JPH06917B2 - Method for removing sulfur and ash from coal or other carbonaceous materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reducing the sulfur and ash content of coal or other carbonaceous material. In particular, the present invention can be used to produce pyrite sulfur (pyri) from coal or other carbonaceous materials.
tic sulfur), organic and elemental sulfur, and chlorination processes for extracting ash.

In the first example of the invention, most of the iron sulphide sulfur, organic sulfur and elemental sulfur can be removed in the form of sulphate sulfur. In the second example of the present invention, sulfur that can be recovered as elemental sulfur is first removed, and then most of the remaining sulfur is removed as sulfate sulfur. The present invention is particularly useful for removing organic sulfur from coal or other carbonaceous materials.

Coal desulfurization methods are well known in the art. While most of these methods are useful in reducing the iron sulfide ore sulfur content of coal, they have little or no effect in reducing organic or elemental sulfur in the coal.

One method was demonstrated in U.S. Pat. No. 3,960,513, which discloses a method for reducing the amount of sulfur in coal by subjecting an aqueous slurry of coal to a leaching process with pressurized oxygen. In one example, the aqueous slurry may be acidic. However, this treatment primarily removes the iron sulfide ore sulfur. Removal of organic sulfur requires the additional step of treating the coal with oxygen and a solvent such as ammonium hydroxide. Moreover, removal of elemental sulfur requires a separate extraction with a solvent such as kerosene or toluene.

Also, the removal of iron sulfide ore sulfur with an acid leachate or oxygen containing gas is disclosed in US Pat. No. 4,083,696.

Another method for removing iron sulfide ore from coal is U.S. Pat.
3,926,575 and 3,768,988.
In this method, milled coal is reacted with sulfuric acid and optionally hydrochloric acid to form ferric chloride, which probably reacts with the iron sulfide in the coal to form free sulfur. Furthermore, in order to remove free sulfur in coal,
In addition to acid leaching, a final solvent extraction step can be performed. Obviously, if the solvent is p-cresol, it is also possible to remove some of the organic sulfur compounds contained in the coal.

U.S. Pat. No. 4,305,726 relates to a method of removing iron sulfide sulfur and ash from coal. In this method, coal is treated with waste pickling liquor and reacted in the presence of hydrochloric acid, hypochlorous acid and oxygen gas produced by adding the coal / pickling liquor mixture to a reactor with water and chlorine gas. . After the reaction, the ash is removed by using mechanical means such as a weir.

In addition to the above desulfurization method, a method using a metal chloride salt is known. For example, U.S. Pat. No. 3,909,213 discloses digestion of coal with oxides of Group IA or IIA metals and molten metal chloride salts such as zinc chloride or ferric chloride.
gesting) coal desulfurization method is disclosed. It is clear that this medium can dissolve the sulfur-containing organic compounds present in coal. Pass anhydrous hydrogen chloride through the digestion zone. U.S. Pat. No. 4,127,390 discloses a method for extracting iron sulfide ore sulfur from coal using an aqueous sodium chloride solution.

In addition to the numerous examples of the various methods described above, the use of sulphates such as flammable sulfur solvents (U.S. Pat. No. 4,203,727) and chlorinated organic solvents (U.S. Pat. No. 4,081,250) produces organic sulfuric acid from coal. It is also known that salt can be extracted.

Despite the numerous coal desulfurization methods described above, there is clearly room for improvement. In particular, a more effective and economical desulfurization method for coal and other carbonaceous materials is desired.

Accordingly, it is a first object of the present invention to provide a method of removing sulfur and ash from coal and other carbonaceous materials which removes organic and elemental sulfur as well as iron sulfide ore.

Another object of the present invention is to provide a method of removing sulfur and ash from coal using readily available and inexpensive chemical components.

Another object of the present invention is a coal capable of removing a large amount of organic sulfur, sulfate sulfur and sulphide iron sulfur from coal in a short time without chlorinating the coal and without losing a large amount of coal during the treatment process. The purpose is to provide a method of removing sulfur and distributions from water.

Another object of the present invention is to provide a method of removing iron sulfide sulfur, organic sulfur, elemental sulfur and ash from raw coal.

Yet another object of the present invention is to provide a method of removing sulfur and ash from coal which removes ash in solution.

These and other objects are in the removal of sulfur and ash from coal or other carbonaceous materials containing iron sulfide sulfur, sulfides, elemental sulfur, organic sulfur and / or sulfate sulfur, (I) An aqueous slurry of the coal or other carbonaceous material,
At a temperature higher than the oxidation temperature of the coal or other carbonaceous material, in the presence of an oxidizing agent capable of solubilizing the iron sulfide ore sulfide, in the following composition (A) or composition (B) (1) at least one alkaline earth metal chloride, at least one alkaline metal chloride or a mixture of the chlorides, and (2) (a) ( i) containing one or more deliquescent halogen salts, barium chloride, potassium chloride or mixtures thereof, and (ii) one or more reducing oxides, one or more chromates or mixtures thereof, and (Iii) If potassium chloride is not present in the slurry containing the composition (A), a catalyst containing potassium fluoride or tannic acid; and (b) (i) hydrochloric acid, (ii) )
A treatment agent containing nitric acid, (iii) g hydrochloric acid and nitric acid, (iv) hydrochloric acid and ferric chloride, and (v) an inorganic acid selected from the group consisting of nitric acid and ferric chloride, (3) When iron is not present in the coal or other carbonaceous material, ferric chloride is allowed to be present in the sly containing the composition (A), and the composition (B) is 1) hypochlorite or a mixture of hypochlorites, and (2) (a) (i) one or more deliquescent halogen salts, barium chloride, potassium chloride or mixtures thereof, and (ii) one If potassium chloride is not present in the slurry containing (iii) the composition (B), containing the above reducing oxides, one or more chromates, or a mixture thereof, a fluorine oxide is added. A catalyst containing potassium iodide or tannic acid; and (b) (i) hydrochloric acid, A mixture of the catalyst (a) with one inorganic acid selected from the group consisting of ii) nitric acid, (iii) hydrochloric acid and nitric acid, (iv) hydrochloric acid and ferric chloride, and (v) nitric acid and ferric chloride. (3) When iron is not present in the coal or other carbonaceous material, the composition (B) is contained. Ferric chloride is present in the slurry, thereby converting substantially all of the sulfur extracted from the coal or other carbonaceous material to sulfate sulfur or other water soluble sulfur; (II) the coal or To provide a method for removing sulfur and ash from coal or other carbonaceous substances, characterized by separating other carbonaceous substances from a solution and (III) washing the separated coal or other carbonaceous substances. Achieved by

