JP5679088B2 - Method for reducing the molecular weight of organic substances - Google Patents

Description

  The present invention relates to a method for modifying an organic substance to reduce its molecular weight in order to convert the organic substance such as waste plastic into gaseous fuel or liquid fuel.

At present, most of waste plastic, oil-impregnated sludge, waste oil, etc. are incinerated. However, incineration treatment has a high environmental load such as CO ₂ generation, and there is a problem of thermal damage of the incinerator, and establishment of chemical recycling technology is required.
Among chemical recycling technologies, technologies for converting organic substances into gaseous fuels and liquid fuels have been variously studied mainly with respect to waste plastics. For example, the following proposals have been made.

In Patent Document 1, a coke oven gas (COG) having a hydrogen concentration of 60 vol% or more, preferably 80 vol% or more and a temperature of 600 ° C or more is reacted with an organic material such as waste plastic, thereby hydrogenating the organic material with high efficiency. A method for increasing the heat of COG by decomposition and gasification is disclosed.
Further, Patent Document 2 discloses a method in which petroleum fluid contact catalyst (FCC) is used as a heat medium / catalyst and waste plastic is decomposed at a temperature of 350 to 500 ° C. to be converted into liquid fuel.
Further, in Patent Document 3, when pyrolyzing RDF, wood, etc., the gas generated by pyrolysis is steam reformed, and the gas having a high hydrogen concentration by this steam reforming is circulated to the pyrolysis section to generate hydrogen. A method of performing pyrolysis in a gas atmosphere with a high concentration is disclosed.

JP 2007-224206 A JP 2010-013657 A JP 2001-131560 A JP 2006-104339 A JP 2006-188574 A

However, the above prior art has the following problems.
First, regarding Patent Document 1, since the hydrogen concentration in COG is 60 vol% or more is limited to the end of the dry distillation in the coal dry distillation process, in the method of Patent Document 1, the gas flow path is opened at the end of the dry distillation. It is necessary to switch and supply COG of 600 ° C. or more containing a large amount of dust to a waste plastic hydrocracking reactor. However, it is difficult to stably operate the flow path switching valve for a long time under such a severe condition, and in this sense, it can be said that the technique is poor in feasibility. Furthermore, for efficient gasification of waste plastic, it is necessary to continuously supply COG containing 60 vol% or more of hydrogen to the hydrocracking reactor. In addition, it is necessary to install a hydrogen concentration meter and a flow path switching valve, which increases the equipment cost.

Moreover, although the method of patent document 2 advances catalytic cracking and aromatization by FCC catalyst addition, since it reacts by an inert gas flow, 13 mass% of heavy oil components and coke are produced | generated in total ( Example 1) is not a satisfactory level as a light fuel production technology.
Further, the gas generated by the method of Patent Document 3 is mainly H ₂ , CO, and CO ₂ , and the combustion heat is about 1800 kcal / Nm ³ that is slightly lower than that of the exhaust gas generated from the metallurgical furnace. The value is limited.

  Accordingly, an object of the present invention is to efficiently reform an organic substance using a gas that can be stably supplied when the organic substance such as waste plastic is reduced in molecular weight to be converted into gaseous fuel or liquid fuel. Provided is a method for reducing the molecular weight of an organic substance, which can be reduced in molecular weight, can be obtained with a modified product containing a small amount of heavy components and carbonaceous matter and a large amount of light components, and can be implemented with relatively simple equipment. There is.

As a result of repeated studies to solve the above problems, the present inventors have mixed (i) water vapor into an exhaust gas containing carbon dioxide and hydrogen generated in a gasification melting furnace, and this mixed gas has a high molecular weight. The organic substance is modified to reduce the molecular weight, or (ii) the shift reaction is performed by adding excess steam to the exhaust gas containing carbon monoxide and hydrogen generated in the gasification melting furnace. A high-molecular-weight organic substance is reformed with a mixed gas containing hydrogen after the reaction, that is, hydrogen contained in the exhaust gas, carbon dioxide and hydrogen produced by the shift reaction, and water vapor not consumed in the shift reaction. It has been found that reducing the molecular weight is effective. Further, in the methods (i) and (ii) above, it was found that there is a suitable range for the composition of the mixed gas for organic substance modification.

The present invention has been made on the basis of such findings and has the following gist.
[1] Mixing water vapor with the exhaust gas (g ₀ ) containing carbon dioxide and hydrogen generated in the gasification melting furnace, bringing the mixed gas (g) into contact with an organic substance, reforming the organic substance, and reducing the molecular weight A method for reducing the molecular weight of an organic substance characterized by comprising:
[2] in the exhaust gas (g ₁₎ containing carbon monoxide and hydrogen generated in the gasification and melting furnace with the addition of excess water vapor is possible to perform a shift reaction, hydrogen contained in the exhaust gas (g ₁₎ And a mixed gas (g) containing carbon dioxide and hydrogen produced by the shift reaction and water vapor not consumed in the shift reaction. The mixed gas (g) is brought into contact with the organic substance to reform the organic substance. And reducing the molecular weight of the organic substance.

