CA1339839C - Polyether glycol esters of polycarboxylic acids as rheological additivescoal-water slurries - Google Patents
Polyether glycol esters of polycarboxylic acids as rheological additivescoal-water slurriesInfo
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- CA1339839C CA1339839C CA000524143A CA524143A CA1339839C CA 1339839 C CA1339839 C CA 1339839C CA 000524143 A CA000524143 A CA 000524143A CA 524143 A CA524143 A CA 524143A CA 1339839 C CA1339839 C CA 1339839C
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Abstract
Coal-water slurries containing a rheological additive are disclosed. The rheological additives employed for the preparation of the present coal-water slurries are the reaction product of a polycarboxylic organic acid and a polyether glycol. Salts of these reaction products may also be employed. The rheological additive is employed in an amount from about 0.1 to about 4 percent by weight of the slurry, the slurry having from about 60 to about 80 percent by weight solids, the balance being water.
Description
133983~
POLYETHER GYCOL ESTERS OF
POLYCARBOXYLIC ACIDS AS RHEOLOGICAL
ADDITIVES FOR COAL-WATER SLURRIES
This invention relates to a coal-water slurry having a rheological additive which is the reaction product of a polycarboxylic organic acid and a polyether glycol. The ester reaction product is employed in an amount from about 0.1 to about 4~ by weight of the coal-water slurry, the slurry having from about 60 to about 80% by weight of solids, the balance being water.
In recent years a great deal of interest has developed in utilizing coal-water slurries in lieu of oil for electric power generation not only because of the lower cost of coal but also because of its availability.
Coal-water slurries have been produced with solids contents of about 60 to about 75~ which are fluid and handle in about the same way as petroleum fuels. These coal-water slurries may be burned directly without need of dewatering the mixture. The heat generated during combustion is suffi-ciently high so that the water in the slurry does not prevent it from being used to generate power. Naturally, as the solids of the coal-water slurry increase, the fuel value of the slurry also increases. For this reason, slurries having less than about 50 to 55% solids are unsuitable primarily for economic reasons.
One of the difficulties encountered with coal-water slurries at a solid content of about 60% and higher is that the dispersion of coal in water be~omes an immobile mass and when burned it has to be handled in the same manner as lump coal. Handling in this respect includes not only ~33983~
transportation of the coal from the mine source but also the delivery of the coal to a combustion chamber such as the firebox of a steam boiler. Unless coal-water slurries have the same liquidity as oil at these high solids content so that they may be transported by pipeline and injected into a firebox by spraying, the advantage of using a liquid carrier (i.e., water) for the coal is lost. Stated otherwise, the particles of coal in the slurry at these higher solids levels tend to convert the liquid carrier (water) into a plastic mass whereby the advantage of employing a liquid carrier is lost.
The prior art has overcome some of-these diffi-culties by providing additives which may be used in relative-ly small amounts to assure that the coal-water slurry at high solids content is fluid. Examples of these additives are given by Kovacs in U.S. Patent 4,435,306 Sakaria U.S. Patent 4,398,919 and in European Patent Application 0131558.
Coal-fuel oil slurries containing a dispersing agent are also described by Schmolka et al. in U.S. Patent 4,288,232, Naka et al. U.S. Patent 4,251,229 and Shimizu et al. U.S. Patent 4,187,078-The present invention relates to a coal-water slurry having a novel rheological additive comprising the reaction of:
(a) a polycarboxylic organic acid having from about 16 to 60 carbon atoms and form 2 up to 4 carboxyl groups with (b) a polyether glycol having recurring oxyalkylene groups containing up to 4 carbon atoms and having a molecular weight from about 1,000 to about 20,000; the mole 3~ ratio of said polyether glycol to said polycarboxylic acid ranging from about 1:1 to n-1:1 where n is the number of carboxyl groups in the polycarboxylic acid.
The polyether glycol is selected from the group consisting of polyethylene glycol, polypropylene glycol, and poly(ethylene-propylene) glycol and the polycarboxylic acid is selected from the group consisting of dimer acids, trimer acids, adducts of unsaturated monocarboxylic acids or dimer acids with maleic anhydr~de in a molar ratio of about 1:1, adducts of linoleic acid or similar unsaturated monocarboxylic acids with acrylic-type acids in a molar ratio about 1:1 and adducts of olefins having about 12 to about 40 carbon atoms with maleic acid or maleic anhydride in a molar ratio of about 1:1. Polyethylene glycol having a molecular weight from about 3,000 to 12,000 is particularly useful for the preparation of the rheological additives of this in-vention. The acid value of the rheological,additive istypically 25 to 75 percent of the acid value of the polycarboxylic acid/polyether glycol mixture before reaction.
According to another feature of an embodiment of the present invention all or a portion of the remaining carboxyl groups are converted to a salt form. Salts of ammonia and the group IA or IIA metals, especially sodium or potassium are particularly useful for this purpose.
The rheological additive is employed in an amount from about 0.1 percent to about 4 percent and, more pref-erably, from 0.25 to 1.5 percent in slurries containing from about 60 to about 80 percent by weight solids.
The rheological additives of this invention are utilized in coal-water slurries and are obtained by reacting a polycarboxylic organic acid with a polyether glycol to rorm 3~ an ester. The acids have form about 16 to about 60 carbon 133~8~9 atoms, especially from 21 to 54 carbon atoms, and from 2 up to about 4 carboxyl groups. The acids may be either dimer acids, trimer acids, adducts of unsaturated monocarboxylic acids or dimer acids with maleic anhydride in a molar ratio of about 1:1, adducts of linoleic acid and similar unsatura-ted monocarboxylic acids with acrylic-type acids in a molar ratio of about 1:1 or adducts of olefins having about 12 to about 40 carbon atoms with maleic acid or maleic anhydride in a molar ratio of about 1:1.
Dimer acids are known in the art and described by Barret et al. in U.S. Patent 2,793,220 and Myers et al. U.S.
patent 2,955,121. Trimer acids are also known in the art and are described by Barrett et al. in U.S. Patent 3,097,220.
The dimer acid is obtained by oligomerizing an unsaturated 18 carbon atom naturally occurring unsaturated acyclic monocarboxylic fatty acid such as oleic acid, linoleic acid, linolenic acid and the like to obtain a 36 carbon atom dicarboxylic acid whereas the trimer acid is obtained by oligomerizing the foregoing unsaturated monocarboxylic acids to obtain a 54 carbon acid tricarboxylic acid. In both of these reactions, other products are obtained; however, the reaction is conducted in a manner so that the reaction product is principally the dimer acid or the trimer acid.
other unsaturated acyclic monocarboxlyic acids having at least one ethylenically unsaturated position and from about lO to about 22 carbon atoms can also be used to make the polycarboxylic acids of the present invention. These include decenoic, undecenoic, pentadecenoic, hexadecenoic acids and the like. unsaturated acyclic monocarboxylic acids of the above types may be obtained from natural fats and oils such as tall oil, linseed oil, tung oil, soy oil, rapeseed oil, corn oil, fish oil, beef tallow and mixtures thereof.
