JP2007333278A - Evaporator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaporator capable of the efficient heat exchange requiring only a simple outside air entrance preventing mechanism, and capable of controlling the energy consumption when the device is operated. <P>SOLUTION: A bypass line Lc with a flow regulating valve (a bypass valve 21) branches (B3) from a steam line which communicates with the outlet side of a steam compressor 2 and a steam condenser 3. The bypass line Lc joins (B1) a steam line which communicates with a drying container 1 and the intake side of the steam compressor 2. The pressure inside the drying container 1 (e.g. the pressure difference between the pressure inside the drying container 1 and the atmospheric pressure) is set at the same level as the atmospheric pressure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to energy saving in a concentration and drying process involving evaporation and dehydration, and more particularly to an evaporation apparatus that compresses water vapor and recovers and uses condensation latent heat (heat of vaporization).

Evaporative dehydration such as concentration and drying has a problem that a large amount of energy is consumed and operation cost is high due to the large latent heat of vaporization of water (2258 kJ / kg at 100 ° C.).
In order to solve this problem, there is a technology for increasing the saturation temperature by increasing the water vapor generated in the evaporation and dehydration process, exchanging heat with the material to be dried, condensing, recovering and using this latent heat, and using it for the subsequent evaporation and dehydration. Exists. Such a technique is called vapor recompression (VRC) or mechanical vapor compression (MVR). In this specification, this technique is denoted as “VRC”.

  In principle, VRC can be widely applied to processes involving evaporation and dehydration, and exhibits a large energy saving effect. However, the conventional technology is limited to the concentration of a solution or the like that can be easily exchanged with heat. There are no practical examples of. VRC is a well-known technology, but it is difficult to say that it is widely known, and there are few materials describing the details of the technology.

  The wort concentrator (see Non-Patent Document 1) based on the VRC technique in FIG. 25 is heated at 100 ° C. at atmospheric pressure by heating water with a steam boiler (not shown) or the like, and the generated steam is compressed by the compressor 110. Increase the pressure to about 3.2 atm. This water vapor is heat-exchanged with the wort in the wort boiling pot 130 by the heater 120, condensed at 136 ° C to recover the latent heat of condensation, and the condensed water is discharged as drain water. The COP (coefficient of performance) obtained by dividing the recovered heat by the compressor power is 7. The wort is structured to circulate and heat with the pump 140.

The wort concentration apparatus in FIG. 25 is an apparatus that evaporates and concentrates the water content of wort by about 10%.
Since the boiling pot 130 has low pressure resistance and it is necessary to maintain atmospheric pressure in order to meet conventional boiling conditions, the top of the boiling pot 130 is open to the atmosphere. In order to prevent air from entering the boiling pot 130, the amount of water vapor generated in the boiling pot 130 needs to be larger than the amount of suction of the compressor 110. In order to discard this excess water vapor to the outside air, Loss occurs.
That is, the wort concentrator in FIG. 25 needs to maintain the relationship of “water vapor generation amount> compressor intake amount” in order to prevent the intrusion of outside air, and excess water vapor is cooled and discarded. The loss of is great.

When the amount of water vapor generated is smaller than the amount sucked by the compressor 110, the pressure inside the boiling pot 130 becomes lower than the atmospheric pressure and air enters. Since air does not condense (noncondensable), the pressure of the heater 120 becomes high, the compression power increases and COP is remarkably lowered, and there is a risk of overloading the compressor 110.
In addition, if water vapor | steam is discharge | released as it is, the problem of a white smoke and an odor will arise, Therefore It is the structure which heat-exchanges with cooling water in the heat exchanger 150, and condenses water vapor | steam.

The prior art shown in FIG. 26 is an evaporation apparatus that performs continuous treatment using a helical auger-shaped heat exchanger for the purpose of drying particulate matter (see Patent Document 1).
The dryer shown in FIG. 26 includes three pipes 200, 202, and 204, and the inside is shielded from the outside air.
In such an airtight dryer, the pressure inside the dryer is different from the atmospheric pressure, so if the internal pressure is higher than atmospheric pressure, it will prevent steam from blowing out, and if the internal pressure is lower than atmospheric pressure, it will prevent air from entering. A structure is needed.

In FIG. 26, the inside of the intermediate chamber 230 and the intermediate chamber 240 is evacuated by the liquid ring pump 236 using special sealing devices 232, 206, 234, 242, 246, etc. at the entrances and exits of the dryers 200, 202, 204. The structure is illustrated. However, such an entrance / exit air intrusion prevention structure is complicated and causes an increase in manufacturing cost.
Furthermore, if the object to be dried has adhesiveness, the adhered object to be dried causes a rotation with the spiral auger, so that the object to be dried and the transfer of heat to the object to be dried (heat exchange) are not good. It is expected to be possible.

As another conventional technique, a rotary stirring water vapor condenser of a dry container having an airtight structure has been proposed (for example, Patent Document 2, Patent Document 3, Patent Document 4, Patent Document 5, Patent Document 6, Patent Document 7, (See Patent Document 8, Patent Document 9, Patent Document 10, Patent Document 11, and Patent Document 12).
The drying container of Patent Document 2 has an airtight structure, and the pressure inside the drying container is operated in a vacuum state below atmospheric pressure as a matter of course. In the vacuum operation, since it becomes difficult to input the material to be dried and to discharge the dried material, batch (batch) processing is assumed.

That is, the prior art of Patent Document 2 is a batch processing method and does not assume continuous processing. Batch processing has a problem that the manufacturing cost of the apparatus is high because the drying container becomes large and the drying container needs to be designed and manufactured with a strength that can withstand vacuum.
As described in Patent Document 2, in VRC, when a gas that does not condense together with water vapor (non-condensable gas) such as air or carbon dioxide gas is mixed, it becomes a resistance when water vapor condenses and condensation heat transfer coefficient. Is significantly reduced. And if a condensation heat transfer rate falls remarkably, a condensation pressure will raise and there exists a problem which increases the motive power of a water vapor compressor.

In addition, non-condensable gas may be present inside the device at the start of operation, or may be exposed to voids in the material to be dried or water dissolved during operation, or may leak into the device. To do. For this reason, it is necessary to always discharge noncondensable gas.
For this reason, in Patent Document 2, a discharge valve for non-condensable gas is provided at the outlet of the steam condenser. However, this structure is insufficient in extracting the air retained in the steam condenser.

The inventor performs trial manufacture and experiment based on such a series of conventional techniques (invention of Patent Document 2 and the following), and publishes the result as a research and development paper (see Non-Patent Document 2).
JP 58-158485 A Japanese Patent No. 3681049 Japanese Patent No. 3147142 Japanese Patent No. 3209322 Japanese Patent Laid-Open No. 10-103861 Japanese Patent No. 3147146 Patent 309776 Japanese Patent No. 3685477 JP 2001-153545 A JP 2002-147951 A JP 2005-288320 A United States Patent 5 987,770 Energy Conservation Center, July 26, 1991, p. 117- "Industrial heat pump" Kashima Technical Research Institute Annual Report No. 50, September 30, 2002, pp. 151-156, “Research and Development of Energy-Saving Evaporative Dehydration Technology”

  The present invention has been proposed in view of the above-described problems of the prior art, can simplify the outside air intrusion prevention mechanism, enable efficient heat exchange, and can suppress energy consumption during operation. The purpose is to provide an evaporation device.

  According to the prototype and experiment conducted by the inventor (see Non-Patent Document 2), it has been demonstrated that energy consumption and accompanying carbon dioxide emissions can be reduced to a fraction of those compared to conventional drying technology. . Furthermore, in FIG. 4, the higher the boiling (evaporation) temperature, the higher the condensed water discharge rate (that is, the drying capacity). 5 shows that the smaller the difference between the steam condensation temperature and the boiling temperature (temperature increase range), the higher the COP (coefficient of performance: the value obtained by dividing the water evaporation latent heat by the power consumption of the steam compressor). ing.

  The evaporation apparatus of the present invention is a development of the inventor's trial production and experiment, and includes the contents of the drying container (1), the steam compressor (2), and the drying container (1) (the object to be dried). And an evaporator (water vapor) having a water vapor condenser (3) in heat exchange relation with the water vapor line communicating with these devices (drying vessel 1, water vapor compressor 2, water vapor condenser 3, water vapor generating means 7) In the compression-type evaporator, a bypass is provided via a flow rate adjustment valve (bypass valve 21) from a steam line (11a, 11b, 11c) that communicates the discharge side of the steam compressor (2) and the steam condenser (3). The line (Lc) is branched (B3), and the bypass line (Lc) joins the steam lines (10a, 10b, 10c) that communicate the drying container (1) and the suction side of the steam compressor (2). (B1) and dry container ( ) (For example, the pressure difference between the inside of the drying container 1 and the atmospheric pressure) (22) is provided (in the drying container 1 and / or the water vapor line 11), and a flow rate adjusting valve (bypass valve 21). ) To control the pressure (Pe) in the drying container (1) to increase the set value (P2: the amount of steam supplied from the steam boiler 7), the pressure Pe in the drying container 1 cannot be increased. The pressure or threshold value is characterized in that the pressure or threshold value is not lowered below, for example, -3 kPa in gauge pressure (Claim 1).

Here, it is preferable to provide a steam generation means (steam boiler 7).
Alternatively, instead of providing the steam generating means (steam boiler 7), a heating device (for example, an electric heater 200) is provided in the drying container (1), and the drying container (1) is provided by the heating device (200). The to-be-dried material thrown into the inside can be heated to generate water vapor (see FIG. 6).

  The evaporation apparatus control method of the present invention is the same as the above-described evaporation apparatus (water vapor compression evaporation apparatus: evaporation apparatus according to claim 1), wherein the pressure in the drying container (1) is controlled by the pressure detection means (22). Pe: For example, the step (S2) of detecting the pressure difference between the drying container 1 and the atmospheric pressure), and the detected pressure (Pe) in the drying container (1) is set to a set value (P2: from the steam boiler 7). The pressure (P6) in which the pressure Pe in the drying container 1 cannot be increased even if the water vapor supply amount is increased or a threshold (for example, −3 kPa in gauge pressure) is compared with the step (S6) in the drying container (1). A step (S7) of increasing the opening of the flow regulating valve (bypass valve 21) when the pressure (Pe) is lower than the set value (P2) (Claim 12: FIG. 12). 3).

  The evaporation apparatus of the present invention includes a drying container (1), a steam compressor (2), a steam condenser (3) in a heat exchange relationship with the contents (substance to be dried) of the drying container (1), In an evaporator (water vapor compression evaporator) having a water vapor line communicating with a device such as a drying container 1, a water vapor compressor 2, a water vapor condenser 3, and a water vapor generating means 7) A bypass line (Lc) with a flow rate adjusting valve (bypass valve 21) branches (B3) from a steam line (11a, 11b, 11c) that communicates the side and the steam condenser (3). The line (Lc) merges (B1) with the water vapor lines (10a, 10b, 10c) that connect the drying container (1) and the suction side of the water vapor compressor (2), and discharges the water vapor compressor (2). Detect pressure (Pc) in pipe (11) Pressure detection means (pressure sensor 23) is provided, the flow rate adjustment valve (bypass valve 21) is controlled, and the pressure (Pc) of the discharge pipe (11) of the steam compressor (2) is set to a set value (P3: overload, etc.) The pressure or threshold value that may cause the inoperable state of the vehicle is set so as not to be higher than the pressure or threshold (for example, 100 kPa as a gauge pressure) (Claim 2).

Also in this case, it is preferable to provide a water vapor generating means (water vapor boiler 7).
Alternatively, instead of providing the steam generating means (steam boiler 7), a heating device (for example, an electric heater 200) is provided in the drying container (1), and the drying container (1) is provided by the heating device (200). Water to be dried can be generated by heating the material to be dried.

  The evaporation apparatus control method of the present invention is the same as the above-described evaporation apparatus (water vapor compression evaporation apparatus: evaporation apparatus according to claim 2), in which the water pressure compressor (2) is controlled by the pressure detection means (pressure sensor 23). A step of detecting the pressure (Pc) of the discharge pipe (11) (S11) and a step of comparing the pressure (Pc) of the discharge pipe (11) of the water vapor compressor (2) with the set value (P3) (S12). And increasing the opening of the flow rate adjustment valve (bypass valve 21) when the pressure (Pc) of the discharge pipe (11) of the steam compressor (2) is higher than the set value (P3) (S13), (Claim 13).

