JPS5968392A - Additive for coal/water slurry - Google Patents

Abstract

PURPOSE:The titled additive having improved viscosity reducing ability and giving a desirable effect on the stability and shear stability, which is prepd. by incorporating a copolymer of a monomer mixture comprising maleic anhydride, an alpha-olefin and a specified compd. CONSTITUTION:An additive for coal/water slurry contg. as an effective component a copolymer of a monomer mixture comprising (A) maleic anhydride, (B) an alpha-olefin of the formula (wherein R1 is H or methyl; R2 is H, 1-30C alkyl, alkenyl, phenyl or 1-4C alkyl-substd. phenyl) and (C) at least one member selected from acrylamide, vinyl ether, vinyl ester and vinylsulfonic acid, or an alkali metal salt, ammonium salt or lower amine salt of an amidated compd. thereof. Pref. component B includes ethylene, propylene, 1-butene, and isobutylene. Pref. component C includes acrylamide, vinyl ether, vinyl ester, vinylsulfonic acid.

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 shape, coal has long been dethroned by oil as a fuel, or after the oil crisis, coal was replaced by a coal-oil mixed fuel (C: OM).
), there have been many attempts to treat coal as a fluid by turning it into powder and mixing it with a medium. However, in the case of coal-filtrate-oil mixed fuel, it is impossible to avoid the disadvantage that the slurry is about half full, and the development of another slurry fuel is desired.

In recent years, slurry, a fluid in which water is used as a medium and highly concentrated coal is dispersed, has been made suitable for transportation by pipeline or tanker, and has also been used 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 has a high coal concentration and low viscosity, and has excellent long-term stability without causing coal powder agglomeration or sedimentation. It is also desired that the slurry be able to maintain stability even when mechanical shearing force is applied.

By the way, it is already known that various additives such as rust preventive agents, antioxidants, and dispersants are added to the slurry in order to modify the properties of the coal-water slurry. However, among these known additives, there are hardly any that give very good results on coal concentration or viscosity and satisfy both this property and the stability of the slurry. Examples include U.S. Pat.
Additives such as phosphoric acid esters, various amines, reaction products of alkylene oxides with alkylphenols, naphthols, and other acidic phosphates, and salts of polycarboxylic acids such as polymethacrylic acid disclosed in the above publication do not reduce viscosity. It has poor functionality and is difficult to obtain high concentration slurry.

Also, JP-A-52-71506 and JP-A-53-5
The likunin sulfonate proposed in JP-A No. 81, the naphthalene sulfonate and the formaltehyde condensate salt of naphthalene sulfonic acid proposed in JP-A-56-21636, etc. are more effective than the above-mentioned additives. It has a viscosity-reducing function and contributes to the stability of the slurry to some extent, but there is still room for improvement in these properties, and the disadvantage is that when mechanical shearing force is applied to the resulting slurry, its stability is extremely reduced. Therefore, it could not be said to be satisfactory for practical use.

The present invention aims to provide an industrially useful additive that has an improved viscosity-reducing function compared to the above-mentioned proposals and also provides good results in the standing stability and stability against shearing forces of slurry. The gist of this is that A) maleic anhydride, and 13) the following general formula; C)
An alkali metal salt, ammonium salt or lower amine salt of a copolymer of a mixed monomer containing as an essential component at least one selected from acrylamides, vinyl ethers, vinyl esters and vinyl sulfonic acids, or an amidation thereof. An additive for coal-water slurry containing as an active ingredient.

According to such an active ingredient, it is possible to prepare a highly concentrated slurry due to its excellent viscosity reducing ability, and it is easy to obtain a coal-water slurry with a high concentration of coal powder, for example, 60 to 80% by weight. This slurry has excellent static stability with less oral agglomeration and sedimentation, and also has excellent shear force stability without becoming compacted even when subjected to mechanical shear force. becomes.

Slur IJ-, which has excellent stability against shearing force, is
Assuming that this is manufactured overseas, transported by long-distance pipelines or long-term ships, and then consumed in Japan,
It is very advantageous to maintain sufficient stability of the slurry against mechanical shear forces during transportation. As described above, 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. can get.