Dimer acid prepared as described in the foregoing references containing 75~ or more of dimer acid is preferred whereas trimer acid prepared according to the foregoing references having 60% of more of trimer acids is preferred.
Mixtures of dimer acid and trimer acid are also useful and advantageously employed.
Adducts of maleic anhydride (or acid) with unsa~ 9839 ated monocarboxylic acid and dimer acids are known in the art and are described in U.S. Patents 2,902,499 and 2,975,133.
These adducts are prepared by heating maleic anhydride and an 5 unsaturated acid at a temperature from about 100~C to about 300 C until the addition reaction is completed. The molar ratio of the maleic anhydride to unsaturated acid is generally about 1:1.
A 21 carbon atom dicarboxylic acid designated lO Westvaco 1550 (trademark) may be employed as the polycarboxy-lic acid and comprises the addition product of an 18 carbon atom monocarboxylic unsaturated acid and acrylic acid. Equi-valent unsaturated monocarboxylic acid having at least two ethylenically unsaturated positions and from about 10 to 15 about 22 carbon atoms reacted with an acrylic-~ype acid to produce a dicarboxylic acid may also be employed as the polycarboxylic acid. The acrylic-type acids, as referred to herein, include angelic acid, tiglic acid, senecioic acid, crotonic acid, isocrotonic acid, vinylacetic acid, methacry-20 lic acid and the like mixtures thereof. The -6- 1~39~39 polycarboxylic acid can also be an adduct of maleic acid or maleic anhyride with an olefin, where the olefin has from 12 to 40 carbon atoms and one or two unsaturated positions.
Polyether glycols reacted with the above-described polycarboxylic acids to obtain the reaction product of the present invention comprise higher molecular weight poly (lower oxyalkylene) glycols. The molecular weight of the polyether glycol ranges from about l,000 to about 20,000 and, more preferably, from about 3,000 to about 12,000.
They are comprised of recurring oxyalkylene groups containing up to about 4 carbon atoms and preferably from 2 to 3 carbon atoms. Polyethylene glycol having a molecular weight from about 3,000 to about 12,000 is particularly useful for the preparation of the rheological additives of the present invention, however, polypropylene glycol poly(ethylene-propylene) glycols within the above-described molecular weight ranges are also useful.
The various polyether glycols noted herein may have either a broad or a narrow molecular weight distribution so long as the molecular weight, on average, is within the aforementioned ranges. These ranges apply not only to polyether glycols falling within the range, but also to polyether glycol mixtures having an average molecular weight with the aforesaid range. The commercial glycols employed according to the present invention are within the aforemen-tioned molecular weight ranges and the molecular weights thereof are average molecular weights. Some commercial polyethylene glycols that may be employed according to the present invention have average molecular weights of 1000, 3o _7_ ~ 3983~
1 3350~ 8000, and 20000 and are sold under the trademark Carbowax 1000, 3350, 8000 and 20000.
Lower alkoxy poly (lower oxyalkylene) glycols, i.e., wherein one of the terminal hydroxyl groups is "capped"
with an alkyl group having from 1 to about 4 carbon atoms may also be employed. These lower alkoxy poly (lower oxyalkylene) glycols also are within the molecular weight range as defined above for the polyether glycols. The terminal hydroxyl group generally is "capped" with a methyl group, such as methoxpolyethylene glycol.
Mixtures of any of the polyether glycols noted herein may also be used.
Although the polycarboxylic acid and polyether glycol may be reacted to almost completely esterify the acid, in a preferred embodiment, the molar ratio of polyether glycol to polycarboxylic acid is about 1:1 to n-l:l, wherein n is the number of carboxyl groups in the polycarboxylic acid. The polyether glycol and polycarboxylic acid are reacted to form an ester in which the acid value (AV) of the ester is 25 percent to 75 percent of the acid value of the reactant mixture before esterification. Some unreacted carboxyl groups remain in the ester which in some applica-tions improves the performance as rheological additives.
The rheological additives of the present invention are reaction products of the aforementioned polycarboxylic acids and polyether glycols and are produced in accordance with conventional esterification procedures. Some unreacted glycol and acid remains~in the reaction product and are not removed. Polymerization is avoided by the use of the afore-mentioned molar ratios and controlled degree of reaction. By 13~9839 proceeding in this manner, the esters thus produced will haveunreacted carboxylic acid groups.
According to another feature of an embodiment of the present invention, all or a portion of the remaining carboxylic acid groups are converted to a salt form, These salts of the partial ester are also useful as rheological additives. salts of ammonia and the Group IA or Group IIA
Metals of the Periodic Table of the Elements, especially sodium or potassium metals, are particularly useful. The salts may be formed by reacting the partial ester with the hydroxides of the aforementioned metals or with ammonium hydroxide in an amount from about 50% to about 100% of the free carboxylic acid groups of the partial ester, Salts may also be obtained from alkanolamines or heterocyclic nitrogen compounds having up to about 10 carbon atoms and 1 or 2 nitrogen atoms by reacting the partial ester with the alkanolamine or heterocyclic nitrogen compound in a conventional manner, Various heterocyclic nitrogen compounds that may be employed comprise pyridine, piperidine, pipera-zine, morpholine, and alkyl-substituted imidazolines, useful alkanolamines include ethanolamine, diethanolamine, trieth-nolamine and the like.
Various rheological stabilizers in the preferred embodiment of the invention comprise the following reaction products:
I. Monoesters of a dimer acid with polyethylene glycol having a molecular weight range from about 3,000 to about 12,000. This particular monoester is one of the especially preferred partial esters of the present invention;
II. A monoester or a diester of a trimer acid, or mixtures thereof, and polyethylene glycol having a molecular weight range of from about 3,000 to about 12,000;
III. A monoesters, diester, triester, or mixture thereof of an essential 1:1 adduct of dimer acid with maleic acid or maleic anhydride and a polyethylene glycol having a molecular weight range of about 3,000 to about 12,000 and ~'.'~.
133~83~
IV. Ammonium, alkali meal and alkanolamine salts of I, II and III.
The coal-water slurries of the present invention are made from pulverized or powdered coal which has a particle size such about 60% to about 90% will pass through a 200 mesh U.S. standard screen (a 75 micron sieve). Powdered or pulverized coal that may be converted into a water slurry is generally described by Funk in U.S. Patents 4,282,006 and 4,416,666. The mixing of the powdered coal with water to form a slurry is also described by Funk in U.S. patent 4,477,260 at column 21. The rheological additives of the present invention are combined with water and the water in turn is mixed with the coal in a mixer such as Hobart (trademark) mixer or the various art known equivalents thereof.