  The evaporation apparatus of the present invention includes a drying container (1), a steam compressor (2), a steam condenser (3) in a heat exchange relationship with the contents (substance to be dried) of the drying container (1), In an evaporation device (water vapor compression evaporator) having a water vapor line communicating with a device such as a drying vessel 1, a water vapor compressor 2, a water vapor condenser 3, and a water vapor generating means 7, the water vapor condenser (3a) A plurality of rotors (steel pipe coiled coils or so-called “squirrel rod-like rotors”) are arranged in parallel, and the rotors are made of steel pipes. It is characterized by being arranged so as to rotate while intersecting so as not to interfere (claim 3).

  Also in this case, it is preferable to provide a steam generating means (steam boiler 7), or instead of providing the steam generating means (steam boiler 7), a heating device (for example, an electric type) is provided in the drying container (1). It is preferable that a heater 200) is provided, and the object to be dried put into the drying container (1) is heated by the heating device (200) to generate water vapor.

Here, it is preferable that the rotor is formed in a coiled coil shape around a steel pipe.
Alternatively, the linear steel pipe (31a) is composed of a plurality of linear steel pipes (tubes 31a), and each of the linear steel pipes (31a) is a rotating shaft (the central axis of the rotor, which is entirely configured in a so-called “squirrel rod” shape). ) In parallel with each other, arranged radially outwardly of the rotating shaft and at equal intervals in the circumferential direction, and each of the straight steel pipes (31a) is connected to the rotating shaft by a hollow support member (33). It is preferable to communicate with the passage (hole 32eh) provided (the whole is configured in a so-called “squirrel cage” shape) (Claim 5).
In such a configuration, for example, the rotor includes a central steel pipe (trunk portion 32a) disposed coaxially with the rotation axis, and a central steel pipe (32a) disposed radially outward of the central steel pipe (32a). A plurality of steel pipes (tubes 31a) arranged in parallel, the plurality of steel pipes (31a) are arranged at equal intervals in the circumferential direction, and each of the plurality of steel pipes (31a) is a hollow support material ( 33) is preferably supported by a central steel pipe (32a).
Alternatively, in such a rotor, the central steel pipe (32a) can be omitted.

The steam condenser (3) is configured by arranging a plurality of stages (main condenser 3a, sub-condenser 3b) in series, and communicates with the last-stage steam condenser (sub-condenser 3b). Preferably, a non-condensable gas discharge valve is provided.
More specifically, a non-condensable gas discharge connection port and a line (non-condensable gas discharge pipe 27) communicating with the final stage water vapor condenser (sub-condenser 3b) are provided. A discharge valve (5) for noncondensable gas is preferably provided in the discharge pipe 27).

Here, the gas (mixture of non-condensable gas and water vapor) flowing through the non-condensable gas discharge line (non-condensable gas discharge pipe 27) is brought into direct contact with the object to be dried (6) and preheated ( It is preferable that the heat recovery be performed (Claim 7: FIG. 14).
Alternatively, a heat exchanger (19) is provided in a mechanism (input port 8) for charging the material to be dried (6), and a line for discharging noncondensable gas (noncondensable gas discharge pipe) is provided in the heat exchanger (19). 27) a gas (mixture of non-condensable gas and water vapor) flowing through 27) is introduced, and a part of the enthalpy (condensation latent heat and sensible heat) of the gas (mixture of non-condensable gas and water vapor) is transferred to the heat. It is preferable that the material to be dried (6) is introduced through the exchanger (19) (Claim 8: FIG. 15).

In the present invention, the water vapor generating means (7) can be configured to use the exhaust heat of the internal combustion engine (E) as a heat source (FIG. 16).
Alternatively, the water vapor generating means (7) is configured to be heated by an electric heater (30, H), and the hot water temperature in the water vapor generating means (7) is maintained at a temperature near the boiling point (100 ° C.) at atmospheric pressure. It is preferable to be configured as described above (Claim 9: FIGS. 7 and 17).

Further, in the present invention, the drying container (1: or the steam condenser 3, 3a) is provided to be inclined with respect to the horizontal plane, and the mechanism (input port 8) for charging the material to be dried (6) is the material to be dried. It is preferable that it is located below the mechanism (discharge port 9) for discharging (6).
Furthermore, if this inclination is made variable, it can be adjusted according to the fluidity of the material to be dried, and can be used for drainage during internal cleaning.

  In the present invention, it is provided in any position (for example, the sub-condenser 3b) from the steam compressor (2) to the outlet of the steam condenser (3), and the discharge system and the suction system of the drying container (1). It is preferable to have a steam pipe (LP9) communicating with the inside of the gate valve (9).

The control method of the present invention is the above-described control method of the evaporator of the present invention (the evaporator according to any one of claims 1 and 2), wherein the flow rate adjusting valve (21) of the bypass line (Lc) is set at the start of operation. It is preferable to have a step of opening (circulating air or a mixed gas of air and water vapor to the bypass line Lc: step S22) and raising the temperature inside the water vapor compressor (2) (claim 14).
Here, the step (S22) is preferably continued until a predetermined time elapses from the start of operation or until the temperature inside the compressor (2) is increased to a predetermined temperature.

  According to the present invention having the above-described configuration, the pressure inside the drying container (1) is determined from the balance between the amount of water vapor generated from the object to be dried (6) and the amount of water vapor sucked by the water vapor compressor (2). When the amount of water vapor generated from the material to be dried (6) is larger than the amount of water vapor sucked by the water vapor compressor (2), the pressure increases, and when the reverse is true, the pressure decreases. Thereby, in the evaporation apparatus of the present invention, when the pressure inside the drying container (1) is lower than the set value (P2), that is, even if the amount of steam supplied from the steam boiler (7) is increased, the drying container Even when the pressure (Pe) in (1) is reduced to a level where it cannot be increased (for example, when the gauge pressure is lower than -3 kPa), the bypass line (Lc) of the steam compressor (2) The flow rate adjustment valve (bypass valve 21) is increased, the amount of water vapor sucked by the compressor (2) is reduced, and the pressure inside the drying container (1) is recovered (increased). As a result, the pressure inside the drying container (1) can be maintained at the same level as the atmospheric pressure.

  In the present invention, the pressure inside the drying container (1) is always kept close to atmospheric pressure by adjusting the opening of the flow rate adjustment valve (bypass valve 21) of the bypass line (Lc) of the steam compressor (2). As a result, it is possible to supply the object to be dried (6) and discharge the dried substance while minimizing the intrusion of outside air or the jet of steam to the outside, so even if continuous processing is performed. The inlet (8) and the outlet (9) can have a simple airtight structure. In the case of batch processing, of course, steam ejection can be suppressed.

  And in this invention, since the pressure inside a dry container (1) can always be kept near atmospheric pressure, the pressure resistance of a dry container (1) can be eased. In particular, when batch processing is performed, it is necessary to enlarge the drying container (1). As preparation for abnormal pressure exceeding the setting, a pressure relief valve (vacuum breaker, safety valve 15 or the like) may be provided.

Furthermore, in the present invention, since the pressure inside the drying container (1) can always be kept close to atmospheric pressure, the capacity and operating efficiency of the steam compressor (2) are improved as compared with the vacuum operation. This is because the density of water vapor is increased, for example, 70kPa steam 0.42 kg / ^{m 3} (sat temperature 90 ° C.) is a 0.60 kg / ^{m 3} at 101 kPa (saturation temperature 100 ° C.), about 40% In the case of a positive displacement compressor, the capacity increases almost at this ratio.

In addition to this action, the abnormal pressure rise of the steam condenser (3) is avoided by adjusting the opening of the flow rate adjusting valve (bypass valve 21) of the bypass line (Lc) of the steam compressor (2). I can do it.
That is, in the present invention, the pressure (Pc) of the discharge pipe (11) of the steam compressor (2) is detected by the pressure detection means (pressure sensor 23), and the pressure of the discharge pipe (11) of the steam compressor (2) is detected. If the opening degree of the flow rate adjustment valve (bypass valve 21) is increased when (Pc) is higher than the set value (P3), the water vapor discharged from the compressor (2) will flow into the flow rate adjustment valve (bypass valve 21). ) Is returned to the suction side of the compressor (2) via the bypass line (Lc) in which it is interposed, and is sucked into the compressor (2) again. That is, the water vapor discharged from the compressor (2) is not supplied to the condensers (3, 3a) but returns to the suction side of the compressor 2 via the bypass line Lc. The discharge pressure can be released.

  Thus, when the pressure on the discharge side (condenser 3 or the like) of the water vapor compressor (2) rises abnormally, the pressure can be released using the bypass valve (21). It is possible to prevent overcurrent and breakage of the motor due to overload of the compressor due to an abnormal rise in pressure on the condenser 3 side). At the same time, it is not necessary to discharge the compressed gas from the compressor (2) to the outside of the evaporator, so that it is very useful particularly when a gas having a strong odor is used.

The flow rate adjustment valve (bypass valve 21) of the bypass line (Lc) is highly effective in heating (preheating) operation that prevents water vapor from condensing inside the water vapor compressor (2).
In the present invention, prior to the dehydration operation, if the flow rate adjustment valve (bypass valve 21) is opened and the discharge side of the compressor (2) is bypassed to the suction side, the compressor (2) is discharged. Since air is again sucked into the compressor (2) through the bypass line (Lc), the internal temperature of the compressor (2) can be raised while preventing excessive mixing of water vapor. Thereby, at the time of start-up, air containing a large amount of water vapor is sucked into the compressor (2) while the compressor (2) is cold, and the water vapor is condensed (condensed) inside the compressor 2, The risk of damage due to compression or erosion can be prevented.

  If the present invention is applied, the inside of the drying container (1) can be maintained at an arbitrary pressure. For example, it is possible to control the internal pressure of the drying container (1) for the purpose of manipulating the temperature of the evaporative dehydration process for the purpose of preventing alteration or for the purpose of fractionating volatile substances. In this case, it is preferable to use an absolute pressure sensor for the pressure sensor (22).

Here, the screw conveyor (spiral auger) as seen in the conventional example (Patent Document 2) is originally intended for transport of materials and is not necessarily suitable as a heat exchanger for drying. . The reason is as follows.
First, because the fin efficiency of the screw part is low and it is not effective as an enlarged heat transfer surface, the heat transfer area is insufficient.
Second, it is difficult to measure the matching (balance) between the transportation capacity and the drying capacity.
Third, it is difficult to secure a passage for the generated water vapor.
Fourth, the material may adhere to the screw portion and be carried around.
Fifth, because a special technique is required for production, the production cost increases.

  As the water vapor condenser (3, 3a) used in the present invention, if a coiled coil water vapor condenser (3a) or a steel tube cage water vapor condenser (3a) is used, the stirring and The structure is suitable for heat exchange with the heat of vaporization of water vapor flowing inside. In addition, it is possible to optimize the rotation speed of the steam condenser from the viewpoint of energy efficiency.

  Moreover, since the total extension of the steel pipe can be lengthened, the heat transfer area can be increased and the heat of condensation can be reliably input to the material to be dried. As a result, it is also possible to remove moisture from the material to be dried in a dryer from a highly water-containing liquid state to a dried solid state.

  Moreover, since it is a multi-shaft type and it is a structure which meshes | engages without mutual steel pipes contacting, the quantity which a to-be-dried material adheres to the condenser (3a) surface and deposits can be reduced. Thereby, the state where the relative position between the water vapor condenser (3a) and the object to be dried does not change, that is, so-called “circulation” is avoided, and the effect of preventing the heat exchange capacity from being lowered is also exhibited.

In the present invention, if the steam condenser (3) has a multi-stage configuration (main condenser 3a, sub-condenser 3b) and is arranged in series, the final stage steam condenser (sub-condenser 3b) contains non-condensable gas. By providing the discharge valve (5), the non-condensable gas can be prevented from staying in the main steam condenser (main condenser 3a), and the heat exchange capacity can be prevented from lowering.
On the other hand, the condenser (subcondenser 3b) other than the main steam condenser (main condenser 3a) increases the ratio of the non-condensable gas and improves the function of the steam vent valve (5). effective.

  Exhaust gas from the non-condensable gas discharge valve (5), that is, gas (mixture of non-condensable gas and water vapor) flowing through the non-condensable gas discharge line (non-condensable gas discharge pipe 27) If the amount of heat to be generated is input to the object to be dried (6), it is possible to recover and use all of the latent heat of the water vapor that comes out with the non-condensable gas such as air.

  In order to input the amount of heat held by the gas (mixture of non-condensable gas such as air and water vapor) flowing through the non-condensable gas discharge line (non-condensable gas discharge pipe 27) to the object to be dried (6). For example, if the gas (mixture of non-condensable gas such as air and water vapor) is brought into direct contact with the object to be dried (6), the object to be dried (6) having voids will have a drying container (1). This has the effect of expelling the non-condensable gas that has accumulated in the air gap before being supplied to.

