JP5643967B2 - Method for preventing spontaneous combustion / dust generation of coal pile at coal storage and coal blended fuel - Google Patents

Description

  The present invention relates to a method for preventing spontaneous combustion and dust generation of a coal pile in a coal storage yard, and a coal mixed fuel. More specifically, in coal piles piled up in coal storage stations such as power plants, steelworks, mines, etc., a method for preventing spontaneous ignition and dust generation due to heat generated by an oxidation reaction in which coal absorbs oxygen in the air, and coal mixing Regarding fuel.

  In recent years, about 45% of the fuel used in thermal power plants in operation is coal, and the rest is LNG and oil. In a power plant, etc., the coal is piled up and stored in the coal storage until it is used as fuel after it is carried. During the storage, dust is caused by the wind, causing dust pollution to the surrounding area and loss of sediment. When the water content in the sediment becomes excessive, there is a disadvantage in that when this is burned, the heat of evaporation of water is caused. In addition, when coal piles are left for a long period of time, the heat energy increases with the storage period due to the oxidation reaction between oxygen in the air and hydrocarbons, carbon substances, or sulfur with high activity in the coal, and the heat generated at that time. Eventually, it will spontaneously ignite. In general, subbituminous coal with a low degree of carbonization and high volatility, or coal with high sulfur content, tends to generate heat due to long-term coal storage, and if it is neglected in temperature control, it tends to spontaneously ignite. The heat generated with the danger of such an ignition of the coal pile is a serious safety issue, and the quality of the coal itself is deteriorated even before spontaneous ignition is reached. Has been proposed.

  For example, a method of preventing the outside air and moisture from entering the coal bed by spraying a coating agent on the surface of the coal pile, a method of spraying latex (Patent Documents 1 and 2), spraying cement and resin or various resin liquids Coal quality deterioration prevention method (Patent Documents 8 and 9) or resin emulsion using a method (Patent Documents 3 to 7), a method of blowing an inert gas, pressurizing and fastening the surface of a coal pile, and a resin agent spraying method (Patent Documents 10 to 12) by combination with other chemicals, a method of coating low-ignition coal on a coal pile of high-ignition coal (Patent Document 13), and other sprinkling methods for sprinkling water from the surface of piled coal Or measures such as an injection method in which pressure water is injected into the coal seam have been taken.

Japanese Patent Publication No.53-38082 JP 2005-105029 A Japanese Patent Publication No. 60-54349 Japanese Examined Patent Publication No. 62-12122 Japanese Patent Publication No.62-25561 Japanese Examined Patent Publication No. 6-62974 JP 2000-80355 A Japanese Examined Patent Publication No. 4-53766 Japanese Examined Patent Publication No. 6-41324 JP 2000-80355 A JP 2000-96039 A JP 2002-20769 A JP 2004-292487 A

However, the above conventional techniques have the following problems.
In the method of spraying latex, cement and resin or various resin liquids as a coating agent on the piled coal pile surface, the coating strength and uniformity are easily affected by the weather when forming the coating, and the formed coating is Due to the sinking of the coal mine due to its own weight, the surface of the coal mine was distorted, and the coating could not follow this, resulting in the rupture (cracking) of the coating. For this reason, it is difficult to block outside air and moisture by the coating, and there is a problem that the effect is poor for the cost.
In recent years, the use of low-grade coal with a high volatile content has increased. High VM (Volatile Matter) coal has a problem that it easily causes an oxidation reaction with oxygen in the air and easily ignites spontaneously.
Furthermore, the watering method and the injection method are the simplest methods and preferable in terms of cost. However, excessively moistened coal has problems in terms of storage, transportation, and post-treatment. There is a limit, and as a result, long-term effects cannot be expected. Of course, excessive moisture has the problem of reducing combustion efficiency when coal is used as fuel.

  In addition, surfactants that are usually introduced to ensure the affinity with coal and prevent spontaneous ignition are added to the spraying liquid on the coal pile. However, surfactants are expensive. At the same time, it becomes a hindrance to the turbidity reduction operation during the drainage treatment of surplus water generated by sprinkling, and the load on the environment is large. If it is not carried out, it has a problem in terms of cost and equipment that it cannot drain.