The coal slurry is made by adding about 0.1% to about 4% and, more preferably, 0 25 to 1 5% by weight, based on total slurry, of the rheological additive as defined here-in to the water used in the coal-water slurry to form a coal-water slurry having anywhere from about 60 to about 80%
solids by weight By used of the rheological additives of the present invention the slurries are liquid at room temper-ature and easily pourable. without the additives, the coal-water slurry is a non-pourable mass that, at room tempera-tures is solid The slurries containing the rheological additives of -lo- 133983~
the present invention should be maintained from about 0~C up to about 95~C preferably from about 2~C to about 75~C and most preferably less than 50~C.
The following Examples are illustrative.
EXAMPLE I
Preparation of C21 dibastic PEG monoester:
~estvaco 1550 (trademark) is a C21 diabasic acid produced at 220-250~C, for 2 hours through the addition of acrylic acid to linoleic acid (AV 272-278; saponification value (SV) 300-308; 88-90~ diabasic acid). For the reaction, 102.6g (0.254 mole) of the acid and 851.2g (0.254 mole) polyethylene glycol having an average molecular weight of 3350 *(Carbowax 3350 were charged to a two-liter four neck round bottom fiask equipped with a subsurface nitrogen inlet tube, therometer, an Dean Stark trap for water of reaction removal. The reactants were heated at 225~C for 19 hours resulting in a drop in acid value of from 18.1 in the starting blend to 9.5 for the resulting partial ester product.
EXAMPLE II
Preparation of Trimer PEG monoester: Empol 1040 Trimer Acid (trademark), a trimerized linoleic acid produced by Emery Chemicals AV 175-192; SV 192-200; 62% tribasic acid, was reacted with polyethylene glycol having an average molecular weight of 3350. For the reaction, 214.5g (0.7072 equivalent) of the trimer acid and 789.7g (0.4714 equivalent) PEG 3350 were charged into a two-liter four-neck round bottom 3~ flask equipped with subsurface nitrogen inlet tube, thermometer, and water trap. The reaction was run at 220~C
*Trade Mark .., .. ... . . . . . . .. . . . .
-11- 133~83~
for 7 hours resulting in a decrease in acid value from 39.5 to 25Ø The resulting partial ester product was a waxy solid melting at about 55~C.
EXAMPLE III
Preparation of Dimer PEG monoester: Dimer acid (AV
189-197; SV 191-199; 77% biastic acid) was reacted with PEG
3350 at a 1:1 molar ratio. For the reaction, 176.7g (0.6142 equivalent) dimer acid and 1028.89 (0.6142 equivalent) of PEG
3350 were charged into a two-liter four-neck round bottom flask equipped with nitrogen inlet tube, thermometer, and water trap. The reaction was run at 200~C for 11 hours resulting in a drop in the acid value of from 28.5 for the starting blend to 15.8 for the resulting disperant product.
The product was found to have a hyroxyl value of 16.2;
viscosity at 210~F of 265.3, refractive index of 1.4632 at 54~C, and SV of 29.9.
EXAMPLE IV
Preparation of Polybasic Acid PEG sesquiester:
21.0g (0.0933 equivalents) of a commercial polybasic acid having an average carboxyl functionality of approximately three obtained from the addition of dimer acid and maleic anydride was reacted with 279.8g (0.0933 equivalents) of polyethylene glycol having an average molecular weight of 6,000. The reactants were charged to a 500ml four-neck round bottom flask equipped with nitrogen inlet tube, thermometer and water trap. The reaction was run at 255~C for 4.5 hours.
3~ The acid value decreased from 17.4 to 8.7.
-12- ~39~3~
1 EXAMpLE V
Preparation of slurries containing rheological additives of Ex. I-IV: 1.75g of disperant of the above examples was dissolved in about 10 grams of water in a Hobart mixins bowl. To the bowl were charge 240.35 grams (175 grams DB) of OxlO0 mesh reclaim Western Pennsylvania coal fines with a moisture content of 26.1%. This coal mixture had the following analysis: Ash 6.92% DB [DB = dry basis]; sulfur 1.149% DB; BTU 14956, moisture and ash free; wet screen analysis, 68.5~200 mesh, 65.8% ~230mesh, 54% ~325 mesh.
The dispersant solution and coal were allowed to mix at low speed (No. 1) for approximately 1 hour. Small water additions were made to account for evaporative losses.
The slurries were transferred to 8 ounce bottles for viscosity determinations using a Brookfield Viscometer LVF with a Helipath stand adaptor and F spindle. Viscosity readings were made over a two inch high volume of the slurry and averaged. The Brookfield viscometer was used to measure a series of conventional viscosities using a number 4 spindle without the Helipath stand. Viscosities are reported in Table I and were obtained on slurries aged approximately 20 hours.
3o TABLE I
DispersantTap Water Slurry Brookfield viscositY (cP) ExamPle (q) % Solids HeliPath 6 rPm Conventional 60 rPm I 14.80 68.8 21,320 700 II 12.58 69.4 53,560 1,100 III 6.49 71.1 43,160 750 IV 5.80 71.3 55,640 1,500 ~39~39 EXA~IPLE VI
Preparation of Polybasic Acid PEG Diester: 39.lg (0.1732 equivalent) of the polybasic acid of Example IV and 932.8g (0.2310 equivalent) polyethylene glycol (avg. mw = 8000), were charged to a two-liter four-neck round bottom flask equipped with nitrogen inlet tube, thermometer, and water trap. The reaction was carried out between 210~C and 230~C
for 39.5 hours resulting in an acid value drop of from 9.7 for the starting blend to 3.5 for the resultant ester product.
The blend of coal (Eastern Kentucky freshly pulverized) was made from two grades of fines such that the final blend contained 80 percent smaller than 200 mesh U.S.
standard sieve. In the blend, 47.32% of a coal 58.43%e 200 mesh was blended with 52.68% of a coal 99.4%~ 200 mesh.
1.75g of the disperant of Example VI was dissolved in 73.25g tap water in a 500 ml stainless steel cup. The disperant was mixed at moderate agitation and 175.0g of the coal blend slowly added. The slurry (70.7% solids) was allowed to mix for an additional 15 minutes after all of the coal had been added resulting in a Brookfield model LVF
Helipath Stand viscosity of 71,700 cP at 6 rpm using F
spindle. No separation of the slurry was observed over 10 weeks storage.
