US3909213A - Desulfurization of coal - Google Patents
Desulfurization of coal Download PDFInfo
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- US3909213A US3909213A US425189A US42518973A US3909213A US 3909213 A US3909213 A US 3909213A US 425189 A US425189 A US 425189A US 42518973 A US42518973 A US 42518973A US 3909213 A US3909213 A US 3909213A
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- United States
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- salt
- metal
- chloride
- coal
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- 239000003245 coal Substances 0.000 title claims abstract description 106
- 238000006477 desulfuration reaction Methods 0.000 title claims abstract description 13
- 230000023556 desulfurization Effects 0.000 title claims abstract description 13
- 229910001510 metal chloride Inorganic materials 0.000 claims abstract description 86
- 230000029087 digestion Effects 0.000 claims abstract description 64
- 150000003841 chloride salts Chemical class 0.000 claims abstract description 61
- 238000000034 method Methods 0.000 claims abstract description 60
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 58
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 57
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 52
- 239000011593 sulfur Substances 0.000 claims abstract description 52
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 52
- 239000000203 mixture Substances 0.000 claims abstract description 47
- 150000002894 organic compounds Chemical class 0.000 claims abstract description 25
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 21
- 238000007670 refining Methods 0.000 claims abstract description 12
- 238000002844 melting Methods 0.000 claims abstract description 8
- 230000008018 melting Effects 0.000 claims abstract description 8
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical group [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 claims description 59
- 150000003839 salts Chemical class 0.000 claims description 31
- 239000011592 zinc chloride Substances 0.000 claims description 29
- 235000005074 zinc chloride Nutrition 0.000 claims description 29
- 229910052976 metal sulfide Inorganic materials 0.000 claims description 27
- 239000000463 material Substances 0.000 claims description 25
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 20
- 239000000243 solution Substances 0.000 claims description 18
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical group [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims description 16
- 239000000292 calcium oxide Substances 0.000 claims description 16
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 16
- 229910021578 Iron(III) chloride Inorganic materials 0.000 claims description 9
- 150000001805 chlorine compounds Chemical class 0.000 claims description 8
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 claims description 8
- KKCBUQHMOMHUOY-UHFFFAOYSA-N sodium oxide Chemical compound [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 claims description 8
- 229910001948 sodium oxide Inorganic materials 0.000 claims description 8
- 238000001816 cooling Methods 0.000 claims description 7
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims description 6
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 claims description 6
- 239000011260 aqueous acid Substances 0.000 claims description 6
- 239000001110 calcium chloride Substances 0.000 claims description 6
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 6
- 229910000041 hydrogen chloride Inorganic materials 0.000 claims description 6
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 claims description 6
- 229910000037 hydrogen sulfide Inorganic materials 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 239000012768 molten material Substances 0.000 claims description 6
- 239000012266 salt solution Substances 0.000 claims description 5
- 238000001035 drying Methods 0.000 claims description 4
- 238000005453 pelletization Methods 0.000 claims description 4
- 150000003568 thioethers Chemical group 0.000 claims 2
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 9
- 238000000605 extraction Methods 0.000 description 8
- 239000011521 glass Substances 0.000 description 8
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 4
- 150000002898 organic sulfur compounds Chemical class 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 3
- 235000011941 Tilia x europaea Nutrition 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000004571 lime Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 238000004876 x-ray fluorescence Methods 0.000 description 3
- TXUICONDJPYNPY-UHFFFAOYSA-N (1,10,13-trimethyl-3-oxo-4,5,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-17-yl) heptanoate Chemical compound C1CC2CC(=O)C=C(C)C2(C)C2C1C1CCC(OC(=O)CCCCCC)C1(C)CC2 TXUICONDJPYNPY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910021380 Manganese Chloride Inorganic materials 0.000 description 2
- GLFNIEUTAYBVOC-UHFFFAOYSA-L Manganese chloride Chemical compound Cl[Mn]Cl GLFNIEUTAYBVOC-UHFFFAOYSA-L 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- AMQJEAYHLZJPGS-UHFFFAOYSA-N N-Pentanol Chemical compound CCCCCO AMQJEAYHLZJPGS-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 229910021626 Tin(II) chloride Inorganic materials 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 2
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 description 2
- 239000003830 anthracite Substances 0.000 description 2
- JHXKRIRFYBPWGE-UHFFFAOYSA-K bismuth chloride Chemical compound Cl[Bi](Cl)Cl JHXKRIRFYBPWGE-UHFFFAOYSA-K 0.000 description 2
- YKYOUMDCQGMQQO-UHFFFAOYSA-L cadmium dichloride Chemical compound Cl[Cd]Cl YKYOUMDCQGMQQO-UHFFFAOYSA-L 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 239000011565 manganese chloride Substances 0.000 description 2
- 235000002867 manganese chloride Nutrition 0.000 description 2
- 229940099607 manganese chloride Drugs 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- -1 sodium chloride-manganese chloride Chemical compound 0.000 description 2
- 239000001119 stannous chloride Substances 0.000 description 2
- 235000011150 stannous chloride Nutrition 0.000 description 2
- 150000004763 sulfides Chemical class 0.000 description 2
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 2
- 229910052815 sulfur oxide Inorganic materials 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 101100536354 Drosophila melanogaster tant gene Proteins 0.000 description 1
- 235000019687 Lamb Nutrition 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- DKGAVHZHDRPRBM-UHFFFAOYSA-N Tert-Butanol Chemical compound CC(C)(C)O DKGAVHZHDRPRBM-UHFFFAOYSA-N 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- KOPBYBDAPCDYFK-UHFFFAOYSA-N caesium oxide Chemical class [O-2].[Cs+].[Cs+] KOPBYBDAPCDYFK-UHFFFAOYSA-N 0.000 description 1
- 229910001942 caesium oxide Inorganic materials 0.000 description 1
- BSEHISUIPNKWKT-UHFFFAOYSA-L calcium;zinc;dichloride Chemical compound [Cl-].[Cl-].[Ca+2].[Zn+2] BSEHISUIPNKWKT-UHFFFAOYSA-L 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000010908 decantation Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000003077 lignite Substances 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 238000010310 metallurgical process Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 150000005324 oxide salts Chemical class 0.000 description 1
- CHWRSCGUEQEHOH-UHFFFAOYSA-N potassium oxide Chemical compound [O-2].[K+].[K+] CHWRSCGUEQEHOH-UHFFFAOYSA-N 0.000 description 1
- 229910001950 potassium oxide Inorganic materials 0.000 description 1
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 150000003464 sulfur compounds Chemical class 0.000 description 1
- IEKWPPTXWFKANS-UHFFFAOYSA-K trichlorocobalt Chemical compound Cl[Co](Cl)Cl IEKWPPTXWFKANS-UHFFFAOYSA-K 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L9/00—Treating solid fuels to improve their combustion
- C10L9/02—Treating solid fuels to improve their combustion by chemical means
Definitions
- ABSTRACT A process for desulfurization of coal which comprises: digesting, in a digestion zone, coal and a Group [A or 11A metal oxide or mixtures thereof in the presence of a fused metal chloride salt medium, which medium is capable of dissolving sulfurcontaining organic compounds present in the coal and which has a melting point below the digestion temperature; passing anhydrous hydrogen chloride into the digestion zone and removing from the digestion zone desulfurized coal. Subsequent refining of the desulfurized coal is also disclosed.
