DD294968A5 - METHOD FOR PRODUCING A WATER-CONSISTENT, BURNING AGGLOMERATE - Google Patents

Abstract

The invention relates to a process for the preparation of a water-resistant combustible agglomerate. For this purpose, a finely divided, combustible material, an organic binder and an oxidizing agent are used. The oxidizing agent is mixed with either the combustible material or the organic binder or with one or other of these products or their mixture. The mixture thus obtained is subjected to agglomeration treatment, and the agglomerate obtained at the end of the agglomeration treatment is subjected to drying by heating or oven drying, respectively. manufacture; combustible agglomerate; organic binder; Oxidant; drying; Baking}

Description

in particular, its mechanical resistance is insufficient and its resistance to water is mediocre.

This is due to the fact that these methods have not developed in practice. It was also recommended to use starch as a binder, when used alone or in mixture with others Binders is used, as taught, for example, the patents US 3726652 and DE 3227395 or EP 0097486,

has many disadvantages.

A comparative study of a 1982 carried out at the University of Berkeley pelletization (thesis

by K.S.Sastry and D.W. Fuerstenau) showed that, based on an emulsion of asphalt or on bentonite, starch felt better results in the following areas:

the mechanical compression resistance, the abrasion resistance,

the impact resistance.

In addition, the strength can be used without restriction in industrial devices originally intended for the Use of pitch or bitumen, which are currently the most widely used binders, were

their use thus requires no additional investment. Moreover, the maintenance of the devices is reduced.

Finally, the combustion of the agglomerates bound by starch does not produce any toxic and / or polluting

Smoke.

However, and this is a considerable disadvantage, the starch-based agglomerates as well as those possess Based on bentonite a very pronounced Wasserempfindlichkoit, which makes their storage in the open air impossible. It was recommended to remedy this disadvantage, the Sta, Ke with pitch, asphalt or bitumen to associate or the Starch with resins of urea-formaldehyde, phenol-formaldehyde, melamine-formaldohyde, ceton-formaldehyde type or

to make their mixtures insoluble.

None of these solutions is satisfactory, as all contribute to the problem of releasing toxic and polluting gases

the combustion of the agglomerates thus obtained to rest.

It has also been recommended to render these combustible carbohydrate-based agglomerates water resistant (cf. US 1507673) to incorporate a strong acid in not negligible proportion, in particular phosphoric acid, and

to treat these agglomerates at a temperature between 200 and 54O ⁰ C.

This solution is unsatisfactory in that, as in the case of lignosulfonates, the problem of release during treatment

poses corrosive gases. Moreover, the handling of a strong acid is always a delicate measure and thus a hindrance.

It was also recommended to coat the agglomerates with a water-repellent layer or skin that penetrates through Applying an emulsified wax is obtained. Although such a solution is original, it is costly due to

the amount of wax used, and the protection against moisture imparted to the agglomerates in this way can change if these agglomerates experience a shock in the course of their transport, which leads to destruction of the

Protective layer leads. Finally, it was recommended (see EP 89400071) to produce water-resistant, combustible agglomerates which are within

Their composition is partly based on a carbohydrate as a binder and partly on an organosilicon-based agent as a water-repellent agent.

Such agglomerates, while having useful resistance to weathering, have the disadvantage of

to have a relatively brittle surface when wet. Such sensitivity manifests itself in an obvious destruction of their skin during their handling, whereby dusts in not negligible

Amount to be formed. As a result, there is no process that makes it possible, under economic and environmentally acceptable conditions

To obtain flammable agglomerates, which also have satisfactory mechanical properties and water resistance.

Object of the invention

The aim of the invention is therefore to overcome the disadvantages of the prior art and to provide a combustible agglomerate which better meets the various requirements of the practice than the existing ones.