In another example, the present invention provides for the removal of sulfur and ash from coal or other carbonaceous materials containing iron sulfide sulfur, sulfides, elemental sulfur, organic sulfur and / or sulfate sulfur. An aqueous slurry of the coal or other carbonaceous material,
A composition comprising one or more alkaline earth metal chlorides, one or more alkali metal chlorides or a mixture of the chlorides and sulfuric acid at a temperature below the oxidation temperature of the coal or other carbonaceous material. If no iron is present in the coal or other carbonaceous material during the treatment, ferric chloride is also present, whereby most of the sulfur extracted from the coal or other carbonaceous material is present. (II) separating the coal or other carbonaceous material from the solution; (III) separating the coal or other carbonaceous material from the coal or other carbonaceous material; Stirring in an aqueous mixture containing the following composition (A) or composition (B) in the presence of an oxidizing agent capable of solubilizing the iron sulfide ore sulfide at an elevated temperature lower than the oxidation temperature, composition (A) is (1) one or more alkaline earth metal chlorides, one or more alkali metal chlorides or mixtures of said chlorides, and (2) (a) (i) hydrochloric acid, (ii) nitric acid. An inorganic acid selected from the group consisting of (iii) hydrochloric acid and nitric acid, (iv) hydrochloric acid and ferric chloride, and (v) nitric acid and ferric chloride, and (b)
(I) one or more deliquescent halogen salts, one selected from the group consisting of barium chloride, potassium chloride and mixtures thereof, and (ii) one or more reducing oxides,
Containing at least one chromate or a mixture thereof, and (iii) containing potassium fluoride or tannic acid when potassium chloride is not present in the slurry containing the composition (A). Containing a treating agent consisting of one selected from the group consisting of a mixture of the catalyst and the inorganic acid (a), and (3) iron is not present in the coal or other carbonaceous material. In this case, ferric chloride is present in the slurry containing the composition (A), and the composition (B) comprises (1) a hypochlorite salt or a hypochlorous acid mixture, and 2) (a) (i) one or more deliquescent halogen salts, barium chloride, potassium chloride or mixtures thereof, and (ii) one or more reducing oxides, one or more chromates or their A mixture, and (iii) the above composition When the potassium chloride is not present in said slurry containing (B), the catalyst was contained potassium fluoride or tannic acid; and (b) (i) hydrochloric acid, (ii)
1 selected from the group consisting of nitric acid, (iii) hydrochloric acid and nitric acid, (iv) hydrochloric acid and ferric chloride, and (v) nitric acid and ferric chloride
Contains a treating agent consisting of one selected from the group consisting of a mixture of one kind of inorganic acid and the catalyst (a), and (3) no iron is present in the coal or other carbonaceous material. In some cases, ferric chloride is present in the slurry containing the composition (B) such that almost all of the sulfur extracted from the coal or other carbonaceous material is sulfated sulfur or other sulfur. Conversion to water-soluble sulfur: (IV) re-separation of the coal or other carbonaceous material from the solution, (V) washing of the re-separated coal or other carbonaceous material, coal or other A method for removing sulfur coatings and ash from carbonaceous materials is provided.

The method of the present invention can desulfurize coal or other carbonaceous material and solubilize ash. Examples of other carbonaceous materials are lignite, peat, shale, sand and solid coal derivatives, and solid coal derivatives include bituminous coal, subbituminous coal and anthracite derivatives.

Here, "raw material coal" means coal from which only rock, dust and sand have been removed. Prior to treatment according to the present invention, the raw coal is washed to remove shale, dust and other gangue and has a standard ball mill feed size of about 1.87.
Grind to 5 to 1.25 mm (3/4 to 1/2 inch) negative size particles.

The particles are then fed into a ball mill and wet milled to approximately 100
Make ~ 300 mesh particles. It is desirable to mill the coal because it facilitates rapid interaction between the sulfur compounds contained in the coal matrix and the components in the extraction mixture.

If necessary, the finely pulverized coal is floated and settled (sink floa
can be combined with the extraction mixture after ting).
The flotation process uses hydrocarbon solvents and other chemicals to remove heavy sulfur-rich particles from comminuted coal.

Here, the "extraction mixture" means the following components according to the present invention: 1
One or more alkaline earth metal salts or alkali metal salts or mixtures thereof, one or more hypochlorite salts; one or more inorganic acids; one or more catalysts or catalyst components; an oxidizer; oxygen, acid enrichment Mean air, or air; and an aqueous solution containing ferric chloride, either separately or in combination.

Further, unless otherwise stated, all concentrated hydrochloric acid solutions are reagent grade concentrated hydrochloric acid, ie, about 38 wt% hydrochloric acid; all concentrated nitric acid solutions are about 68 wt% nitric acid; all concentrated ferric chloride solutions are
30 wt% solution; all concentrated sulfuric acid solutions are about 98 wt% sulfuric acid; concentrated acetic acid solutions are all about 100 wt% acetic acid. All concentrated acid solutions are commercially available reagent grade concentrated solutions unless otherwise noted.

In one example of the present invention, iron sulfide sulfur, sulfides, elemental sulfur,
Coal or other carbonaceous material containing organosulfur and / or sulphate sulfur, one or more alkaline earth metal chlorides, one or more alkali metal chlorides or mixtures of such chlorides and catalysts and inorganic acids. Treated in the presence of an oxidizer capable of solubilizing iron sulfide ore sulfides at high temperatures with a treating agent containing and without the presence of iron in coal or other carbonaceous material Ferric chloride is optionally present in the aqueous slurry containing the extraction mixture. Alternatively, the aqueous slurry solubilizes the iron sulfide ore sulfide at elevated temperature with a composition containing hypochlorite or a mixture of hypochlorite and a catalyst or a mixture of a catalyst and an inorganic acid. In the presence of an oxidizing agent capable of producing ferric chloride in the aqueous slurry containing the extraction mixture in the absence of iron in coal or other carbonaceous material. . In this example, sulfur is removed as sulfate or other water soluble sulfur.