[3] The method for reducing the molecular weight of an organic substance according to the above [2], wherein the CO concentration in the mixed gas (g) after the shift reaction is less than 10 vol%.
[4] A method for reducing the molecular weight of an organic substance, wherein the water vapor concentration of the mixed gas (g) is 5 to 70 vol% in any one of the above [1] to [3].
[5] In the method of [4] above, the mixed gas (g) is characterized in that the water vapor concentration is 20 to 70 vol%, the hydrogen concentration is 10 to 40 vol%, and the carbon dioxide concentration is 10 to 40 vol%. A method for reducing the molecular weight of a substance.
[6] The method according to any one of [1] to [5] above, wherein the organic substance to be modified is at least one selected from waste plastic, oil-containing sludge, waste oil, and biomass. A method for reducing the molecular weight of organic substances.
[7] The organic material reformate obtained by the method for reducing the molecular weight of the organic material according to any one of [1] to [6] is recovered, and the reformed material is used as a fuel and / or a reducing agent for a steel mill. A method of operating a steelworks characterized by:

According to the present invention, when a high molecular weight organic substance such as waste plastic is reduced in molecular weight to be converted into gaseous fuel or liquid fuel, the organic substance is efficiently reformed using a gas that can be stably supplied. Thus, it is possible to obtain a high-calorie modified product having a low molecular weight, a small amount of heavy components and carbonaceous components, and a large amount of light components. Also, with regard to the implementation equipment, there is no need for special measuring instruments or flow path switching valves, and the organic substance can be reformed even at a relatively low reaction temperature. it can.
In addition, since CO ₂ produced by the shift reaction changes to CO by the carbon dioxide reforming reaction during the reforming of the organic substance, chemical recycling of the organic substance can be performed without increasing the amount of CO ₂ generated. It becomes possible.

In the method for reducing the molecular weight of an organic substance according to the first invention of the present application, an exhaust gas (g ₀ ) containing carbon dioxide and hydrogen generated in a gasification melting furnace (hereinafter referred to as “gasification melting furnace generated exhaust gas”). Water vapor is mixed with the gas (g), and this mixed gas (g) is brought into contact with the organic substance to modify the organic substance to reduce the molecular weight.
Further, in the method for reducing the molecular weight of an organic substance according to the second invention of the present application, an exhaust gas (g ₁ ) containing carbon monoxide and hydrogen generated in a gasification melting furnace (hereinafter referred to as “gasification melting furnace generated exhaust gas”). In some cases, excess water vapor is added to cause the shift reaction to occur, so that hydrogen contained in the exhaust gas (g ₁ ), carbon dioxide and hydrogen generated by the shift reaction, and the shift reaction are consumed. The mixed gas (g) containing the water vapor that has not existed is brought into contact with the organic substance, and the organic substance is modified to reduce the molecular weight. Note that adding excess water vapor to the exhaust gas (g ₁ ) means adding water vapor so that excess water vapor that is not consumed in the shift reaction remains in the mixed gas (g).

Here, the gasification and melting furnace is a furnace facility that heats garbage in a low-oxygen state and pyrolyzes it, and burns or recovers the gas generated by this pyrolysis and melts ash and incombustibles at high temperatures. There are a method in which thermal decomposition and melting are performed integrally and a method in which they are performed separately. Specifically, a gasification reforming system (for example, a thermoselect system (see Patent Document 4 and Patent Document 5)), a shaft furnace system (for example, a coke bed system, an oxygen system, a plasma system, etc.), a kiln furnace System, fluidized bed system, semi-distillation and negative pressure combustion system. In the present invention, any type of gasification melting furnace generated exhaust gas may be used, or a mixture of two or more types of exhaust gas may be used. The exhaust gas generated in the gasification melting furnace may be an exhaust gas containing carbon dioxide and hydrogen, or carbon monoxide and hydrogen. As such an exhaust gas, an exhaust gas containing carbon dioxide and hydrogen having a carbon dioxide concentration of 20 to 60 vol% and a hydrogen concentration of 60 to 20 vol%, or a carbon monoxide concentration of 10 to 50 vol% and a hydrogen concentration of 50 Exhaust gas containing 10% by volume of carbon monoxide and hydrogen can be exemplified as exhaust gas applicable to the method of the present invention. In the case of an exhaust gas containing a carbon monoxide concentration and hydrogen, hydrogen is generated by a shift reaction. Therefore, even if the hydrogen concentration is 10 vol%, the composition is suitable as the mixed gas (g) of the present invention.
Even if the pyrolysis gas is a gas generated by partial combustion in the furnace or a gas generated by partial combustion outside the furnace, the gas recovered as pyrolysis gas without burning It may be.