  Further, in the present invention, the water vapor generating means (7) is configured to be heated by the electric heater (30, H), and the temperature of the hot water in the water vapor generating means (7) is a temperature near the boiling point (100 ° C.) at atmospheric pressure. (FIGS. 7 and 17), if the pressure Pe in the drying container 1 is reduced to an atmospheric pressure or lower, the pressure in the water vapor generating means (boiler 7) is also increased in the drying container (1). The pressure is reduced following the pressure (Pe), and the temperature of the hot water in the water vapor generating means (boiler 7) exceeds the boiling point, so that water vapor is immediately generated, and the pressure in the drying container 1 returns to atmospheric pressure. Therefore, it is not necessary to measure the pressure (Pe) in the drying container (1) and compare it with the atmospheric pressure.

In the present invention, the drying container (1: or the steam condenser 3, 3a) is provided to be inclined with respect to the horizontal plane, and the mechanism (input port 8) for charging the material to be dried (6) is the material to be dried ( 6) If it comprises so that it may be located below the mechanism (discharge port 9) which discharges, even if the moisture content of a dried object (6) is high and fluidity is large, the dried object is The weight remains below and does not move to the upper discharge mechanism (discharge port 9) side.
Therefore, it is prevented that the material to be dried reaches the discharge mechanism (discharge port 9) without being sufficiently dehydrated and is discharged from the drying container (1).

In addition, if a moisture detection sensor is provided in the vicinity of the discharge mechanism (discharge port 9) and the supply device for feeding the material to be dried (6) is controlled (for example, the number of rotations of the screw feeder 14 is controlled), the target moisture is obtained. Can be dried to quantity.
Here, if the inclination angle of the drying container (1) is configured to be adjustable, it can be handled from a material with high fluidity (slurry) to a material with low fluidity (granular). Of course, the inclination angle of the drying container (1) may be variable.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, a first embodiment of the present invention will be described with reference to FIG.

In FIG. 1, an evaporation apparatus denoted as a whole by reference numeral 100 has water vapor held in a dry container 1 having an insulated structure, a compressor 2 that compresses a gas such as water vapor, and an object to be dried 6 in the dry container 1. A steam condenser 3 for supplying heat of condensation and a steam boiler 7 are provided.
Here, in the water vapor condenser 3, the water vapor charged with the amount of heat held in the object to be dried 6 is condensed into warm water (liquid phase, drain).

  Although the simplified expression is shown in FIG. 1, the drying vessel 1 has a structure in which the water vapor condenser (double jacket) is formed into a hollow wall, and a rotating stirring with a number of tubes as a water vapor condenser inside the drying vessel 1. The structure to be used can be used. Details will be described from the fourth embodiment onward in FIG.

The dry container 1 is formed with a dry matter input port (input port) 8 for charging the dry matter 6 into the container, and a dry matter discharge port (discharge port) 9 for discharging the dried product. .
The drying container 1 and the compressor 2 are connected by a suction pipe 10 (a pipe communicating with the suction side of the compressor 2). The compressor 2 and the condenser 3 are connected by a discharge pipe 11 (a line on the discharge side of the compressor 2).
The steam condenser 3 is connected to a discharge line Lx that discharges condensed water and non-condensable gas accumulated in the condenser 3 to the outside of the condenser 3. The steam trap 4 and a steam vent valve are connected to the discharge line Lx. 5 (non-condensable gas discharge valve) is interposed.

The suction pipe 10 includes a line 10a from the drying container 1 to the junction B1, a line 10b from the junction B1 to the junction B2, and a line 10c from the junction B2 to the suction side of the compressor 2. . The line La from the steam boiler 7 joins the joining point B2.
On the other hand, the discharge pipe 11 is composed of a line 11a from the compressor 2 to the branch point B3, and a line 11b from the branch point B3 to the water vapor condenser 3.

The steam boiler 7 has a role for start-up heating (preheating) at the time of startup and for additional cooking heating at the time of operation.
The steam generated in the steam boiler 7 is supplied to the suction side (low pressure side: low pressure side steam supply valve 12a, line 10c side) of the compressor 2. In other words, the steam boiler 7 communicates with the suction side of the compressor 2 via the branch point B2 and the line 10c via the line La provided with the steam supply valve 12a.

The junction B1 of the suction pipe 10 and the branch point B3 of the discharge pipe 11 are connected by a bypass line Lc with a flow rate control valve (bypass valve) 21 interposed therebetween.
In order to perform flow rate control (valve opening degree control) of the flow rate adjustment valve 21, the pressure sensor 22 is provided in the drying container 1, and the pressure sensor 23 is provided in the discharge pipe 11.
The pressure sensor 22 is provided to detect a differential pressure between the pressure inside the drying container 1 and the atmospheric pressure. Specifically, a differential pressure sensor, a compound type (coupled type: for both positive pressure and negative pressure) gauge pressure sensor, or the like is used. Here, the absolute pressure sensor may be used to measure the inside of the drying container 1 and the atmospheric pressure separately, and calculate the differential pressure.

FIG. 2 shows a modification of the first embodiment.
In the first embodiment shown in FIG. 1, the steam boiler 7 is connected to the suction side of the compressor 2 via a branch point B2 via a line La interposed with a steam supply valve 12a. On the other hand, in the modification of FIG. 2, the steam boiler 7 communicates with the junction B <b> 4, that is, the discharge side of the compressor 2 via the line Lb interposing the steam supply valve 12 b. Therefore, in the modification of FIG. 2, the water vapor generated in the water vapor boiler 7 is supplied to the discharge side (high pressure side: the water vapor supply valve 12b, the lines 11b and 11c side) of the compressor 2. In other words, the steam boiler 7 communicates with the discharge side of the compressor 2 via a line Lb having a steam supply valve 12b interposed.

Further, according to the modification of FIG. 2, only the suction pipe 10 from the drying container 1 communicates with the suction side of the compressor 2, and no confluence is provided on the suction side of the compressor 2.
Other configurations of the modified example of FIG. 2 are the same as those of the first embodiment of FIG.

The pressure control of the evaporator 100 shown in FIG. 1 or FIG. 2 will be described.
The pressure control in the evaporation and dehydration operation is performed by detecting the pressure inside the drying container 1 with the sensor 22, outputting a control signal from the control means (control unit) 50 to which the detection signal of the sensor 22 is input, This is done by adjusting the opening. Although not shown, the pressure sensor 22 may be installed not only in the drying container 1 but also in the suction pipe 10.
In FIG. 1, reference symbol Li indicates an input signal line, and reference symbol Lo indicates a control signal line.

Next, control in the first embodiment and its modification will be described with reference to FIGS.
As described above, in the evaporation apparatus of the present invention, batch (batch) processing or continuous processing may be used. In the evaporator 100 of FIGS. 1 and 2, for example, when a dehydration operation of continuous processing is performed, when a raw material having a low temperature (a material to be dried) is input, the pressure in the drying container 1 is suddenly reduced.
First, with reference to FIG. 3, the pressure control when the pressure in the drying container 1 suddenly decreases will be described.

In FIG. 3, it is determined whether or not the dehydration operation is performed in the evaporator 100 of FIGS. 1 and 2 (step S1), and when the dehydration operation is not performed (step S1 is NO), FIG. The control shown is not performed ("END" in FIG. 3).
When the dehydration operation is being performed (YES in step S1), the pressure Pe in the drying container 1 is measured by the pressure sensor 22 (step S2), and the pressure Pe in the drying container 1 is compared with the set value P1. (Step S3).
Here, the set value P1 is, for example, atmospheric pressure, that is, P1 is 0 kPa (G) if it is a gauge pressure, and if it is absolute pressure, P1 is 101 kPa (abs) if it is standard atmospheric pressure. The water saturation temperature at the set value P1 is about 100 ° C.

If the pressure Pe in the drying container 1 is higher than a set value P1 (for example, atmospheric pressure) (Yes in step S3), the amount of steam supplied from the boiler 7 is reduced so that the pressure in the drying container does not increase. Therefore, the opening degree of the water vapor supply valve 12a is decreased by one step (step S4). Then, the process returns to step S1.
Here, the opening for one step is determined on a case-by-case basis. In the case of the modification of FIG. 2, the opening degree of the water vapor supply valve 12b is decreased by one step.

When the pressure Pe in the drying container 1 is equal to or lower than a set value P1 (for example, atmospheric pressure) (step S3 is No), in order to increase the pressure inside the drying container, to increase the amount of steam supplied from the boiler 7, The opening degree of the water vapor supply valve 12a (12b in the case of FIG. 2) is increased by one step (step S5).
Here, basically, the opening of the steam supply valve 12a (12b in the case of FIG. 2) is increased, and the opening of the steam flow rate adjusting valve 12a from the boiler 7 is increased, whereby the inside of the drying container 1 is increased. The pressure Pe is restored.

  When adding steam from the steam boiler 7 to the suction side of the compressor 2 (FIG. 1), the shortage of the amount of steam generated from the material to be dried 6 is compensated, and when adding to the discharge side (FIG. 2), the steam condenser 3 Since the amount of water vapor supplied to the water to be dried increases, the heat of condensation input to the material to be dried 6 also increases, and the amount of water vapor generated from the material to be dried 6 increases. As a result, in any case, the pressure inside the drying container 1 is increased.

Here, when adding water vapor to the suction side, the shortage of water vapor generated from the material to be dried is directly compensated. Therefore, while the pressure drop can be followed in seconds, the power boosted by the compressor 2 is increased. Consume. Further, when the steam generation pressure of the boiler 7 is as low as atmospheric pressure to about 100 kPa, it is necessary to apply to the suction side of the compressor 2.
On the other hand, if the steam of the boiler 7 is added to the discharge side of the compressor 2, no compression power is required, but the amount of steam generated increases after heat is transferred from the steam condenser 3 to the material 6 to be dried. The pressure cannot be increased over time. The steam generation pressure of the boiler 7 needs to be sufficiently higher than the discharge pressure of the compressor 2.
Both can be used by taking advantage of the advantages of adding the steam of the boiler 7 to the suction side of the compressor 2 and adding it to the discharge side.

In this way, the pressure Pe in the drying container 1 can be increased by increasing the opening of the valve 12a (12b) and increasing the amount of steam supplied from the boiler 7, but the valve 12a (12b) There is a case where the pressure in the drying container 1 is not sufficiently recovered by increasing the opening. Step S6 and subsequent steps in FIG. 3 are controls corresponding to such a case (when the pressure in the drying container 1 is not sufficiently recovered by increasing the opening degree of the valves 12a and 12b).
After the opening degree of the water vapor supply valve 12a (12b) is increased by one step in step S5, the pressure Pe in the drying container 1 is compared with the set value P2 (step S6). Here, the set value P2 is a pressure at which the pressure in the drying container 1 is considered not to be sufficiently recovered by increasing the opening of the valves 12a and 12b. For example, if the gauge pressure is −3 kPa (G) and the absolute pressure is set. When the atmospheric pressure P0 is 101 kPa (abs), P2 is 98 kPa (abs).

When the pressure Pe in the drying container 1 is higher than the set value P2 (gauge pressure is −3 kPa) (Yes in step S6), the pressure in the drying container 1 is recovered by increasing the opening degree of the valves 12a and 12b. Then, the process returns to step S1.
When the pressure Pe in the drying container 1 is equal to or lower than the set value P2 (−3 kPa as a gauge pressure) (No in step S6), the pressure in the drying container 1 is recovered by increasing the opening of the valves 12a and 12b. It judges that it does not carry out, the opening degree control of the flow control valve 21 (bypass valve) is performed (step S7), and then it returns to step S1.

  As for the opening degree control in step S7, as will be described later, when the pressure Pe in the drying container 1 is not more than the set value P2 (gauge pressure: -3 kPa) (step S6 is No), the flow rate control valve The opening degree of the (bypass valve) 21 is increased, and the water vapor discharged from the compressor 2 is returned to the suction side of the compressor 2 via the bypass line Lc. Since the water vapor discharged from the compressor 2 is sucked into the compressor 2, the amount of water vapor sucked in the drying container 1 by the compressor 2 can be reduced, so that the pressure inside the drying container 1 (for example, It recovers (to atmospheric pressure).

  In other words, in the flowchart of FIG. 3, the minute pressure drop in the drying container 1 is dealt with by increasing the amount of steam supplied from the steam boiler 7 as described in steps S2, S3, and S5. . And the pressure drop which cannot be coped with by the increase in the amount of steam supplied from the steam boiler 7 is dealt with by opening control of the flow control valve 21 (bypass valve).

