JPS6025076B2 - Method for producing deashed coal/petroleum mixed fuel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a deashing process in which coal particles in a coal/water slurry are granulated into pellets, ash is separated and removed, and then the pellets and heavy oil are heated and mixed to dehydrate them. This invention relates to a method for producing a coal/oil mixed fuel.

In recent years, due to the instability of oil supplies, technological development for effectively utilizing coal has been progressing.

As one of these, research is being put into practical use using a coal/oil mixed fuel made by mixing coal and oil into a slurry. However, conventional coal/oil mixed fuel is usually produced by pulverizing coal into fine particles and mixing it with heavy oil, so the ash contained in the coal is also included in the coal/oil mixed fuel, resulting in a calorific value. This also causes problems with ash disposal. The present invention has been made in view of the above points,
Once the coal is wet-pulverized, a coal/water slurry is prepared, and then this coal/water slurry is sent to an underwater granulation/deashing machine, where a rotating body is rotated at high speed in the slurry to perform underwater granulation, and at the same time remove the ash content. The object of the present invention is to provide a method for producing a deashed coal/petroleum mixed fuel, which is obtained by crushing the pellets and dehydrating them, by separating the pellets, which do not contain ash, and heating and mixing the pellets with heavy oil.

Hereinafter, the configuration of the present invention will be explained based on the drawings.

FIG. 1 is a schematic explanatory diagram showing an example of an apparatus for carrying out the method of the present invention. Coal is supplied to the green mill 1 through a coal input pipe 2, water is supplied through a water supply pipe 3, and an alkali agent is supplied as necessary through an alkali agent supply pipe 4, and the coal is pulverized to prepare a coal/water slurry. Then, this coal/water slurry is sent to a mixing tank 5 together with heavy oil and a granulating agent for mixing. Next, this mixed slurry is sent to an underwater granulation/deashing machine 6, and a rotating body equipped with rotating blades is rotated at high speed in the mixed slurry to granulate coal particles into pellets and separate the ash content. Next, the pellets are separated into waste water containing ash by a first solid-liquid separator 7 comprising a vibrating screen, a bucket conveyor-like discharger, etc., and then the pellets are sent to a deashing coal/petroleum fuel tank 8 together with heavy oil. The water in the pellets is evaporated by heating and mixing, and the pellets are crushed to prepare a dehydrated coal/petroleum mixed fuel. on the other hand,
The wastewater containing ash is sent to a second solid-liquid separator consisting of a thickener and a filter, where it is separated into ash and wastewater, and this wastewater is circulated to a wet mill and reused as water for slurry preparation. Ru. 11 is a dehydrated cake (ash content) extraction pipe, 12 is a waste water extraction pipe, and 13 is a deashed coal/petroleum mixed fuel extraction pipe.

FIG. 2 shows a specific example of an apparatus for carrying out the method of the invention.

Reference numeral 1 denotes a wet mill such as a ball mill, and the wet mill 1 is connected to a coal input pipe 2, a water supply pipe 3, and an alkali supply pipe 4, as in the case of FIG.

The wet mill 1 is connected via a coal/water slurry extraction pipe 14 to a mixing tank 5 equipped with an oak mill 15, and a heavy oil supply joint pipe 16 and a granulating agent supply pipe 17 are connected to this mixing tank 5. has been done. The heavy oil supply joint pipe 16 and the granulating agent supply V supply pipe 17 may be provided simply as shown in the drawings, or may be provided in a group. Furthermore, instead of connecting to the mixing tank 5, the wet mill 1
Alternatively, it may be connected to the coal/water slurry extraction pipe 14.
Underwater granulation/
It is connected to the deashing machine 6. This underwater granulation/deashing machine 6 has a granulation section 21 which has a rotating body 20 that rotates at high speed inside.
and a separation section 22 which is provided adjacent to this granulation section 21 and separates the granulated pellets. As this separating section 22, for example, a discharger such as a conveyor having a fine-mesh silk bucket 23, or a separator such as a vibrating screen is used. In this case, the separation section 22 corresponds to the first solid-liquid separation device 7 shown in FIG. Separation part 2
The second pellet outlet is connected via a pellet conveying line 24 to a deashing coal/petroleum fuel tank 8 which is equipped with a rope sander 25 and a heater 26 and has a dewatering function. A heavy oil supply pipe 27 and a stabilizer supply pipe 28 are connected to the deashed coal/petroleum fuel pipe 8 either singly or collectively. 30
is an ash/wastewater extraction pipe connected to the separation section 22.

