JPS58222191A - Production of solid fuel/water slurry - Google Patents

Abstract

PURPOSE:To obtain low-viscosity and high-concn. slurry by blending two kinds of pulverized solid fuels different in ash content and geometrical average diameter so as to give a particle size distribution in a specified range and producing a slurry using the obtd. solid fuel. CONSTITUTION:A pulverized solid fuel of low ash content (A) such as petroleum coke or deashed coal of <=about 6wt% ash content and <about 44mu geometrical average diameter is mixed with a pulverized solid fuel (B) of a geometrical average diameter larger than that of the component A and an ash content greater than that of the component A in a wt. ratio of A/B of about 0.5- 2, to produce a fine solid fuel having <=150mu geometrical average diameter and a particle size distribution in a range of 3.5-12 in terms of geometrical standard deviation in logarithmic normal distribution. Then the purpose solid fuel/water slurry is obtd. by mixing the obtd. fine solid fuel with water, or water and a dispersant.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a solid fuel-water slurry with low viscosity and high concentration.

More specifically, the present invention relates to an improvement in a method for producing a solid fuel-water slurry by mixing one solid fuel such as one coal and one petroleum coke with water or water and a dispersant, and is related to improvements in the method for producing a solid fuel-water slurry, such as transportation, storage, handling, etc. The present invention relates to a method for producing a low-viscosity, high-concentration solid fuel-water slurry that is easy to produce.

In recent years, solid fuels such as coal and petroleum coke have been reconsidered as energy sources. However, coal, petroleum coke, etc. are easier to transport and store than fluid fuels such as petroleum.

Moreover, not only are the costs required for these products high, but they also have the disadvantage of being inefficient and difficult to use compared to oil.

Therefore, in order to improve these shortcomings, solid fuel is made into fine powder2, for example, coal is made into fine powder and dispersed in water.
Progress is being made in developing methods to form solid fuel-water slurries, such as coal-water slurries.

However, when converting coal into a coal-water slurry, increasing the concentration of coal generally increases the viscosity of the slurry significantly, causing loss of fluidity and making handling and pipe transportation difficult. On the other hand, if the concentration of coal is lowered to lower the viscosity of the slurry, the transport efficiency will decrease, and a dehydration process will be required as a ridge treatment in order to use it as a fuel or gasification raw material.

In order to solve these problems, it is necessary to produce a solid fuel-water slurry with low viscosity and high concentration, such as a coal-water slurry. A method of reducing slurry viscosity by mixing solid fuel with water and a dispersant, ■Using a finely powdered solid fuel with an adjusted particle size distribution as a finely powdered solid fuel and mixing it with water or water and a dispersant. Methods of increasing the solid fuel concentration in slurry are known. ■and■
Although these methods are effective in reducing the viscosity and increasing the concentration of slurry, none of the methods can be said to be sufficient and there is room for improvement.

The present inventors further conducted extensive research with the aim of developing a method for industrially advantageously producing a solid fuel-water slurry with a low viscosity and high concentration.

As a result, instead of simply using a dispersant or using a finely powdered solid fuel that is obtained by pulverizing coal into fine powder and adjusting its particle size distribution.

For example, a coal with a low ash content, such as deashed coal or petroleum coke, and a coal with a high ash content, such as non-deashed coal, are used together, and the particle size of the former is smaller than that of the latter non-deashed coal. It was discovered that the above object could be achieved by using a particle having a wide particle size distribution within a certain range, and after further research, the present invention was arrived at.

The present invention provides a method for producing a solid fuel-water slurry by mixing solid fuel with water or water and a dispersant. A) and a pulverized solid fuel (B) having a larger geometric mean diameter than (A) and a higher ash content than (A) are mixed, and the geometric mean diameter is 150μ or less and the particle size distribution is a lognormal distribution. The present invention relates to a method for producing a solid fuel-water slurry characterized by using a finely powdered solid fuel having a geometric standard deviation σ7 in the range of 3.5 to 12.

The terms "geometric mean diameter" and "geometric standard deviation (σr) J" used in this specification are terms commonly used to define the particle size of powder and its distribution, and each The term is defined as follows from the relationship between particle size and integrated passing weight coefficient in lognormal distribution.

