JP-7856258-B2 - Operating method of an indirect pressurized steam recompression type heat pump treatment device

Inventors

• 山本 岳身
• 八木 翼
• 山崎 日出夫

Assignees

• 株式会社大川原製作所

Dates

Publication Date

20260511

Application Date

20220622

Claims (3)

1. A method for operating a heat pump type processing apparatus, which includes a continuous conduction heat transfer dryer equipped with a heating device inside the main shell, configured to evaporate moisture by bringing the workpiece into contact with the heat transfer surface of the heating device, The heat pump type treatment apparatus is configured to re-evaporate the heat transfer medium that has been discharged from the heating device as condensate after its temperature has dropped, then to increase its pressure and temperature using a compressor, and then to supply it back to the heating device for repeated use . Furthermore, this heating device is designed to dry the workpiece by exchanging heat with a heat transfer medium . The heat of the carrier gas containing water vapor evaporated from the material to be processed, which is discharged from the exhaust port formed in the main body shell, is taken into the heat transfer medium in the drain state in the heat exchanger and re-evaporated. Furthermore, the compressor is provided with two compressors in series. First, the first-stage compressor reduces the pressure upstream of the first-stage compressor to promote the re-evaporation of the condensate heat transfer medium, while simultaneously making the pressure on the suction side of the second-stage compressor positive. In an operating method for an indirect pressurized steam recompression type heat pump treatment device, in which the second stage compressor subsequently increases the pressure so that the temperature of the heat transfer medium reaches a desired value, The rotational speed of the first-stage compressor is controlled so that the pressure on the primary side of the first-stage compressor reaches a predetermined value, thereby controlling the evaporation rate of the heat transfer medium in the heat exchanger. The conditions are defined as "regenerative steam ratio,""second stage compressor speed,""first stage compressor speed," and "first stage compressor suction pressure." A method for operating an indirect pressurized steam recompression type heat pump treatment device , characterized by performing fuzzy inference with the conclusion being "a set value manipulation amount for the suction pressure of the first stage compressor".
2. The method for operating an indirect pressurized steam recompression type heat pump treatment apparatus according to claim 1, wherein a mechanism for releasing the heat transfer medium to the outside is provided between the first-stage compressor and the second-stage compressor , and when the pressure of the heating medium between the first-stage compressor and the second-stage compressor exceeds a predetermined value, a portion of the heat transfer medium is released to the outside.
3. The heat exchanger is configured to allow outside air to be introduced into the carrier gas supplied to it. When there is excess thermal energy in the heat transfer medium discharged from the second stage compressor, A method for operating an indirect pressurized steam recompression type heat pump treatment apparatus according to claim 1 or 2 , characterized in that outside air is introduced into the carrier gas supplied to the heat exchanger to reduce heat recovery to the heat transfer medium.

Description

The present invention relates to a method and apparatus for drying and concentrating materials such as muddy, cake-like, powdery, or granular materials, as well as liquid materials. More particularly, it relates to an operation method for an indirect pressurized steam recompression type heat pump treatment apparatus in which the heat of a carrier gas containing water vapor evaporated from the material to be processed, discharged from the exhaust port, lowers the temperature of the heat transfer medium discharged from the heating device in a drain state, causing it to re-evaporate and be circulated for use as a heat source for drying the material to be processed. Recently, environmental conservation efforts have become more prevalent, and companies and other organizations are drying general waste such as food waste and food processing residues, as well as sewage sludge, to reduce its volume and prevent spoilage before recycling or disposal. One type of equipment used for this drying process is a heat pump treatment device that uses the steam generated from the material being treated as a heat source; this type of device is called a direct pressurization type (steam recompression type). On the other hand, indirect pressurized heat pump treatment systems often utilize refrigeration systems that use fluorocarbons or similar heat transfer fluids. These systems require the entire system, from the dryer to the vacuum exhaust system, to be operated under vacuum. The dryer becomes a vacuum dryer, requiring a robust body that can withstand external pressure and a special system for discharging the dried product. For this reason, there have been no previous examples of indirect pressurized steam recompression type heat pumps being put into practical use in conduction heat transfer dryers. Therefore, the applicant has developed a novel steam recompression type heat pump treatment apparatus that can be configured on a small scale, can perform drying and concentration operations on the material to be treated continuously, can reduce power consumption, and does not cause contamination of the condensed water. A patent application has already been filed for this invention, and it has been evaluated and registered (see Patent Document 1). Furthermore, the applicant has been continuously conducting research and development on a steam recompression type heat pump treatment apparatus, attempting various improvements. Based on the idea of using superheated steam instead of the conventional outside air used as the carrier gas, the applicant has devised an invention that allows for continuous drying of the material to be treated under atmospheric pressure and significantly reduces the manufacturing cost of the apparatus. This invention has already been filed for patent application and has been registered (see Patent Document 2). Furthermore, the applicant has developed a device that can resolve the aforementioned problems such as compressor failure by applying the above invention, which is characterized by the use of superheated steam as a carrier gas, to an indirect pressurized steam recompression type heat pump treatment device, which differs from the direct pressurized steam recompression type. This device has already been patented, and this invention has also been evaluated and registered (see Patent Document 3). The applicant has continued research and development of this indirect pressurized steam recompression type heat pump treatment apparatus, and has come to recognize that there is room for improvement in the following areas. Firstly, in the case of a heating device where the heat transfer medium discharged from the heating device is in a condensate state, the re-evaporation of this condensate becomes insufficient. Secondly, the suction side of the compressor becomes a negative pressure, which is lower than atmospheric pressure, causing a decrease in efficiency. Furthermore, in this case, the discharge pressure of the compressor decreases, reducing the overall efficiency of the device. To solve these problems, the applicant has developed a novel drying and concentration method and apparatus that uses a two-stage compressor configuration, with the first-stage compressor used exclusively for reducing pressure on the upstream (suction) side to improve the evaporation of the condensate-state heat transfer medium, while simultaneously creating positive pressure on the downstream (discharge) side. This avoids a decrease in the efficiency of the second-stage compressor and significantly improves the overall efficiency of the apparatus. A patent application for this method has already been filed, and this invention has also been evaluated and registered (see Patent Document 4 and Figure 8 of this application). Subsequently, as the practical application and operation of heat pump type processing equipment equipped with the continuous conduction heat transfer dryer disclosed in Patent Document 4 progressed, it became apparent that