  Generally, high molecular weight organic substances such as waste plastic are known to start thermal decomposition when heated at a temperature of 300 to 400 ° C. or higher, but at this time, they become lighter and heavier. Coexistence of hydrogen during thermal decomposition is effective in suppressing heavy formation and reducing the molecular weight because hydrogen addition reaction and hydrocracking reaction to hydrocarbon species proceed. However, the high temperature is required for hydrocracking, and the hydrogen consumption is a problem.

On the other hand, steam reforming and carbon dioxide reforming can be regarded as oxidation of hydrocarbons by oxygen in H ₂ O and CO ₂ molecules, achieving low molecular weight and suppressing carbonaceous production with a small amount of hydrogen addition. it can. Furthermore, steam reforming and carbon dioxide reforming are characterized in that the reaction temperature decreases as the carbon chain of the organic molecule to be modified becomes longer. In the method of the present invention, the low molecular weight of an organic substance is efficiently promoted even at a relatively low reaction temperature, the amount of hydrogen consumption is small, and the generation of heavy components and carbonaceous matter is hardly recognized. It is considered that the four reactions of hydrogenation, hydrocracking, steam reforming, and carbon dioxide reforming proceed simultaneously by reforming (reducing molecular weight) the organic substance using (g).
Incidentally, as the hydrogenation reaction, not only hydrogenation reaction to hydrocarbon species, that is gaseous products that also proceed hydrogenation reaction to CO and CO ₂ to produce a light hydrocarbon such as methane It is suggested from the analysis results. In the description of the present invention, for the sake of simplicity, the hydrogenation reaction to CO or CO ₂ is simply described as hydrogenation (or hydrogenation reaction) without being distinguished from the hydrogenation reaction to hydrocarbon species.
When the organic substance used in the present invention is represented by hydrocarbon (CmHn), the above reaction can be represented by the following reaction formula.
Hydrogenation: CmHn + H ₂ → CmH _{n + 2}
Hydrogenolysis: CmHn + H ₂ → CpHq + CrHs (m = p + r, n + 2 = q + s)
Steam reforming: CmHn + H ₂ O → Cm-1H _n-2 + CO + 2H ₂
Carbon dioxide reforming: CmHn + CO ₂ → Cm-1H _n-2 + 2CO + H ₂
However, the hydrogenation includes the following CO and CO ₂ methanation reactions.
CO + 3H ₂ → CH ₄ + H ₂ O, CO ₂ + 4H ₂ → CH ₄ + 2H ₂ O
The above hydrogenation and hydrocracking also proceed with H ₂ produced by steam reforming or carbon dioxide reforming.

Moreover, the exhaust gas generated from the gasification melting furnace contains carbon monoxide and hydrogen as described above, and excess water vapor is added to the exhaust gas (g ₁ ) containing carbon monoxide and hydrogen. If the following shift reaction (1) is performed, CO can be converted into H ₂ and CO _2, which is suitable as a mixed gas (g) for organic substance modification.
CO + H ₂ O → H ₂ + CO ₂ (1)
Gasification melting furnace-generated exhaust gas has various compositions. According to this method, a suitable mixed gas (g) can be obtained by controlling the shift reaction corresponding to the exhaust gas composition.
That is, by appropriately controlling the excess ratio of water vapor added excessively to the exhaust gas (g ₁ ) and the reaction rate of the shift reaction, each concentration of water vapor, hydrogen, and carbon dioxide gas in the gas is controlled, and the organic substance is modified. It can be a quality mixed gas (g).
The reaction rate of the shift reaction can be controlled by adjusting the residence time in the shift reactor. For example, in order to shorten the residence time, a method in which the shift reactor length is reduced or the catalyst charge amount is reduced is generally used. In this case, the shift reactor length and the catalyst charge amount are almost until equilibrium. What is necessary is just to set it as about 1 / 2-1 / 4 in the case of advancing reaction.

The exhaust gas generated from the thermoselect gasification melting furnace usually contains about ₂₀ to 40 vol% of CO, 40 to 20 vol% of CO2, and about ₂₀ to 40 vol% of H2. Thus, by simply mixing an appropriate amount of water vapor in the exhaust gas (g ₀₎ containing such carbon dioxide and _{hydrogen, CO: 15~20vol%, CO 2} : 35~10vol%, H 2: 15~20vol%, H ₂ O: The composition is about 20 to 50 vol%, and is suitable as a mixed gas (g) for organic substance modification.