Definition of geometric mean diameter: Particle size whose cumulative passing weight percentage is equivalent to 50 inches Definition of geometric standard deviation (σ1): Ratio between the geometric mean diameter and the particle diameter where the cumulative passing weight ratio is equivalent to +5.87% ( Geometric mean diameter/cumulative passing weight 15.87 Particle size (extremely phased) σy+
and the ratio of the particle diameter corresponding to the cumulative passing weight coefficient of 84.13% to the geometric mean diameter (particle diameter corresponding to the cumulative passing weight of 84.13%/geometric mean diameter) According to the present invention, a low viscosity solid fuel-water slurry having a high concentration of solid fuel and practical fluidity can be easily produced. The fuel-water slurry is transported by pipes, etc., and injected by burners, etc.

It is easy to handle and is suitable for use as a fuel in boilers, power plants, heating furnaces, etc., and as a gasification raw material for producing hydrogen, carbon oxide, etc.

Still, in the present invention, the pulverized solid fuel used can not only be prepared by industrially simple operations;
Since it is not necessary to use a pulverized solid fuel that has a low ash content and has been completely deashed, the cost required for deashing can be significantly reduced. Furthermore, in the present invention, a solid fuel-water slurry with low viscosity and high concentration can be obtained, so that it can be used for various purposes without any special dehydration treatment at the time of use.

In the present invention, it is important to use a pulverized solid fuel (A) having a geometric mean diameter of about 44μ, preferably smaller than 20μ, and a low ash content as a part of the pulverized solid fuel. Fine powder solid fuel with a small average diameter but high ash content.

For example, if undeashed coal is used, it will be difficult to achieve the two objectives of the present invention because it will prevent the solid fuel-water slurry from becoming low in viscosity and high in concentration. The reason why low viscosity and high concentration are inhibited when undeashed coal is used is not fully clear, but when the geometric mean diameter becomes smaller than about 44μ, the surface area increases significantly as the geometric mean diameter decreases, especially when undeashed coal is used. It is thought that this is because the ash content in the deashed coal becomes more likely to be liberated into the water, increasing the ash content leached into the water.

In the present invention, the pulverized solid fuel (A) is generally petroleum coke produced as a by-product from petroleum refining processes (usually having an ash content of about 0.1 to 1% by weight or ash content deashed by a known method). Content about 6% by weight or less, preferably 4.5%
Examples include items below the weight category. Particle size adjustment of the still fine powder solid fuel (A) may be carried out wet or dry, and can be easily carried out using a conventionally known pulverizer 9 such as a ball mill, tube mill, percussion mill, etc. . In addition, if the value of the geometric mean diameter of the pulverized solid fuel (A) is too large, the particle size distribution when mixed with the pulverized solid fuel (B) becomes narrow, which is a factor that inhibits increasing the concentration of the solid fuel-water slurry. Therefore, the geometric mean diameter is approximately 44μ or less,
Preferably, the thickness is 20μ or less.

In the present invention, the pulverized solid fuel (B) is one that has a larger geometric mean diameter than the pulverized solid fuel (A) and has a higher ash content than (A) 1 For example, non-deashed coal (normally ash content (approximately 10% by weight) is used.

Therefore, there is an advantage that the cost required for deashing treatment is reduced. In addition, the geometric mean diameter of the pulverized solid fuel (B) is larger than that of the pulverized solid fuel f'l (A), so in other words, the pulverized solid fuel (B) can be relatively coarse particles, so the cost required for pulverization is In addition, since the particles are relatively coarse, it is possible to prevent ash from leaching into water when the solid fuel is made into a water slurry. This has the effect that the influence of ash content can be reduced without depending on the condition. If the geometric mean diameter of the pulverized solid fuel (B) is smaller than about 44p, it is not suitable because the ash content tends to be liberated in the water and the amount of eluted ash increases. There is no particular upper limit to the geometric mean diameter of the pulverized solid fuel (B).

If this becomes too large, the reactivity and combustibility during use of the solid fuel-water slurry will deteriorate, so taking these into consideration, it is appropriate that the upper limit is 150μ or less. Particle size adjustment of the fine powder solid fuel (B) may be carried out wet or dry, and can be easily carried out using a conventionally known pulverizer 9 such as an attrition mill, hammer mill, rod mill, etc. .

In the present invention, the above (A) and (B) are used as the fine powder solid fuel, and the mixing ratio of (A) and (B) is (A) / (B) -0.05 to 2 by weight. ．． Preferably 0.1 to 1 is desirable. If the ratio of (A) is too small, the effect of the present invention will not be sufficiently expressed, and if it is too large, not only will the cost required for pulverization increase, but also the cost of deashing the coal etc. Therefore, it is desirable that the mixing ratio be within the range specified in 2.

