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1. WO2009009976 - CATALYST COMBINATION AND PROCESS FOR DIRECT LIQUEFACTION OF CARBONACEOUS MATERIALS BY USING THE SAME

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[ EN ]

Catalyst combination and process for direct liquefaction
of carbonaceous materials by using the same

CROSS REFERENCE
The present invention claims the priority benefit of Chinese Patent Application No.200710201127.X, which has a filling date of July 19, 2007 and is entirely incorporated herein by reference.
FIELD OF INVENTION
The present invention relates to a catalyst combination and a process for direct liquefaction of carbonaceous materials by using the same, in particular, to a catalyst combination comprising an iodine-containing substance and a sulfur oxide species, and a process for direct liquefaction of a carbonaceous material by using the catalyst combination.
BACKGROUND OF THE INVENTION
The prospect that the world petroleum reserves will be depleted within the next several decades has caused the price of oil to escalate. Coal is a raw material of great importance and an abundant natural source. Thus, the coal liquefaction for production of liquid fuels and chemicals might become economically competitive.
Heretofore, a large number of catalysts have been identified as useful in processes for direct liquefaction of carbonaceous materials. For example, metal sulfides and oxides and mixtures thereof have been particularly useful as catalysts in such processes.
It has also been proposed to use iodine to enhance the hydroconversion of carbonaceous materials such as coal in thermal operations. For example, Maa et al disclosed in United States Patent 4824558 that iodine is added directly as iodine, hydrogen iodine or as a precursor which decomposes to yield either iodine or hydrogen iodide, and the hydroconversion using iodine was accomplished in the presence of hydrogen.
Haenel, et al., in Angew. Chem. Int. Ed., Vol. 45 (2006), had developed a method of converting high-rank bituminous coals by preceding hydrogenation with homogeneous borane or iodine catalyst. It shown that iodoboranes and iodine can be used as homogeneous catalysts to hydrogenate high-rank bituminous coals, including anthracite, resulting in a strong increase of the aliphatic at the expense of the aromatic structures of these coals. However, the product obtained by stirring a suspension of a bituminous coal in solvent together with catalysts was still a solid.
So far, most of existing processes for direct liquefaction of coal utilize molecular hydrogen at high pressure, so that the considerable expense of hydrogen production is one of the significant limitations for commercial application of these coal liquefaction processes. Sundaram, et al disclosed in U.S. Pat. No.4,687,570 that methane was directly used in coal liquefaction, but they did not use any catalyst in coal liquefaction.
Thus, there are still demands of novel catalyst systems and processes for direct liquefaction of carbonaceous materials such as coal.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a catalyst combination for direct liquefaction of carbonaceous materials, in which the catalyst combination comprises:
a) An iodine-containing substance, and
b) A sulfur oxide species.
In another aspect, the present invention provides a method of using a catalyst combination for direct liquefaction of carbonaceous materials, in which the catalyst combination comprises:
a) An iodine-containing substance, and
b) A sulfur oxide species.
In further another aspect, the present invention provides a process for liquefaction of carbonaceous materials, comprising heating the carbonaceous materials in a solvent in the presence of an iodine-containing substance and a sulfur oxide species at a temperature ranging from 2500C to 7500C under a pressure in the range of 0.1 MPa to 12MPa of a gas containing a hydrogen-donor, in which at least a part of the iodine-containing substance and a part of the sulfur oxide species are provided by a catalyst combination comprising:
a) An iodine-containing substance, and
b) A sulfur oxide species.
DETAILED DESCRIPTION OF THE INVENTION
The term "catalyst combination" used herein, in suitable conditions, may also be replaced by "catalyst system" or "catalyst composition", and means a combination comprising two or more components which exhibit catalytic activity when they are used together in direct liquefaction of a carbonaceous material. In some cases, at least one of the components may be in its original form, and if any, the residual component(s) may form one or more solutions and/or mixtures such as suspensions. In some other cases, all components may form a solution or a mixture.

