JPH0586374A - Decomposition of carbohydrate into combustible gas - Google Patents

Abstract

PURPOSE:To obtain a combustible gas useful as a fuel or a chemical raw material by decomposing a carbohydrate by heating it together with a catalyst and water or salt water. CONSTITUTION:10 pts.wt. Al(OH)3 as a catalyst is added to a suspension prepared by thoroughly mixing 350 pts.wt. water with 8.45 pts.wt. cellulose, and the resulting mixture is fed to an autoclave and reacted by heating to 370-380 deg.C under agitation to decompose the cellulose into a combustible gas mixture comprising H2, CO, hydrocarbons, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for decomposing carbohydrates into combustible gases, and more particularly to decomposing carbohydrates into a combustible gas mixture of CO ₂ and H ₂ , CO, hydrocarbons and the like. It is about the method.

[0002]

2. Description of the Related Art Generally, when a hydrocarbon is heated, it is dehydrated or thermally decomposed to generate water vapor, CO ₂ , and combustible gases, and carbonized. It is well known that when wood or herbs containing a large amount of carbohydrates are subjected to dry distillation, combustible gases such as organic acid, organic solvent, CO _2, CO, CH ₄ , and H ₂ are generated. However, although the organic acid and the flammable gas obtained in this manner are partially put into practical use, they are not general industrial products. Carbohydrates are organic compounds and are classified as carbon and water compounds, so it is thought that they can be decomposed into CO ₂ and hydrocarbons by selecting an appropriate catalyst. By the way, regarding the origin of petroleum and flammable natural gas (hereinafter referred to as petroleum), there have been an inorganic theory (non-biological origin) and an organic theory (biological origin) since ancient times, and various contents have been proposed. Looking at the composition and endowment of petroleum,
The organic theory has gained much support today.

According to the organic theory, petroleum is a raw material of plants that once thrived on land and the bodies of living things that lived in seawater. These are carried by rivers, or they become sediments as they are and are deposited on the seabed together. Under a reducing environment with little oxygen, organisms are decomposed by the action of anaerobic bacteria, etc., and a sedimentary layer (petroleum source rock) rich in organic matter is formed. It is believed that these will be converted to petroleum after a geological time lapse under the influence of geopressure and geothermal heat. A large number of people are studying methods for producing petroleum from organisms, which are raw materials for petroleum, especially plants that are predominant in quantity. If the origin of petroleum is known, the maximum effect can be expected for these exploration activities. An object of the present invention is to provide a method for decomposing a carbohydrate as a starting material into a combustible gas. or,
It is possible to conserve the resources of the plant that is said to be a raw material. That is, wood, cotton, and processed products thereof can be converted into petroleum and reused at the final stage after use. However, even in the laboratory, petroleum has never been produced from genuine plant substances.

[0004]

[Problems to be Solved by the Invention]
The inventors have found that carbohydrates, basically CH ₄ , C ₂ H ₆ ,
Lower hydrocarbons and CO ₂ in decomposing result of investigation of the combustible natural gas similar etc., the reaction is a catalytic reaction, the catalyst was found to be the same material as the major component of sea water is effective. As a result of searching for catalysts in a wider range, it was found that not only dissolved components of seawater, but also derivatives thereof and substances such as homologous elements are effective as catalysts for decomposing carbohydrates into the above gases. The composition of these were produced as a catalyst gas, other CO _2,
The present invention has been completed as a result of finding that there is a substance containing a large amount of CO, H _{2 and the} like and a substance containing a large amount of hydrocarbons, and further examining the correspondence between the catalyst and the gas composition.

[0005]

That is, the present invention is a method for decomposing a carbohydrate into a combustible gas and CO ₂ at a high temperature in the presence of a catalyst and water or brine. As a catalyst, Mg, Ca, S of IIA group (2A group) in the periodic table of elements
Zn of r, Ba, IIB group (2B group), and IIIB group (3B
The oxides, hydroxides, carbonates, sulphates, sulphites, sulphides or mixtures of these metals such as Al of the group) are used. The present invention is a method for decomposing a carbohydrate into a flammable gas mixture, and the produced gas is industrially useful as a fuel or a chemical raw material if CO ₂ is removed by a known technique, if necessary. The present invention attempts to materialize some of the chemical reactions that can be considered in the organic theory of the origin of petroleum, and according to this, biological remnants move underground and are heated to the ground temperature to form petroleum. It is thought to have changed. Therefore, it is not always necessary for the organic matter to be decomposed by the action of anaerobic bacteria or the like, and if the reaction conditions are the same, the chemical reaction proceeds, so that geological time is not necessarily required.

