Multi-functional foam concentrate-type agent for inhibiting spontaneous ignition of soft coal

Abstract

The present invention relates to a multifunctional spontaneous combustion inhibitor for bituminous coal in the form of a foam concentrate, which may inhibit the spontaneous combustion of bituminous coal, prevent the scattering of bituminous coal, prevent the occurrence of problems due to spontaneous combustion, such as a power plant operation failure, bituminous coal waste, and odor generation, enables a bituminous coal power plant to be operated economically, safely and environmentally friendlily through the use of inexpensive bituminous coal, and may be used even at −20° C. by improving the pour point thereof. The present invention is characterized in that a spontaneous combustion inhibitor is prepared in the form of a water-soluble foam concentrate by using an antioxidant, a volatile fraction activation inhibitor, and an emulsifier compound, is mixed with water and air, and is distributed and applied to bituminous coal in a foamed state.

Claims

1. A multifunctional spontaneous combustion inhibitor prepared in a form of a foam concentrate, which is configured such that it is sprayed together with water and air and distributed and applied to bituminous coal in a foamed state, the spontaneous combustion inhibitor being prepared by mixing 7 to 13 wt % of an antioxidant, 20 to 40 wt % of a volatile matter activation inhibitor, 20 to 40 wt % of an emulsifier compound, and 20 to 40 wt % of water, wherein the antioxidant in the spontaneous combustion inhibitor comprises phenylenediamine.

2. A multifunctional spontaneous combustion inhibitor prepared in a form of a foam concentrate, which is configured such that it is sprayed together with water and air and distributed and applied to bituminous coal in a foamed state, the spontaneous combustion inhibitor being prepared by mixing 7 to 13 wt % of an antioxidant, 20 to 40 wt % of a volatile matter activation inhibitor, 20 to 40 wt % of an emulsifier compound, and 20 to 40 wt % of water, wherein the volatile matter activation inhibitor in the spontaneous combustion inhibitor comprises methyldiethanolamine (MDEA).

3. A multifunctional spontaneous combustion inhibitor prepared in a form of a foam concentrate, which is configured such that it is sprayed together with water and air and distributed and applied to bituminous coal in a foamed state, the spontaneous combustion inhibitor being prepared by mixing 7 to 13 wt % of an antioxidant, 20 to 40 wt % of a volatile matter activation inhibitor, 20 to 40 wt % of an emulsifier compound, and 20 to 40 wt % of water, wherein the emulsifier compound in the spontaneous combustion inhibitor comprises 25 to 40 wt % of butyl diglycol, 2 to 10 wt % of glycol ether, 3 to 10 wt % of a nonionic surfactant, and 45 to 65 wt % of a castor oil-based emulsifier.

Description

MODE FOR INVENTION

(1) A spontaneous combustion inhibitor for bituminous coal in the form of a foam concentrate according to the present invention is characterized in that it is prepared in the form of a foam concentrate, is sprayed together with water and air, and is distributed and applied to bituminous coal in a foamed state.

(2) The foam concentrate refers to a water-soluble functional chemical (product) that generates foam by mixing with water, and the foamed state refers to foam (bubble) that is generated when the spontaneous combustion inhibitor prepared in the form of a water-soluble foam concentrate is mixed with water. The spontaneous combustion inhibitor for bituminous coal according to the present invention should be a product in the form of a water-soluble foam concentrate so that an aqueous solution of the spontaneous combustion inhibitor may be prepared by mixing with water. In this case, the spontaneous combustion inhibitor may be expanded to a volume corresponding to the expansion rate thereof, and thus may be evenly distributed and applied to a large amount of bituminous coal in a foamed state.

(3) In this case, the reason for emphasizing water solubility is that it is important to sufficiently mix the core component of the spontaneous combustion inhibitor with water. That is, the reason is that, when the spontaneous combustion inhibitor is sufficiently mixed with water, it may be evenly distributed and applied to a large amount of bituminous coal, and only in this case, may exhibit its effects.