The term "liquefaction of carbonaceous material" used herein means a process in which a carbonaceous material is treated with suitable substances, such as a hydrogen-donor and a catalyst combination in accordance with the present invention, under suitable conditions to convert at least a part of the carbonaceous material into liquid and/or gaseous products.
In certain embodiments of the catalyst combination, the iodine-containing substance is any suitable iodine-containing substance, such as iodine element, iodine oxide, iodic acid anhydride, ammonium iodide, alkaline metal iodides, alkaline earth metal iodides, ammonium iodate, alkaline metal iodates, alkaline earth metal iodates, boron iodide, organic iodine-containing compounds, and mixtures thereof, wherein the alkaline metal can be lithium, sodium, potassium, rubidium, or cesium, and the alkaline earth metal can be beryllium, magnesium, calcium, strontium, or barium, and wherein the organic iodine-containing compounds may be hydrocarbonyl iodide such as iodobenzene, iodomethane, iodoethane. In some cases, the iodine-containing substance is in the form of particles having an average diameter of 1 ~1000μm, preferably 10~500μm, more preferably 50~250μm, most preferably 70-1 OOμm.
In some embodiments of the catalyst combination, the sulfur oxide species is any suitable sulfur oxide species such as sulfur trioxide, sulfur dioxide, oleum, concentrated sulfuric acid, and mixtures thereof. In some cases, the concentration of sulfur trioxide in oleum is 20%~60%, and the sulfur trioxide is in the form of gas or solid.
In some embodiments, the catalyst combination can be, for example, a combination selected from potassium iodide/oleum, potassium iodide/sulfur trioxide, sodium iodide/oleum, sodium iodide/sulfur trioxide, iodic anhydride/oleum, iodic anhydride/sulfur trixoide, iodine/oleum, and iodine/sulfur trioxide.
In certain embodiments of the present invention, the catalyst combination may further comprise a suitable solvent. In some cases, the iodine-containing substance and/or the sulfur oxide species may be mixed with the solvent to form one or more solutions and/or mixtures such as suspensions, slurries or powders before they are used as a catalyst in a process for liquefaction of carbonaceous materials. In some other cases, at least one of the iodine-containing substance, the sulfur oxide species and the solvent may be mixed with others only when they are used as a catalyst in a process for liquefaction of carbonaceous materials. Examples of such solvent may be a hydroaromatic solvent. Some specific examples of the solvent include tetralin, tetrahydroquinoline, piperidine, indoline, perhydropyrene, pyrolidine, as well as hydrogenated anthracene oil, hydrogenated coal liquids, catalytic cracking residual oil, heavy hydrocarbon residues, and mixtures thereof.
In certain embodiments of the present invention, the catalyst combination may further comprise a carbonaceous material. In some cases, the iodine-containing substance and/or the sulfur oxide species and/or optionally the solvent may be mixed with the carbonaceous material to form one or more solutions and/or mixtures such as suspensions, slurries or powders before they are used in a process for liquefaction of carbonaceous materials. In some other cases, at least one of the iodine-containing substance, the sulfur oxide species, the solvent and the carbonaceous material may be mixed with others only when they are used in a process for liquefaction of carbonaceous materials. The carbonaceous material can be any suitable carbonaceous material that needs to be liquefied or contains at least a portion to be liquefied, such as coal including bituminous coal, brown coal, hard coal, sub-bituminous coal, anthracite coal, peat and lignite, oil shale, petroleum, tar sands, oil shale, and man-made residual oils, tars and heavy hydrocarbon residues, and mixtures thereof. In some cases, the carbonaceous material may be in the form of particles having an average diameter of 1 ~1000μm, preferably 10~500μm, more preferably 50~250μm, most preferably 70-1 OOμm. In some cases, the moisture of carbonaceous material is less than 10%, preferably 5%, more preferably 2%.
