CA2199341C - Method of producing micron sized sulphur granules - Google Patents
Method of producing micron sized sulphur granules Download PDFInfo
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- CA2199341C CA2199341C CA 2199341 CA2199341A CA2199341C CA 2199341 C CA2199341 C CA 2199341C CA 2199341 CA2199341 CA 2199341 CA 2199341 A CA2199341 A CA 2199341A CA 2199341 C CA2199341 C CA 2199341C
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
- B01J2/02—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by dividing the liquid material into drops, e.g. by spraying, and solidifying the drops
- B01J2/06—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by dividing the liquid material into drops, e.g. by spraying, and solidifying the drops in a liquid medium
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/02—Preparation of sulfur; Purification
- C01B17/0237—Converting into particles, e.g. by granulation, milling
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/02—Preparation of sulfur; Purification
- C01B17/10—Finely divided sulfur, e.g. sublimed sulfur, flowers of sulfur
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Abstract
A method of producing micron sized sulphur granules involving the following described steps. Firstly, heating sulphur until the sulphur becomes molten. Secondly, heating water and inducing movement of the heated water at velocity.
Thirdly, injecting an unbroken stream of the molten sulphur under pressures in excess of 500 p.s.i. into the heated water moving at velocity. An explosive dispersion of the molten sulphur into fine sulphur granules occurs, enhanced by shear forces exerted by the movement of the heated water at velocity.
The described method is capable of producing spherical sulphur granules of less than 45 microns. In the preferred ranges, spherical sulphur granules of less than 10 microns can be obtained.
Thirdly, injecting an unbroken stream of the molten sulphur under pressures in excess of 500 p.s.i. into the heated water moving at velocity. An explosive dispersion of the molten sulphur into fine sulphur granules occurs, enhanced by shear forces exerted by the movement of the heated water at velocity.
The described method is capable of producing spherical sulphur granules of less than 45 microns. In the preferred ranges, spherical sulphur granules of less than 10 microns can be obtained.
Description
- n~ss34 1 TITLE OF THE INVENTION:
method of producing micron sized sulphur granules NAMES OF lhv~l. ~S:
Edward Erank Bertram Rodger Blackwood William Chee Kay James Kenneth Laidler FIELD OF TRE lhvhn~l~
The present invention relates to a method of producing sulphur granules and, in particular, sulphur granules that are smaller than 45 microns.
pr~ OF T~E lhv~il~
Sulphur granules used for agricultural purposes are generally less than 45 microns in size, with a mean granule size of approximately 20 microns. Eor specific applications, even smaller granule sizes may be required. For example, pesticides generally require a granule size of less than 10 microns, with a mean granule size of approximately 5 microns.
Sulphur is generally sold commercially in large slabs.
United States Patent 4,364,774 which issued to Elliot in 1982 describes a method of pelletizing the sulphur to make it easier to handle. The method involves pouring an unbroken stream of molten sulphur into a water bath. Granules can be obtained from these slabs or pellets through a grinding process, but this has inherent problems relating to dust control, fire and explosions.
0 2 799 ~4 1 United States Patent 4,043,717 which issued to Riano in 1977 discloses a device for preparing granular sulphur from a stream of molten sulphur. The device has a spray head surrounded by an annular water jacket. Molten sulphur exits the spray head in what is referred to as a "deluge type" spray.
Impingement of the water on the molten sulphur causes the sulphur to form what are described as "irregular granular pellets". This device does not create consistent size granules and produces a relatively small proportion of granules that are less than 45 microns in size.
rAnA~;An Patent 1,151,372 which issued to Leszczynska et ali in 1983 describes a method of granulation of sulphur by solidifying sulphur droplets in a counter-current air stream.
The Leszczynska et ali reference discloses that "92% of the grains produced are within the range of 1-5 mm in size".
~AnA~;An Patent 1,314,671 which issued to Garcia et al in 1993 describes a method of solidifying sulphur into granules by directing jets of water and sulphur at a rotating disk. The sulphur hardens onto the disk and is broken up into granules as a result of the water striking it. The water and sulphur are then spun free of the rotating disk. However, the Garcia et al reference contains a warning that, if the droplets of sulphur are too small, there will be a great deal of fines that will be dragged away by the cooling water and large size separators will be needed to recover such sulphur out of the cooling water.
In summary, the known methods for solidifying sulphur into granules are not capable of consistently producing an output of sulphur granules, the vast majority of which are of a size of less than 45 microns.
SUMMARY OF T~E lhv~~
What is required is a method that is capable of consistently producing an output of sulphur granules, the vast majority of which are of a size of less than 45 microns.
