AU2005202194A1 - Methods of producing catalysts for synthesizing alcohols from water gas using palygorskite - Google Patents

Description

rn TITLE OF THE INVENTION CN Methods of producing catalysts for synthesizing alcohols from water gas using t palygorskite FIELD OF THE INVENTION The objective of this invention is to provide techniques of producing catalysts for synthesizing alcohols from water gas. The invention is particularly concerned with catalysts using the naturally occurring mineral palygorskite, also known as attapulgite, as the carrier, O with fine metal particles of Cu incorporating at least one of the following elements: V, Cr, Mn, Fe, Co and Zn adsorbed on the surfaces and within the crystal channels of palygorskite.

BACKGROUND OF THE INVENTION With the improvement of living standards and the progress of industrialization, energy demands have increased rapidly. These are especially pronounced in the demand for liquid fuels. However, because of the instability of the oil market, liquid fossil fuels are not always readily available or are available at high cost. An alternative and abundant resource is coal, which can be converted firstly to water gas and then to alcohols which can be used as alternative fuels.

Copper-containing catalysts are commonly used for the hydrogenation process, especially in the hydrogenation reactions of CO and CO 2 Both CO and CO2 are the main components of water gas. Under certain conditions, Cu-containing catalysts can assist the hydrogenation reaction in water gas and produce alcohols. Therefore, it is possible to convert coal into liquid fuels through an intermediate stage of water gas. This will enable the increasing usage of low grade coal and also ease the pressure of liquid fuel shortages.

There are many inventions for the synthesizing of alcohols using hydrogenation catalysts.

Apart from liquid and self-supported types of catalysts, most of those catalysts consist of oxides such as A1 2 0 3 or CeO 2 or Cr203, or MgO, or SiO 2 or TiO 2 or ZrO 2 or RE 2 0 3 or Cu-spinel (CuAl204), Cu-chromite (CuCr 2 0 4 etc. as the supports or the carriers. They can be found in the following inventions; Canadian patent Nos. CA2176311, CA1269401 and CA1236819, British Patent Nos. GB51488, GB2110557, GB2025418 and GB1364096, Chinese patent Nos. CN1390640 and CN1068976, European patent Nos. EP0864360, EP0156691, EP0146165 and EP0034338, German patent No. DE4238640, Japanese patent Nos. JP2002263497, JP2001205089, JP55106543, JP10277392, JP10080635, JP9267041, JP4364141, JP4363141, JP4122444 and JP4124152, Korean patent No. KR244661, Russian patent Nos. RU2218988 and RU2175886, US patent Nos. US2005080148, US6114279, US6054497, US5385949, US4666945, US4631266, US4436833, US4107089 and US3971735 etc. Those catalysts usually suffer from uneven distribution of Cu particles on /tt the carrier surfaces or have limited reactive surfaces or the costs of manufacturing the carrier Smaterials are high. It is desirable to find a cheap, stable material with a large specific area as CN the carrier. Certain minerals match these requirements and are suitable for the purpose.

There are only two inventions, e.g. German patent No. DE4238640 and US patent No.

US5045520 that utilize the mineral zeolite as carriers.

CPalygorskite, also known as attapulgite, is a naturally occurring clay mineral. In its natural state, it may take a variety of macroscopic forms from massive to papyraceous to fibrous. However it is fibrous on a microscopic scale, being of 0.5-5ptm in length and 030-100nm in diameter. Parallel channels are found in its crystal structure. These channels have approximate cross-sections of 0.5 x 0.5nm which gives palygorskite very large O specific surface areas and potential for adsorbing various atoms, radicals and molecules. Thus A palygorskite is a very favourable candidate for using as a carrier material for catalysts.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The objective of this invention is to provide techniques of producing catalysts for synthesizing alcohols from water gas.