The mixed monomer used to obtain the copolymer in this invention contains the above-mentioned components A, B, and C as essential components, and optionally contains other monomers copolymerizable with these components.
Among these, specific examples of component B include ethylene, propylene, 1-phthene, inbutylene,
Examples include 1-hexene, diisobutylene, -octene, butadiene, styrene, and P-methylstyrene. In addition, as component C, acrylamide, methacrylamide,
Acrylamides such as diacetone acrylamide; methylhinyl ether, isopropyl vinyl ether, [
- Hinyl ethers such as butylhinyl ether, 2-ethylhexylhinyl ether, and phenylhinyl ether; hinyl esters of hinyl acetate, hinyl caproate, hinyl laurate, and vinylnato stearate: vinyl sulfonic acid, allyl sulfonic acid, styrene sulfone There are hinyl sulfonic acids such as acids, and one or more types are selected from these.

The JJ authors found that the alkali metal salt, ammonium salt, or lower amine salt of the copolymer of at least the A, B, and C3 components or their amides lowers the viscosity of the coal-water slurry and stabilizes it on standing. It has been found that this method not only imparts properties but also provides particularly good results in imparting stability against shear forces.

The copolymerization of a mixed monomer containing the three essential components A, B, and C proceeds by normal radical polymerization under normal pressure or under pressure, and the copolymerization ratio of the essential components is 10 to 50% of the A component.
mol%, better < is 30 to 50 mol%, C component is 1 to 3
It may be selected such that the remaining amount is 0 mol%, preferably 1 to 20 mol%, and the remainder is component B. If it deviates from this range, the performance of the additive of the present invention ultimately obtained is undesirable. The molecular weight of the copolymer is 500 to 50,000
and preferably 1,000 to 20,000.

One of the active ingredients of the additive of this invention is an alkali metal salt, ammonium salt, or lower amine salt of the above copolymer, and the other is an alkali metal salt, ammonium salt of an amidide of the above copolymer. or a lower amine salt. The amidated product is obtained by reacting the acid anhydride group of the copolymer with ammonia or a lower primary or tertiary amine, and one of the acid anhydride groups is partially amidated and the remainder becomes a carboxyl group. Examples of lower primary or tertiary amines used in the amine conversion include methylamine, cyphthylamine, ethylamine, ethylamine, propylamine,
These include dipropylamine, methylamine, cyphthylamine, monoethanolamine, jetanolamine, and morpholine.

Alkali metal salts of the copolymer or its amidation product include lithium salt, sodium salt, and potassium salt, and lower amine salts include lower primary or tertiary amines used in the amidation, trimethylamine, and triethylamine. There are tertiary amines such as tripropylamine, tributylamine, and triethanolamine.

The additive of this invention can be used by selecting one or more of the above-mentioned two active ingredients and using it as it is or in a state where it is included in a medium such as water or alcohol. I can do it. Such additives include
If necessary, known slurry additives such as gelling agents, rust preventives, and preservatives may 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 the coal powder or the type of the active ingredient itself, generally the active ingredient is 0.01 to 5% by weight in the slurry, particularly preferably 0.05% by weight.
It is preferable to adjust the amount to 1.0% 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, the additive of the present invention may be added and mixed in advance into the water in which the pulverized powder is dispersed, and then the pulverized powder is added and mixed. 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 or after wet pulverization.

If it is difficult to obtain a stable slurry using the additive of this invention by submerged pulverization or normal impeller stirring, use a stirrer with strong shearing force such as a homogenizer or line mixer. It is best to mix it.

The coal applicable to this invention may be sub-bituminous coal, bituminous coal, anthracite coal, etc., and is not particularly limited, but coal with fewer pores is preferable. Further, 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 also not particularly specified. However, in order to prevent druffles such as abrasion and clogging during pipeline transportation and burner combustion, it is usually preferable that the 200 mesh pass force is 50% by weight or more, and more preferably 70% or more.

At the same time, examples of the present invention will be described to provide a more specific explanation.

EXAMPLE The above-mentioned components A, B, and C were radically copolymerized in a conventional manner or under pressure, and after the copolymerization, amidation and salt formation treatments were performed to form the samples shown in Table 1 below.
The additive milling material for coal-water slurry of this invention consisting of Nos. 1 to 10 was obtained. ~IAn in Table 1 is an abbreviation for maleic anhydride, and MW means average molecular weight.

Comparative Examples Samples j611 to 16 and sodium polyacrylate (Mw 3,000) (sample) 161 shown in Table 2 below
7), Sodium oleate (sample/;, 18),
-1-7 Sodium formaltehyde talenesulfonate condensate (average degree of condensation 4) (sample 16.19) was used as an additive for coal-water slurry different from this invention.