According to the present invention there is provided a method of producing sulphur granules. Firstly, heating sulphur until the sulphur becomes molten. Secondly, heating water and 10 i n~n~; ng v~ L of the heated water at velocity. Thirdly, injecting an unbroken stream of the molten sulphur under pressures in excess of 500 p.s.i. into the heated water moving at velocity. An explosive dispersion of the molten sulphur into fine sulphur granules occurs, ~nhAnr~d by shear forces exerted by the ~ G L of the heated water at velocity.
The method, as described above, c~ in~ high pressure injection of the molten sulphur and heated water moving at velocity to create fine granules. There is a relation~hip between the injection pressure and the particular size; as the injection pressure is increased, the granules size is decreased.
Although b~n~fi~iAl results may be obtained through the use of the method, as described above, the temperature of the sulphur has an effect on the results obtained. It is preferred that the sulphur be heated to a temperature of between 140 degrees and 159 degrees celsius. For the best results, the sulphur should be heated within a narrower temperature range of between 150 degrees and 159 degrees celsius. At these _LdLures the sulphur is molten with a minimum viscosity.
Although ken~fi~;Al results may be obtained through the use of the method, as described above, the temperature of the heated water also has an effect on the results obtained. It is preferred that the water be heated to a t~ Lure of between 65 degrees and 98 degrees celsius. For the best n 2 ~99~4 1 results, the water should be heated within a narrower temperature range of between 94 degrees and 98 degrees celsius.
The higher the t ~LULe of the heated water, the smaller the particle size. It is, therefore, desirable to keep the water as hot as possible without boiling.
Although b~n~fi~iAl results may be obtained through the use of the method, as described above, it is important that the water be maintained at a velocity sllff;~i~nt to prevent agglomeration, thereby maintaining a smaller the particle size.
It is preferred that the heated water be driven in a circular motion with s-lff~ nt angular velocity as to produce a vortex.
~he use of a vortex is a convenient and controllable manner of obtaining a high velocity water Although b~nefi~ results may be obtained through the use of the method, as described above, an agglomeration of the fine granules tends to occur. It is, therefore, preferred that the heated water be conditioned by the addition of a surfactant. The surfactant retards agglomeration of the fine sulphur granules. The best results have been obtained through the use of caLbo~y ~hyl cellulose with a low degree of substitution.
Although beneficial results may be obtained through the use of the method, as described above, oxidation of molten sulphur produces S02 gas. Even more b~n~fi~ effects may, therefore, be obtained when a blanket of inert gas is placed on the surface of the molten sulphur to prevent the formation of S02 gas. Beneficial results have been obtained when the inert gas is nitrogen.
Although b~n~fi~i~l results may be obtained through the use of the method, as described above, the granules produced are of such a small size that recovery can be a problem. It is, therefore, preferred that a cyclone separator being used to recover the fine sulphur granules from the heated water.
~21Q~34 1 BRIEF ~ ON OF THE
These and other features of the invention will become more apparent from the following description in which reference is made to the ~L~ d drawings, wherein:
FIGURE 1 is a schematic diagram of the method of producing sulphur granules according to the t~h; ngs of the present invention.
10FIGURE 2 is an enlarged side elevation view, in section, of a nozzle used in the method illustrated in FIGURE 1.
~T~,~n - ~11 OF THE I~r ~A~ EMBODIMENT
15The preferred method of producing sulphur granules will now be described with reference to FIGURES 1 and 2.
Firstly, heating sulphur in vat 12 until the sulphur becomes molten. Sulphur goes into a molten state above 119 degrees celsius. It is preferable, however, to have the molten sulphur at low viscosity. In order to obtain molten sulphur with the desired low viscosity, is it preferred that the sulphur be heated to between 140 degrees and 159 degrees celsius. When the sulphur is heated to temperatures of less than 140 degrees, the viscosity of the sulphur hinders the production of fine granules. When the sulphur is heated to temperatures of greater than 159 degrees, the extra heating is counterproductive as it results in an increase in the viscosity of the sulphur. Within the preferred temperature range of 140 degrees to 159 degrees celsius there is a narrower optimum temperature range of between 150 degrees and 159 degrees celsius. Within this narrow range the sulphur becomes molten with a minimum viscosity.