In certain embodiments of the present invention, if appropriate, two or more or all components of the catalyst combination may form a solution or a mixture such as suspension, slurry or powder, while other components, if any, may be in their original forms individually or form other mixtures and/or solutions. In some cases, each of mixtures or solutions or components in the catalyst combination may be kept individually during manufacture, transportation and/or storage, for example, they may be packaged in different containers individually or in different chambers of one or more containers. This may be advantageous under some situations to avoid, if any, for example, undesired interactions between components before they are used a catalyst combination, or to facilitate the manufacture, transportation and/or storage of such catalyst combination. In some embodiments, all components may be in their original forms individually and kept individually during manufacture, transportation and/or storage. However, in any above case, all components of the catalyst combination are considered as a whole and are used together at the same time or in any suitable order in a process for liquefaction of carbonaceous materials. In some embodiments, the catalyst combination is a solution or a mixture, which comprises an iodine-containing substance and a sulfur oxide species. In some other cases, when two or more of the components in the combination are mixed together, they may have, if appropriate, a physical or chemical interaction between each other.
In the present invention, the ratio of components in the catalyst combination may be determined according to actual conditions and requirements. In some embodiments, the weight ratio of iodine-containing substance : sulfur oxide species is 0.2-10 : 1 -20, preferably 1 -5 : 5-15. In the case that the catalyst combination comprises a solvent and/or a carbonaceous material, the weight ratio of iodine-containing substance : sulfur oxide species : solvent : carbonaceous material is 0.2-10 : 1 -20 : 0-1000 : 0-100, preferably 1 -5 : 5-15 : 0-200 : 0-50, more preferably 1 -2 : 6-10 : 0-150 : 0-50.
In some embodiments of the present invention, the iodine-containing substance and/or sulfur oxide species used in the process for liquefaction of carbonaceous materials may be partially or totally provided by a catalyst combination as described hereinabove. For example, in some embodiments, the process may use only the catalyst combination in accordance with the present invention to provide the needed iodine-containing substance and sulfur oxide species, while in other embodiments, the process may use the catalyst combination described herein to provide a portion of iodine-containing substance and a portion of sulfur oxide species. Similarly, the carbonaceous materials and the solvent used in the process may be partially or totally provided by the catalyst combination in accordance with the present invention as well. In some embodiments, besides those contained in the catalyst combination as described herein, the process may further use additional same or different iodine-containing substance, sulfur oxide species, solvent and/or carbonaceous material as described hereinabove.
In some embodiments of the present invention, the carbonaceous materials to be liquefied in the process of the present invention may be any suitable carbonaceous materials that needs to be liquefied or contains at least a portion to be liquefied, and examples of the carbonaceous materials may include coal such as bituminous coal, brown coal, hard coal, sub-bituminous coal, anthracite coal, peat and lignite, oil shale, petroleum, tar sands, oil shale, man-made residual oils, tars, heavy hydrocarbon residues, and mixtures thereof.
In some embodiments of the present invention, the solvent used in the process may serve as a liquid vehicle and/or a hydrogen donor. Examples of such solvent may comprise hydroaromatic solvents, such as tetralin, tetrahydroquinoline, piperidine, indoline, perhydropyrene, pyrolidine, as well as hydrogenated anthracene oil, hydrogenated coal liquids, catalytic cracking residual oil, heavy hydrocarbon residues, and mixtures thereof.
In some embodiments of the process, the hydrogen-donor may be a hydrogen-containing compound or a mixture comprising such compound, and the examples of hydrogen-donor may include natural gas, coal-bed gas, methane, ethane, coal oven gas, hydrogen gas, or a mixture thereof. In some cases, the gas may further comprise hydrogen gas and/or an inert gas such as noble gas and nitrogen gas. In some embodiments, natural gas, coal-bed gas and/or coal oven gas is used directly, or at 50-100% by volume of methane in a mix consisting of methane and hydrogen in a ratio of 99:1 - 1 :99. In another embodiment, natural gas or methane is solely used as the hydrogen-donor.

