JP2005168940A - Apparatus and method for dry-cleaning of heat driving circulation type with supercritical carbon dioxide fluid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problems: (1) no synthetic chemical substance is used as a detergent, (2) no washing auxiliary is used, (3) chemical substance remaining in clothes is removed as much as possible, and (4) a causative substance of an allergy or the one to worsen the allergy is removed and sterilized, while maintaining the washing capability equal or superior to conventional dry-cleaning. <P>SOLUTION: The dry-cleaning apparatus for cleaning washed objects such as clothes, bedclothes and furs, etc. comprises at least one sprayer with a heating mechanism for making carbon dioxide in the detergent in the supercritical state for spraying carbon dioxide in the supercritical state to a washing tub, the washing tub loaded with washed objects for washing the washed objects in the supercritical state, an evaporator for heating/evaporating the liquefied carbon dioxide after washing and separating/removing stain components, a condenser for liquefying carbon dioxide gasified by the evaporator, and a liquid reservoir tank for reserving the condensed and liquefied carbon dioxide and feeding the carbon dioxide to the sprayer from time to time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

    The present invention relates to a dry cleaning apparatus for clothes and the like and a method for removing chemical substances, bacteria, fungi and the like to the limit using supercritical carbon dioxide as a cleaning agent.

  At present, so-called dry cleaning is widely used, and the cleaning power of dirt is almost satisfactory. However, since chemical substances such as cleaning agents and cleaning aids are harmful to the environment and health, their use is prohibited in the near future. Furthermore, it is known that people with allergies such as chemical hypersensitivity and atopy, which are increasing recently, are aggravated by wearing clothes washed by dry cleaning.

In order to improve the above, Patent Document 1 and Patent Document 2 propose dry cleaning with liquid carbon dioxide, but the cleaning power is insufficient as compared with conventional dry cleaning, and the use of a cleaning aid is essential. However, there is a drawback that it is difficult to obtain a good cleaning aid. However, compared to conventional methods, the amount of chemical substances used is greatly reduced, and the drying process is unnecessary.
Special table 2001-514337 Special Table 2002-543951

As the latest method, dry cleaning with supercritical carbon dioxide has been proposed. Since carbon dioxide in the supercritical state has high diffusion and penetrating power and excellent solubility, it has the potential to be cleaned with only carbon dioxide in the supercritical state without using a cleaning aid. However, in order to bring carbon dioxide into a supercritical state, it is necessary to make it mechanically high pressure by a compressor. Problems such as accumulation and adhesion to the object to be cleaned are inevitable. In order to improve this point, Patent Document 3 proposes a super-subcritical fluid processing system that can efficiently form a high-pressure field such as supercritical or subcritical in a high-pressure fluid process without using a special compression device. Because of the expectation that it has the possibility of cleaning in it, it is assumed that a cleaning device will be installed as a treatment container, and it is proposed in advance as a future study subject, but it can also be used for practical cleaning It has not yet been confirmed whether or not.
JP2003-126673

The present invention is intended to solve the following problems while maintaining a cleaning capability equivalent to or higher than that of conventional dry cleaning.
1) Supercritical carbon dioxide dry cleaning equipment that does not generate pollutants 2) Establishment of dry cleaning that does not use any synthetic chemicals as cleaning agents 3) Cleaning that does not use any cleaning auxiliaries 4) Chemical substances remaining on clothing Cleaning that can be removed as much as possible 5) Cleaning that can remove mold, chemicals, and sterilize bacteria that cause allergy or worsen allergies

  Here, the present inventors have a heating mechanism that brings the carbon dioxide of the cleaning agent into a supercritical state, and discharges and injects the carbon dioxide that has been put into the supercritical state into the cleaning tank; A cleaning tank for cleaning in a supercritical state, and an evaporator for heating and evaporating carbon dioxide in a liquid state after cleaning to separate and remove dirt components; a condenser for liquefying carbon dioxide gasified by the evaporator; A dry cleaning device that cleans laundry, clothes, bedding, fur, etc., which consists of a liquid storage tank that stores carbon dioxide condensed into liquid and supplies carbon dioxide to the discharger as needed The supercritical carbon dioxide is brought into a critical state and discharged from at least one discharger into a cleaning tank filled with the cleaning object, and the cleaning object is washed with supercritical carbon dioxide. The evaporated carbon dioxide is heated and evaporated to separate and remove the dirt components with an evaporator. The carbon dioxide gasified with the evaporator is liquefied with a condenser, and the condensed carbon dioxide is stored in a liquid tank and discharged as needed. Finding a dry cleaning method for laundry, clothes, bedding, fur, and other laundry objects that consist of supplying carbon dioxide to the clothes. Further, the dry cleaning device is for clothes, bedding, fur, etc. To find out that the dry cleaning method is also suitable for those who are allergic to chemical substances and those for allergies such as atopy. It came.