35Secondly, heating water in tank 14 and i n~n~; ng the ~ G L of the water at velocity. There is a correlation between the t~ , ~Lure of the water and the size of the O ~ 7 ~ 9 3 4 resulting sulphur granules obtained. As the temperature increases, the granules size decreases. It is important, however, that the water not be brought to boiling. An operable t~ _~L~LuLe ranqe is between 24 degrees and 98 degrees centigrade, with a preferred temperature range being between 65 degree and 98 degrees centigrade. Within the preferred temperature range of 65 degrees to 98 degrees celsius there is a narrower optimum t~ ~LuLé range of between 94 degrees and 98 degrees celsius. This narrower t~ ,_L~ULe range Le~lesellLs the maximum operating t~ a~uLe without bringing the water to a boil. The heated water is conditioned by the addition of a surfactant. The best results have been obtained using caLb~y ~hyl ce~ lose with a low degree of substitution, less than 0.5 and, preferably, between 0.40 and 0.45. The -.VG
of the water at velocity is induced by a stirrer 16. Stirrer 16 drives the heated water in a circular motion with sufficient angular velocity as to produce a vortex. In order to achieve beneficial results, the velocity of the water should be greater than 0.5 meters per second. It has been det~rmined that this is the minimum velocity that the water must be moving in order to induce a feathering out of the sulphur stream. It should be noted, however, that the velocity of the water must increase as the concentration of fine particulate sulphur increases, in order to prevent sulphur from agglomerating. In other words, as higher concentrations of sulphur are contained in the solution, higher velocities must be induced in the water. The motion of the target water is essential, because if the water were stagnant the sulphur would tend to agglomerate. This problem would be further ~Y~r~rhated if the vessel was shallow, as the sulphur would pile up on the bottom of the target vessel and substantial agglomerations would be produced. The use of a vortex has proven to be a convenient and controllable manner of obtaining water - ~G L of sufficient velocity, as a threshold speed well above the minimum must be obtained and maintained to sustain a vortex.
Thirdly, injecting an unbroken stream of the molten ~ 2 ~9 ~4 1 sulphur under pressures in excess of 500 p.s.i. into a periphery of the vortex. B~n~f;~i~l results have been obtained with an injection pressure in the area of 2000 p.s.i. Two pumps 18 and 19 are employed in the process. Pump 18 is a low pressure feed pump which is used to draw molten sulphur from vat 12. Pump 19 is a high pressure pump which is used to force the molten sulphur through a nozzle 20, which is directed at the heated water in tank 14. A pump that utilizes a high pressure hydraulic cylinder is preferred for pump 19, in view of the t~ _L~LuLe of the molten sulphur, the pressures required, and the non-lubricating nature of molten sulphur.
The pump selected must be capable of generating pressures of between 500 to 3000 p.s.i. at t~ - ~LULeS above 119 degrees celsius to as high as 175 degrees celsius. The operating temperatures described, have been found to have an adverse effect on pump life. Although beneficial results start to be obtained at a pressure threshold of 500 p.s.i., there is a correlation between the pressure and the size of granules produced by the method. As the pressure increases the size of the granules is reduced. For this reason, pressures closer to 2000 p.s.i. are preferred. It is important that the nozzle not be a spray nozzle. What is desired is an unbroken stream of molten sulphur. The selection of the nozzle plays an important role in keeping the size of the granules uniform. Referring to FIGURE 2, there is illustrated the preferred form of discharge nozzle 20. Discharge nozzle 20 has a discharge aperture 22 having an inlet portion 23 of a first diameter and an outlet portion 25 of a second smaller diameter. There is a sloped transition zone 28 between inlet portion 23 and outlet portion 25 of discharge aperture 22. Discharge aperture 22 has a circular discharge opening 30 with a sharp edge 32 on the discharge side. Sloped transition zone 28 and sharp edge 32 both contribute to create an unbroken rapidly accelerating stream. Dep~n~;ng upon the source from which the sulphur to be used is obtained, extraneous material may be contained in the sulphur. This extraneous material can block nozzle 20 and disrupt the described method. It is, therefore, rec~ 'ed O ~ 199~4 ~
that the sulphur be filtered through a 100 micron filter prior to use in order to remove any extraneous material that may be present.
When the molten sulphur is injected under pressure into the heated water, an explosive dispersion of the molten sulphur into fine granules occurs. This explosive dispersion is ~nh~n~ by shear forces exerted by the vortex of heated water moving at velocity. The fine granules are feathered out in the heated water and carried away by the vortex. The high t~ ~laLure of the sulphur causes the localized water to form vapour bubbles around the fine granules, keeping them apart with the aid of the surfactant, caLbu~y Lhyl cellulose. The bubbles collapse as the sulphur is cooled by the heated water.
The method results in relatively uniform spherical particles of very fine or micronized sulphur.
t is preferred that vat 12 be blanketed with an nitrogen ~ held. When oxygen in the air comes in contact with the molten sulphur in vat 12, S02 gas is formed. When a nitrogen blanket is placed over the molten sulphur is vat 12, the nitrogen atmosphere prevents the production of S02 gas.
The fine sulphur granules must be removed from the heated water. In order to accomplish this, a two step procedure is followed. First, pump 24 is used to divert the heated water into a cyclone separator 26 where fine sulphur granules and coarser sulphur granules are separated into two processing streams. This ~loduces a first stream of fine sulphur granules and water, and a second stream of coarser sulphur granules and water. Second, the water is removed by filtration followed by evaporation.