In the process of the present invention, the components of iodine-containing substance, sulfur oxide species, solvent and carbonaceous material may be added in a reactor simultaneously or in sequence by any order.
In the present invention, the ratio of components used in process may be determined according to actual conditions and requirements. In some embodiments, the weight ratio of iodine-containing substance : sulfur oxide species : solvent : carbonaceous material in the process is 0.2-10 : 1-20 : 50-1000 : 10-100, preferably 1 -5 : 5-15 : 70-200 : 100, more preferably 1 -2 : 6-10 : 100-150 : 100.
In some embodiments, the process is conducted at a temperature in the range of 250~750°C, preferably 280~480°C, more preferably 300~420°C, and at a pressure in the range of 1 -120MPa, preferably 5-20MPa, more preferably 7-12MPa, wherein the partial pressure of hydrogen-donor is in the range of 1 -12MPa, preferably, 2-10MPa, more preferably, 3-5MPa.
In some embodiments, the process is conducted for a time period in the range of 0.5-12 hours, preferably 0.5-8 hours, more preferably 0.5-6 hours, most preferably 1 -4 hours.
In some embodiments of the present invention, without limitation of any theory, it is believed that the iodine-containing substance may serve as a primary catalyst, the sulfur oxide species may serve as a co-catalyst, and the solvent may serve as both a vehicle as well as a reactant such as a hydrogen-donor, and the presence of the hydrogen donor solvent together with the hydrogen donor gas such as methane may increase the yield of desired liquid and gaseous hydrocarbons during the liquefaction of carbonaceous materials.
In some embodiments of the present invention, the iodine-containing substance, sulfur oxide species, solvent and/or carbonaceous material may be used in the form of a solid-liquid or liquid-liquid reaction mixture and fed into a reaction vessel and pressurized to elevated pressure. In some cases, the reaction mixture may be preheated up to 1000C, preferably to 80-900C, before introducing it into a reaction vessel. When the contents of the reaction vessel are heated to the reaction temperature, the reaction occurs between the carbonaceous, solvent and hydrogen-donor gas such as methane. This results in the formation of new and useful liquid products and gaseous products.
In some embodiments of the present invention, the process may further comprise steps of separating desired liquid and gaseous products from a reaction mixture after liquefaction, and the examples of such steps may comprise centrifugation, distillation, vaporization, filtration, extraction and so on. In some cases, at least a part of the residue of the separation steps may be further processed and/or recycled (or directly recycled) to replace at least partial or total iodine-containing substance, sulfur oxide species, solvent and/or carbonaceous material used in the process for liquefaction of carbonaceous materials. In some other cases, the liquid and gaseous products obtained by the separation may also be further processed to obtain a solvent and/or hydrogen-donor gas which can be used in the next turn of process for liquefaction of carbonaceous materials.
EXAMPLES
Although the present invention is described in terms of specific materials and process steps, it will be clear to one skilled in the art that various changes and modifications may be made in accordance with the invention described in the accompanying claims.
The following examples are presented merely by way of illustration and are not intended to limit the present invention beyond that defined in the accompanying claims.
In the following examples, Neimeng lignite, Shanxi bituminous coal are ground to a diameter of less than 0.1 mm, classified as <160mesh (about 100 micrometers) and <200mesh (about 75 micrometers) respectively, dried under vacuum at 1000C for 24hrs, and used as feedstock. The results of elemental analyses of these raw coals are summarized in Table 1.
Table 1. Elemental analyses of raw coals
Neimeng lignite Shanxi bituminous
coal coal
Elemental analysis, %, dmmf
C 61.1 77.86
H 2.79 4.32
S(total) 1.60 1.31
O(by difference) 8.06 8.16
H/C 0.55 0.67
Proximate analysis, %
Moisture, as received 5.94 2.47
Fixed carbon, dry 53.72 64.76
Volatile matter, dry 20.50 27.67
Calorific value, KJ/kg 23590 31480

