JP2014098371A - Heat circulation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat circulation system capable of effectively reducing a loss of exergy by efficiently compressing gas having a relatively small flow rate.SOLUTION: After a supplied substance is heat-treated and gas is generated through a predetermined process (distilling or drying) using the heated substance, a temperature of the gas is increased by compressing the gas with a compressor 10 and heat due to the temperature increase is used as a heat source of a heating process of the substance. Thus, a heat circulation system can reduce energy consumption by increasing the temperature of the gas having a low exergy rate by compressing the same and utilizing the heat due to the temperature increase as the heat source of the heating process. By using a Roots dry pump as the compressor 10 which performs adiabatic compression to increase the temperature of the gas, the heat circulation system can efficiently compress the gas with reduced power consumption compared to a centrifugal rotary type or a screw type compressor even when a flow rate of the gas is small.

Description

  The present invention relates to a thermal circulation system that reduces the loss of exergy by reusing heat generated by gas compression in a heating process.

  Exergy is energy that can be theoretically extracted as an effective work from a certain system, and the ratio of exergy to the total energy is called exergy rate. The exergy rate varies depending on the form of energy, while electric energy is relatively high at 100% and fossil energy at 90%, whereas thermal energy is as low as about 10% at 100 ° C and about 50% at 1000 ° C. Therefore, in a conventional general system (steam turbine, etc.) that generates power by the heat generated by burning fossil fuel, exergy that is discarded without being used is large, and the utilization efficiency of energy resources is low. Problems have been pointed out.

  Non-Patent Document 1 below proposes a thermal circulation system that is devised so that the loss of exergy is further reduced by reviewing the use of energy from the viewpoint of exergy. This thermal circulation system raises the temperature by applying adiabatic compression work to the gas carrying thermal energy with a small exergy rate, and reuses that heat in the heating process. It can be applied to various fields such as synthesis. By incorporating a heat circulation system into the process, exergy loss can be suppressed compared to conventional methods in which heat is applied from the outside, so that energy consumption can be greatly reduced.

Junji Tsutsumi, "Innovative Energy Technology for Building a Low Carbon Society", [online], May 10, 2010, University of Tokyo, [November 14, 2012 search], Internet <URL: http: / /www.energy.iis.u-tokyo.ac.jp/tsutsumi/20100510.pdf>

  In order to realize the above-described heat circulation system, a compressor for adiabatically compressing gas to generate heat is essential. For example, a compressor used in a heat circulation system of water vapor is required to operate at a temperature of at least a few tens of degrees Celsius or higher and to compress to a pressure higher than atmospheric pressure. There are examples of using a centrifugal rotation type or screw type compressor for compressing water vapor, but since the power consumption is large, there are many applications for a large flow rate, which is not suitable for applications with a relatively small flow rate.

  This invention is made | formed in view of this situation, The objective is to provide the thermal circulation system which can compress a gas with comparatively small flow volume efficiently, and can reduce an exergy loss effectively.

  The thermal circulation system according to the first aspect of the present invention includes a compression unit that compresses a gas, and heat that is generated along with the compression of the gas by the compression unit to the gas that is sent to the compression unit or the compression unit. And a heat exchanging part that transfers to the material used to generate the gas to be fed. The compression unit includes a roots-type dry pump including a rotor chamber that houses a pair of rotors that are driven to rotate in opposite directions on rotation axes parallel to each other.

  Preferably, the roots type dry pump may include a plurality of the rotor chambers connected in cascade. The compression unit may include a plurality of roots type dry pumps connected in cascade.

  Preferably, the heat circulation system includes: an expander that converts a force generated by expansion of the gas exchanged in the heat exchange unit into a predetermined type of power; and the power of the expander is used to compress the gas. You may have a power transmission part which transmits to the said roots type dry pump as a part of required motive power. In this case, the expander may include a roots-type dry pump including a rotor chamber that houses a pair of rotors that are driven to rotate in opposite directions on mutually parallel rotating shafts.