[0006] In the experiment for the purpose of converting the plant body into petroleum, cellulose, which is a basic constituent component of the plant, was selected as the plant body initially used. Cellulose was manufactured by Toyo Roshi Kaisha, Ltd. and had a purity of 99.9%. First, the reaction between petroleum source rock and cellulose was investigated. The main components of this rock are quartz, feldspar, and clay minerals such as kaolin and montmorillonite, which are so-called mudstones. Minor components were organic substances, carbon, sulfur, iron oxide, etc. Powder of source rock and cellulose suspended in water were charged into an autoclave, and the reaction was tried at high temperature and high pressure. The pressure at this time is the water vapor pressure. Although minerals of this kind are active in the decomposition and isomerization of hydrocarbons, only carbonization was observed in the reaction with cellulose and other carbohydrates. Therefore, if there is a catalyst that is active in the reaction of converting carbohydrates to petroleum, it can be inferred that it is not a mineral of this type and that it is only a carrier for that catalyst.

Therefore, as a result of trying to find the catalyst, Mg, Ca, Sr, Ba of the IIA group in the periodic table of the elements,
Addition of metal oxides, hydroxides, carbonates and other compounds such as Zn of IIB group and Al of IIIB group does not carbonize cellulose even if heated above the critical temperature of water (375 ° C). , A yellowish brown color of aldehyde odor was obtained, and a reaction accompanied by gas evolution was observed at the same time. The component of this gas is mainly C
In addition to O ₂ , H ₂ and CO, they were various hydrocarbons such as ethylene, propylene and butenes. The main reactions are the formation of formaldehyde and the following decomposition reactions. HCHO → CO + H ₂ This result is important as a method for producing flammable gas from the carbohydrates contained in the present invention, but the amount of saturated hydrocarbon is very small, and in this respect, the composition of flammable natural gas generally found is It was different. Among the metal compounds that were effective as catalysts in this experiment, Ca and Mg are the main components of seawater. Therefore, although studies were conducted to include other components of seawater, the use of NaCl alone is harmless but not particularly effective for the method of the present invention. As a result of examining SO ₄ ²⁻ which is another main component, a special effect was observed when it was used as a counter ion of the above metals. CaSO as an example
Fry the cellulose suspension with ₄ when heated. In this case, the cellulose was oxidized, the generated gas contained a large amount of CO ₂ , and the hydrocarbons such as CH ₄ and C ₂ H ₆ were small. Next, looking at the reaction between CaSO ₃ and the suspension of cellulose, a large amount of hydrocarbons was produced.

The gas generated in these two reactions is a water-soluble gas which is considered to be a mixture of hydrocarbons such as CO ₂ , CO, H ₂ and CH ₄ and aldehydes. Further, the used sulfate and the like are reduced to finally become CaS, and the production of hydrocarbon gas is terminated. Looking at the reaction between CaS and the suspension of cellulose, although the gasification of cellulose occurred, the amount of hydrocarbons in the gas was extremely small. CaS
The S in the compounds of the O ₄ or the like, CH ₄ generation has been performed while the CaSO ₄ and CaSO ₃ is reduced to CaS Looking relationship of the degree of oxidation and CH ₄ production amount, CaS
O ₄ , CaSO _3, etc., appear to be non-catalytic as they change during CH ₄ formation. However, although the oxygen of these compounds is ultimately used for the oxidation of cellulose, CH
It is considered that the catalyst functions as a CH ₄ generation catalyst by physically maintaining the distance between Ca and S during the generation of ₄ . The mechanism of hydrocarbon generation in this reaction is not trivial, but it is presumed that it is basically due to the formation of aldehydes and the redox disproportionation reaction as shown in the following equation. HCHO + HCHO → CH ₄ + CO ₂ RCHO + HCHO → RCH ₃ + CO ₂ (R: aldehyde residue)

