JP2016034455A - Energy recovery method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively use thermal energy of surplus steam, and reduce energy used for rice cooking in a continuous type rice cooking device that uses superheated steam.SOLUTION: A continuous type rice cooking device includes a chamber 3 equipped with a conveyor 2 for conveying rice, a superheated steam supply device (not illustrated) for supplying superheated steam to the inside of the chamber 3, a heat exchanger 10 for producing hot water by heat exchange with steam discharged from the chamber 3, and a water spray nozzle 5 for spraying the hot water produced by the heat exchanger 10 in the chamber 3. Rice is cooked by the continuous supply of the superheated steam and the hot water to the inside of the chamber 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an energy recovery method, and more particularly to a method of recovering energy contained in discharged water vapor.

  For example, Patent Literature 1 and Patent Literature 2 disclose continuous rice cookers. These rice cookers include a chamber to which superheated steam is supplied, a conveyor that conveys rice, and a watering device that sprinkles the rice conveyed in the chamber. The rice conveyed by the conveyor is cooked with the superheated steam supplied to the chamber and the hot water supplied from the sprinkler, and is carried out from the chamber as cooked rice.

  Superheated steam is obtained by heating saturated steam under pressure and has large heat energy, so that rice can be heated in a short time.

  However, the thermal energy used for heating the rice is only a part of the thermal energy of the superheated steam supplied into the chamber, and most of the energy is released outside the chamber as high-temperature steam.

  On the other hand, for example, Patent Document 3 and Patent Document 4 describe a method of reusing water vapor after heating or drying using heat energy of superheated water vapor. In the former, the coffee beans are roasted by bringing the coffee beans into contact with the superheated steam, and after the roasted coffee beans are separated, the steam is heated again and used again as superheated steam for roasting. Moreover, in the latter, after drying a foodstuff by spraying a water-containing foodstuff in superheated steam, the steam utilized for drying is overheated and utilized again as superheated steam.

JP 2001-169915 A International Publication WO2013 / 164919 Japanese Patent Laid-Open No. 10-57247 JP-T 09-501098

  This invention is made | formed in view of said background art, Comprising: It collects the thermal energy which the discharged | emitted water vapor | steam has, and makes it a subject to reduce energy loss, for example in a continuous-type rice cooker.

  The energy recovery method according to the present invention is a method for recovering thermal energy of water vapor discharged from a chamber, wherein the water is heated by heat exchange with water vapor discharged from the chamber.

  According to the method of the present invention, a part of the thermal energy supplied as saturated steam or superheated steam is recovered as thermal energy for hot water production, and the hot water produced thereafter can be used for various applications, so energy loss. For example, energy saving in the continuous rice cooking method is achieved.

FIG. 1 is a schematic configuration diagram of a rice cooker which is an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of a rice cooker which is another embodiment of the present invention.

  The method for recovering energy of wastewater steam according to the present invention is characterized in that heat exchange is performed with water vapor discharged from a chamber, and water is heated to recover a part of thermal energy of the wastewater steam. In other words, the present invention is a method of recovering, as heat water, heat energy of water vapor that is not used for heating but is discharged outside the chamber from among water vapor that is supplied for heating into the chamber. The method can be carried out in a recovery apparatus including a chamber to which water vapor is supplied and a heat exchanger that exchanges heat between water vapor (drain steam) discharged from the chamber and water.

  In the present invention, the chamber means a housing having a structure capable of heating an object by bringing it into contact with the object (heating object) with water vapor. The chamber has a supply port to which water vapor is supplied and an exhaust port from which water vapor is discharged, and the chamber is almost filled with the supplied water vapor. The method of bringing into contact with the object is a method in which water vapor is brought into direct contact with the object to be heated, and can be a method in which water vapor is brought into contact with the object to be heated indirectly. Examples of the former method include a method of supplying water vapor into a chamber in which an object is placed. Examples of the latter method include a method in which a chamber supplied with water vapor is brought into contact with a heated object outside the chamber, for example, a method in which a heated object is brought into contact through the upper wall of the chamber. Water vapor is continuously supplied into the chamber and drain steam is continuously exhausted from the chamber.