Hereinafter, details and preferred conditions of the method of the present invention will be described.
In the first invention of the present application, the reason why the exhaust gas (g ₀ ) generated from the gasification melting furnace is used as the exhaust gas containing carbon dioxide and hydrogen is that it contains carbon dioxide and hydrogen at a relatively high concentration, This is because the nitrogen concentration is low. Furthermore, the exhaust gas generated from the gasification melting furnace has a relatively high hydrogen concentration even when the secondary combustion rate (CO2 / (CO + CO2) × 100) exceeds 50%. ₀ ).
As the gasification melting furnace generated exhaust gas (g ₀ ), any of the exhaust gases generated in various gasification melting furnaces as described above may be used, or a mixed gas of two or more kinds of exhaust gases may be used. .
In the method of the present invention, a mixed gas (g) for organic substance reforming can be obtained simply by mixing water vapor into the gasification melting furnace-generated exhaust gas (g ₀ ). The mixing method is not particularly limited, and may be mixed on the upstream side of the organic material reforming reactor, or may be mixed in the reforming reactor.

In the second invention of the present application, the reason why the exhaust gas (g ₁ ) generated from the gasification melting furnace is used as the exhaust gas for the shift reaction is that it contains carbon monoxide at a relatively high concentration and usually has a low nitrogen concentration. Because.
As the gasification melting furnace generated exhaust gas (g ₁ ), any of the exhaust gases generated in various gasification melting furnaces as described above may be used, or a mixed gas of two or more kinds of exhaust gases may be used. . An exhaust gas generated from a gasification reforming gasification melting furnace such as a thermoselect method is more preferable because it has a relatively high carbon monoxide concentration. Furthermore, the exhaust gas generated from the gasification melting furnace usually has a relatively stable exhaust gas composition, and the fact that the reforming reaction of the organic substance can be performed stably is also used as the exhaust gas (g ₁ ) of the present invention. That is why.

The exhaust gas (g ₁ ) to be shift-reacted has no problem in obtaining a mixed gas (g) for organic substance reforming if it has a composition as follows.
CO: 80-10 vol%
CO _2: 10~50vol%
H _2: 0 super ~30vol%
N _2: 0~30vol%
If the CO concentration exceeds 80 vol%, the amount of water vapor added to make the mixed gas (g) after the shift reaction have a suitable composition becomes very large, which is not economical. If it is less than 10 vol%, the CO concentration is low, so the shift reaction rate is slow, the reactor becomes large, and it is not economical. A more preferable CO concentration is 10 to 60 vol%, and 10 to 50 vol% is particularly preferable.
A CO ₂ concentration exceeding 50 vol% is not preferable because the CO ₂ concentration in the mixed gas (g) after the shift reaction becomes too high. Further, if it is less than 10 vol%, the CO ₂ concentration in the mixed gas (g) becomes too low, which is not preferable. A more preferable CO ₂ concentration is 10 to 40 vol%.
If the H ₂ concentration exceeds 30 vol%, the amount of steam added to make the mixed gas (g) after the shift reaction have a suitable composition becomes very large, which is not economical. A more preferable H ₂ concentration is 20 vol% or less.
It is preferable to control the CO concentration after the shift reaction to less than 10 vol%. If the CO concentration after the shift reaction exceeds 10 vol%, the efficiency of the organic substance modification in the subsequent process is lowered, which is not preferable. More preferably, it is controlled to be less than 5 vol%.

Here, nitrogen does not contribute at all to the chemical reaction (shift reaction, hydrogenation, hydrocracking, steam reforming, carbon dioxide reforming) occurring in the present invention, while diluting the gaseous fuel produced, Low combustion heat (hereinafter referred to as “LHV”) is reduced. In particular, when the nitrogen concentration exceeds 50 vol%, the LHV of the gaseous fuel is significantly reduced and the shift reaction rate tends to be reduced. Therefore, the nitrogen concentration is preferably within the above composition range.
The shift reaction in the method of the present invention may be carried out by a known method and is not particularly limited. In general, steam is added to the exhaust gas (g ₁ ) in advance, and this is introduced into a fixed bed reactor filled with a catalyst to perform a shift reaction. Alternatively, the water vapor to be added in advance may be partially used, the catalyst may be packed in multiple stages in the reactor, and the remaining water vapor may be added between the catalyst layer and the catalyst layer.