Of the alkaline earth metal chlorides such as barium chloride, magnesium chloride and calcium chloride, calcium chloride is preferred. Of the alkali metal chlorides, sodium chloride, potassium chloride and mixtures thereof are preferred.

Alkaline earth metal chlorides and / or alkali metal chlorides are used in amounts of about 7 to 8 chlorine molecules for each sulfur atom contained in the coal.

The catalyst according to the invention contains one or more deliquescent halogens, barium chloride, potassium chloride or mixtures thereof, and one or more reducing oxidants, one or more chromates or mixtures thereof, If potassium chloride is not present in the aqueous slurry containing the extraction mixture, potassium fluoride or tannic acid is also included in the catalyst.

Examples of deliquescent halogen salts that are particularly useful in the present invention are calcium chloride, magnesium chloride and mixtures thereof.

Examples of reducing oxides are chromic oxide, manganese dioxide and iron (III) oxide.

Examples of chromates are potassium dichromate and sodium chromate.

The catalyst components are usually present in the following quantities: deliquescent halogen salts, barium chloride, potassium chloride or mixtures thereof (about 90 to 95% by weight of the catalyst mixture); reducing oxides, chromates or These mixtures (about 6-10% by weight of the catalyst mixture); potassium fluoride or tannic acid, if present (about 3-5% by weight of the catalyst mixture).

A particularly preferred catalyst composition comprises calcium chloride, magnesium chloride and / or potassium chloride in an amount of about 90 to 95% by weight, based on the total weight of the catalyst mixture; chromic oxide or chromate in an amount of about 3 to 5%. % Manganese dioxide in an amount of about 3-5% by weight; potassium fluoride in an amount of about 3-5% by weight in the absence of potassium chloride in the aqueous slurry containing the extraction mixture. Contained in.

Examples of suitable catalyst compositions are disclosed in U.S. Pat. Nos. 2,369,024 and 2,089,599 (incorporated herein by reference), but examples of amounts are not necessarily disclosed. These U.S. patents teach spraying the catalytic component onto the coal prior to combustion, thereby increasing the concentration of sulfur dioxide from the iron sulfide ore during combustion of the coal. Therefore, it is quite unexpected that such catalyst components would be useful in desulfurizing these materials in aqueous slurries of coal or other carbonaceous materials, especially because the desulfurization process of the present invention involves sulfur dioxide emissions. This is because the concentration is decreased rather than increased.

The catalyst is used in an amount of about 1-10% by weight of total sulfur in the solid, ie coal or other carbonaceous material, preferably in an amount of about 2-10% by weight of total sulfur in the solid. The total amount of sulfur present in the solid can be measured using conventional chemical analysis methods.

As the inorganic acid, hydrochloric acid, nitric acid, hydrochloric acid and nitric acid, hydrochloric acid and ferric chloride, or nitric acid and ferric chloride can be used. Mixtures of nitric acid and hydrochloric acid with ferric chloride are preferred.

The amount of acid used is that amount needed to raise the pH of the initial solution to about 2-5.

In addition, ferric chloride must be present in the aqueous slurry containing the extraction mixture if iron is not present in the coal or other carbonaceous material. The ferric chloride can be added as it is or generated in the system. The amount of iron depends on the coal or other carbonaceous material being processed 10
About 0.5-3.0 bond per pound (about 0.5-3.0k per 100kg)
A ratio of g) is suitable.

In another example, calcium hypochlorite or sodium hypochlorite, preferably sodium hypochlorite, can be used as the hypochlorite.

Hypochlorite is used in an amount of about 100 grams of hypochlorite for 400 grams of water and 200 grams of coal or other carbonaceous material.

Moreover, in other examples using hypochlorite, the catalyst is the same as described above. The amount of catalyst used is about 1 to 10% by weight of the total flow yellow in the solid, preferably about 2 to 10% by weight of the total sulfur in the solid. When an inorganic acid is used with the catalyst, the inorganic acid is used in a quantity of about 1 to 5% by volume acid solution, based on the final volume of the aqueous slurry containing the extraction mixture.

In the absence of iron in the coal or other carbonaceous material, as in the example above, ferric chloride will be present at about 0.5-3.0 per 100 pounds of coal or other carbonaceous material treated.
It should be present in the extraction mixture at a rate of about one pound (about 0.5 to 3.0 kg per 100 kg).

The above composition comprising metal chloride, catalyst and acid or hypochlorite and catalyst (or catalyst and acid) is contacted with coal or other carbonaceous material for about 10 to 45 minutes, preferably about 30 minutes, Along with this, an oxidant capable of solubilizing the iron sulfide ore sulfide, such as oxygen gas, sulfur dioxide gas, oxygen-enriched air, sulfur dioxide-enriched air, or air is added. A suitable amount of the above oxidizer is about 1-5 /
Minutes, preferably about 1-2 minutes. Coal or other carbonaceous material is agitated with the extraction mixture at an elevated temperature below the oxidation temperature of the coal or other carbonaceous material. A suitable temperature range is about 80-130 ° C. Further, it is preferable that the stirring is performed at about atmospheric pressure. However, if carbonaceous material degradation does not occur, the pressure will range from approximately atmospheric pressure to 500 psi (3
The range can be 5.15 kg / cm ² ) or more.

If stirring is performed at about atmospheric pressure, the temperature is about 85 to 90.
It is preferably in ° C.

Further, in the present invention, the time when the coal or other carbonaceous material is treated with the above composition can be changed as follows: (1) Wet grinding of coal or other carbonaceous material before It can be transferred to two reaction zones where the finely divided material is present in the presence of alkaline earth metal chlorides and / or alkali metal chlorides and catalysts and acids or hypochlorite and catalysts (or catalysts and acids). (2) Coal or other carbonaceous material is wet-milled in the presence of an alkaline earth metal chloride and / or an alkali metal chloride or hypochlorite, and then this slurry is stirred. The agitation is transferred to a reactor, where the slurry is heated and reacted in the presence of a catalyst and an acid or a catalyst (or a catalyst and an acid); It can be achieved at the same time in the presence of a metal chloride and / or alkali metal chloride and a catalyst and an acid or hypochlorite and the catalyst (or catalyst and acid). The oxidizing agent is added in the heating reaction step. When ferric chloride is added to the extraction mixture, it is preferable to add ferric chloride in the heating reaction step, but it can also be added in the wet grinding step.