- This invention relates to a process for the desulfurization of coal which contains pyritic sulfur and sulfurcontaining organic compounds comprising: digesting, in a digestion zone, the coal and a Group IA or' IIA metal oxide salt or mixtures thereof in the presence of a fused metal chloride salt medium, which medium is capable of dissolving sulfur-containing organic compounds present in the coal and which has a melting point below the digestion temperature, until at least part of the dissolved sulfurcontainig organic compounds and pyritic sulfur has been converted to Group IA or IIA metal sulfides; feeding anhydrous hydrogen chloride to the digestion zone subsequent to the digestion period to convert the formed Group IA or IIA metal sulfides to Group IA or IIA metal chlorides respectively and hydrogen sulfide; and removing from the digestion zone an at least partially molten mixture containing desulfurized coal, the formed Group IA or IIA metal chloride salts and the metal choride salt medium.
- Digestion temperatures are within the range of from about 400 to about 600C. Pressures for the digestion are generally atmospheric and are not critical to the process.
- the fused metal chloride salt medium can be either a single metal chloride salt or a mixture of such salts. As before said, the fused metal chloride salt medium must have a meltingpoint below the digestion temperature and be capable of dissolving sulfur-containing organic compounds found in the coal. The extent of the solubility of the sulfur-containing organic compounds in the fused salt medium should be to the extent that at least 50 percent of the original sulfur'containing or ganic compounds in the coal will be dissolved.
- Examples of the single metal chloride salts which may be utilized as the medium are manganese chloride, ferric chloride, cupurous chloride, zinc chloride, stannous chloride, bismuth trichloride, cadmium chloride and the like.
- Exemplary of mixtures of metal chloride salts useful for the purpose of this invention are sodium chloride-manganese chloride, ferric chloride-cobalt dichloride, cupuric chloride-zinc chloride, zinc chloridelead dichloride, etc. The exact proportions of the salts making up the mixtures will, of course, be determined by the resulting melting point of the mixtures which point must be below the digestion temperature.
- salts whether they be used singularly or in mixtures, such as manganese chloride, ferric chloride, zinc chloride, stannous chloride, and bismuth trichloride are preferred.
- manganese chloride, ferric chloride, zinc chloride, stannous chloride, and bismuth trichloride are preferred.
- the most preferred salt is zinc chloride due to its availabil ity and low cost.
- Preferred mixtures of salts are zinc chloride-ferric chloride and zinc chloride-calcium chloride,
- the Group IA and IIA metal oxide salts utilized in the process of this invention are most preferably anhydrous. The absence of water in these salts is important from a safety standpoint as popping and spattering of the hot digestion mixture will be prevented.
- Examples of Group IA or IIA metal oxide salts which may be used in this invention are sodium oxide, magnesium oxide, calcium oxide, potassium oxide, cesium oxides, etc. Mixtures of these salts may, of course, be used.
- the preferred metal oxides are calcium oxide and sodium oxide as they are extremely economical reactants. Of these preferred salts, calcium oxide is most preferred.
- the digestion temperature should be within a range of from about 400 to about 600C. Selection of temperatures within this range will be dependent to some extent upon the particular type of coal beingdesulfurized as different coals have different temperatures at which serious thermal deterioration occurs. These deterioration temperatures are, of course, to be avoided. For example, temperatures below 550C should be utilized for some bituminous coals. Temperatures around 400-450C should be used for the lignites. Anthracite coal can withstand temperatures in the region of 500 to 550C.
- the digestion period should be that period of time which is sufficient to achieve at least substantially complete reaction of the organic sulfur compounds in solution and of the pyritic sulfur. Generally speaking, times ranging from one-fourth to 5 hours are sufficient with the time being dependent upon the amount of organic sulfur compounds and pyritic sulfur present and the type of coal being treated. From two to three hours have been found to be sufficient for coal which contains up to about 1.0 percent organic sulfur compounds and about 0.2 percent pyritic sulfur.
- the amount of Group IA or IIA metal oxide salt utilized will be that amount which provides at least a stoichiometric mole ratio of these salts to the sulfur present in the pyritic sulfur and in the dissolved organic sulfur compounds.
- a mole ratio of this salt to the sulfur should be at least 2:1.
- Group IIA metal oxide salts a mole ratio of 1:1 is sufficient. Amounts less than stoichiometric may be utilized, however such amounts do not result in high reaction efficiency. Amounts in excess of stoichiometric can also be used.
- the amount of metal chloride salt used as the medium should be that amount which will result in a relatively liquid digestion mixture. Generally speaking, such a mixture can be achieved by utilizing the salt medium in an amount so that the weight ratio of medium to coal and metal oxide salt is within the range of from about 6:1 to about 2:1.
- the coal, prior to digestion, should be prepared by grinding so that it will at least pass through a /z-inch mesh. This grinding of the coal is to hasten the dissolving of the sulfur-containing compounds in the fused metal chloride salt medium.
- the anhydrous hydrogen chloride fed to the digestion zone subsequent to the digestion period can be achieved by bubbling the gaseous acid through the digestion mixture, i.e., a mixture containing fused metal choride salt, coal and Group IA or IIA metal sulfides and remaining oxide salt.
- the amount of anhydrous hydrogen chloride used should be at least stoichiometric with relation to the amount of Group IA or IIA metal sulfides formed by the digestion. Amounts in excess of stoichiometric are, however, preferred.
- Amounts ranging up to 100 times stoichiometric quantities are most preferred.
- the H 8 can either be disposed of or can be utilized in processes having an H 8 demand.
- the at least partially molten material remaining in the zone is removed therefrom.
- the remaining material includes for the most part desulfurized coal, the metal chloride salt used as the medium and the formed Group 1A or IIA metal chlorides. Small amounts of Group IA or IIA metal oxides and sulfides may also be present. If it is desired, further refining of this material to cleanse the desulfurized coal of the greater portions of these various salts and reaction products may be effected.
- One refining technique comprises: cooling the removed at least partially molten material so as to solidify the molten components; crushing the solidified material; extracting from the crushed material, with alcohol, at least part of the metal chloride salt used as the medium and the formed Group IA or IIA metal chlorides; and separating the desulfurized coal from the alcoholsalt solution.
- the desulfurized coal may be even further refined by contacting the desulfurized coal with a dilute aqueous acid to extract any remaining salts or metal sulfides and separating the coal from the dilute aqueous acid-salt-sulfide solution.
- the recovered desulfurized coal can then be dried and pelletized to a form for consumption.
- Cooling of the removed material is necessary to get it in a slag form, i.e., an all solid form, which is suitable for further processing.
- a slag form i.e., an all solid form
- the material should be cooled so that it has a temperature lower than the boiling point of the alcohol to be used. This cooling can be achieved by placing the material in a cooled vessel until it has reached the desired temperature.