  A thermal circulation system according to a second aspect of the present invention includes a drying chamber that dries an object to be dried put in a room, a dust collection unit that removes dust contained in the gas exhausted from the drying chamber, The first compression unit that compresses the gas from which dust has been removed in the dust collection unit, and the heat generated by the compression of the gas by the compression unit are applied to the drying object that is input into the drying chamber. A first heat exchanging unit to transmit; an expander that converts a force generated by expansion of the gas that has passed through the first heat exchanging unit into power of a predetermined type; and the power of the expander to compress the gas A power transmission unit that transmits to the first compression unit as part of the required power; and a second compression unit that compresses the gas expanded in the expander and feeds the gas into the interior of the drying chamber. Are driven to rotate in opposite directions on the rotation axes parallel to each other. Including Roots type dry pump having a rotor chamber in which a pair of rotors is housed.

  Preferably, the heat circulation system may include a second heat exchange unit that transmits heat of the gas that has passed through the first heat exchange unit to the gas supplied to the second compression unit.

  Preferably, at least one of the expander and the second compression unit may include a roots type dry pump including a rotor chamber that houses a pair of rotors that are rotationally driven in opposite directions on rotation axes parallel to each other. .

  Preferably, the thermal circulation system includes a gas / liquid separator that removes liquid contained in the gas sucked into the expander, and / or a gas / liquid that removes liquid contained in the gas exhausted from the expander. You may have a separation part.

  According to the present invention, by using a roots-type dry pump for adiabatic compression of gas, it is possible to efficiently compress a gas having a relatively small flow rate (such as water vapor) and effectively reduce exergy loss.

It is a figure which shows an example of a structure of the thermal circulation system which concerns on embodiment of this invention. It is a figure showing the cross section perpendicular | vertical to a rotating shaft which shows an example of a structure of the pump which comprises a compressor. It is a figure showing the cross section parallel to a rotating shaft which shows an example of a structure of the pump which comprises a compressor. It is a figure which shows an example of a structure of the thermal circulation system which concerns on other embodiment of this invention. It is a figure which shows an example of a structure of the thermal circulation system which concerns on other embodiment of this invention. It is a figure which shows an example of a structure of the thermal circulation system which concerns on other embodiment of this invention. It is a figure which shows an example of a structure of the thermal circulation system which concerns on other embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating an example of a configuration of a thermal circulation system according to an embodiment of the present invention.
The heat circulation system according to this embodiment includes a heat exchanging unit 20, a processing unit 50, a compressor 10, a motor 40, and a cooling unit 25. The heat exchange unit 20 is an example of a heat exchange unit in the present invention. The unit including the compressor 10 and the motor 40 is an example of a compression unit in the present invention.

  The compressor 10 compresses the gas (water vapor or the like) flowing out from the processing unit 50 to increase the temperature. The compressor 10 includes a roots type dry pump (FIGS. 2 and 3) which will be described later. The motor 40 generates driving power to be supplied to the compressor 10.

  The processing unit 50 is a device that performs predetermined processing such as distillation, concentration, drying, chemical synthesis, and gas separation based on the substance heated in the heat exchanging unit 20, and flows out the gas generated by the processing. To do.

  The heat exchanging unit 20 transmits heat generated by the compression of the gas by the compressor 10 to a substance used for generating gas in the processing unit 50. Thereby, the substance supplied to the processing unit 50 is heated.

  The cooling unit 25 cools the gas flowing out from the heat exchange unit 20 and collects it as a liquid.

  In the thermal circulation system shown in FIG. 1, predetermined processes such as distillation, concentration, drying, chemical synthesis, and gas separation are performed. As a heat source of the heating process in the process, the gas flowing out from the processing unit 50 is compressed. The resulting heat is used. That is, a heat treatment is performed on a substance to be supplied, and when a predetermined process (distillation, drying, etc.) is performed using the heated substance, a gas is generated by the compressor 10. Is compressed, the temperature of the gas rises, and the heat is reused as a heat source for the heating process of the substance. Since the gas with a low exergy rate is compressed to increase the temperature and reused as a heat source for the heating process, energy consumption can be reduced compared to a method in which heat energy for the heating process is separately added. it can.