Of the above three examples, the second and third examples are preferred,
The reason for this is that milling coal or other carbonaceous materials in a mixture significantly increases the amount of sulfur removed from the coal. This is because the catalytic action of the acid and the exotherm in the grinding zone act to release sulfur by the addition of some sulphide.

By carrying out the method described above, all types of sulfur present in the coal become water-soluble and are easily removed by hot water washing, hot dilute acid washing or hot alkaline solution washing. Hot dilute acid washing or hot alkaline solution washing is preferred.

In the present invention, the dilute acid washing can be performed with any inorganic acid or organic acid. Examples of suitable inorganic acids are nitric acid, sulfuric acid and hydrochloric acid. Examples of suitable organic acids are balacetic acid and acetic acid. The preferred acids are nitric acid and sulfuric acid. Nitric acid is particularly preferred. Nitric acid strongly oxidizes the sulfur thin film occluded in solid matter even in dilute iron solution, completely dissolves sulfide that causes failure during processing, and some organic matter remaining in a dissolved state. Helps remove material.

A suitable acid concentration is a concentrated acid solution of about 5-10% by volume, based on the final volume of the wash liquor.

Suitable alkaline wash solutions are about 0.1 to 3 molar solutions of ammonium hydroxide, sodium hydroxide or potassium hydroxide. A solution of about 0.1 to 0.2 molar is preferred. However, the concentration of the alkaline solution is limited by the time when the volatile substance or the soluble carbon compound begins to decompose, and can be easily determined by those skilled in the art.

Cleaning temperature with water, dilute acid or alkaline solution is about 90 ~
100 ° C, preferably just below the boiling point at atmospheric pressure. Washing is performed for a time that can be easily determined by those skilled in the art. A suitable time is about 5 to 30 minutes, preferably about 15 minutes.

Although the above-described process of contacting finely ground coal with an alkaline earth metal and / or alkali metal salt, catalyst and acid or hypochlorite and catalyst (or catalyst and acid) removes large amounts of sulfur compounds from the coal. ; Cleansing coal by dilute acid cleaning or hot alkaline solution cleaning to obtain E
PA coal combustion standard, ie 1,000,000 BTU (556,000
SO ₂ emissions per kcal / kg) 1.2 lbs (544 g)
Sulfur reduction sufficient to meet

In a second example of the invention, an aqueous slurry of coal or other carbonaceous material is subjected to oxidation of the coal or other carbonaceous material prior to removing the sulfur in the form of sulfate or other water soluble sulfur. Treated with a composition containing one or more alkaline earth metal chlorides and / or alkali metal chlorides or mixtures thereof and nitric acid at a temperature below the temperature, wherein iron in coal or other carbonaceous material The presence of ferric chloride in the aqueous slurry containing the extraction mixture, in the absence of any, to remove almost all of the sulfur extracted from the coal or other carbonaceous material as elemental sulfur. The steps are performed.

Suitable alkaline earth metal chlorides are the alkaline earth metal chlorides mentioned above, with calcium chloride being preferred. Suitable alkali metal chlorides are, for example, sodium chloride and potassium chloride. A mixture of sodium chloride and potassium chloride is preferred, and an equal weight mixture of sodium chloride and potassium chloride is particularly preferred.

The alkaline earth metal chloride and / or the alkali metal chloride can be added as an aqueous solution having a concentration of about 0.5 to 15% by weight. Aqueous solutions with a concentration of about 15% by weight are preferred.

The nitric acid provides a concentrated acid solution in the range of about 0.5-10% by volume, based on the final volume of the aqueous slurry, depending on the amount of total sulfur in the coal or other carbonaceous material. The particular amount of nitric acid within the usable range can be readily determined by those skilled in the art by monitoring sulfur removal.

The coal or other carbonaceous material is reacted with the above components at a temperature below the oxidation temperature of the coal or other carbonaceous material. A suitable temperature is about 80-130 ° C.

The reaction pressure may be in the range of atmospheric pressure to 500 psi (35.15 kg / cm ² ) or more if the carbonaceous material is not degraded. However, near atmospheric pressure is preferred.

If the reaction is carried out at atmospheric pressure, the mixture is preferably about 85
The reaction is carried out at a temperature of 130 ° C, particularly preferably 85 ° C to 90 ° C.

It is carried out for about 10 to 30 minutes, preferably for about 15 minutes, without the addition of reactive oxygen, oxygen-enriched air or air.

The reaction can also be carried out in the presence of added oxygen, oxygen-enriched air, or air in an amount of about 1-2 minutes / minute for about 15-30 minutes. Oxygen, oxygen-enriched air or air is used in the presence of nitric acid.

As in the first example, when ferric chloride is added to the reaction mixture, the rate of about 0.5 to 3.0 pounds per 100 pounds of coal treating ferric chloride (about 0.5 to 30 kg per 100 kg). Used in.

After the reaction, the solids can be separated from the liquid and the elemental sulfur can be recovered from the liquid by known means, for example using a sulfur precipitant. An example of a suitable sulfur precipitant is sodium citrate (United States
Bureau of Mines) Research Report-1980, R
W.A. Marchiant (W.
A. Marchant)) and acidic solutions, such as aqueous hydrochloric acid. Since chlorine is in a circuit with sulfur, elemental sulfur can also be precipitated with hydrogen iodide or an aqueous solution of hydrogen iodide, ie an aqueous solution of hydroiodic acid (HI). Perhaps as much as 85% of sulfur can be recovered in this intermediate step.