In the apparatus configured as described above, coal, water, and an alkaline agent for pH adjustment as necessary are supplied to the wet mill 1, the coal is finely pulverized to prepare a coal/water slurry, and then the coal/water slurry is prepared. After the slurry is sent to a mixing tank 5 together with heavy oil and a granulating agent and mixed (premixing), this mixed slurry is sent to an underwater granulation/deashing machine 6.

In this underwater granulation/deashing machine 6, a rotating body 20 is rotated at high speed in the mixed slurry to granulate coal particles into pellets and separate the ash content. i.e. coal/water slurry;
When granulation occurs by mixing heavy oil and a granulating agent, the coal content in the coal is separated to the pellet side, and the ash content in the coal is separated to the waste water side. This phenomenon is understood to be due to the fact that oil easily adheres to coal and is difficult to adhere to ash. Then, the separation section 22
The pellets are separated into granulated pellets and wastewater containing ash, and the pellets are sent to a deashing coal/oil fuel sinter 8 together with heavy oil and stabilizers, and heated by a heater 26 using water vapor as a heat source. At the same time, the pellets are mixed with heavy oil and a stabilizer by the crusher 25 to evaporate the moisture in the pellets, and the pellets are crushed to produce a deashed coal/petroleum mixed fuel with a low moisture content. Second as above
6 in the device shown in the figure functions as an underwater granulation, deashing, and separator. When supplying the coal/water slurry, heavy oil, and granulating agent to the mixing tank 5, instead of combining them separately as shown in Fig. 2, the granulating agent may be added to the coal/water slurry in advance. Alternatively, the heavy oil and granulating agent may be supplied to the wet mill 1. Alternatively, the heavy oil and granulating agent may be supplied to the wet mill 1. The heavy oil for granulation used in the present invention must have a viscosity necessary as a binder during granulation and be relatively inexpensive.

In this sense, C heavy oil, B heavy oil, atmospheric distillation column bottom oil, etc. are suitable. The amount added for granulation is 6 to 5% by weight, preferably 10 to 4% by weight of the coal on a dry basis. The granulating agent used in the present invention may be anionic, nonionic, cationic surfactants, etc., used alone or in combination, and is appropriately selected depending on the type of coal.

Specifically, the anionic surfactants include alkylbenzene sulfonates, alkyl sulfate ester salts, polyoxyethylene alkyl (alkylphenol) sulfate ester salts, alkyl phosphate ester salts, dialkyl sulfosuccinate ester salts, acrylic acid or/and and maleic anhydride copolymers, polycyclic aromatic sulfonated compounds, or formalin compounds, etc. are used, and as cationic surfactants, alkyl amine salts, quaternary amine salts, etc. are used, and nonionic surfactants are used. Examples include polyoxyalkyl ether, polyoxyethylene alkyl phenol ether, oxyethylene/oxypropylene flock polymer, polyoxyethylene alkyl amine,
Sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, etc. are used, and amphoteric surfactants such as alkyl betaines are used, and 1.
Amine compounds such as 2...3 monoamines and diamines are used. The amount of granulating agent added is 0.01 to 5.0% of coal on a dry basis. % by weight, preferably from 0.05 to 2.
% by weight. Some types of coal, such as Blairsall coal from Australia, are acidic, and in such cases, the alkali agent supply pipe 4 is used to add Ca(OH)2 to the coal/water sludge IJ. Add a neutralizing agent such as pH 6.5 to 11, preferably 7 to 10.
After adjusting the amount, heavy oil and granulating agent are added. In addition, while adding heavy oil and a granulating agent to the coal/water slurry, a neutralizing agent such as Ca(OH)2 was further added to bring the pH to 6.5.
It may be adjusted to 11 to 11, preferably 7 to 10. It is thought that granulation in the present invention is carried out by the following process.

First, the heavy oil and granulating agent added to the coal/water slurry are dispersed, and the granulating agent adsorbs onto the surface of the coal particles to modify the surface of the coal particles.Then, the heavy oil adheres to the surface of the coal particles. An oil film is formed, and then the coal particles adsorbed with heavy oil and granulating agent collide and come into contact with each other, coagulate and combine with oil as a binder, form and grow flocs, and are further consolidated to form pellets. Next, another specific example of the present invention will be explained based on FIG.