In the present invention (the first and second inventions of the present application), it is obtained by mixing water vapor with exhaust gas (g ₀ ), or obtained by adding water vapor to exhaust gas (g ₁ ) to cause shift reaction. The organic gas reforming mixed gas (g) contains water vapor, hydrogen and carbon dioxide. Although there is no special restriction | limiting in those density | concentrations, For the following reasons, it is preferable that water vapor | steam density | concentration is 5-70 vol%.
That is, when the water vapor concentration is low, the decomposition rate of organic substances such as waste plastics is low. However, by setting the water vapor concentration to 5 vol% or more, a certain level of organic material decomposition rate can be secured. As a result, the production rate of gas fuel (gasification rate) and the production rate of liquid fuel (liquefaction rate) can be kept at a constant level, and the production amount of heavy components can be reduced. On the other hand, when the water vapor concentration is high, CO ₂ tends to remain in the reforming reaction product gas of organic substances (gas generated by low molecular weight reforming of organic substances, the same shall apply hereinafter), and gas fuel / liquid fuel LHV tends to decrease. However, if the water vapor concentration is 70 vol% or less, it is possible to suppress the CO ₂ residue in the reforming reaction product gas, and it is also possible to suppress the decrease in the LHV of the gaseous fuel / liquid fuel.
Further, from the viewpoint of ensuring the decomposition rate of the organic substance, both the hydrogen concentration and the carbon dioxide concentration of the mixed gas (g) are preferably 5 vol% or more.

Moreover, for the following reasons, the more preferable composition of the mixed gas (g) for organic substance reforming is: water vapor concentration: 20 to 70 vol%, hydrogen concentration: 10 to 40 vol%, carbon dioxide concentration: 10 to 40 vol%. It is. In addition, it does not prevent that other gas components (for example, nitrogen etc.) are contained in this mixed gas (g). By setting the water vapor concentration to 20 vol% or more, the decomposition rate of the organic substance can be sufficiently increased, and the LHV of the gaseous fuel can be increased. The reason why the water vapor concentration is 70 vol% or less is as described above. By setting the hydrogen concentration to 10 vol% or more (more preferably 12 vol% or more), it is possible to suppress the CO ₂ from remaining in the gaseous fuel even when the organic substance is reformed at a relatively low temperature. Can do. By setting the carbon dioxide concentration to 10 vol% or more (more preferably 13 vol% or more), H ₂ that is a low-calorie gas component is less likely to remain in the gaseous fuel as compared to hydrocarbons and CO. Moreover, the decomposition rate of organic substances, such as a waste plastic, can be made into a preferable level by making hydrogen concentration and carbon dioxide concentration into 40 vol% or less. Moreover, from the above viewpoints, a more preferable gas composition of the mixed gas (g) is a water vapor concentration: 25 to 65 vol%, a hydrogen concentration: 15 to 35 vol%, and a carbon dioxide concentration: 15 to 35 vol%. In addition, it does not prevent that other gas components (for example, nitrogen etc.) are contained in this mixed gas (g).

  In addition, as one of the characteristics of the present invention, the ratio of the amount of gaseous fuel produced and the amount of liquid fuel produced in reforming the organic substance can be controlled by the water vapor concentration of the mixed gas (g) for reforming the organic substance. It is done. That is, when the water vapor concentration of the mixed gas (g) is 50 vol% or more, gaseous fuel is mainly produced (that is, gaseous fuel production amount> liquid fuel production amount), and when the water vapor concentration is 40 vol% or less, liquid fuel is mainly produced. (Ie, gaseous fuel production amount <liquid fuel production amount). In addition, since the influence of hydrogen concentration and carbon dioxide concentration is not as remarkable as the influence of water vapor concentration, it may be within the preferable range of the present invention.

Next, conditions for modifying (lowering the molecular weight) of the organic substance with the mixed gas (g) will be described.
In the present invention, there is no particular limitation on the organic material to be reduced in molecular weight by modification, but high molecular weight organic material is suitable, for example, waste plastic, oil-containing sludge, waste oil, biomass, etc. One or more of these can be targeted.

Although there is no special restriction | limiting in the kind of waste plastics made into object, For example, the object plastics etc. which are an industrial waste type | system | group and a container packaging recycling law can be mentioned. More specifically, polyolefins such as PE and PP, thermoplastic polyesters such as PA and PET, elastomers such as PS, thermosetting resins, synthetic rubbers, foamed polystyrene and the like can be mentioned. In addition, inorganic substances such as fillers are added to many plastics, but in the present invention, such inorganic substances are not involved in the reaction, and thus are discharged from the reforming (low molecular weight) reactor as solid residues. The In addition, the waste plastic is preliminarily cut to an appropriate size as required, and then charged into the reforming reactor.
Further, if the waste plastic contains a chlorine-containing resin such as polyvinyl chloride, chlorine is generated in the reforming reactor, and this chlorine may be contained in the gaseous fuel or liquid fuel. Therefore, when there is a possibility that the waste plastic contains a chlorine-containing resin, a chlorine absorbent such as CaO is introduced into the reforming reactor so that chlorine is not contained in the generated gaseous fuel or liquid fuel. It is preferable to make it.