Explanation of the essence of the invention The Applicant has now found that this goal can be achieved by a fine-to-flammable material with

an organic binder and an oxidizing agent agglomerated and the resulting agglomerate a

Subjecting drying treatment by heat or oven drying. Accordingly, the process for producing combustible, water-resistant agglomerates according to the invention is thereby

characterized in that one uses a one-part, combustible material, an organic binder and an oxidizing agent, the oxidizing agent mixes either with the combustible material or the organic binder or with one or other of these products or their mixture, subjecting the resulting mixture to an agglomeration treatment and subjecting the resulting agglomerate to a drying treatment by heating or oven drying at the end of the agglomeration treatment.

According to an advantageous embodiment of the method according to the invention, the organic binder is among the Molasses, celluloses, hemicelluloses, flours, proteins, starches, derivatives of these products and

their mixtures are selected, with the starches and the starch derivatives being preferred.

According to a further advantageous embodiment of the method according to the invention, the oxidizing agent is a

water-soluble oxidizing agent selected from hypochlorites, perborates, persulfates, percarbonates,

the bromates, the peroxides and mixtures thereof, wherein the persulfates are preferred and the ammonium persulfate is particularly preferred.

It may be of interest, with the action of these oxidants, that of correspondingly selected metal ions which

because of their catalytic! Effect with respect to Oxidationsreaktjonen are recognized to associate. As an example, mention may be made of copper, zinc, iron and other divalent metal ions.

When the organic binder used in the method according to the invention is a starch or a starch derivative,

These terms are used to describe the strength, the native strengths of any origin, the natural ones

Starches or starch hybrids, for example, the potato, the manioc, the maize, the waxy corn, the high-corn Amylosegehalt, the grain or wheat and the granulometric fractions that may be produced therefrom Originated from barley or sorghum, and as regards the starch derivative, based on physical and / or chemical Way modified starches. Advantageously, the organic binder is a native starch which may optionally be replaced by a physical cooking Extrusion treatment and / or gelatinization treatment on the drum made soluble in cold water

has been.

Based on the weight of the fine-toluene, combustible materials, are used in the inventive method:

a content of 0.2 to 25% by weight, preferably 1 to 15% by weight, and more preferably 2 to 7% by weight, of organic binder

Proportion of 0.01 to 10% by weight, preferably 0.025 to 5% by weight and in particular 0.05 to 3% by weight of oxidizing agent. According to an advantageous embodiment of the method according to the invention, the water-soluble oxidizing agent in

powdered form are added to the finely divided, combustible material and / or the organic binder and / or the mixture of the two.

According to a further preferred embodiment, the oxidizing agent in aqueous solution to the combustible material

and / or the mixture of this material and the organic binder.

According to the process of the invention, the agglomeration technique under the politicization, the Pressure compression, extrusion and molding. These techniques are themselves known and will be

for example described in EP 0097486.

Incidentally, it is always subjected to the above method at the end of the agglomeration treatment

obtained agglomerate a heat treatment by heat under temperature conditions, which are generally between about 150 and 500 ° C, preferably between 170 and 300 ⁰ C and in particular between 190 and 250 ° C.

According to a further advantageous embodiment of the method according to the invention, at least one

Organosiloxane-based or organo-silicic acid-based water-repellent agent added to the finely divided, combustible material, the organic binder, the oxidizing agent or mixtures thereof to limit any risk of water uptake by capillarity of the agglomerates obtained by the process according to the invention, when these Wetterunbilden are exposed ,

Preferably, the organosilicon-based water repellent is a compound whose structural unit is replaced by the

formula

} (D

wherein R and Ri, which may be identical or different, are organic radicals, said compound preferably being selected from non-reactive silicone oils, silicone resins, especially hydroxylated, alkylated, arylated, hydroalkylated, hydroarylated, reactive silicone oils, and the like Mixtures of these products and the emulsions which can be prepared from these products, or also a compound selected from among the siliconates of the general formula

Si

OX

⁰ - (ID

R _{2 is} an alkyl, alkenyl or aryl group, X is an alkali or alkaline earth metal atom and 1 s η s 10, wherein the Potassium siliconate is preferred. The composition used in an advantageous embodiment of the method according to the invention is in For this particular application, it represents a new industrial product, as well as the flammable ones thus obtained Agglomerates. According to a further embodiment of the invention can be added to the agglomerates other ingredients, such as. B. Carbonates, quicklime or extinguished lime, dolomite, alkali silicates, clays, latex, borax, polyphosphates, phosphates, milk

and / or lactoserum in concentrated form, cement, polyvinyl alcohols and thermosetting resins. The proportion of this

Ingredients can reach 15% by weight, based on the weight of the finely divided material. The granulometric distribution

these components must preferably be similar to that of the finely divided material.

