JPS5889693A - Fuel composition and its preparation - Google Patents

Abstract

PURPOSE:To obtain a fuel composition which can be gasified or burnt in a solid state in a remarkably short time, and has excellent physical stability, by impregnating methanol fuel into coal particles, and dispersing the particles in mineral oil. CONSTITUTION:The objective liquid-solid suspension fuel composition is prepared by impregnating (A) about 3-30(wt)% methanol fuel into (B) about 25- 55% coal particles, and dispersing the impregnated particles in (C) about 20- 70% mineral oil. The component (B) is e.g. anthracite, semi-bituminous coal, bituminous coal, brown coal, etc., and the crushing of the coal can be carried out either by dry process or by wet process.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for preparing coal particles impregnated with methyl fuel in mineral oil.
The present invention relates to a stable fuel composition obtained by making it cloudy and a method for producing the same.

In recent years, coal has been attracting attention as an alternative to petroleum-based fuels, and there are many plans to replace conventional mineral oil combustion with coal combustion.

However, the trap of converting to coal combustion is often largely due to technical constraints in the preparation, storage, transportation, and consumption of coal, which is a solid fuel. Therefore, fluidized fuel (hereinafter abbreviated as COM), which is a mixture of mineral oil and coal particles, has been developed as a more efficient fuel that can reduce the amount of mineral oil used and can be handled in the same way as mineral oil. [30-50
Although it is a liquid-isomer suspension containing a mixture of coal particles with a high temperature, the major problem when using it as a fuel is the fuel composition, which is mainly due to the extremely slow combustion rate of coal particles compared to mineral oil. This is due to its poor flammability. For this reason, when a heavy oil-fired power plant is converted to Ilar YCOM combustion, the amount of heat that can be generated normally decreases by several 1O compared to mineral oil, and the power generation capacity decreases as well.

In this specification, methyl fuel may be composed of methanol alone, or may be composed mostly of methanol in a mixture with an oxygen-containing compound such as a lower alcohol having 2 to 4 carbon atoms; Mineral oil refers to mineral-based oil with a certain degree of viscosity, which can contain up to 50% water, and includes petroleum and petroleum products, extracted oil from oil shale or oil sands, and synthetic oil from coal. This includes: In addition, the coal particles are obtained by crushing at least one grain of coal selected from the group of anthracite, bituminous coal, subbituminous coal, and lignite, and the particle size is approximately 60 to 74JI or less.
90 vNI and friends.

In this way, the combustion of COM is the best as in the previous case (two-stage combustion of residual solid combustion is not performed). Although there is a change in the volume-based specific surface area diameter of the grains, no splitting is observed.

The behavior during the subsequent solid combustion period is almost the same as #1 single combustion of coal, and the combustion speed is extremely low (Journal of Japan Fuel Association Vol. 59, No. 642, pp. 822-831, Vol. 60, No. 6 of the same journal)
47, pp. 183-191) On the other hand, the combustion of friendly coal particles impregnated with methyl fuel is
Similar to COM, there is two-stage combustion, but the behavior of each combustion is different from COM. In COM, mineral oil does not penetrate into the two-crop pores of coal particles and instead wets or envelops the surface of the coal particles, whereas in the case of -6 coal particles impregnated with methyl fuel, methyl fuel is used in comparison with heavy oil. Due to its low molecular weight, surface tension, and viscosity, and high compatibility with water, it penetrates into the microfa of coal particles and replaces urine in the microfa. Therefore, during the combustion of coal particles impregnated with methyl fuel, the methyl fuel that has entered the tioxtt a of the coal particles is rapidly vaporized and expanded from near the surface of the coal during the first stage of gasification combustion, and the solid particles Since the material is explosively combusted while being crushed and scattered, the volume-based specific surface area diameter decreases at a large rate, and the gasification and sintering time is shortened, as well as the solid combustion time.

By impregnating methyl fuel and creating a liquid-solid suspension in which coal particles are encapsulated in mineral oil, the present invention does not lose the advantage of high calorific value of COM, but reduces the combustibility which is a major disadvantage. According to tests, the combustion behavior of the fuel composition of the present invention (hereinafter referred to as Metacom), which is intended to improve the negative effects, achieved the expected effect, and the overall combustion time was equal to that of COM under the same conditions. In comparison, the MIi of coal and mineral oil
Although it varies depending on the mixing ratio of coal and mineral oil, it is approximately 2
/3 to 1/2 shortened schedule.