(4) In the present invention, the reason why the spontaneous combustion inhibitor is prepared in the form of a foam concentrate as described above is to evenly distribute and apply an appropriate concentration (ppm) of the core component of the spontaneous combustion inhibitor to the whole of bituminous coal, if possible. Even if a spontaneous combustion inhibitor has excellent performance, when it is not prepared in the form of a foam concentrate, 4 liters of an aqueous solution of the spontaneous combustion inhibitor cannot be evenly applied to 1,000 kg of bituminous coal. Accordingly, in order to effectively apply the spontaneous combustion inhibitor to a large amount of bituminous coal, it is inevitable to apply the spontaneous combustion inhibitor in a foamed state. To this end, the spontaneous combustion inhibitor is prepared in the form of a foam concentrate that is expanded about 10 times. In this case, according to the present invention, when 4 liters of an aqueous solution of the spontaneous combustion inhibitor is sprayed in a foamed state, the amount of foam generated becomes 40 liters. Thus, 40 liters of the spontaneous combustion inhibitor prepared as foam may be distributed and applied to 1,000 kg of bituminous coal.

(5) Preferably, 4 wt % of the spontaneous combustion inhibitor prepared in the form of a foam concentrate is mixed with 96 wt % of water, and distributed and applied to bituminous coal in a foamed state. If the amount of the spontaneous combustion inhibitor is less than 4 wt %, the spontaneous combustion inhibitory ability of the spontaneous combustion inhibitor will decrease, and if the amount is more than 4 wt %, the quality of the spontaneous combustion inhibitor will be lowered. That is, in a preferred embodiment, 4 wt % of the spontaneous combustion inhibitor is mixed with 96 wt % of water, and the mixture is evenly distributed and applied to bituminous coal in a foamed state by means of three or more foam nozzles in a conveyor belt system.

(6) Here, the spontaneous combustion inhibitor according to the present invention is mixed with water for the purpose of easily generating foam. When the spontaneous combustion inhibitor is mixed with water and air, foam is generated more easily, whereby the spontaneous combustion inhibitor may be evenly distributed and applied to bituminous coal. That is, even when the spontaneous combustion inhibitor is not artificially mixed with air, there is no problem in generating foam, because water is supplied by hydraulic pressure and air is mixed with water within the expansion rate of foam. However, in order to generate and maintain better foam in a better manner, air is preferably mixed with the spontaneous combustion inhibitor through a compressor or the like.

(7) In this case, the mixing ratio between an aqueous solution of the spontaneous combustion inhibitor and air is preferably 1:10. As described above, even when air is not mixed with the spontaneous combustion inhibitor through a compressor, it is possible to spray the spontaneous combustion inhibitor in a foamed form. However, in the present invention, the spontaneous combustion inhibitor is mixed with air so that all bituminous coal introduced into the indoor coal storage yard can be showered with foam, whereby the spontaneous combustion inhibitor can be evenly distributed and applied to the bituminous coal.

(8) As described above, when the spontaneous combustion inhibitor prepared in the form of a foam concentrate is mixed with water and air and evenly distributed and applied to bituminous coal in a foamed state, it prevents the scattering of dust from the bituminous coal and, at the same time, contributes to the prevention of oxidation, the inhibition of activation of volatile matter, the inhibition of dust generation, the inhibition of temperature rise, and prevents humidity from dropping, thereby inhibiting the spontaneous combustion of the bituminous coal before the bituminous coal in the carbon storage yard moves to a combustion chamber.

(9) According to an embodiment of the present invention, the spontaneous combustion inhibitor may be prepared by mixing 7 to 13 wt % of an antioxidant, 20 to 40 wt % of a volatile matter activation inhibitor, 20 to 40 wt % of an emulsifier compound, and 20 to 40 wt % of water.

(10) The antioxidant functions to inhibit bituminous coal from absorbing oxygen from air or water, thereby inhibiting the spontaneous combustion of the bituminous coal. The antioxidant is preferably contained in an amount of 7 to 13 wt % based on the total weight of the spontaneous combustion inhibitor. If the content of the antioxidant is less than 7 wt %, the antioxidant stability of the spontaneous combustion inhibitor may decrease, and if the content of the antioxidant is more than 13 wt %, the quality of the spontaneous combustion inhibitor may be degraded.

(11) The volatile matter activation inhibitor functions to inhibit the activation of volatile matter in bituminous coal, thereby inhibiting the spontaneous combustion of the bituminous coal. The volatile matter activation inhibitor is preferably contained in an amount of 20 to 40 wt % based on the total weight of the spontaneous combustion inhibitor. If the content of the volatile matter activation inhibitor is less than 20 wt %, the spontaneous combustion inhibitory ability of the spontaneous combustion inhibitor may decrease, and if the content of the volatile matter activation inhibitor is more than 40 wt %, the quality of the spontaneous combustion inhibitor may be degraded.