  The effects of the present invention are enumerated as follows. That is, although it seems to be due to the excellent solubility, diffusibility, and permeability of the supercritical carbon dioxide used in the present invention, a high detergency can be obtained without a cleaning aid. In addition, since it is a closed system that does not require a mechanical means such as a pump to generate high pressure and does not use a high pressure pump, there is no contamination of the cleaning agent or metal powder, and operation without noise can be performed. By utilizing the extremely large coefficient of thermal expansion at the supercritical temperature, a pressure difference is induced by heating, and carbon dioxide as a cleaning agent is injected as a driving force into the cleaning tank at a high pressure so that efficient cleaning can be performed. By using low latent heat of vaporization in the subcritical region, efficient solvent evaporation / condensation quickly and completely separates the contaminants eluted in the solvent, circulates / regenerates the solvent, and always keeps it fresh. Can be done. Since a heating method with good controllability is used for pressure increase, fine cleaning conditions can be set in accordance with the dirt material of the object to be cleaned. By purging supercritical carbon dioxide from the washing tank to the low-pressure evaporation tank, bacteria and mold can be killed, and supercritical carbon dioxide from the washing tank is adiabatically purged to the low-pressure evaporation tank. After that, by heating and evaporating carbon dioxide, liquid dirt components such as water washed away from clothes and solid dirt components can be separated and removed from carbon dioxide, and the removed dirt components are at the bottom of the evaporator. More timely discharge. As a result of the above, the dry cleaning using supercritical carbon dioxide according to the present invention has a good cleaning effect, solves the problem of solvent residue on the object to be cleaned such as clothing, the texture of the finished object to be cleaned is good, and the cleaning itself In addition, it is gentle to humans and has no problems of chemical burns or skin irritation.

  As a dry cleaning device for washing laundry, bedding, fur and other laundry objects according to the present invention, it has a heating mechanism for making carbon dioxide as a cleaning agent in a supercritical state, and discharges carbon dioxide in a supercritical state into a washing tank. At least one discharger, a cleaning tank that is filled with an object to be cleaned and cleaned in a supercritical state, an evaporator that heats and evaporates liquid carbon dioxide after cleaning and separates and removes dirt components, and an evaporator A description will be given below of a condenser comprising a condenser that liquefies gasified carbon dioxide and a liquid reservoir tank that accumulates carbon dioxide condensed in a liquid state and supplies carbon dioxide to the discharger as needed.

  Table 1 shows the flow of the heat-driven forced circulation supercritical carbon dioxide dry cleaning apparatus, and Table 2 shows the specifications of the main components of the apparatus.

In the example, the flow of the apparatus is shown in Table 1, and the cleaning by the three continuous discharges by two units of the discharger 1 and the discharger 2 was performed without using the discharger 3 and the discharger 4. Each state of the process over time will be described below.
“Initial setting”: CO 2 (abbreviation for carbon dioxide) is supplied to the condenser, reservoir, and discharger.
“To-be-washed object filling”: The object to be washed is put into a washing tank and sealed. Pour CO2 from the liquid storage tank into the washing tank to remove air and fill the washing tank with CO2.
“Start discharging to cleaning tank”: CO2 of the discharger 1 is heated and pressurized at high speed, and when the set pressure reaches 10 MPa, CO2 in a supercritical state automatically starts discharging to the cleaning tank.
“Discharge continuation”: The discharge is continued by overheating so as to keep the pressure of the discharger 1 at 10 MPa. The CO2 that exits the washing tank is adiabatically expanded and discharged to the evaporator, and is stored in the liquid tank through the condenser.
“End of discharge of the discharge device 1”: After the discharge is continued for 10 minutes from the discharge device 1, the heating is stopped and the discharge is ended. “Starting discharge from the discharger 2 to the cleaning tank”: When the set pressure becomes 10 MPa by rapidly expanding the CO2 of the discharger 2, the supercritical CO2 is continuously discharged into the cleaning tank.
“Discontinuation”: The discharge is continued while maintaining the pressure of the discharger 2 at 10 MPa.
“Discharge end of discharge device 2”: After discharging is continued for 10 minutes from the discharge device 2, heating is stopped and discharge is ended. During this time, CO 2 is supplied from the liquid storage tank to the discharger 1.
“Start and continue discharge from discharge device 1 to cleaning tank”: Switch from discharge device 2 to discharge device 1. Supercritical CO2 is continuously discharged into the washing tank, and the washing tank pressure is kept at 10 MPa. “End of discharge of the discharge device 1”: After the discharge from the discharge device 1 is continued for 10 minutes, the heating is stopped, the discharge is ended, and the cleaning is completed. The low pressure CO2 in the washing tank is collected in the low pressure collection tank.
“Removal of object to be cleaned”: Residual CO 2 remaining in the cleaning tank is discharged to atmospheric pressure.
“Washing completed”: The object to be cleaned is taken out of the cleaning tank.