Palygorskite, also known as attapulgite, is a naturally occurring clay mineral with a typical chemical formula of (Mg,Al) 2 Si 4 0 1 o(OH)-4H20. In its natural state, it may take a variety of macroscopic forms from massive to papyraceous to fibrous. It is fibrous on a microscopic scale, of 0.5-5plm in length and 30-100nm in diameter. It is a typical one-dimensional nano-sized natural mineral. The crystal structure of palygorskite contains continuous planes of tetrahedron layers of Si-O with Mg-O(OH) octahedron layers located between them. They form a basis of the structure. These basic units are arranged alternately and form parallel tunnels. These parallel tunnels have a cross-section of 0.37 x 0.64nm which gives palygorskite a very large specific surface area and potential for adsorbing various atoms, radicals and molecules and thus it is a very favourable candidate for using as the carrier for catalysts.

The core processes for this invention are firstly to physically purify the natural palygorskite by removing all the impurities at the Mg 2 site at the centre of the octahedrons and replacing them with H through the selective dissolution process; secondly the catalytic element of Cu incorporating at least one of the promoting elements of V, Cr, Mn, Fe, Co and Zn will be ion-exchanged with H' in the structure. Thirdly, these ion-exchanged cations will be converted into oxides after calcination and finally the metal oxide will be reduced to metallic elements in a reduction atmosphere. These metallic elements will be evenly distributed and tightly bound on the surfaces and within the crystal channels of palygorskite.

Catalysts produced by this process have the following advantages: palygorskite is a naturally occurring abundant mineral which is cheaper than the synthetic carriers; the physical characteristics of the carrier, i.e. palygorskite, and the distribution of catalytic element and promoting elements make the produced catalysts superior to the other catalysts tf with oxides as carriers in both catalytic activity and durability.

(1 Details of these processes are described as follows: Palygorskite is pulverized down to 300 mesh and then washed with mineral acids. The mineral acids can be either hydrochloric acid, or nitric acid, or sulphuric acid or CC3 combination of them. With regard to the environmental and economic concerns, hydrochloric acid is the preferred acid. Some of the mineral impurities associated with palygorskite, such as carbonates, certain clay minerals, oxides of iron family elements etc. can be dissolved and removed by the acid. The dissolution of those mineral Simpurities, especially the carbonates, will cause loss of the aggregation of other minerals Sin the samples and allow them to be easily separated. During the actual process, I concentrations and the amount of acids used are adjusted according to the amount of Scarbonates in the samples. The more carbonates contained, the larger amount or more ,1 concentrated the acids should be. During the acid treatment, cations located at the centre of octahedrons in the crystal lattices of palygorskite can be preferentially dissolved. Their positions will be replaced by In order to speed up the acid dissolution process, the reaction can be carried out at elevated temperatures, e.g.

90C. After the acid treatment, the samples should be washed with clean water several times to remove any remaining acid.

2. The second stage of processes is ion-exchange of the purified palygorskite with a Cu salts solution and a multi-element salts solution containing at least one of the following elements: V, Cr, Mn, Fe, Co and Zn. Once palygorskite has been mixed with those solutions, cations from the solution will replace those positions at the centre of octahedrons which were occupied by H Different types of anions in the solutions have little effect on the results of this ion-exchange process. Therefore, the type of ferric salts used is not critical, they can be chosen according to their availability and prices. After the ion-exchange process, the samples will be treated with NaOH or solution so the excessive cations in the solution can precipitate out as hydroxides.

The solid phase will be filtered and then washed with water several times to remove sodium or ammonium salts produced during the process.

3. The cleaned filter cake of palygorskite is then mixed with a suitable amount of water and then spray-dried. The spray-dried product contains loosely bound small palygorskite spheres. There is no conglomeration among palygorskite fibers and thus the characteristic surface activities of nano-particles are still maintained which will have advantageous catalytic properties.

4. The spray-dried palygorskite spheres are heated in a N 2 stream at 400. 500°C to remove all the H 2 0 molecules. After they have been completely dried, 3" 10% of H 2 will be mixed into the N 2 stream and those cations which are adsorbed on the surfaces and within the channels of palygorskite will be reduced into metal particles. The palygorskite spheres will be cooled to room temperature in the N 2 stream. The final 3) product will be stored in a sealed container under the protection of pure, dried N 2

(N

EXAMPLES

Examples of the process of this invention in the laboratory are described as follows: rn CI1 EXAMPLE 1: 1. 10Kg of palygorskite was firstly pulverized to <300mesh and mixed well with 30Kg of concentration of added nitric acid. The slurry was occasionally stirred during the O reaction. After 30hr, water from the slurry was removed by filtration. The solid was r washed with clean water then followed by filtrations. These were repeated 5 times to 0 remove all the remaining acid.

