JPS5968393A - 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, (meth)acrylic acid 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) acrylic acid and/or methacrylic acid and (C) at least one member selected from alpha-olefins of the formula (wherein R1 is H or methyl; R2 is H, 1-30C alkyl, alkenyl, phenyl or 1-4C alkyl-substd. phenyl), vinyl ethers, acrylamides, vinylpyridines, vinylethers, vinyl-sulfonic acid and adducts of acrylic or methacrylic acid with an alkylene oxide, or an alkali metal salt, ammonium salt or lower amine salt of an amidated compd. thereof.

Description

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

Due to its solid form, coal had long been dethroned as a fuel by oil, but the oil crisis forced people to look at coal as a fuel, and coal-oil mixed fuel (coal-oil mixed fuel)
As exemplified by Nt), 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, attempts have been made to use water as a medium to create slurry as a fluid in which coal is dispersed at a high concentration, making it suitable for transportation by pipeline or oil tanker, and furthermore, attempting to use it as an alternative fuel to oil in various boilers. Attempts are being made. In the case of this slurry, although 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 has been known to add various additives such as rust preventives, antioxidants, and dispersants to a coal-water slurry in order to modify its properties. However, among these known additives, there are few that can 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. Pat.
Additives such as phosphoric acid esters, various amines, reaction products of alkylene oxides with alkylphenols, naphthols, and other acidic phosphates, and salts of polycarphonic acids such as polymethacrylic acid disclosed in the above publications include It is difficult to obtain highly concentrated slurry due to poor viscosity reduction function.

Also, JP-A-52-71506 and JP-A-53-5
8] The likunin sulfonate proposed in JP-A No. 56-21636, the natutalenosulfonate and the salt of the formaltehyde condensate of natutalenosulfonic acid proposed in JP-A-56-21636 are the above-mentioned additions. It has a viscosity-reducing function compared to other agents and contributes to the stability of the slurry to some extent, but there is still room for improvement in these properties, and furthermore, when mechanical shearing force is applied to the resulting slurry, its stability becomes extremely low. Because of the disadvantages of lowering the temperature, 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 proposal, and also provides good results in the static stability and stability against shearing forces of slurry. The gist of this is that A) maleic anhydride, B) at least one selected from acrylic acid and methacrylic acid, and the following a-
At least one selected from the components g and the general formula with a); 1)) Vinyl esters, lyacrylamides (rivinylpyridines e) vinyl ethers D, vinyl sulfonic acids, acrylic acid or methacrylic An additive for coal-water slurry containing as an active ingredient an alkali metal salt, ammonium salt or lower amine salt of a copolymer of mixed monomers containing as an essential component of an alkylene oxide adduct of acid or an amidated product thereof.

According to such an active ingredient, the preparation of highly concentrated slurry becomes possible due to its excellent viscosity reducing ability, and it is possible to easily obtain a highly concentrated coal-water slurry of 60 to 801% from coal powder, for example, and This slurry has excellent static stability with suppressed oral 211 and sedimentation, and also has excellent shear force stability without compaction even when subjected to 1414 shear force. Become something.

Slurry with excellent stability against shearing forces is expected to be manufactured overseas and consumed in Japan after being transported by long-distance/long-distance line or ship for a long period of time. This is very advantageous because it can maintain sufficient stability of the slurry against forces. 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. It will be done.

The mixed monomer used to obtain the copolymer in this invention contains the above-mentioned three components A, B, and C as essential components, and optionally contains other monomers copolymerizable with these components, or Specific examples of each C component selected from among components 1 to 2 are as follows.

First, the α-olefin of component C includes ethylene, propylene, 1-phthene, isophthylene, ■-hexene, diisobutylene, 1-octene, phthalene, styrene, P
- Methystyrene tocal.

In addition, the vinyl esters of component l) include vinyl acetate, vinyl caproate, vinyl laurate, vinyl stearate, etc., and the acrylamides of component C include:
Acrylamide, methacrylamide, diacetone acrylamide, etc. are mentioned, and the vinylpyridines of the d component include 2-vinylpyridine, 4-vinylpyridine, etc., respectively.