The present invention solves the above-mentioned conventional problems, and by spraying a spray liquid containing algae on the surface of the coal pile with the surface of the coal pile or the chute of the transit building of the lifting coal facility, the surface of the coal The algae attached to the water and the water in the spray liquid suppress the air flow to the coal pile, prevent the coal from oxidizing, prevent quality deterioration and spontaneous ignition, and also prevent dust generation It aims at providing the prevention method of spontaneous ignition and dust generation of coal pile.
In addition, it was found that algae has a higher carbon content as much as there are more lipids, and its calorific value is 70-90% that of coal. Since woody biomass is about 60%, it has a higher amount of heat than woody biomass.
Therefore, algae is mixed and sprayed in the spraying liquid sprayed on the coal pile, preventing oxidation of the coal pile, and at the same time, drying using the heat energy generated by the oxidation of the coal and co-firing with coal as biomass fuel The purpose of this is to achieve carbon neutralization, reduce carbon dioxide in coal-fired power plants and factories, and provide coal-mixed fuel that helps prevent global warming.

In order to achieve the above object, the present invention has the following configuration.
According to a first aspect of the present invention is the concentration of 0.5 million in to 1 × 10 ⁵ million cells / mL of algae contained in the spray solution to watering coal pile coal yard, carbon of the algae The content is 30% or more .
This configuration has the following effects.
(1) Since algae has a large amount of lipids, it has a high carbon content and a calorific value of 80% or more of the caloric value of coal, so it has co-firing properties with coal as a fuel.
(2) Since it has co-firing property, carbon neutral can be achieved by the amount of co-firing, contributing to the reduction of carbon dioxide and excellent resource saving.
(3) Algae in the spray liquid has a high water content (about 65%), excellent cooling effect, and strong adhesion to lipophilic coal, so that it adheres to the surface of coal such as coal piles. A film can be formed.
(4) Since an algae coating layer is formed on the surface of the coal pile, it is possible to prevent the oxidation of the coal, inhibit the air flow to the inside of the coal pile, particularly the middle portion, and suppress the oxidation reaction of the coal inside. Can prevent spontaneous ignition.
(5) Since the concentration of the algae in the spray liquid is sprayed at 5,000-1 × 10 ⁵ 000 cells / mL, the coal is pulverized with a mill together with the algae attached to the coal (attachment rate: 10-50%). However, it does not impair the grindability and is excellent in handleability as a mixed fuel with coal.
(6) Although the oxidation reaction of coal is most likely to occur at a height in the vicinity of the middle between the top and bottom of the coal pile, the algae previously sprayed with the spray solution sprayed on the top of the coal pile peels off from the surface of the coal. However, due to the adherence and viscosity of the algae, a large amount of algae are present even near the middle, preventing oxidation and preventing the coal from being heated by the water contained therein, thereby preventing spontaneous ignition.
(7) Since the coal is black, the amount of radiant heat from the sun is easily absorbed as a large amount of heat, but the algae on the surface of the coal pile can absorb the radiant heat and reduce the amount of heat absorbed by the coal.
(8) Since the coal is prevented from being oxidized, quality deterioration (loss of calorific value) can be prevented and resource saving can be achieved.
(9) As it goes into the inside of the coal pile, the algae that have not adhered and the algae that have peeled off fill the gaps between the massive coals, so that air permeability can be inhibited.
(10) Since the length and width of the algae are small, the algae penetrate into the pores of the lipophilic coal, so that oxygen diffusion into the coal can be blocked. In addition, algae are lipophilic, and the algae itself is as small as several tens of microns, so it has excellent diffusibility inside the coal pile.
(11) Since the carbon content is high, it can be used as an alternative fuel for coal, and the amount of coal used can be reduced correspondingly, resulting in excellent resource saving and carbon neutral.

  Here, the coal of the coal pile covers bituminous coal, subbituminous coal, lignite, anthracite, modified coal, and the like. As the spray liquid, industrial water or reused water from coal storage wastewater can be used.

Spraying starts when the temperature of the coal pile rises. Pile ignition occurs when the temperature inside the pile rises and air reaches that part. Expect to reduce temperature in sprinkling. The mixing of the algae into the spray liquid can improve the cooling efficiency as well as the cooling effect, the effect of inhibiting the diffusion of air into the coal pile, and the algae staying on the coal surface and drying.
In the spray solution, when thiourea, nitrite compound, bicarbonate compound, ammonium phosphate salt compound, one or more selected from the group of water-absorbing polymer is contained as an additive in an amount of 15% by weight or less, Various effects are taken into account, and spontaneous combustion can be effectively prevented or suppressed in coal. The main effects of these components are thiourea and nitrite compounds to prevent oxidation, bicarbonate compounds to generate carbon dioxide when exothermic, ammonium phosphate salt compounds to provide flame retardancy, and water-absorbing polymers to retain water. Has an improving effect.

