JPH0368690A - Manufacture of water-resistant fuel aggregate - Google Patents

Abstract

PURPOSE: To satisfy both mechanical properties and water resistance under economically and ecologically allowable conditions by agglomerating a finely pulverized fuel substance with an org. binder and an oxidizing agent and the obtained agglomerate is subjected to a storing treatment.

CONSTITUTION: An oxidizing agent is mixed with either a finely pulverized fuel substance or an org. binder, with each of these compds. or with a mixture of them, and then the obtd. mixture is agglomerated. The obtd. agglomerate is dried by heating. The fuel substances are, e.g. a fine coal powder or scraps, fine wood powder, fine coal coke powder and fine petroleum coke powder. The organic binder is pref. a starch or a starch deriv. The oxidizing agent is pref. a persulfate, particularly ammonium persulfate. The agglomeration method is pref. granulation, compression, extrusion or molding. A storing condition is pref. in the range of 170 to 300°C. Pref. at least one org. silicon-contg. water repellent is added to the finely pulverized fuel material, the org. binder or their mixture.

COPYRIGHT: (C)1991,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing water-resistant fuel aggregates.The present invention also relates to the composition of the materials used in the method.

The expression "fuel agglomerates" means a physical representation of pulverized fuel material that is easily handled and useful for domestic or industrial applications, including, for example, nodules, briquettes and pellets. I can do it.

BACKGROUND OF THE INVENTION The pulverized fuel materials addressed in the present invention may be carbon-rich materials such as, for example, coal fines or scraps, wood fines, coal coke fines, petroleum coke fines, or mixtures thereof. These materials, especially coal fines and scraps, are produced in large quantities, especially by modern extraction and washing of coal.

More specifically, among the uses that increase the value of these materials, mention may be made of their use in the form of fuel aggregates.

Various methods of aggregating these fines or debris have been proposed, generally using suitable E, i, 1yIl agents or binders to ensure sufficient agglomeration.

Among these remote agents or binders, coal, wood or petroleum tar, lignosulfone salt, clays,
Polysaccharides, and especially starch and starch derivatives, are currently the most used.

Which of these binders is most used? ! Coal tar, however, is currently facing a definite setback in its use due to increasingly stringent environmental protection requirements.

In fact, their use requires that the aggregates thus obtained be subjected to a heat treatment or a fume reduction treatment in order to reduce the concentration of phenolic compounds. By the way, this process causes air pollution that cannot be ignored. Furthermore, if the fume reduction treatment is not complete, the combustion of these aggregates during use can cause the release of fumes that are toxic to humans.

These shortcomings have led to their use being banned in some countries.

These disadvantages due to the use of tar also occur during the use of bitumen as a binder.

To overcome these drawbacks, lignosulfonates,
In particular, methods have been proposed in which ammonium salts are used as binders.

The scientific literature on the use of these products is extensive;
For example, 5UP983.1'r7. ．． 5UP1.01
0.146.5UP1.137,103, EPO097
486 and DE3,277°395 and DDP22
4,331 and USP 4.666.522.

The flocculation method using lignosulfonates is complex;
The work may require considerable skill and skill. especially,
It is necessary to dry the fines to a precise moisture content so as to agglomerate the lignosulfonate-fine powder mixture. Excess or lack of moisture makes this operation impossible.

On the other hand, in the heat treatment which polymerizes the lignosulfonates and thus imparts good water resistance to the aggregates, this results in the release of noxious fumes rich in sulfuric acid, which are a significant source of air pollution.

Methods have been proposed to solve this pollution problem by applying various devices to the associated equipment, in particular by providing soot condensation devices. However, such a device
Even the use of special steel as the material of construction for agglomeration equipment can lead to corrosion problems, which are known to be extremely difficult to control, especially when it is rich in sulfuric acid; It only resulted in replacing the pollution problem. Regardless, whatever solution is attempted, the drawbacks associated with the use of lignosulfonates make it a cumbersome process.