This intermediate treatment of recovering elemental sulfur can be carried out just as in the case of recovering sulfates and other soluble sulfur in three examples. That is, the following combinations are possible: (1) Coal or other carbonaceous material may be wet ground and then heat reacted in the presence of alkaline earth metal chlorides and / or alkali metal chlorides and nitric acid. Yes; (2) Coal or other carbonaceous material can be wet ground in the presence of alkaline earth metal chlorides and / or alkali metal chlorides and the solution heated and reacted with nitric acid. (3) Wet grinding and heating reaction can be carried out simultaneously in the presence of alkaline earth metal chloride and / or alkali metal chloride and nitric acid. Similar to the case of the first example, when ferric chloride is added to the extraction mixture, it is preferable to add ferric chloride in the heating reaction step, but it can also be added in the stirring step.

The solid separated from the extraction mixture is preferably washed with hot water, hot dilute acid solution or hot alkaline solution as described above. Hot acid solutions or hot alkaline solutions are preferred, with hot acid solutions being particularly preferred.

After carrying out the intermediate step, the solid is treated with a fresh solution containing alkaline earth metal chloride and / or alkali metal chloride and an inorganic acid or (a) alkaline earth metal chloride and / or alkali metal chloride and At a temperature below the oxidation temperature of coal or other carbonaceous material, with a solution containing one of the above compositions consisting of an acid and a catalyst or (b) a hypozinc salt and a catalyst (or a catalyst and an acid), In the presence of an oxidant capable of solubilizing the iron sulphide sulfur, for example oxygen gas, sulfur dioxide gas, oxygen-enriched air, sulfur dioxide-enriched air or air, again agitating as described above to further sulfur. It is removed as sulfate and then the coal is finally washed with hot water, hot dilute acid solution or hot alkaline solution and burned. If iron is not present in the coal or other carbonaceous material, ferric chloride should be present in the same amount as above when re-stirring with the extraction mixture.

Alkaline earth metal chlorides and / or alkali metal chlorides treat coal or other carbonaceous materials when the solids are re-stirred with alkaline earth metal chlorides and / or alkali metal chlorides and inorganic acids. Then, it can be the same as that described in the second example in which sulfur is extracted as elemental sulfur. The inorganic acid can be the same as that described in the first example of treating coal or other carbonaceous material to extract sulfur as sulfate or other water-soluble sulfur. However, sulfuric acid is preferred.

The alkaline earth metal chloride and / or the alkali metal chloride is in a final concentration of about 0.5-5% by weight, preferably about 0.5-.
Used in a final concentration of 2% by weight.

The acid is about 1.25-5% based on the final aqueous volume, preferably about 1.
Use in a concentrated solution volume of 25-3%.

The oxidant amount, temperature and pressure conditions, and time parameters are the same as those described in the first example of extracting sulfur as sulfate or other water-soluble sulfur. After stirring again, the separated solid is washed with hot water, hot dilute acid solution or hot alkaline solution as described above for the first example.

As an additional step desirable in all of the above examples:
A final wash with a dilute solution of potassium chromate or potassium fluoride can be performed to reduce corrosion and slag formation during coal combustion. This is not an essential step, but a preferred step. A suitable amount of potassium chromate or potassium fluoride is 1% by weight.

As mentioned above, comminuting the solid facilitates a rapid and complete reaction between the sulfur impurities in the solid and the chemicals in the extraction mixture. The reaction of the solids with the extraction mixture is an exothermic reaction, raising the temperature of the extraction mixture slurry from ambient temperature to as high as 50 ° C. Thus, the only additional heating required while maintaining the extraction mixture and comminuted coal in contact is the amount of heat that raises the temperature of the extraction mixture slurry from about 50 ° C to about 80 ° C.

Also, it is desirable to include an emulsifier in the extraction mixture slurry to increase the efficiency of the process because the rapid, near-instantaneous reaction between the solids and the chemicals in the extraction mixture causes vigorous foaming. A suitable commercially available emulsifier useful in the present invention is DB-110A (trade name), a nonionic emulsifier manufactured by Dow Corning. As the emulsifier, a 2% emulsifier solution is used in an amount of 2 to 5 g based on 1 of the aqueous coal slurry.

Coal and extraction mixture are put together in a closed reaction vessel, agitated to maintain the exotherm of the exothermic chemical reaction that takes place and to reduce the amount of chemicals that escape into the air while agitating the extraction mixture slurry. Is preferred. Since it is common to consume only a portion of each chemical component in the extraction mixture during the processing of a given amount of coal, the extraction mixture is separated from the desulfurized treated coal to obtain the required amount of each extraction chemical. It can be replenished and then recycled to treat another portion of solids. The extraction mixture solution is periodically processed to remove sulfur or sulfate and then replenished or recycled or simply discarded. When the coal and extraction mixture are agitated in a closed reaction vessel, the reaction chemistry is maintained, reducing the amount of new chemical that needs to be added to the recycle extraction mixture.

Sulfates and other soluble sulfur compounds are removed from the spent mixture solution by known means such as precipitation with calcium salts or barium chloride.

When the milled coal and extraction mixture are first combined, the pH of the extraction mixture solution and the liquid components are about 2-5. Contacting the extraction mixture solution with the solid for about 15 minutes brings the pH of the solution to about 0.1. After separating the comminuted solids from the extraction mixture solution by conventional means, the solids are washed with hot water, hot alkaline solution or dilute acid solution as described above. Washing with water, alkaline solution or acid removes soluble sulfur compounds and sulphates along with organic sulfur compounds adhering to the solids while separating the solids from the extraction mixture. The washed solids are dried using any conventional means, for example under vacuum or using steam, to remove any moisture or occluded acid carried by the solids. Since the solids are finely ground, care must be taken not to expose the solids to the oxygen source while the solids are at high temperature.

Washed and dried coal can be directly fed to a boiler for combustion, can be transferred to other plants by slurry and pi brine, or can be pelletized or briquetted for shipping, storage and subsequent sale and use be able to.

Although the present invention has been described as a continuous process, an improved batch process, a semi-continuous process, can also be used.

The invention will now be described with reference to the drawings for an integrated overall process for producing refined coal with on-site sulfur removal in open pit or land value coal mining operations.

