JPS5849796A - Additive for coal-water slurry - Google Patents

Abstract

PURPOSE:An additive for coal-water slurry capable of dispersing coal powder into water in high concentration in low viscosity stably for a long time, comprising a solute in a waste liquor discharged in the alcohol fermentation process of waste molasses as an active ingredient. CONSTITUTION:The desired additive comprising a solute (unfermented remaining saccharides, by-product such as glycerol succinate, etc., denatured substance of amino acids, etc., unfermented components such as denatured saccharides, inorganic substances, etc. and chemical additive such as ammonium sulfate, etc.) in a fermented waste liquor discharged in the alcohol fermentation process of waste molasses as an active ingredient. Usually 0.1-5wt% (preferably 0.5- 3.0wt%) additive is added to coal-water slurry.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an additive for coal-water slurry for stably dispersing coal powder in water at a high concentration.

Due to its solid form, coal had long been supplanted as a fuel by petroleum, but in the wake of the oil crisis, coal was reconsidered, and as exemplified by coal-oil mixed fuel (COM), Many attempts have been made to treat coal as a fluid by turning it into powder and mixing it with a medium.

However, in the case of coal-oil mixed fuel, it is impossible to avoid the disadvantage that about half of the fuel is oil, and there is a desire to develop another slurry fuel.

In recent years, efforts have been made to use slurry, a fluid containing highly concentrated coal dispersed in water as a medium, suitable for transportation by pipeline or oil tanker, and also as an alternative fuel to oil in various boilers. Attempts are being made to do so. In the case of this slurry, since the medium is water, it is preferable that the slurry has the following properties.

That is, it must have a high coal concentration and a low viscosity, and it must also have excellent long-term stability without causing coal powder agglomeration or sedimentation.

As a result of intensive studies to obtain a coal-water slurry that satisfies the above-mentioned required characteristics, the inventors added fermentation waste liquid discharged from the alcohol fermentation process of blackstrap molasses as an additive to the coal-water slurry. In other words, by adding a solute contained in this waste liquid as an active ingredient, it is possible to obtain a coal-water slurry with high concentration, low viscosity, and excellent long-term stability. I learned this and came up with this invention.

By the way, in order to improve the characteristics of coal-water slurry,
It is already known to add various additives such as rust inhibitors, antioxidants, and dispersants to slurries. However, among these known additives.

There are very few examples that give very good results on coal concentration or viscosity, and that satisfy both this property and the stability of the slurry. For example, U.S. Patent No. 2,346,1
Reaction products of phosphoric acid esters, various amines, alkylene oxides and alkylphenols, naphthols and other acidic phosphates disclosed in Japanese Patent Publication No. 51-45600 and Japanese Patent Application Laid-Open No. 54-16511, etc. Additives such as salts of polycarboxylic acids such as polymethacrylic acid have poor viscosity lowering properties and are difficult to obtain highly concentrated slurries. Furthermore, additives such as fatty acid metal salts, as disclosed in U.S. Pat. The drawback is that it tends to cause agglomeration and sedimentation, and is inferior in long-term stability.

On the other hand, according to the additive of the present invention, the viscosity reducing function is large and it is possible to prepare a highly concentrated slurry. For example, a coal-water slurry with a high concentration of 65 to 80% by weight of coal powder can be easily obtained. In addition, this slurry has excellent long-term stability with less agglomeration and sedimentation over time.

Therefore, the coal-water slurry prepared using the additive of the present invention has advantages such as being easy and economical to transport by pipeline or other means, and being easily supplied to combustion equipment.