The apparatus shown in FIG. 3 includes an underwater granulation/deashing machine 6 equipped with a multi-shaft rotating body 31, a scraper 32, and a discharge machine 33 such as a bucket conveyor in a rice cake, and a waste water containing pellets and ash. It has a first solid-liquid separator 7 that separates ash and a second liquid separator 10 that separates ash and wastewater, and the wastewater separated by the second solid-liquid separator 10 is circulated to the wet mill. It is designed so that it can be reused as water for slurry preparation. The underwater granulation/deashing machine 6 is equipped with a plurality of rotating bodies 31 for granulating coal particles into pellets inside, and pellets that have settled in the internal tank area below these rotating bodies 31 are collected. A discharging machine 3 is provided adjacent to the scraping machine 32 at the other end of the rice cake and discharging the pellets conveyed by the scraping machine 32.
It has 3. In this underwater granulation/deashing machine 6, a plurality of rotating bodies 31 are rotated at high speed in a mixed slurry to granulate coal particles into pellets and separate ash.

Next, pellets and wastewater containing ash are extracted from the underwater granulation/deashing machine 6 and sent to a first solid-liquid separator 7 such as a vibrating screen, where they are separated into pellets and wastewater containing ash.
By this operation, a deashing rate of 40 to 60% can be obtained. Furthermore, wastewater containing ash is removed from the ash/wastewater extraction pipe 34.
The wastewater is sent to the second solid-liquid separator 10 and separated into ash and wastewater, and this wastewater is circulated to the wet mill 1 by connecting the wastewater extraction pipe 12 to the wet mill 1 and reused as water for slurry preparation. do. On the other hand, the separated pellets are sent to the deashed coal/petroleum fuel pipe 8 via a pellet conveying line 35. Other configurations and operations are similar to those in FIG. 2. The invention shown in FIG. 3 uses an underwater granulation/deashing machine having a plurality of rotating bodies, a scraper, and a discharger, so the processing capacity can be easily increased and continuous operation is easy. Moreover, compared to installing multiple underwater granulation/deashing machines with a single rotating body, the cost required for pumps, piping, etc. can be significantly reduced, and wastewater is recycled, making it extremely economical. It has the advantage of being superior. Examples of the present invention will be described below.

Example This example was carried out according to the flow shown in FIGS. 1 and 3.

However, a multi-axis granulation tank equipped with a discharger was used as an underwater granulation/deashing machine during flow, a vibrating screen was used as the first Oka liquid separation device, and a thickener and filtration were used as the second Oka liquid separation device. First, in wet ball mill 1, 52.2k9'h of Blairsall coal with a grain size of less than 3 grains was added on a dry basis (pure coal 47.8k9/h, ash content 4.4k9/h), and water was added to a total of 63.6k9'h. Ca(OH)2 is supplied at 0.2 kg/h and wet-pulverized, and the particle size is 74 or less than 75 from the mill outlet.
%, and a slurry with a concentration of 45% was taken out. Next, in the mixing tank 5, the above slurry is mixed with 31.3 k9/h of water, 0.39 k9/h of anionic granulating agent, and Middle Eastern heavy oil C (500 k9/h).
Viscosity at 0:137.3 centistokes, specific gravity (15
/4°C) 0.95115) 18.3 kg/h and mixed to make a prepared slurry with a total weight of 166.0 k9'h, and this prepared slurry was supplied to the underwater granulation/deashing machine 6. At this time, heavy oil/coal (dry base) = 0.3
5 coal (dry base)/water = 0.55. In the underwater granulation/deashing machine 6, the prepared slurry is granulated underwater by rotating a multi-axis rotating body at 30 pm in the prepared slurry, and then sent to the first solid-liquid separator 7 to form dehydrated granulated charcoal. (Berrett) 85.9k9/h and wastewater containing ash 80.1
k9/h (ash content 2.2k9/h).

The dewatered pellets were sent to a deashed coal/petroleum fuel tank 8, where they were mixed with 29.0k9/h of heavy oil and heated to 90oo with steam. The moisture in the pellets evaporates through steam heating, resulting in a product coal with a total moisture content of 2% and an ash content of 2.2%.
Oil mixed fuel 100k9'h was obtained. The wastewater 80.1k9'h separated in the first solid-liquid separator 7 is further passed through the second solid-liquid separator 7 to circulate water 72.1k9/h and dehydrated cake (ash content) 8.0k9/h (moisture 5.1k9/h). 6k9/h (moisture 5.
6k9'h, ash 2.2k9/h, Ca(OH) 20.
The circulating water was reused as water for slurry preparation, and the dehydrated cake (ash) was taken out of the system. Next, experimental examples conducted by the present inventors will be described.