In the following examples, the solid and liquid reaction products are analyzed by solvent fractionation using a series of extraction solvents, and the amount of gaseous products are determined by weighing the gases in the reactor before and after the gaseous products are released from the reactor.

The liquid products are fractionated by using a series of solvents into a hexane-soluble fraction (HXs); a tetrahydrofuran(THF)-soluble, hexane-insoluble fraction (THFs); and a THF-insoluble fraction which is also defined as an insoluble organic matter (IOM) that is moisture and ash free (maf). The amount of each of the fractions, except for the HXs, is determined by weighing the fraction after the solvent is evaporated off. The HXs is determined by a different way so that all losses, including those due to the escape of volatiles, are counted in this fraction. Thus, the conversion refers to a weight conversion of carbonaceous material, and is calculated by using the following equation.

convers 1- - J IOM
ion x 100
> maf

Wherein %com/eraoπ represents the weight convention of the carbonaceous material; gioM represents the weight of THF-insoluble organic matter after the reaction, which is calculated by the following equation: g!OM = (the weight of the THF-insoluble fraction after the reaction) - (the weight of moisture and ash in the original carbon carbonaceous material); and gmaf represents the weight of the moisture and ash free carbonaceous material, which is calculated by the equation: gmaf = (the weight of the original carbonaceous material) - (the weight of moisture and ash in the original carbon carbonaceous material).

The HS yield refers to a weight yield of the n-hexane-soluble liquid and gaseous products, and is calculated by using the following equation.
HS yield (wt%) = [(the weight of the original carbon carbonaceous material) + (the weight loss of the hydrogen-donor) - (the weight of the n-hexane-insoluble fraction)]/(the weight of the original carbon carbonaceous material)

Example 1
About 150 grams of tetralin as solvent were added to 75 grams of particulate Neimeng lignite coal having a particle size of less than 100 micros to form a suspension A. About 0.35 gram of potassium iodide, Kl, and 10 grams of 20% oleum were mixed with the suspension A, which was then loaded in an autoclave with a capacity of 1000-ml for direct liquefaction.
The air of the autoclave was firstly replaced by nitrogen for three times, and then gaseous methane (cold pressure of 5.0MPa) was introduced into the autoclave. The autoclave was then sealed and heated to 3000C for 1 h under an autogenous pressure (10MPa) with vigorous stirring (400rpm).
After the end of reaction, the gaseous, liquid and solid products of coal liquefaction were recovered from the autoclave by washing out with tetrahydrofuran (THF). After THF was removed by evaporation at 800C under vacuum for 12 hours, the resultant residue was extracted with n-hexane by Soxhlet Extraction for 24 hours and dried at a temperature of 800C under vacuum for 12 hours to obtain an n-hexane insoluble fraction, then the n-hexane insoluble fraction was further extracted with THF by Soxhlet extraction for 24 hours and dried at a temperature of 800C under vacuum for 24 hours to obtain a THF-insoluble fraction. The conversion and HS yield were calculated in accordance with the above equations and the results were shown in Table 2.
Example 2
About 75 grams of hydrogenated anthracene oil as solvent were added to 75 grams of particulate Neimeng lignite coal having a particle size of less than 74 micrometers to form a suspension B. About 3.75 grams of sodium iodide, NaI, and 15 grams of 40% oleum were mixed with suspension B, and then the mixture was loaded in an autoclave with a capacity of 1000-ml for direct liquefaction.
The air of the autoclave was firstly replaced by nitrogen gas for three times, and then gaseous methane (cold pressure of 2.0MPa) was introduced into the autoclave. The autoclave was then sealed and heated to 38O0C for 4 h under autogenous pressure (about 7MPa) with vigorous stirring (400rpm).