  In the present invention, the steam supplied into the chamber may be either saturated steam or superheated steam, preferably superheated steam. Superheated steam means steam obtained by superheating saturated steam, and can be produced by any method of heating while maintaining normal pressure or heating while applying pressure. This is because superheated steam has a large thermal energy (latent heat), which is advantageous for heating an object to be heated, but the steam discharged from the chamber also has a large heat energy, and the discarded heat energy is large. The temperature of superheated steam exceeds 100 ° C. at normal pressure, and the upper limit thereof is not particularly limited. For example, it is 500 ° C. or lower, 300 ° C. or lower, 200 ° C., or 180 ° C.

  In the present invention, the drainage steam means water vapor after being used for heating the object to be heated, and is discharged from the exhaust port of the chamber. The discharged steam can include superheated steam.

  Waste water vapor discharged from the chamber is supplied to the heat exchanger. The heat exchanger is used in the meaning that is commonly used by those skilled in the art, and uses the heat energy of the wastewater vapor for heating the refrigerant. The structure of the heat exchanger is not limited as long as the heat exchanger can exchange heat between the waste water vapor and the refrigerant and can take out the warmed refrigerant to the outside. In the present invention, the refrigerant is preferably water.

  The hot water obtained by the present invention is used for various applications. The application is, for example, reuse as steam supplied to the chamber, in particular as water for producing superheated steam, and as hot water for hydration or sprinkling into the chamber. In particular, when the temperature of the superheated steam exceeds 180 ° C. to 200 ° C., drying of the heated object that is in direct contact tends to proceed excessively. Therefore, drying or heating of the object to be heated is prevented by adding water or watering the chamber. Moreover, a heating target object can be so-called steamed like the rice cooking method mentioned later with it. There is no particular limitation on the method of water addition or watering into the chamber, and for example, watering using a watering device provided with a watering nozzle is exemplified.

  The object to be heated is not particularly limited, and may be one that is heated (including steamed) and used as food, one that is heat sterilized, or one that is dried and used. It does not matter whether the object to be heated is a food or drink. Examples of foods and drinks include various beverages such as drinking water and milk, vegetables (fruit vegetables such as pumpkins, root vegetables such as strawberries, leaf vegetables such as spinach, fungi such as enoki mushrooms), rice, and meat. . Moreover, water, oil, wood, a plant, etc. are illustrated other than food / beverage products.

  Heating with water vapor is a so-called batch method, that is, a method of continuously supplying water vapor with an object to be heated in the chamber, or a continuous method, that is, heating using a conveyer or the like in the chamber. Any of the methods of continuously supplying water vapor while continuously supplying the object may be used. In particular, by continuously supplying heating objects (processing objects) such as vegetables and rice, steamed processed foods and dried processed foods can be provided efficiently and with less energy.

  The energy recovery method of the present invention can be used, for example, in a continuous rice cooking method in which superheated steam and hot water are supplied to cook rice. In other words, the rice cooking method according to the present invention is a continuous rice cooking method in which superheated steam and hot water are supplied into the chamber to obtain hot water by heat exchange with the steam discharged from the chamber, and the hot water is cooked. It is a method of using it as a part or all of the hot water required. The method includes a chamber having a transfer device for transferring rice, a superheated steam supply device for supplying superheated steam into the chamber, and a heat exchanger for producing hot water by heat exchange with the steam discharged from the chamber. And the rice cooker provided with the water sprinkling apparatus which sprinkles the warm water manufactured by the said heat exchanger to the rice in the said chamber may be implemented. The chamber has a carry-in port for carrying rice into the chamber, a carry-out port for carrying out cooked cooked rice, and an exhaust port for supplying water vapor to the heat exchanger, and the exhaust port is provided with piping to the heat exchanger .