  When the spray liquid contains a polyol compound and / or a water-soluble surfactant having a molecular weight of 1000 or less and a valence of 2 or less, the wettability and permeability of the coal surface can be improved.

As algae, spirulina, schizon, gardi area, euglena, botryococcus, chlorella, desmodesmus and the like are preferably used.
This is because these algae have excellent adhesion to coal, and the spray solution containing algae has high wettability to the surface of lipophilic coal and can increase spray efficiency.
Furthermore, the carbon content at the time of drying is as high as about 40 to 51%, the amount of heat is the same as that of coal, and co-firing can be performed with a boiler. Moreover, it is because the self-propagation rate is high, resources can be used, and energy saving is excellent.
Furthermore, since it is excellent in acid resistance, it is easy to adapt to the exhaust gas after desulfurization of a coal-fired power plant, and the construction and operation of a carbon dioxide absorption system containing a medium is easy and excellent in labor saving.
The concentration of algae, 0.5 million in to 1 × 10 ⁵ million cells / mL is used. Preferably, the viscosity of the spray water tends to decrease as the concentration decreases from 50,000 cells / mL, and the viscosity of the spray water tends to increase as the concentration increases from 1 × 10 ⁵ 000 cells / mL. Absent.
The counting of the number of cells at the algal concentration is preferably carried out using a Toma hemocytometer or a Birkelturk hemocytometer.
As for the type having a small number of cells and the type of colony, 3.0 × 3.0 × 0.1 mm was counted with Birkelturk. As the number of cells increases, it is necessary to reduce the number of cells to be counted so that the number of counts does not become excessive.
When the number of cells is 10,000 cells / mL or more at the initial concentration, 1.0 × 1.0 × 0.1 mm is counted with a toma.
For the concentration of algae, a solid-liquid separation method such as a centrifugal separation method is used.
Algae absorb a lot of carbon dioxide during growth, which contributes to reducing greenhouse gas emissions at power plants.
By mixing it in the spraying liquid at the coal storage, the algae are automatically dried and mixed with the coal, so that it can be used as biomass fuel without modifying the equipment.
Usually, when using algae, there are many examples of separating and using the oil to be stored by drying and compressing, but it can be used simply by drying at the coal storage, so it needs to be processed for use as energy Less man-hours and labor saving.

According to a second aspect of the present invention, in the method for preventing spontaneous combustion and dust generation of coal piles in the coal storage yard according to the first aspect, when the bulk coal is transferred and / or deposited, It has an intermediate spraying step of wetting the surface with a spray solution containing the algae, and a pile spraying step of spraying the spray solution containing the algae on the pile when the temperature of the coal pile rises. .
With this configuration, in addition to the operation obtained in the first aspect, the following operation can be obtained.
(1) In the intermediate spraying process, the sprayed liquid is sprayed on the surface of the coal pile that is being deposited or on the surface of the coal by using the chute of the transit building of the unloading coal facility. It can be made easy to adhere and fix to. Since the spray liquid is sprayed during deposition, algae are mixed inside the coal pile, the surface of the coal is covered with the adhesion and viscosity of the algae, the contact area with air is reduced, and the coal containing the algae contains water. Can be cooled to prevent spontaneous ignition.
(2) Biomass fuel can be automatically mixed with coal in the pile watering process.

Here, in the pile spraying step, the number of spraying is appropriately changed according to the algae coating state on the surface of the coal pile and the temperature in the dry state pile. Moreover, when there is a lot of rainfall, intermediate spraying and pile spraying are not performed.
Also, in the intermediate spraying process, increasing the spraying amount inside the coal pile, that is, the part where heat generation is expected in the middle part, increases the water retention capacity of the coal pile and prevents oxidative degradation of the coal, thereby spontaneously igniting the coal. Can be effectively prevented.
Since algae have a cell wall, the water content in the cytoplasm is retained, so that a water retention effect higher than that of the conventional spray liquid can be obtained. Algae lose their physiological activity when adsorbed to the exothermic coal, but they can prevent the diffusion of air into the interior by filling the pores of the coal and the gaps between the coals. Moreover, even after the algae dies, the oil can effectively function to prevent spontaneous ignition by coating the coal surface.