- the material After the material has been cooled it is desirable that it be crushed so that it will have a size which is favorable to the kinetics of extraction and which allows for easy handling. Generally speaking the material should be crushed so that is can pass through a /2-inch or A-inch mesh. Crushing can be achieved by passing the material through a ball mill or a roller mill.
- the crushed material is then subjected to alcohol extraction to remove the metal chloride salt which was used as the medium and the formed alkali or alkaline earth metal salts.
- alcohols can be utilized, for example, methanol, ethanol, butanol, isopropanol, pentanol, tertiary butanol, propanol, etc., are all useful. This extraction can be achieved by merely placing the crushed material in an alcohol bath with stirring.
- the extraction with alcohol of the various mentioned salts from the crushed material permits a variation in the process of this invention. It is possible indeed sometimes desirable to contact the crushed material with an alcohol-hydrogen chloride solution. By so doing, the introduction of anhydrous hydrogen chloride to the digestion zone may be eliminated.
- the hydrogen chloride in the alcohol will perform the same function as the anhydrous hydrogen chloride feed to the digestion zone. In other words, the hydrogen chloride in the alcohol solution will react with the formed Group IA or IIA metal sulfides to yield Group IA or IIA metal chlorides, respectively, with the evolution of hydrogen sulfide.
- the alcohol will then act to dissolve these formed chlorides so that they may be extracted from the desulfurized coal.
- the amount of HCl used with the alcohol is the same as the amount used in the first described embodiment where anhydrous HCl is fed to the digestion zone.
- the alcohol and its dissolved salts are removed from the solid desulfurized coal. This can be achieved by any of the well-known solid-liquid separations known to those skilled in the art. For example, filtration, centrifuging, decantation, etc., can be used.
- the alcohol-salt solution can be optionally fed to distillation so that the alcohol may be distilled from the salts and recycled back to the extraction step.
- the salts which have been separated from the alcohol can be recycled to the digestion zone.
- the desulfurized coal which has been separated from the alcohol-salt solution will still contain small amounts, i.e., less than 5 weight percent, of the metal chloride salts medium and Group IA or IIA metal sulfides, chlorides and oxides.
- these small amounts of impurities can be reduced by contacting the desulfurized coal with a dilute aqueous acid. e.g., a five percent hydrogen chloride solution. Filtration is then utilized to recover the desulfurized coal.
- the recovered desulfurized coal can then be dried with heat and may be further pelletized so as to achieve a desirable commereial form.
- the process of this invention may be utilized to desulfurize many types of coal. For example, it may be utilized to desulfurize anthracite, bituminous. subbituminous, and lignite types of coal.
- the sulfurcontaining organic compounds found in these types of coal generally are organic compounds which have a carbon-sulfur-carbon bond or a carbon-sulfur-sulfurcarbon bond in their structure.
- the digestion reactor consisted of a small vertical muffle furnace lined with a graphite sleeve. Inside of the sleeve was placed a glass reactor tube in which the digestions were to take place. Temperatures were controlled by way of a thermacouple placed in a glass tube which was inserted into the digestion zone. A glass dip tube was inserted into the glass reactor tube to provide a mode for anhydrous hydrogen chloride addition. A T-shaped glass tube was placed into the digestion zone to allow for a nitrogen purge during digestion. The acid and alcohol extraction were performed either in beakers or in extraction thimbles.
- EXAMPLE I A metallurgical coal containing from about 1.0 to about 1.2 percent total sulfur was crushed to-a 14 inch size. Six grams of the coal, along with 30 grams of zinc chloride and 3 grams of calcined lime were heated together in the digestion zone to a temperature of 450C for 2 hours. After this period anhydrous hydrogen chloride was bubbled through the glass dip tube for one-half hour. The resultant mass was then dumped from the digestion zone and cooled. The cooled mate rial was ground to about -16 mesh and extracted with isopropanol in a beaker for about three-fourths of an hour. The resultant mass was separated from the isopropanol-salt solution and contacted with 5 percent aqueous hydrogen chloride solution for one hour. The remaining solids were filtered from the acid solution and dried by heating. It was found by X-ray fluorescence that 62.1 percent of the total sulfur had been removed from the coal.
- Example II The coal of Example I was used for Example II. Twenty-five grams of zinc chloride, 3 grams of lime and 5 grams of the coal were heated together in a digestion zone to a temperature of 500C for 2% hours. After this period anhydrous hydrogen chloride was bubbled through the glass dip tube for one hour. The resultant mass was then dumped from the digestion zone and cooled. The cooled material was ground to about 16 mesh and extracted with methanol for 2 hours. X-ray fluorescence showed that 54.6 percent of the original sulfur present was removed.
- EXAMPLE III Five grams of the coal, 25 grams of zinc chloride and 3 grams of lime were heated together in the digestion zone to a temperature of 400C for 3%hours. After this period anhydrous hydrogen chloride was bubbled through the glass dip tube for one-half hour. The resul tant mass was dumped from the digestion zone and cooled. The cooled material was ground to about -l6 mesh and extracted with methanol for about 2 hours. X-ray fluorescence showed that 64.6 percent of the original sulfur present had been removed.
- a process for the desulfurization of coal which contains pyritic sulfur and sulfur-containing organic compounds comprising:
- a. digesting. in a digestion zone the coal and a Group IA or IIA metal oxide salt or mixtures thereof in the presence of a fused metal chloride salt medium, which medium is capable of dissolving at least percent of the sulfur-containing organic compounds present in the coal and which has a melting point below the digestion temperature, until at least part of the pyritic sulfur and the dissolved sulfur-containing organic compounds have been converted to Group IA or IIA metal sulfides; said metal oxide salt or mixtures thereof being present in an amount which provides at least a stoichiometric mole ratio of said metal oxide salt to the amount of sulfur present in said pyritic sulfur and said dissolved organic compounds, said fused metal chloride salt medium being present in an amount which will result in a relatively liquid digestion mixture;
- metal oxide salt is calcium oxide or sodium oxide.
- metal chloride salt medium is zinc chloride, a mix of zinc chloride and ferric chloride or a mix of zinc chloride and calcium chloride.
- metal oxide salt is calcium oxide or sodium oxide.
- the metal chloride salt medium is zinc chloride, a mix of zinc chloride and ferric chloride or a mix of zinc chloride and calcium chloride.
- a process for the desulfurization of coal'which contains pyritic sulfur and sulfur-containing organic compounds comprising:
- metal oxide salt is calcium oxide or sodium oxide.
- the metal chloride salt medium is zinc chloride, a mix of zinc chloride and ferric chloride or a mix of zinc chloride and calcium chloride.
Abstract
A process is disclosed for desulfurization of coal which comprises: digesting, in a digestion zone, coal and a Group IA or IIA metal oxide or mixtures thereof in the presence of a fused metal chloride salt medium, which medium is capable of dissolving sulfur-containing organic compounds present in the coal and which has a melting point below the digestion temperature; passing anhydrous hydrogen chloride into the digestion zone and removing from the digestion zone desulfurized coal. Subsequent refining of the desulfurized coal is also disclosed.