EXAMPLE VII
Evaluation of Additional Rheological Additives in Pulverized Coal Slurries: Utilizing the coal blend of Example VI, slurries were prepared using 1% (based on coal 3~ weight) of the following rheological additives:
A. Tetra propenyl succinic anhyride monoester with PEG 3350 (AV 15.6) -15- ~33983~
B. Dimer acid-maleic anhyride adduct diester with PEG 3350 (AV 7.8) C. Dimer acid-maleic anhyride adduct diester with PEG 1000 (AV 19.8) D. Dimer acid (60%) monoester with PEG 4000 (AV
11.6) E. Dimer acid-maleic anhyride adduct sesquiester with PEG 6000 (AV 8.7) F. C21 dibasic acid monoester with PEG 6000 (AV
8.5) G. Dimer acid (77%) monoester with PEG 6000 (AV
9.6) H. Dimer acid (77%) monoester with PEG 3350 (AV
15.9) For preparation of the slurries, 1.75g dispersant was dissolved in 73.25g tap water in a Hobart mixing bowl.
175.0g anhyride pulverized coal blend was added and mixing completed at speed Number 1 (lowest) in about one hour.
Small additions of water were made to maintain solids level or improve flow when slurries were too viscous.
Viscosities were measured using a Brookfield Helipath Stand with the LVF model viscometer using an F
spindle. Conventional viscosity determinations were also made using the LVF viscometer but with Number 4 spindle.
Slurries were aged about 20 hours prior to viscosity determination. Results are provided in Table II. Percent solids were determined by drying a small amount of the prepared slurry.
3o -16- 133~8~9 l EXAMPLE VIII
Dimer acid reaction products with polyethylene glycols in the molecular weight range of 3350 to 20,000 were prepared using a weight ratio charge of 30~ dimerized linoleic acid and 70~ polyglycol in accordance with procedure of Example 8 of European Patent Application 0131558. These dispersants (6-10), which are polyethylene glycol di(dimerates) containing su~stantial amounts of unreacted dimer acid, were compared with products prepared in accordance with the present invention (1-5) wherein dimer is reacted with the PEG at a 1:1 mole ratio.
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Dispersant Polyether AV of % Dimer AV of No. Glycol M.W. Reactant Charge* In Charge Product 1 3350 28.5 14.7 15.8 2 4500 22.1 '11.4 11.9 3 6000 17.0 8.7 9.1 4 8000 13.1 6.7 7.1 20000 5.4 2.8 3.1 6 3350 ~8.5 30.0 35.5 7 4500 58.5 30.0 41.5 8 6000 58.5 30.0 45.2 9 8000 58.5 30.0 48.7 '0 20000 5~.5 30.0 48.6 *Calculated value when not miscible The dispersants were evaluated by preparing slurries in accordance with the procedure of Example V using beneficiated silt pond coal 88.1~ passing 200 mesh U.S. Standard Sieve 82.7% passing 230 mesh U.S. Standard Sieve 73.8% passing 325 mesh U.S. Standard Sieve Results are reported in Table III.
In a second evaluation, pulverized bituminous coal from Stockton/Lewiston Seam, West Virginia 75% passing 200 mesh U.S. Standard Sieve 70.5% passing 230 mesh U.S. Standard Sieve 61% passing 325 mesh U.S. Standard Sieve was employed for the slurry preparation in accordance with the technique of Example VII and results are reported in Table IV.
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I~ is readily apparent from the data that the rheological additives (dispersants) obtained in accordance with the pre~ent invention gave superior viscosity characteristics, when compared at comparable solids levels, than the composi-tions of European Patent Application 0131558 published January 16, 1985.
EXAMPLE IX
various salts of the partial ester of Example III
(Dimer acid and PEG 3350 monoester) where prepared in situ during slurry preparation, i e., the rheological additive was dissolved in water and the basic material added thereto at room temperature, dropwise, until a pH of 8.5 was reached.
Slurries were then prepared by the addition of Kanawha countY
West virginia Bituminous Coal (74.2% < 200 mesh, 68.1% ~ 230 mesh, 60.1% C 325 mesh; ash 7.14%; sulfur 0.65% DB) in accor-dance with the usual procedure. For the preparation of these slurries, 0.025% xanthan gum, 0.0125% formaldehyde and 0.1%
defoamer were also included. Results obtained for the various salts were as follows:
20 % Salt Based Slurry Viscosity (cp) on % Helipath Conventional coal Based used Solids 6 rpm 60 rpm 1.0 sodium Hydroxide 72.3 4,000 1,500 1.0 Triethylenetriamine 72.6 7,800 550 1.0 Diethanolamine 69.1 4,700 200 1.0 Morpholine 71.6 11,300 1,250 1.0 Ammonium Hydroxide72.4 11,400 1,200 1.0 Diethylenetriamine72.5 9,400 800 ~ 21 -
POLYETHER GYCOL ESTERS OF
POLYCARBOXYLIC ACIDS AS RHEOLOGICAL
ADDITIVES FOR COAL-WATER SLURRIES
This invention relates to a coal-water slurry having a rheological additive which is the reaction product of a polycarboxylic organic acid and a polyether glycol. The ester reaction product is employed in an amount from about 0.1 to about 4~ by weight of the coal-water slurry, the slurry having from about 60 to about 80% by weight of solids, the balance being water.
In recent years a great deal of interest has developed in utilizing coal-water slurries in lieu of oil for electric power generation not only because of the lower cost of coal but also because of its availability.
Coal-water slurries have been produced with solids contents of about 60 to about 75~ which are fluid and handle in about the same way as petroleum fuels. These coal-water slurries may be burned directly without need of dewatering the mixture. The heat generated during combustion is suffi-ciently high so that the water in the slurry does not prevent it from being used to generate power. Naturally, as the solids of the coal-water slurry increase, the fuel value of the slurry also increases. For this reason, slurries having less than about 50 to 55% solids are unsuitable primarily for economic reasons.
One of the difficulties encountered with coal-water slurries at a solid content of about 60% and higher is that the dispersion of coal in water be~omes an immobile mass and when burned it has to be handled in the same manner as lump coal. Handling in this respect includes not only ~33983~
transportation of the coal from the mine source but also the delivery of the coal to a combustion chamber such as the firebox of a steam boiler. Unless coal-water slurries have the same liquidity as oil at these high solids content so that they may be transported by pipeline and injected into a firebox by spraying, the advantage of using a liquid carrier (i.e., water) for the coal is lost. Stated otherwise, the particles of coal in the slurry at these higher solids levels tend to convert the liquid carrier (water) into a plastic mass whereby the advantage of employing a liquid carrier is lost.
The prior art has overcome some of-these diffi-culties by providing additives which may be used in relative-ly small amounts to assure that the coal-water slurry at high solids content is fluid. Examples of these additives are given by Kovacs in U.S. Patent 4,435,306 Sakaria U.S. Patent 4,398,919 and in European Patent Application 0131558.