(12) The spontaneous combustion inhibitor for bituminous coal is prepared in the foam of a water-soluble foam concentrate using the antioxidant, the volatile matter activation inhibitor and the emulsifier components as main components. The spontaneous combustion inhibitor prepared in the form of a water-soluble foam concentrate is mixed with water and air without an anti-scattering agent and is evenly distributed and applied to bituminous coal in a foamed state, thereby preventing the spontaneous combustion of the bituminous coal and preventing the scattering thereof.

(13) The emulsifier compound contained in the spontaneous combustion inhibitor functions not only to enhance the emulsifying and dispersing ability of the spontaneous combustion inhibitor, but also to reduce the surface tension of water, so that the spontaneous combustion inhibitor may be distributed and applied to bituminous coal in a foamed state. In addition, the emulsifier compound also functions to prevent the scattering of dust. The emulsifier compound is preferably contained in an amount of 20 to 40 wt % based on the total weight of the spontaneous combustion inhibitor. If the content of the emulsifier compound is less than 20 wt %, the emulsifying and dispersing ability may decrease, and if the content of the emulsifier compound is more than 40 wt %, foam may be excessively generated, and thus the dispersibility and applicability of the spontaneous combustion inhibitor may decrease and the pour point of the spontaneous combustion inhibitor may increase, resulting in a decrease in the ease of use.

(14) In addition, the emulsifier compound contained in the spontaneous combustion inhibitor contains a solvent and a solubilizer, and thus functions to lower the viscosity of spontaneous combustion inhibitor, increase the bonding force between the components of the spontaneous combustion inhibitor, increase the service life of the spontaneous combustion inhibitor, and increase the efficiency of drying (water removal).

(15) The antioxidant contained in the spontaneous combustion inhibitor according to an embodiment of the present invention may comprise phenylenediamine that prevents the oxidation of bituminous coal. In this case, since phenylenediamine, which is used as the antioxidant in the spontaneous combustion inhibitor, is stabilized by resonance, it has very high antioxidant activity and in particular, improves the antioxidant stability of the spontaneous combustion inhibitor. Therefore, the phenylenediamine of the present invention may be advantageously used as an antioxidant compound, which is an additive for delaying the oxidative decomposition of the spontaneous combustion inhibitor and further improving the antioxidant stability thereof.

(16) According to an embodiment of the present invention, the volatile matter activation inhibitor in the spontaneous combustion inhibitor may comprise methyldiethanolamine (MDEA) that inhibits the activation of volatile matter. In this case, methyldiethanolamine that is used as the volatile matter activation inhibitor in the spontaneous combustion inhibitor functions as a base catalyst through a hydration reaction with water. This methyldiethanolamine has strong resistance to deterioration and corrosion, and may be effectively used as a volatile matter activation inhibitor that inhibits the activation of volatile matter having a low flash point, due to the characteristics thereof, such as high boiling point and low vapor pressure. In this case, the pour point of the spontaneous combustion inhibitor is naturally improved as methyldiethanolamine (MDEA) is used as a main raw material, the spontaneous combustion inhibitor may be used even at −20° C. or below. Thus, the ease of use of the spontaneous combustion inhibitor may be improved and at the same time, the necessity of providing a thermal insulation facility to a bituminous coal storage tank in terms of equipment is eliminated.

(17) According to an embodiment of the present invention, the emulsifier compound in the spontaneous combustion inhibitor may comprise 25 to 40 wt % of butyl diglycol, 2 to 10 wt % of glycol ether, 3 to 10 wt % of a nonionic surfactant, and 45 to 65 wt % of a castor oil-based emulsifier.

(18) The butyl diglycol is used as a basic emulsifier because of its excellent emulsifying properties, low volatility and high boiling point. The butyl diglycol is preferably contained in an amount of 25 to 40 wt % based on the total weight of the emulsifier compound. If the content of the butyl diglycol is more than 25 wt %, the emulsifying property of the emulsifier compound may decrease, and if the content of the butyl diglycol is more than 40 wt %, the quality of the emulsifier compound may be degraded.

(19) The glycol ether is effectively used as a solvent for emulsifying the antioxidant that is difficult to emulsify. The glycol ether is preferably contained in an amount of 2 to 10 wt % based on 100 parts by weight of the emulsifier compound. If the content of the glycol ether is less than 2 wt %, the effect of the solvent may decrease, and if the content of the glycol ether is more than 10 wt %, the quality of the emulsifier compound may be degraded.