2. The cleaned filter cake was mixed well with 30Kg of 4mol of Cu(NO 3 2 0.5mol of Fe(N0 3 3 0.5mol of Co(N0 3 2 and 0.5mol of VOSO 4 solution. The slurry was occasionally stirred during the reaction. After 40hr, 0.5mol of NaOH solution was gradually added into the slurry until the pH of the slurry reached to 3. Water was removed from the slurry by centrifuging. The filter cake was washed with clean water then followed by filtrations. This cleaning process was repeated 5 times.

4. The filter cake was collected, mixed with water and spray dried.

The spray-dried powder was dried in a N 2 stream at 500 0 C for 2hr then 10% of H 2 was mixed into the N2 stream and heated for another 2hr.

6. The product was cooled to room temperature under the protection of N 2 and stored in an airtight container.

EXAMPLE 2: 1. 10Kg of palygorskite was firstly pulverized to <300mesh and mixed well with 80Kg of 3mol concentration of added hydrochloric acid. The slurry was occasionally stirred during the reaction. After 50hr, water from the slurry was removed by filtration. The solid was washed with clean water then followed by filtrations. These were repeated 3 times to remove all the remaining acid.

2. The cleaned filter cake was mixed well with 50Kg of 2mol of CuCl 2 Imol of FeCl 3 of ZnCl 2 and 0.5mol of CrCl 3 solution. The slurry was occasionally stirred during the reaction. After 40hr, 5mol of NH4OH solution was gradually added into the slurry until the pH of the slurry reached to 3. Water was removed from the slurry by centrifuging. The filter cake was washed with clean water then followed by filtrations. This cleaning process was repeated 5 times.

4. The filter cake was collected, mixed with water and spray dried.

The spray-dried powder was dried in a N 2 stream at 400 0 C for 4hr then 3% of H 2 was mixed into the N 2 stream and heated for another 6. The product was cooled to room temperature under the protection of N 2 and stored in an airtight container.

EXAMPLE 3: 1. 10Kg of palygorskite was firstly pulverized to <300mesh and mixed well with 50Kg of 3mol concentration of added sulphuric acid. The slurry was occasionally stirred during the reaction. After 40hr, water from the slurry was removed by filtration. The solid C was washed with clean water then followed by filtrations. These were repeated 5 times to remove all the remaining acid.

2. The cleaned filter cake was mixed well with 50Kg of 2mol of CuSO 4 Imol of CoSO 4 of MnSO 4 and 0.5mol of FeSO 4 solution. The slurry was occasionally stirred Sduring the reaction. After 60hr, Imol of NH40H solution was gradually added into the O slurry until the pH of the slurry reached to lr 3. Water was removed from the slurry by centrifuging. The filter cake was washed with 0 clean water then followed by filtrations. This cleaning process was repeated 5 times.

4. The filter cake was collected, mixed with water and spray dried.

The spray-dried powder was dried in a N 2 stream at 450 0 C for 3hr then 3% of H 2 was mixed into the N 2 stream and heated for another 6. The product was cooled to room temperature under the protection of N 2 and stored in an airtight container.

EXAMPLE 4: 1. 10Kg of palygorskite was firstly pulverized to <300mesh and mixed well with 80Kg of 3mol concentration of added hydrochloric acid. The slurry was occasionally stirred during the reaction. After 50hr, water from the slurry was removed by filtration. The solid was washed with clean water then followed by filtrations. These were repeated times to remove all the remaining acid.

2. The cleaned filter cake was mixed well with 30Kg of 4mol of CuSO 4 Imol of Co(N0 3 2 Cr(N0 3 3 and 0.5mol Zn(NO 3 2 solution. The slurry was occasionally stirred during the reaction. After 60hr, 5mol of NH 4 0H solution was gradually added into the slurry until the pH of the slurry reached to 3. Water was removed from the slurry by centrifuging. The filter cake was washed with clean water then followed by filtrations. This cleaning process was repeated 5 times.