  2 and 3 are diagrams showing an example of the configuration of a pump (roots type dry pump) that constitutes the compressor 10. 2 shows a cross section perpendicular to the rotating shaft 12 of the rotor (11a to 11f), and FIG. 3 shows a cross section parallel to the rotating shaft 12.

  The pump shown in FIGS. 2 and 3 has two rotating shafts 12 held in parallel inside a casing 19 forming a main body. The rotating shaft 12 is rotatably supported by bearings 15 and 16 provided at both ends of the casing 19.

  In the casing 19, a plurality of (six in the example of FIG. 3) cascaded rotor chambers 13 each containing two rotors (11a to 11f) are formed. The six rotor chambers 13 are arranged side by side in the axial direction of the rotating shaft 12, and the two rotating shafts 12 pass through these rotor chambers 13. Each of the rotor chambers 13 includes an intake port and an exhaust port, and the exhaust port of the former rotor chamber 13 is connected to the intake port of the subsequent rotor chamber 13 via the communication path 14. The gas supplied from the intake passage 17 to the first-stage rotor chamber 13 is compressed by the rotation of the rotors (11a to 11f) in the six rotor chambers 13, and is discharged from the final-stage rotor chamber 13 through the exhaust passage 18.

  The two rotors (11a to 11f) accommodated in the same rotor chamber 13 have the same shape and dimensions. The two rotors (11a to 11f) are respectively fixed to the rotating shaft 12, and rotate in opposite directions while maintaining a slight gap. Further, the two rotors (11a to 11f) rotate while maintaining a slight gap without contacting the inner wall of the rotor chamber 13.

  Power is transmitted from the drive shaft of the motor 40 to the two rotary shafts 12 via a power transmission mechanism (not shown). For example, the two rotary shafts 12 are coupled via a timing gear so as to rotate in opposite directions, and one rotary shaft 12 is coupled to the drive shaft of the motor 40.

  According to the pump (roots type dry pump) shown in FIGS. 2 and 3, when the two rotating shafts 12 are rotated in the opposite directions by driving the motor 40, the two rotors (11 a to 11 f) are slightly in the rotor chamber 13. Rotate in opposite directions while maintaining a clear gap. As a result, the gas supplied to the intake port of the rotor chamber 13 is confined in the gap between the inner wall of the rotor chamber 13 and the rotor (11a to 11f) and is carried to the exhaust port of the rotor chamber 13. As a result, the gas is sequentially carried from the first-stage rotor chamber 13 to the final-stage rotor chamber 13, and the pressure of the gas on the exhaust side becomes higher than that on the intake side of the pump.

  As described above, according to the thermal circulation system according to the present embodiment, since a roots type dry pump is used as the compressor 10 that performs adiabatic compression for raising the temperature of a gas, a centrifugal rotary type or screw type compressor is used. As compared with the above, even when the gas flow rate is small, the power consumption can be suppressed and the compression can be performed efficiently. Thereby, the loss in the thermal circulation system which handles a comparatively small flow rate can further be reduced, and energy saving property can be improved.

  In addition, according to the present embodiment, by using a roots type dry pump, compression can be performed to a pressure higher than atmospheric pressure at a temperature of hundreds of degrees Celsius or higher, so that relatively small heat using steam is used. A circulation system can be constructed.

  In addition, this invention is not limited to embodiment mentioned above, Various modifications are included.

FIG. 4 is a diagram illustrating an example of a configuration of a thermal circulation system according to another embodiment of the present invention.
The thermal circulation system shown in FIG. 4 has the same configuration (compressor 10, motor 40, heat exchange unit 20, cooling unit 25, processing unit 50) as the thermal circulation system shown in FIG. 22.