Description
United States Patent 1191 Sanders 1 DESULFURIZATION OF COAL [75] Inventor: Robert N. Sanders, Baton Rouge,
[73] Assignee: Ethyl Corporation, Richmond, Va.
[22] Filed: Dec. 17,1973
[21] Appl. No.: 425,189
52 us. Cl .I 44/1 R 51 Int. cl. c101. 5/00 [58] Field of Search 44/1 R; 201/17; 75/6 [56] References Cited UNITED STATES PATENTS 887,145 5/1908 Stoner 201/17 3,327,402 6/1967 Lamb et 211.. 44/1 R 3,640,016 2/1972 Lee et a1. 44/1 R 3,768,988 10/1973 Meyers 44/1 R Primary Examiner-Carl F. Dees Attorney, Agent, or FirmDona1d L. Johnson; John F. Sieberth; Paul H. Leonard 5 7] ABSTRACT A process is disclosed for desulfurization of coal which comprises: digesting, in a digestion zone, coal and a Group [A or 11A metal oxide or mixtures thereof in the presence of a fused metal chloride salt medium, which medium is capable of dissolving sulfurcontaining organic compounds present in the coal and which has a melting point below the digestion temperature; passing anhydrous hydrogen chloride into the digestion zone and removing from the digestion zone desulfurized coal. Subsequent refining of the desulfurized coal is also disclosed.
21 Claims, N0 Drawings DESULFURIZATION OF COAL BACKGROUND OF THE INVENTION It is estimated that by 1975 the U.S. will have a coal production ranging from 600 to 800 million metric tons. The majority of this coal, about 70 percent, will be burned directly for the generation of electricity and steam power, for comfort heat, for metallurgical processes and for the firing of ceramic productions. Since almost all coal contains both organic and inorganic sulfur compounds, the polution burden placed on the environment upon burning the coal can be quite large as the burning produces sulfur oxides which are contaminants, For example, a one-million kilowatt power plant (which is not unusually large) burning coal containing 3.5 percent sulfur (which is not unusually high) emits sulfur oxides equivalent to about 1,000 tons of sulfuric acid per day. From these facts it can be seen that the usefulness of coal for its energy value is somewhat tempered by the polution problems attenuant with its use. There are many studies now being made on an.international scale for solving the coal polution problem. Some efforts are directed towards cleaning up the stack gasses from the coal-burning furnaces. The stack gas directed solutions are generally hampered by huge capital outlays. Other solutions which would not require such capital outlays are those directed towards the desulfurization of coal prior to its burning. To date no generally known economical desulfurization process has been developed.
It is therefore an object of this invention to provide a process for the desulfurization of coal which is relatively uncomplicated and which is economically attractive.
THE INVENTION This invention relates to a process for the desulfurization of coal which contains pyritic sulfur and sulfurcontaining organic compounds comprising: digesting, in a digestion zone, the coal and a Group IA or' IIA metal oxide salt or mixtures thereof in the presence of a fused metal chloride salt medium, which medium is capable of dissolving sulfur-containing organic compounds present in the coal and which has a melting point below the digestion temperature, until at least part of the dissolved sulfurcontainig organic compounds and pyritic sulfur has been converted to Group IA or IIA metal sulfides; feeding anhydrous hydrogen chloride to the digestion zone subsequent to the digestion period to convert the formed Group IA or IIA metal sulfides to Group IA or IIA metal chlorides respectively and hydrogen sulfide; and removing from the digestion zone an at least partially molten mixture containing desulfurized coal, the formed Group IA or IIA metal chloride salts and the metal choride salt medium. Digestion temperatures are within the range of from about 400 to about 600C. Pressures for the digestion are generally atmospheric and are not critical to the process. percent The fused metal chloride salt medium can be either a single metal chloride salt or a mixture of such salts. As before said, the fused metal chloride salt medium must have a meltingpoint below the digestion temperature and be capable of dissolving sulfur-containing organic compounds found in the coal. The extent of the solubility of the sulfur-containing organic compounds in the fused salt medium should be to the extent that at least 50 percent of the original sulfur'containing or ganic compounds in the coal will be dissolved.
Examples of the single metal chloride salts which may be utilized as the medium are manganese chloride, ferric chloride, cupurous chloride, zinc chloride, stannous chloride, bismuth trichloride, cadmium chloride and the like. Exemplary of mixtures of metal chloride salts useful for the purpose of this invention are sodium chloride-manganese chloride, ferric chloride-cobalt dichloride, cupuric chloride-zinc chloride, zinc chloridelead dichloride, etc. The exact proportions of the salts making up the mixtures will, of course, be determined by the resulting melting point of the mixtures which point must be below the digestion temperature.
As the high solubility in alcohol of the metal chloride salts making up the medium will be highly desirable for subsequent refining of the desulfurized coal, as hereinafter described, salts, whether they be used singularly or in mixtures, such as manganese chloride, ferric chloride, zinc chloride, stannous chloride, and bismuth trichloride are preferred. Of these preferred salts, the most preferred salt is zinc chloride due to its availabil ity and low cost. Preferred mixtures of salts are zinc chloride-ferric chloride and zinc chloride-calcium chloride,
The Group IA and IIA metal oxide salts utilized in the process of this invention are most preferably anhydrous. The absence of water in these salts is important from a safety standpoint as popping and spattering of the hot digestion mixture will be prevented. Examples of Group IA or IIA metal oxide salts which may be used in this invention are sodium oxide, magnesium oxide, calcium oxide, potassium oxide, cesium oxides, etc. Mixtures of these salts may, of course, be used. The preferred metal oxides are calcium oxide and sodium oxide as they are extremely economical reactants. Of these preferred salts, calcium oxide is most preferred.
The digestion temperature should be within a range of from about 400 to about 600C. Selection of temperatures within this range will be dependent to some extent upon the particular type of coal beingdesulfurized as different coals have different temperatures at which serious thermal deterioration occurs. These deterioration temperatures are, of course, to be avoided. For example, temperatures below 550C should be utilized for some bituminous coals. Temperatures around 400-450C should be used for the lignites. Anthracite coal can withstand temperatures in the region of 500 to 550C.
The digestion period should be that period of time which is sufficient to achieve at least substantially complete reaction of the organic sulfur compounds in solution and of the pyritic sulfur. Generally speaking, times ranging from one-fourth to 5 hours are sufficient with the time being dependent upon the amount of organic sulfur compounds and pyritic sulfur present and the type of coal being treated. From two to three hours have been found to be sufficient for coal which contains up to about 1.0 percent organic sulfur compounds and about 0.2 percent pyritic sulfur.
Quantitatively, the amount of Group IA or IIA metal oxide salt utilized will be that amount which provides at least a stoichiometric mole ratio of these salts to the sulfur present in the pyritic sulfur and in the dissolved organic sulfur compounds. In other words, when utilizing Group IA metal oxide salts a mole ratio of this salt to the sulfur should be at least 2:1. When utilizing Group IIA metal oxide salts a mole ratio of 1:1 is sufficient. Amounts less than stoichiometric may be utilized, however such amounts do not result in high reaction efficiency. Amounts in excess of stoichiometric can also be used. In fact, mole ratios up to 4:1 for Group IA metal oxide salts and up to 2:1 for Group IIA metal oxide salts are preferred as reaction kinetics are improved by the presence of the excess of these salts. For calcium oxide, a highly preferred salt, it has been found that a mole ratio of from about 1.2:1 to 1.5:1 is
most preferred.