Furthermore, the agglomerates produced and left behind by this method exhibit the disadvantage that during their combustion they generate sulfur-containing residues which are also found in particular in the soot.

Processes have been proposed to replace binders with clays, especially bentonites, which do not exhibit the above-mentioned disadvantages associated with pitch, tar and lignosulfonates (USP 4.02
5,596 and DBI.

671.365), L However, the aggregates obtained by these methods do not exhibit all the required physical properties, in particular their mechanical strength is insufficient and their behavior in water is poor. There is.

Therefore, these methods have not been developed in practice.

For example, USP 3,726,652 and DE 3.22
The use of starch as a binder, used alone or in mixtures with other binders as taught by 7.395 and EP 097486, has also been proposed, which shows a number of advantages.

A comparative study on beretization conducted at Berkeley University in 1982 [Gay V.
Y) OJ: D,W, FOER3TENAU] showed that with respect to asphalt emulsions or bentonite, starch led to better results in:

- mechanical compression resistance; - abrasion resistance, and - Impact resistance.

Furthermore, starch can be used without restriction in industrial plants that were originally designed for the use of tar and bitumen, which are currently the most used binders. Therefore, no additional investment is required to use it,
Furthermore, miscellaneous costs of the plant are reduced.

Finally, no toxic and/or polluting soot is produced by the combustion of starch-bound aggregates; however, this method does not require the use of starch-bound aggregates, which have a very pronounced susceptibility to water, such as that caused by bentonite. This poses a major drawback: it becomes impossible to store them outdoors.

To overcome this drawback, it is possible to combine the starch with tar, asphalt or bitumen, or to insolubilize the starch with resins based on urea-formaldehyde, phenol-formaldehyde, melamine-formaldehyde or getone-formaldehyde, or mixtures thereof. Proposed.

None of these solutions is satisfactory, since all leave open the problem of emitting toxic and polluting soot during the combustion of the I aggregates so obtained.

In order to make these fuel aggregates based on carbohydrates water-resistant, it has also been proposed to mix therein a non-negligible proportion of strong acids, in particular gJ acid, and to treat the aggregates at temperatures between 200 and 540°C. (see IJSPl, 507,673).

This solution is not satisfactory, since the problem of releasing corrosive fumes as well as lignosulfonates during processing remains.1. Furthermore, handling strong acids is always difficult and therefore a restrictive operation.

It has also been proposed to cover the aggregates with water-miscible sheets or films obtained by applying emulsifying wax. Such solutions, although novel, are cumbersome due to the amount of wax used;
Also, if these aggregates are subjected to impact during transport and the protective sheet deteriorates, the waterproof properties thus imparted to the aggregates may be altered.

Finally, a method has been proposed for producing water-resistant fuel aggregates consisting of carbohydrates as binders on the one hand and organosilicon-containing agents as water admixing agents on the other hand distributed within a compositional range (see EP 89400071). .

Although such aggregates have adequate weather resistance, they have the disadvantage of exhibiting a relatively brittle surface condition when they are wet.

Such susceptibility is evidenced by the well-known deterioration of their surfaces during handling, producing negligible amounts of debris.

Therefore, none of the existing methods is able to produce fuel aggregates that simultaneously satisfy mechanical properties and water behavior under economically and ecologically acceptable conditions.

[The problem that the invention aims to solve jJ! ] The present invention therefore provides a fuel, 11!, which overcomes the shortcomings of the prior art and which meets various requirements or practices better than existing ones! The purpose is to provide a collective.

[Means for Solving the Problems] The inventors believe that this purpose is to agglomerate pulverized fuel material using an organic binder and an acidic agent, and then heat and dry the agglomerates thus obtained. He achieved the feat of discovering that things can be achieved by doing things.

That is, the method for producing water-resistant fuel aggregates according to the invention comprises: using a pulverized fuel material, an organic binder and an oxidizing agent, combining the oxidizing agent with either the fuel material or the organic binder, or with each of these compounds; It is characterized in that it is mixed with a mixture thereof, the mixture thus obtained is subjected to an agglomeration treatment, and the aggregate obtained upon completion of the agglomeration treatment is subjected to a heating drying treatment.