Embodiments of the invention will be explained in more detail with reference to the following examples, which extend to advantageous embodiments.

example 1 Spheres or pellets on fine coal base / comparison In a mixer one brings partly 50 kg fine coal with a granulometry below 1 mm and partly 3kg native Cereal starch. This mixture is heated to 5O ⁰ C and then enters 4.51 of water. Mix the mixture thus obtained

for a quarter of an hour with heating, the temperature rises to 9O ⁰ C. The final moisture measured using a moisture balance known as CENCO is then 8.5%. The mixture is passed through

Pressure compression on a press of the type Sahut Conreur agglomerated. Under the treatment parameters one makes provision for the temperature of the mixture, which at the time of the Agglomeration is about 70 ⁰ C, the pressure for the regulation of the press, which is 16.7 χ 10 ⁵ N / m linear, the Speed of the cylinders of the press, which is 5rpm, and the capacity of the press, which is 6kW. This gives carbon spheres with sufficient cohesion in the green state to survive transport. The durability of these balls, determined with the help of a counterweight compensometer developed by Sahut Conreur, has the following values:

in green condition 294.3 N

After drying for 24 hours at room temperature 686.7 N

after one hour of heat-drying at 100 ⁰ C,

followed by one hour of heat drying

at 13O ⁰ C 1765.8 N.

These balls are then immersed in cold water. One finds that they fall apart very quickly. After a few minutes, the agglomerate no longer has any cohesion at all.

These results show that it is possible to form fine coal · agglomerates using only a starch type binder, which have good mechanical properties but are not resistant to water.

Example 2 Fine coal balls according to the invention In a mixer, intimately mixed 50 kg of fine coal with the properties identical to those of the fine coal of Example 1

and 2.5 kg of native corn starch. The resulting mixture is heated while working to a temperature of 50 ° C. It is then mixed with 25 g of ammonium persulfate, diluted in 2.51 of water. The mixture is then worked on for a quarter of an hour by bringing the temperature of the mixture to 9O ⁰ C. The final moisture is then 8%. The mixture is then subjected to agglomeration treatment by pressure compression under the same conditions as in Example 1. This gives fine coal pellets with a sufficient Kohä'iion green state to survive a transport. These are then subjected to heat drying for 2 hours at a temperature of 220 ° C.

The durability of these spheres, measured as in Example 1, has the following values:

in green condition 200N

after a heat drying of 2 hours at 22O ⁰ C 1300N.

These balls are then dipped in cold water. It will not work even after immersing for several months Disaggregation detected. The mechanical resistance of the balls remains unchanged after their residence in water, and it is none Surface deterioration observed during handling after immersion. This example shows that the addition of 5% native starch and 0.05% ammonium persulfate to dry weight, based on

the weight of the combustible fine coal, it makes it possible to achieve agglomerates that meet the requirements of the technology in terms of mechanical resistance and water resistant.

Example 3 Fine coal balls according to the invention A mixture of fine coal and starch identical to that of Example 2 is added to the same Conditions 50g of sodium perborate, after which the mixture is allowed to undergo the same treatments as the mixture of Example 2. The final moisture of the mixture is identical to that of Example 2. Thus, fine coal balls having sufficient green state cohesion are obtained to survive transportation. These Balls are then subjected to heat drying for 2 hours at a temperature of 220 ° C. The durability of these spheres, measured as in Example 1, has the following values: In green condition 350N

after a 2stündigenWärmetrockni! ng at 220 ⁰ C. 1100N.

These balls are then dipped in cold water. It does not decay even after several months of immersion

observed.