The valve 22 adjusts the amount of gas supplied to the compressor 10 via the heat exchange unit 20.
The compressor 10 compresses the gas heated in the heat exchange unit 20 and supplies the compressed gas to the processing unit 50A.
The processing unit 50A performs predetermined processing such as distillation, concentration, drying, chemical synthesis, and gas separation based on the gas compressed by the compressor 10.
The heat exchanging unit 20 transfers the heat of the substance (gas or liquid) flowing out from the processing unit 50 </ b> A to the gas on the intake side of the compressor 10 to heat it.
According to the thermal circulation system shown in FIG. 4, the temperature of the gas supplied to the processing unit 50A rises due to the compression of the compressor 10, and the heat of the gas flowing out from the processing unit 50A is used to intake the compressor 10 The side gas is heated. Therefore, in the heat circulation system shown in FIG. 4 as well, as in the heat circulation system shown in FIG. 1, the gas having a low exergy rate is compressed and increased in temperature to be reused as a heat source for the heating process. , Energy consumption can be effectively reduced.

FIG. 5 is a diagram illustrating an example of a configuration of a heat circulation system according to another embodiment of the present invention.
The heat circulation system shown in FIG. 5 has the same configuration (compressor 10, motor 40, heat exchange unit 20, processing unit 50) as the heat circulation system shown in FIG. 1, and includes the expander 30 and the power transmission unit 45. Have.
The expander 30 converts the force generated by the expansion of the gas exchanged in the heat exchanging unit 20 into a predetermined type of power. The expander 30 includes, for example, a roots type dry pump. The roots type dry pump has the same configuration as the pump shown in FIGS. 2 and 3, for example, and converts the force generated by the expansion of gas into the rotational power of the rotary shaft.
The power transmission unit 45 transmits the power recovered from the gas expansion force in the expander 30 to the pump of the compressor 10 as a part of the power required for gas compression.
According to the thermal circulation system shown in FIG. 5, the power generated by the expansion of the gas is recovered as power in the expander 30 and reused for the compression of the gas, thereby reducing the power consumption of the motor 40 that drives the compressor 10. can do.

FIG. 6 is a diagram illustrating an example of a configuration of a heat circulation system according to another embodiment of the present invention.
The heat circulation system shown in FIG. 6 has the same configuration (compressor 10, motor 40, heat exchange unit 20, processing unit 50, expander 30, power transmission unit 45) as the heat circulation system shown in FIG. It has a processing unit 50B and a heat exchange unit 20B.
The block including the processing unit 50 and the processing unit 50B performs predetermined processing such as distillation, concentration, drying, chemical synthesis, gas separation, etc., but the processing unit 50B has a substance (gas) that flows in / out compared to the processing unit 50. Or the temperature of the liquid) is low. Therefore, in the heat circulation system shown in FIG. 6, the heat of the gas flowing out of the heat exchanging unit 20 and having a slightly lowered temperature is used for heating the substance (gas or liquid) supplied to the processing unit 50B. The heat exchanging unit 20B transmits the heat of the gas flowing out from the heat exchanging unit 20 to the substance supplied to the processing unit 50B and heats it. The expander 30 converts the expansion of the gas flowing out from the heat exchange unit 20B into power.

According to the heat circulation system shown in FIG. 6, the heat of the gas heated in the compressor 10 is reused for heating processes having different temperatures in a plurality of heat exchange units, thereby improving the utilization efficiency of heat energy. Can contribute to reducing energy consumption.
In the example of FIG. 6, the number of stages of the heat exchanger is two, but it is also possible to recycle heat energy by providing three or more stages of heat exchangers in the cascade.

  FIG. 7 is a diagram showing an example of the configuration of a thermal circulation system according to another embodiment of the present invention, and shows an example applied to a system for drying biomass.

The thermal circulation system shown in FIG. 7 includes compressors 10 and 95, an expander 30, a motor 40, a power transmission unit 45, a drying device 60, heat exchangers 65 and 90, a dust collector 70, Gas-liquid separators 80 and 85 are included.
The drying chamber of the drying device 60 is an example of a drying chamber in the present invention.
The dust collector 70 is an example of a dust collector in the present invention.
The compressor 10 is an example of a first compression unit in the present invention.
The heat exchanger 65 is an example of a first heat exchange unit in the present invention.
The expander 30 is an example of an expander in the present invention.
The power transmission unit 45 is an example of a power transmission unit in the present invention.
The compressor 95 is an example of a second compression unit in the present invention.
The heat exchanger 90 is an example of a second heat exchange unit.
The gas-liquid separators 80 and 85 are an example of a gas-liquid separator in the present invention.