Coal-fuel oil slurries containing a dispersing agent are also described by Schmolka et al. in U.S. Patent 4,288,232, Naka et al. U.S. Patent 4,251,229 and Shimizu et al. U.S. Patent 4,187,078-The present invention relates to a coal-water slurry having a novel rheological additive comprising the reaction of:
(a) a polycarboxylic organic acid having from about 16 to 60 carbon atoms and form 2 up to 4 carboxyl groups with (b) a polyether glycol having recurring oxyalkylene groups containing up to 4 carbon atoms and having a molecular weight from about 1,000 to about 20,000; the mole 3~ ratio of said polyether glycol to said polycarboxylic acid ranging from about 1:1 to n-1:1 where n is the number of carboxyl groups in the polycarboxylic acid.
The polyether glycol is selected from the group consisting of polyethylene glycol, polypropylene glycol, and poly(ethylene-propylene) glycol and the polycarboxylic acid is selected from the group consisting of dimer acids, trimer acids, adducts of unsaturated monocarboxylic acids or dimer acids with maleic anhydr~de in a molar ratio of about 1:1, adducts of linoleic acid or similar unsaturated monocarboxylic acids with acrylic-type acids in a molar ratio about 1:1 and adducts of olefins having about 12 to about 40 carbon atoms with maleic acid or maleic anhydride in a molar ratio of about 1:1. Polyethylene glycol having a molecular weight from about 3,000 to 12,000 is particularly useful for the preparation of the rheological additives of this in-vention. The acid value of the rheological,additive istypically 25 to 75 percent of the acid value of the polycarboxylic acid/polyether glycol mixture before reaction.
According to another feature of an embodiment of the present invention all or a portion of the remaining carboxyl groups are converted to a salt form. Salts of ammonia and the group IA or IIA metals, especially sodium or potassium are particularly useful for this purpose.
The rheological additive is employed in an amount from about 0.1 percent to about 4 percent and, more pref-erably, from 0.25 to 1.5 percent in slurries containing from about 60 to about 80 percent by weight solids.
The rheological additives of this invention are utilized in coal-water slurries and are obtained by reacting a polycarboxylic organic acid with a polyether glycol to rorm 3~ an ester. The acids have form about 16 to about 60 carbon 133~8~9 atoms, especially from 21 to 54 carbon atoms, and from 2 up to about 4 carboxyl groups. The acids may be either dimer acids, trimer acids, adducts of unsaturated monocarboxylic acids or dimer acids with maleic anhydride in a molar ratio of about 1:1, adducts of linoleic acid and similar unsatura-ted monocarboxylic acids with acrylic-type acids in a molar ratio of about 1:1 or adducts of olefins having about 12 to about 40 carbon atoms with maleic acid or maleic anhydride in a molar ratio of about 1:1.
Dimer acids are known in the art and described by Barret et al. in U.S. Patent 2,793,220 and Myers et al. U.S.
patent 2,955,121. Trimer acids are also known in the art and are described by Barrett et al. in U.S. Patent 3,097,220.
The dimer acid is obtained by oligomerizing an unsaturated 18 carbon atom naturally occurring unsaturated acyclic monocarboxylic fatty acid such as oleic acid, linoleic acid, linolenic acid and the like to obtain a 36 carbon atom dicarboxylic acid whereas the trimer acid is obtained by oligomerizing the foregoing unsaturated monocarboxylic acids to obtain a 54 carbon acid tricarboxylic acid. In both of these reactions, other products are obtained; however, the reaction is conducted in a manner so that the reaction product is principally the dimer acid or the trimer acid.
other unsaturated acyclic monocarboxlyic acids having at least one ethylenically unsaturated position and from about lO to about 22 carbon atoms can also be used to make the polycarboxylic acids of the present invention. These include decenoic, undecenoic, pentadecenoic, hexadecenoic acids and the like. unsaturated acyclic monocarboxylic acids of the above types may be obtained from natural fats and oils such as tall oil, linseed oil, tung oil, soy oil, rapeseed oil, corn oil, fish oil, beef tallow and mixtures thereof.
Dimer acid prepared as described in the foregoing references containing 75~ or more of dimer acid is preferred whereas trimer acid prepared according to the foregoing references having 60% of more of trimer acids is preferred.
Mixtures of dimer acid and trimer acid are also useful and advantageously employed.
Adducts of maleic anhydride (or acid) with unsa~ 9839 ated monocarboxylic acid and dimer acids are known in the art and are described in U.S. Patents 2,902,499 and 2,975,133.
These adducts are prepared by heating maleic anhydride and an 5 unsaturated acid at a temperature from about 100~C to about 300 C until the addition reaction is completed. The molar ratio of the maleic anhydride to unsaturated acid is generally about 1:1.
A 21 carbon atom dicarboxylic acid designated lO Westvaco 1550 (trademark) may be employed as the polycarboxy-lic acid and comprises the addition product of an 18 carbon atom monocarboxylic unsaturated acid and acrylic acid. Equi-valent unsaturated monocarboxylic acid having at least two ethylenically unsaturated positions and from about 10 to 15 about 22 carbon atoms reacted with an acrylic-~ype acid to produce a dicarboxylic acid may also be employed as the polycarboxylic acid. The acrylic-type acids, as referred to herein, include angelic acid, tiglic acid, senecioic acid, crotonic acid, isocrotonic acid, vinylacetic acid, methacry-20 lic acid and the like mixtures thereof. The -6- 1~39~39 polycarboxylic acid can also be an adduct of maleic acid or maleic anhyride with an olefin, where the olefin has from 12 to 40 carbon atoms and one or two unsaturated positions.
Polyether glycols reacted with the above-described polycarboxylic acids to obtain the reaction product of the present invention comprise higher molecular weight poly (lower oxyalkylene) glycols. The molecular weight of the polyether glycol ranges from about l,000 to about 20,000 and, more preferably, from about 3,000 to about 12,000.
They are comprised of recurring oxyalkylene groups containing up to about 4 carbon atoms and preferably from 2 to 3 carbon atoms. Polyethylene glycol having a molecular weight from about 3,000 to about 12,000 is particularly useful for the preparation of the rheological additives of the present invention, however, polypropylene glycol poly(ethylene-propylene) glycols within the above-described molecular weight ranges are also useful.
The various polyether glycols noted herein may have either a broad or a narrow molecular weight distribution so long as the molecular weight, on average, is within the aforementioned ranges. These ranges apply not only to polyether glycols falling within the range, but also to polyether glycol mixtures having an average molecular weight with the aforesaid range. The commercial glycols employed according to the present invention are within the aforemen-tioned molecular weight ranges and the molecular weights thereof are average molecular weights. Some commercial polyethylene glycols that may be employed according to the present invention have average molecular weights of 1000, 3o _7_ ~ 3983~
1 3350~ 8000, and 20000 and are sold under the trademark Carbowax 1000, 3350, 8000 and 20000.