  Oil-containing sludge is a sludge-like mixture generated in an oil-containing waste liquid treatment step, and generally contains about 30 to 70% by mass of water. Examples of the oil in the sludge include, but are not limited to, various mineral oils, natural and / or synthetic oils and fats, and various fatty acid esters. In addition, in order to improve handling properties such as when supplying oil-containing sludge to a reforming reactor (reactor for reforming organic substances to reduce the molecular weight, the same applies hereinafter), a method such as centrifugation is used. You may reduce the water | moisture content in sludge to about 30-50 mass%.

Examples of the waste oil include, but are not limited to, various used mineral oils, natural and / or synthetic fats and oils, and various fatty acid esters. Moreover, the mixture of these 2 or more types of waste oil may be sufficient. In addition, in the case of waste oil generated in the steel mill rolling process, it generally contains a large amount of water (usually more than about 80% by mass), but this water is also reduced in advance by a method such as specific gravity separation. It is advantageous in terms of handleability.
When the organic substance contains water, water vapor is generated in the reforming reactor. Therefore, the excess ratio of water vapor added in the shift reaction is determined in consideration of the amount.

  Examples of biomass include, but are not limited to, sewage sludge, paper, construction waste, thinned wood, and other processed biomass such as waste solid fuel (RDF). Since biomass usually contains a large amount of water, it is preferable to dry it beforehand in view of energy efficiency. In addition, in the case of biomass containing relatively high concentrations of alkali metals such as sodium and potassium, alkali metals may be deposited in the reforming reactor. It is preferable to keep it. In addition, large biomass such as construction waste is cut in advance and charged into the reforming reactor.

The reaction temperature during organic substance modification is preferably as follows according to the type of organic substance. In the case of waste plastic or biomass, a reaction temperature of about 400 to 900 ° C. is appropriate. When the reaction temperature is less than 400 ° C, the decomposition rate of waste plastics and biomass is low. In the case of oil-containing sludge or waste oil, the reaction temperature is suitably about 300 to 800 ° C. When the reaction temperature is less than 300 ° C., the decomposition rate of oil-containing sludge and waste oil becomes low. On the other hand, even if the reaction temperature exceeds 800 ° C., there is no effect on the reforming (lower molecular weight) characteristics of the oil-containing sludge or waste oil, but it is not economical because the temperature is higher than necessary.
Moreover, when the mixture which consists of waste plastics and / or biomass and oil-containing sludge and / or waste oil is made into object, about 400-800 degreeC is suitable for reaction temperature from the point mentioned above. In addition, the influence of reaction temperature with respect to the ratio of gaseous fuel production amount and liquid fuel production amount is hardly seen. In addition, since the influence of pressure is hardly observed, it is economical to operate the reforming reactor at normal pressure or at a slight pressure of about several kg / cm ² .

The type of the reforming reactor is not particularly limited, but organic substances such as waste plastic move smoothly in the reactor and can be efficiently contacted with the mixed gas (g) for organic substance reforming. A horizontal moving bed reactor such as a rotary kiln is preferred.
In the present invention, a catalyst is not particularly required for reforming the organic substance, but the reaction may be carried out by filling the catalyst. As the catalyst, one or more kinds of catalysts each having steam reforming activity, carbon dioxide reforming activity, hydrogenation activity, and hydrocracking activity can be used. Specific examples include Ni-based reforming catalysts, Ni-based hydrogenation catalysts, Pt / zeolite-based petroleum refining catalysts, and the like. Also, converter-generated dust, which is known to be composed of fine Fe particles, can be used as a reforming catalyst or a hydrocracking catalyst.