The amount of metal chloride salt used as the medium should be that amount which will result in a relatively liquid digestion mixture. Generally speaking, such a mixture can be achieved by utilizing the salt medium in an amount so that the weight ratio of medium to coal and metal oxide salt is within the range of from about 6:1 to about 2:1.
The coal, prior to digestion, should be prepared by grinding so that it will at least pass through a /z-inch mesh. This grinding of the coal is to hasten the dissolving of the sulfur-containing compounds in the fused metal chloride salt medium. The anhydrous hydrogen chloride fed to the digestion zone subsequent to the digestion period can be achieved by bubbling the gaseous acid through the digestion mixture, i.e., a mixture containing fused metal choride salt, coal and Group IA or IIA metal sulfides and remaining oxide salt. The amount of anhydrous hydrogen chloride used should be at least stoichiometric with relation to the amount of Group IA or IIA metal sulfides formed by the digestion. Amounts in excess of stoichiometric are, however, preferred. Amounts ranging up to 100 times stoichiometric quantities are most preferred. By passing the anhydrous hydrogen chloride through the digestion mixture the Group IA and IIA metal sulfides are converted to Group IA or IIA metal chlorides, respectively, with the evolution of gaseous H 8 from the digestion zone. The H 8 can either be disposed of or can be utilized in processes having an H 8 demand.
After the anhydrous hydrogen chloride has been fed to the digestion zone the at least partially molten material remaining in the zone is removed therefrom. The remaining material includes for the most part desulfurized coal, the metal chloride salt used as the medium and the formed Group 1A or IIA metal chlorides. Small amounts of Group IA or IIA metal oxides and sulfides may also be present. If it is desired, further refining of this material to cleanse the desulfurized coal of the greater portions of these various salts and reaction products may be effected.
One refining technique comprises: cooling the removed at least partially molten material so as to solidify the molten components; crushing the solidified material; extracting from the crushed material, with alcohol, at least part of the metal chloride salt used as the medium and the formed Group IA or IIA metal chlorides; and separating the desulfurized coal from the alcoholsalt solution. Optionally, the desulfurized coal may be even further refined by contacting the desulfurized coal with a dilute aqueous acid to extract any remaining salts or metal sulfides and separating the coal from the dilute aqueous acid-salt-sulfide solution. The recovered desulfurized coal can then be dried and pelletized to a form for consumption.
Cooling of the removed material is necessary to get it in a slag form, i.e., an all solid form, which is suitable for further processing. As alcohol is to be utilized later in the refining scheme, the material should be cooled so that it has a temperature lower than the boiling point of the alcohol to be used. This cooling can be achieved by placing the material in a cooled vessel until it has reached the desired temperature.
After the material has been cooled it is desirable that it be crushed so that it will have a size which is favorable to the kinetics of extraction and which allows for easy handling. Generally speaking the material should be crushed so that is can pass through a /2-inch or A-inch mesh. Crushing can be achieved by passing the material through a ball mill or a roller mill.
The crushed material is then subjected to alcohol extraction to remove the metal chloride salt which was used as the medium and the formed alkali or alkaline earth metal salts. Various alcohols can be utilized, for example, methanol, ethanol, butanol, isopropanol, pentanol, tertiary butanol, propanol, etc., are all useful. This extraction can be achieved by merely placing the crushed material in an alcohol bath with stirring.
The extraction with alcohol of the various mentioned salts from the crushed material permits a variation in the process of this invention. It is possible indeed sometimes desirable to contact the crushed material with an alcohol-hydrogen chloride solution. By so doing, the introduction of anhydrous hydrogen chloride to the digestion zone may be eliminated. The hydrogen chloride in the alcohol will perform the same function as the anhydrous hydrogen chloride feed to the digestion zone. In other words, the hydrogen chloride in the alcohol solution will react with the formed Group IA or IIA metal sulfides to yield Group IA or IIA metal chlorides, respectively, with the evolution of hydrogen sulfide. The alcohol will then act to dissolve these formed chlorides so that they may be extracted from the desulfurized coal. The amount of HCl used with the alcohol is the same as the amount used in the first described embodiment where anhydrous HCl is fed to the digestion zone.
After extraction the alcohol and its dissolved salts are removed from the solid desulfurized coal. This can be achieved by any of the well-known solid-liquid separations known to those skilled in the art. For example, filtration, centrifuging, decantation, etc., can be used.
The alcohol-salt solution can be optionally fed to distillation so that the alcohol may be distilled from the salts and recycled back to the extraction step. The salts which have been separated from the alcohol can be recycled to the digestion zone.
The desulfurized coal which has been separated from the alcohol-salt solution will still contain small amounts, i.e., less than 5 weight percent, of the metal chloride salts medium and Group IA or IIA metal sulfides, chlorides and oxides. Optionally, these small amounts of impurities can be reduced by contacting the desulfurized coal with a dilute aqueous acid. e.g., a five percent hydrogen chloride solution. Filtration is then utilized to recover the desulfurized coal. The recovered desulfurized coal can then be dried with heat and may be further pelletized so as to achieve a desirable commereial form.
The process of this invention may be utilized to desulfurize many types of coal. For example, it may be utilized to desulfurize anthracite, bituminous. subbituminous, and lignite types of coal. The sulfurcontaining organic compounds found in these types of coal generally are organic compounds which have a carbon-sulfur-carbon bond or a carbon-sulfur-sulfurcarbon bond in their structure.
The following non-limiting examples will further illustrate the process of this invention. The equipment used in each example was essentially the same. The digestion reactor consisted of a small vertical muffle furnace lined with a graphite sleeve. Inside of the sleeve was placed a glass reactor tube in which the digestions were to take place. Temperatures were controlled by way of a thermacouple placed in a glass tube which was inserted into the digestion zone. A glass dip tube was inserted into the glass reactor tube to provide a mode for anhydrous hydrogen chloride addition. A T-shaped glass tube was placed into the digestion zone to allow for a nitrogen purge during digestion. The acid and alcohol extraction were performed either in beakers or in extraction thimbles.
EXAMPLE I A metallurgical coal containing from about 1.0 to about 1.2 percent total sulfur was crushed to-a 14 inch size. Six grams of the coal, along with 30 grams of zinc chloride and 3 grams of calcined lime were heated together in the digestion zone to a temperature of 450C for 2 hours. After this period anhydrous hydrogen chloride was bubbled through the glass dip tube for one-half hour. The resultant mass was then dumped from the digestion zone and cooled. The cooled mate rial was ground to about -16 mesh and extracted with isopropanol in a beaker for about three-fourths of an hour. The resultant mass was separated from the isopropanol-salt solution and contacted with 5 percent aqueous hydrogen chloride solution for one hour. The remaining solids were filtered from the acid solution and dried by heating. It was found by X-ray fluorescence that 62.1 percent of the total sulfur had been removed from the coal.