In the petroleum produced by the interposition of seawater, a plant called a raw material first adsorbs seawater components, dissolves in seawater and permeates underground. SO ₄ ²⁻ in seawater is reduced to SO ₃ ^{2− in an} underground reducing environment. This is due to reduction by bacteria or oxidation of iron and the like. When the underground thermal environment is reached, the carbohydrates in the plant are M
HSO is converted to aldehyde type monosaccharides by hydrolysis using gSO ₃ , CaSO _3, etc. as catalysts and rocks as carriers.
CO ₂ and hydrocarbons are produced by the elimination and disproportionation reaction of CHO. Then, both of them move to the low temperature part in the upper part of the formation, and CO ₂ is basically dissolved in water or absorbed by basic salts. In addition, since ions of metals such as Ca ²⁺ and Mg ²⁺ are stoichiometrically excessive in seawater as compared with SO ₄ ²⁻ , a part of CO ₂ generated here is insoluble carbonic acid. It becomes salt and is fixed. Excess CO ₂ behaves with hydrocarbons. In addition, hydrocarbons have low solubility in water and small specific gravity, so they migrate to the ground if there is no cap rock on the upper part. As described above, carbohydrate mainly produces lower hydrocarbons, that is, CH ₄ , C ₂ H _{6 and the} like. Polysaccharides such as hemicellulose existing in plants also react similarly to cellulose, although at a considerably low temperature. Organic compounds containing more carbon than carbohydrates, such as lignin, which exists together with cellulose in plants, have a low gasification rate and are considered to be mainly higher hydrocarbons.

The characteristic feature of the carbohydrate decomposition reaction of the present invention is that it produces water-soluble gas, which is considered to be aldehydes and their derivatives. In the method of the present invention, in a reaction in which a metal salt of sulfur oxide is not used as a catalyst, the aldehyde is decomposed and H ₂
And a large amount of CO are produced, and the reaction using a metal salt of a sulfur oxide as a catalyst is characterized by producing a large amount of hydrocarbons which are considered to be a disproportionation reaction of an aldehyde, as described above. However, H ₂ and CO are also generated in the latter reaction, which seems to be due to the fact that the heating rate is too fast in the experimental method. In addition, the formation of hydrocarbons with double bonds, which are not contained in conventional flammable natural gas, is observed, which seems to be due to other types of carriers in the heating rate. In the method of the present invention, when kaolin, which is a clay mineral active in the isomerization and decomposition reaction of hydrocarbons, is used as a carrier, it is observed that the production of hydrocarbons having a double bond such as ethylene is suppressed. ..

The carbohydrate used in the present invention is a compound of carbon and water, which is classified as Cm (H ₂ O) n.
Examples thereof include a group of substances having a molecular formula of [m and n are integers] and their derivatives, and include saccharides such as monosaccharides, disaccharides and polysaccharides, and mixtures thereof. In addition, the starting materials used in the present invention naturally include all substances including carbohydrates. For example, wood, herbs, grains, seaweeds, phytoplankton and processed products and derivatives thereof, that is, pulp, various papers, natural fibers such as cotton and hemp, artificial fibers and films such as rayon and acetate, millet, grains. Starch, potato starch, etc. (hereinafter simply referred to as carbohydrate).

The heating temperature in the method of the present invention is usually 20.
It is carried out in the range of 0 to 400 ° C. For example, 200 when using sucrose as a starting material and a CaSO ₃ catalyst.
A flammable gas was sufficiently obtained at around ℃. Further, when the experiment was carried out using a CaSO ₃ catalyst using potato starch as a starting material, it decomposed from around 250 ° C. and a flammable gas was obtained.
Cellulose, which is widely used as a structural polysaccharide in the plant kingdom, is the most resistant to decomposition among carbohydrates. Therefore, in this case, it is necessary to keep the temperature of the reaction system above the critical point of water at about 375 ° C. Therefore, as is clear from the examples of the present invention described later, 370 to 380 ° C. is necessary, but 400
Heating above ℃ is meaningless. Regarding the produced gas, it is sufficient to cool the reaction vessel and collect the combustible gas after confirming the completion of the reaction after the pressure rise stops after heating, but if the gas is extracted at a high temperature, the total amount of gas produced in the reaction is Be done. In the case of glycerin and CaSO ₃ , for example, flammable gas was obtained at 300 ° C. or higher in addition to acrolein. This is due to the oxidation of glycerin to produce the monosaccharide triose,
This is gasification.