Lower alkoxy poly (lower oxyalkylene) glycols, i.e., wherein one of the terminal hydroxyl groups is "capped"
with an alkyl group having from 1 to about 4 carbon atoms may also be employed. These lower alkoxy poly (lower oxyalkylene) glycols also are within the molecular weight range as defined above for the polyether glycols. The terminal hydroxyl group generally is "capped" with a methyl group, such as methoxpolyethylene glycol.
Mixtures of any of the polyether glycols noted herein may also be used.
Although the polycarboxylic acid and polyether glycol may be reacted to almost completely esterify the acid, in a preferred embodiment, the molar ratio of polyether glycol to polycarboxylic acid is about 1:1 to n-l:l, wherein n is the number of carboxyl groups in the polycarboxylic acid. The polyether glycol and polycarboxylic acid are reacted to form an ester in which the acid value (AV) of the ester is 25 percent to 75 percent of the acid value of the reactant mixture before esterification. Some unreacted carboxyl groups remain in the ester which in some applica-tions improves the performance as rheological additives.
The rheological additives of the present invention are reaction products of the aforementioned polycarboxylic acids and polyether glycols and are produced in accordance with conventional esterification procedures. Some unreacted glycol and acid remains~in the reaction product and are not removed. Polymerization is avoided by the use of the afore-mentioned molar ratios and controlled degree of reaction. By 13~9839 proceeding in this manner, the esters thus produced will haveunreacted carboxylic acid groups.
According to another feature of an embodiment of the present invention, all or a portion of the remaining carboxylic acid groups are converted to a salt form, These salts of the partial ester are also useful as rheological additives. salts of ammonia and the Group IA or Group IIA
Metals of the Periodic Table of the Elements, especially sodium or potassium metals, are particularly useful. The salts may be formed by reacting the partial ester with the hydroxides of the aforementioned metals or with ammonium hydroxide in an amount from about 50% to about 100% of the free carboxylic acid groups of the partial ester, Salts may also be obtained from alkanolamines or heterocyclic nitrogen compounds having up to about 10 carbon atoms and 1 or 2 nitrogen atoms by reacting the partial ester with the alkanolamine or heterocyclic nitrogen compound in a conventional manner, Various heterocyclic nitrogen compounds that may be employed comprise pyridine, piperidine, pipera-zine, morpholine, and alkyl-substituted imidazolines, useful alkanolamines include ethanolamine, diethanolamine, trieth-nolamine and the like.
Various rheological stabilizers in the preferred embodiment of the invention comprise the following reaction products:
I. Monoesters of a dimer acid with polyethylene glycol having a molecular weight range from about 3,000 to about 12,000. This particular monoester is one of the especially preferred partial esters of the present invention;
II. A monoester or a diester of a trimer acid, or mixtures thereof, and polyethylene glycol having a molecular weight range of from about 3,000 to about 12,000;
III. A monoesters, diester, triester, or mixture thereof of an essential 1:1 adduct of dimer acid with maleic acid or maleic anhydride and a polyethylene glycol having a molecular weight range of about 3,000 to about 12,000 and ~'.'~.
133~83~
IV. Ammonium, alkali meal and alkanolamine salts of I, II and III.
The coal-water slurries of the present invention are made from pulverized or powdered coal which has a particle size such about 60% to about 90% will pass through a 200 mesh U.S. standard screen (a 75 micron sieve). Powdered or pulverized coal that may be converted into a water slurry is generally described by Funk in U.S. Patents 4,282,006 and 4,416,666. The mixing of the powdered coal with water to form a slurry is also described by Funk in U.S. patent 4,477,260 at column 21. The rheological additives of the present invention are combined with water and the water in turn is mixed with the coal in a mixer such as Hobart (trademark) mixer or the various art known equivalents thereof.
The coal slurry is made by adding about 0.1% to about 4% and, more preferably, 0 25 to 1 5% by weight, based on total slurry, of the rheological additive as defined here-in to the water used in the coal-water slurry to form a coal-water slurry having anywhere from about 60 to about 80%
solids by weight By used of the rheological additives of the present invention the slurries are liquid at room temper-ature and easily pourable. without the additives, the coal-water slurry is a non-pourable mass that, at room tempera-tures is solid The slurries containing the rheological additives of -lo- 133983~
the present invention should be maintained from about 0~C up to about 95~C preferably from about 2~C to about 75~C and most preferably less than 50~C.
The following Examples are illustrative.
EXAMPLE I
Preparation of C21 dibastic PEG monoester:
~estvaco 1550 (trademark) is a C21 diabasic acid produced at 220-250~C, for 2 hours through the addition of acrylic acid to linoleic acid (AV 272-278; saponification value (SV) 300-308; 88-90~ diabasic acid). For the reaction, 102.6g (0.254 mole) of the acid and 851.2g (0.254 mole) polyethylene glycol having an average molecular weight of 3350 *(Carbowax 3350 were charged to a two-liter four neck round bottom fiask equipped with a subsurface nitrogen inlet tube, therometer, an Dean Stark trap for water of reaction removal. The reactants were heated at 225~C for 19 hours resulting in a drop in acid value of from 18.1 in the starting blend to 9.5 for the resulting partial ester product.
EXAMPLE II
Preparation of Trimer PEG monoester: Empol 1040 Trimer Acid (trademark), a trimerized linoleic acid produced by Emery Chemicals AV 175-192; SV 192-200; 62% tribasic acid, was reacted with polyethylene glycol having an average molecular weight of 3350. For the reaction, 214.5g (0.7072 equivalent) of the trimer acid and 789.7g (0.4714 equivalent) PEG 3350 were charged into a two-liter four-neck round bottom 3~ flask equipped with subsurface nitrogen inlet tube, thermometer, and water trap. The reaction was run at 220~C
*Trade Mark .., .. ... . . . . . . .. . . . .
-11- 133~83~
for 7 hours resulting in a decrease in acid value from 39.5 to 25Ø The resulting partial ester product was a waxy solid melting at about 55~C.
EXAMPLE III
Preparation of Dimer PEG monoester: Dimer acid (AV
189-197; SV 191-199; 77% biastic acid) was reacted with PEG
3350 at a 1:1 molar ratio. For the reaction, 176.7g (0.6142 equivalent) dimer acid and 1028.89 (0.6142 equivalent) of PEG
3350 were charged into a two-liter four-neck round bottom flask equipped with nitrogen inlet tube, thermometer, and water trap. The reaction was run at 200~C for 11 hours resulting in a drop in the acid value of from 28.5 for the starting blend to 15.8 for the resulting disperant product.