According to an advantageous embodiment of the method according to the invention, the organic binder is selected from the group consisting of molasses, cellulose, hemicellulose, flour, proteins, starch, derivatives of these products and mixtures thereof, Derivatives are preferred.

According to another advantageous embodiment of the method according to the invention, the oxidizing agent is of the group consisting of hypochlorites, perborates, persulfates, percarbonates, bromates, peroxides and mixtures thereof. A water-soluble oxidizing agent selected from over 1i! Acid salts are preferred, and ammonium pervA acid is particularly preferred.

It is of interest to combine the action of these oxidizing agents with that of suitably selected metal ions which are recognized to have catalytic properties with respect to the oxidation reaction. can be mentioned.

When the organic binder involved in the process according to the invention is starch or a starch derivative, these terms have the following meanings.

- With respect to Fj flour, native starches of any origin, i.e. natural obtained from, for example, potato, challah mackerel, corn, waxy corn, high amylose Indian corn, wheat and granulated fractions made therefrom, barley and sugar sorghum; With regard to hybrid starches and single starch derivatives, it is advantageous that they are native starches which can be rendered soluble in cold water by physical treatment of physical and/or gelatinization.

In the method according to the invention, the following components are used in the following proportions relative to the weight of the pulverized fuel material:

-0.2 to 25% by weight, preferably 1 to 15% by weight, more preferably 2 to 7% by weight of an organic binder, and -0.01 to 10% by weight, preferably 0.025 to 5% by weight, More preferably 0.05 to 3% by weight of oxidizing agent.

According to an advantageous embodiment of the method according to the invention, the water-soluble oxidizer can be added in powder form to the pulverized fuel material and/or to the organic binder and/or to the mixture of both.

According to another preferred embodiment Ba, the oxidizing agent can be added as an aqueous solution to the fuel material and/or to the mixture of fuel material and organic binder.

According to the method according to the invention, the agglomeration method used is selected from the group consisting of granulation, pressure compaction, extrusion and molding. These techniques are known per se and are described in EPO97
486.

Furthermore, if the method described above is followed, the aggregates obtained at the end of the agglomeration process will generally be about 150-500°C, preferably about 170-500°C. 300℃, more preferably 190~
A heat drying treatment is performed under a temperature condition of 250°C.

According to another advantageous embodiment of the method according to the invention, in order to limit the risk of re-absorption of water by capillary action in the fuel agglomerates obtained according to the method of the invention during exposure to adverse weather conditions. , at least one organosilicon-containing waterproofing agent is added to the pulverized fuel material, organic binder, oxidizing agent, or mixture thereof.

The organosilicon-containing waterproofing agent is preferably a compound whose structural unit is represented by the formula () (in the formula, R and R1, which may be the same or different from each other, are organic groups), and which includes non-reactive silicone oil, silicone Resins, especially hydroxide,
Alkylated, arylated, hydroalkylated and hydroarylated reactive silicone oils;
Preferably, it is selected from the group consisting of mixtures of these products and emulsions that can be prepared from these products.

In addition, the organosilicon-containing waterproofing agent has the general formula (wherein R2 is an alkyl, alknyl or aryl group, X is an alkali or alkaline earth metal, and n is 1 to
10), preferably silicone potassium.

The composition of the substances used in this advantageous embodiment of the process according to the invention constitutes within the scope of the present application a new industrial product of the same title as the fuel aggregate thus obtained.

According to another embodiment of the invention, together with the aggregates, e.g. carbonates, quicklime or slaked lime, dolomites, gaicates, clays, latexes, borax, polyphosphates, phosphates, concentrated milk and/or whey cements, Other components such as polyvinyl alcohol, alcohol and thermosetting resins can be included.

The proportion of these components is 15% by weight based on the weight of the pulverized fuel material.
Preferably, the particle distribution of these components should be close to that of the pulverized fuel material, which may range in weight percent.