FIG. 1 shows a first example of the process according to the invention, in which all extracted sulfur is extracted as sulphates or other soluble sulfur compounds. In the wet crushing device 2, the crushed raw coal 1 is mixed with water 3 and salts 4 of potassium chloride and sodium chloride 4.
And wet pulverize together. Then, the crushed coal slurry 5 is heated in the heating reactor 6 to be supplied with oxygen gas or air 7,
Stir while adding sulfuric acid 8 and catalyst 9 to produce sulfate and other soluble sulfur compounds. The coal can be agitated in the heated reactor at any desired pressure. The temperature of the mixture in the heated reactor can be increased by supplying heat, which is a byproduct of the plant that produces the components used in the process. After stirring for about 15 minutes, the reacted coal slurry 10 is separated into a liquid component 16 and a solid component 12 by a coal / liquid separator 11. Solid component
Desulfurized coal 14 is obtained by washing 12 with a washing device 13 using hot water, dilute acid or alkaline solution. The cleaning liquid can be recirculated as the recirculation cleaning liquid 15.

A sulfate or other water-soluble sulfur 19 is regularly recovered from the liquid component 16 from the coal / liquid separation process by the sulfate recovery device 17. The liquid 16 or 18 can be recycled and agitated for use in the heated reactor 6. If the extraction mixture is recycled, fresh chemicals are added to bring the strength of each chemical in solution to an acceptable level within the above range.

FIG. 2 shows a second example of the method according to the invention, in which elemental sulfur is recovered during the extraction process. The pulverized raw coal 1 is wet pulverized by a wet pulverizer 2 in the presence of sodium chloride and potassium chloride salts 20 and water 3. Then, the crushed coal slurry 5 is heated in a heating reactor 21 to remove sulfuric acid 22
Stir in the presence of. Reacted coal slurry 23
A liquid separator 24 separates a solid component 25 and a sulfur-containing liquid component 26. The coal solid 25 is washed with a washing device 31 using hot water, dilute acid or alkaline solution, and the washed coal solid 32 is charged with sodium chloride and potassium chloride salt 4 and nitric acid 8 in the second heating reactor 6. And agitate again in the presence of oxygen gas or air 7. Next, the reacted coal slurry 10 is treated in the same post-treatment step as shown in FIG.

In order to recover elemental sulfur in the elemental sulfur recovery device 27, a sulfur precipitant 28 is contacted with the sulfur-containing liquid 26 to produce elemental sulfur 29. The elemental sulfur-depleted liquid 30 can be recycled to the agitated heating reactor 6 which is particularly desirable when recovering elemental sulfur using an acid process.

According to the present invention, the conventional method is significantly improved. In practicing the present invention, the processing facility is preferably located near or adjacent to the power plant. Power plants provide sources of cheap energy and water that are currently being wasted, especially those used in the cooling towers of most large power plants. In many cases such water may contain chemicals available in practicing the process of the invention, especially chromates or chromium,
Such chemicals are added to the cooling tower to prevent the formation of scale and are lost if there is no equipment to recover the metal from the cooling water. Cooling water may contain about 800 ppm of chromate. Such chromates can be utilized in the method of the present invention.

In addition, since natural brackish water or seawater or many of the components of the extraction mixture according to the present invention are contained, natural brackish water or seawater can be used in the extraction mixture. And especially when placed near seawater.

Clearly, in view of the present invention, it is necessary to locate the coal desulfurization plant near the combustion plant. By doing so, harmful production can be utilized to reduce processing costs and pollution sources. This substance is NO
x or nitric oxide. Nitrogen oxides separated from the exhaust gas stream of the coal by several known means, for example magnet hydrodynamics, can be added to nitric acid and used with the extraction mixture according to the invention.

The present invention will be described with reference to the following examples.

Example 1 A sample obtained by crushing Ohio # 6 raw coal to 100 mesh was analyzed. The results are shown in Table A. All parts, percentages, ratios, etc., are by weight unless otherwise indicated.

Grinding and Extraction 200 g of Ohio # 6 charcoal described above was ground to 100 mesh, then 1000 ml of water in a stirring reactor, 15 g of a mixture of NaCl and KCl, concentrated hydrochloric acid, ie about 37% wt / wt hydrochloric acid 15 ml,
Ferric chloride (30% wt / wt solution) 10 ml), and 90% M
Stir for 30 minutes at 85-90 ° C. in the presence of 5 g of a catalyst consisting of gCl, 5% manganese dioxide and 5% chromic oxide. The 15 wt% salt mixture of the solution was 7.5% NaCl and 7.5% KCl.

The coal recovered from the extraction mixture was washed with hot dilute sulfuric acid (50 ml of 69-71% nitric acid per 1000 ml of solution) for 15 minutes while stirring.

The coal was then separated from the wash liquor and the coal was analyzed to determine the sulfur content. The results are shown in Table B below.

The results show a reduction in total sulfur of about 76% on both the treated and dry basis.

Examples 2-3 A sample of washed, or floated, Ohio # 6 charcoal was analyzed. The results are shown in Table C below.

Grinding and Extraction Sample 1A 200 g of the Ohio # 6 float-sink treated carbon described above was mixed with 600 ml of water and N
aCl 15 g, concentrated hydrochloric acid or about 37% wt / wt hydrochloric acid 15 ml, and 90% calcium chloride and 5% chromic oxide and 5
% Wt / wt solution of catalyst consisting of 1% manganese dioxide 1
Heated for 30 minutes at a temperature of 80-85 ° C. with stirring in the presence of 0 ml. Air was bubbled through the solution at a flow rate of 1 / min.

The separated coal was analyzed for sulfur content and the results are shown in Table D.

The results show that about 60% of the sulfur was removed on a treated state basis and about 67% of the sulfur was removed on a dry basis.

Sample 1B 200 g of the above Ohio # 6 washed charcoal (Table C) crushed to 100 mesh, 800 ml of water, 15 g of NaCl, 20 ml of concentrated hydrochloric acid or about 37% wt / wt hydrochloric acid and 45% MgCl, 45% CaCl and 5% 80-85 in the presence of 5 ml of a 100% wt / wt solution of a catalyst consisting of MgO ₂ and 5% chromic oxide.
The reaction was carried out at 30 ° C for 30 minutes. Air was bubbled through the solution at a flow rate of 1 / min.

The separated coal was analyzed for sulfur content and the results are shown in Table E below.

The results show that about 40% of the sulfur was removed on a treated state basis and about 48% of the sulfur was removed on a dry basis.