Examples of the catalyst used in the present invention include oxides, hydroxides, carbonates of metals such as Group IIA Mg, Ca, Sr, Ba, Group IIB Zn, and Group IIIB Al in the Periodic Table of Elements. Examples thereof include sulfates, sulfites, sulfides and mixtures thereof. The catalyst used in the present invention is the metal hydroxide obtained by adding an alkali metal hydroxide to an aqueous solution of a compound other than the hydroxide among the general compounds of the metal in the periodic table of elements. The catalyst used in the present invention is an aqueous solution or suspension of a compound other than the sulfate and sulfite among the general compounds of the above metals in the Periodic Table of Elements, to which an alkali metal sulfate or sulfite is added. The catalyst used in the present invention is a catalyst obtained by adding an alkali metal hydroxide to the metal hydroxide in the Periodic Table of the Elements, if necessary, and absorbing H ₂ S. These are sulfides of the above metals or mixtures of these with alkali metal sulfides. Similarly, a substance that has absorbed SO ₂ can be a sulfite salt of the above metal or a sulfur lower oxide salt of SOx (x = 1 to 2). In addition, a carbon dioxide of the above metal can be formed by absorbing CO ₂ . The sulfides of these metals, the salts of lower sulfur oxides, the carbonates, and mixtures of these with the same salts of alkali metals are all effective as catalysts for use in the present invention.

In the practice of the present invention, a carbohydrate and a catalyst are dissolved or suspended in water or brine and heated. The amount of the catalyst used is 5 wt% or more with respect to the carbohydrate, and the amount of water is large with respect to the monosaccharide and the polysaccharide. Although different, it is usually used in an amount of 3 to 2000 times.
Hydrogen ion concentration index in this reaction system: pH is 6 or more, and preferably 7 to 10 is basic. The pH of the catalyst and brine used is adjusted with reagents as necessary. The term "brown water" as used herein includes seawater, oil and gas field drainage water, and general inorganic salt aqueous solutions. Since seawater contains the catalyst necessary for carrying out the present invention, carbohydrates and, if necessary, a carrier are added for use. Other brackish water or the like is used after adding a catalyst, a carbohydrate and, if necessary, a carrier necessary for carrying out the present invention.

As the carrier carrying the catalyst used in the present invention, the decomposition reaction proceeds even if it is not particularly used, but in this case, the gas generation amount may decrease due to carbonization of the carbohydrate. The carrier of the catalyst used in the present invention,
Rocks and minerals generally found in the strata are effective. Especially when a salt of a sulfur compound is used as a catalyst for the production of hydrocarbons, iron, manganese, which inhibits its catalytic action,
It is not preferable to use a so-called colored mineral containing chromium or the like as a carrier. The carrier for the catalyst used in the present invention is silica, alumina, kaolin or a mixture thereof which is generally used in chemical reactions. Also, alumina, Al
Both (OH) ₃ can be used as catalyst or carrier in the process of the invention. Examples will be shown below, but the present invention is not limited to these examples.