The additive thiourea is not particularly limited, and examples of the nitrite compound include NaNO ₂ , KNO _{2, and the} like, and all have an antioxidant effect.
Examples of the bicarbonate compound include NaHCO ₃ , KHCO _{3 and the} like, and serve as a carbon dioxide gas generation source during heat generation.
Examples of the ammonium phosphate compound include NH ₄ H ₂ PO ₄ , (NH ₄ ) ₂ HPO _{4 and the} like, and a flame retardant effect is achieved.
These compounds can be used in the form of powder mixed with urea powder, or dissolved or dispersed in an aqueous urea solution.
Examples of the water-absorbing polymer component include polyacrylates, polysulfonates, and polyvinyl alcohol / polyacrylate copolymers. In addition, starch-based and cellulose-based polymers include graft polymerization and carboxymethylation, respectively. There is.
This water-absorbing polymer has an effect of improving water retention, and can be used after being mixed with a powder containing urea powder as a main component in a powdered or granular form, or added to a urea aqueous solution and moistened. However, it is preferable to use it in a powdery or granular form.
Furthermore, by including 15% by weight or less of a polyol compound and / or a water-soluble surfactant having a molecular weight of 1000 or less and having a valence of 2 or more, the wettability, permeability and moisture retention of the coal surface can be improved.
Among the above components, examples of the polyol compound include monoethylene glycol, propylene glycol, diethylene glycol, glycerin, polyglycerin (molecular weight 1000 or less), polyvinyl alcohol (molecular weight 1000 or less), and the like.
Examples of water-soluble surfactants include alkyl allyl sulfonate, alkyl sulfate ester salt, polyoxyethylene alkyl ether acetate salt, dialkyl sulfosuccinate, polyoxyethylene alkyl sulfate ester salt, and polyoxyethylene phosphate ester salt. Nonionic surfactants such as anionic surfactants, polyoxyethylene alkyl ethers, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, higher fatty acid glycerin esters, polyoxyethylene alkylamines, alkylolamides are exemplified. The

The invention according to claim 3 of the present invention is the method for preventing spontaneous ignition and dust generation of coal piles in coal mine according to claim 1 or 2, wherein the algae are cyanobacteria, red algae, euglena algae, green algae. The configuration is as described above.
With this configuration, in addition to the operation obtained in the first or second aspect, the following operation can be obtained.
(1) Since these algae are generally easily available and have excellent growth ability, resources can be saved by the amount used as fuel.
(2) Since the lipid content is generally large, a large calorific value is obtained by co-firing with coal, and energy saving is excellent.
(3) Since the oil can prevent direct contact between coal and air (oxygen) even after the algae dies, quality deterioration of the coal can be prevented.
(4) Since carbon dioxide is used for the growth of the algae used, for example, if carbon dioxide in the exhaust gas from the power plant is used, it can contribute to the reduction of the greenhouse effect.
Here, these algae are preferably freshwater algae. This is because it is neutral, so that it does not corrode coal combustion equipment.

According to a fourth aspect of the present invention, in the method for preventing spontaneous combustion and dust generation of a coal pile in a coal storage yard according to any one of the first to third aspects, the algae is a Spirulina spp. It has a configuration comprising one or more of the genus Anidiosison, Gardieria, Euglena, Botryoyuccus, Chlorella, and Desmodemus.
With this configuration, in addition to the actions obtained in claims 1 to 3, the following actions are obtained.
(1) Since it has a high carbon content and is excellent in fuel suitability, it can be co-fired with coal in a boiler, and backfire hardly occurs when co-fired.
(2) Since it is excellent in acid resistance, it is excellent in the tolerance to the aqueous solution which absorbed the carbon dioxide of the exhaust gas of a coal combustion boiler.
(3) By using unicellular algae, asexual reproduction is possible and it can be easily propagated even in a medium in a power plant or factory.

According to a fifth aspect of the present invention, in the method for preventing spontaneous combustion and dust generation of a coal pile in a coal mine according to any one of the first to fourth aspects, the alga has a pH of 1 to 5. It has a structure resistant to sulfuric acid and nitric acid .
With this configuration, in addition to the actions obtained in claims 1 to 4 , the following actions are obtained.
(1) Since it is excellent in acid resistance, the exhaust gas treatment solution of a coal boiler such as a coal-fired power plant can be used as an algae culture solution.
(2) By using the exhaust gas treatment liquid, it is possible to automatically absorb carbon dioxide in the exhaust gas and reduce the discharge amount to the atmosphere.