  Here, the control method of the control unit 50 is not limited. Although feedback control is common, modern control, fuzzy control, and next-generation control using feedforward control, artificial intelligence, or the like can also be used.

When step S3 in FIG. 3 is Yes, when the pressure in the drying container 1 rises above the atmospheric pressure, an active means for reducing the pressure is not necessary. The reason is that the temperature of the drying container 1 is higher than about 100 ° C. and higher than room temperature (usually about 25 ° C.), and even if it is insulated, heat dissipation cannot be completely prevented, and thus the temperature tends to gradually decrease. . And if the temperature of the drying container 1 falls, the internal pressure will also fall.
In the case of continuous processing, when a new object to be dried enters, the temperature decreases and the saturated water vapor pressure also decreases, so the pressure in the drying container 1 decreases.
Therefore, basically, it is only necessary to have means for preventing the pressure inside the drying container 1 from decreasing.

The steam condenser 3 is operated at a pressure higher than atmospheric pressure (for example, 0 to 100 kPa as a gauge pressure). However, when drying of the object to be dried 6 progresses and heat transfer becomes worse, or when non-condensable gas such as air stays in the steam condenser 3, the discharge pressure of the compressor 2 increases abnormally. May become impossible to drive. As a countermeasure, when the pressure sensor 23 is interposed on the discharge side of the compressor 2 and it is detected by the detection signal of the pressure sensor 23 that the pressure of the condenser 3 has risen abnormally, the flow control valve 21 The opening degree can be increased to control the pressure on the high pressure side (discharge side) to escape to the low pressure side (suction side).
The flowchart of FIG. 4 shows such control.

4, steps S1 and S2 are the same as those in FIG. When the dehydrating operation is being performed (YES in step S1), the discharge pressure Pc of the compressor 2 is measured by the pressure sensor 23 (step S11). Then, the compressor discharge pressure Pc measured by the pressure sensor 23 is compared with the set value P3 (step S12).
Here, the set value P3 is a threshold value as to whether or not the discharge pressure of the compressor 2 is abnormally increased and becomes inoperable. For example, the gauge pressure is 100 kPa (G), and the absolute pressure P0 is 101 kPa. In the case of (abs), it is 201 kPa (abs).

If the discharge pressure Pc of the compressor 2 is lower than the set value P3 (Yes in step S12), it is determined that the compressor 2 is not overloaded, and the process returns to step S1.
If the discharge pressure Pc of the compressor 2 is higher than the set value P3 (step S12 is No), it is determined that the compressor 2 is in an overload state. In that case, the opening degree control of the flow rate adjustment (bypass) valve 21 is performed (step S13), and the process returns to step S1.

  That is, when there is a possibility that the discharge pressure of the compressor 2 may rise abnormally and become inoperable, the water vapor discharged from the compressor 2 is bypassed by the bypass lines Lc and 10b if the flow rate adjustment (bypass) valve 21 is opened. Then, it returns to the suction side of the compressor 2 through the junction B2 and the line 10c and is sucked into the compressor 2 again. As a result, when the pressure in the discharge pipe 11 rises, the water vapor discharged from the compressor 2 is returned to the suction side of the compressor 2 via the bypass line Lc, so that the discharge pressure of the compressor 2 is increased. I can escape.

  The adjustment of the suction amount of the compressor 2 may be performed together with the capacity control of the compressor 2. The motor-driven compressor can change the rotation speed by an inverter. When the engine is driven, the number of revolutions can be changed by adjusting the throttle opening.

  The disadvantage of the method of adjusting the pressure by opening the flow rate adjusting valve 2 (bypass valve) is that the compressor 2 is caused to perform useless work and is accompanied by energy loss. Therefore, in order to minimize useless work by the compressor 2, the flow control valve (bypass valve) 21 is normally closed and the dehydration operation is performed, and the flow control valve (bypass valve) 21 is opened by a drying container. What is necessary is just to recover the pressure in the condenser 3 when recovering the pressure in 1 in a short time, when raising the temperature of the compressor 2 or preheating the material to be dried prior to the dehydration operation, etc. .

The opening degree control of the flow rate control valve 2 (bypass valve) in FIGS. 3 and 4 will be further described.
3 and 4, if the pressure Pe in the drying container 1 and the discharge pressure Pc of the compressor 2 are measured (step S2 in FIG. 3 and step S21 in FIG. 4), the pressure Pe in the drying container 1 and the above-mentioned The set value P2 is compared, and the discharge pressure Pc of the compressor 2 is compared with the set value P3 described above (step S3 in FIG. 3 and step S12 in FIG. 4).

  If the pressure Pe in the drying container 1 is higher than the set value P2 and the discharge pressure Pc of the compressor 2 is lower than the set value P3 (Pe> P2andPc <P3), the pressure in the drying container 1 It is determined that Pc is not lowered to an extent that the steam supply valve 12a (12b) is not recovered by an increase in opening degree, and that there is no possibility of operation failure due to an abnormal increase in the discharge pressure of the compressor 2, The flow rate adjustment valve 21 (bypass valve) is closed, and the gas discharged from the compressor 2 does not flow through the bypass line Lc.

In other cases, that is, in the case of Pe <P2 and / or Pc> P3, the pressure Pc in the drying container 1 that has decreased to such an extent that it cannot be recovered by increasing the opening of the steam supply valve 12a (12b) is recovered. And / or in order to release the discharge pressure of the compressor 2 to the suction side and reduce it, the flow control valve 21 (bypass valve) is opened to a predetermined opening.
Here, the predetermined opening degree of the flow control valve 21 (bypass valve) is the pressure difference between the pressure Pe in the drying container 1 and the set value P2, or the pressure difference between the discharge pressure Pc of the compressor 2 and the set value P3. Due to other reasons, it is set on a case-by-case basis. In an actual machine, it is determined by, for example, a map stored in the control unit 50.

  Next, an example of control of the flow rate adjustment valve 21 (bypass valve) at the start of operation will be described with reference to FIG.

If water vapor is condensed (condensed) inside the compressor 2, the compressor 2 may be damaged by liquid compression in a positive displacement compressor and by erosion in a centrifugal compressor. In order to prevent this, it is necessary to increase the temperature inside the compressor 2 (for example, to 100 ° C. or higher) at the start of operation.
In the control shown in FIG. 5, when starting the dehydration operation (Yes in Step S <b> 21), the compressor 2 is operated, and the flow rate adjustment (bypass) valve 21 is controlled to set the flow rate of the bypass pipe Lc to an intermediate or maximum. The timer 60 provided in the control unit 50 is activated (step S22).
If the timer 60 counts that a predetermined time has elapsed (Yes in step S23), the timer 60 stops timing and closes the flow rate adjustment (bypass) valve 21 (step S24).

If the flow rate control (bypass) valve 21 is controlled so that the flow rate of the bypass pipe Lc is set to the middle or maximum, the bypass flow rate control valve 21 is opened at the start stage of the dehydration operation (the time when step S23 is No). 2 is operated, and the inside of the compressor 2 is effectively circulated in a closed system such as the discharge port of the compressor 2, the line 11a, the bypass line Lc, the line 10b, the line 10c, and the suction port of the compressor 2. The temperature can be raised.
When the temperature inside the compressor 2 rises, the water vapor does not condense (condense) inside the compressor 2, and therefore the compressor 2 is damaged by liquid compression in the positive displacement compressor and erosion in the centrifugal compressor. This is prevented.

  Here, the bypass flow rate adjustment valve 21 is opened and the compressor 2 is operated, and air is discharged in a closed system including the discharge port of the compressor 2, the line 11 a, the bypass line Lc, the line 10 b, the line 10 c, and the suction port of the compressor 2. As for the circulation time (time when step S23 is No), the elapsed time is measured by the timer 60 in FIGS. 1 and 5, but the temperature inside the compressor 2 is measured, and the internal temperature of the compressor 2 is water vapor. Alternatively, the bypass flow rate control valve 21 may be closed when the temperature becomes sufficiently higher than the condensing temperature.

Although the control of the embodiment shown in FIGS. 1 to 5 has been described, it is not limited to the control described above.
For example, the atmospheric pressure changes depending on the atmospheric pressure change due to the weather or the altitude above the sea level of the installation location. In the case of standard atmospheric pressure (1013 hPa, that is, 101.3 kPa), the boiling point of water is almost 100 ° C., but the normal atmospheric pressure (local pressure) does not necessarily become 100 ° C.
When the atmospheric pressure is 90 kPa, the boiling point of water is about 97 ° C, when the atmospheric pressure is 90 kPa, and when the local pressure is 105 kPa, such as when the atmospheric pressure is low, the boiling point of water is about 101. It becomes ℃.

  Although the pressure inside the drying container 1 is regarded as the saturated vapor pressure of water, the saturated vapor pressure changes when there is a dissolved substance. For example, if sugar is dissolved, the saturation pressure decreases, and if alcohol is dissolved, it evaporates and the saturated vapor pressure increases. Further, when air or the like remains in the drying container 1, the partial pressure is applied.

It is also conceivable to use a temperature sensor instead of the pressure sensor 22. However, as described above, the pressure inside the drying container 1 may not be estimated from the temperature, and if the temperature sensor is used, the local atmospheric pressure cannot be corrected. For this reason, a pressure sensor is preferable to a temperature sensor.
However, if the change in the local atmospheric pressure can be ignored, the amount of dissolved matter in the water is small, and control accuracy is not required, a temperature sensor can be used instead of the pressure sensor.

  As an input to the control unit 50, auxiliary sensors can be used in addition to the pressure sensor 22 described above. For example, it is also possible to enhance the control by using signals such as temperature, compressor motor current, and timer.

  If the pressure in the drying container 1 rises abnormally due to an unexpected situation such as a control failure, the water vapor can be released to the outside of the container using a safety valve (see reference numerals 15 and 16 in FIG. 14).

  The means for heating the object to be dried 6 is not limited to the combination of the steam boiler 7 and the condenser 3. For example, the drying container 1 can be directly heated by circulating an electric heater or pressurized hot water.

  In the illustrated embodiment, the compressor 2 uses an oil-free type that does not use cylinder lubricating oil. As the type of the compressor 2, there are a centrifugal type, an axial flow type, a screw type, a reciprocating type, a swing type, a roots type, a scroll type, a rotary type, and the like, and the capacity control method varies depending on the type of the compressor 2. For example, the centrifugal type includes guide vane control, the screw type includes slide valve control, and the reciprocating type includes cylinder number control.

According to the first embodiment (FIG. 1) having the above-described configuration (FIG. 1) and its modification (FIG. 2), the pressure in the drying container 1 is maintained at or near atmospheric pressure, and the inlet 8 and outlet 9 The reduction in temperature and pressure due to the supply of the material to be dried 6 can be quickly recovered.
Therefore, 1st Embodiment (FIG. 1) and its modification (FIG. 2) show the characteristics in the continuous process of VRC evaporation dehydration (vapor recompression; refer to background art).

In FIG. 1, the steam boiler 7 is provided as the steam generating means. However, as shown in FIG. 6, an electric heater 200 (heating device) is provided in the drying container 1, and the commercial power source 202 is connected via the power supply line 204. Thus, the heater 200 may be configured to be heated. If comprised in this way, the to-be-dried material thrown in in the drying container 1 can be heated, and water vapor | steam can be generated.
In FIG. 6, reference numeral 12 c is a heating amount adjusting device for the heater 200.

Next, a second embodiment will be described with reference to FIGS.
FIG. 7 shows the configuration of the second embodiment. The steam boiler 7 has an electric heater 30, and the electric heater 30 is connected to a power source 32. Here, the electric heater 30 is configured to control the temperature so that the hot water in the boiler 7 is kept at 100 ° C. Reference numeral 31T indicates a temperature sensor.

  In FIG. 7, if the pressure Pe in the drying container 1 is reduced to an atmospheric pressure or lower, the pressure in the boiler 7 is also reduced following the pressure Pe in the drying container 1. If the hot water in the boiler 7 is kept at 100 ° C., the hot water temperature in the boiler 7 exceeds the boiling point if the pressure in the boiler 7 decreases following the pressure Pe reduction, so the hot water in the boiler 7 immediately Vaporization generates water vapor. As a result, the amount of water vapor supplied from the boiler 7 increases, and the pressure in the drying container 1 returns to atmospheric pressure as described above with reference to FIGS.