The term "blackstrap molasses" in this invention refers to the mother liquor obtained by crystallizing sucrose from cane juice, and generally contains sucrose and invert sugar as the main components, as well as molasses such as carmelized products, amino acids, and inorganic substances. It contains various sub-ingredients such as

The fermentation waste liquid discharged during the process of alcohol fermentation of this blackstrap molasses contains as solutes: 1) unfermented residual sugar;
) Sugar fermentation by-products such as glycerin, succinic acid, acetic acid, lactic acid, acetaldehyde, fusel oil, and esters;
3) Altered substances during the fermentation process of non-carbohydrates such as amino acids,
4) Non-fermented components such as denatured sugars and inorganic substances or their denatured substances during the fermentation process; 5) Products that contain drugs added during the fermentation process such as ammonium sulfate and ammonium phosphate or their denatured substances during the fermentation process. It is.

In this way, the solutes contained in the fermentation waste liquid have a more complex composition than the blackstrap molasses before alcohol fermentation, but generally the proportion of organic matter in the solutes is about 80% by weight. The rest is inorganic matter, and organic matter usually contains about 5 to 20% by weight of total sugar.

In this invention, it has been discovered that by using such a solute as an active ingredient in an additive for coal-water slurry, good results can be obtained in terms of viscosity reduction function and slurry stability. There are various aspects. Firstly, there is a method in which the fermentation waste liquid containing the solute is used as it is as an additive for a coal-water step, and secondly, the solute content in the fermentation waste liquid is generally about 10% by weight. The third method is to evaporate the fermentation waste liquid to dryness to extract the solute, dissolve it as it is or newly dissolve it in water, or optionally dissolve or disperse it in a medium other than water to make coal-water. There are methods such as adding it to slurry.

In addition, in each of the above methods, there is usually some suspended matter in the fermentation waste liquid, which settles during storage and becomes a precipitate, which may impair the commercial value of the additive. It is desirable to remove the above-mentioned floating matter in advance by appropriate means such as.

In addition, especially in the first and second methods above, the fermentation waste liquid is usually weakly acidic, and it is used in the coal-water slurry lJ.
When added to i, it may cause corrosion of handling equipment, so it is preferable to neutralize it with an alkali before use. This neutralization may be carried out until the pH of the neutralization process does not exceed 9, which is weakly alkaline. Even if such a neutralization treatment is performed, the effects of the present invention are not particularly adversely affected.

The additive of this invention can be added to the coal-water slurry in various usage modes as described above, but this additive may include gelling agents, rust preventives, preservatives, etc. as necessary. Of course, known additives for slurry may also be included.

The amount added to the coal-water slurry depends on its slurry characteristics,
In other words, although it varies depending on the particle size and concentration of coal powder or the type of active ingredient itself, generally the active ingredient is 0.1 to 5% by weight in the slurry, particularly preferably 0.5 to 3% by weight.
．． It is preferable to adjust the amount to 0% by weight. As the amount added increases, the viscosity lowering effect becomes greater and better results are obtained in terms of stability. However, if the amount exceeds a certain level, no further effect can be expected, which is economically disadvantageous.

The addition method is arbitrary, and an appropriate method may be selected depending on whether the coal powder is obtained by dry pulverization or wet pulverization. For example, in the dry pulverization method, it is preferable to add and mix the additive of the present invention in advance into water in which the pulverized powder is to be dispersed, and then add and mix the pulverized powder thereto. on the other hand,
In the wet pulverization method, it may be added in advance to the water used for wet pulverization, or it may be added during wet pulverization or after each pulverization.

In addition, if it is difficult to obtain a stable slurry using the additive of this invention by simply performing underwater pulverization or ordinary impeller stirring, mixing may be performed using a stirrer with strong shearing force such as a homogenizer or line mixer. It is better to do so.

The coal applicable to this invention may be subbituminous coal, bituminous coal, anthracite coal, etc., and is not particularly limited. Also,
This coal is pulverized by a dry pulverization method or a wet pulverization method to obtain a powder for water slurry, but the particle size of this powder is not particularly specified.

However, in order to prevent problems such as wear and blockage during pipeline transportation and burner combustion, the
It is preferable that the 0 mesh pass is 50% by weight or more,
More preferably, the content is 70% by weight or more.

Next, examples of the present invention will be described in more detail.