Here, when using the exhaust gas treatment liquid of a coal thermal power plant as a culture solution, the culture solution which absorbed the exhaust gas desulfurized with the flue gas desulfurization apparatus is used. The flue gas desulfurization apparatus desulfurizes by the following reaction (Formula 1).
In order to dissolve the exhaust gas in water, the temperature of the exhaust gas is cooled to 40 ° C. to 50 ° C. in the absorption tower. This is because the SO _X concentration in the exhaust gas desulfurized by the flue gas desulfurization apparatus is about 30 to 50 ppm, and the pH drop of the culture solution can be prevented.

The invention according to claim 6 of the present invention is the method for preventing spontaneous combustion and dust generation of coal piles in coal storage according to any one of claims 1 to 5 , wherein the algae is 10% or more. The structure has resistance to air containing carbon dioxide .
With this configuration, in addition to the actions obtained in claims 1 to 5 , the following actions are obtained.
(1) Algae can grow even in a treatment solution having a carbon dioxide concentration in exhaust gas of 10 to 15%.
(2) High density growth is possible by having carbon dioxide resistance.

According to a seventh aspect of the present invention, in the method for preventing spontaneous combustion and dust generation of a coal pile in a coal storage yard according to any one of the first to sixth aspects, the algal growth rate is 2. It has the structure which is more than double / day.
With this configuration, in addition to the actions obtained in claims 1 to 6 , the following actions are obtained.
(1) More carbon dioxide can be absorbed and carbon neutral can be achieved accordingly.

The invention according to claim 8 of the present invention is the method for preventing spontaneous combustion and dust generation of coal piles in a coal mine according to any one of claims 1 to 7 , wherein the algae is added to the spray liquid. It has a configuration in which an adhesion assistant that improves adhesion is contained.
With this configuration, in addition to the actions obtained in claims 1 to 7 , the following actions are obtained.
(1) More algae can be attached and mixed in larger amounts.
(2) Since the air can be blocked more efficiently, the effect of preventing ignition is great.
(3) The effect of preventing scattering is high by increasing the adhesion.

Coal fuel mixture according to claim 9 of the present invention includes a coal bulk, a configuration and an algae carbon content of 30% or more adhering to the surface of the coal.
With this configuration, in addition to the actions obtained in claims 1 to 8 , the following actions are obtained.
(1) The amount of carbon neutral fuel can be increased by the amount of algae attached and co-fired.
(2) Algae has good adhesion to the coal surface, has a large spontaneous ignition prevention effect, and maintains quality because it is difficult to oxidize.

(A) Perspective view of heat insulation container part of coal heating experiment apparatus (b) AA line sectional view of FIG. Diagram showing cooling effect of spray liquid The figure which shows the result of acid resistance screening of Gardi area The figure which shows the result of the acid resistance screening of cyanidiosizone Figure showing the results of acid resistance screening of Spirulina Figure showing the results of Euglena acid resistance screening Diagram showing the results of acid resistance screening of Botryococcus Figure showing the results of chlorella acid resistance screening Figure showing the results of acid resistance screening of desmodesmus

  Hereinafter, the present invention will be specifically described by way of examples. The present invention is not limited to these examples.

1. Selection of algae As algae, we searched for algae applicable to the exhaust gas of coal-fired power plants, and obtained the following seven species shown in (Table 1).

2. Algae flammability (Experiment Nos. 1-7)
Each algae was cultured in a medium, each algae was collected, the carbon content was analyzed with a CHN coder, and the flammability was evaluated. The results are shown in (Table 2).
The carbon content was as high as 51% for Desmodesmus, 49% for Euglena and Botryococcus, and 43% for Gardi area. Botryococcus is a hydrocarbon-producing algae, and is known to have high oil content and carbon content, and excellent combustibility. It was found that flammability equivalent to Botryococcus was also expected for the other three types.