When the catalyst is packed, the contact between the organic material such as waste plastic and the catalyst is good, so a vertical reforming reactor is used instead of a horizontal moving bed reforming reactor such as a rotary kiln. May be adopted. In this case, it is preferable that the mixed gas (g) is supplied from the lower part and / or the side part rather than the upper part of the reforming reactor because the contact between the mixed gas (g) and the organic substance or catalyst is good.
As the vertical reforming reactor, a general fixed bed reactor or fluidized bed reactor used in the chemical industry can be used. In particular, a mixed gas (g) is supplied from the lower part of the reforming reactor. When the method is adopted, a blast furnace, a shaft furnace, or a converter, which is an iron manufacturing facility, can be used as a reforming reactor. When a blast furnace or shaft furnace is used as a reforming reactor, an organic substance and a catalyst are supplied continuously from the top of the furnace, and a mixed gas (g) is continuously supplied from the bottom of the furnace to counter-current contact, and gas is supplied from the top of the furnace. It is preferable that the product is a moving bed type in which the liquid product and the catalyst are continuously extracted from the lower part of the furnace because the reaction efficiency becomes high. When a converter is used as a reforming reactor, an organic substance and a catalyst are introduced into the furnace, then a mixed gas (g) is continuously supplied from the lower part of the furnace, and a gas product is continuously supplied from the upper part of the furnace. The liquid product and the catalyst can be extracted in a batch reaction system similar to steelmaking blowing, in which the furnace is tilted and extracted after a certain time of reaction.
In general, fluidized bed reactors are known to be excellent in heat conduction, but when fluidized bed reactors are employed in the present invention, the rate of molecular weight reduction of organic substances is low because of excellent heat conduction. There are advantages such as high, which is preferable.

The reformed organic substance obtained by the method of the present invention is usually a gas and a liquid, which are suitable as a gaseous fuel and a liquid fuel, and are used in ironworks such as a reducing agent for iron ore. It can also be used as an agent.
Combustible components of the gaseous fuel comprises a hydrocarbon of carbon monoxide and C1 -C4, the LHV of about 6~10Mcal / Nm ^3. Thus, although it is LHV comparable to natural gas, since carbon monoxide concentration is high, it is characterized by higher combustibility than natural gas. Because of its high carbon monoxide concentration and high combustibility, it is safer to use it as a city gas alternative fuel in factories with metallurgical furnaces such as steelworks than to supply it as household city gas. preferable.
Moreover, since the hydrocarbon content of carbon monoxide and C1 to C4 is high, it can be used as a reducing agent for blast furnaces and a coagulant for the sinter production process as an alternative to natural gas.

  Since liquid fuel is composed of C5 to C24 hydrocarbons, it is a mixture of naphtha (C5 to C8), kerosene (C9 to C12), and light oil (C13 to C24) and contains almost equivalent to heavy oil (C25 and above). There is no good quality light oil. This liquid fuel may be used separately as naphtha, kerosene, or light oil by distillation separation, but as a mixture, it is used as a fuel for factories with metallurgical furnaces such as ironworks, or as a heavy oil substitute reductant for blast furnaces. May be.

Oil obtained by removing hydrocarbons having a relatively high vapor pressure such as naphtha from liquid fuel can also be used as a reducing agent for a blast furnace as an alternative to heavy oil.
In addition, since the content of naphtha (C5 to C8) is large, in addition to use as a light liquid fuel, it can also be used as a chemical industry raw material after distilling and separating naphtha. For example, the naphtha fraction separated by distillation can be contact-modified and converted to benzene, toluene, xylene, or the like.
The reformed product of the organic substance obtained by the method of the present invention can be separated into gaseous fuel and liquid fuel by cooling the reforming reaction product gas and then performing gas-liquid separation. Further, naphtha, kerosene, and light oil can be separated from the liquid fuel by performing distillation separation as necessary. The cooling method, the gas-liquid separation method, and the distillation separation method of the reforming reaction product gas can be performed by known methods, and there is no particular limitation.

・ Invention Example 1
A branch pipe is provided in the discharge pipe for the exhaust gas (hereinafter referred to as "Purified synthesis gas") generated from the refined Thermoselect Waste Gasification and Reforming Process after removing impurities such as hydrogen chloride. A part of the thermogas can be extracted through this branch pipe. A gas cooler for cooling the reforming reaction product gas equipped with a flow control valve, a steam mixer, a gas preheater, a reforming reactor (externally heated rotary kiln), and a liquid fuel collector on the downstream side of the branch pipe Were arranged in this order. On the inlet side of the reforming reactor, a screw conveyor type waste plastic quantitative charging device was installed. In addition, a sampling port and a flow meter were installed in the gas outlet piping after cooling of the gas cooler.

The average composition of Samogasu _{is, H 2: 31vol%, CO} : 33vol%, CO 2: 30vol%, H 2 O: <1vol%, N 2: was 6 vol%. A steam gas of 108 Nm ³ / h and steam at a pressure of 10 kg / cm ² G as steam were supplied to the steam mixer at 64 Nm ³ / h, and the temperature was raised to 430 ° C. with a preheater. The gas composition after steam mixing was H ₂ : 20 vol%, CO: 21 vol%, CO ₂ : 19 vol%, H ₂ O: 37 vol%, and N ₂ : 4 vol%. This mixed gas for organic substance decomposition had a flow rate of 172 Nm ³ / h (mass flow rate of 171 kg / h).