When coal/water slurry and heavy oil are mixed and sent to an underwater granulation/deashing machine to granulate coal particles into pellets and deash, a granulating agent (anionic surfactant) is used along with the heavy oil. 0.05wt%, 0.1wt%, 0.15wt per coal
%, 0. The completion time of granulation when t% of shoes was added was measured. The results were as shown in FIG. From FIG. 4, it can be seen that in the method of the present invention, by adding a granulating agent to increase the granulation rate, it is possible to significantly reduce the power required for granulation. After the deashing treatment, the pellets are sent to the deashing coal/petroleum fuel tank along with heavy oil, heated and mixed to further evaporate the moisture in the pellets (approximately 15 to 2 skin t%), resulting in water separation of 3wt%. % and 5 wt%, and the stability period of the coal/oil mixed fuel at this time was measured.

The results were as shown in FIG. From Figure 5, by heating and mixing pellets (moisture approximately 15 to 2 vt%) with heavy oil and evaporating, the moisture in the coal/oil mixed fuel can be reduced to about 3 to 2 vt% (when not evaporated, coal It can be seen that if the moisture content in the petroleum mixed fuel is controlled to 7.5 to 1 t%), the stability of the coal/petroleum mixed fuel can be greatly improved. Since the present invention is configured as described above, it is possible to perform deashing at the same time as underwater granulation of coal particles, and it is possible to deash coal particles without providing a separate dryer for drying pellets.・The moisture in the pellets can be removed by heating and mixing it with heavy oil in a petroleum fuel conversion tank, making it possible to efficiently and economically produce dehydrated deashed coal/petroleum mixed fuel. have.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing an example of an apparatus for implementing the method of the present invention, FIGS. 2 and 3 are systematic explanatory diagrams showing a specific example of an apparatus for implementing the method of the present invention, and FIG. FIG. 5 is a graph showing the effect of adding a granulating agent, and FIG. 5 is a graph showing the effect of moisture in coal/oil mixed fuel on stability. 1...Wet mill, 2...Coal input pipe,
3... Water supply pipe, 5... Mixing tank, 6...
...Underwater granulation/deashing machine, 7...First solid-liquid separator, 8...Deashing coal/petroleum fuel tank, 1
0... Second solid-liquid separator, 1 1... Dehydrated cake (ash) extraction pipe, 12... Waste water extraction pipe,
13...Deashed coal/petroleum mixed fuel extraction pipe, 15
・・・・・・Ferry plane, 16・・・・・・Heavy oil supply pipe, 1
7... Granulation agent supply pipe, 20... Rotating body, 21... Granulation section, 22... Separation section, 23... ...Mesh basket, 25...
Frame loss machine, 26... Heater, 27... Heavy oil supply V supply pipe, 30... Ash/wastewater extraction pipe, 31...
...Rotating body, 32...Smoke remover, 33...
...Discharge machine, 34...Ash/wastewater extraction pipe. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1 Coal and water are supplied to a wet mill, the coal is finely pulverized to prepare a coal/water slurry, and then this coal/water slurry is sent to a mixing tank together with heavy oil and a granulating agent for mixing. After that, this mixed slurry is sent to an underwater granulation/deashing machine, and a rotating body is rotated at high speed in the mixed slurry to granulate coal particles into pellets and separate the ash, and then the pellets and wastewater containing ash are separated. After separation, the pellets are sent to a deashed coal/petroleum fuel tank along with heavy oil to be heated and mixed to evaporate the moisture in the pellets, and the pellets are crushed to prepare a deashed coal/petroleum mixed fuel. Characteristic method for producing deashed coal/petroleum mixed fuel. 2. Coal and water are supplied to a wet mill and the coal is finely pulverized to prepare a coal/water slurry. This coal/water slurry is then sent to a mixing tank with heavy oil and a granulating agent for mixing, and this mixed slurry is The coal particles are sent to an underwater granulation/deashing machine, and multiple rotating bodies are rotated at high speed in the mixed slurry to granulate the coal particles into pellets and separate the ash content.Then, the pellets and ash are removed from the underwater granulation/deashing machine. The wastewater containing the pellets is extracted and sent to a first solid-liquid separator to be separated into pellets and wastewater containing ash, and the wastewater containing ash is further sent to a second solid-liquid separator to be separated into ash and wastewater. The pellets are recycled to the wet mill and reused as water for slurry preparation, while the separated pellets are fed to deashed coal and heavy oil along with heavy oil.
A method for producing a deashed coal/petroleum mixed fuel, which comprises feeding the pellets to a petroleum fuel tank, heating and mixing them to evaporate the moisture in the pellets, and crushing the pellets to prepare a deashed coal/petroleum mixed fuel. .