CA1091016A - Production of solid fuel-water slurries - Google Patents
Production of solid fuel-water slurriesInfo
- Publication number
- CA1091016A CA1091016A CA280,143A CA280143A CA1091016A CA 1091016 A CA1091016 A CA 1091016A CA 280143 A CA280143 A CA 280143A CA 1091016 A CA1091016 A CA 1091016A
- Authority
- CA
- Canada
- Prior art keywords
- slurry
- solid fuel
- water
- sulfonic acid
- salt
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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- Liquid Carbonaceous Fuels (AREA)
Abstract
PRODUCTION OF SOLID
FUEL-WATER SLURRIES
(D#74,433-F) ABSTRACT
The pumpability of solid fuel-water slurries is improved by incorporation therein of small amounts of ammonia and a surface-active agent.
-I-
FUEL-WATER SLURRIES
(D#74,433-F) ABSTRACT
The pumpability of solid fuel-water slurries is improved by incorporation therein of small amounts of ammonia and a surface-active agent.
-I-
Description
~t~ ti This invention relates to the production of slur-ries of solid fuels in water. More particularly it is con-cerned with the production of slurries of finely-ground solid fuel in water in which the slurries have a hish solids content but still are pumpable.
Most solid fuels, as mined, contain varying amounts of water which in some instances may range up to 40 wt. % or even higher in the case of low grade solid fuels. This water, is an undesirable constituent of the fuel, partic-ularly in the case of fuels of high water content. If the mined solid fuel is to be transported to its place of end use by rail this means the transportation of a large amount of non-combustible material having no fuel value. If the solid fuel is to be transported by pipeline in the form of a slurry here again water trapped in the pores of the solid fuel, which takes no part in the formation of the slurry, mist again be transported. Thus a slurry containing 50 wt.
% water and 50 wt. ~ solid fuel would contain considerably less than that amount of fuel when the fuel is measured on a dry basis.
The amount of water necessary to form a pumpable slurry depends on the surface characteristics of the solid fuel. For example, soot formed during the partial oxidation of a carbonaceous material has such a high surface area that a concentration of such soot in ~ater in excess of a few wt. % renders the resulting slurry u~pumpable. In the case of a slurry which is to be fed to a gas generat~r, it is necessary that the solid fuel be ground to such an extent that a major portion thereof will pass through a 200 mesh sieve so that the particles are small enough to be substantially completely converted to oxides of carbon during their short residence time within the gasification zone.
However, ordinarily before reaching the gasification zone the slurry must pass through various pieces of equipment such as heat exchangers and compressors on its way from the slurry zone to the gas generation zone. Accordingly, the slurry must be pumpable but in the case of a slurry made up of solid fuel particles most of which will pass through a 200 mesh sieve it has been found that ordinarily, a pumpable slurry must contain from about 55 to 60 wt. % water.
Unfortunately a slurry containing this amount of water renders the operation of the gasifier unsatisfactory as this excessive amount of water moderates the temperature of the reaction zone to such an extent that its thermal efficiency is seriously impaired. It has been found that a suitable amount of water in a solid fuel-water slurry which is to be used as feed to a gas generation zone is between about 40 and 50 wt. % preferably between 40 and 45 wt. %.
It is therefore an object of this invention to produce solid fuel water slurries having a relatively high solids content. Another object is to produce solid fuel-water slurries suitable for use as feed to a solid fuel gasification zone. Still another object of the invention is to produce pumpable slurries of solid fuel in water wherein a major portion of the solid fuel will pass through a 200 mesh sieve and in which the water content of the slurry will range between about 40 and 50 wt. %. These and other objects will be obvious to those skilled in the art from the following disclosure.
~,~J'~
According to our invention there is provided a process for the production of a solid fuel-water slurry of improved pumpability characteristics which comprises forming a solid fuel-water slurry containing NH40H in an amount between about 0.1 and 5 wt. % and also containing an anionic surface active agent comprising a salt of an organic sul-fonic acid in an amount between 0.01 and 3.0 wt. %, said amounts being based on the final weight of the slurry.