Next, the calories of algae and coal were compared.
Euglena was used as a sample. Euglena had a carbon content per dry weight of 49.1% and hydrogen of 7%.
The combustion heat of carbon is
394 KJ / mol = 394 KJ ÷ 4.19 (KJ / kcal) × 1 Kg / 12 g =
7,836 kcal / kg
The combustion heat of hydrogen is
286 KJ / mol = 286 KJ ÷ 4.19 (KJ / kcal) × 1 Kg / 2 g =
34,128 kcal / kg
The approximate amount of heat per kg dry yield of Euglena is
1kg × 49.1% × 7,836 kcal / kg = 3,847 kcal
1kg × 7% × 34,128kcal / kg = 2,389kcal
Therefore, 3,847 kcal + 2,389 kcal = 6,236 kcal / kg
The ratio with coal is
6,236 kcal / kg (euglena) ÷ 6,800 kcal / kg = 91.7%
From the above, it can be said that algae have approximately the same amount of heat as coal and can be co-fired with coal. In addition, it became clear that the amount of algae mixed with coal could save resources and achieve carbon neutrality.

3. Algae adhesion to coal (Experiment No. 8-16)
When an algae culture solution is sprayed on coal with high water repellency, algae in the culture solution may not adhere to the coal and may not be co-fired. Therefore, the purpose was to understand the adhesion rate of algae to coal.
3.1 Experimental method Algal culture solution was passed through a coal column, and the number of algal cells before and after passage was compared. Coal (Issack Plains) was 0.5 to 3 cm from which powder was removed by sieving with a 0.5 cm sieve.
As the coal column, an acrylic pipe having an inner diameter of 4.3 cm was used. In the experiment, the coal column was packed to a thickness of about 90 cm (the weight of the packed coal was about 1 kg).
Four types of the aforementioned spirulina, Euglena, Botryococcus, and Chlorella were used as algae, and 100 mL of each culture solution concentrated by centrifugation was poured into a coal column.
The number of cells before and after passing through the core was counted, and the adhesion rate of algae to coal was calculated. The number of cells was calculated by averaging nine counting results per sample and calculating the number of cells per mL.
The number of cells was counted using a Toma hemocytometer and a Birkelturk hemocytometer.
As for the type having a small number of cells and the type of colony, 3.0 × 3.0 × 0.1 mm was counted with Birkelturk.
For cells having an initial concentration of 10,000 cells / mL or more, 1.0 × 1.0 × 0.1 mm was counted with a toma.
3.2 Experimental Results The adhesion rate is 7 to 46%, and there is a possibility that algal cells themselves adhere to coal regardless of the type and concentration of algae. Table 3 shows the measurement results of the number of cells.

4). Direct observation of algae attached to coal (Experiment No. 17-20)
The adhesion of the algae to the heated coal was confirmed directly with a microscope. This is to confirm whether the algae adhere to the heated coal before the spontaneous combustion in the middle part of the coal pile and the algae adhere to it and can exhibit a cooling effect and an oxygen blocking effect.
4.1 Experimental Method A cross section of coal (particle size of about 3 cm) was polished with sandpaper (# 2000) and washed with water, and then heated at 100 ° C. for 30 minutes in a dry heat sterilizer. The heated coal was concentrated by centrifuging four types of culture solutions of Spirulina (Experiment No. 17), Euglena (Experiment No. 18), Botryococcus (Experiment No. 19), and Chlorella (Experiment No. 20). After dripping for 10 seconds in the spray solution composed of the concentrated solution (Experiment No. 8, 10, 12, 14), the algae attached to the polished surface of the coal were observed with an epifluorescence microscope.
4.2 Experimental results Spirulina (Experiment No. 17) hardly adhered.
Three types of Euglena (Experiment No. 18), Botryococcus (Experiment No. 19), and Chlorella (Experiment No. 20) had an increased number of attachments corresponding to the cell density.
From the above, it was confirmed that algae adhere to the coal surface regardless of the type and concentration of algae.

5. Wetability of algae culture (Experiment No. 21-30)
When the wettability of coal is increased by the algae culture solution, the amount of the surfactant currently used can be reduced, and the water treatment cost is reduced. Therefore, the smearability of the algae culture solution was examined.
5.1 Experimental Method After grinding and washing the cross section of coal (particle size of about 5 cm) with sandpaper (# 2000), four types of Spirulina, Euglena, Botryococcus and Chlorella shown in (Table 4) are centrifuged. 50 μL of each of the concentrated low-concentration culture solutions (Experiment Nos. 8, 10, 12, and 14) was dropped, and the contact angle of the water droplet was measured as an index of wettability. As a control, the contact angle of distilled water was also measured.
5.2 Experimental results In the case of the Botryococcus low concentration culture solution, the wettability increased. Only Botryococcus (low concentration) decreased water repellency. This is thought to be due to the oil discharged outside the cell. The concentration increased at a high concentration, but this is thought to be caused by discarding the supernatant containing oil by centrifugation.
Spirulina did not affect water repellency.
Chlorella and Euglena showed increased water repellency.
Table 4 shows the contact angle measurement results (average of three measurements).
As is apparent from the results of (Table 4), since the contact angle of Botryococcus can be reduced, the addition of the surfactant can be reduced and the load of water treatment can be reduced.

6). Cooling effect of spray liquid (Experiment No. 31)
When heat generation occurred in the lower part of the coal bed, the temperature change in the bed when the spray liquid containing algae was sprayed was verified.
6.1 Experimental method After using a coal bed heating experimental device to heat the heater with a predetermined amount of heat, a spray solution containing algae from the upper part of the coal bed [chlorella high-concentration solution, cell number: 9.19 million cells / mL] Sprayed. At this time, the temperature distribution in the coal bed was measured with thermocouples installed every 50 mm.
A coal bed heating experimental apparatus is shown in FIG.
In FIG. 1, 1 is a coal bed heating experimental apparatus, 2 is a heat insulating container, 3 is a coal bed stored in the heat insulating container 2, and 4 is a thermocouple inserted in the side wall of the heat insulating container 2 at equal intervals of 50 mm. Holes 5 are seven thermocouples a to g inserted from the thermocouple insertion hole 4 to the center of the coal bed, and 6 is a rubber heater installed at the bottom of the heat insulating container 2.
6.2 Experimental Results FIG. 2 shows the temperature response when the heating value of the heater is fixed at 4.6 W and 50 cc of the spray liquid is sprayed from the upper part of the coal bed.
Even with a slight spraying of 50 cc, the sprayed liquid flowed all the way down to the bottom of the coal bed, and the temperature of the thermocouple a in contact with the heater dropped rapidly. That is, the cooling effect of the heat source by the spray liquid was confirmed. In addition, because the heating value of the heater is maintained at 4.6 W, the temperature in the coal bed rises even after the algae is sprayed, but the temperature rise of the thermocouple a is suppressed due to the cold and moisturizing effect of the spray liquid. You can see that.
Since the spray liquid is mostly water, it can of course be expected to have an anti-inflammatory effect.

7). Effect on milling (Experiment No. 32-33)
In a coal boiler, coal is pulverized by a mill into “pulverized coal” of 0.3 mm square or less and burned in a burner portion in the boiler. Therefore, coal with algae biomass must be crushed. Therefore, the influence on the grindability due to the adhesion and mixing of algae was examined.
7.1 Experimental Method Prepare a coal-only (untreated) sample (Experiment No. 32) and a sample (Experiment No. 33) soaked in Euglena (approximately 0.5 g / L, approximately 1 million cells / mL). A pulverization experiment was conducted using a ball mill. The coal used 5 samples of 3-5g coal as 1 sample. As the ball mill balls, eight alumina balls having a diameter of 40 mm were used, and the state of the sample after 1, 2, and 3 hours after pulverization was confirmed.
Further, a crushing experiment was performed on the sample (Experiment No. 34) and the sample (Experiment No. 35) which were dried overnight by spraying algae using the above-described ball mill.
7.2 Experimental Results It was confirmed that for all samples, the surface of the coal was scraped over time and the amount of pulverized coal increased.
Experiment No. of the comparative example. 32 and Experiment No. In 33, there was almost no difference regarding the progress of pulverization.
Experiment No. was sprayed with algae and dried overnight. 34 and Experiment No. For 35 coals, experiment no. Similar results to 32 were obtained.
Judging from the results of this experiment, there was no effect on the coal grindability in the case of algae of about 0.5 g / L (about 1 million cells / mL in Euglena). For this reason, it was found that there was no problem in terms of pulverization when algae was sprayed on the coal storage.

8). Verification of acid resistance (Experiment No. 36-42)
8.1 Experimental Conditions Culture experiments under the conditions shown in (Table 5) were performed on seven species of algae.
The culture medium, pH, and initial cell concentration were set differently as shown in (Table 6). To each storage medium, an aqueous solution of sulfuric acid: nitric acid = 5: 3 (v: v) was added to adjust the pH. The water temperature was 37 ° C. for 2 types of hot spring isolation (cyanididizone, gardi area), 23 ° C. for the other 5 types, and pH was 1 to 5 for 2 types of hot spring isolation and 2 to 8 for the other 5 types.

8.2 Experimental Results The growth rate of freshwater algae at each pH is as shown in FIGS.
Two types of hot spring isolations grew to pH 1-5 as shown in FIGS. The growth rate is fast in the Gardi area. Among the other five species, Euglena grew to pH 3 and was excellent in acid resistance.

9. Verification of resistance to exhaust gas (Experiment No. 43, 44)
As a result of acid resistance screening, Gardi area and Euglena were selected and their resistance to carbon dioxide was verified.
9.1 Experimental Conditions Culture conditions in which air containing 100% carbon dioxide or 15% carbon dioxide was aerated were carried out under the experimental conditions shown in (Table 7) at a 1 L flask level, and the growth status was examined.

9.2 Experimental Results A 1 L flask level culture of Gardiarea and Euglena was performed, and the results shown in (Table 8) were obtained.
The Gardi area was found to withstand aeration of pH 1 and 100% carbon dioxide.
Euglena was resistant to aeration of pH 3 and carbon dioxide 15%, so it was considered that it could grow even during the aeration of coal exhaust gas. The growth rate was fast and the amount of biomass recovered was large.

  The present invention, by spraying the surface of the coal pile and the spray liquid containing algae on the surface of the coal with the chute of the transit building of the lifting coal facility, the algae attached to the surface of the coal and the water in the spray liquid In addition, it prevents air quality deterioration and spontaneous ignition by suppressing air flow to the coal pile and preventing coal oxidation. Providing a method, and mixing and spraying algae in the spray liquid sprayed on the coal pile, preventing oxidation of the coal pile, and simultaneously drying and co-firing using the heat energy generated by the oxidation of the coal To neutralize carbon, reduce carbon dioxide in coal-fired power plants and factories, and provide coal-mixed fuel that helps to prevent global warming. This enables coal storage in power plants, steelworks, mines, etc. Piled up on the ground In coal pile, coal can contribute to further resource saving can prevent spontaneous ignition or dust due to heat occurring in the oxidation reaction that absorbs oxygen in the air.

DESCRIPTION OF SYMBOLS 1 Coal bed heating experimental apparatus 2 Heat insulation container 3 Coal bed 4 Thermocouple insertion hole 5a-g Thermocouple 6 Rubber heater

Claims (9)

The concentration of algae contained in the spray solution to watering the coal storage coal pile was 0.5 million in to 1 × 10 ⁵ million cells / mL, and wherein the carbon content of the alga is 30% or more To prevent spontaneous combustion and dust generation of coal piles in the coal storage. When transferring and / or depositing bulk coal , an intermediate spraying step of wetting the surface of the coal with a spray liquid containing the algae, or spraying containing the algae on the pile when the temperature of the coal pile rises The method for preventing spontaneous combustion / dust generation of a coal pile in a coal storage yard according to claim 1, further comprising a pile spraying step of spraying a liquid .   3. The method for preventing spontaneous combustion / dust generation of a coal pile in a coal storage yard according to claim 1, wherein the algae is one or more of cyanobacteria, red algae, Euglena algae, and green algae.   The said algae consists of 1 or more in Spirulina genus, Cyanidiosizone genus, Gardieria genus, Euglena genus, Botryococcus genus, Chlorella genus, Desmodemus genus, The any one of Claims 1 thru | or 3 characterized by the above-mentioned. To prevent spontaneous combustion and dust generation of coal piles in coal mine storage areas. 5. The method for preventing spontaneous combustion / dust generation of coal piles in a coal storage yard according to any one of claims 1 to 4 , wherein the algae has resistance to sulfuric acid and nitric acid having a pH of 1 to 5. . The said algae has tolerance with respect to the air containing 10% or more of carbon dioxide , The self-ignition and dust generation of the coal pile of the coal storage ground of any one of Claim 1 thru | or 5 characterized by the above-mentioned. Prevention method. The method for preventing spontaneous combustion / dust generation of a coal pile in a coal storage yard according to any one of claims 1 to 6 , wherein the growth rate of the algae is twice or more per day. The spontaneous combustion / dust generation of a coal pile in a coal storage yard according to any one of claims 1 to 7 , wherein the spraying liquid contains an adhesion aid that improves adhesion of the algae. Prevention method. Coal mixed fuel, characterized in that it comprises a coal bulk, and a algae carbon content of 30% or more adhering to the surface of the coal.