  The drying device 60 is a device that dries biomass supplied from the outside. The drying chamber of the drying device 60 is heated by the heat exchanger 65, and air is sent from the compressor 95 to the lower side of the drying chamber. When biomass and a fluidized material are put into this drying chamber, the biomass is heated in a fluidized bed state, and moisture is evaporated and dried.

  The dust collector 70 removes dust (biomass and fluidized material particles) contained in the air exhausted from the drying device 60. The biomass particles separated and removed from the exhaust gas by the dust collector 70 may be returned to the dried biomass discharged from the drying device 60.

The compressor 10 compresses the gas (air containing water vapor) from which dust has been removed in the dust collector 70 to increase the temperature. The compressor 10 includes, for example, a roots type dry pump (FIGS. 2 and 3).
The motor 40 generates driving power to be supplied to the compressor 10.

  The heat exchanging unit 65 transmits the heat generated as the gas is compressed by the compressor 10 to the biomass charged into the drying chamber of the drying device 60. Thereby, the biomass put into the drying chamber of the drying device 60 is heated.

  The heat exchange unit 90 transmits the heat of the gas (air containing water vapor) sent from the compressor 10 and passed through the heat exchange unit 65 to the air on the intake side of the compressor 95. Thereby, the air sent from the compressor 95 to the drying chamber is preheated.

  The gas-liquid separator 80 removes liquid (moisture) contained in the gas (air containing water vapor) that has passed through the heat exchange unit 65 and the heat exchange unit 90.

The expander 30 converts the force generated by the expansion of the high-pressure gas (air containing water vapor) that has passed through the heat exchangers 65 and 90 and the gas-liquid separator 80 into a predetermined type of power. The expander 30 includes, for example, a roots type dry pump. The roots type dry pump has the same configuration as the pump shown in FIGS. 2 and 3, for example, and converts the force generated by the expansion of the gas into the rotational power of the rotary shaft.
The power transmission unit 45 transmits the power recovered from the gas expansion force in the expander 30 to the pump of the compressor 10 as a part of the power required for gas compression.

  The compressor 95 compresses the gas expanded in the expander 30 and sends it to the drying chamber of the drying device 60. The compressor 95 includes, for example, a roots type dry pump (FIGS. 2 and 3).

  The gas-liquid separator 85 removes liquid (moisture) contained in the gas (air containing water vapor) exhausted from the expander 30.

The operation of the heat circulation system shown in FIG. 7 having the above-described configuration will be described.
When biomass and fluidized material are charged into the drying device 60 and heated air is sent from the compressor 95 into the drying device 60, the biomass comes into contact with the heated air while spreading in the drying device 60 in a fluidized bed state. The water contained in the biomass evaporates. The water vapor generated by heating the biomass in the drying device 60 is collected in the dust collector and then supplied to the compressor 10 and compressed. The steam whose temperature has been increased by the compression is returned to the heat exchanger 65 inside the drying device 60 and used for heating the biomass. The steam that has passed through the heat exchanger 65 further passes through the heat exchanger 90, and the air supplied to the compressor 95 is preheated by the heat of the steam. The vapor whose temperature has been lowered by passing through the two heat exchangers 65 and 90 is separated into a gas component and a liquid component in the gas-liquid separator 80, and the gas component is supplied to the expander 30. When the gas component expands in the expander 30, the force generated by the expansion is converted into a predetermined type of power and used for work of the compressor 10 via the power transmission unit 45. The gas component expanded in the expander 30 is further removed in the gas-liquid separator 85, then preheated in the heat exchanger 90, and returned to the compressor 95.

  According to the heat circulation system shown in FIG. 7, heat is generated by compressing the gas (air containing water vapor) exhausted from the drying device 60 to a high pressure in the compressor 10, and the heat is generated in the drying device 60. Used for drying biomass. In this way, a gas with a low exergy rate is compressed to increase the temperature and used as a heat source for the heating process. Therefore, compared to the conventional method that uses the heat generated by the combustion of fuel for drying. Energy loss can be suppressed, and significant energy consumption can be saved.