In other words, according to the second embodiment of FIG. 7, when the pressure Pe in the drying container 1 drops below the atmospheric pressure, steam is generated in the boiler 7 and supplied to the suction side of the compressor 2. Therefore, it is not necessary to perform the valve opening control of the water vapor supply valves 12a and 12b as in the first embodiment of FIGS.
Therefore, in FIG. 8 showing the control when the pressure Pe in the drying container 1 decreases in the second embodiment, if the pressure Pe in the drying container 1 is measured (step S2), the pressure Pe in the drying container 1 Is compared with a pressure (−3 kPa in terms of gauge pressure) at which the pressure in the drying vessel 1 is considered not to be sufficiently recovered only by increasing the set value P2, that is, the amount of steam supplied from the boiler 7 (step S6). Steps corresponding to steps S3 to S5 in FIG. 3 do not exist in FIG.

  Other configurations and operational effects in the second embodiment shown in FIGS. 7 and 8 are the same as those in the embodiment shown in FIGS.

FIG. 9 shows a third embodiment of the present invention.
In FIG. 9, the steam boiler 7 communicates with the suction side of the compressor 2 via the branch point B2 via the line L and the line La provided with the branch point B5 and the low-pressure side steam supply valve 12a. In addition, it communicates with the discharge side of the compressor 2 via the junction B4 via the line L and the line Lb interposing the branch point B5 and the high-pressure side steam supply valve 12b.

As in the third embodiment of FIG. 9, the steam boiler 7 is communicated with both the suction side and the discharge side of the compressor 2 to finely control the start-up heating at start-up and the additional cooking during operation. Is possible.
About another structure and an effect, it is the same as that of embodiment of FIGS. 1-8 and its modification.

Next, the structure of the water vapor condenser 3 used in the illustrated embodiment will be described.
As a continuous process of VRC drying, in the prior art, a technique using a heat exchanger using a spiral auger is disclosed (see Patent Document 1).
However, the heat exchanger using a helical auger has various problems as described below.

  First, as described in FIG. As shown in FIG. 5, in order to increase the energy efficiency (COP) of the VRC method, it is necessary to reduce the difference (temperature increase width) between the steam condensation temperature and the temperature of the object to be dried. For example, the temperature increase width of 15K is about 1/4 of that of a conventional conduction heating type evaporator, and in order to realize this, it is necessary to increase the heat transfer area by about four times.

  Second, in the spiral auger (screw conveyor) of Patent Document 1, water vapor flows through the hollow shaft, but the heat exchange area of this portion is small. Although the screw portion becomes a heat exchange fin, the effect as an expanded heat transfer surface is small in combination with the thin wall thickness compared to the height and the low thermal conductivity of stainless steel.

  Thirdly, because of the relationship between the drying capacity and the screw conveyor transport capacity, the heat transfer rate to the material to be dried is low because the rotating speed is extremely low.

  Fourth, screw conveyors are expensive because they are manufactured by welding screws to a shaft, and the purpose of reducing the cost and increasing the heat transfer area is not suitable.

  Fifth, water vapor evaporated from the material to be dried flows into the suction pipe of the compressor. This water vapor has a large specific volume due to its low pressure (1.7 m3 / kg or more), and pressure loss during flow must be reduced because it causes performance degradation, but this is achieved with the prior art (Patent Document 1). Can not. (Since the gap between the spiral auger and the tube that accommodates it is small, water vapor flows while blowing the material to be dried on the spiral blade).

  Sixth, in the drying operation, the adherence of the material to be dried becomes a serious problem. In the spiral auger, the material to be dried adheres to the spiral (screw) part and is carried around, and there is a possibility that neither transportation nor heat exchange is possible. Although patent document 1 makes the object a granular material, even if it is a granular material, it often shows adhesiveness in a wet state.

  Seventh, with the above-described conventional technology, it is difficult to balance the transportation capacity and the drying capacity. Drying is an operation that requires several hours or more, and since the processing capacity per unit time is small, the screw conveying capacity is usually excessive. As a countermeasure for this, it is conceivable to make the pitch of the screw extremely small. However, the manufacturing cost increases, and if the rotational speed is extremely reduced, the heat exchange capability is lowered. Furthermore, in order to cope with a change in moisture content, the rotational speed of the entire spiral auger must be changed.

In view of the problems of the prior art as described above, in the illustrated embodiment, the steam condenser 3 is improved as shown in FIGS. 10 to 13 and FIGS. 18 to 20.
Next, with reference to FIGS. 10-13, the detailed structure of the water vapor | steam condenser 3 (code | symbol 3a in 4th Embodiment-7th Embodiment) in embodiment of this invention is demonstrated.

As shown in FIG. 10, the steam condenser 3 a used in the illustrated embodiment is a steel pipe (for example, a stainless steel pipe) formed into a spiral coil shape (referred to as a spiral coil; reference numeral 31), and two sets thereof. , And are configured to rotate in a crossed state without contacting each other.
A rotation shaft 32 is provided at the center position of the helical coil 31. As shown in detail in FIGS. 11 and 12, a large number of hollow spoke-like support members (hollow spokes) 33 that connect the tubular shaft 32 and the helical coil 31 are provided. The rotation of the tubular shaft 32 is transmitted to the coil 31, and water vapor and condensed water are circulated.

In FIG. 11, plug members 32b are provided at both ends of the shaft 32, and both ends in the longitudinal direction of the inner diameter portion of the shaft main body 32a are closed by the plug members 32b. In the plug member 32b, a projecting portion 32c is formed at the center portion on the opposite side to the shaft main body 32a, and a through hole 32d is formed at the center of the projecting portion 32c.
In the example of FIG. 11, two pitches are supported by solid spokes 34 for every three pitches of the spiral winding, and hollow spokes 33 are arranged in front of (or behind) the solid spoke members 34.
In FIG. 11, water vapor is supplied from the left plug member 32b to the shaft main body 32a, and the supplied water vapor flows through the shaft main body 32a, the hollow spoke 33, and the helical coil 31, and is condensed by any of them.

When the water vapor is condensed, the volume is reduced to about 1/600 at 100 ° C., so that the water vapor flows from the shaft 32 to the helical coil 31 in order to supplement the volume.
Referring to FIG. 12, the water condensed in the helical coil 31 is pumped up by the handle-like structure 33a at the tip of the hollow spoke 33, and the condensed water pumped up is rotated by the helical coil 31 (arrow R). Is lifted upward and flows to the shaft body 32a by gravity.

The condensed water W flows through the bottom of the shaft body 32a, but the end 33b of the hollow spoke 33 is the center (in the shaft body 32a) radially inward of the shaft body 32a so that it does not flow back to the helical coil 31. Protrudes into the area.
In the shaft 32 and the hollow spoke 33, the water vapor condenses while heating the material 6 to be dried.

Referring to FIG. 11, the condensed water W (FIG. 12: not shown in FIG. 11) in the helical coil 31 accumulates in the lower part of the helical coil 31, and this condensed water is generated by the rotation of the helical coil 31. It moves to the right, is lifted even by the rightmost hollow spoke member 33, moves to the shaft body 32a, and flows out from the right plug member 32b of the shaft body 32a.
As described above, all the spokes do not have to be hollow tubes, and a solid spoke member 34 that transmits rotational torque may be used in combination as shown in FIGS.

FIG. 13 is a modification of FIG.
In FIG. 13, the inside of a hollow spoke 33 </ b> A through which water vapor and condensed water flow is divided into two by a partition 33 </ b> Ac, and the condensed water is lifted by the rotation of the helical coil 31 and flows to the shaft 32.
As described above, as the spoke members of FIGS. 11 to 13, the flow path (hollow) 33, 33 </ b> A and the solid spoke 34 for structure (for supporting the helical coil 31) are prepared, and the majority is structured. As the solid spoke 34, the hollow spokes 33 and 33A for the flow path need only be arranged at an appropriate interval in consideration of the flow rate.

If the water vapor condenser 3a having the above-described configuration is used, the water vapor is condensed not only inside the shaft 32 but also inside the helical coil 31 through heat exchange with the material to be dried 6 (FIG. 1). Large heat transfer area.
In addition, the helical coil-shaped flow path can ensure a large total length, and water vapor can be condensed, that is, moisture can be reliably removed from the object to be dried.
Furthermore, the screw by the helical coil 31 is aimed at the heat transfer capacity of stirring rather than the transport capacity, and the heat transfer coefficient by sliding between the coil surface and the object to be dried can be increased by setting the required rotation speed. it can.

  In the illustrated embodiment, the helical coil 31 can be manufactured at low cost by a pipe bender using a steel pipe (stainless steel pipe) that has been mass-produced.

  Further, since the helical coil 31 has a structure with many gaps, when the water vapor generated from the overheated material flows upward and laterally (in the direction of the inlet of the suction pipe 10 of the drying container 1c), it becomes a resistance. There is little fear of it.

In the helical coil 31 of FIGS. 10 to 13, if the minimum gap between the two sets of coils 31 and 31 and the minimum gap between the coil 31 and the shaft 32 are set to about 10 mm, for example, the material to be dried adheres. When the thickness of the adhesion layer exceeds a predetermined value, a mutual scraping action due to rotation occurs, and an action of removing the object to be dried adhering to the surfaces of the coil and the shaft occurs (self-cleaning).
If removal of deposits is insufficient, add fats and oils to the material to be dried, or apply a peeling coating (Teflon (registered trademark), etc.) to the surface of the coil or shaft to promote removal of deposits You can also

In the example of FIG. 10, an example is shown in which coils that are reversely wound are rotated in different directions with a biaxial (twin) screw, but coils that are wound in the same direction may be rotated in the same direction.
Furthermore, a multi-axis screw provided with three or more coils or shafts can be configured while having the above-described configuration.

Next, based on FIG. 14, 4th Embodiment of this invention is described. In FIG. 14, the entire evaporator is denoted by reference numeral 101.
The fourth embodiment in FIG. 14 uses the basic configuration of the evaporator 100 in FIG. 1 and the configuration of the water vapor condenser 3a described in FIGS.
14, parts similar to those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

In FIG. 14, the evaporator 101 is arranged such that the casing 1 c of the drying container 1 is inclined. The steam condenser 3 includes a main steam condenser (main condenser) 3a disposed in an inclined casing 1c, and a sub steam condenser (sub-condenser) provided adjacent to the lower portion of the casing 1c like a casing jacket. Instrument) 3b.
By adjusting the inclination angle of the drying container 1, it is possible to handle a material with high fluidity (slurry) to a material with low (granular) material.

  In FIG. 14, a protrusion 1d is formed on the upper right side of the casing 1c. The area | region is divided by the filter 17 between the protrusion part 1d and the inside of the casing 1c except the protrusion part 1d.

  A to-be-dried material input hopper (input port) 8 is formed above the left end of the casing 1 c, and the lower end of the input port 8 is connected to the suction port 14 a of the screw feeder 14. The discharge port 14b of the screw feeder 14 is connected to the upper left end 1ci of the casing 1c. A dry matter discharge valve 9 is provided at the lower right end of the casing 1c.

The coil 31 of the main condenser 3a has the same configuration as that of the biaxial helical coil 31 described with reference to FIGS. 10 to 13. However, FIG. Only the helical coil 31 of the book is shown.
In the example of FIG. 14, the two helical coils 31 (see FIGS. 10 to 13) are rotated so that the right end of the shaft 32 that supports the coils 31 rotates at a low speed of about 10 rotations per minute by the motor 13 with a reduction gear. It is configured.

Rotor joints (rotating joints) 18 are provided at both ends of the shaft 32 so that water vapor and condensed water generated in the main condenser 3a can flow.
In FIG. 14, the rotary joint 18 at the right end of the shaft 32 is connected to the discharge pipe 11c, and the rotary joint 18 at the left end of the shaft 32 is connected to an inlet 3bi of a sub-condenser 3b described later.

  As shown in FIG. 14, the drying container (1) is provided to be inclined with respect to the horizontal plane, and a mechanism (loading port 8) for charging the material to be dried (6) discharges the material (6) to be dried. It is located below the mechanism (discharge port 9). The inclination angle of the drying container (1) with respect to the horizontal plane, in other words, the gradient of the helical coil 31 and the casing of the main condenser 3a (part of the casing of the drying container 1) 1c takes into account the fluidity of the object to be dried. Is set.

For example, when the fluidity of the material to be dried is high (when the slurry-like material to be dried is dried), the inclination angle is set to be large so that the moisture content is high and the fluidity is large, It is configured such that it remains below by weight and does not move to the upper outlet 9 side. With such a configuration, it is possible to prevent the material to be dried from reaching the discharge port 9 without being sufficiently dehydrated and being discharged from the drying container 1.
Depending on the moisture content of the material to be dried, the inclination angle may be adjustable (the inclination angle is variable).