Any solid fuel such as lig~ite, sub-bituminous coal, bituminous coal, anthracite and coke and mixtures thereof may be used in the process of our invention although our process is more particularly adapted to use with lower grade fuels such as sub-bituminous coal and lignite. The solid fuel should be in finely-divided form so that at least 50 wt. % and preferably at least 80 wt. % passes through a 200 mesh sieve (U.S. standard).
Although it is possible to use gaseous NH3 which combines with the slurry water to form NH40H, it is more convenient to use concentrated ammonium hydroxide. It has also been found that NH40H for our purposes, is superior to other bases such as KOH. The NH40H should be present in the slurry in an amount between about 0.1 and 5.0 wt. %
preferably between 0.2 and 3.0 wt. % based on the final weight of the slurry.
While any surface active agent may be used to some extent in the procecs of our invention, it has been found that anionic surface active asents comprising an alkali metal or alkaline earth metal salt of an organic sulfonic acid is superior, for the purposes of our invention,to otAer types of surface active agents. Examples of ~U'~101 ~i particularly suitable surface active agents are the calcium, sodium and ammonium salts of organic sulfonic acids such as
Most solid fuels, as mined, contain varying amounts of water which in some instances may range up to 40 wt. % or even higher in the case of low grade solid fuels. This water, is an undesirable constituent of the fuel, partic-ularly in the case of fuels of high water content. If the mined solid fuel is to be transported to its place of end use by rail this means the transportation of a large amount of non-combustible material having no fuel value. If the solid fuel is to be transported by pipeline in the form of a slurry here again water trapped in the pores of the solid fuel, which takes no part in the formation of the slurry, mist again be transported. Thus a slurry containing 50 wt.
% water and 50 wt. ~ solid fuel would contain considerably less than that amount of fuel when the fuel is measured on a dry basis.
The amount of water necessary to form a pumpable slurry depends on the surface characteristics of the solid fuel. For example, soot formed during the partial oxidation of a carbonaceous material has such a high surface area that a concentration of such soot in ~ater in excess of a few wt. % renders the resulting slurry u~pumpable. In the case of a slurry which is to be fed to a gas generat~r, it is necessary that the solid fuel be ground to such an extent that a major portion thereof will pass through a 200 mesh sieve so that the particles are small enough to be substantially completely converted to oxides of carbon during their short residence time within the gasification zone.
However, ordinarily before reaching the gasification zone the slurry must pass through various pieces of equipment such as heat exchangers and compressors on its way from the slurry zone to the gas generation zone. Accordingly, the slurry must be pumpable but in the case of a slurry made up of solid fuel particles most of which will pass through a 200 mesh sieve it has been found that ordinarily, a pumpable slurry must contain from about 55 to 60 wt. % water.
Unfortunately a slurry containing this amount of water renders the operation of the gasifier unsatisfactory as this excessive amount of water moderates the temperature of the reaction zone to such an extent that its thermal efficiency is seriously impaired. It has been found that a suitable amount of water in a solid fuel-water slurry which is to be used as feed to a gas generation zone is between about 40 and 50 wt. % preferably between 40 and 45 wt. %.
It is therefore an object of this invention to produce solid fuel water slurries having a relatively high solids content. Another object is to produce solid fuel-water slurries suitable for use as feed to a solid fuel gasification zone. Still another object of the invention is to produce pumpable slurries of solid fuel in water wherein a major portion of the solid fuel will pass through a 200 mesh sieve and in which the water content of the slurry will range between about 40 and 50 wt. %. These and other objects will be obvious to those skilled in the art from the following disclosure.
~,~J'~
According to our invention there is provided a process for the production of a solid fuel-water slurry of improved pumpability characteristics which comprises forming a solid fuel-water slurry containing NH40H in an amount between about 0.1 and 5 wt. % and also containing an anionic surface active agent comprising a salt of an organic sul-fonic acid in an amount between 0.01 and 3.0 wt. %, said amounts being based on the final weight of the slurry.
Any solid fuel such as lig~ite, sub-bituminous coal, bituminous coal, anthracite and coke and mixtures thereof may be used in the process of our invention although our process is more particularly adapted to use with lower grade fuels such as sub-bituminous coal and lignite. The solid fuel should be in finely-divided form so that at least 50 wt. % and preferably at least 80 wt. % passes through a 200 mesh sieve (U.S. standard).