Their mechanical resistance remains unchanged after their stay in water and after a simple drainage. It

no degradation of its surface quality is observed.

This example shows that the addition of 5% native starch and 0.1% sodium perborate as dry weight, based on the Weight of the fine coal of the combustible material, it allows to achieve agglomerates that meet the requirements of technology

in terms of mechanical resistance and water resistance are sufficient.

Example 4 Fine coal balls according to the invention It is added to a mixture of fine coal, starch and ammonium persulfate, identical to that of Example 2,100g

Rhodorsil Siliconate 51T water repellent (potassium siliconate, available from RHONE-POULENC with a

Dry content of about 49% is marketed). This mixture is subjected to the same treatments as the mixture of Example 2. This gives fine coal balls,

which have sufficient green state cohesion to withstand transport. These balls are then subjected to a heat drying of 2 hours at a temperature of 230 ° C.

The durability of these spheres, measured as in Example 1, has the following values:

in green condition 200N

after 2 hours of heat drying at 230 ° C 1400 N.

These balls are then immersed in cold water for 1 hour. After this stay is their Weight of water only 1.6%. The mechanical resistance of the balls remains unchanged after your stay in water, and there will be no degradation of their Surface texture observed during handling after immersion. This example shows that the addition of 5% native starch and 0.05% ammonium persulfate and 0.1% potassium hydroxideate Dry weight, based on the weight of the fine coal of the fuel, it allows to obtain agglomerates containing the Technological requirements in terms of mechanical resistance and water resistance are sufficient, and so are

allows to greatly limit the water absorption of these agglomerates, if this is undesirable.

Claims (10)