In order to relieve excessive pressure, a first safety valve 15 is attached to the drying container 1, and a second safety valve 16 is provided on the discharge pipe 11 (line 11 c) of the compressor 2. A vacuum breaker (vacuum control valve) (not shown) may be provided.
The control unit 50 (FIG. 1) and control signal flow are omitted in FIG.

The main condenser 3a of the helical coil 31 is more suitable for stirring and heat exchange than for transporting the material to be dried.
If the number of rotations of the helical coil 31 is increased, the heat transfer coefficient of the surface can be increased, but the power of the electric motor 13 is increased. On the other hand, if the rotational speed of the electric motor 13 is lowered, the consumed power is reduced, but the heat transfer coefficient is lowered. Taking this into consideration, the rotational speed of the helical coil steam condenser 3a is set so as to optimize the energy efficiency.

In the fourth embodiment shown in FIG. 14, the material 6 to be dried is charged into the charging port 8 and supplied to the drying container 1 by the screw feeder 14.
The supply amount of the screw feeder 14 is controlled with the target value of the moisture amount at the outlet of the dried product discharge valve 9 being controlled, and the material to be dried dried by the main condenser 3a is pushed out to the discharge valve 9. Sent. For this reason, the filling rate inside the drying container 1 becomes high, and the heat exchange capability of the main condenser 3a becomes large.

Here, when non-condensable gas such as air is mixed, it becomes a hindering factor or resistance of condensation heat transfer, increasing the condensation pressure, and increasing the compression power in the VRC evaporation dehydration, making it impossible to operate in the worst case. Sometimes.
In particular, in continuous processing, gas dissolved with the supply of the material to be dried and air present in the voids of the material to be dried are mixed, so that noncondensable gas is excluded from the water vapor condenser and discharged outside the system. Is a big challenge.

In the water vapor condenser 3 having a one-stage configuration as shown in FIG. 1, the volume is not reduced when the water vapor is condensed and the volume is reduced to about one thousandth instead of being condensed while flowing in one direction. It flows like water is rushed to fill (fill) the minute. And condensed water is discharged | emitted by rotation of the coil which is not shown in FIG.
However, non-condensable gas such as air stays in the condenser 3 and inhibits condensation of water vapor in the condenser 3.

In order to solve the situation where the condensation of water vapor in the condenser 3 is hindered by the non-condensable gas, in the fourth embodiment of FIG. 14, as described above, the water vapor condenser is multi-staged (in FIG. 14, two stages: 3a, 3b), the main condenser 3a, which is the first stage, is used exclusively for heat exchange (condensation latent heat of steam is introduced into the material to be dried), and the sub condenser 3b, which is the second stage, is not condensed. It is used for the purpose of exhausting gas.
That is, FIG. 14 is an embodiment in which the helical coil steam condenser 3a is a main condenser, and a sub jacket double steam steam condenser 3b is provided downstream thereof.

The purpose of the sub-condenser 3b is to forcibly withdraw a mixed gas of water vapor and non-condensable gas in order to prevent the retention of non-condensable gas in the main condenser 3a, to further condense the water vapor and recover latent heat, It is to increase the ratio of air.
The non-condensable gas inlet 3bi of the sub-condenser 3b is formed substantially at the center in the longitudinal direction of the sub-condenser 3b. On the other hand, the non-condensable gas discharge port 3bo of the sub-condenser 3b is formed at the right end in the longitudinal direction of the sub-condenser 3b in FIG.
In the sub-condenser 3b, a condensed water discharge port 3bw for discharging condensed water generated by condensation is formed at the left end in the longitudinal direction of the sub-condenser 3b in FIG.

As described above, the steam condenser 3 is configured in series in multiple stages (main condenser 3a, sub-condenser 3b), and the main condenser is provided with the non-condensable gas discharge valve 5 in the final stage sub-condenser 3b. It is possible to prevent the non-condensable gas from staying in 3a and to avoid a decrease in heat exchange capacity due to this.
And in the gas discharged | emitted by opening the air vent valve 5 by the subcondenser 3b, the ratio of non-condensable gas is raised.

The non-condensable gas outlet 3bo is connected to one end of a non-condensable gas discharge pipe 27 having a steam air vent valve 5 in the middle thereof. The other end 27 e of the noncondensable gas discharge pipe 27 is open to the inside of the inlet 8.
One end of a condensed water discharge pipe 28 having a steam trap 4 interposed in the middle is connected to the condensed water discharge port 3bw. The other end 28 e of the condensed water discharge pipe 28 communicates with the heat recovery device 19 that surrounds the periphery of the inlet 8.
That is, the non-condensable gas is discharged from the steam vent valve 5 together with the water vapor, and the condensed water is discharged from the steam trap 4.

  Here, even if the ratio of the non-condensable gas in the gas discharged from the steam vent valve 5 is increased, the non-condensable gas and the water vapor cannot be completely separated. For example, the molar ratio of the mixed gas of non-condensable gas and water vapor at an absolute pressure of 170 kPa and 100 ° C. is about 90% of water vapor and 10% of non-condensable gas. As a result, the heat of water vapor is lost. The evaporator 101 of the fourth embodiment collects and uses this heat.

In FIG. 14, the non-condensable gas discharge pipe 27 is opened (27 e) inside the inlet (hopper) 8, and the amount of heat held by the gas flowing through the non-condensable gas discharge pipe 27 directly Pre-heated by contact. Heat exchange (preheating) according to such an embodiment is effective.
Further, when there is a gap in the material to be dried to be preheated, there is an effect of expelling a part of the non-condensable gas such as air existing in the gap before the supply to the drying container 1.

On the other hand, the condensed water discharged from the condensed water discharge pipe 28 provided with the steam trap 4 is warm water close to 100 ° C. In order to recover the heat held by the condensed water, in the fourth embodiment, the inlet (hopper) 8 for supplying the material to be dried is used as a heat recovery device 19 having a double wall structure, and the condensed water is allowed to flow through this, It is configured to preheat the material to be dried.
Water condensed by preheating the material to be dried by the heat recovery unit 19 is discharged out of the system from a drain port 29 provided near the upper end of the heat recovery unit 19.

The steam generated in the steam boiler 7 is supplied to the junction B4 of the discharge pipe 11 on the discharge side (high pressure side) of the compressor 2 through a line Lb having a high pressure side steam supply valve 12b.
The bypass line Lc in FIG. 14 does not directly bypass the discharge pipe 11 and the suction pipe 10 as shown in FIG. However, in FIG. 14, one end of the suction pipe 10 communicates with the protrusion 1 d of the drying container 1, and if the protrusion 1 d is regarded as a part of the suction pipe 10, a layout similar to that of FIG. Become.

  In the region of the suction pipe 10 on the compressor 2 side, an outside air introduction valve 24 for drying the inside of the compressor 2 is provided before the compressor 2 is stopped. In the discharge pipe 11, an exhaust valve 25 is interposed in a region between the pressure sensor 23 and the junction B4.

Next, a mode of operation of the evaporation apparatus 101 according to the fourth embodiment in FIG. 14 will be described.
When the evaporator 101 is started, the water vapor compressor 2 is started with the bypass valve 21 open. Therefore, the air discharged from the discharge port of the compressor 2 is sucked from the suction port of the compressor 2 through the line 11a, the branch point B3, the line Lc, the protruding portion 1d, and the line 10. Then, when the temperature inside the compressor 2 is sufficiently raised, water vapor is introduced from the boiler 7. At this time, since the internal temperature of the water vapor compressor 2 is sufficiently high, there is no possibility that water vapor will condense inside the compressor (such as a cylinder).

  In other words, when the bypass valve 21 does not exist, since the inside of the drying container 1 is evacuated when the compressor 2 is started, a high degree of airtightness and pressure resistance are required. In addition, when the compressor 2 is started when the bypass valve 21 is not present, the water vapor from the boiler 7 is sucked, so that the water vapor condenses inside the compressor 2 and breakage due to liquid compression or erosion due to liquid droplets occurs. .

  On the other hand, by opening the bypass valve 21, the discharge port of the compressor 2 reaches the suction port of the compressor 2 via the line 11a, the branch point B3, the line Lc, the protruding portion 1d, and the line 10. By circulating air in the closed path, the inside of the compressor 2 can be effectively heated (preheated). In addition, it is an advantage that the line 10 can be preheated simultaneously. When the temperature of the line 10 is low, water vapor condenses in the line 10 and the compressor 2 sucks this condensed water, which may cause damage.

  Here, if the filter 17 is provided in the vicinity of the water vapor outlet of the protruding portion 1d of the drying container 1 and the bypass line Lc is connected, the cleaning action of the filter 17 is caused by the flow and pulsation from the compressor 2.

When the operation of the evaporator 101 proceeds and the object to be dried is heated, water vapor is generated, and the water vapor partial pressure (ratio) in the mixed gas of air and water vapor in the drying container 1 is increased. Further, when the temperature of the object to be dried rises to near 100 ° C., the amount of water vapor generated from the object to be dried becomes balanced with the suction amount of the compressor 2, and the output of the pressure sensor 22 in the drying container 1 is set to a set value ( For example, when the gauge pressure reaches -3 kPa), the bypass valve 21 is closed.
In the main condenser 3a, the water vapor is condensed by supplying latent heat of condensation to the material to be dried, and the condensed water vapor (condensed water) is discharged via the sub-condenser 3b and the line L28. Since air does not condense, it is discharged from the steam vent valve 5.
Thus, the dehydration operation is gradually started.

In normal dehydration operation, the bypass valve 21 is fully closed.
The water vapor generated in the drying container 1 is pressurized by the compressor 2 and supplied to the condenser 3a, and when it is condensed by the main condenser 3a and the sub-condenser 3b, latent heat (heat of vaporization) is recovered, It is used for heating the material to be dried.
Here, the boiler 7 is reheated depending on heat loss from the entire apparatus and heating of the newly supplied material 6 to be dried. The steam supply valve 12 and the bypass valve 21 are controlled in opening degree so as to maintain the pressure inside the drying container 1 near atmospheric pressure.

When the pressure inside the drying container 1 decreases for some reason, the opening degree of the bypass valve 21 is increased, and the decrease in pressure is quickly recovered.
Further, when the pressure on the condenser 3 side abnormally rises for some reason, this is detected by the pressure sensor 23 interposed in the discharge pipe 11 and the bypass valve 21 is opened. The safety valve 15 opens in an emergency such as a control failure.

The dried product after the drying process is discharged from the discharge valve 9. Since the pressure inside the drying container 1 is maintained near atmospheric pressure, the dry matter discharge valve 9 can use a simple structure, such as a rotary valve, as compared with the prior art (Patent Document 1). .
Regarding the inlet 8 of the material 6 to be dried, a sealing (material seal) effect by the material to be dried itself and a slurry pump or the like when the material has fluidity can be considered. Design and manufacture will take into account the properties of the material and the accuracy of pressure control.

At the end of the dehydration operation, the supply of the material to be dried 6 is stopped, and the residue inside the drying container 1 is dried. At that time, since the heat transfer is deteriorated, the pressure of the main condenser 3a rises. This can also be dealt with by the opening degree control of the bypass valve 21.
Prior to stopping the compressor 2, outside air is passed to dry the inside of the compressor 2. For this purpose, the outside air introduction valve 24 and the exhaust valve 25 are opened at the same time, but if it is left as it is, a large amount of air will flow, resulting in a loud noise. For this, the amount of outside air introduced can be adjusted by controlling the opening of the bypass valve 21.

  When the object to be dried 6 is directly preheated using the gas flowing through the non-condensable gas discharge pipe 27, there is a possibility that the water vapor contained in the gas is condensed and the moisture of the object to be dried 6 is increased. An evaporating apparatus that addresses such fears is shown in the fifth embodiment of FIG.

The fifth embodiment will be described with reference to FIG.
In FIG. 15, the entire evaporator is indicated by reference numeral 102.
In FIG. 15, portions different from the fourth embodiment of FIG. 14 will be mainly described.

  In FIG. 15, the steam boiler 7 communicates with the protruding portion 1 d of the drying container 1 through a line La interposed with a low-pressure side steam supply valve 12 a. That is, in terms of layout, the pipe La from the steam boiler 7 is connected to the suction side of the compressor 2.

In 5th Embodiment of FIG. 15, when the to-be-dried material 6 is directly pre-heated using exhaust_gas | exhaustion, ie, exhaust_gas | exhaustion, the water vapor | steam contained in exhaust_gas | exhaustion condenses, Therefore, the non-condensable gas discharge pipe 27 is joined at a junction B7 downstream of the steam trap 4 in the condensed water discharge pipe 28.
In other words, in the fifth embodiment of FIG. 15, hot water flowing through the condensed water discharge pipe 28 is mixed with water vapor and non-condensable gas flowing through the non-condensable gas discharge pipe 27, and the heat exchanger 19 is mixed. It is configured to preheat the material to be dried.