  FIG. 1 shows changes in pressure in the cleaning tank, the discharge device 1, the discharge device 2, and the evaporator in the first embodiment. That is, the discharger quickly raised the set pressure to 10 MPa, and the discharge was continued while maintaining 10 MPa. When switching the dispenser, the pressure was switched quickly and the discharge was switched. In the washing tank, although a slight pressure drop was observed when switching the discharge, 10 MPa in a supercritical state was stably maintained.

  Moreover, what is shown in FIG. 2 about the temperature change of the washing tank in Example 1, the discharge device 1, the discharge device 2, and the evaporator is observed, and since the discharge device during discharge maintains 10 MPa, it raises to the maximum temperature of 190 degreeC. It was warm. Also, the cleaning tank quickly started and maintained supercritical cleaning immediately after the start of discharge, exceeding the critical condition of CO 2 of 31 ° C. in a short time.

  Using the same cleaning apparatus as in Example 1, cleaning was performed by continuously discharging each time from the discharger 1 and the discharger 2. No cleaning aids are used in the cleaning with only CO2. In evaluating the results, the results were compared with a general dry cleaning method. As a general-purpose dry cleaning cleaning method, a commercial dry cleaning machine was used, and cleaning was performed under commercial cleaning conditions. As the cleaning agent, a commercially available cleaning agent, petroleum-based cleaning agent or perchlorethylene (official name of tetrachloroethylene) was used, and a commercial cleaning aid was used. Further, a sample of 5 cm × 4 c cotton and wool was used as a test cloth, and two types of contaminants were given to the sample. Contaminant A was liquid paraffin and oil red, and contaminant B was beef tallow and oil red. In the washing experiment, three identical contaminated cloths were sewn to three places on a clean plain cotton cloth. The washing experiment was performed twice, and the reflectance was measured immediately after the washing to determine the degree of washing. The results are shown in Table 3. Here, it is assumed that the one having a high reflectance has a high degree of cleaning.

  The reflectance here is an average value of the three test cloths. From the result, the dirt by the dry cleaning with supercritical CO2 is clearly less stained than that by the general-purpose petroleum-based dry cleaning. It is equivalent to or slightly better than general-purpose perchlorethylene dry cleaning. From these results, it was demonstrated that dry cleaning using only supercritical CO 2 without using any chemical substances such as cleaning aids has a cleaning power equivalent to or higher than that of conventional general-purpose dry cleaning.

  As a test garment, a commercially available cotton trainer for adults was used, and the garment washed under each condition was kept in a 65 liter sealed container kept at 28 ° C. for 24 hours, and the vaporized organic compound (VOC) After the emission was in a steady state, 1.5 liters of air in the container was sucked and VOC was sucked and collected in the column, and then the VOC component was quantitatively analyzed by a GC-mass spectrometer. The results are shown in Table 4. In the table, the numbers in parentheses indicate negative values.

    In Table 4, NO. 1 is the measurement result of clothes as purchased, NO. No. 2 is a dry garment obtained by adding commercial cleaning aids to petroleum-based dry cleaning cleaners (commonly called sol cleaning), NO. No. 3 was obtained by cleaning the purchased clothes using the cleaning device according to the present invention by the triple discharge of the cleaning method according to the present invention. No. 4 was purchased clothes washed with water and detergent for business use, NO. No. 5 was obtained by washing the purchased clothing with water using a commercial water washing detergent and auxiliary agent and further sol washing, NO. No. 6 is a product obtained by washing a purchased garment with water using a commercial water washing detergent and an auxiliary agent, followed by sol washing, and then washing by triple discharge of the washing method according to the present invention.

  As a result, it was confirmed that the VOC remaining after the supercritical CO2 dry cleaning was extremely small. Moreover, the amount of VOCs present could be greatly reduced by washing newly purchased products and clothes washed by conventional general-purpose dry cleaning using the method according to the present invention.

  A worn garment was washed with the method according to the present invention for a woman who was very sensitive to chemicals and suffered from severe chemical sensitivity and was given a wear rating. It is known that this woman can only be worn after a reliable manufacturer's product has been washed several times with hot water. Clothes washed by a general-purpose dry cleaning method using ordinary petroleum-based or perchlorethylene as a cleaning agent become harsh and cannot be worn or taken indoors. However, when this patient's jacket and skirt were washed by the method according to the present invention and evaluated by the patient for wearing, it was evaluated that there was no problem at all.

  Since chemical substances emitted from clothing directly touch the skin or are gasified near the inhalation port such as the nostrils, they are taken into the body, so the VOC of clothing needs to be much lower than the VOC allowable concentration that causes general sick house etc. There is. According to this example, it was confirmed that the cleaning method according to the present invention is an extremely excellent cleaning method for chemical-sensitive patients, which completely eliminates VOC.

  Patients with allergies (so-called atopy) as well as chemical substance hypersensitivity are also sensitive to chemical substances and cannot wear clothing made of chemical fibers other than natural fibers such as cotton, or wash items other than water. It has been. Moreover, if bacteria remain in the washed clothes, contact with the affected part of atopy by wearing may cause suppuration. It is known that microorganisms are sterilized by carbon dioxide, and it is said that sterilization is promoted as the pressure is increased, the treatment time is longer, and the pressure is rapidly lowered after the treatment with carbon dioxide. As described above, according to the cleaning of the present invention, the removal of chemical substances from clothing is sufficiently advanced, the pressure is increased to a supercritical state of 10 MPa, and the cleaning time is continuous for a plurality of dispensers. It can be controlled freely by operating, and after washing is completed, the garment is rapidly depressurized, so that sterilization can proceed almost completely. Therefore, it can be said that the cleaning method according to the present invention is an extremely excellent cleaning method for atopic patients.

  The dry cleaning using supercritical carbon dioxide according to the present invention has a good cleaning effect, eliminates the problem of residual chemical substances on the object to be cleaned such as clothing, the texture of the finished object to be cleaned is good, and the cleaning itself is also in the environment Since it is gentle to humans and has no problems of chemical burns or skin irritation, it also has an excellent working environment, so it is expected to be widely used as a next-generation dry cleaning industry cleaning method instead of conventional general-purpose dry cleaning. It is considered a breakthrough.

The pressure change in the washing tank, the discharger 1, the discharger 2, and the evaporator in Example 1 is shown. The temperature change in the washing tank in Example 1, the discharge device 1, the discharge device 2, and the evaporator is shown.

Claims (6)

Equipped with a heating mechanism that brings the carbon dioxide of the cleaning agent into a supercritical state. A cleaning tank for cleaning, an evaporator for heating and evaporating carbon dioxide in a liquid state after cleaning to separate and remove dirt components, a condenser for liquefying carbon dioxide gasified by the evaporator, and storing carbon dioxide condensed in liquid form A dry cleaning device for washing clothes such as clothes, bedding, fur, etc., which comprises a liquid reservoir for supplying carbon dioxide to a discharger as needed. The cleaning agent carbon dioxide is brought into a supercritical state by a heating mechanism, and the supercritical carbon dioxide is discharged from at least one discharger into a cleaning tank filled with the cleaning object to bring the cleaning object into a supercritical state. The carbon dioxide is washed with carbon dioxide, the liquid carbon dioxide after washing is evaporated by heating, the dirt components are separated and removed by the evaporator, and the carbon dioxide gasified by the evaporator is liquefied by the condenser and condensed into liquid form. A method for dry-cleaning laundry, bedding, fur, and other objects to be washed, which comprises storing carbon dioxide in a liquid storage tank and supplying carbon dioxide to a discharger as needed. The dry cleaning apparatus according to claim 1, wherein the laundry, bedding, fur and other laundry objects are for chemical sensitive persons. The dry cleaning apparatus according to claim 1, wherein the laundry, bedding, fur and other laundry objects are for allergic subjects. The dry cleaning method according to claim 2, wherein the laundry, bedding, fur and other objects to be washed are for chemical sensitive persons. The dry cleaning method according to claim 2, wherein the laundry, bedding, fur and other laundry objects are for allergic subjects.

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