  The continuous rice cooking method and rice cooking apparatus for cooking rice by supplying superheated steam and warm water into the chamber are known methods as described above, and are, for example, the methods and rice cooking apparatuses described in Patent Literature 1 and Patent Literature 2. Is exemplified.

  Superheated steam is continuously supplied into the chamber, and the thermal energy (latent heat) of the superheated steam is used for cooking rice. The water vapor after the latent heat is removed is exhausted from the chamber. The discharged water vapor is supplied to a heat exchanger provided outside the chamber through a pipe. The water vapor can include superheated water vapor. The heat exchanger performs heat exchange between the supplied water vapor and the supplied water, and converts the supplied water into warm water. The structure of the heat exchanger is not limited as long as heat exchange can be performed between water vapor and water. The heat exchanger can be, for example, a condenser. It can also be a heat exchanger with a forced ventilation mechanism. In particular, the latter heat exchanger is preferable because it has an advantage that the temperature of the hot water can be adjusted by adjusting the ventilation rate. The heat exchanger is, for example, a counter-flow heat exchanger, and may be a co-current heat exchanger.

  Part or all of the hot water obtained by heat exchange is sprinkled from the sprinkler to the rice in the chamber. At this time, when the temperature of the hot water obtained by heat exchange is lower than the temperature required for rice cooking, it can be heated by a newly added heating device. Moreover, when the amount of warm water obtained by heat exchange is less than the required amount, warm water produced by a newly added warm water production apparatus may be added. On the other hand, when the temperature of the warm water is high, the temperature of the warm water can be lowered by adjusting the ventilation rate. In this way, the heat energy of the water vapor after the latent heat that had been discarded so far is used for the production of hot water used for watering, resulting in the production of cooked rice with less energy consumption than conventional rice cooking methods. Can be done.

  Next, the present invention will be described more specifically with reference to the accompanying drawings. In addition, although the case where it uses as a continuous-type rice cooker using rice is described in each following Example, it cannot be overemphasized that this invention is not limited to the following Example.

  A rice cooker 1 shown in FIG. 1 is a rice cooker 1 provided with a heat exchanger having a so-called ventilation function. The rice cooker 1 includes a chamber 3 having a conveyor 2 that is a conveying device for continuously conveying rice, a superheated steam supply device (not shown) that supplies superheated steam into the chamber 3, and the chamber 3. A heat exchanger 10 for producing hot water by heat exchange with the discharged steam, a watering nozzle 5 for watering the hot water produced by the heat exchanger 10 to the rice in the chamber 3, and the rice to the conveyor 2 A supply device 6 is provided. The chamber 3 includes a carry-in port 3a for carrying rice to be cooked (raw rice) into the chamber 3, a carry-out port 3b for carrying out cooked rice in the chamber 3, and water vapor in the chamber 3 from the heat exchanger 10 And an exhaust port 3c for supplying to the chamber 3, and the inside of the chamber 3 is almost at normal pressure.

  The heat exchanger 10 includes a cooling pipe 12 through which water serving as a refrigerant flows, a cooling tower 11 that forms a space in which the cooling pipe 12 and water vapor are brought into contact, and an exhaust fan 13. The cooling tower 11 has an opening 14 at the top of the tower, and a ventilation pipe 15 is provided through the opening 14. The ventilation pipe 15 becomes an air exhaust path after being cooled, and the lower end of the ventilation pipe 15 is located below the inside of the cooling tower 11. The cooling pipe 12 is spirally arranged around the ventilation pipe 15, and one end (upper end in the figure) of the cooling pipe 12 is a water amount adjuster (not shown) and a temperature adjuster (if necessary) ( It is connected to the watering nozzle 5 via a not shown). The other end (lower end portion in the figure) of the cooling pipe 12 is connected to a water supply device (not shown), and water suitable for drinking (for example, clean water) is supplied from the water supply device. An exhaust pipe 8 connected to the exhaust port 3 c of the chamber 3 is connected to the lower part of the cooling tower 11, and water vapor discharged from the chamber 3 is supplied to the cooling tower 11. The lower end of the cooling tower 11 is provided with a drain port 16 for draining condensed water generated inside the tower. The exhaust fan 13 is installed above the opening of the ventilation pipe 14, promotes the discharge of the dehumidified air, and adjusts the discharge amount.