EXAMPLES The invention will be understood more fully by means of the following examples of advantageous embodiments.

Example 1 A charcoal waste based nodule/control mixer was introduced with 50 ko of charcoal waste with a tri-like distribution of less than 111 of one component and 3 kQ of natural wheat starch as the other component. After heating this mixture to 50°C,
4.5 liters of water were introduced there. The resulting mixture was heated to 90° C. and mixed for 1/4 hour. The final moisture content, determined by a moisture content known under the name CENCO, was then 8.5%. Add the mixture to Sahat =r Nle7- (5AHUT
The temperature of the mixture was about 70°C during agglomeration, and the adjusted pressure of the press was 16.7 x 105N in linear pressure. /m, the roll speed of the press is 5"p~, and the output of the press is 6"
It was kM.

In this way, a lump charcoal was obtained which, when freshly produced, exhibits sufficient cohesive strength to withstand transportation.

The strength of these nodules, as measured by a counterweight compression needle developed by Sahat Conrair, was:

As manufactured 294.3 N After drying for 24 hours at ambient temperature 686.7 N100
After heating and drying at ℃ for 1 hour, 1765.8 N130
These pellets were heated to dry for 1 hour at 0.degree. C. and then immersed in cold water. It was observed that the nodules disintegrated very rapidly. After a few minutes, the aggregates showed no aggregation.

These results indicate that if only starch-type binders are used, agglomerates of charcoal debris, #, with good mechanical properties but no water resistance can be produced.

Example 2 In a coal waste nodule mixer according to the invention, 50 k (J) of coal waste having properties comparable to those of the waste of Example 1 and 2.5 kg of natural wheat starch were homogeneously mixed.

The resulting mixture was heated to 50° C. with mixing and then 25 g of ammonium persulfate diluted with 2.5 liters of water were added. This mixture was heated to 90'
The mixture was kneaded at C for 174 hours. The final moisture content at that time was 8%.The mixture was then agglomerated by pressure compaction under the same conditions as in Example 2.

In this way, new! ! ! Obtained a small lump of coal waste with sufficient cohesion to be able to be transported when left behind.2
Next, the obtained small lump charcoal was heated and dried at a temperature of 220° C. for 2 hours.

The intensities of these nodules, measured as in Example 1, were:

During manufacturing 20ON220℃
After heating and drying for 2 hours at 1300 N, these pellets were then immersed in cold water. No disintegration was observed even after soaking for several hours.

The mechanical strength of the nodules remained unchanged after residence in water, and no disruption of their surface condition was observed during their handling after immersion.

This example shows that by adding 5% dry weight of natural starch and 0.05% ammonium persulfate to the weight of the fuel layer, an agglomerate which meets the requirements of the technology in terms of mechanical strength and behavior towards water is produced. This shows that it will be possible to obtain

Example 3 - Coal waste pellets according to the invention In the same mixture of coal waste and starch as the mixture of Example 2,
The mixture was treated as in the mixture of Example 2, with the addition of 50 g of sodium perborate under the same conditions as in Example S2. The final moisture content of the mixture was the same as in Example 2.

In this way, a pellet of coal waste was obtained which had sufficient cohesive strength to be transported when newly manufactured.

Next, these small lumps were heat-dried at a temperature of 220° C. for 2 hours.

The intensities of these nodules, measured as in Example 1, were:

During manufacturing 35ON220℃
After heating and drying for 2 hours at 1100 N, these pellets were then immersed in cold water. No disintegration was observed even after soaking for several hours.

The physical strength of the nodules remained the same after incubation and after simple drying. No disruption of their surface conditions was observed.

In this example, by adding 5% natural starch and 0.1% sodium perborate on a dry basis based on the weight of the fuel layer,
It is shown that it becomes possible to obtain aggregates that meet the requirements of the technology both in terms of mechanical strength and behavior towards water.