EXAMPLE II The coal of Example I was used for Example II. Twenty-five grams of zinc chloride, 3 grams of lime and 5 grams of the coal were heated together in a digestion zone to a temperature of 500C for 2% hours. After this period anhydrous hydrogen chloride was bubbled through the glass dip tube for one hour. The resultant mass was then dumped from the digestion zone and cooled. The cooled material was ground to about 16 mesh and extracted with methanol for 2 hours. X-ray fluorescence showed that 54.6 percent of the original sulfur present was removed.
EXAMPLE III Five grams of the coal, 25 grams of zinc chloride and 3 grams of lime were heated together in the digestion zone to a temperature of 400C for 3%hours. After this period anhydrous hydrogen chloride was bubbled through the glass dip tube for one-half hour. The resul tant mass was dumped from the digestion zone and cooled. The cooled material was ground to about -l6 mesh and extracted with methanol for about 2 hours. X-ray fluorescence showed that 64.6 percent of the original sulfur present had been removed.
I claim: I
l. A process for the desulfurization of coal which contains pyritic sulfur and sulfur-containing organic compounds comprising:
a. digesting. in a digestion zone, the coal and a Group IA or IIA metal oxide salt or mixtures thereof in the presence of a fused metal chloride salt medium, which medium is capable of dissolving at least percent of the sulfur-containing organic compounds present in the coal and which has a melting point below the digestion temperature, until at least part of the pyritic sulfur and the dissolved sulfur-containing organic compounds have been converted to Group IA or IIA metal sulfides; said metal oxide salt or mixtures thereof being present in an amount which provides at least a stoichiometric mole ratio of said metal oxide salt to the amount of sulfur present in said pyritic sulfur and said dissolved organic compounds, said fused metal chloride salt medium being present in an amount which will result in a relatively liquid digestion mixture;
b. feeding anhydrous hydrogen chloride to the digestion zone subsequent to the digestion period to convert the formed Group IA or IIA metal sulfides to Group IA or IIA metal chlorides respectively and hydrogen sulfide; and
c. removing from the digestion zone an at least partially molten mixture containing desulfurized coal, the formed Group IA or IIA metal chloride salts and the metal chloride salt medium.
2. The process of claim I wherein the metal oxide salt is calcium oxide or sodium oxide.
3. The process of claim 1 wherein the metal oxide salt is calcium oxide.
4. The process of claim 1 wherein the metal chloride salt medium is zinc chloride, a mix of zinc chloride and ferric chloride or a mix of zinc chloride and calcium chloride.
5. The process of claim 1 wherein the metal chloride salt medium in zinc chloride.
6. The process of claim 1 wherein the desulfurized coalin the molten mixture is separated from at least part of the formed chloride salts and the metal chloride salt medium by a refining process which comprises:
a. cooling the removed at least partially molten material so as to solidify the molten components;
b. crushing the solidified material;
0. extracting from the crushed material with alcohol at least part of the metal chloride salt used as the medium and the formed Group IA or IIA metal chlorides; and
d. separating the desulfurized coal from the alcoholsalt solution.
7. The process of claim 6 wherein the separated desulfurized coal is further refined to reduce the content of any remaining metal chloride salt medium and Group IA or IIA metal sulfides or chlorides by a second refining process which comprises:
a. contacting the separated desulfurized coal with a dilute aqueous acid to extract at least part of the remaining metal chloride salt medium and the remaining Group IA or IIA metal sulfides or chlorides in the separated desulfurized coal;
b. separating the contacted desulfurized coal from the resultant dilute aqueous acid-metal chloride salt'sulfide solution; and
c. drying and pelletizing the dsulfurizcd coal from Step (b).
8. The process of claim 6 wherein the metal oxide salt is calcium oxide or sodium oxide.
9. The process of claim 6 wherein the metal oxide salt is calcium oxide.
10. The process of claim 6 wherein the metal chloride salt medium is zinc chloride, a mix of zinc chloride and ferric chloride or a mix of zinc chloride and calcium chloride.
11. The process of claim 6 wherein the metal chloride salt medium is zinc chloride.
12. A process for the desulfurization of coal'which contains pyritic sulfur and sulfur-containing organic compounds comprising:
a. digesting, in a digestion zone, the coal and a Group IA or IIA metal oxide salt or mixtures thereofin the presence of a fused metal chloride salt medium, which medium is capable of dissolving at least 50 percent of the sulfur-containing organic compounds present in the coal and which has a melting point below the digestion temperature, until at least part of the pyritic sulfur and the dissolved sulfur-containing organic compounds have been converted to Group IA or IIA metal sulfide; said metal oxide salt or mixtures thereof being present in an amount which provides at least a stoichiometric mole ratio of said metal oxide salt to the amount of sulfur present in said pyritic sulfur and said dissolved organic compounds, said fused metal chloride salt medium being present in an amount which will result in a relatively liquid digestion mixture;
b. removing from the digestion zone an at least partially molten mixture containing desulfurized coal, the formed Group IA or IIA metal sulfide and the metal chloride medium;
c. cooling the removed at least partially molten material so as to solidify the molten components;
d. crushing the solidified material;
e. contacting the crushed material with an alcoholhydrogen chloride solution so as to convert'the formed Group IA or IIA metal sulfides to Group IA or IIA metal chlorides respectively and hydrogen sulfide, and to extract from the desulfurized coal at least part of the metal chloride salt used as the medium and the formed Group IA or IIA metal chlorides; and
f. separating the desulfurized coal from the alcoholsalt solution.
13. The process of claim 12 wherein the separated desulfurized coal is further refined to reduce the content of any remaining metal chloride salt medium and Group IA or IIA metal chlorides or sulfides by a second refining process which comprises:
a. contacting the separated desulfurized coal with a dilute aqueous acid to extract at least part of the remaining metal chloride salt medium and the remaining Group IA or IIA metal sulfides or chlorides in the separated desulfurized coal;
b. separating the contacted desulfurized coal from the resultant dilute aqueous acid-metal chloride salt-sulfide solution; and
c. drying and pelletizing the desulfurized coal from Step (b).
14. The process of claim 12 wherein the metal oxide salt is calcium oxide or sodium oxide.
15. The process of claim 12 wherein the metal oxide salt is calcium oxide. 7 g
16. The process of claim 12 wherein the metal chloride salt medium is zinc chloride, a mix of zinc chloride and ferric chloride or a mix of zinc chloride and calcium chloride.
17. The process of claim 12 wherein the metal chloride salt medium iszinc chloride.
18. The process of claim 1, wherein when said metal oxide salt is a Group IA metal oxide salt, the mole ratio of said salt to said sulfur ranges from about 2:1 to about 4:1; and when said metal oxide salt is a Group IIA metal oxide salt, the mole ratio of said salt to said sulfur ranges from about 1:1 to about 2:1.
19. The process of claim 1; wherein said fused metal chloride salt medium is present in a weight ratio range of said medium to said coal and said metal oxide salt of from about 6:1 to about 2.1.