  Further, according to the heat circulation system shown in FIG. 7, since the gas used for heating the drying device 60 passes through the heat exchanger 90, the air before being supplied to the drying device 60 is preheated. Energy use efficiency can be improved by suppressing unnecessary energy loss.

  Furthermore, according to the thermal circulation system shown in FIG. 7, the power generated by the expansion of the gas is recovered as power in the expander 30 and reused for the compression of the gas, so that the power consumption of the motor 40 that drives the compressor 10 Therefore, the energy use efficiency can be further increased.

  In the above-described embodiment, an example is described in which a roots type dry pump including a plurality of rotor chambers cascaded in multiple stages is used for gas compression, but the present invention is not limited to this example. In another embodiment of the present invention, a roots-type dry pump (mechanical booster pump) that operates in a one-stage rotor chamber may be used for gas compression, or a roots-type dry pump including an arbitrary number of stages of rotor chambers. A plurality of units may be connected in cascade.

DESCRIPTION OF SYMBOLS 10 ... Compressor, 11a-11f ... Rotor, 12 ... Rotating shaft, 13 ... Rotor chamber, 14 ... Communication passage, 15, 16 ... Bearing, 17 ... Intake passage, 18 ... Exhaust passage, 19 ... Casing, 20 ... Heat exchange , 25 ... Cooling unit, 30 ... Expander, 40 ... Motor, 45 ... Power transmission unit, 50 ... Processing unit, 60 ... Drying device, 65, 90 ... Heat exchanger, 80, 85 ... Gas-liquid separator, 95 ... compressor.

Claims (9)

A compression section for compressing gas;
A heat exchanging unit that transfers heat generated by the compression of the gas by the compression unit to a gas that is sent to the compression unit or a substance that is used to generate a gas that is sent to the compression unit, and
The compression unit includes a roots-type dry pump including a rotor chamber that houses a pair of rotors that are driven to rotate in opposite directions on rotation axes parallel to each other.
Thermal circulation system. The roots type dry pump includes a plurality of the rotor chambers connected in cascade.
The thermal circulation system according to claim 1. The compression unit includes a plurality of roots type dry pumps connected in cascade.
The thermal circulation system according to claim 1 or 2. An expander that converts the force generated by the expansion of the gas heat-exchanged in the heat exchange unit into a predetermined type of power;
A power transmission unit that transmits the power of the expander to the roots-type dry pump as part of the power required to compress the gas.
The thermal circulation system as described in any one of Claims 1 thru | or 3. The expander includes a roots-type dry pump including a rotor chamber that houses a pair of rotors that are driven to rotate in opposite directions on mutually parallel rotating shafts.
The thermal circulation system according to claim 4. A drying chamber for drying an object to be dried put in the room;
A dust collecting section for removing dust contained in the gas exhausted from the drying chamber;
A first compression section that compresses the gas from which dust has been removed in the dust collection section;
A first heat exchanging unit that transfers heat generated by the compression of the gas by the compression unit to the object to be dried that is put into the drying chamber;
An expander that converts the force generated by the expansion of the gas that has passed through the first heat exchange section into a predetermined type of power;
A power transmission unit that transmits the power of the expander to the first compression unit as a part of the power required to compress the gas;
A second compression section that compresses the gas expanded in the expander and feeds the gas into the drying chamber;
Have
The first compression unit includes a roots-type dry pump including a rotor chamber that houses a pair of rotors that are driven to rotate in opposite directions on rotation axes parallel to each other.
Thermal circulation system. Having a second heat exchange section that transfers the heat of the gas that has passed through the first heat exchange section to the gas supplied to the second compression section,
The thermal circulation system according to claim 6. At least one of the expander and the second compression unit includes a roots-type dry pump including a rotor chamber that houses a pair of rotors that are rotationally driven in opposite directions on rotation axes parallel to each other.
The thermal circulation system according to claim 6 or 7. A gas-liquid separator that removes liquid contained in the gas sucked into the expander, and / or a gas-liquid separator that removes liquid contained in the gas exhausted from the expander.
The thermal circulation system according to any one of claims 6 to 8.