Example 4 500 ml of water, 15 g of a mixture of NaCl / KCl (50 parts by weight / 50 parts by weight) while stirring 100 g of the above-mentioned Ohio # 6 washed carbon (Table C) crushed into 100 mesh, without adding air or oxygen. , And 10% nitric acid (prepared by mixing 10 parts by volume of 69 to 71% nitric acid with 90 parts by volume of water) 500 ml
And reacted at about 90 ° C for 30 minutes. Filter this slurry,
The coal was washed with 500 ml of 10% nitric acid (prepared as above). The separated pickled carbon was analyzed for sulfur content and the results are shown in Table F below.

The results show that about 65% of the sulfur was removed on a treated state basis and about 70% of the sulfur was removed on a dry basis.

Example 5 A sample of Ohio # 6 feed coal (Table A) was prepared as in Example 1 above.
In the same manner as in (1) and (2), the coal recovered from the extraction mixture was subjected to various cleaning treatments to determine the nature and amount of sulfur,
Total solids at 180 ° C, non-volatile solids at 550 ° C and iron removed were measured. The results are shown in Table G below.

The pickling solution is a cleaning solution when washed with 10% nitric acid (prepared by mixing 10 parts by volume of 69 to 71% nitric acid and 90 parts by volume of water) at about 85 ° C. for 15 minutes. Analysis of the spent acid wash liquor shows that sulfur is washed from the coal in a soluble form and that ash is entrained in the wash liquor. A small amount of volatile material was removed. This is organic sulfur.

The water washing solution is a washing solution when the acid-washed coal is washed with water at about 85 ° C for 15 minutes. Analysis of the wastewater wash liquor shows that only a small amount of occluded solid matter, including sulfur and ash, remains in the coal in the acid wash liquor, which removes the occluded solid liquor that the acid wash liquor remains after extraction. It is very effective for teaching.

The 2.4% alkaline solution cleaning solution is about 85% extracted coal.
This is a cleaning solution when it is cleaned with 2.4% ammonium hydroxide at ℃ for 15 minutes. The analytical results of the waste 2.4% alkaline solution wash show that this alkaline solution wash is superior to the acid wash in terms of sulfur and ash removal. However, the alkaline solution wash removed more total solids than the acid wash. This indicates that a larger amount of volatiles is removed, which is accompanied by a decrease in the total calorific value of coal.

5% alkaline solution cleaning solution is about 85 ℃ for extracted coal.
This is a cleaning liquid when it is washed with 5% ammonium hydroxide for 15 minutes. The analysis result of the waste 5% alkaline solution cleaning solution is
It shows that extraction of very high amounts of sulfur, ash, and total solids has occurred. The large amount of total solids removed is due to the removal of volatile substances, which shows that the total calorific value of coal decreases accordingly.

A special sample is the extract after 10 minutes of extraction. Analysis of the extract shows that at least some of the sulfur has already been removed after reaction with the extraction mixture for only 10 minutes.

[Brief description of drawings]

FIG. 1 is a flow sheet of one example of the method of the present invention, and FIG. 2 is a flow sheet of another example of the method of the present invention. DESCRIPTION OF SYMBOLS 1 ... Crushed raw material coal 2 ... Wet grinding apparatus 3 ... Water 4 ... Potassium chloride and sodium chloride salt 5 ... Crushed coal slurry 6 ... Heating reactor 7 ... Oxygen gas or air 8 ... Nitric acid 9 ... Catalyst 10 ... Reacted coal slurry 11 ... Coal / liquid separation device 12 ... Solid component 13 ... Cleaning device using hot water, dilute acid or alkaline solution 14 ... Desulfurized coal 15 ... Recycled cleaning liquid 16 ... Liquid component (liquid) 17 ... Sulfate Recovery device 18… Recycled extraction mixture (liquid) 19… Sulfate or other water-soluble sulfur 20… Potassium chloride and sodium chloride salts 21… Heating reactor 22… Nitric acid 23… Reacted coal slurry 24… Coal / liquid separation Device 25 ... Solid component (coal solids) 26 ... Sulfur-containing liquid component (sulfur-containing liquid) 27 ... Elemental sulfur recovery device 28 ... Sulfur precipitant 29 ... Elemental sulfur 30 ... Liquid from which elemental sulfur is removed (recirculation liquid) 31 … Hot water, dilute acid Cleaning device 32 ... washed coal solids using an alkaline solution.

Claims (10)