20. The process of claim 12, wherein when said metal oxide salt is a Group IA metal oxide salt, the mole ratio of said salt to said sulfur ranges from about 2:1 to about 4:1; and when said metal oxide salt is a Group IIA metal oxide salt, the mole ratio of said salt to said sulfur ranges form about 1:1 to about 2:1.
21. The process of claim 12, wherein said fused metal chloride salt medium is present in a weight ratio range of said medium to said coal and said metal oxide salt of from about 6:1 to about 2:1.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. I 3 909 213 DATED September 30, 1975 INVENTOR(S) Robert N. Sanders It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 1, line 59, "percent" should be omitted. Column 5, line 56 "3-1/4 hours" should read 2-1/4 hours Column 6 line 37, "in" should read is Column 8, line 35, "2.1" should read 2:1 Column 8, line 41, "form" should read from Signed and sealed this sixteenth D3) Of December 1975 [SEAL] A ttest:
RUTH C. MRLSON C. MARSHALL DANN Altsllllg Ojjleer Commissioner ofParents and Trademarks
Claims (21)
1. A PROCESS FOR THE DESULFURIZATION OF COAL WHICH CONTAINS PYRITIC SULFUR AND SULFUR-CONTAINING ORGANIC COMPOUNDS COMPRISING: A. DIGESTING IN A DIGESTION ZONE THE COAL AND A GROUP 1A OR IIA METAL OXIDE SALT OR MIXTURES THEREOF IN THE PRESENCE OF A FUSED METAL CHLORIDE SALT MEDIUM, WHICH MEDIUM IS CAPABLE OF DISSOLVING AT LEAST 50 PERCENT OF THE SULFUR-CONTAINING ORGANIC COMPOUNDS PRESENT IN THE COAL AND WHICH HAS A MELTING POINT BELOW BELOW THE DIGESTION TEMPERATURE UNTIL AT LEAST PART OF THE PYRITIC SULFUR AND THE DISSOLVED SULFURCONTAINING ORGANIC COMPOUND HAVE BEEN CONVERTED TO GROUP IA OR IIA METAL SULFIDES SAND METAL OXIDE OR MIXTURES THEREOF BEING PRESENT IN AN AMOUNT WHICH PROVIDES AT LEAST A STOICHIOMETRIC MOLE RATIO OF SAID METAL OXIDE SALT TO THE AMOUNT OF SULFUR PRESENT IN SAID PURITIC SULFUR AND SAID DISSOLVED ORGANIC COMPOUNDS SAID FUSED METAL CHLORIDE SALT MEDIUM BEING PRESENT IN AN AMOUNT WHICH WILL RESULT IN A RELATIVELY LIQUID DIGESTION MIXTURE, B. FEEDING ANHYDROUS HYDROGEN CHLORIDE TO THE DIGESTION ZONE SUBSEQUENT TO THE DIGESTION PERIOD TO CONVERT THE FOMRED GROUP IA OR IIA METAL SULFIDES GROUP IA OR IIA METAL CHLORIDES RESPECTIVELY AND HYDROGEN SULFIDE AND C. REMOVING FRO THE DIGESTION ZONE AN AT LEAST PARTIALLY MOLTEN MIXTURE CONTAINING DESULFURIZED COAL THE FORMED GROUP IA OR IIA METAL CHLORIDE SALTS AND THE METAL CHLORIDE SALT MEDIUM.
2. The process of claim 1 wherein the metal oxide salt is calcium oxide or sodium oxIde.
3. The process of claim 1 wherein the metal oxide salt is calcium oxide.
4. The process of claim 1 wherein the metal chloride salt medium is zinc chloride, a mix of zinc chloride and ferric chloride or a mix of zinc chloride and calcium chloride.
5. The process of claim 1 wherein the metal chloride salt medium in zinc chloride.
6. The process of claim 1 wherein the desulfurized coal in the molten mixture is separated from at least part of the formed chloride salts and the metal chloride salt medium by a refining process which comprises: a. cooling the removed at least partially molten material so as to solidify the molten components; b. crushing the solidified material; c. extracting from the crushed material with alcohol at least part of the metal chloride salt used as the medium and the formed Group IA or IIA metal chlorides; and d. separating the desulfurized coal from the alcohol-salt solution.
7. The process of claim 6 wherein the separated desulfurized coal is further refined to reduce the content of any remaining metal chloride salt medium and Group IA or IIA metal sulfides or chlorides by a second refining process which comprises: a. contacting the separated desulfurized coal with a dilute aqueous acid to extract at least part of the remaining metal chloride salt medium and the remaining Group IA or IIA metal sulfides or chlorides in the separated desulfurized coal; b. separating the contacted desulfurized coal from the resultant dilute aqueous acid-metal chloride salt-sulfide solution; and c. drying and pelletizing the dsulfurized coal from Step (b).
8. The process of claim 6 wherein the metal oxide salt is calcium oxide or sodium oxide.
9. The process of claim 6 wherein the metal oxide salt is calcium oxide.
10. The process of claim 6 wherein the metal chloride salt medium is zinc chloride, a mix of zinc chloride and ferric chloride or a mix of zinc chloride and calcium chloride.
11. The process of claim 6 wherein the metal chloride salt medium is zinc chloride.
12. A process for the desulfurization of coal which contains pyritic sulfur and sulfur-containing organic compounds comprising: a. digesting, in a digestion zone, the coal and a Group IA or IIA metal oxide salt or mixtures thereof in the presence of a fused metal chloride salt medium, which medium is capable of dissolving at least 50 percent of the sulfur-containing organic compounds present in the coal and which has a melting point below the digestion temperature, until at least part of the pyritic sulfur and the dissolved sulfur-containing organic compounds have been converted to Group IA or IIA metal sulfide; said metal oxide salt or mixtures thereof being present in an amount which provides at least a stoichiometric mole ratio of said metal oxide salt to the amount of sulfur present in said pyritic sulfur and said dissolved organic compounds, said fused metal chloride salt medium being present in an amount which will result in a relatively liquid digestion mixture; b. removing from the digestion zone an at least partially molten mixture containing desulfurized coal, the formed Group IA or IIA metal sulfide and the metal chloride medium; c. cooling the removed at least partially molten material so as to solidify the molten components; d. crushing the solidified material; e. contacting the crushed material with an alcohol-hydrogen chloride solution so as to convert the formed Group IA or IIA metal sulfides to Group IA or IIA metal chlorides respectively and hydrogen sulfide, and to extract from the desulfurized coal at least part of the metal chloride salt used as the medium and the formed Group IA or IIA metal chlorides; and f. separating the desulfurized coal from the alcohol-salt solution.
13. The process of claim 12 wherein the separated desulfurized coal is further refined to reduce the content of any remaining metal chloride salt Medium and Group IA or IIA metal chlorides or sulfides by a second refining process which comprises: a. contacting the separated desulfurized coal with a dilute aqueous acid to extract at least part of the remaining metal chloride salt medium and the remaining Group IA or IIA metal sulfides or chlorides in the separated desulfurized coal; b. separating the contacted desulfurized coal from the resultant dilute aqueous acid-metal chloride salt-sulfide solution; and c. drying and pelletizing the desulfurized coal from Step (b).