The externally heated rotary kiln, which is a reforming reactor, is preheated to 500 ° C. in advance. The mixed gas is introduced into the reforming reactor, and 880 kg / kg of polyethylene that has been crushed into granules as a model material for waste plastics. Then, the temperature was raised to 800 ° C., which is the planned reaction temperature. After reaching 800 ° C., the liquid product collected in the liquid fuel collector was discharged, and then the reforming reaction of the waste plastic was continued for 1 hour.
The amount of gas fuel is determined from the gas analysis results after cooling by the gas cooler, and the amount of liquid fuel is determined from the analysis results of the liquid product collected in the liquid fuel collector. LHV was calculated | required about gaseous fuel. The results are shown in Table 1.

Since the total amount of thermogas, water vapor, and polyethylene supplied as raw materials was 1050 kg / h, the production rate relative to the total amount of the raw materials supplied was 32% for gas fuel and 60% for liquid fuel. Since it is difficult to directly measure the amount of unreacted polyethylene, the total yield of gaseous fuel (340 kg / h) and liquid fuel (630 kg / h) with respect to the total amount (1050 kg / h) of the supplied thermogas, water vapor, and polyethylene is When defined as the polyethylene decomposition rate, in this invention example 1, since the polyethylene decomposition rate is a sufficiently high value of 92% and the generation of hydrocarbons of C25 or higher is hardly observed, polyethylene is effectively a low molecular weight It is clear that H ₂ O, CO ₂ and H ₂ are completely consumed by the reforming reaction of the organic substance, and it is considered that four reactions of steam reforming, carbon dioxide reforming, hydrogenation, and hydrocracking proceeded simultaneously. . The LHV of the produced gaseous fuel was 8.1 Mcal / Nm ^3, which was increased to 4.5 times that of thermogas (1.8 Mcal / Nm ³ ).

-Invention Example 2
Water vapor was added to a thermogas having the same composition as that of Invention Example 1 to cause a shift reaction, and a test for reducing the molecular weight of an organic substance using a mixed gas obtained thereby was performed. Therefore, a shift reactor (cylindrical vertical type) filled with an Fe—Cr high temperature shift catalyst was installed downstream of the steam mixer, and the preheating temperature was changed to 320 ° C. Gas composition after shift reaction _{H 2: 28vol%, CO:} 4vol%, CO 2: 28vol%, H 2 O: 37vol%, N 2: was 3 vol%. This mixed gas for organic substance decomposition had a flow rate of 172 Nm ³ / h (164 kg / h in mass flow rate).

In the same manner as in Invention Example 1, a reforming reaction of granular polyethylene, which is a model material of waste plastic, was performed, and the amount and composition of the obtained gaseous fuel and liquid fuel were determined, and LHV was determined for the gaseous fuel. . The results are shown in Table 2.
According to this, the production rate with respect to the total amount of feedstock in the present invention example was 37% for gaseous fuel and 62% for liquid fuel, and the polyethylene degradation rate was 99%, which was almost completely reduced in molecular weight. The LHV of the produced gaseous fuel was 9.3 Mcal / Nm ³ , which was 5.2 times higher than that of the thermogas.
In Invention Example 2, since the CO concentration was previously reduced to less than 10% by shift reaction, the LHV of the gaseous fuel was higher and the polyethylene decomposition rate was higher than in Invention Example 1. This is presumably because the hydrogen and carbon dioxide concentrations contained in the mixed gas (g) were increased by the shift reaction in the example of the present invention, and the molecular weight of the organic substance was reduced very efficiently.

Claims (5)

By causing the exhaust gas (g ₁₎ in the addition of excess steam shift reaction containing carbon monoxide and hydrogen generated in the gasification and melting furnace, and hydrogen wherein contained in the exhaust gas (g _1), A mixed gas (g) containing carbon dioxide and hydrogen produced by the shift reaction and water vapor not consumed in the shift reaction is brought into contact with the organic substance, and the organic substance is reformed. Thus, when the molecular weight is reduced, the organic material is at least one selected from waste plastic, oil-containing sludge, waste oil, and biomass. The method for reducing the molecular weight of an organic substance according to claim 1, wherein the CO concentration of the mixed gas (g) after the shift reaction is less than 10 vol%.   The method for reducing the molecular weight of an organic substance according to claim 1 or 2, wherein the mixed gas (g) has a water vapor concentration of 5 to 70 vol%.   The mixed gas (g) has a water vapor concentration of 20 to 70 vol%, a hydrogen concentration of 10 to 40 vol%, and a carbon dioxide concentration of 10 to 40 vol%. Method.   The organic substance reformed product obtained by the method for reducing the molecular weight of an organic substance according to any one of claims 1 to 4 is recovered, and the reformed product is used as a fuel and / or a reducing agent for a steel mill. How to operate the steelworks.