  In the operation method of the evaporator 102, when the internal pressure of the drying container 1 decreases, water vapor can be supplied directly from the water vapor boiler 7 via the low pressure side water vapor supply valve 12a. The pressure can be quickly recovered in combination with the increase in the opening degree.

  Other configurations and operational effects in the fifth embodiment in FIG. 15 are the same as those in the fourth embodiment in FIG.

Here, the supply pressure of the steam boiler 7 may be low. Therefore, exhaust heat of about 110 to 120 ° C. such as engine cooling water can be used.
In the sixth embodiment shown in FIG. 16, the steam compressor 2 is driven by the engine E, and the exhaust heat discharged from the engine E is used as a heat source for heating the steam boiler 7A.

The sixth embodiment will be described below based on FIG.
In FIG. 16, the entire evaporation apparatus is denoted by reference numeral 103.
With reference to FIG. 16, portions different from the fifth embodiment in FIG. 15 will be mainly described.

The compressor 2 is configured to be driven by the engine E.
The cooling water whose temperature has been increased by cooling the engine E is configured to circulate between the engine E and the steam boiler 7A through a line Lh with a circulation pump P interposed therebetween.
The engine E can be an internal combustion engine such as a gasoline, gas engine, or diesel engine. An external combustion engine such as a Stirling engine may be used.
If the engine cooling water is pressurized and maintained at 110 to 120 ° C., the boiler 7 can generate water vapor at around 100 ° C.

The makeup water for the steam boiler 7 needs to use soft water in order to prevent scale, and generally uses a water softener using an ion exchange resin.
In the evaporator 103 of FIG. 16, a part of the condensed water is reused as makeup water for the boiler 7 through the line 40 from the condensed water discharge port 29 using the fact that the condensed water is distilled water (soft water). I can do it.

In FIG. 16, the supply mechanism in the dry matter supply inlet (hopper) 8 is constituted by a rotary displacement type uniaxial eccentric screw pump (Mono pump) 14 a. However, you may comprise with a normal screw type feeder.
In the sixth embodiment shown in FIG. 16, the configuration and operational effects other than those described above are the same as those in the fifth embodiment shown in FIG.

Here, if the hot water temperature of the steam boiler 7 is further maintained at around 100 ° C., when the internal pressure of the drying container 1 decreases, the steam naturally evaporates in the steam boiler 7, and the steam enters the drying container 1. Since replenishment is performed, control by the water vapor supply valve 12a is not necessary.
In particular, when the steam boiler is of the electric type, the heating capacity is limited and the amount of steam generated cannot be increased, but by using the opening control of the bypass valve 21 together, the suction amount of the compressor 2 is reduced and balanced. It is possible to take advantage of the electric heat that can easily control the water temperature.
In 7th Embodiment of FIG. 17, embodiment which made the water vapor boiler an electrothermal type is shown.

Hereinafter, based on FIG. 17, the evaporation apparatus 104 of 7th Embodiment is demonstrated.
In the description of the seventh embodiment shown in FIG. 17, portions different from those of the fifth embodiment shown in FIG. 15 will be mainly described.

The steam boiler 7B is configured to be heated by the electric heater H. For example, a current is supplied to the electric heater H from a commercial power supply F through a power supply line Le.
A switch S is interposed in the power line Le, while a temperature sensor T is installed in the steam boiler 7B. The steam temperature in the steam boiler 7B is detected by the temperature sensor T, and the opening and closing of the switch S is controlled by the detected temperature.

The steam generated in the steam boiler 7B is sent directly into the drying container 1 (projecting portion 1d thereof) by the line L.
In FIG. 17, the discharge port of the main condenser 3 a is illustrated as being formed at the right end of FIG. 17, unlike FIGS. 14 to 16.

Here, since electrothermal heating has good controllability, it is easy to keep the water temperature of the boiler 7B constant. Therefore, for example, if the water temperature is kept at 100 ° C., water vapor with an absolute pressure of 101 kPa can be obtained. Therefore, as in the second embodiment of FIGS. 7 and 8, members corresponding to the water vapor supply valves 12a and 12b need not be provided. Can supply water vapor close to atmospheric pressure.
Incidentally, if the water temperature is kept at 95 ° C., the suction side of the water vapor compressor 2 becomes the atmospheric pressure or lower, so it is possible to generate water vapor with an absolute pressure of 84 kPa.

  When the power receiving capacity is limited, since the heat output such as gas burning or kerosene burning cannot be obtained from the electric heater H, the amount of water vapor generated is small. Therefore, the suction side of the compressor 2 may be in a vacuum. This can be dealt with by increasing the opening of the flow rate adjusting valve 21 (bypass valve) of the bypass line Lc and decreasing the suction amount of the compressor 2.

  The other configurations and operational effects of the seventh embodiment of FIG. 17 are the same as those of the fifth embodiment of FIG.

Next, another type of condenser different from the condenser shown in FIGS. 10 to 13 will be described with reference to FIGS. The condenser shown in FIGS. 10 to 13 is formed in a helical coil shape, whereas the condenser shown in FIGS. 18 to 20 includes a plurality of tubes 31a extending in the longitudinal direction of the condenser. 32a is arranged radially outward and at equal intervals in the circumferential direction, and has a bowl shape.
When the overall shape of the condenser shown in FIGS. 18 to 20 is further outlined, it looks like a rotating device for movement of rodents (for example, squirrels and rats) bred as pet animals (so-called “squirrel rod”). It is configured.

18 and 19, the condenser 3 includes a hollow cylindrical body 32a, a plurality of hollow tubes 31a, and a spoke-shaped support material (hollow spoke) 33 that supports the tubes 31a on the body 32a. have.
As shown in FIG. 18, two condensers 3 are provided in the drying container 1 to constitute a main condenser 3 a.

In FIG. 18, the code | symbol 3b has shown the subcondenser.
The sub-condenser 3b can be configured not only as illustrated in FIG. 18 but also so as to cover the periphery of the drying container 1.

As clearly shown in FIG. 18, the plurality of hollow tubes 31a are arranged radially outward of the trunk portion 32a, and are arranged at equal intervals in the circumferential direction of the trunk portion 32a. And the tube 31a is extended in parallel with the trunk | drum 32a so that it may show clearly in FIG. In other words, the tube 31a and the trunk portion 32a extend in the longitudinal direction of the condenser.
In FIG. 18, the support member 33 extends outward in the radial direction, and a plurality of support members 33 are provided to support one tube 31a. Note that only two support members 33 are shown in FIG.

A scraper 35 is provided at the radially outer end of the tube 31a. The scraper 35 has an effect of scraping and removing the object to be dried fixed around the other condenser 3.
As clearly shown in FIG. 18, the two condensers 3 are arranged by adjusting the relative positions of the plurality of tubes 31a so as not to interfere with each other during rotation.

In FIG. 19, the body portion 32 a is configured integrally with left and right end surfaces 32 e and rotation shafts 32 SR and 32 SL at an end portion in the axial direction (left and right direction in FIG. 19).
The rotation of the rotation shafts 32SR and 32SL is transmitted from the electric motor 13 via a rotation transmission system (not shown in FIG. 19).
In FIG. 19, the left side in the figure is the side of the insertion port 8 or the feeders 14 and 14a (see FIGS. 14 to 17).

In the rotating shaft 32SR on the right side of FIG. 19, holes 32h through which water vapor in the drying container 1 flows are formed at equal intervals in the circumferential direction. The hole 32h communicates with the blind hole 32eh extending in the axial direction in the end surface 32e, and the blind hole 32eh communicates with the internal space 32i of the trunk portion 32a.
Here, a plurality of holes 32er extending radially outward branch from the blind hole 32eh, and the holes 32er communicate with the internal space 31ai of the tube 31a.
As clearly shown in FIG. 18, the holes 32er are formed at equal intervals in the circumferential direction.

In FIG. 19 again, a plurality of holes 32er and blind holes 32eh extending radially outward are also formed on the left end surface 32e in FIG.
The blind hole 32eh communicates with the hollow portion 32i of the trunk portion 32a. At the same time, a plurality of holes 32er extending outward in the radial direction communicate with the blind hole 32eh.

Further, in the hollow portion 32i of the trunk portion 32a, a hole 32ih that is in communication with a plurality of holes 32er extending radially outward is formed at the left end portion in FIG. 19 and radially outward. .
As clearly shown in FIG. 18, the hole 32ih and the hole 32er have the same circumferential position.

A condensate drain hole 32dh extending outward in the radial direction is formed at the left end portion of the blind hole 32eh formed in the left end surface 32e of FIG.
The condensed water drain hole 32dh is formed to discharge condensed water from the condenser 3, and condensed water flows through the condensed water drain hole 32dh.

In the blind hole 32eh on the left side of FIG. 19, a partition member 32w is disposed in the vicinity of the boundary with the hollow portion 32i.
As shown in FIG. 20, the partition member 32w is configured by bundling a plurality (six) of partition-like members in the vicinity of the central axis of the blind hole 32eh, and the blind hole 32eh is divided into a plurality of spaces (6 in FIG. 20). It is divided into compartments.
In addition, in FIG. 19, the code | symbol 34 has shown the reinforcing material for attaching the tube 31a to the trunk | drum 32a.

With reference to FIG. 19, the flow of water vapor or condensed water in the condenser 3 shown in FIGS.
In the condenser 3, since water vapor | steam produces | generates condensation heat and condenses, the internal space 32i of the trunk | drum 32a and the internal space 31ai of the tube 31a are low pressure rather than the compressor discharge steam piping 11. FIG. Therefore, as indicated by an arrow V in FIG. 19, the water vapor flows into the condenser 3 through the hole 32 h formed in the end surface 32 e on the right side in FIG. 19.

The inflowed water vapor flows through the blind hole 32eh, partly flows through the space 31ai in the tube 31a via the hole 32er, and partly flows into the internal space 32i of the trunk part 32a.
When flowing through the space 31ai in the tube 31a or when flowing into the internal space 32i of the trunk portion 32a, the water vapor generates heat of condensation. The heat of condensation is transferred to the object to be dried near the condenser 3 and heated. Thereby, the water | moisture content contained in the to-be-dried material of the trunk | drum 32a and the tube 31a vaporizes, water vapor | steam generate | occur | produces from a to-be-dried material, and to-be-dried material dries.

When the heat of condensation is generated and the water vapor becomes water (condensed water), the condensed water accumulated in the tube 31a located above in the condenser 3 extends in the radial direction as indicated by an arrow Vu. It falls in the hole 32er.
The condensed water falling in the hole 32er flows to the left side of FIG. 19 along the partition wall of the partition member 32w, and is discharged from the condenser 3 as indicated by an arrow D through the condensed water discharge hole 32dh.

On the other hand, the condensed water accumulated in the internal space 31ai of the tube 31a located below the condenser 3 extends in the radial direction when the tube 31a reaches the upper position due to the rotation of the condenser 3. Falls in the hole 32er.
The condensed water accumulated in the internal space 32ai of the trunk portion 32a flows into the internal space 31ai of the tube 31a located below the condenser 3 via the holes 32ih and 32er. And when the said tube 31a comes to an upper position with the condensed water collected in the tube 31a, it will fall in the hole 32er extended to radial direction.

FIG. 21 shows an eighth embodiment of the present invention, which uses the condenser shown in FIGS.
In FIG. 21, the steam boiler 7 </ b> B generates water vapor by heating water with an electric heater H connected to a commercial power source F. Heating by the electric heater H is adjusted by the water temperature in the boiler 7B detected by the boiler water temperature sensor T.
A replenishment water line 40 of the boiler 7B branches off from the condensed water pipe 28 in which the steam trap 4 is interposed, and a part of the condensed water is supplied to the boiler 7B through the line 40.

The drying container 1 is provided with a check valve 15a and an opening / closing valve 15b, and the internal pressure of the drying container 1 does not increase to atmospheric pressure or higher, and does not decrease to a degree of vacuum that the drying container 1 is crushed. It is adjusted like this.
When the interior of the drying container 1 reaches atmospheric pressure or higher, the check valve 15a is opened. On the other hand, if the pressure in the drying container 1 becomes lower than a predetermined value (if the negative pressure is too strong), the drying container 1 itself may be crushed. Incorporate into.
Note that the supply mechanism in the dry matter supply inlet (hopper) 8 is constituted by a rotary displacement type uniaxial eccentric screw pump (Mono pump) 14a.

