KR0136987B1 - Treatment of food sludge by thermal degradation with catalyst - Google Patents

Abstract

The present invention relates to a method for treating food waste by catalytic pyrolysis, and more particularly, to heat food waste generated in a kitchen at a temperature of 50 to 275 ° C. under a catalyst such as acidic clay having a layered structure for 1 to 2 hours. The present invention relates to a method for treating food waste, which is rapidly and cleanly reduced by pyrolysis and recycled.

Description

How to Treat Food Waste by Catalytic Pyrolysis

1 is a process diagram schematically illustrating a process of treating food waste in accordance with the method of the present invention.

＊ Description of symbols for main parts of the drawings ＊

1,5 filter 2 high pressure reactor

3: electric heater 4: cooler

6: gas storage tank

The present invention relates to a method for treating food waste by catalytic pyrolysis, and more particularly, to heat food waste generated in a kitchen at a temperature of 50 to 275 ° C. under a catalyst such as acidic clay having a layered structure for 1 to 2 hours. The present invention relates to a method for treating food waste, which is rapidly and cleanly reduced by pyrolysis and recycled. More specifically, the present invention relates to the development of a technology for reducing waste of food waste of 70% or more by high speed by pyrolysis under a catalyst and converting it into solid fuel having a water content of 10% or less and recycling it. In recent years, the amount of waste generated in our country is 24,000 tons / day, and the amount of waste to be processed is enormous, and the government is struggling to deal with the increase of about 10% every year. In particular, food waste accounts for 16.7% of the total waste, which is the second highest after industrial waste. Food waste has a lower recycling rate than industrial waste and has a high water content of at least 70%. This waste has the characteristics that must be treated. Therefore, until now, more than 95% of food waste has been relied on landfills for rapid and inexpensive treatment.However, in recent years, landfill pollution has been measured and announced by landfill leachate, and landfill law has been raised due to rising land prices or opposition from landfill residents. The cost of processing will rise so that it will be almost impossible to use. In addition, as a treatment method other than reclamation, there is a method used as livestock feed. This method has been used without processing for a few years ago, but in recent years, most of the hog farmers are not practical due to difficulties in diseases and separate collection. It is recognized as a treatment. In order to solve the above problems, a drying machine for drying food is developed and marketed. However, since the water content is higher than 70% and the latent heat of water, that is, the heat of vaporization is very high at 539 kcal / g, the cost of treating food waste is high. There is a high problem. Composting, which is used as one of the food waste disposal methods, takes about 60 days and thus requires the storage of food waste generated in this period, that is, landfills. It is judged to be a difficult method to use. Rapid fermentative enzymes have been developed and used as a method to solve this problem, but this case also takes about 15 days, which is still not a satisfactory technology. In general, feed and compost have high added value, so food waste and composting technology is preferred, but domestic food waste consists mainly of vegetables, so the carbon ratio of nitrogen compared to the standard for feed and compost is 25 Due to the lack of%, feed and compost produced from food waste are considered to have low added value, and their biggest drawback is low processing speed. Incineration is the most common way to solve this problem. However, the incineration method has the advantage that the treatment speed is fast, but the food waste has a high water content as mentioned above, and considering the heat of vaporization of water, the treatment cost is high. Mechanical dehydration technology has been developed to reduce the moisture content of food waste, but it is difficult to reduce the moisture content below 70% because it is almost impossible to remove moisture in the cell. On the other hand, a pyrolysis liquefaction technology has been developed as a method for the treatment of high water content waste. In other words, the high-temperature, high-pressure pyrolysis liquefaction technology proposed by Yokoyama, Japan, etc. is a technology developed to convert sewage waste (sludge) with a moisture content of 3,000 tons per day in Tokyo to be converted into energy called oil (joumal). of Chemical Engineering of Japan, 23 (1), 6-11 (1990)) The operating conditions are about 250 ℃ and 100 atmospheres, and the reaction conditions are violent, which implies the risk of operation. The high economical efficiency is not only high, causing secondary environmental pollution, but also high equipment and operating costs. The inventors of the present invention have been trying to overcome the problems of the high temperature, high pressure pyrolysis technology as a result of the development of low temperature, low pressure pyrolysis under a catalyst such as acidic clay having a layered structure, the present invention is unlike the conventional pyrolysis method Despite the waste being treated in the catalyst, the volume is reduced at high speeds, reducing the composition of gases and water-soluble oils to reduce secondary environmental pollutants, minimizing costs by increasing the yield of solids produced and recycling them to energy sources. It can be made, it is characterized by high economic efficiency compared to other treatment methods such as high temperature pyrolysis method. According to the present invention, food waste is not changed at high speed, and food waste is pyrolyzed at a low temperature as possible under a catalyst to suppress the generation of water-soluble oils and gases, thereby reducing the secondary environmental pollution causing factors such as water quality and general pollution. The aim is to provide a more economical way to re-use energy into energy. Hereinafter, the present invention will be described in detail.