  Raw material rice is continuously dropped from the supply device 6 onto the conveyor 2, and the dropped raw material rice is conveyed into the chamber 3. In the chamber 3, superheated steam is supplied from below the conveyor 2, and hot water is sprinkled from above the raw rice, whereby the raw rice is cooked. At this time, the rice on the conveyor 2 is agitated by the agitating device 7, and the rice cooking is made uniform. Also, waste water in the chamber 3 (water generated from excess hot water or superheated steam) is discharged from the waste water pipe and discarded.

  Part of the thermal energy of the supplied superheated steam is used to heat the raw rice, and the steam thereafter is discharged from the chamber 3 to the heat exchanger 10 through the exhaust pipe 8. In the heat exchanger 10, heat exchange is performed between the supplied water vapor and the water passed through the cooling pipe 12, and the water is heated. The heated water is used as hot water for watering. As described above, at least a part of the thermal energy not used in the chamber 3 is used for the production of hot water, and energy loss is reduced.

  The rice cooker 1 shown in FIG. 2 has substantially the same configuration as the rice cooker shown in FIG. 1, and the rice cooker shown in FIG. 2 includes a heat exchanger 20 that is a so-called concentrator that does not have a ventilation function. This is different from the rice cooker 1 shown in FIG. The heat exchanger 20 has a cooling tower 21 having a drain port 16 at the lower end. The cooling tower 21 does not include the exhaust ventilation pipe 15 shown in FIG. 1, and the air after the moisture and water vapor generated in the cooling tower 21 are cooled is discharged to the outside from the drain port 16. The heat exchanger 20 which is such a concentrator can also be used.

2 Conveyor 3 Chamber 5 Watering nozzle 8 Exhaust pipe 10 Heat exchanger 11 Cooling tower 12 Cooling pipe 13 Exhaust fan

Claims (11)

A wastewater steam energy recovery method for recovering thermal energy of water vapor discharged from a chamber,
A recovery method, wherein water is heated by heat exchange with water vapor discharged from the chamber.   The recovery method according to claim 1, wherein the steam is steam discharged from a chamber supplied with superheated steam.   The recovery method according to claim 1, wherein the heated water is used as at least a part of the water source of the superheated steam.   The recovery method according to claim 1 or 2, wherein the warmed water is sprinkled into the chamber. A chamber supplied with water vapor;
An energy recovery device for wastewater steam, comprising a heat exchanger for exchanging heat between water vapor discharged from the chamber and water.   6. The energy recovery apparatus according to claim 5, wherein the water vapor supplied to the chamber is superheated water vapor.   The energy recovery device according to claim 5, further comprising a supply device that supplies hot water obtained by the heat exchanger into the chamber.   The energy recovery apparatus according to any one of claims 5 to 7, further comprising a transfer device that continuously supplies an object to be heated into the chamber.   The energy recovery device according to claim 8, further comprising a watering device that sprays the hot water onto the heating object. In the continuous rice cooking method of supplying rice with superheated steam and warm water into the chamber where rice is continuously conveyed,
A continuous rice cooking method, wherein water heated by heat exchange with water vapor discharged from the chamber is used as part or all of the hot water. A chamber with a transfer device for transferring rice;
A superheated steam supply device for supplying superheated steam into the chamber;
A heat exchanger for producing hot water by heat exchange with water vapor discharged from the chamber;
A continuous rice cooking apparatus comprising water sprinkling means for sprinkling hot water produced by the heat exchanger to rice in the chamber.

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