Using each of the additives in Examples and Comparative Examples, a coal-water slurry was actually prepared according to Test Examples 1 and 2, and if the slurry had a viscosity (25°C) and stability, it was The influence of force on stability was investigated. The industrial values of Wanbo charcoal (produced in Ausdoor) and Balmer charcoal (produced in Kanata) used in this test are as follows.

Wanho coal Balmer coal with water 1. 'ri-%) 3.0 1.5
- Minutes (bow'11;%) 14.0 17.0
- Recording (411%) 32.0 20.0 Constant carbon (11 BIH%) 50.2 62.0 Viscosity of the obtained coal-water slurry (25 was measured using a type 3 viscometer and allowed to stand still) Stability was investigated using the following method: A stainless steel cylinder with a diameter of 5 cm and a diameter of 20 mm was provided with outlet ports with stoppers at positions 6α and 12 from the bottom.
The resulting water slurry was poured from the bottom of the cylinder at 18
It was filled to the brim and allowed to stand at room temperature for one week. 1, Upper part above 12 cm from the bottom of the cylinder, 6-12c1
divided into a middle part of n and a lower part below 6 cm,
The solid content of each layer was measured by the loss on drying method, which was performed by leaving the layer in a drying mold at 105''C for 1 hour.

In addition, stability due to shear force was determined by the following method. That is, the obtained coal-water slurry was
cm, height 15 on into a 1e beaker 800
m1! Insert the impeller with a blade diameter of 2c7 to the 4th line.
It was set at the 00 me position and stirred at 20 rpm for 24 hours. After the stirring was stopped, the impeller was removed and left as it was for 10 days. After letting it stand for 1 degree, tilt the beaker and pour out the slurry. If all of the slurry flows out, hard sediment has formed at the bottom and cannot be easily taken out with a spatula.
, ×, and in the case of ◎, it was determined that a slurry strong against shearing force was obtained.

Test Example 1 Wanbo coal was dry-pulverized to obtain coal powder containing 200 mesh passes of 70% by weight. The water content of this powder is 4% by weight (
(including adhering water). First, take 135.4 g of an aqueous solution in which predetermined amounts of each of the additives of the above Examples and Comparative Examples were dissolved in a 1β beaker, and
300 to 500 r using Homo Mixer M type manufactured by Co., Ltd.
While stirring slowly at pm, coal powder 364.
61i' was gradually added, and after the addition was completed, the rotation speed of the homomixer was increased to 5.00 rpm and stirred for 10 minutes, thereby obtaining a coal-water slurry with a solid content of 70%.

Table 3 below shows sample No. 161 as an additive of this invention.
These are the results of Test Example 1 when Samples 11 to 19 were used as additives for Samples 11 to 10 and Comparative Examples.

In the table, the amount added is expressed as the proportion of the additive (solid content) in the slurry. In addition, the reference example is the result when no additive was used at all, and the viscosity of the slurry in (rice) in the table is very high, so the slurry could only be taken out from the outlet of the Norinter, and the measurement Indicates that it was impossible.

Test Example 2 364.6 g of Balmer charcoal with a water content of 4 wt% (including adhering water), coarsely pulverized to a particle size of approximately 2πm, was placed in a ball mill with a capacity of 5e (pole filling rate: 30% by volume), and the above-mentioned Water-soluble 7i121.5 in which predetermined amounts of each additive are dissolved
By adding g and grinding for 30 minutes, the particle size of the coal powder was made to be 80% by weight, with a solid content of 72
A coal-water slurry of % by weight was obtained.

Table 4 shows samples 16 and 2 as additives of this invention.
These are the results of Test Example 2 when Samples j611 and 14 were used as additives in Samples J611 and 5 and Comparative Example.

In the table, the amounts of additives added, reference examples, and (2) are the same as in Table 3.

As is clear from the above test results, by using the additive of the present invention, it is possible to produce a homogeneous product with high hardness, low viscosity, and excellent not only static stability but also shear J stability. It can be seen that a coal-water slurry is obtained.

Claims (1)

[Claims] (1) A) Maleic anhydride and B) General formula: % formula % (In the formula, kl is hydrogen or methyl group, k2 is hydrogen, alkyl group or alkenyl group having 1 to 30 carbon atoms, phenyl group, carbon C) at least one olefin represented by C) which is a phenyl group substituted with an alkyl group of numbers 1 to 4;
An alkali metal salt, ammonium salt or lower amine salt of a copolymer of a mixed monomer containing as an essential component at least one selected from acrylamides, vinyl ethers, vinyl esters and vinyl sulfonic acids, or an amidation thereof. An additive for coal-water slurry containing as an active ingredient.