Vinyl ethers as component C include methyl vinyl ether, isopropyl vinyl ether, -methyl vinyl ether, 2-ethylhexyl vinyl ether, phenyl vinyl ether, and examples of vinyl ether as component C include hinyl sulfonic acid, allyl sulfonic acid, styrene sulfonic acid, etc. Further, examples of the alkylene oxide adduct of acrylic acid or methacrylic acid as component g include ethylene oxide adducts of acrylic acid, propylene oxide and ethylene oxide adducts of methacrylic acid, and the like.

The inventors found that the alkali metal salt, ammonium salt, or lower amine salt of the copolymer of the three components or its amidation not only reduces the viscosity of the coal-water slurry and imparts static stability, In particular, it has been found that it brings about very good results in imparting stability against shear forces.

The copolymerization of the mixed monomers containing the above A, B, and C3 components as essential components proceeds by normal radical polymerization under normal pressure or pressure, and the copolymerization ratio of the essential components is 10 to 50% of the A component.
Molch, preferably 30 to 50 moles, C component is 1 to 4
It may be selected such that the mole ratio is 0, preferably 1 to 20 molar, and the remainder is the B component. Outside this range, the performance of the additive of the present invention ultimately obtained is undesirable.

The average molecular weight of the copolymer is 500 to 50,000, 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 polymer, and the other is an alkali metal salt, ammonium salt, or lower amine salt of the above copolymer amidide. It is 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. Lower primary or tertiary amines used in amidation include methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, methylamine, dibutylamine, monoethanolamine, jetanolamine, and morpholine. be.

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. , tertiary amines such as tripropylamine, tributylamine, triethanolamine, etc.6
Roru.

The additive (+1jll) of this invention is selected from one or more of the above-mentioned two active ingredients and used as it is or in a state where it is included in a medium such as water or alcohol. Such additives may contain known additives for slurry such as a kelizing agent, a rust preventive agent, and a preservative, if necessary.

The amount added to the coal-water slurry depends on its slurry characteristics,
In other words, it varies depending on the particle size and concentration of coal powder or the type of active ingredient itself, but generally the active ingredient is slurry 90701-5% by weight, particularly preferably 0.0%.
It would be good to have a weight ratio of 5 to 1.0. As the amount added increases, the viscosity lowering effect is good for dogs, and good results can be obtained even with one box 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 the clear water in which the pulverized powder is dispersed, and then add the pulverized powder thereto and mix. 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 during pulverization 1.
It may be added in a strange manner.

In addition, if it is difficult to obtain a stable slurry using the additive of this invention by underwater pulverization or normal impeller stirring, use a stirrer with strong shearing force such as a homogenizer or line mixer. Better to mix.

The coal to be applied to this invention may be sub-bituminous coal, bituminous coal, anthracite, etc. (although there are no restrictions on this, coal with fewer pores is preferable. Grind it using a grinding method to make powder for water slurry, or
The particle size of this powder is also not particularly specified. However, in order to prevent druffles such as abrasion and blockage during pipeline transportation and burner combustion, normally 200 mesh, NIL
It is preferable if the distance is 50 cities, and even more preferable if it is 70 cities or more.

Finally, embodiments of the present invention will be described to provide a more detailed explanation.

New Year's Eve (Dari) The above A component, B component, and C component are radically copolymerized under normal pressure or under pressure, and after the copolymerization, amidation and salt formation treatments are performed to produce the samples shown in Table 1 below. 1-1
An additive for coal-water slurry of this invention consisting of 7 was obtained. M A n in Table 1 is an abbreviation for maleic anhydride, and M W means average molecular weight.

Comparative Example Samples shown in Table 2 below, angles 18 to 22 and sodium polyacrylate (MW 3,000) (sample height 23)
, sodium oleate (sample A24), and sodium naphthalene sulfonate formaldehyde condensate (average degree of condensation 4) (sample height 25) were used as additives for coal-water slurry different from the present invention.

Table 2 Coal-water slurry was actually prepared according to Test Examples 1 and 2 below using the additives of the above Examples and Comparative Examples.
The influence of the viscosity (258C), static stability, and stability due to shear force of this slurry was investigated. The industrial analysis values of Wanbo charcoal (produced in Australia) and Balmer charcoal (produced in Kanata) used in this test are as follows.