(20) The nonionic surfactant is used as a surfactant because of its excellent solubility and stability for an alkaline mixture. The nonionic surfactant is contained in an amount of 3 to 10 wt % based on the total weight of the emulsifier compound. If the content of the nonionic surfactant is less than 3 wt %, the solubility and stability of the emulsifier compound may decrease, and if the content of the nonionic surfactant is more than 10 wt %, the quality of the emulsifier compound may be degraded.

(21) The castor oil-based emulsifier has excellent dispersibility and foaming power and is used as a solubilizer and surfactant for complete dissolution of the antioxidant together with the glycol ether. The castor oil-based emulsifier is preferably contained in an amount of 45 to 65 wt % based on the total weight of the emulsifier compound. If the content of the castor oil-based emulsifier is less than 45 wt %, the dispersibility and foaming power of the emulsifier compound may decrease, and if the content of the castor oil-based emulsifier is more than 65 wt %, the quality of the emulsifier compound may be degraded.

(22) <Evaluation of Spontaneous Combustion Inhibitory Ability>

(23) To evaluate the spontaneous combustion inhibitory ability of a spontaneous combustion inhibitor aqueous solution prepared according to the present invention, 1 kg of bituminous coal being actually used was placed in a container, 4 ml of the spontaneous combustion inhibitor aqueous solution was sprayed onto the bituminous coal. Then, the bituminous coal was heated to 100° C., and toxic gases generated by activation of volatile matter were captured and measured.

(24) In addition, for a comparative experiment, 1 kg of bituminous coal was placed in the same container without spraying the spontaneous combustion inhibitor aqueous solution (4 mg) prepared according to the present invention. Then, the bituminous coal was heated to 100° C., and toxic gases generated by activation of volatile matter were captured and measured.

(25) As a result of the measurement, it was confirmed that the amount of toxic gases generated from the bituminous coal onto which the spontaneous combustion inhibitor aqueous solution of the present invention was sprayed was smaller than the amount of toxic gases generated from the bituminous coal onto which the spontaneous combustion inhibitor aqueous solution was not sprayed. Thereby, it could be seen that the spontaneous combustion inhibitor of the present invention may exhibit excellent spontaneous combustion inhibitory properties by inhibiting the activation of volatile matter at a temperature of 100° C. or below and preventing oxidation.

(26) Therefore, the present invention has an advantage in that, because the spontaneous combustion inhibitor is prepared in the form of a water-soluble foam concentrate using the antioxidant, the volatile matter activation inhibitor and the emulsifier compound, the spontaneous combustion inhibitor prepared in the form of a water-soluble foam concentrate without an anti-scattering agent may be mixed with water and air and evenly distributed and applied to bituminous coal in a foamed state in a conveyor belt system, thereby inhibiting the spontaneous combustion of the bituminous coal while preventing the scattering thereof.

(27) In addition, the present invention has an advantage in that, because spontaneous combination of bituminous coal may be inhibited by distributing and applying an aqueous solution of the spontaneous combustion inhibitor to the bituminous coal, it is possible to prevent the occurrence of problems particularly due to spontaneous combustion, such as power plant operation failure, bituminous coal waste and odor generation.

(28) In addition, the present invention has an advantage in that, since the spontaneous combustion inhibitor may inhibit the spontaneous combustion of bituminous coal and, at the same time, prevent the scattering thereof, it is possible to operate a bituminous coal power plant economically, safely and environmentally friendlily through the use of inexpensive bituminous coal.

(29) In addition, the present invention has an advantage in that it is possible to prepare a spontaneous combustion inhibitor capable of inhibiting the spontaneous combustion of bituminous coal in a simple and economic manner.

(30) In addition, the present invention has an advantage in that, since the pour point of the spontaneous combustion inhibitor is also naturally improved by methyldiethanolamine (MDEA) contained in the spontaneous combustion inhibitor, so that the spontaneous combustion inhibitor may be used even at −20° C. or below, the ease of use of the spontaneous combustion inhibitor may be improved and at the same time, the necessity of providing a thermal insulation facility to a bituminous coal storage tank in tams of equipment is eliminated.

(31) In addition, the present invention has an advantage in that, since the spontaneous combustion inhibitor contains a sufficient amount of the emulsifier compound, it does not need to contain a separate anti-scattering agent for spraying the spontaneous combustion inhibitor in a foamed state, and thus has an economic effect in terms of equipment and maintenance costs.