KR20020016369A - Method for the production of synthesis gas from food sludge - Google Patents

Abstract

PURPOSE: Provided is a method for producing synthetic gas from waste food which can economically performed in a shorten period of process time at a lower consumption of energy and can readily treat waste food to produce synthetic gases at a high energy efficiency. CONSTITUTION: The method comprises (i) separation step for separating solid ingredients from waste water by pyrolysis of waste food with a catalyst in a low temperature reactor under a controlled temperature and vapor pressure, (ii) extraction step for extracting oil from the waste water by a catalytic decomposition reaction with a catalyst circulated through a vaporizer, and (iii) production step for producing synthetic gases by gasification of the solid carbon including oil and solids produced in the extraction step(ii) in a gas reactor. The pyrolysis of waste food with a catalyst is performed at a temperature of 100 to 300 deg.C and a vapor pressure of 1 to 25 atm for 1 to 3 hours. The extraction step is performed by drying the product of the pyrolysis at 105 deg.C for 5 hours to produce solid material and extracting filtrate with dichloromethane. The gas production step is performed at 300 to 1200 deg.C.

Description

Method for the production of synthesis gas from food sludge}

The present invention relates to a method for obtaining synthesis gas from food waste, and more particularly, food waste is heated and pressurized in a low temperature reactor to separate the solids and the filtrate (wastewater) by pyrolysis method, and the solidified carbon and the solids from the solids and filtrate. By separating the oil and then producing a synthesis gas through gasification reaction, it almost eliminates the moisture contained in the food waste to reduce the food waste and to obtain a reusable synthesis gas from the solidified carbon generated therein.

Recently, the amount of waste generated in Korea is increasing to about 24,000 tons per day, and various methods are known for treating such wastes.

In particular, food wastes account for 16.7% of the total weight of the wastes, and since the water content is about 70% within the food wastes, the food wastes are easily decayed and bad odors are seriously raised.

In addition, the food waste contains a large amount of fat-fat components such as carbohydrates, fats, proteins, cellulose, as well as water, and thus has difficulty in treating oil leachate.

This food waste is treated through landfill, which is the most common method, but this method has a problem of ensuring sufficient landfill as the amount of food waste is taken out, especially the leachate generated from food waste in the landfill But it has contaminated groundwater.

One of the methods of treating food waste, which has been used continuously until recently, is to use food waste as feed. When using food waste as feed, it has the advantage that it can be used as feed without additional processing, but it is not used anymore because it is not practical due to concerns about the disease occurrence or transportation cost of livestock fed with food waste as feed. It is true.

Another way to use food waste as feed is to dry food waste to reduce its water content and then feed it. However, this drying method was determined to be economically unreasonable due to the high moisture content of food waste, which requires a lot of heat of vaporization (539 cal / g) to evaporate water.

Another food treatment method is a method of composting and using food waste. Since the composting method takes about 60 days to compost food waste, a large amount of storage and storage place for storing compostable food waste is needed to process a large amount of food waste. It is difficult to apply to the situation of Korea where the storage space is narrow.

Of course, in order to shorten the time it takes to compost food waste, many enzymes are developed to ferment food waste as a property, and the time required for composting has been shortened to about 15 days. The problem is raised because there is no satisfactory technology in dealing with the odor pollution generated by the company.

In addition, the composting treatment method in Korea, because more than half of the vegetables contained in the food waste, the carbon ratio of nitrogen required for composting is 10 to 25% less than the standard value, sawdust to supplement this In addition, chaff powder, rice straw or sewage sludge is added to increase the initial organic matter content has arisen.

Another food waste disposal method is a biological waste disposal method. However, this biological treatment method has a considerable amount of organic sludge produced as a by-product after treating food waste, which causes more serious pollution due to landfill or soil pollution caused by the treatment of the organic sludge.

Incineration is another method of treating food waste, but it is not economical because it requires a lot of heat of vaporization due to evaporation of water as food waste is used as feed because it has to incinerate food with high moisture content.