4. The filter cake was collected, mixed with water and spray dried.

The spray-dried powder was dried in a N 2 stream at 500 0 C for 2hr then 10% of H 2 was mixed into the N 2 stream and heated for another 2hr.

6. The product was cooled to room terrerature under the protection of N 2 and stored in an airtight container.

Claims (1)

1. 5-20% and the weights of other elements are 5-10% that of catalyst. dcomplexed CLAIM 2: Methods of producing catalysts for synthesizing alcohols from water gas using palygorskite, also known as attapulgite, as the carrier with fine metal particles of Cu incorporating at least one of the following elements, V, Cr, Mn, Fe, Co and Zn adsorbed on the surfaces and within the crystal channels of palygorskite as claimed in CLAIM 1, where palygorskite is a naturally occurring clay mineral with typical chemical formula of (Mg,Al) 2 Si 4 010o4H 2 0, it can be in the form of either clays, or lumps, or mudstone, or shale. CLAIM 3: Methods of producing catalysts for synthesizing alcohols from water gas using palygorskite, also known as attapulgite, as the carrier with fine metal particles of Cu incorporating at least one of the following elements, V, Cr, Mn, Fe, Co and Zn adsorbed on the surfaces and within the crystal channels of palygorskite as claimed in CLAIM 1, the procedures are to pulverize the naturally occurring palygorskite down to 300 mesh and then wash with mineral acids which are 3-8 times of their weights, react for 30-50hr with occasional stirring then de-water by filtration or centrifuging and wash several times with water to remove any acid residues, the filter cake is mixed with 3-5 times by weight of Cu salts solution and the multi-element salts solution containing at least one of the following elements, V, Cr, Mn, Fe, Co and Zn for 40-60hr with occasional stirring, then NaOH or NH 4 0H solution at 0.5-5mol in concentration is slowly added until the pH value of the slurry reaches to 6.0, the solid phase is collected by filtration or centrifuging and then washed several times with water, the cleaned filter cake is spray-dried and the spray-dried powder is further dried in a N 2 stream at 400-500C for 2-4hr then is heated in a N 2 stream with 3-10% of H2 mixed for 2-5hr, the final product is cooled to room temperature under the protection of N 2 atmosphere. CLAIM 4: Methods of producing catalysts for synthesizing alcohols from water gas using palygorskite, also known as attapulgite, as the carrier with fine metal particles of Cu incorporating at least one of the following elements, V, Cr, Mn, Fe, Co and Zn adsorbed on the surfaces and within the crystal channels of palygorskite as claimed in CLAIM 3, where the mineral acids can be either hydrochloric acid, or nitric acid, or sulphuric acid or their combination at 3-5mol in concentration. CLAIM Methods of producing catalysts for synthesizing alcohols from water gas using palygorskite, also known as attapulgite, as the carrier with fine metal particles of Cu incorporating at least one of the following elements, V, Cr, Mn, Fe, Co and Zn adsorbed on the surfaces and within the crystal channels of palygorskite as claimed in CLAIM 3, where the Cu salts solution contains 1-4mol of Cu and the multi-element salts solution contains 1-2mol of either V, or Cr, or Mn, or Fe, or Co, or Zn, or a combination of them. CLAIM 6: Methods of producing catalysts for synthesizing alcohols from water gas using palygorskite, also known as attapulgite, as the carrier with fine metal particles of Cu incorporating at least one of the following elements, V, Cr, Mn, Fe, Co and Zn adsorbed on the surfaces and within the crystal channels of palygorskite as claimed in CLAIMS 3 and where the Cu salts are either chloride, or sulphate, or nitrate, or their hydrates or a combination of them. CLAIM 7: Methods of producing catalysts for synthesizing alcohols from water gas using palygorskite, also known as attapulgite, as the carrier with fine metal particles of Cu incorporating at least one of the following elements, V, Cr, Mn, Fe, Co and Zn adsorbed on the surfaces and within the crystal channels of palygorskite as claimed in CLAIMS 3 and where the multi-elements salts are either chlorides, or sulphates, or nitrates, or their hydrates or a combination of them. Names of Applicants Ying Ye Jun Li Daidai Wu Wei-Jit'Chang Dated: 2 3 r d of May, 2005