A process for producing a water-resistant, combustible agglomerate, characterized in that one uses a finely divided, combustible material, an organic binder and an oxidizing agent, the oxidizing agent either with the combustible material or the organic binder or with one or the other of these Mixing products or their mixture, subjecting the mixture thus obtained to agglomeration treatment and subjecting the agglomerate obtained at the end of the agglomeration treatment to drying by heating or oven drying, respectively. 2. The method according to claim 1, characterized in that the organic binder is selected from molasses, celluloses, hemicellulose, flours, proteins, starches, the derivatives of these products and mixtures thereof, wherein the starches and starch derivatives are preferred. 3. The method according to claim 1 and 2, characterized in that the oxidizing agent is a water-soluble oxidizing agent selected from hypochlorites, perborates, persulfates, percarbonates, bromates, peroxides and mixtures thereof, wherein the persulfates are preferred and the Ammonium persulfate is particularly preferred. 4. The method according to claim 1 to 3, characterized in that the agglomeration technique used is selected from the pelleting, the pressure compaction, the extrusion and the molding. 5. The method according to claim 1 to 4, characterized in that the temperature conditions resulting from the drying by heating, generally between about 150 and about 500 ⁰ C, preferably between 170 and 300 ⁰ C and in particular between 190 and 250 ^0th C, lie. 6. The method according to claim 2, characterized in that the organic binder is either a native starch of any origin, a natural starch or a starch derivative or hybrid, for example, from the potato, the cassava, the maize, the waxy maize, the high corn Amylose content, the grain or wheat and the granulometric fractions which can be produced therefrom, barley and sorghum, or a starch derivative consisting of a physically and / or chemically modified starch. A process according to claim 6, characterized in that the organic binder is a native starch which has optionally been solubilized in cold water by a physical boiling extrusion treatment and / or gelatinizing treatment on the drum. 8. The method according to claim 1 to 7, characterized in that, expressed as the weight ratio of the finely divided, combustible material, are used: a proportion of 0.2 to 25Gew .-%, preferably 1 to 15Gew .-% and in particular 2 to 7Gew %, organic binder, a proportion of 0.01 to 10% by weight, preferably 0.025 to 5% by weight and in particular 0.05 to 3% by weight of oxidizing agent. 9. The method according to claim 1 to 8, characterized in that at least one organosilicon-based or organo-silicic acid-based water-repellent agent is added to the finely divided, combustible material, the organic binder, the oxidizing agent or their mixture. 10. The method according to claim 9, characterized in that the organosilicon-based water-repellent agent is a compound whose structural unit is represented by the formula (I) wherein R and Ri, which may be identical or different, are organic radicals, the compound being preferably selected from non-reactive silicone oils, silicone resins, reactive, in particular hydroxylated, alkylated, arylated, hydroalkylated, hydroarylated, silicone oils and the mixtures of these products and the emulsions which can be prepared from these products, or a compound selected from among the siliconates of the general formula Si OX worm. R _{2 is} an alkyl, alkenyl or aryl group, X for an alkali or alkaline earth metal atom is 1 <η <10, wherein the potassium siliconate is preferred. Field of application of the invention The invention relates to a method for producing a water-resistant, combustible agglomerates. It concerns also the composition used in this process. By the term "flammable agglomerates" is any manifestation (one-piece, flammable materials that light can be transported and used for domestic and industrial purposes designated. You can as an example Lead balls, briquettes and pellets. Thieves! Of the present invention, finely divided, combustible materials can all carbon-rich Be substances such. As fine coal or coal dust, fine coal of charcoal, fine coal of Kühlenkoks, fine coal of Petroleum coke or a mixture of these products. These materials and in particular the fine coal and the coal dust become formed by the modern extraction and washing processes, in particular of coal, in large quantities. Among the value-enhancing applications of these materials one can especially their use in the form of flammable Call agglomerates. Characteristic of the known state of the art Various Agglomeration techniques for this Finkink and coal dust, in which generally additives or Binders which are suitable for ensuring sufficient cohesion have already been recommended. Among these additives or binders are the most commonly used pitches of hard coal, charcoal or Petrol pitch, bitumen, the lignosulfonates, the tonics, the polysaccharides and among these in particular the starches and the Starch derivatives. The most common of these binders is undoubtedly bituminous coal pitch, however, since the requirements regarding the As environmental protection becomes more and more stringent, its use today is subject to some restriction. In fact, its use requires that the agglomerates thus obtained undergo a thermal or smoke removal treatment to reduce the concentration of phenolic compounds. However, this treatment does not lead to one negligible atmospheric pollution. Moreover, if the smoke extraction is not complete, the Combustion of these agglomerates at the time of their use to release harmful to humans Smoke. These disadvantages have led to certain countries prohibiting their use. The disadvantages associated with the use of pitch are also found in the use of bitumen as a binder. To remedy these disadvantages, it has been recommended to use as a binder on lignosulfonates, in particular Ammonium lignosulfonates, to access. The scientific literature concerning the use of these products is extremely extensive, and one can For example, the patents SU 983147, SU 1010146 and SU 1137103, EP 0097486 and DE 3227 395 or DD 224331 and US 4666522 call. It turns out that the agglomeration technique with lignosulphonates is complex and their implementation a large Mastery required. In particular, it is necessary to dry the fine coal to a precise moisture content, that the mixture Lignosulfonate fine coal can be agglomerated, with an excess or a lack of water this Procedure makes impossible. On the other hand, the thormic treatment to polymerize the lignosulfonates and thus the agglomerates a good Resistance to water, a release of harmful, sulfuric acid rich vapors or Gases - a non-negligible cause of atmospheric pollution. It was recommended to solve this problem of contamination by using different devices Equipment and in particular by providing facilities for the condensation of vapors or flue gases. However, such devices could only result in the problem of contamination on a corrosion problem which is known to be, especially when dealing with the treatment of sulfuric acid Condensates, is extremely difficult to control, even if one as a material component of Agglomeration devices used special steels. In any case, regardless of the solutions considered, with the use of the lignosulfonates associated disadvantages a costly or difficult technology. Moreover, the agglomerates produced by this technique have the disadvantage of sulfur-containing combustion Residues form? .U, which are found in particular in the flue gases. Methods which do not have the disadvantages inherent in pitch, dom tar and lignosulphonates have been recommended have, in which these binders are replaced by clays and especially the bentonite (US 4025596 and DE 1671365). However, the agglomerates obtained by these techniques do not have the required physical properties,