The present invention has been made in view of this point, by reducing the overall loss of waste by evaporating water from food waste with a high moisture content, and can obtain a synthetic gas that can be recycled using the carbon and oil generated in this process. In order to ensure this, food waste and catalyst are introduced into a low temperature reactor, and the heating and steam pressure are controlled to cause pyrolysis reaction to obtain a solid, and the filtrate obtained from the reaction is extracted with oil using a solvent. The present invention provides a method for obtaining synthesis gas from food waste, comprising a gas generation process of providing a solidified carbon composed of solids to a gas reactor to obtain a synthesis gas by gasification reaction.

In a preferred embodiment of the present invention, the pyrolysis process is characterized in that it induces a pyrolysis reaction for 1-3 hours at a steam pressure of 1-25 atm at 100 ℃ to 300 ℃.

In addition, the pyrolysis reaction is CxHyOz It is characterized by consisting of carbon carbon + H ₂ O + CO + CO ₂ .

In addition, the extraction process is characterized in that it comprises a drying for 5 hours at a temperature of 105 ℃ to obtain a solid as a solid carbon.

In addition, the catalyst is characterized in that the layered zeolite catalyst.

In addition, the gas generation process is carried out under the conditions of 300 ℃-1200 ℃, the reaction scheme is CxHyOz It is characterized by being represented by H ₂ + CO + CO ₂ + CH ₄ .

1 is an explanatory diagram for explaining a method for obtaining a synthesis gas according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: low temperature reactor 20: gas reactor

30: evaporator

Hereinafter, with reference to the accompanying drawings, the configuration and effect of the present invention will be described.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an explanatory view for explaining a method for obtaining a synthesis gas according to the present invention, wherein 10 is a low temperature reactor, 20 is a gas reactor, and 30 is an evaporator.

In the present invention, the catalyst is put together with the food waste into the low temperature reactor (10), where the pyrolysis reaction separates the solids and the filtrate (wastewater), and the filtrate is separated with oil using a dichloromethane catalyst. By gasifying the solidified carbon obtained from the oil and the solid in the gas mixer 20, a synthesis gas can be obtained.

In more detail, the low temperature reactor 10 in which the separation process is performed is a reactor that receives nitrogen gas together with food waste from a general feeder for processing food waste to cause a pyrolysis reaction.

Here, the low temperature reactor 10 is maintained in a constant temperature state by applying heat in a sealed state, the reaction pressure in the sealed interior is maintained by the water vapor pressure.

Of course, for this purpose, the low temperature reactor 10 is provided with a temperature controller and a heater, in particular, the temperature controller maintains the internal temperature of the low temperature reactor 10 to 100 ~ 300 ℃, the heater is generated from food waste The vaporized water and the water supplied from the outside are vaporized to maintain the reactor internal pressure at 5 to 25 atm for 1 to 3 hours.

Accordingly, the pyrolysis reaction occurs in the low temperature reactor 10, and the pyrolysis reaction formula is as shown in Scheme 1.

Solid carbon + H ₂ O + CO + CO ₂

As shown in Scheme 1, in the separation process using the pyrolysis reaction, solids (solid carbon), which are mostly solids composed of coal, and filtrates (waste water) are obtained from food waste.

Here, the catalytic reaction is preferably added to the low-temperature reactor 10 directly to the catalyst to greatly increase the production of solidified carbon and to enable the gasification reaction using the solidified carbon obtained here.

The catalytic reaction thermally decomposes a high molecular weight food waste consisting of a carbon component, a hydrogen component, and an oxygen component to produce a low molecular weight solidified carbon.

Here, the dichloromethane used as a catalyst is used to obtain a viscous earthy brown oil by extracting an organic component from an aqueous solution, and the dichloromethane used in this way is evaporated through an evaporator 30 and then catalyzed in oil. It can be cycled to be used as.