[0016]

Example 1 In a 500 ml autoclave, 350 ml of water
10 g of Al (OH) ₃ was charged as a catalyst into a suspension in which 8.45 g of cellulose was well mixed and stirred and heated. The heating rate was 2 to 2.3 ° C / min. Reaction temperature, 370-3
After the reaction was completed at 80 ° C., the entire amount of the internal gas was released at a high temperature, and the gas was collected by cooling it to room temperature. The initial amount of gas obtained here was 1400 ml. This gas was washed with diluted alkaline water to remove water-soluble gases such as CO ₂ and other aldehydes. The amount of gas after cleaning was 540 ml, and the gas composition was as follows. Unit: vol
%. _{H 2: 39.3, CO: 46.4} , CH 4: 2.2, _{Ethylene: 3.8, C 2 H 6:} 0.4, propylene: 4.4, C ₃ H
₈ : 0.0, C ₄ H ₁₀ type: 0.4, butenes: 2.8, C ₅ or more: 0.2

[0017]

Example 2 The same procedure as in Example 1 was carried out using a suspension of 300 ml of 3% NaCl water and 8.45 g of cellulose, using 10 g of CaCO ₃ as a catalyst. Initial gas volume is 1
The amount of gas after washing was 402 ml, and the amount of gas after washing was 502 ml, and the gas composition was as follows. Unit: vol%. _{H 2: 40.7, CO: 46.1} , CH 4: 1.0, _{Ethylene: 1.3, C 2 H 6:} 4.1, propylene: 1.6, C ₃ H
₈ : 0.0, C ₄ H ₁₀ type: 0.9, butene type: 3.0, C ₅ or more: 1.2

[0018]

Example 3 Using an aqueous solution of 300 ml of water and 20 g of sucrose and 10 g of Ca (OH) ₂ as a catalyst, a reaction temperature of 220
Example was carried out at the same temperature as in Example 1. The initial amount of gas is 56
0 ml, the amount of gas after washing was 110 ml, and the gas composition was as follows. Unit: vol%. _{H 2: 17.0, CO: 75.7} , CH 4: 1.9, _{Ethylene: 0.4, C 2 H 6:} 0.2, propylene: 3.5, C ₃ H
₈ : 0.0, C ₄ H ₁₀ type: 0.2, butene type: 0.8, C ₅ or more: 0.3

[0019]

Example 4 Example 4 was repeated except that 350 g of water and 8.45 g of cellulose were mixed with 1 g of Mg (OH) ₂ as a catalyst and 10 g of kaolin as a carrier.
Initial gas volume is 1455 ml, gas volume after cleaning is 410 ml
And the gas composition was as follows: Unit: vo
l%. H ₂ : 1 2.6, CO: 28.3, CH ₄ : 7.8, ethylene: 0.0, C ₂ H ₆ : 27.3, propylene: 0.0, C ₃
H ₈ : 13.4, C ₄ H ₁₀ type: 3.2, butene type: 7.4, C
₅ or more: 0.0

[0020]

Example 5 The procedure of Example 1 was repeated, except that a suspension of 350 ml of water and 8.45 g of cellulose used ₂ g of Ca (OH) ₂ as a catalyst and 10 g of kaolin as a carrier.
Initial gas volume is 1555 ml, gas volume after cleaning is 475 ml
And the gas composition was as follows: Unit: vo
l%. _{H 2: 32.7, CO: 48.1} , CH 4: 2.0, _{Ethylene: 1.4, C 2 H 6:} 0.5, propylene: 6.7, C ₃ H
₈ : 0.0, C ₄ H ₁₀ type: 0.9, butene type: 6.6, C ₅ or more: 1.0

[0021]

Example 6 In a suspension of 400 ml of water and 4.44 g of cellulose, 4.2 g of Mg (OH) ₂ as a catalyst and Na ₂ S were used.
O ₃ 1 / 2H ₂ O 4.4 g, Al (OH) ₃ 1 as carrier
The same procedure as in Example 1 was carried out except that 0 g was used. The initial amount of gas is 830 ml, the amount of gas after cleaning is 260 ml,
The gas composition was as follows. Unit: vol%. _{H 2: 4.1, CO: 4.3} , CH 4: 69.9, ethylene:
0.7, C ₂ H ₆ : 14.1, propylene: 5.7, C
₃ H ₈ : 0.0, C ₄ H ₁₀ class: 0.1, butenes: 0.9, C
₅ or more: 0.1

[0022]