Example Composition of molasses discharged from an alcohol fermentation factory: Solid content 10.0% by weight Total sugar content in solid content 15.6% by weight Ash content in solid content 18.6% by weight Fermentation with waste liquor pH 4.8 The waste liquid was used as an additive for coal-water slurry (hereinafter referred to as additive A) of the present invention. In addition, 3 parts by weight of IJum (hydroxide) per 100 parts by weight of the solid content was added to the above fermentation waste liquid at room temperature, and the pH of the waste liquid was adjusted to 7.
The additive for coal-water slurry of the present invention (hereinafter referred to as Additive B) was obtained by neutralizing the mixture and removing suspended matter and precipitates using a centrifugal separator.

Using the additives of the above examples, a coal-water slurry was actually prepared according to Test Example 1-2 below, and the viscosity (25°C) and stability of this slurry were examined. The industrial analysis values of Miike charcoal (made in Japan) and Orchard Valley charcoal (American dust) used in this test were as follows.

Miike charcoal Orchard Valley coal specific moisture (wt%) 1.7 13.1 Ash content (wt%) 23.0 6.3 Volatile content
(wt%) 38.0 33.2 Fixed carbon (wt%') 37.3 47.4 The viscosity (25°C) of the obtained coal-water slurry was measured using a B-type viscometer, and the stability was determined as follows. I investigated the method. That is, the diameter sc
m, 6 from the bottom of a stainless steel cylinder with a height of 20 ci.
A take-out port with a stopper was provided at a position 12 cm from CI11, and the resulting coal-water slurry was poured into the cylinder up to a distance of 18 cm from the bottom and allowed to stand at room temperature for 2 weeks. Next, the upper layer above 12 cm from the bottom of the cylinder, 6
It was divided into a middle layer portion of ~12 cmEb and a lower layer portion below 6 cm, and the solid content of each layer was measured by the loss-on-drying method of leaving it in a drying mold at 105°C for 1 hour.

Test example 1 Miike charcoal is dry crushed to give 70% by weight of 200 mesh charcoal
of coal powder was obtained. The moisture content of this powder was 2% by weight. Next, take an aqueous solution 142.92 in which a predetermined amount of each additive of the example was dissolved in a 1/2 beaker, and mix it with a homomixer M type manufactured by Tokushu Kika Kogyo ■ at 300 to 500 rpm.
While stirring slowly at m
9 was gradually added, and after the addition was completed, the rotation speed of the homomixer was increased to s, ooo rpm and stirred for 10 minutes to obtain a coal-water slurry with a solid content of 70% by weight.

The following Table 1 shows the results of Test Example 1, and in the table, the reference example is the result when no additive was used. The amount added is the proportion of the additive (solid content) in the slurry. In addition, (*) in the table indicates that the viscosity of the slurry is extremely high, so the slurry cannot be taken out from the cylinder outlet.

This means that it was impossible to measure.

Table 1 Test Example 2 In a ball mill with a capacity of 51 (ball filling rate 30% by volume),
Take 4072 Orchard Valley coal with a moisture content of 14% by weight, coarsely ground to a particle size of about 2 rtrm, add 93 g of an aqueous solution in which a predetermined amount of each additive of the example is dissolved, and stir for 30 minutes to obtain coal. A coal-water slurry with a solid content of 70% by weight and a powder particle size of 200 mesh pass of 80% by weight was obtained.

The following Table 2 shows the results of Test Example 2, and in the table, the reference examples, amounts added, and (*) are the same as in Table 1 above.

As is clear from the test results in Table 2 and above, it can be seen that by using the additive of the present invention, a heterogeneous coal-water slurry with high concentration, low viscosity, and excellent long-term stability can be obtained. .

Patent applicant: NOF Corporation Agent: Patent Attorney Moto Kunio Negi S8:

Claims (1)

[Claims] (1) An additive for coal-water slurry whose active ingredient is a solute contained in the fermentation waste liquid discharged in the alcohol fermentation process of blackstrap molasses.