Although it is possible to use gaseous NH3 which combines with the slurry water to form NH40H, it is more convenient to use concentrated ammonium hydroxide. It has also been found that NH40H for our purposes, is superior to other bases such as KOH. The NH40H should be present in the slurry in an amount between about 0.1 and 5.0 wt. %
preferably between 0.2 and 3.0 wt. % based on the final weight of the slurry.
While any surface active agent may be used to some extent in the procecs of our invention, it has been found that anionic surface active asents comprising an alkali metal or alkaline earth metal salt of an organic sulfonic acid is superior, for the purposes of our invention,to otAer types of surface active agents. Examples of ~U'~101 ~i particularly suitable surface active agents are the calcium, sodium and ammonium salts of organic sulfonic acids such as
2,6-dihydroxynaphthalene sulfonic acid and lignin sulfonic acid. In this connection ammonia is considered as an alkali metal. The surface active agent should be present in the slurry in an amount between 0.01 and 3.0 wt. % based on the final weight of the slurry, preferred amounts being between 0.1 and 2.0 wt. %.
The ammonia may be added as a gas in which case it will dissolve in the slurry water or it may be added as ammonium hydroxide solution preferably in concentrated form as 28% NH3 or 58% NH40H. In the following examples, any water added to the slurry is used to calculate the total weight of the slurry. In some instances, solid fuel has also been added to the slurry to keep the percentage of solids constant for true comparison purposes.
The following examples are submitted for illus-trative purposes only and it should not be construed that the invention is restricted thereto. Although in the examples the ammonia and surface active agent are added after formation of the slurry, it will be appreciated that it is their presence in the slurry that results in the viscosity being lower than in their absence. It is therefore within the contemplation of the invention that the slurry may be made with ammoniated water or that the ammonia may be added to the water simultaneously with the solid fuel. Similarly the surface active agent may be added to the water prior to or during the addition of the solid fuel and ammonia to the water.
~.O'~
EX~MPLE I
The coal used in this example was a dried Kentucky coal having the following sieve analysis:
Sieve # Wt. %
0.08 0.08 0.12 100 0.28 lS0 1.92 200 3.56 230 7.28 325 22.20 -325 64.48 A slurry containing 51.9 wt. % of the dry coal in water was prepared and various additives were introduced into separate portions of the slurry. Viscosities were determined on a Stormer viscosimeter and are reported in centipoises, ExperimentaI data appear below.
Additive Wt. % of Total Slurry Viscosity none - 214 A 0.03 194 A 0.13 152 A 0.20 145 A 0.33 108 B 0.33 105 ~.V~31(~.L~j TABLE 2 (cont'd.) Additive Wt. % of Total Slurry Viscosity NH40H 1.93 140 NH40H + A 1.93, 0.03 124 NH40H 0.97 155 NH40H + A 0.97, 0.03 115 NH40H + A 0.97, 0.07 105 KOH 1.93 214 KOH + A 1.93, 0.03 195 NH40H + B 0.97, 0.33 96 A = sodium lignin sulfonate B = sodium salt of 2,6- dihydroxynaphthalene sulfonic acid EXAMPLE II
In this example the same coal used in Example I
was formed into a coal-water slurry containing 49.1 wt. %
solids measured on a dry basis. The viscosity of the s~urry and those of the slurry with various additives are shown below.
Additive Wt. ~ of Total SlurryViscosity none - 144 NH40H 0.23 114 NH40H + C 0.23, 0.10 99 C 0.10 106 C = ammonium lignin sulfonate The foregoing data show that NH40H is unexpectedly superior to KOH in reducing the viscosity of the slurry and also shows the superior results obtained by the combination of NH40H and the surface active agent. By the use of these additives it is possible to increase the solids content of the solid fuel-water slurry and still retain pumpability.