Example 7: A suspension of 400 ml of water and 4.32 g of cellulose, 4.2 g of Mg (OH) ₂ as a catalyst, and Na ₂ S.
The same procedure as in Example 1 was carried out except that 4.4 g of O ₃ 1 / 2H ₂ O and 10 g of kaolin were used as the carrier. The initial gas amount was 1230 ml and the gas amount after cleaning was 420 ml, and the gas composition was as follows. Unit: vol%. _{H 2: 8.7, CO: 11.4} , CH 4: 60.3, _{ethylene: 2.1, C 2 H 6:} 11.1, propylene: 5.1, C ₃
H ₈ : 0.1, C ₄ H ₁₀ type: 0.1, butene type: 1.1, C ₅
Above: 0.1

[0023]

Example 8 A suspension of 400 ml of water and 4.25 g of cellulose, 7 g of CaSO ₃ as a catalyst, and Al (OH)
_{3 The same} procedure as in Example 1 was carried out except that 7.8 g and silica 6 g as a carrier were used. The initial gas amount was 1420 ml and the gas amount after cleaning was 320 ml, and the gas composition was as follows. Unit: vol%. _{H 2: 4.6, CO: 6.0} , CH 4: 72.0, ethylene:
0.0, C ₂ H ₆ : 11.0, propylene: 4.1, C
₃ H ₈ : 0.0, C ₄ H ₁₀ type: 0.3, butene type: 2.0, C
₅ or more: 0.1

[0024]

Example 9 A suspension of 400 ml of water and 4.16 g of cellulose, 6.5 g of BaS as a catalyst and 1 silica as a carrier.
The same procedure as in Example 1 was carried out except that 0 g was used. The initial gas amount was 1000 ml and the gas amount after cleaning was 420 ml, and the gas composition was as follows. Unit: vol
%. _{H 2: 40.5, CO: 51.2} , CH 4: 0.4, _{Ethylene: 0.5, C 2 H 6:} 0.1, propylene: 4.0, C ₃ H
₈ : 0.0, C ₄ H ₁₀ type: 0.4, butene type: 2.7, C ₅ or more: 0.2

[0025]

Example 10 In a suspension of 400 ml of water and 4.08 g of cellulose, 4 g of ZnO and Na ₂ SO ₃ 1/2 H ₂ as a catalyst were used.
The same procedure as in Example 1 was carried out except that 4.4 g of O and 10 g of silica were used as the carrier. The initial gas amount was 660 ml and the gas amount after cleaning was 150 ml, and the gas composition was as follows. Unit: vol%. _{H 2: 10.5, CO: 8.7} , CH 4: 41.7, _{ethylene: 2.8, C 2 H 6:} 15.4, propylene: 0.0, C ₃
H ₈ : 10.7, C ₄ H ₁₀ type: 1.5, butene type: 6.0, C
₅ or more: 2.7

[0026]

According to the present invention, CO ₂ and H ₂ a carbohydrate as a raw material, CO, combustible gas mixtures, such as hydrocarbons can be easily obtained, by removing by known means of CO ₂ as needed It becomes a fuel or chemical raw material and is extremely useful in industry.

Front page continuation (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location B01J 23/02 M 8017-4G 27/04 M 6750-4G 27/053 M 6750-4G 27/055 M 6750- 4G 27/232 M 6750-4G C10L 3/06 // C01B 3/32 Z 9041-4G

Claims (4)

[Claims] 1. A method for decomposing a carbohydrate into a flammable gas, which comprises heating the carbohydrate with a catalyst and water or brine to 200 ° C. or higher. 2. A carbohydrate is a compound of carbon and water in an organic compound, which is a compound having a molecular formula of Cm (H ₂ O) n [m, n is an integer], or a derivative thereof or a substance containing the same. 13. A method of decomposing carbohydrates of claim 1 into combustible gases. 3. The catalyst is M of IIA group in the periodic table of the elements.
g, Ca, Sr, Ba, Zn of the IIB group, Al of the IIIB group or the like, and oxides, hydroxides, carbonates, sulfates, sulfites, sulfides of one or more kinds. 1 or 2
A method of decomposing the carbohydrates of the product into flammable gas. 4. The method for decomposing the carbohydrate according to claim 1, wherein the pH of the reaction system is 6 or more into a flammable gas.