Example 4 A limestone nodule according to the invention Rhodosil siliconate (RH
ODOR3IL 5ILICONATE) 51 T
Waterproofing agent [0-7-7'-Ran (RHONE-POL)
1100 g of commercially available silicone potassium having a solids content of approximately 49% were added.

The mixture was treated as in the mixture of Example 2.

In this way, limestone nodules were obtained which had sufficient cohesive strength to be transported when freshly manufactured.9 These nodules were then heated and dried at a temperature of 230° C. for 2 hours.

The intensities of these nodules, measured as in Example 1, were:

Manufacturing time 200 N230
After heating and drying for 2 hours at 1400 N, these blobs were then placed in cold water for 15 minutes. was soaked for a while. After this residence, the water uptake of the nodules was only □1.6%.

The mechanical strength of the nodules remained unchanged after residence in water, and no disruption of their surface condition was observed during their handling after immersion.

In this example, the addition of 5% natural starch, 0.05% ammonium persulfate and 0.1% silicone potassium on a dry basis to the weight of the fuel layer improves mechanical strength and water behavior. It is hoped that it will be possible to obtain aggregates that meet the requirements of the technology, and that the uptake of water by these aggregates can be significantly limited in cases where water is undesirable.

Claims (1)

[Claims] 1. Using a pulverized fuel material, an organic binder and an oxidizing agent, the oxidizing agent being mixed with either the fuel material or the organic binder, or each of these compounds, or a mixture thereof; A method for producing a water-resistant fuel aggregate, which comprises aggregating the mixture thus obtained, and heating and drying the aggregate obtained upon completion of the agglomeration process. 2. The method of claim 1, wherein the organic binder is selected from the group consisting of molasses, cellulose, hemicellulose, flour, protein, starch, derivatives of these products and mixtures thereof, preferably starch or starch derivatives. . 3. The oxidizing agent is hypochlorite, perborate, persulfate,
3. A water-soluble oxidizing agent selected from the group consisting of percarbonates, bromates, peroxides and mixtures thereof, preferably a persulfate, especially ammonium persulfate. the method of. 4. The method according to any one of claims 1 to 3, wherein the agglomeration method used is selected from the group consisting of granulation, pressure compaction, extrusion and molding. 5. The temperature conditions associated with the heat drying treatment are generally about 1
The method according to any one of claims 1 to 4, wherein the temperature is 50 to 500C, preferably 170 to 300C, more preferably 190 to 250C. 6. The organic binder is obtained from natural starch of any origin, such as potato, cassava, corn, waxy corn, high amylose-containing corn, wheat or granulated fractions made therefrom, barley or sugar corn. 3. A method according to claim 2, wherein the starch is either a natural or hybrid starch or a starch derivative consisting of physically and/or chemically modified starch. 7. A method according to claim 6, wherein the organic binder is a natural starch which can be made cold water soluble by physical treatment of boiling extraction in a drum and/or gelatinization. 8. Organic binder in a proportion of 0.2 to 25% by weight, preferably 1 to 15% by weight, more preferably 2 to 7% by weight, and 0.01 to 10% by weight, based on the weight of the pulverized fuel material. 8. The process according to claim 1, wherein the oxidizing agent is used in a proportion of preferably 0.025 to 5% by weight, more preferably 0.05 to 3% by weight. 9. A method according to any of claims 1 to 8, wherein at least one organosilicon-containing waterproofing agent is added to the pulverized fuel material, organic binder, oxidizer or mixture thereof. 10. The structural unit of the organosilicon-containing waterproofing agent is the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) (In the formula, R and R_1, which may be the same or different from each other)
is an organic group), preferably non-reactive silicone oils, silicone resins, especially hydroxylated, alkylated, arylated, hydroalkylated and hydroarylated reactive silicone oils and products thereof. or has the general formula ▲ mathematical formula, chemical formula, table, etc. ▼ (II) (wherein R_2 is alkyl, alkenyl or 10. A process according to claim 9, wherein the compound is selected from the group of silicone salts, preferably silicone potassium, wherein X is an alkali or alkaline earth metal and n is from 1 to 10.