l.U~31~
EXAMPLE III
In this example the solid fuel is Kentucky bitumin-ous coal having the following sieve analysis:
U. S. Standard Sieve Wt. % Retained o 100 0.16 150 3.32 200 10.0 230 11.12 325 40.36 400 15.56 -40Q 19.48 The Stormer viscosities of water slurries of various compositons are reported below:
Wt.% Dry Solids Additive Wt.% of Slurry Viscosity 55.06KOH 0.2 683 55.14KOH, C 0.6, 0.1 695 52.8 - ~ 490 52.8 KOH 0.2 478 52.8KOH, C 0.2, 0.1 510 52.8 A 0.2 427 52.8KOH, A 0.2, 0.2 486 A = sodium lignin sulfonate C = ammonium lignin sulfonate ~i V'31(J ~i These data in the foregoing examples show that, as might be expected, the addition of a surface active agent lowers the viscosity of the slurry but it was not to be expected that the addition of ammonia to the slurry contain-ing the surface active agent would result in a further reduction in the viscosity. They also show that KOH unlike ammonia, has the opposite effect in that when KOH is added to a slurry containing a surface active agent, there is an increase in the viscosity.
EXAMPLE IV
In this example, the same coal was used as in Example I. The Stormer viscosities of water slurries of various compositions are tabulated below:
Wt.% Dry Solids Additive Wt.% of Slurry Viscosity 51.9 214 51.9 ( 4)2 1.83 220 51.9 (NH4)2C03 2.0 234 51.9 NH40H 1.93 140 It will be noted that the addition of NH40H
resulted in a decrease in the viscosity of the slurry and that the addition of tNH4)2S or (NH4)2 C03 resulted in an increase in the viscosity of the slurry.
The foregoing data show that NH40H is unexpectedly superior to KOH in reducing the viscosity of the slurry and also shows the superior results obtained by the combination of NH40H and the surface active agent. By the use of these additives it is possible to increase the solids content of the solid fuel-water slurry and still retain pumpability.
l.U~Jl~
Various modifications of the invention as herein-before set forth may be made without departing from the spirit and scope thereof, and therefore, only such limi-tations should be made as are indicated in the appended claims.
The ammonia may be added as a gas in which case it will dissolve in the slurry water or it may be added as ammonium hydroxide solution preferably in concentrated form as 28% NH3 or 58% NH40H. In the following examples, any water added to the slurry is used to calculate the total weight of the slurry. In some instances, solid fuel has also been added to the slurry to keep the percentage of solids constant for true comparison purposes.
The following examples are submitted for illus-trative purposes only and it should not be construed that the invention is restricted thereto. Although in the examples the ammonia and surface active agent are added after formation of the slurry, it will be appreciated that it is their presence in the slurry that results in the viscosity being lower than in their absence. It is therefore within the contemplation of the invention that the slurry may be made with ammoniated water or that the ammonia may be added to the water simultaneously with the solid fuel. Similarly the surface active agent may be added to the water prior to or during the addition of the solid fuel and ammonia to the water.
~.O'~
EX~MPLE I
The coal used in this example was a dried Kentucky coal having the following sieve analysis:
Sieve # Wt. %
0.08 0.08 0.12 100 0.28 lS0 1.92 200 3.56 230 7.28 325 22.20 -325 64.48 A slurry containing 51.9 wt. % of the dry coal in water was prepared and various additives were introduced into separate portions of the slurry. Viscosities were determined on a Stormer viscosimeter and are reported in centipoises, ExperimentaI data appear below.
Additive Wt. % of Total Slurry Viscosity none - 214 A 0.03 194 A 0.13 152 A 0.20 145 A 0.33 108 B 0.33 105 ~.V~31(~.L~j TABLE 2 (cont'd.) Additive Wt. % of Total Slurry Viscosity NH40H 1.93 140 NH40H + A 1.93, 0.03 124 NH40H 0.97 155 NH40H + A 0.97, 0.03 115 NH40H + A 0.97, 0.07 105 KOH 1.93 214 KOH + A 1.93, 0.03 195 NH40H + B 0.97, 0.33 96 A = sodium lignin sulfonate B = sodium salt of 2,6- dihydroxynaphthalene sulfonic acid EXAMPLE II
In this example the same coal used in Example I
was formed into a coal-water slurry containing 49.1 wt. %
solids measured on a dry basis. The viscosity of the s~urry and those of the slurry with various additives are shown below.