The present invention is characterized in that the food waste is filtered and then decomposed and reduced by heating at a temperature of 50 to 275 ° C. for 1 to 2 hours in the presence of a catalyst in a high pressure reactor (2), and then cooled and filtered again to separate the solids and filtrates. It relates to a method for treating food waste by catalytic pyrolysis. Referring to the present invention in more detail as follows. The present invention is directed to a method for treating food waste which can prevent environmental pollution and recycle resources by pyrolyzing food in the presence of a catalyst to reduce its volume, extract oil from the filtrate and use it as an energy source of the method of the present invention. The raw material which can be processed by the pyrolysis method of the present invention is a waste containing all foods such as radishes, cabbage, rice, fish, meat, etc., and the content of moisture contained in the raw material is 105 ° C. It is calculated by measuring ignition loss, but the moisture content of the raw material used in the present invention is 80% or more. As the catalyst used in the present invention, a layered acidic clay, clay, montmorillonite, kaolin or bentonite may be used in an amount of about 5 parts by weight based on 100 parts by weight of food waste, and by using such a catalyst, decomposition of food waste may be performed. By facilitating it, the recycling of wastes can be made more effective. The invention will be described step by step in accordance with the accompanying drawings, FIG. First, filter the food waste in the filter (1), add a catalyst such as acidic clay, and then put it in a high-pressure reactor (2) with an electric heater (3) is sealed and warmed for 1 to 2 hours at 50-275 ℃ Keep it. At this time, the reaction proceeds in a state where the reaction pressure is automatically maintained at 59 atm from 0.2 atm. If the reaction temperature is out of this range, the dehydration reaction does not occur by pyrolysis or the increase in the amount of gas generated by pyrolysis and the amount of water-soluble oil is increased, thereby increasing the amount of substances causing secondary environmental pollution of water and air pollution. Is emerging. The food waste is decomposed under the above conditions and then cooled to room temperature in the cooler (4). The amount of gas produced during the reaction was measured by a gas meter after reducing the pressure in the gas reservoir 6, but it was negligible up to 300 ° C. and increased rapidly at temperatures higher than that. This fact is well understood by the pyrolysis liquefaction method. The gas component was determined by gas chromatography, and the main component was methane. The cooled product is filtered through a filter (5) to separate the solids and the filtrate (wastewater), and the filtrate is extracted twice with 50 ml of carbon tetrachloride (CCI₄) or dichloromethane (CH₂CI₂) as a solvent to give a dark brown high viscosity from the filtrate. Oil was extracted and the amount of water pollution, the secondary environmental pollution factor, was compared. The calorific value of the solid residue is measured after drying the filtered solid at a temperature of 105 ° C. for 5 hours. The solids separated from the product and the highly viscous oil extracted from the filtrate can be recycled as fuel in the food waste treatment process of the present invention. As such, the present invention is a method for easily treating food waste by pyrolysis, which is a breakthrough in treating food waste that is increasing explosively, and may contribute to prevention of environmental pollution, which is a problem worldwide recently, as well as treated reactions. This is very useful in that the product can be recycled as an energy source. Hereinafter, the present invention will be described in detail with reference to the following examples, which are not intended to limit the present invention.

Example 1 600 g of radish (95% water content) and 0.5 g of acidic clay (catalyst), which are the most contained in food waste, were placed in a 2 liter high-pressure reactor and reacted at 200 ° C. (reaction pressure: 16.4 atm) for 1 hour. After cooling to room temperature, the reaction was filtered to separate the solid and the filtrate. The filtrate was extracted twice with 50 ml of dichloromethane solvent to extract oil from the filtrate. After extraction, the solvent was recovered by an evaporator to give a viscous oil. The results obtained from the experiment are as follows. The calorific value of the double solids was measured by the spring calorimeter and the energy supply efficiency was calculated as follows.

Solids: 11.5g (calories: 4519 Kcal / g) oil: 7.0g (calories: 8000Kcal / g) Volume reduction rate: 98% Energy supply efficiency:

32.9%

Comparative Example 1 600 g of radish (water content 95%) was placed in a 2 L high-pressure reactor, and then reacted at 300 ° C. (reaction pressure: 86.0 atm) for 1 hour, and then cooled to room temperature. The reaction was filtered to separate the solid and the filtrate, and the filtrate was extracted twice with 50 ml of dichloromethane solvent to extract oil from the filtrate. After extraction, the solvent was recovered by an evaporator to obtain a viscous oil. The results obtained from the experiment are as follows. Solids: 5.0g (calories: 6750 Kcal / g) oil: 1.4g (calories: 8000Kcal / g) Volume reduction rate: 99% Energy supply efficiency: 16.3%

Comparative Example 2 600g (95% water content) of radish most contained in food waste was placed in a 2L high-pressure reactor, reacted at 200 ° C (reaction pressure: 16.4 atm) for 1 hour, cooled to room temperature and filtered. The solid was separated into a filtrate. The filtrate was extracted with 50 ml of dichloromethane solvent to extract oil from the filtrate. The results obtained from the experiment are as follows. Solids: 5.9g (calories: 5359 Kcal / g) oil: 0.6g (calories: 8000Kcal / g) Volume reduction rate: 99% Energy supply efficiency: 20.8%

Example 2 Food waste obtained in a restaurant was filtered under reduced pressure using an aspirator, and food waste having a water content of 80% was used as a raw material. The volatile content of this raw material was 98.9%, which was 12.75% fat, 20.2% protein and 76% fiber. 600 g of the food waste and 0.5 g of acidic clay were placed in a high pressure reactor and reacted at 200 ° C. (reaction pressure: 16.4 atm) for 1 hour, and then cooled to room temperature. The reaction was filtered to separate solid and filtrate. The filtrate was extracted twice with 50 ml of dichloromethane solvent to extract oil from the filtrate. The results obtained from the experiment are as follows. Analysis of protein, fat, carbohydrate and fiber contained in the food waste was measured by JIS, respectively. Solids: 57.9g (calories: 5616 Kcal / g) oil: 0.7g (calories: 8000Kcal / g) Volume reduction rate: 90% Energy supply efficiency: 189.0%

Example 3 Food waste obtained in a restaurant was filtered under reduced pressure using an aspirator, and food waste having a water content of 80% was used as a raw material. The volatile content of this raw material was 98.9%, which was 12.75% fat, 20.2% protein and 76% fiber. 600 g of the food waste and 0.5 g of montmorillonite were placed in a high pressure reactor and reacted at 200 ° C. (reaction pressure: 16.4 atm) for 1 hour, and then cooled to room temperature. The reaction was filtered to separate solid and filtrate. The filtrate was extracted twice with 50 ml of dichloromethane solvent to extract oil from the filtrate.

After extraction, the solvent was recovered by an evaporator to obtain a viscous oil. The results obtained from the experiment are as follows. Analysis of protein, fat, carbohydrate and fiber contained in the food waste was measured by JIS, respectively. Solids: 52.1g (calories: 5532 Kcal / g) oil: 0.5g (calories: 8000Kcal / g) Volume reduction rate: 91% Energy supply efficiency: 167.7% Example 4 Decompression of food waste obtained in a restaurant using an aspirator After filtration, food waste having a water content of 80% was used as a raw material. The volatile content of this raw material was 98.9%, which was 12.75% fat, 20.2% protein and 76% fiber. 600 g of the food waste and 0.5 g of kaolin were placed in a high pressure reactor and reacted at 200 ° C. (reaction pressure: 16.4 atm) for 1 hour, and then cooled to room temperature. The reaction was filtered to separate solid and filtrate. The filtrate was extracted twice with 50 ml of dichloromethane solvent to extract oil from the filtrate. After extraction, the solvent was recovered by an evaporator to obtain a viscous oil. The results obtained from the experiment are as follows. Analysis of protein, fat, carbohydrate and fiber contained in the food waste was measured by JIS, respectively. Solids: 53.2g (calories: 5574 Kcal / g) oil: 0.6g (calories: 8000Kcal / g) Volume reduction rate: 91% Energy supply efficiency: 172.9% Example 5 Decompression of food waste obtained in restaurants using an aspirator After filtration, food waste having a water content of 80% was used as a raw material. The volatile content of this raw material was 98.9%, which was 12.75% fat, 20.2% protein and 76% fiber. 600 g of the food waste and 0.5 g of acidic clay were placed in a high pressure reactor and reacted at 200 ° C. (reaction pressure: 16.4 atm) for 1 hour, and then cooled to room temperature. The reaction was filtered to separate solid and filtrate. The filtrate was extracted twice with 50 ml of dichloromethane solvent to extract oil from the filtrate. After extraction, the solvent was recovered by an evaporator to obtain a viscous oil. The results obtained from the experiment are as follows. Analysis of protein, fat, carbohydrate and fiber contained in the food waste was measured by JIS, respectively. Solids: 57.9g (calories: 5616 Kcal / g) oil: 0.4g (calories: 8000Kcal / g) Volume reduction rate: 90% Energy supply efficiency: 188.4%

Comparative Example 3 After 600 g of the food waste used in Example 2 was placed in a high pressure reactor, the reaction was carried out at 200 ° C. (reaction pressure: 16.4 atm) under a catalyst for 1 hour, and then cooled to room temperature. The reaction was filtered to separate solid and filtrate. The filtrate was extracted with 50 ml of dichloromethane solvent to extract oil from the filtrate. After extraction, the solvent was recovered by an evaporator to obtain a viscous oil. The results obtained from the experiment are as follows. Solids: 30.1g (calories: 5609 Kcal / g) oil: 1.1g (calories: 8000Kcal / g) Volume reduction rate: 95% Energy supply efficiency: 101.5%

Claims (2)

After filtering the food waste, in the presence of a catalyst in a high-pressure reactor in the presence of a catalyst, it is decomposed and reduced by heating for 1 to 2 hours at a temperature of 200 ° C. or lower, and then cooled and filtered again to separate the solid and the filtrate, and the filtrate is carbon tetrachloride (CCI₄) or Extracting oil using dichloromethane (CH₂CI₂) as a solvent, and then using this as a fuel for the pyrolysis process together with the solids. The method of claim 1, wherein the catalyst is acidic clay, clay, montmorillonite, kaolin or bentonite.