In FIG. 21, a water vapor line LP9 having a purge valve P is communicated with the discharge valve 9 from the sub-condenser 3b. The configuration and operational effects will be described later with reference to FIGS.
Other configurations and operational effects of the eighth embodiment shown in FIG. 21 are the same as those of the embodiments of FIGS.

Next, the structure of the discharge valve communicating with the water vapor line LP9 will be described with reference to FIGS.
The discharge valve 9 shown in FIG. 22 is composed of a rotary valve RV.
Here, when the rotary object RV is rotated in the direction of the arrow CCW in discharging the dry matter that has been dried, the dry matter falls to the lower side of FIG. There is a possibility that air, which is a non-condensable gas, flows into the drying container 1.

On the other hand, in FIG. 22, as described above with reference to FIG. 21, the steam is filled into the rotary valve RV as shown by the arrow HG through the steam line LP9 communicating with the sub-condenser 3B. .
Therefore, even after the object to be dried falls down, the space of the rotary valve RV is filled with water vapor, so that air does not flow into the space α.
As shown in FIG. 21, the water vapor line LP9 communicates with the sub-condenser 3b in the upper region where only water vapor exists and no condensed water exists. For this reason, water vapor flows through the line LP9.

FIG. 23 shows another aspect of the discharge valve 9 used in the illustrated embodiment.
The discharge valve 9 shown in FIG. 23 is provided with an actuator A1 and a valve body Vb1 inside a casing 9c through which a water vapor line LP9 communicates, and an actuator A2 and a valve body Vb2 outside the casing 9c. Yes. The valve bodies Vb1 and Vb2 are configured to be operated in the vertical direction in FIG. 23 by actuators A1 and A2, respectively.

The valve body Vb1 closes the input side pipe 9i of the discharge valve 9 when moving upward, and opens the input side pipe 9i of the discharge valve 9 when moving downward. The valve body Vb2 closes the discharge side pipe 9o of the discharge valve 9 when moving upward, and opens the discharge side pipe 9o of the discharge valve 9 when moving downward.
Here, the actuators A1 and A2 are configured such that when one of the valve bodies Vb1 and Vb2 moves downward to open the pipe, the other always moves upward to close the pipe. . In other words, the actuators A1 and A2 connect the valve bodies Vb1 and Vb2 so that the valve body Vb1 does not open the input side pipe 9i and the valve body Vb2 opens the discharge side pipe 9o. It is operating.

In the embodiment of FIG. 23, water vapor is supplied to the inside of the casing 9c via the water vapor line LP9 as in FIG. Therefore, when the valve body Vb1 opens the input side pipe 9i, it is water vapor that flows backward through the input side pipe 9i, and when the valve body Vb2 opens the discharge side pipe 9o, the casing Since water vapor is filled inside 9c, it is difficult for air to flow into casing 9c.
At the same time, the valve body Vb1 closes the input side pipe 9i or the valve body Vb2 closes the discharge side pipe 9o, so that outside air (air which is non-condensable gas) is discharged from the discharge side pipe 9o and The possibility of flowing into the drying container 1 via the input side pipe 9i is extremely reduced.

Next, a ninth embodiment will be described with reference to FIG.
The ninth embodiment of FIG. 24 uses the condenser shown in FIGS. 18 to 20 as in the eighth embodiment of FIG. However, in the embodiment of FIG. 21, the drying container 1 is disposed in an inclined manner, whereas in the ninth embodiment of FIG. 24, the drying container 1 is disposed substantially horizontally.
In FIG. 24, an object to be dried indicated by an arrow 6 is sucked by a hose or the like interposed with a slurry pump 14c. The sucked object to be dried is preheated by recovering heat from the condensed water (hot water) in the double-pipe heat exchanger 19a, and is put into the drying container 1 from the left end.

The main water vapor condenser 3a is configured as shown in FIGS. 18 to 20 and has a so-called “squirrel cage shape”. By rotating the so-called “squirrel cage” main water vapor condenser 3 a, the material to be dried can be uniformly dispersed inside the drying container 1.
As the object to be dried moves inside the drying container 1 to the right side in FIG. 24, the heat of condensation of water vapor is input from the main water vapor condenser 3a and heated, so that the moisture is reduced and dried.
The object to be dried (dried substance) after drying is discharged from the right end of the drying container 1.

In the embodiment of FIG. 24, the dry matter discharge valve 9a is configured as a rotary drum (rotary bucket) type, and before discharging the dry matter out of the system, the water vapor from the sub-condenser 3b is supplied to the line LP9 and the water vapor. It is supplied via the supply valve 30. Such water vapor supply can reduce the amount of air (non-condensable gas) entering the rotary drum of the discharge valve 9a as described above with reference to FIG.
The water vapor supply valve 30 may be a purge valve as in FIG.

As the rotating drum itself, a known one that is commercialized as “ball feeder” or “drum feeder” can be applied. And you may use the same structure for the inlet (left end part of FIG. 24) of to-be-dried material.
Similarly, a rotary valve and a double damper can also be used as a valve mechanism at the inlet (left end portion in FIG. 24) of the object to be dried.

  In FIG. 24, the drying container 1 includes a check valve 15a so that the internal pressure does not exceed atmospheric pressure. That is, when the internal pressure of the drying container 1 becomes higher than the atmospheric pressure, the check valve 15a is opened to the atmosphere side to release the pressure in the drying container 1 out of the system.

An exhaust valve 25 is provided in the condensate water pipe 28 that communicates the sub-condenser 3b with the steam trap 4. At the start of operation of the evaporator according to FIG. 24, the air remaining in the main condenser 3a and the sub condenser 3b can be discharged by opening the exhaust valve 25.
24, at the end of the operation of the evaporator according to FIG. 24, the exhaust valve 25 is opened, the outside air introduction valve 24 is also opened, and the air sucked from the outside air introduction valve 24 is discharged from the exhaust valve 25, thereby compressing. While drying the inside of the machine 2, the inside of the main condenser 3a and the sub-condenser 3b can also be dried.

Although not shown, the same mechanism as the steam supply mechanism as shown by the line LP9 and the steam supply valve 30 in FIG. 24 may be configured in the screw feeder 14 or the suction port 14a.
Other configurations and operational effects in the ninth embodiment in FIG. 24 are the same as those in the eighth embodiment in FIG.

  It should be noted that the illustrated embodiment is merely an example, and does not limit the technical scope of the present invention.

1 is a block diagram showing a first embodiment of the present invention. The block diagram which shows the modification of 1st Embodiment. The flowchart which shows a part of control in 1st Embodiment. The flowchart which shows a different part from FIG. 3 of the control in 1st Embodiment. The flowchart explaining the opening degree control of the bypass valve in 1st Embodiment. The block diagram which shows another modification in 1st Embodiment. The block diagram which shows 2nd Embodiment. The flowchart which shows the control of 2nd Embodiment. The block diagram which shows 3rd Embodiment. The top view explaining schematic structure of the condenser used by this invention. The longitudinal cross-sectional view explaining the structure of the condenser used by this invention. The cross-sectional view explaining the structure of the condenser used by this invention. FIG. 13 is a transverse sectional view showing a modification of the condenser in FIG. 12. The block diagram which showed the structure of the whole apparatus of 4th Embodiment. The block diagram which showed the structure of the whole apparatus of 5th Embodiment. The block diagram which showed the structure of the whole apparatus of 6th Embodiment. The block diagram which showed the structure of the whole apparatus of 7th Embodiment. The cross-sectional view explaining the structure of another condenser used by this invention. The longitudinal cross-sectional view which partially fractures and shows the condenser shown in FIG. Aa 'arrow expanded sectional view of FIG. The block diagram which showed the structure of the whole apparatus of 8th Embodiment. Explanatory drawing which shows the structure of the discharge valve in embodiment of illustration. Explanatory drawing which shows the discharge valve of the aspect different from FIG. The block diagram which showed the structure of the whole apparatus of 9th Embodiment. Explanatory drawing of a prior art (nonpatent literature 1). The block diagram of the apparatus regarding patent document 1 by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Drying container 2 ... Steam compressor / compressor 3 ... Steam condenser 3a ... Main condenser 3b ... Subcondenser 4 ... Steam trap 5 ... Steam venting Valve 6 ... Dried object 7 ... Steam boiler 8 ... Dried object inlet / hopper 9 ... Dry substance outlet 10 ... Compressor intake steam pipe / intake pipe 11 ... Compressor discharge steam pipe / discharge pipe 12a ... low pressure side steam supply valve / steam supply valve 12b ... high pressure side steam supply valve / steam supply valve 21 ... bypass flow control valves 22, 23 ... pressure Sensor 24 ... Outside air introduction valve

Claims (14)

  In an evaporator having a drying container, a steam compressor, a steam condenser in heat exchange relationship with the contents of the drying container, and a steam line communicating with these devices, the discharge side of the steam compressor and steam condensation A bypass line having a flow rate adjusting valve is branched from a steam line communicating with the steam generator, and the bypass line is joined to a steam line communicating with the drying container and the suction side of the steam compressor. An evaporator having a pressure detection means for detecting the internal pressure and configured to control the flow rate adjustment valve so that the pressure in the drying container does not drop below a set value.   In an evaporator having a drying container, a steam compressor, a steam condenser in heat exchange relationship with the contents of the drying container, and a steam line communicating with these devices, the discharge side of the steam compressor and steam condensation A bypass line with a flow control valve is branched from a steam line that communicates with the vessel, and the bypass line merges with a steam line that communicates the drying vessel and the suction side of the steam compressor. Evaporation characterized in that pressure detection means for detecting the pressure of the discharge pipe of the compressor is provided, and the flow control valve is controlled so that the pressure of the discharge pipe of the steam compressor does not become higher than the set value. apparatus.   In an evaporator having a drying container, a steam compressor, a steam condenser in heat exchange relationship with the contents of the drying container, and a steam line communicating with these devices, the steam condenser is rotated a plurality of times. The rotors are arranged in parallel, and the rotor is made of a steel pipe, and the rotors are arranged so as to rotate in parallel so that the rotors do not interfere with each other. Evaporating device.   The evaporator according to claim 3, wherein the rotor is formed in a coiled coil shape of a steel pipe.   The rotor is composed of a plurality of straight steel pipes, and each of the straight steel pipes is arranged in parallel with the rotation axis, and is radially outward of the rotation axis and equally spaced in the circumferential direction. The evaporator according to claim 3, wherein each of the straight steel pipes is communicated with a passage provided in the rotating shaft by a hollow support material.   The evaporator according to any one of claims 1 to 5, wherein the steam condenser is configured by arranging a plurality of stages in series, and is provided with a non-condensable gas discharge valve communicating with the last stage steam condenser. .   The evaporator according to any one of claims 1 to 6, wherein the gas flowing through the non-condensable gas discharge line is preheated by being brought into direct contact with an object to be dried.   A heat exchanger is provided in the mechanism for feeding the material to be dried, a gas flowing through the noncondensable gas discharge line is introduced into the heat exchanger, and a part of the enthalpy of the gas is covered through the heat exchanger. The evaporator according to any one of claims 1 to 7, wherein the evaporator is configured to be put into a dried product.   The steam generation means is configured to be heated by an electric heater, and is configured to maintain the temperature of the hot water in the steam generation means at a temperature near the boiling point at atmospheric pressure. Evaporation equipment.   The evaporation container according to any one of claims 1 to 9, wherein the drying container is provided to be inclined with respect to a horizontal plane, and the mechanism for feeding the material to be dried is located below the mechanism for discharging the material to be dried. apparatus.   11. The steam pipe according to claim 1, further comprising: a steam pipe that communicates between any position from the steam compressor to the outlet of the steam condenser and the inside of a gate valve provided in the discharge system and the suction system of the drying container. Any one of the evaporators.   2. The method for controlling an evaporator according to claim 1, wherein the step of detecting the pressure in the drying container by the pressure detecting means, the step of comparing the detected pressure in the drying container with a set value, and the pressure in the drying container are set. And a step of increasing the opening of the flow regulating valve when the pressure is lower than the value.   3. The method for controlling an evaporator according to claim 2, wherein the step of detecting the pressure of the discharge pipe of the steam compressor by the pressure detecting means, the step of comparing the pressure of the discharge pipe of the steam compressor and the set value, and the steam compressor And a step of increasing the opening of the flow regulating valve when the pressure of the discharge pipe is higher than a set value.   The method for controlling an evaporator according to any one of claims 1 and 2, further comprising the step of opening the flow rate adjustment valve of the bypass line at the start of operation to raise the temperature of the interior of the steam compressor.

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