The product was found to have a hyroxyl value of 16.2;
viscosity at 210~F of 265.3, refractive index of 1.4632 at 54~C, and SV of 29.9.
EXAMPLE IV
Preparation of Polybasic Acid PEG sesquiester:
21.0g (0.0933 equivalents) of a commercial polybasic acid having an average carboxyl functionality of approximately three obtained from the addition of dimer acid and maleic anydride was reacted with 279.8g (0.0933 equivalents) of polyethylene glycol having an average molecular weight of 6,000. The reactants were charged to a 500ml four-neck round bottom flask equipped with nitrogen inlet tube, thermometer and water trap. The reaction was run at 255~C for 4.5 hours.
3~ The acid value decreased from 17.4 to 8.7.
-12- ~39~3~
1 EXAMpLE V
Preparation of slurries containing rheological additives of Ex. I-IV: 1.75g of disperant of the above examples was dissolved in about 10 grams of water in a Hobart mixins bowl. To the bowl were charge 240.35 grams (175 grams DB) of OxlO0 mesh reclaim Western Pennsylvania coal fines with a moisture content of 26.1%. This coal mixture had the following analysis: Ash 6.92% DB [DB = dry basis]; sulfur 1.149% DB; BTU 14956, moisture and ash free; wet screen analysis, 68.5~200 mesh, 65.8% ~230mesh, 54% ~325 mesh.
The dispersant solution and coal were allowed to mix at low speed (No. 1) for approximately 1 hour. Small water additions were made to account for evaporative losses.
The slurries were transferred to 8 ounce bottles for viscosity determinations using a Brookfield Viscometer LVF with a Helipath stand adaptor and F spindle. Viscosity readings were made over a two inch high volume of the slurry and averaged. The Brookfield viscometer was used to measure a series of conventional viscosities using a number 4 spindle without the Helipath stand. Viscosities are reported in Table I and were obtained on slurries aged approximately 20 hours.
3o TABLE I
DispersantTap Water Slurry Brookfield viscositY (cP) ExamPle (q) % Solids HeliPath 6 rPm Conventional 60 rPm I 14.80 68.8 21,320 700 II 12.58 69.4 53,560 1,100 III 6.49 71.1 43,160 750 IV 5.80 71.3 55,640 1,500 ~39~39 EXA~IPLE VI
Preparation of Polybasic Acid PEG Diester: 39.lg (0.1732 equivalent) of the polybasic acid of Example IV and 932.8g (0.2310 equivalent) polyethylene glycol (avg. mw = 8000), were charged to a two-liter four-neck round bottom flask equipped with nitrogen inlet tube, thermometer, and water trap. The reaction was carried out between 210~C and 230~C
for 39.5 hours resulting in an acid value drop of from 9.7 for the starting blend to 3.5 for the resultant ester product.
The blend of coal (Eastern Kentucky freshly pulverized) was made from two grades of fines such that the final blend contained 80 percent smaller than 200 mesh U.S.
standard sieve. In the blend, 47.32% of a coal 58.43%e 200 mesh was blended with 52.68% of a coal 99.4%~ 200 mesh.
1.75g of the disperant of Example VI was dissolved in 73.25g tap water in a 500 ml stainless steel cup. The disperant was mixed at moderate agitation and 175.0g of the coal blend slowly added. The slurry (70.7% solids) was allowed to mix for an additional 15 minutes after all of the coal had been added resulting in a Brookfield model LVF
Helipath Stand viscosity of 71,700 cP at 6 rpm using F
spindle. No separation of the slurry was observed over 10 weeks storage.
EXAMPLE VII
Evaluation of Additional Rheological Additives in Pulverized Coal Slurries: Utilizing the coal blend of Example VI, slurries were prepared using 1% (based on coal 3~ weight) of the following rheological additives:
A. Tetra propenyl succinic anhyride monoester with PEG 3350 (AV 15.6) -15- ~33983~
B. Dimer acid-maleic anhyride adduct diester with PEG 3350 (AV 7.8) C. Dimer acid-maleic anhyride adduct diester with PEG 1000 (AV 19.8) D. Dimer acid (60%) monoester with PEG 4000 (AV
11.6) E. Dimer acid-maleic anhyride adduct sesquiester with PEG 6000 (AV 8.7) F. C21 dibasic acid monoester with PEG 6000 (AV
8.5) G. Dimer acid (77%) monoester with PEG 6000 (AV
9.6) H. Dimer acid (77%) monoester with PEG 3350 (AV
15.9) For preparation of the slurries, 1.75g dispersant was dissolved in 73.25g tap water in a Hobart mixing bowl.
175.0g anhyride pulverized coal blend was added and mixing completed at speed Number 1 (lowest) in about one hour.
Small additions of water were made to maintain solids level or improve flow when slurries were too viscous.
Viscosities were measured using a Brookfield Helipath Stand with the LVF model viscometer using an F
spindle. Conventional viscosity determinations were also made using the LVF viscometer but with Number 4 spindle.
Slurries were aged about 20 hours prior to viscosity determination. Results are provided in Table II. Percent solids were determined by drying a small amount of the prepared slurry.
3o -16- 133~8~9 l EXAMPLE VIII
Dimer acid reaction products with polyethylene glycols in the molecular weight range of 3350 to 20,000 were prepared using a weight ratio charge of 30~ dimerized linoleic acid and 70~ polyglycol in accordance with procedure of Example 8 of European Patent Application 0131558. These dispersants (6-10), which are polyethylene glycol di(dimerates) containing su~stantial amounts of unreacted dimer acid, were compared with products prepared in accordance with the present invention (1-5) wherein dimer is reacted with the PEG at a 1:1 mole ratio.
3o -17- ~3~1833 ~,oooooooo .oooooooo .,, C ,, U~ ~
~v ., , U
o u ., ~5 ~v s~
. .
, ~
~ oooooooo m ~ o t~ o ~ r ~ o 0~ ~D
H ~ 10 ~ ~ ~1 H a~ ~
~, L~'~-........
o o~
V o ~v o a 133~8.~g Details were as follows:
Dispersant Polyether AV of % Dimer AV of No. Glycol M.W. Reactant Charge* In Charge Product 1 3350 28.5 14.7 15.8 2 4500 22.1 '11.4 11.9 3 6000 17.0 8.7 9.1 4 8000 13.1 6.7 7.1 20000 5.4 2.8 3.1 6 3350 ~8.5 30.0 35.5 7 4500 58.5 30.0 41.5 8 6000 58.5 30.0 45.2 9 8000 58.5 30.0 48.7 '0 20000 5~.5 30.0 48.6 *Calculated value when not miscible The dispersants were evaluated by preparing slurries in accordance with the procedure of Example V using beneficiated silt pond coal 88.1~ passing 200 mesh U.S. Standard Sieve 82.7% passing 230 mesh U.S. Standard Sieve 73.8% passing 325 mesh U.S. Standard Sieve Results are reported in Table III.