On the other hand, by impregnating methyl fuel into coal particles, Metacom becomes a fuel composition in which coal particles are substantially uniformly dispersed in mineral oil, that is, excellent in physical stability.

The stability mechanism of COM is generally thought to be as follows.The coal particle surface is usually in a mixed state of inorganic substances, hydrocarbons, etc.9, and water preferentially attaches to the highly polar parts of the inorganic substances. However, when these coal particles are mixed with mineral oil, a large interfacial tension is created at the interface, which increases the energy level of the system, causing them to bond with each other and coagulate. The aggregated and enlarged coal particles settle at a speed proportional to the square of the diameter, condense, and form a so-called consolidated layer at the bottom of the storage container. It is difficult to eliminate this problem and return the whole to the original homogeneous suspension, so in order to reduce the interfacial force and create a state where the water is mixed with the coal, the coal particles form a weak bond through the water. It exhibits no agglomeration and maintains a stable state of Nt/.

And\, methyl fuel has a higher surface tension than water.

Because the main component is methanol, which has a low viscosity.

When Metacom is made using coal particles impregnated with an appropriate amount of methyl fuel, the interfacial tension is lower than that of COMK without the addition of surfactant V. Therefore, the methyl fuel forms a t-a shape 11 on the coal surface, causing the coal particles to aggregate. It is considered that this method shows excellent stability because it creates a weak bond between coal particles and prevents the particles from settling.

Furthermore, the feature of this fuel composition is that the outer surface of the methyl fuel impregnated in the coal particles is surrounded by mineral oil, so even when heated to 60 to 65 degrees Celsius, which is around the boiling point of methanol. Exists in a stable state without being dispersed.

The mixing ratio of each component of the fuel composition in the present invention can be appropriately selected by the practitioner from the range of 25 to 55 wtl of coal particles, 51 to 51 wtl of methyl fuel, and 20 to 70 wtl of mineral oil. 4h coal particles 25wt4, methyl fuel AVT, mineral oil 20wt when no drops or coal particles 55wt4, methyl fuel 30Vt, mineral oil 70W
If the amount exceeds 10,000 yen, the objective of the present invention cannot be achieved technically and economically.

Next, the manufacturing method of the present invention will be explained based on FIGS. 1 and 2. In the method shown in FIG. 1, coal is pulverized into coal particles of an appropriate particle size in a dry pulverizer 1, and these coal particles are mixed with an appropriate amount of methyl fuel in a mixer 2. The methyl fuel-impregnated coal particles thus obtained are sent to a kneader 4 where they are kneaded with mineral oil to form Metacom. In the method shown in FIG. 2, coal and methyl fuel are placed in a wet pulverizer 1, pulverized into suitable coal particles, and mixed with methyl fuel. As the methyl fuel, new methyl fuel and/or methyl fuel recovered by the dehydrator 3 is used. When the mixture with methyl fuel is in excess,
Surplus methyl fuel is recovered by dehydrator 3. When the mixture is in an appropriate proportion, it is sent as is to the kneading machine 4 and kneaded with mineral oil in C- to form Metacom.

The mixing ratio of coal particles, methyl fuel and mineral oil can be appropriately selected by the practitioner within the range of the ratios described in claim (2)K.

Further, the grinding time, mixing time, deliquification time and kneading time can be appropriately selected by the practitioner in consideration of the type of coal and mineral oil used.

A commercially available crusher can be used. As a mixer, a stirring type and 4-particle suspension type can be conveniently used, but when using a particle suspension type mixer, by adjusting the amount of methyl fuel that is sprayed onto the coal particles, it is possible to mix the desired amount of methyl fuel. It is possible to produce coal particles impregnated with the dewatering machine, and in some cases, the dewatering machine can be connected to an oil line. Commercially available dewatering machines and kneading machines can be used. The following Examples and Comparative Examples clearly demonstrate the present invention.

Example 1 Rice-M charcoal (Am charcoal raising) v After air drying, it was pulverized with a dry pulverizer vibrating mill so that it contained approximately 70 m of 74 s or less at 1000 F.
obtained coal particles. Over the course of 20 minutes, excess methanol that has not been impregnated into the coal particles is removed to obtain methanol-impregnated coal particles 690F, which are then placed in a rotary mixer (middle).
[Metacom was made by adding 500 tl of CX oil and kneading at 60°C for 45 minutes. This Metacom was transferred to a 1000-meter cylinder and left at 60 DEG C. for 14 days.The thickness of the compacted layer was measured and found to be 2. This indicates that the composition is a stable liquid-solid suspension. A 6 mφ, 409 iron rod was used to measure the consolidated layer.

