ /h=5.1 kW, and the comparative example is 65.0 kW / 7.5 m ³ /h=8.7 kW. Become. Therefore, Example 1 has higher energy efficiency of the heat pump than the comparative example. Furthermore, in general, the heat efficiency of the heat pump decreases as the liquid temperature on the heat radiating side and the heat receiving side become different, but Example 1 (series counterflow) has a larger liquid temperature difference in the whole system than the comparative example, and the efficiency Was expensive.

(Example 2)
The temperature of the sugar solution, the flow rate, and the energy consumption of the heat pump were measured with the apparatus shown in FIG. Five heat pumps were arranged in series, and the glucose solution was supplied in parallel flow. The reason why the five units are arranged in series is to align the temperature change of the glucose solution with that of Example 1 as much as possible. The glucose solution was heated from 39.8 ° C. to 67.0 ° C. in the heat radiation side pipe (L2) and cooled from 45.1 ° C. to 24.5 ° C. in the heat reception side pipe (L1). The total power consumption of the heat pump at this time was 54.5 kW, and 8.2 m ³ / h glucose solution was processed. When compared with the power consumption per 1 m ³ / h of glucose, Example 2 is 54.5 kW / 8.2 m ³ /h=6.6 kW, and the comparative example is 8.7 kW. Therefore, Example 2 has higher energy efficiency of the heat pump than the comparative example. The relationship between the liquid temperature difference and the energy efficiency is the same as in the first embodiment.

A Heat pump arrangement direction D1, D2 Flow direction of the first and second fluids F1, F2 First and second fluids Hx1 to Hx4 Circulation channel heat exchangers HP, HP1 to HP4 Heat pumps L1 to L4 First to second 4 piping L31-L34, L41-L44, L5, L6 Circulation flow path P31-P34, P41-P44, P5, P6 Pump S11-S14, S21-S24, S31-S36, S41-S46 Section

Claims (13)

A first pipe in which the first sugar solution is made to flow in a plurality of sections sequentially; a second pipe in which the second sugar solution is made to flow in a plurality of sections; and a plurality of heat pumps. Have
The plurality of heat pumps receive heat from at least one section of the first pipe and dissipate heat to the plurality of sections of the second pipe, or receive heat from the plurality of sections of the first pipe, respectively. A sugar solution purification system that radiates heat to at least one of the sections of the second pipe.   A single circulation channel provided between the first pipe and the plurality of heat pumps, between the second pipe and the plurality of heat pumps, or both of them; The circulation flow path is configured such that the medium sequentially flows through a plurality of sections, and the plurality of heat pumps pass between the first pipe and the second pipe through the plurality of sections of the circulation flow path. The sugar solution refining system according to claim 1, wherein the heat is transferred.   The single circulation channel is provided between the first pipe and the plurality of heat pumps, and is between at least one section on the first pipe and at least one section on the circulation channel. At least one circulation channel heat exchanger that performs heat exchange in the plurality of heat pumps, wherein the plurality of heat pumps respectively receive heat from the plurality of sections of the circulation channel and radiate heat to the plurality of sections of the second pipe. The sugar liquid purification system according to claim 2.   The single circulation channel is provided between the second pipe and the plurality of heat pumps, and is between at least one section on the second pipe and at least one section on the circulation path. At least one circulation channel heat exchanger that performs heat exchange at the plurality of heat pumps, wherein the plurality of heat pumps respectively receive heat from the plurality of sections of the first pipe and dissipate heat to the plurality of sections of the circulation channel. The sugar liquid purification system according to claim 2.   The sugar solution purification system according to claim 1, wherein the plurality of heat pumps respectively receive heat from the plurality of sections of the first pipe and dissipate heat to the plurality of sections of the second pipe.   A plurality of circulation passages provided between the first pipe and the individual heat pumps, and a plurality of circulation passage heats for exchanging heat between the first pipe and the individual circulation passages. The sugar solution refining system according to claim 1, further comprising: an exchanger, wherein the plurality of heat pumps respectively receive heat from the circulation channels and dissipate heat to the plurality of sections of the second pipe. .   A plurality of circulation passages provided between the second pipe and the individual heat pumps, and a plurality of circulation passage heats for exchanging heat between the second pipe and the individual circulation passages. The sugar solution purification system according to claim 1, further comprising: an exchanger, wherein the plurality of heat pumps respectively receive heat from the plurality of sections of the first pipe and dissipate heat to each of the circulation channels. .   The sugar solution purification according to any one of claims 1 to 7, wherein the first sugar solution and the second sugar solution flow in directions opposite to each other with the plurality of heat pumps interposed therebetween. system.   The sugar solution purification system according to any one of claims 1 to 7, wherein the first sugar solution and the second sugar solution flow in the same direction with the plurality of heat pumps interposed therebetween.   The first or second sugar solution that has a third pipe that connects the first pipe and the second pipe in series, and that has flowed out of one of the first pipe and the second pipe The sugar solution purification system according to any one of claims 1 to 9, wherein the sugar solution purification system is configured to flow into the other of the first pipe and the second pipe through the third pipe. .   Heat exchange for exchanging heat between the fourth pipe connected to the upstream pipe of the first pipe and the second pipe, and the third pipe and the fourth pipe. A sugar solution purification system according to claim 10, comprising:   An ion exchange resin tower is further provided on the third pipe, and the sugar solution is supplied to the fourth pipe, cooled by the heat exchanger, supplied to the first pipe, and cooled by the heat pump. The sugar solution purification system according to claim 11, supplied to the third pipe, purified by the ion exchange resin tower, and further heated by the heat exchanger through the third pipe. A method of exchanging heat between a first pipe in which a first sugar solution is made to flow in a plurality of sections sequentially and a second pipe in which a second sugar solution is made to flow in a plurality of sections sequentially Because
The plurality of heat pumps receive heat from at least one section of the first pipe and dissipate heat to the plurality of sections of the second pipe, or receive heat from the plurality of sections of the first pipe. A method for refining a sugar solution, comprising radiating heat to at least one of the sections of the second pipe.

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