[Claims] 1. Removal of sulfur and ash from coal or other carbonaceous material containing iron sulphide sulfur, sulfide, elemental sulfur, organic sulfur and / or sulphate sulfur, (I) said coal or other Of carbonaceous material aqueous slurry of
At a temperature higher than the oxidation temperature of the coal or other carbonaceous material, in the presence of an oxidizing agent capable of solubilizing the iron sulfide ore sulfide, in the following composition (A) or composition (B) And wherein the composition (A) comprises (1) one or more alkaline earth metal chlorides, one or more alkali metal chlorides or a mixture of the chlorides; and (2) (a) ( i) containing one or more deliquescent halogen salts, barium chloride, potassium chloride or mixtures thereof, and (ii) one or more reducing oxides, one or more chromates or mixtures thereof. And (iii) potassium fluoride in the slurry containing the composition (A), if potassium chloride is not present; and (b) (i) hydrochloric acid, (Ii)
Nitric acid, (iii) hydrochloric acid and nitric acid, (iv) hydrochloric acid and ferric chloride,
And (v) containing a treating agent containing an inorganic acid selected from the group consisting of nitric acid and ferric chloride, (3) when iron is not present in the coal or other carbonaceous material, Ferric chloride is present in the slurry containing the composition (A), and the composition (B) comprises (1) a hypochlorite salt or a hypochlorite mixture, and (2) ( a) containing (i) one or more deliquescent halogen salts, barium chloride, potassium chloride or mixtures thereof, and (ii) one or more reducing oxides, one or more chromates or mixtures thereof. And (iii) when potassium chloride is not present in the slurry containing the composition (B), a catalyst containing potassium fluoride or tannic acid; and (b) (i) hydrochloric acid, (Ii) nitric acid, (iii) hydrochloric acid and nitric acid, (iv) hydrochloric acid and chloride Containing a treating agent consisting of diiron and (v) one inorganic acid selected from the group consisting of nitric acid and ferric chloride and one selected from the group consisting of a mixture of the catalyst (a), (3) When iron is not present in the coal or other carbonaceous material, ferric chloride is allowed to be present in the slurry containing the composition (B), whereby the coal or other Converting almost all of the sulfur extracted from the carbonaceous material of claim 1 into sulfate sulfur or other water-soluble sulfur; (II) separating said coal or other carbonaceous material from solution; (III) separating the coal or A method for removing sulfur and ash from coal or other carbonaceous materials, characterized by cleaning other carbonaceous materials. 2. The treatment step (I) comprises the substeps of (I ') wet-milling the coal or other carbonaceous material; followed by at the same time (I ") the coal or other carbonaceous material. Patent comprising the step of stirring the aqueous mixture of substep (I ') with the composition (A) or the composition (B) in the presence of the oxidizing agent at a temperature lower than the oxidation temperature of the carbonaceous material. The method according to claim 1. 3. A step (I) of treating with the composition (A).
(I ') wet-milling the coal or other carbonaceous material in the presence of the one or more alkaline earth metal chlorides, the one or more alkali metal chlorides, or a mixture thereof. And (I ″) treating the composition (A) with the aqueous mixture of substep (I ′) in the presence of the oxidant at an elevated temperature below the oxidation temperature of the coal or other carbonaceous material. A method as claimed in claim 1 comprising the following substeps of stirring. 4. A step (I) of treating with the composition (B) comprises: (I ') wet-milling the coal or other carbonaceous material in the presence of the hypochlorite or a mixture thereof. And (I ″) treating the composition (B) with the aqueous mixture of substep (I ′) in the presence of the oxidant at an elevated temperature below the oxidation temperature of the coal or other carbonaceous material. A method as claimed in claim 1 comprising the following substeps of stirring. 5. Removal of sulfur and ash from coal or other carbonaceous materials containing iron sulphide, sulfides, elemental sulfur, organic sulfur and / or sulphate sulfur, (I) said coal or other Of carbonaceous material aqueous slurry of
Treated with a composition containing one or more alkaline earth metal chlorides, one or more alkali metal chlorides or a mixture of said chlorides and nitric acid at an elevated temperature below the oxidation temperature of said coal or other carbonaceous material. However, at this time, when iron is not present in the coal or other carbonaceous material, ferric chloride is also present, whereby almost all of the sulfur extracted from the coal or other carbonaceous material is present. (II) separating the coal or other carbonaceous material from the solution; (III) separating the separated coal or other carbonaceous material from the solution of the coal or other carbonaceous material; Stirring in an aqueous mixture containing the following composition (A) or composition (B) in the presence of an oxidizer capable of solubilizing the iron sulfide ore sulfide at an elevated temperature below the temperature, The product (A) is (1) one or more alkaline earth metal chlorides, one or more alkali metal chlorides or a mixture of said chlorides, and (2) (a) (i) hydrochloric acid, (ii) An inorganic acid selected from the group consisting of nitric acid, (iii) hydrochloric acid and nitric acid, (iv) hydrochloric acid and ferric chloride, and (v) nitric acid and ferric chloride, and (b)
(I) one or more deliquescent halogen salts, one selected from the group consisting of barium chloride, potassium chloride and mixtures thereof, and (ii) one or more reducing oxides,
Containing at least one chromate or a mixture thereof, and (iii) containing potassium fluoride or tannic acid when potassium chloride is not present in the slurry containing the composition (A). Containing a treating agent containing one selected from the group consisting of a mixture of the catalyst and the inorganic acid (a), and (3) iron is present in the coal or other carbonaceous material. If not, ferric chloride is present in the slurry containing the composition (A), and the composition (B) comprises: (1) a hypochlorite or a hypochlorite mixture, and (2) (a) (i) one or more deliquescent halogen salts, barium chloride, potassium chloride or mixtures thereof, and
(Ii) potassium chloride is present in the slurry containing one or more reducing oxides, one or more chromates or mixtures thereof, and (iii) the composition (B). If not, a catalyst containing potassium fluoride or tannic acid; and (b) (i) hydrochloric acid, (ii) nitric acid, (iii) hydrochloric acid and nitric acid, (iv) hydrochloric acid and ferric chloride and (v). (3) contains a treating agent consisting of one kind of inorganic acid selected from the group consisting of nitric acid and ferric chloride and one kind selected from the group consisting of a mixture of the catalyst (a); If iron is not present in the other carbonaceous material, ferric chloride is present in the slurry containing the composition (B), thereby extracting from the coal or other carbonaceous material. Almost all of the sulfur generated is sulfated sulfur or other water-soluble sulfur. (IV) The coal or other carbonaceous material is separated again from the solution, and (V) the coal or other carbonaceous material separated again is washed. Of removing sulfur and ash from wood. 6. A sub-step wherein said treatment step (I) comprises: (I ') wet-milling said coal or other carbonaceous material; and subsequently or simultaneously therewith (I ") said coal or other carbonaceous material. The aqueous mixture of substep (I ′) is combined with the one or more alkaline earth metal chlorides, the one or more alkali metal chlorides or a mixture of the chlorides and nitric acid at an elevated temperature below the oxidation temperature of the material. A method according to claim 5 comprising the substeps of agitating. 7. The treatment step (I) comprises: (I ') adding the coal or other carbonaceous material to the one or more alkaline earth metal chlorides, the one or more alkali metal chlorides or the A wet-milling substep in the presence of a mixture of chlorides; (I ″) agitating the aqueous mixture of substep (I ′) with the nitric acid at an elevated temperature below the oxidation temperature of the coal or other carbonaceous material. The method of claim 6 comprising the substeps of: 8. A process according to any one of claims 5 to 7 wherein step (I) is carried out at about atmospheric pressure and the elevated temperature of step (I) is about 85-130 ° C. . 9. A process according to any one of claims 1 to 4, wherein step (I) is carried out at about atmospheric pressure and the elevated temperature of step (I) is about 85-95 ° C. . 10. A method according to any one of claims 5 to 6 wherein step (III) is carried out at about atmospheric pressure and said elevated temperature of step (III) is about 85-95 ° C. .