The industrial analysis values of the US M coal used are as follows.

Moisture Ash Volatile matter Fixed carbon Total sulfur Calorific value (
vNl) (vtl) (vtl) (vtl)
(wtl) (Kj/X?) 17.3 6.8
32.6 43.3 0.8 5500 Example 2 Canadian C coal (◆bitten coal) was crushed in the same manner as in Example 1 and 10
Coal particles of 00F were obtained. This coal particle 500fY was treated in the same manner as in Example 1, and methanol-impregnated coal particle 77
Obtained 0fV. Similar to Example 1, 500 tons of Middle East C heavy oil was added and kneaded at 60° C. for 45 minutes to produce Metacom. When the same test as in Example 1 was conducted on the Metacom, the thickness of the consolidated layer was found to be! -It was. This indicates that the composition is a stable liquid-solid suspension.

The industrial analysis values of the Canadian C charcoal used are as follows.

Moisture Ash Volatile matter Fixed carbon Total sulfur Calorific value (
wn) twtl) (vtl) (vtl)
(wt regret) (Kmvkc9)? ,0 10.1
33.8 49.1 0.2 6220 Comparative Example 1 U.S. M Coal 5 containing approximately 704 μm or less of 74μ obtained in Example 1
00t1, put it in a mixer for 1 revolution, and add it to this! [C heavy oil 5
Add 00 f)r, knead at 60℃ for 45 minutes, and COM! Had made. Transfer the COM to a 1000-meter graduated cylinder,
After standing at 60°C for 100 hours, the thickness of the dense layer was measured to be 160cm, which indicates that C without surfactant.
OM is an unstable liquid-solid suspension.

Comparative Example 2 A COM was produced in exactly the same manner as in Comparative Example 1, except that 4ft Canadian C coal was used in Example 2.

The same operation as in Comparative Example 1 was performed on icOMK, and the thickness of the consolidated layer was measured to be 170 . This shows that the COM is an unstable liquid-solid rrss body.

Next, Metacom of Example 1.2 and Comparative Example 1.20COM
We will explain the combustion test results of

Suspension rate-drop combustion tests with forced shield fire were conducted on Metacom and COMK as a comparison. The test was conducted using combustion air
It is heated to 900°C and supplied to the sample at a constant flow rate. Ignition of the sample + S forced ignition was performed, and combustion behavior was measured. Exam 4
A specimen #I with a diameter of about 2 snow was made by hanging the sample from the tip of a platinum wire with a diameter of 1°0.1■.

The test results are expressed as burning rate coefficients and are shown in Table 1.
is defined by equation (1).

DJ-DJ [m ----(1) D,: Volume-based specific surface area diameter of droplets at the initial stage of combustion (■) D,: Volume-based specific surface area diameter of ash after combustion (-) t: Required combustion time ( a) As shown in No. 111, the rice-M coal is 2.26 times that of Metacom's Kw & ICOH, and the Kaname C coal is 1.
58 times, indicating extremely excellent combustibility. If we look at the combustion behavior of Metacom, we can see that during f-suihi combustion, COM burns as a single droplet without splitting the coal particles, whereas Metacom burns while splitting. This is thought to indicate a high burning rate coefficient.

[Brief explanation of drawings]

FIGS. 1 and 2 are flow sheets of an example of the method for producing the fuel composition of the present invention. In the figure, 1.--Crusher 2.-Mixer 3.-Delictor 4-Mixer 5.-Represents fuel composition storage tank No. 11n Stem tm

Claims (5)

[Claims] (1) A liquid-solid S hot body fuel composition in which mineral oil encapsulates coal particles impregnated with methyl fuel. (2) Coal particles 25-55 wt4, methyl fuel 3-~
3 Ovt, mineral oil 20 to 70 wt4 or a fuel composition according to claim 1. (3) The fuel composition according to claim 2, wherein the coal particles are particles of at least one type of coal selected from the group of anthracite coal, bituminous coal, subbituminous coal, and brown coal. (4) A method for producing a fuel composition according to claim 1, which comprises dry-pulverizing coal, adding methyl fuel thereto and mixing to obtain methyl fuel-impregnated coal particles, and adding mineral oil thereto and kneading. . (5) Wet-pulverize coal particles by adding methyl fuel,
The method for producing a fuel composition according to claim 1, which comprises deliquifying excess methyl fuel to produce methyl fuel-impregnated coal particles, adding mineral oil to the coal particles, and kneading the particles.