In the present invention, a mixture of pulverized solid fuel (A) and pulverized solid fuel (B) is used as the pulverized solid fuel, and this pulverized solid fuel has a geometric mean diameter of 15
0μ or less, preferably 74μ or less.

The particle size distribution is a lognormal distribution with a geometric standard deviation σ of 3
．． 5-12. Preferably, it needs to be in the range of 6 to 12. The present inventors have discovered that the larger the value of σg of the pulverized solid fuel (the wider the particle size distribution), the lower the viscosity of the solid fuel-water slurry can be made.

In the present invention, in order to make the value of σ of the pulverized solid fuel more than 12, it is necessary to use a pulverized solid fuel (B) with a geometric mean diameter as large as possible, or to use a pulverized solid fuel (A) with a geometric mean diameter as large as possible. However, if the geometric mean diameter of (B) is too large, the reactivity of the solid fuel-water slurry will decrease.
In addition, in order to reduce the geometric mean diameter of (A), it is necessary to prepare extremely finely pulverized (A), and there is an industrial limit to the degree of pulverization, making it uneconomical. not.

Also, if the value of σ7 is smaller than 6.5, the particle size distribution becomes 1]
becomes too narrow, and when trying to increase the concentration of the solid fuel-water slurry, the viscosity of the slurry becomes significantly high. Therefore, taking these into account, the σ and geometric mean diameter of the pulverized solid fuel mixed with (A) and (B) need to be within the above ranges.

The present invention can be easily carried out by mixing pulverized solid fuel with water or water and a dispersant. When mixed with water and dispersants.

A stable solid fuel-water slurry with lower viscosity and higher concentration than when mixed with water alone can be obtained. As the dispersant, any conventionally known dispersant for solid fuel-water slurry can be used. Examples of dispersants include naphthalene sulfonate 15 oil sulfonate,
Lignin sulfonates and their formalin condensates: polyoxyethylene alkyl ether sulfate salts, polyoxyethylene alkylaryl ether sulfate salts; polyglycerin sulfates; melamine resin sulfonates; coal extract sulfonic acids Salt (Special request 1982)
-192965).

The amount of dispersant used is 0.01 per solid fuel-water slurry.
It is appropriate to adjust the amount to 3% by weight. Further, in addition to the dispersant, an alkali metal base 9 such as sodium hydroxide may be mixed, and the amount used is preferably 2 weight percent or less relative to the solid fuel-water slurry.

In the present invention, there is no particular restriction on the mixing order in mixing the pulverized solid fuel with water or water and a dispersant. For example, pulverized solid fuel II (A) and pulverized solid fuel (
B) may be mixed in advance and then mixed with water or water and a dispersant, or (A) may be mixed first with water or water and a dispersant and then (B) may be mixed; ) may be first mixed with water or water and a dispersant, and then (A) may be mixed.

Next, examples and comparative examples will be shown.

For each side, the fine powder solid fuel is obtained by dry or wet ball milling of the industrial analysis values (constant humidity basis, J-engineering 5-M-8s 12) listed in Table 1, and the results are listed in Table 2. The geometric mean diameter and geometric standard deviation were used.

Table 1 In Table 1, E-1 is Wallara coal, E-2 is Wallara coal deashed by heavy liquid coal washing, F-1 is Northern Valley coal, and F-2 is Hunter Valley coal. G indicates coal valley coal and H indicates petroleum coke that has been decalcified by heavy liquid coal washing (the same applies hereinafter).

Hehehehe Table 2 Also, on each side, the production of solid fuel-water slurry and the measurement of viscosity were carried out in the following manner.

To water to which a dispersant (a surfactant whose main component is β-naphthalene sulfonic acid formalin condensate) was added in advance,
Mix the fine powdered solid fuel listed in Table 2 and add it alone, mix for about 5 minutes with a paddle stirrer to produce a solid fuel-water slurry, immediately transfer it to a viscosity measuring container, and measure it with a B-type viscometer. (manufactured by Tokyo Keiki) to measure slurry viscosity. The dispersant was added to the slurry in an amount of 0.5% by weight.

Still on each side, the solid fuel concentration of the solid fuel-water slurry is expressed as the solid fuel weight (bone dry basis) divided by the total weight of the slurry.

Examples 1 to 3 and Comparative Examples 1 to 2 The pulverized solid fuels listed in Table 2 were mixed at the mixing ratios listed in Table 6 to adjust the geometric mean diameter and geometric standard deviation of the pulverized solid fuels. Solid fuel-water slurries were produced in which the solid fuel concentrations were changed to those listed in Table 6, and the respective slurry concentrations were measured. The results are shown in Table 6.