14. The process of claim 12 wherein the metal oxide salt is calcium oxide or sodium oxide.
15. The process of claim 12 wherein the metal oxide salt is calcium oxide.
16. The process of claim 12 wherein the metal chloride salt medium is zinc chloride, a mix of zinc chloride and ferric chloride or a mix of zinc chloride and calcium chloride.
17. The process of claim 12 wherein the metal chloride salt medium is zinc chloride.
18. The process of claim 1, wherein when said metal oxide salt is a Group IA metal oxide salt, the mole ratio of said salt to said sulfur ranges from about 2:1 to about 4:1; and when said metal oxide salt is a Group IIA metal oxide salt, the mole ratio of said salt to said sulfur ranges from about 1:1 to about 2:1.
19. The process of claim 1, wherein said fused metal chloride salt medium is present in a weight ratio range of said medium to said coal and said metal oxide salt of from about 6:1 to about 2.1.
20. The process of claim 12, wherein when said metal oxide salt is a Group IA metal oxide salt, the mole ratio of said salt to said sulfur ranges from about 2:1 to about 4:1; and when said metal oxide salt is a Group IIA metal oxide salt, the mole ratio of said salt to said sulfur ranges form about 1:1 to about 2:1.
21. The process of claim 12, wherein said fused metal chloride salt medium is present in a weight ratio range of said medium to said coal and said metal oxide salt of from about 6:1 to about 2:
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US4022588A (en) * | 1976-03-05 | 1977-05-10 | Mobil Oil Corporation | Oxidative chemical removal of pyritic sulfur from coal by manganese, vanadium, and cerium oxidants |
US4092125A (en) * | 1975-03-31 | 1978-05-30 | Battelle Development Corporation | Treating solid fuel |
US4118200A (en) * | 1977-07-08 | 1978-10-03 | Cato Research Corporation | Process for desulfurizing coal |
US4127390A (en) * | 1977-08-25 | 1978-11-28 | Coalmet Corporation | Hydrodesulfurization of coal and the like |
US4167397A (en) * | 1978-03-31 | 1979-09-11 | Standard Oil Company | Coal desulfurization |
US4233034A (en) * | 1979-05-03 | 1980-11-11 | Union Oil Company Of California | Desulfurization of coal |
US4545891A (en) * | 1981-03-31 | 1985-10-08 | Trw Inc. | Extraction and upgrading of fossil fuels using fused caustic and acid solutions |
US4561859A (en) * | 1985-04-18 | 1985-12-31 | The United States Of America As Represented By The United States Department Of Energy | Low temperature aqueous desulfurization of coal |
US4586935A (en) * | 1984-09-21 | 1986-05-06 | Meridian Petroleums Ltd. | Method of preparing coal to increase its calorific value and making it safe for storage and transport |
US4640692A (en) * | 1985-07-26 | 1987-02-03 | Mobil Oil Corporation | Process for the elimination of pyrite |
EP0230500A1 (en) * | 1986-01-31 | 1987-08-05 | Charles H. Simpson | Method for removing pyritic, organic, and elemental sulfur from coal |
US4888029A (en) * | 1988-06-07 | 1989-12-19 | The Board Of Trustees Of Southern Illinois University | Desulfurization of carbonaceous materials |
US5037450A (en) * | 1990-04-12 | 1991-08-06 | University Of Cincinnati | Method and apparatus for desulfurizing and denitrifying coal |
US5059307A (en) * | 1981-03-31 | 1991-10-22 | Trw Inc. | Process for upgrading coal |
US5085764A (en) * | 1981-03-31 | 1992-02-04 | Trw Inc. | Process for upgrading coal |
US5350431A (en) * | 1992-05-11 | 1994-09-27 | Idemitsu Kosan Company Limited | Process for chemical desulfurization of coal |
CN104675430A (en) * | 2015-03-04 | 2015-06-03 | 山西潞安环保能源开发股份有限公司 | High-hydrogen-sulfide coal seam roadway construction advanced alkali injection process and alkali liquid formula |
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US887145A (en) * | 1907-11-09 | 1908-05-12 | Erastus L Stoner | Process of desulfurizing coke. |
US3327402A (en) * | 1964-12-28 | 1967-06-27 | Shell Oil Co | Solvent drying of coal fines |
US3640016A (en) * | 1969-03-28 | 1972-02-08 | Inst Gas Technology | Desulfurization of coal |
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Cited By (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4092125A (en) * | 1975-03-31 | 1978-05-30 | Battelle Development Corporation | Treating solid fuel |
US4022588A (en) * | 1976-03-05 | 1977-05-10 | Mobil Oil Corporation | Oxidative chemical removal of pyritic sulfur from coal by manganese, vanadium, and cerium oxidants |
US4118200A (en) * | 1977-07-08 | 1978-10-03 | Cato Research Corporation | Process for desulfurizing coal |
US4127390A (en) * | 1977-08-25 | 1978-11-28 | Coalmet Corporation | Hydrodesulfurization of coal and the like |
US4167397A (en) * | 1978-03-31 | 1979-09-11 | Standard Oil Company | Coal desulfurization |
US4233034A (en) * | 1979-05-03 | 1980-11-11 | Union Oil Company Of California | Desulfurization of coal |
US5059307A (en) * | 1981-03-31 | 1991-10-22 | Trw Inc. | Process for upgrading coal |
US4545891A (en) * | 1981-03-31 | 1985-10-08 | Trw Inc. | Extraction and upgrading of fossil fuels using fused caustic and acid solutions |
US5085764A (en) * | 1981-03-31 | 1992-02-04 | Trw Inc. | Process for upgrading coal |
US4586935A (en) * | 1984-09-21 | 1986-05-06 | Meridian Petroleums Ltd. | Method of preparing coal to increase its calorific value and making it safe for storage and transport |
US4561859A (en) * | 1985-04-18 | 1985-12-31 | The United States Of America As Represented By The United States Department Of Energy | Low temperature aqueous desulfurization of coal |
US4640692A (en) * | 1985-07-26 | 1987-02-03 | Mobil Oil Corporation | Process for the elimination of pyrite |
EP0230500A1 (en) * | 1986-01-31 | 1987-08-05 | Charles H. Simpson | Method for removing pyritic, organic, and elemental sulfur from coal |
US4888029A (en) * | 1988-06-07 | 1989-12-19 | The Board Of Trustees Of Southern Illinois University | Desulfurization of carbonaceous materials |
US5037450A (en) * | 1990-04-12 | 1991-08-06 | University Of Cincinnati | Method and apparatus for desulfurizing and denitrifying coal |
US5350431A (en) * | 1992-05-11 | 1994-09-27 | Idemitsu Kosan Company Limited | Process for chemical desulfurization of coal |
CN104675430A (en) * | 2015-03-04 | 2015-06-03 | 山西潞安环保能源开发股份有限公司 | High-hydrogen-sulfide coal seam roadway construction advanced alkali injection process and alkali liquid formula |
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