After the end of reaction, the gaseous, liquid and solid products of coal liquefaction were treated as in Example 1. The results of Example 2 are shown in Table 2.
Example 3
About 300 grams of catalytic cracking residual oil as solvent were added to 75 grams of particulate Shanxi bituminous coal having a particle size of less than 100 micrometers to form a suspension C. About 0.15 grams of boron triiodide, Bl3, and 3.75 grams of 60% oleum were mixed with suspension C, and then the mixture are subjected to direct liquefaction in an autoclave with capacity of 1000-ml.
The air of the autoclave was firstly replaced by nitrogen gas for three times, and then gaseous methane (cold pressure of 4.0MPa) was introduced to the autoclave. The autoclave was then sealed and heated to 42O0C for 3 h under autogenous pressure (9 MPa) with vigorous stirring (400rpm).
After the reaction, the gaseous, liquid and solid products of coal liquefaction were treated as in Example 1. The results of Example 3 are shown in Table 2.
Example 4
About 500 grams of tetralin as solvent were added to 75 grams of particulate Shanxi bituminous coal having a particle size of less than 74 micrometers to form a suspension D. About 7.5 grams of potassium iodate, KIO3 and 11.25 grams of 50% oleum were mixed with suspension D, and then the mixture was subjected to direct liquefaction in an autoclave of 1000-ml capacity.
The air of the autoclave was firstly replaced by nitrogen gas for three times, and then gaseous natural gas (cold pressure of 10 MPa) was introduced to the autoclave. The autoclave was then sealed and heated to 28O0C for 2 h under autogenous pressure (12 MPa) with vigorous stirring (400rpm).
After the reaction, the gaseous, liquid and solid products of coal liquefaction were treated as in Example 1. The results of Example 4 are shown in Table 2.
Example 5
About 250 grams of a heavy hydrocarbon residue as solvent were added to 75 grams of particulate Neimeng lignite coal having a particle size of about 75-100 micrometers to form a suspension E, in which the heavy hydrocarbon residue was distilled from the liquid product of Example 1 and had a boiling point range of about 350-4000C. About 0.75 grams of sodium iodate, NaIO3, and 0.75 grams of solid sulfur trioxide were mixed with suspension E, and then the mixture was subjected to direct liquefaction in an autoclave of 1000-ml capacity.
The air of the autoclave was firstly replaced by nitrogen gas for three times, and then gaseous methane (cold pressure of 3.0 MPa) was introduced to the autoclave. The autoclave was then heated to 33O0C for 0.5 h under autogenous pressure (7.5 MPa) with vigorous stirring (400rpm).
After the reaction, the gaseous, liquid and solid products of coal liquefaction were treated as in Example 1. The results of Example 5 are shown in table 2.
Example 6
The procedure of Example 1 was followed, except 0.1 gram of iodine and 0.25 gram of diiodine pentoxide instead of 0.35 gram of potassium iodide were used in Example 6.
After the reaction, the gaseous, liquid and solid products of coal liquefaction were treated as in Example 1. The results of Example 6 are shown in Table 2.
Table 2. Results of Examples 1 -6
Particle Conversion HS yield
Run Coal
size (μm) (wt%) (wt%)
Example 1 Lignite "™<Ϊ00 "™47J39
Example 2 Lignite <75 54.6 37.14
Example 3 Bituminous <100 55.95 37.19 Example 4 Bituminous <75 56.33 37.74
Example 5 Lignite <100 57.5 45.53
Example 6 lignite <100 53.3 40.26

Comparative Examples 1 -5
The comparative examples 1-5 were conducted respectively under the same conditions of Examples 1-5, except that no catalyst and co-catalyst was used in the comparative examples 1 -5. The results of the comparative examples 1 -5 are shown in Table 3.
Table 3. Results of Comparative Examples 1-5
Particle Conversion HS yield

Run Coal
size (μm) (wt%) (wt%)

Comparative Example 1 Lignite <100 32.49 25.13

Comparative Example 2 Lignite <75 35.5 30.05

Comparative Example 3 Bituminous <100 37.87 29.2

Comparative Example 4 Bituminous <75 33.33 28.95

Comparative Example 5 Lignite <100 34.85 32.23

It can be seen from the above examples and comparative examples that the catalyst combination in accordance with the present invention exhibited significant effects in direct liquefaction of carbonaceous materials. For example, when the catalyst combination of the present invention was used, the conversion and HS yield increased significantly. It was also indicated that the direct liquefaction of carbonaceous materials by using the catalyst of the present invention could be implemented by using only methane as hydrogen-donor, rather than by using a hydrogen product such as hydrogen gas or a hydrogen-containing gas.
By reading the present invention, those skilled in the art would understand that the present invention is not intended to be limited by what is disclosed in the examples, and any modifications and variants without departing from the general concept of the present invention fall within the scope of the present invention.