Table 3 shows that when a fine powder solid fuel with a high ash content is used alone, or when a fuel with a low ash content but a narrow particle size distribution is used (Comparative Example 1, Comparative Example 2) The solid fuel of the present invention has a much lower viscosity and higher concentration than the case where the width of the particle size distribution is wide but the geometric mean diameter is small and the ash content is high (comparative example). It turns out that water slurry can be produced.

Table 6 Example 4 and Comparative Example 4 As a fine powder solid fuel, the mixing ratio of A-5 and B-3 was changed as shown in Table 4 (Example 4).

Also, by changing the mixing ratio of A-4 and B-3 (Comparative Example 4),
Solid fuel-water slurries each having a slurry viscosity of 3000 cp were produced.

Table 4 shows the solid fuel concentration in the slurry when the slurry viscosity is 3000 cp.

Table 4 shows that according to the present invention, the larger the geometric standard deviation σ2 of the pulverized solid fuel, the more highly concentrated solid fuel-water slurry can be produced, whereas the one with a high ash content (non-deashed coal) was used as the fine powder solid fuel (Comparative Example 4), it can be seen that it is difficult to produce a slurry with a high solid fuel concentration even if the particle size distribution is adjusted and the σ is made thicker.

Table 4 Patent Applicant Ube Industries Co., Ltd. Procedural Amendment (Method) June 72, 1939 Director General of the Patent Office 1. Indication of Case Patent Application No. 10375-1982 2 Name of Invention Solid Fuel - Water slurry manufacturing method 3, relationship with the case of the person making the amendment Patent applicant postal code 755 1-12-32 Nishihonmachi, Ube City, Yamaguchi Prefecture Telephone: 03 (5)
81) 3311 4 Date of amendment order September 28, 157 (final date) 5 Column 6 of detailed explanation of the invention in the specification subject to amendment, Contents of amendment (1) Pages 16 and 14 , the full texts of pages 16 and 18 are revised as shown in the attached sheets.

□ that's all \、 Next, examples and comparative examples will be shown.

For each side, the fine powder solid fuel is obtained by dry or wet ball milling of the industrial analysis values (constant humidity basis, J Engineering S-Mf8812) listed in Table 1, and the geometric averages listed in Table 2. The diameter and geometric standard deviation were used.

Table 1 In Table 1, E-1 is Wallara coal, E-2 is Wallara coal deashed by heavy liquid coal washing, F-1 is Hunter Par L/- coal, and F-2 is Hunter Valley coal. G indicates coal valley coal and H indicates petroleum coke that has been decalcified by heavy liquid coal washing (the same applies hereinafter).

Table 2 Also, on each side, the production of solid fuel-water slurry and the measurement of viscosity were carried out in the following manner.

To water to which a dispersant (a surfactant whose main component is β-naphthalene sulfonic acid formalin condensate) was added in advance,
The fine powdered solid fuels listed in Table 2 are added together or singly, mixed with a paddle stirrer for about 5 minutes to produce a solid fuel-water slurry, immediately transferred to a viscosity measuring container, and then transferred to a B-type viscometer ( Slurry viscosity was measured using a (manufactured by Tokyo Keiki). The dispersant is Sura Table 3 (16) ＼ Table 4 (18)

Claims (1)

[Claims] (A method for producing a solid fuel-water slurry by mixing solid fuel with water or water and a dispersant, wherein the solid fuel has a geometric mean diameter of less than about 44 μm and has a low ash content. A mixture of pulverized solid fuel (A) and pulverized solid fuel (B), which has a larger geometric mean diameter than (A) and has a higher ash content than (A), with a geometric mean diameter of 15
A method for producing a solid fuel-water slurry, characterized in that a finely powdered solid fuel is used which is 0 μ or less and has a particle size distribution with a geometric standard deviation σ7 of lognormal distribution in the range of 6.5 to 12. (2) The mixing ratio ((A)/(B), (weight ratio)) of the fine powder solid fuel (A) and the fine powder solid fuel (B) is 0.
Solid fuel according to claim 1 which is 05-2.
Method for making water slurry. (3) The method for producing a solid fuel-water slurry according to claim 1, wherein the pulverized solid fuel (A) is petroleum coke or deashed coal having an ash content of about 6% by weight or less. (4) The method for producing a solid fuel-water slurry according to claim 1, wherein the pulverized solid fuel (B) is non-deashed coal.