One No. Shisai Noni Lure Marutei Intrinsic moisture (parts by weight) 3.0 1.5 Ash content (parts by weight)
14.0 17.0 Volatile content (parts by weight) 32.0
20.0 Fixed carbon (parts by weight) 50.2 6
2.0 The viscosity of the obtained coal-water slurry (25°
C] was measured using a Type 11 viscometer, and the static stability was examined using the following method. That is, a stainless steel cylinder with a diameter of 5 cm and a height of 20 cm was provided with outlet ports with stoppers at positions 6 cm and 12 cm from the bottom, and the obtained coal-water slurry was poured into the cylinder to a point of 18 G from the bottom, and the mixture was heated at room temperature. It was left undisturbed for one week. The loss on drying method involves dividing the cylinder into an upper layer above 12 cm from the bottom, a middle layer between 6 to 12 cm, and a lower layer below 6G, and leaving the solid content of each layer in a drying mold at 105°C for 1 hour. It was measured with

Further, the stability due to shear force was determined by the following method. That is, the obtained coal-water slurry was heated to a diameter of 1.
0.5 cm, height 15-II! into the beaker of 8
Insert up to the 00rnl line and insert an impeller with a blade diameter of 2σ into the
Set it to the 00ηJ position and run it for 24 hours at 2QQrpm.
I stirred 1. After the stirring was stopped, the impeller was removed and left as it was for 3 days. After letting it stand for 3 days, put the slurry in a beaker and pour out the slurry. If all the slurry flows out, a hard sediment will form at the bottom and it will not be possible to take it out easily with a spoon, etc., respectively.
It is represented by ×, and in the case of ◎, it was determined that a slurry strong against shearing force was obtained.

Test Example 1 Wanpo coal was dry-pulverized to obtain coal powder containing 200 mesh passes of 70% by weight. The moisture content of this powder is 4% by weight
(including attached water). Next, take aqueous solution 13541 in which predetermined amounts of each of the additives of Example 675 and Comparative Example were dissolved in a beaker of IE, and use Homomixer M type (Tokushu Kika Kogyo @) to prepare the aqueous solution 13541 at 300 to 500 rP.
Coal powder 364 of 2, "Do not stir slowly."
．． 6F was gradually added, and after the addition was completed, the homomixer was rotated at 5.000 rpm and stirred for 10 minutes to obtain a coal-water slurry with a solid content of 70% by weight.

The following Table 3 shows sample heights of 1 to 1 as additives of this invention.
7 and as an additive for comparative example.
These are the results of Test Example 1 of the above test when using .

In the table, the amount added is shown as the proportion of the additive (solid content) in the slurry.The reference example is the result when no additive was used at all, and The viscosity was so high that the slurry could not be taken out from the outlet of the cylinder, indicating that it could not be measured.

Test Example 2 In a ball mill with a capacity of 51 (ball filling rate: 30% by volume), Balmer charcoal of 364.69% with a moisture content of 4% (including attached moisture), coarsely pulverized to a particle size of approximately 2trvn, was placed, and the above-mentioned Water-soluble 71i121 in which additives of
．． 55' was added and pulverized for 30 minutes to obtain a coal-water slurry with a solid content of 72 wt' and 14%, in which the particle size of the coal powder was 200 mtsunyupas 80 wt 1i%.

Table 4 shows samples 2 and 8 respectively as additives of this invention.
, and the results of Test Example 2, the above test, when Samples 4618 and 21 were used as additives in Comparative Example. In the table, the amounts of additives added, reference examples, and (4) are the same as in Table 3.

As is clear from the above test results, by using the additive of the present invention, a homogeneous coal-water product with high concentration and low viscosity, which exhibits not only static stability but also stability against shear force, can be produced. You know what you're getting from the slurry.

Claims (1)

[Claims] (1) nor]maleic anhydride; B) at least one selected from acrylic acid and methacrylic acid;
C) At least one selected from the following a-g components, and a) the following general formula; (alkyl group, alkenyl group, phenyl group, or phenyl group substituted with an alkyl group having 1 to 4 carbon atoms) Vinyl esters of α-olefins 1) C) Acrylamides, vinyl pyridines e) Vinyl ethers, 0 vinyl sulfonic acids, etc. A 5-charcoal-water slurry containing as an active ingredient a copolymer of mixed monomers containing as an essential component an alkylene oxide adduct of acrylic acid, meth, or 7-lyric acid, or an alkali metal salt, ammonium salt, or lower amine salt of its amidation. additives for