In addition, the catalytic pyrolysis reaction includes a process for obtaining a solid residue from a solid, which is dried at a temperature of 150 ° C. for 5 hours to obtain solid carbon, and the solid carbon is used as an energy source.

In this way, the oil obtained by the catalytic reaction in the filtrate is used to produce a synthesis gas by gas reaction with the solidified carbon.

As such, after the separation and extraction processes are completed, a gas-forming reaction is performed to generate a mixed gas by mixing the solidified carbon and the viscous oil.

The gas generation process is made in the gas reactor 20, where the carbonization and oil produced in the extraction process are added together to cause a gasification reaction.

In this case, the solidified carbon is mainly identified as hydrogen, carbon monoxide, and methane as a result of measuring the weight and components thereof by gas meter and gas chromatography.

H ₂ + CO + CO ₂ + CH ₄

Scheme 2 is obtained by reacting at 300 ° C. to 1200 ° C. to obtain a synthesis gas (hydrogen component and carbon monoxide component).

Therefore, the food wastes have a significant drop in moisture content during the decomposition and extraction process, and thus obtain a solid residue that can be used with the required calories. The efficiency will be improved.

Hereinafter, an embodiment according to the present invention will be described.

Here, the content of moisture contained in the raw material is obtained by measuring the ignition loss (solidition loss) of the solid at 105 ℃, Ash is measured after burning at 600 ℃. In addition, the carbon and nitrogen contents were measured by elemental analysis, and the calories were measured by bomb calorimeter, and the analysis of protein, fat, carbohydrate and fiber contained in food waste was carried out by respective JIS methods. Measured. In addition, the volume reduction rate is obtained by the following Equation 1.

[Equation 1]

Example 1

600 g of radishes containing 95% water content in the food waste were put in a low temperature reactor, heated to 200 ° C., and then cooled to room temperature after 1 hour of reaction without a catalyst. The reaction was filtered to separate the solids and the filtrate, and then the filtrate was extracted twice with 50 ml of methylene chloride and oil was obtained. The results obtained by this experiment are as follows.

Solid water: 5.9g (calories: 5359cal / g)

Oil: 0.6g

Volume reduction rate: 99%

Example 2

600 g of radish having a water content of 95% and 1.5 g of zeolite as a catalyst were put in a low temperature reactor, heated to 200 ° C., and then cooled to room temperature after 1 hour of reaction under a catalyst. The reaction was filtered to separate the solids and the filtrate, and then the filtrate was extracted twice with 50 ml of methylene chloride and oil was obtained. The results obtained by this experiment are as follows.

Solid water: 8.3g (calories: 3195cal / g)

Oil: 1.4g

Volume reduction rate: 99%

Example 3

600 g of dried radish (water content 95%) and 0.5 g of acidic clay catalyst were put in a low temperature reactor for one day at room temperature, heated to 200 ° C., and then cooled to room temperature after 1 hour reaction under a catalyst. The reaction was filtered to separate the solids and the filtrate, and then the filtrate was extracted twice with 50 ml of methylene chloride and oil was obtained. The results obtained by this experiment are as follows.

Solid water: 11.5g (calories: 4519cal / g)

Oil: 0.7g

Volume reduction rate: 99%

Example 4

600 g of dried radish (water content of 95%) and 0.5 g of bentonite catalyst were put in a low temperature reactor for one day at room temperature, heated to 200 ° C., and then cooled to room temperature after 1 hour of reaction under a catalyst. The reaction was filtered to separate the solids and the filtrate, and then the filtrate was extracted twice with 50 ml of methylene chloride and oil was obtained. The results obtained by this experiment are as follows.

Solid water: 9.2g (calories: 4679cal / g)

Oil: 0.8g

Volume reduction rate: 99%

Example 5

The food waste obtained from the restaurant was filtered through an apierator, and 600g of food waste containing 80% water, 98.9% volatiles, 12.75% fat, 20.2% protein, and 76.0% fiber was placed in a low-temperature reactor at 200 ° C. After heating, the mixture was cooled to room temperature after 1 hour of reaction without a catalyst. The reaction was filtered to separate the solids and the filtrate, and then the filtrate was extracted twice with 50 ml of methylene chloride and oil was obtained. The results obtained by this experiment are as follows.