Additive Wt. ~ of Total SlurryViscosity none - 144 NH40H 0.23 114 NH40H + C 0.23, 0.10 99 C 0.10 106 C = ammonium lignin sulfonate The foregoing data show that NH40H is unexpectedly superior to KOH in reducing the viscosity of the slurry and also shows the superior results obtained by the combination of NH40H and the surface active agent. By the use of these additives it is possible to increase the solids content of the solid fuel-water slurry and still retain pumpability.
l.U~31~
EXAMPLE III
In this example the solid fuel is Kentucky bitumin-ous coal having the following sieve analysis:
U. S. Standard Sieve Wt. % Retained o 100 0.16 150 3.32 200 10.0 230 11.12 325 40.36 400 15.56 -40Q 19.48 The Stormer viscosities of water slurries of various compositons are reported below:
Wt.% Dry Solids Additive Wt.% of Slurry Viscosity 55.06KOH 0.2 683 55.14KOH, C 0.6, 0.1 695 52.8 - ~ 490 52.8 KOH 0.2 478 52.8KOH, C 0.2, 0.1 510 52.8 A 0.2 427 52.8KOH, A 0.2, 0.2 486 A = sodium lignin sulfonate C = ammonium lignin sulfonate ~i V'31(J ~i These data in the foregoing examples show that, as might be expected, the addition of a surface active agent lowers the viscosity of the slurry but it was not to be expected that the addition of ammonia to the slurry contain-ing the surface active agent would result in a further reduction in the viscosity. They also show that KOH unlike ammonia, has the opposite effect in that when KOH is added to a slurry containing a surface active agent, there is an increase in the viscosity.
EXAMPLE IV
In this example, the same coal was used as in Example I. The Stormer viscosities of water slurries of various compositions are tabulated below:
Wt.% Dry Solids Additive Wt.% of Slurry Viscosity 51.9 214 51.9 ( 4)2 1.83 220 51.9 (NH4)2C03 2.0 234 51.9 NH40H 1.93 140 It will be noted that the addition of NH40H
resulted in a decrease in the viscosity of the slurry and that the addition of tNH4)2S or (NH4)2 C03 resulted in an increase in the viscosity of the slurry.
The foregoing data show that NH40H is unexpectedly superior to KOH in reducing the viscosity of the slurry and also shows the superior results obtained by the combination of NH40H and the surface active agent. By the use of these additives it is possible to increase the solids content of the solid fuel-water slurry and still retain pumpability.
l.U~Jl~
Various modifications of the invention as herein-before set forth may be made without departing from the spirit and scope thereof, and therefore, only such limi-tations should be made as are indicated in the appended claims.
Claims (12)
1. A process for improving the pumpability of a high solids content water slurry of a solid fuel selected from the group consisting of sub-bituminous coal and lignite which comprises forming a water slurry of said solid fuel containing at least 50% solids by weight, said slurry also containing NH40H in an amount between 0.1 and 5.0 weight percent and also containing an anionic surface-active agent comprising a salt of an organic sulfonic acid in an amount between 0.01 and 3.0 weight percent, said amounts being based on the final weight of the slurry.
2. The process of Claim 1 in which the solid fuel is lignite.
3. The process of Claim 1 in which the solid fuel is sub-bituminous coal.
4. The process of Claim 1 in which at least 50 wt. percent of the solid fuel passes through a 200 mesh sieve.
5. The process of Claim 1 in which at least 80 wt. percent of the solid fuel passes through a 200 mesh sieve.
6. The process of Claim 1 in which the organic sulfonic agent is 2,6-dihydroxynaphthalene sulfonic acid.
7. The process of Claim 1 in which the organic acid is lignin sulfonic acid.
8. The process of Claim 1 in which the salt of the organic sulfonic acid is a calcium salt.
9. The process of Claim 1 in which the salt of the organic sulfonic acid is sodium.
10. The process of Claim 1 in which the salt of the organic sulfonic acid is ammonium.
11. The process of Claim 1 in which the slurry contains between about 40 and 50 wt. % in water.
12. The process of Claim 11 in which the slurry contains between about 40 and 45 wt. % water.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US69941076A | 1976-06-24 | 1976-06-24 | |
| US699,410 | 1976-06-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1091016A true CA1091016A (en) | 1980-12-09 |
Family
ID=24809190
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA280,143A Expired CA1091016A (en) | 1976-06-24 | 1977-06-08 | Production of solid fuel-water slurries |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1091016A (en) |
-
1977
- 1977-06-08 CA CA280,143A patent/CA1091016A/en not_active Expired
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |