JP2010138230A - Method for producing solid fuel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a method for efficiently treating an isocyanate process waste liquid independently and producing a solid fuel from the isocyanate process waste liquid, which is typically solidified and buried or directly incinerated in a conventional manner. <P>SOLUTION: In the method for producing the solid fuel by solidifying a liquid mixture obtained by adding the isocyanate process waste liquid (3) into a liquid comprising at least either water or polyol (2) while stirring (5) the liquid mixture, the solidification is performed in the presence of oil (1). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a solid fuel produced by solidifying an isocyanate process waste liquid in a mixed liquid of oil / water or polyol.

  A polyisocyanate compound having two or more isocyanate groups and a polyol compound having two or more hydroxyl groups react well to form a polyurethane resin. On the other hand, a compound having water and an isocyanate group produces a polyurea resin by a two-step reaction. First, a polyisocyanate compound and water react to produce polyamine and carbon dioxide. It is known that the polyamine produced here further reacts with a polyisocyanate compound to produce a polyurea resin having a urea bond.

  Polyurethane resins are used in paints, adhesives, textile products, automobile parts and the like. In addition, since the polyurea resin actually reacts a part of the isocyanate group of the isocyanate group-terminated prepolymer with a low-molecular polyol and the like, and then reacts the remainder of the isocyanate group with water, the name is called a polyurethaneurea resin. Is more accurate. Applications of this resin include, for example, powdered thermoplastic polyurethane urea resins with excellent mechanical properties, abrasion resistance, and melt moldability, and excellent re-peelability, transparency, and uniformity. It is a urea-based grease based on refined mineral oil with low adhesiveness and adhesive strength, and heat stability. In particular, since it is excellent in heat resistance and water resistance, it has a wide range of uses such as construction machinery, agricultural machinery, and industrial machinery, and is an industrially important resin material.

  As described above, it is a polyisocyanate used as a raw material for resin materials used in a wide range of applications, but various types of isocyanates are synthesized depending on the application of the resin to be produced. Typical examples include methylene diphenyl diisocyanate (MDI) and tolylene diisocyanate (TDI), which account for the majority of industrially produced isocyanates. These isocyanates are synthesized by the Curtius rearrangement of acid azide, the Loxen rearrangement of hydroxamic acid, and the like, but industrially synthesized mainly by the reaction (carbonylation) of amine and carbonyl chloride. From the synthesis process of polyisocyanate, polyisocyanate that has not reached a certain quality, isocyanate residue that remains without being distilled in the distillation step of the synthesis process, and the like are discharged as an isocyanate process waste liquid. As a treatment method for waste liquids composed of these miscellaneous isocyanate compounds (hereinafter referred to as isocyanate process waste liquids), incineration in a liquid state or after solidifying by reacting with moisture in the air, the landfill is performed. The main method was to incinerate. The following patent documents have been found as related technologies, but no method has been found for simply treating this isocyanate process waste liquid and effectively using it as a fuel.

  For example, as a method for treating an isocyanate process waste liquid, a mixed system of an isocyanate process waste liquid and an organic waste or an inorganic waste is obtained by urethanation with one or more of water, alcohol, and amine. Patent Document 1 proposes a waste treatment method characterized by solidifying a solid.

  Further, as a related technique, Patent Document 2 relating to a method for concentrating crude isocyanate has been found. In this document, a method for recovering isocyanate from a crude isocyanate concentrate by adding a principal amount of oil and an ashless dispersant to concentrated isocyanate and performing distillation is proposed.

JP2007-152266 (Claim 1) Patent 3001970 ([Claim 1] etc.)

  The purpose is to propose a method for efficiently treating an isocyanate process waste liquid that has been mainly solidified and landfilled or incinerated as it is, and producing solid fuel from the isocyanate process waste liquid. And

  As described above, conventionally, the isocyanate process waste liquid is mainly solidified and landfilled or incinerated as it is. In this case, the discharged isocyanate process waste liquid becomes totally trash, and the cost and energy required for incineration and disposal. There was a problem that could not be recovered. In addition, the applicant has proposed a related technique such as the above-mentioned Patent Document 1, but Patent Document 1 solidifies a combination of wastes containing a large amount of moisture such as silicon wafer polishing residue and doping sludge and isocyanate process waste liquid. Thus, the present invention is a waste treatment method that is different from the present invention that can efficiently treat an isocyanate process waste liquid alone. On the other hand, Patent Document 2 discloses a hardly soluble by-product (a relatively high molecular weight insoluble product containing a uretdione group, an isocyanurate group, a carbodiimide group, a uretonimine group, a urea group and a biuret group) generated in the process of synthesizing isocyanate. The generation relates to a method of solubilizing a hardly soluble by-product by adding a main amount of oil and an ashless dispersant and distilling the same, which is also different from the present invention. Thus, a method for making it possible to treat the isocyanate process waste liquid alone and effectively using the waste liquid was studied.

  A method for producing a solid fuel in which a mixed liquid obtained by adding an isocyanate process waste liquid to a liquid containing at least one of water and a polyol is agitated and solidified in the presence of oil. The above-described problem is solved by a method for producing a solid fuel characterized by the following. Isocyanate reacts with water or the hydroxyl group of polyol as described above and solidifies while generating heat. When an appropriate amount of oil is added to this system, the solidification reaction becomes slow and the solid reaction rate can be optimized. it can. Here, the isocyanate is insoluble in water and forms droplets (micelles) made of isocyanate in water or polyol. If stirring is performed with a stirrer or the like, the droplets of isocyanate are uniformly dispersed in water or polyol. The isocyanate droplets react with the surrounding water or polyol and finally form stable solid particles having a grain size of rice grains through gel-like particles. Since these solid particles are formed in the presence of oil, they contain about 2 to 5% oil and can be used as a solid fuel having a calorific value of 6,000 to 9,000 cal / g.

  The oil used in the present invention may be anything as long as it is non-reactive with isocyanate and has a flash point of about 40 to 150 ° C. For example, waste oil, kerosene, light oil, heavy oil, etc. have an appropriate flash point. It is preferable. These may be used singly or in combination of two or more. On the other hand, since flammable compounds such as BTX (benzene, toluene, xylene) have a low flash point, they may ignite due to heat generated by the solidification reaction of the isocyanate process waste liquid. Further, there is a possibility that the produced solid fuel may ignite when transported and stored, which is not preferable as the oil used in the present invention. Therefore, it is desirable that the flash point of the oil used in the present invention is around 40 to 150 ° C. as described above.

  The amount of oil added may be 2 to 10 times, more preferably 4 to 6 times the weight of the waste isocyanate waste liquor. Further, the amount of the liquid composed of at least one of water and polyol may be 5 to 8 times, more preferably 6 to 7 times in molar ratio with respect to the isocyanate process waste liquid. Here, water or polyol does not necessarily need to be water or polyol with high purity, and use of waste water or waste polyol is advantageous in terms of cost. Moreover, if the mixing ratio of the isocyanate process waste liquid, water or waste polyol and oil is within this range, a stable solid fuel having a rice grain size and an oil content of 2 to 5% can be produced. When the amount of oil added exceeds the above range, the concentration of water or polyol as the reaction substrate decreases, so the solidification rate of the isocyanate process waste liquid becomes slow, impractical, and conversely below the above range. If the amount of oil added is extremely small or not added at all, the speed of the solidification reaction will increase, the particle size of the solid fuel produced will not be stable, and the most troublesome is the side wall of the reaction can Or sticking to a stirring blade, making it difficult to extract from the reaction can. In addition, the oil content is insufficient and the quality of the solid fuel is deteriorated. Furthermore, the reaction proceeds rapidly to produce a block-like solid, which may cause thermal runaway. Even if the thermal runaway does not occur, the volume of the solid matter inevitably increases, so that the oil does not penetrate into the inside and cannot be used as a solid fuel. In addition, when the amount of water or polyol exceeds the above range, the solidification speed becomes high, and it becomes difficult to control the quality of the solid fuel, and when it falls below, the solidification speed becomes slow. When the treatment efficiency is reduced or the amount of water or polyol is excessively small, the reaction substrate is insufficient and unreacted isocyanate process waste liquid remains in the reaction can.

  Further, it is preferable to add flammable sawdust, dripping coffee residue, okara, and the like to react, since solid fuel particles grow using these as nuclei (see Example 5 described later).

  If the solidification becomes excessively high, there is a risk of ignition in the reaction can, and if the temperature is excessively low, the efficiency of solidification decreases. Therefore, the solidification is preferably performed at a temperature of 40 to 95 ° C., more preferably 60 It is the range of -90 degreeC. When the reaction is carried out beyond this range, it is desirable to keep the heating upper limit because the equipment becomes large and complicated, for example, a condenser is required for cooling the evaporated oil. On the other hand, when the temperature is lower than the above range, the reaction rate decreases and the processing efficiency deteriorates, which is not preferable. When processing at the mixing ratio and reaction temperature of water or polyol, oil and isocyanate process waste liquid as described above, solidification is carried out for 30 to 150 minutes, more preferably 60 to 75 minutes. Can be processed.

  Stirring may be carried out using a generally used unidirectional stirrer, but the solidification reaction can be carried out more efficiently by using a reciprocating half-rotating stirrer. If the isocyanate process waste liquid is added in several portions to water, polyol, and oil in the order of addition to water, rapid heat generation and non-uniform particle size of the solid fuel are less likely to occur. When all of the isocyanate process waste liquid is solidified, it is separated into an oil layer, an aqueous layer, and a solid fuel by a centrifugal separator or the like. The separated oil layer and water layer can be allowed to stand for a certain period of time, then re-separated into oil and water, and each can be weighed and reused for the next treatment.

The isocyanate process waste liquid of the present invention may be any of aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate. Specifically, hexamethylene diisocyanate, 4,4′-methylenebiscyclohexyl diisocyanate, methylcyclosan 2, 4 (2,6) diisocyanate, 1,3- (isocyanatomethyl) cyclohexane, benzdiisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenyl diisocyanate, lysine diisocyanate, 1,5- Naphthalene diisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, tetramethylene diisocyanate, octamethyle Diisocyanate, decamethylene diisocyanate, dodecadecamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl diisocyanate, 4,4'-dicyclohexylmethane dicyanate, isopropylidene (4-dicyclohexyl isocyanate), phenylene diisocyanate, tolylene diene Examples include isocyanate, diphenylmethane diisocyanate, diphenylmethane diisocyanate, bistolylene diisocyanate, and dimer acid diisocyanate.

  As the waste polyol of the present invention, aliphatic polyol, alicyclic polyol, aromatic polyol, polyhydroxyalkylene glycol, polyhydroxyalkane polyol, arylene bis (polyhydroxyalkylene) polyol, polyester-based polyol, urethane polyol, polyurea polyol, Examples thereof include polyester-based polyurethane polyols. Specifically, ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, octylene glycol, neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol, diethylene glycol, triethylene glycol, dipropylene glycol, dibutylene glycol, di- Glycerin, ditrimethylolpropane, dipentaerythritol, polyhydroxydiethylene glycol, polyhydroxyethylene-polyhydroxypropylene glycol, polyhydroxypropylene glycol, polytetramethylene ether glycol, polyhydroxydibutyl glycol, cyclohexylene glycol, 2,2-bis (4 -Hydroxycyclohexyl) propane, bis (4-hydroxycycline) Hexyl) methane, 2,2-bis (hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) ethane, bis (4-hydroxyphenyl) methane, bis (acryloylhydroxyethyl) hydroxyethyl isocyanate, bis (methacryl) Ylhydroxyethyl) hydroxyethyl isocyanate, polyglycidyl etherno (meth) acrylates of the above-mentioned various polyhydric alcohols, polyester polyols formed from the above polyhydric alcohols and polycarboxylic acids, the above polyhydric alcohols and isocyanates Examples include polyurethane polyols formed from components.

  Conventionally, a solid fuel can be produced from an isocyanate process waste liquid that has been mainly incinerated or landfilled. Thereby, a part of energy and cost required for processing of the isocyanate process waste liquid can be recovered.

  When oil is added, the solid matter generated does not stick to the side wall of the reaction vessel or the stirring blade, and the maintenance of the reaction vessel can be easily performed, and the treatment efficiency of the isocyanate process waste liquid is increased. Further, by adding oil, the particle size and oil content of the solid fuel can be optimally adjusted. In addition, it becomes easy to control the heat of reaction caused by urea or urethanization.

  Hereinafter, embodiments of the present invention will be described with reference to the flowchart of the solid fuel production method of the present invention shown in FIG.

  In a reciprocating half-rotating stirrer, 5 to 8 times the amount of water or polyol 2 is put in a molar ratio with respect to the isocyanate process waste liquid, and 2 to 10 times the amount of oil 1 is added thereto in a weight ratio, followed by stirring 5 While being heated to 45-95 ° C. with a mantle heater provided in a reciprocating half-rotating stirrer. 13.5-15 kg of isocyanate process waste liquid 3 is added here and solidification reaction is started. The reaction is carried out for 30 to 150 minutes while adjusting the temperature of the reaction solution with a temperature controller so that the temperature is maintained at 45 to 95 ° C. In the solidification reaction, carbon dioxide is generated and fine bubbles are formed in the reaction solution. The reaction is stopped when the bubbles disappear and the carbon dioxide concentration in the reaction solution becomes zero. After cooling the reaction solution to room temperature, the slurry floating on the reaction solution surface layer is centrifuged to precipitate. The solid fuel 4 can be obtained by removing water or a mixed liquid of polyol and oil by vacuum and separating from the cake (solid particles) precipitated (solid-liquid separation 6).

Hereinafter, it demonstrates more concretely, showing the conditions of experiment. The oil content, heat quantity, and particle size shown in Examples 1 to 5 and Comparative Examples 1 to 3 were calculated or measured by the following methods.
1. Sampling and drying A portion of cake (solid particles) in a bag in a centrifuge, 50 g, is placed in a porcelain evaporating dish, and the attached oil is dried and removed while stirring on a plate heater at 120 ° C./30 minutes.
2. Measurement of heat quantity and particle size The dried cake was measured for heat quantity and particle size.
3. Calculation of oil content The oil content was calculated from the following equation.
Oil content (%) = 1− (cake weight after drying / cake weight before drying) × 100

[Example 1]
10 kg of water was put in a reaction can equipped with a reciprocating half-rotating stirrer, 80 kg of light oil was added thereto, and the mixture was heated to 80 ° C. by external steam heating while stirring. 15 kg of isocyanate process waste liquid containing 92% TDI was added thereto to initiate a solidification reaction. The reaction was carried out while adjusting the temperature so that the temperature of the reaction solution was maintained at 80 to 83 ° C. At this time, until about 30 minutes from the start of the reaction, the water, light oil and TDI source were each non-uniform, but the TDI source was a transparent low viscosity liquid. As the reaction progressed, it eventually became cloudy and a gel-like substance was formed, and as the reaction proceeded further, the gel-like substance became solid particles and floated as a slurry in the liquid. The reaction was stopped when the generation of bubbles disappeared and the carbon dioxide concentration in the gas phase of the reactor became zero (95 minutes after the start of the reaction). After cooling the reaction solution to room temperature, the slurry floating on the reaction solution surface layer is separated using a centrifuge, the mixture of water and oil is removed, and the cake (solid particles) in the bag in the centrifuge And 13.7 kg of solid fuel was obtained. Table 1 shows the experimental conditions, and Table 2 shows the calorific value, average particle size, and oil content of the obtained solid fuel.