Solid water: 30.1g (calories: 5609cal / g)

Oil: 1.1g

Volume reduction rate: 98%

Example 6

The food waste obtained from the restaurant was filtered through an acipator, and 600 g of food waste containing 80% water, 98.9% volatiles, 12.75% fat, 20.2% protein, and 76.0% fiber with 0.5 g catalytic acid clay. After heating to 200 ℃ in a low-temperature reactor, the reaction was cooled to room temperature after 1 hour. The reaction was filtered to separate the solids and the filtrate, and then the filtrate was extracted twice with 50 ml of methylene chloride and oil was obtained. The results obtained by this experiment are as follows.

Solid water: 35.3g (calories: 4086cal / g)

Oil ; 1.2 g

Volume reduction rate: 98%

The composition of the synthesis gas obtained by producing a synthesis gas containing a large amount of hydrogen and carbon monoxide in a high yield by gas-reacting the solidified carbon and oil in a gas reactor at a temperature of 500 ~ 800 ℃ is shown in Table 1.

Reaction temperature (℃) Gas conversion rate Hydrogen carbon monoxide methane carbon dioxide 500 23.2 23.2 25.1 4.2 47.5 600 43.3 45.6 8.7 15.8 29.9 700 69.0 64.1 5.2 12.8 23.3 800 81.1 66.6 11.5 9.1 12.8 900 97.7 60.6 26.9 3.9 8.6

As described above, the present invention introduces food waste and catalyst into a low-temperature reactor, generates a thermal decomposition reaction by controlling heating and steam pressure, and separates solids and filtrate (wastewater) by using a catalyst circulated through an evaporator. Food waste, characterized in that the extraction process of extracting oil from the filtrate (wastewater) through a catalytic decomposition reaction, and the production process of obtaining a synthesis gas by gasification reaction by providing a solidified carbon consisting of the oil and solids to the gas reactor By providing a method for obtaining a synthesis gas from the above, the following effects can be obtained.

1) The reaction time that occurs in each process is short, which reduces energy consumption, such as evaporation of water, and has the effect of shortening the working time.

2) As the result of each process is significantly reduced in volume, it is easy to dispose of food waste, and solid residues and syngas can be used as energy, thereby improving energy supply efficiency.

3) The produced syngas can be used as a chemical fuel to produce fine chemical intermediates through catalytic reactions or clean fuels such as methanol or gasoline.

Claims (6)

Separation of solids and filtrate (wastewater) by feeding food waste and catalyst into the low temperature reactor and controlling the heating and steam pressure to cause pyrolysis reaction; An extraction process of extracting oil from the filtrate (waste water) through a catalytic decomposition reaction using a catalyst circulated through an evaporator, A method of obtaining syngas from food waste, comprising producing a solid carbon composed of oil and solids in a gas reactor to obtain syngas by gasification. The method of claim 1, wherein the pyrolysis process induces a pyrolysis reaction for 1-3 hours at a steam pressure of 1-25 atm at 100 ° C. to 300 ° C. 3. The method of claim 1 or 2, wherein the pyrolysis reaction is CxHyOz A method for obtaining syngas from food waste, characterized in that reacted with solid carbon + H ₂ O + CO + CO ₂ . The method of claim 1, wherein the extraction process is dried at a temperature of 105 ° C. for 5 hours to obtain carbon solids from solids, and the filtrate is extracted with dichloromethane. The method of claim 1 wherein the catalyst is a layered zeolite catalyst. According to claim 1, wherein the gas generation process is carried out under the conditions of 300 ℃-1200 ℃, the reaction scheme is CxHyOz It is characterized by being represented by H ₂ + CO + CO ₂ + CH ₄ .