In a second evaluation, pulverized bituminous coal from Stockton/Lewiston Seam, West Virginia 75% passing 200 mesh U.S. Standard Sieve 70.5% passing 230 mesh U.S. Standard Sieve 61% passing 325 mesh U.S. Standard Sieve was employed for the slurry preparation in accordance with the technique of Example VII and results are reported in Table IV.
3o I
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oo o~ O ~ ~ ~ ~ ~ t~ r~ t~ t~ o O ~ ~ ~ ~ ~ ~ ~ ~O ~ ~ ~O ~ ~ ~ Vl H ~3 H ~
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Q
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tt ,. ~,, o ~ ~ o - ~ ~ ~ ~ d' ~P ~ ~r ~P ~r ~ ~ ~ ~ * *
O\o~,a,,~ ............. *
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Ul ~--0~ 0 aD~IoOOOOOOOOO
~oooooooooO
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I~ is readily apparent from the data that the rheological additives (dispersants) obtained in accordance with the pre~ent invention gave superior viscosity characteristics, when compared at comparable solids levels, than the composi-tions of European Patent Application 0131558 published January 16, 1985.
EXAMPLE IX
various salts of the partial ester of Example III
(Dimer acid and PEG 3350 monoester) where prepared in situ during slurry preparation, i e., the rheological additive was dissolved in water and the basic material added thereto at room temperature, dropwise, until a pH of 8.5 was reached.
Slurries were then prepared by the addition of Kanawha countY
West virginia Bituminous Coal (74.2% < 200 mesh, 68.1% ~ 230 mesh, 60.1% C 325 mesh; ash 7.14%; sulfur 0.65% DB) in accor-dance with the usual procedure. For the preparation of these slurries, 0.025% xanthan gum, 0.0125% formaldehyde and 0.1%
defoamer were also included. Results obtained for the various salts were as follows:
20 % Salt Based Slurry Viscosity (cp) on % Helipath Conventional coal Based used Solids 6 rpm 60 rpm 1.0 sodium Hydroxide 72.3 4,000 1,500 1.0 Triethylenetriamine 72.6 7,800 550 1.0 Diethanolamine 69.1 4,700 200 1.0 Morpholine 71.6 11,300 1,250 1.0 Ammonium Hydroxide72.4 11,400 1,200 1.0 Diethylenetriamine72.5 9,400 800 ~ 21 -
Claims (13)
1. A coal-water slurry comprising coal, water and a rheological additive, said rheological additive present in an amount of from about 0.1% to about 4% by weight, based on the total weight of said coal-water slurry, said additive comprising the reaction product of a polycarboxylic organic acid having from about 16 to about 60 carbon atoms and from
2 up to 4 carboxyl groups and a polyether glycol having recurring oxyalkylene groups containing up to 4 carbon atoms and a molecular weight of from about 1,000 to about 20,000, the mole ratio of said polyether glycol to said polycarboxylic acid ranging from about 1:1 to n-1:1, where n is the number of carboxyl groups in the polycarboxylic acid; said coal-water slurry characterized by a solid content of about 60% to about 80% by weight, based on the total weight of said coal-water slurry.
2. The coal-water slurry of claim 1, wherein the rheological additive is present in an amount of from about 0.25%
to about 1.5% by weight, based on the total weight of said coal-water slurry.
2. The coal-water slurry of claim 1, wherein the rheological additive is present in an amount of from about 0.25%
to about 1.5% by weight, based on the total weight of said coal-water slurry.
3. The coal-water slurry of claim 2, wherein the coal has a particle size such that about 60 percent to about 90 percent will pass through a 200 mesh U.S. standard sieve.
4. The coal-water slurry of claim 3, wherein the temperature of the slurry is maintained over a range from about 2°C to about 75°C.
5. The coal-water slurry of claim 1, wherein the polyether glycol is selected from the group consisting of polyethylene glycol, polypropylene glycol, and poly(ethylene-propylene) glycol and the polycarboxylic acid is selected from the group consisting of dimer acids, trimer acids, adducts of unsaturated monocarboxylic acids or dimer acids with maleic anhydride in a molar ratio of about 1:1, adducts of linoleic acid or similar unsaturated monocarboxylic acids with acrylic-type acids in a molar ratio of about 1:1; and adducts of olefins having about 12 to about 40 carbon atoms with maleic acid or maleic anhydride in a molar ratio of about 1:1.
6. The coal-water slurry of claim 5, wherein the polyether glycol is a polyethylene glycol having a molecular weight from about 3,000 to about 12,000.
7. The coal-water slurry of claim 6, wherein the acid value of the rheological additive is 25 to 75 percent of the acid value of the polycarboxylic acid/polyether glycol mixture before reaction.
8. The coal-water slurry of claim 7, wherein the rheological additive is a monoester of a dimer acid and polyethylene glycol having a molecular weight from about 3,000 to about 12,000.
9. The coal-water slurry of claim 8, wherein the rheological additive is a monoester or diester of a trimer acid and polyethylene glycol having a molecular weight from about 3,000 to about 12,000.
10. The coal-water slurry of claim 9, wherein the rheological additive is a monoester, diester or triester of an essentially 1:1 adduct of dimer acid with maleic acid or maleic anhydride and a polyethylene glycol having a molecular weight from about 3,000 to about 12,000.
11. The coal-water slurry of claim 1, wherein all or a portion of the unreacted carboxyl groups of the rheological additive are converted to a salt form.
12. The coal-water slurry of claim 11, wherein the salt is a salt of ammonia, a Group IA or Group IIA metal, an alkanolamine, or a heterocyclic nitrogen compound containing up to about 10 carbon atoms and one or two nitrogen atoms.
13. The coal-water slurry of claim 11, wherein the salt is a salt of ammonia, sodium or potassium.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US81909086A | 1986-01-15 | 1986-01-15 | |
| US819,090 | 1986-01-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1339839C true CA1339839C (en) | 1998-04-28 |
Family
ID=25227176
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000524143A Expired - Fee Related CA1339839C (en) | 1986-01-15 | 1986-11-28 | Polyether glycol esters of polycarboxylic acids as rheological additivescoal-water slurries |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1339839C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115873666A (en) * | 2022-12-09 | 2023-03-31 | 赞宇科技集团股份有限公司 | Low solvent amount liquid laundry bead compositions containing C21 diacids and methods of making |
-
1986
- 1986-11-28 CA CA000524143A patent/CA1339839C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115873666A (en) * | 2022-12-09 | 2023-03-31 | 赞宇科技集团股份有限公司 | Low solvent amount liquid laundry bead compositions containing C21 diacids and methods of making |
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