[Example 2]
Instead of light oil, 100 kg of kerosene and 13.5 kg of an isocyanate process waste liquid containing 87% isocyanate MR were added, and the reaction temperature was 80 to 85 ° C., and the same treatment as in Example 1 was performed. Until about 40 minutes after the start of the reaction, the MR source was a transparent, low-viscosity liquid. Thereafter, it took 115 minutes after the start of the reaction until the carbon dioxide concentration in the gas phase of the reactor became zero and the reaction was stopped. After the reaction was stopped, solid-liquid separation was performed in the same manner as in Example 1 to obtain 11.1 kg of solid fuel. Table 1 shows the experimental conditions, and Table 2 shows the amount of heat, particle size, and oil content of the obtained solid fuel.

[Example 3]
Instead of light oil, 80 kg of A heavy oil and 13.5 kg of isocyanate process waste liquid containing 91% isocyanate HDI were added, and the reaction temperature was changed to 80 to 85 ° C., and the same treatment as in Example 1 was performed. Until about 40 minutes after the start of the reaction, the HDI source was a transparent, low-viscosity liquid. Thereafter, it took 136 minutes from the start of the reaction until the carbon dioxide concentration in the gas phase of the reactor became zero and the reaction was stopped. After the reaction was stopped, solid-liquid separation was performed in the same manner as in Example 1 to obtain 10.8 kg of solid fuel. Table 1 shows the experimental conditions, and Table 2 shows the calorific value, average particle size, and oil content of the obtained solid fuel.

[Example 4]
In place of diesel oil, 80 kg of A heavy oil and 14.8 kg of isocyanate process waste liquid containing 87% isocyanate MDI were added, and instead of water, a solution in which 5.5 kg of polyester waste liquid was added as a polyol solution was used. The treatment was performed in the same manner as in Example 1 except that the temperature was 85 ° C. Until about 40 minutes after the start of the reaction, it was a low-viscosity liquid with a clear feeling. Thereafter, it took 84 minutes after the start of the reaction until the carbon dioxide concentration in the gas phase of the reactor became zero and the reaction was stopped. After stopping the reaction, solid-liquid separation was performed in the same manner as in Example 1 to obtain 12.6 kg of solid fuel. Table 1 shows the experimental conditions, and Table 2 shows the calorific value, average particle size, and oil content of the obtained solid fuel. The polyester waste liquid here is an in-process waste liquid in which a reaction molar ratio is reacted erroneously when synthesizing polyethylene terephthalate by condensation polymerization of ethylene glycol and terephthalic acid, and contains about 63% ethylene glycol. Was used.

[Example 5]
In the same manner as in Example 1, 8.0 kg of water, 0.3 kg of sawdust, and 80 kg of kerosene were added to a reaction can equipped with a reciprocating half-rotating stirrer and heated to 80 ° C. while stirring. This was treated in the same manner as in Example 1 except that 20 kg of the isocyanate process waste liquid containing 79% MDI was added to start the solidification reaction. Until about 50 minutes after the start of the reaction, the MDI source was a transparent, low-viscosity liquid. Thereafter, it took 120 minutes after the start of the reaction until the carbon dioxide concentration in the gas phase of the reactor became zero and the reaction was stopped. After stopping the reaction, solid-liquid separation was performed in the same manner as in Example 1 to obtain 11.8 kg of solid fuel. Table 1 shows the experimental conditions, and Table 2 shows the calorific value, average particle size, and oil content of the obtained solid fuel.

[Comparative Example 1]
In the same manner as in Example 1, 10 kg of water was placed in a reaction can equipped with a reciprocating semi-rotating stirrer and heated to 80 ° C. by external steam heating while stirring. Without adding oil such as light oil, 15 kg of only the isocyanate process waste liquid containing 92% TDI was charged to initiate the solidification reaction. The temperature of the reaction solution was adjusted so as to be maintained at 80 to 83 ° C. At this time, until about 40 minutes after the start of the reaction, the water and the TDI source were non-uniform, but the TDI source was a transparent, low-viscosity liquid until about 40 minutes. As the reaction proceeds, it eventually becomes cloudy and a gel-like substance is formed. Furthermore, the gel-like substance is slurried in the liquid and does not float with a certain particle size, and a large amount of the substance reacts. It stuck to the side wall and stirring blade of the can in a solid state, and it was not easy to take out from the reaction can. Therefore, only 2.1 kg of solid fuel was obtained. Table 1 shows the experimental conditions, and Table 3 shows the amount of heat, average particle diameter, and oil content of the obtained solid fuel.

[Comparative Example 2]
The reaction was conducted in the same manner as in Example 4 except that the isocyanate process waste liquid containing 88% isocyanate HDI was replaced without adding oil such as A heavy oil. As a result, in this case as well, it adhered to the side wall of the reaction vessel and the stirring blade, and was not easily taken out from the reaction vessel. Therefore, only 2.4 kg of solid fuel was obtained. Table 1 shows the experimental conditions, and Table 3 shows the amount of heat, average particle diameter, and oil content of the obtained solid fuel.

[Comparative Example 3]
In the same manner as in Example 5, 8.0 kg of water and 0.3 kg of sawdust were placed in a reaction can and heated to 80 ° C. by external steam heating while stirring. Without adding oil such as kerosene, 20 kg of only the isocyanate process waste liquid containing 79% MDI was charged to start the solidification reaction. The temperature of the reaction solution was adjusted so as to be maintained at 80 to 83 ° C. At this time, until about 30 minutes from the start of the reaction, the water and TDI sources were each non-uniform, but the MDI source was a transparent, low-viscosity liquid. As the reaction proceeds, it eventually becomes cloudy and a gel-like substance is formed. Furthermore, the gel-like substance is slurried in the liquid and does not float with a certain particle size, and a large amount of the substance reacts. It stuck to the side wall and stirring blade of the can in a solid state, and it was not easy to take out from the reaction can. Therefore, only 2.8 kg of solid fuel was obtained. Table 1 shows the experimental conditions, and Table 3 shows the amount of heat, average particle diameter, and oil content of the obtained solid fuel.

  As is apparent from the results of Tables 2 and 3, according to the present invention, a fuel having a uniform particle size and excellent handling can be provided. It is said that the calorific value of good quality coal is about 6,700 cal per gram, indicating that the fuel of the present invention has a calorific value equal to or higher than that of coal.

  Further, according to the present invention, it is possible to efficiently convert an isocyanate process waste liquid, which has conventionally been difficult to dispose of, into a fuel without sticking to a reaction tube.

It is the flowchart which showed the flow of the solid fuel manufacturing method of this invention.

Explanation of symbols

1 Oil 2 Water or polyol 3 Isocyanate process waste liquid 4 Solid fuel 5 Stirring 6 Solid-liquid separation

Claims (5)

A method for producing a solid fuel in which a mixed liquid obtained by adding an isocyanate process waste liquid to a liquid containing at least one of water and a polyol is agitated and solidified in the presence of oil. A method for producing a solid fuel characterized by the above. The method for producing a solid fuel according to claim 1, wherein an oil containing at least one of waste oil, kerosene, light oil or heavy oil is used as the oil. The method for producing a solid fuel according to claim 1, wherein the amount of oil added is 2 to 10 times the weight ratio of the waste isocyanate waste liquid. 2. The method for producing a solid fuel according to claim 1, wherein the amount of the liquid composed of at least one of water and polyol is 5 to 8 times the molar ratio of the waste isocyanate waste liquid. 2. The method for producing a solid fuel according to claim 1, wherein the solidification is performed at 40 to 95 ° C. with stirring for 30 to 150 minutes.

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