The method described results in very fine micronized sulphur granules which are a relatively uniform spherical shape. Using this method sulphur granules of less than 45 microns can be obtained. When the method is run in the preferred ranges spherical sulphur granules of less than 10 microns can be obtained. The coarser sulphur granules separated out by the cyclone separator can either be recycled or used for other purposes.
It will be apparent to one skilled in the art that ';fi~ations may be made to the illustrated~ i t without departing from the spirit and scope of the invention as hereinafter defined in the Claims.
method of producing micron sized sulphur granules NAMES OF lhv~l. ~S:
Edward Erank Bertram Rodger Blackwood William Chee Kay James Kenneth Laidler FIELD OF TRE lhvhn~l~
The present invention relates to a method of producing sulphur granules and, in particular, sulphur granules that are smaller than 45 microns.
pr~ OF T~E lhv~il~
Sulphur granules used for agricultural purposes are generally less than 45 microns in size, with a mean granule size of approximately 20 microns. Eor specific applications, even smaller granule sizes may be required. For example, pesticides generally require a granule size of less than 10 microns, with a mean granule size of approximately 5 microns.
Sulphur is generally sold commercially in large slabs.
United States Patent 4,364,774 which issued to Elliot in 1982 describes a method of pelletizing the sulphur to make it easier to handle. The method involves pouring an unbroken stream of molten sulphur into a water bath. Granules can be obtained from these slabs or pellets through a grinding process, but this has inherent problems relating to dust control, fire and explosions.
0 2 799 ~4 1 United States Patent 4,043,717 which issued to Riano in 1977 discloses a device for preparing granular sulphur from a stream of molten sulphur. The device has a spray head surrounded by an annular water jacket. Molten sulphur exits the spray head in what is referred to as a "deluge type" spray.
Impingement of the water on the molten sulphur causes the sulphur to form what are described as "irregular granular pellets". This device does not create consistent size granules and produces a relatively small proportion of granules that are less than 45 microns in size.
rAnA~;An Patent 1,151,372 which issued to Leszczynska et ali in 1983 describes a method of granulation of sulphur by solidifying sulphur droplets in a counter-current air stream.
The Leszczynska et ali reference discloses that "92% of the grains produced are within the range of 1-5 mm in size".
~AnA~;An Patent 1,314,671 which issued to Garcia et al in 1993 describes a method of solidifying sulphur into granules by directing jets of water and sulphur at a rotating disk. The sulphur hardens onto the disk and is broken up into granules as a result of the water striking it. The water and sulphur are then spun free of the rotating disk. However, the Garcia et al reference contains a warning that, if the droplets of sulphur are too small, there will be a great deal of fines that will be dragged away by the cooling water and large size separators will be needed to recover such sulphur out of the cooling water.
In summary, the known methods for solidifying sulphur into granules are not capable of consistently producing an output of sulphur granules, the vast majority of which are of a size of less than 45 microns.
SUMMARY OF T~E lhv~~
What is required is a method that is capable of consistently producing an output of sulphur granules, the vast majority of which are of a size of less than 45 microns.
According to the present invention there is provided a method of producing sulphur granules. Firstly, heating sulphur until the sulphur becomes molten. Secondly, heating water and 10 i n~n~; ng v~ L of the heated water at velocity. Thirdly, injecting an unbroken stream of the molten sulphur under pressures in excess of 500 p.s.i. into the heated water moving at velocity. An explosive dispersion of the molten sulphur into fine sulphur granules occurs, ~nhAnr~d by shear forces exerted by the ~ G L of the heated water at velocity.
The method, as described above, c~ in~ high pressure injection of the molten sulphur and heated water moving at velocity to create fine granules. There is a relation~hip between the injection pressure and the particular size; as the injection pressure is increased, the granules size is decreased.
Although b~n~fi~iAl results may be obtained through the use of the method, as described above, the temperature of the sulphur has an effect on the results obtained. It is preferred that the sulphur be heated to a temperature of between 140 degrees and 159 degrees celsius. For the best results, the sulphur should be heated within a narrower temperature range of between 150 degrees and 159 degrees celsius. At these _LdLures the sulphur is molten with a minimum viscosity.
Although ken~fi~;Al results may be obtained through the use of the method, as described above, the temperature of the heated water also has an effect on the results obtained. It is preferred that the water be heated to a t~ Lure of between 65 degrees and 98 degrees celsius. For the best n 2 ~99~4 1 results, the water should be heated within a narrower temperature range of between 94 degrees and 98 degrees celsius.
The higher the t ~LULe of the heated water, the smaller the particle size. It is, therefore, desirable to keep the water as hot as possible without boiling.
Although b~n~fi~iAl results may be obtained through the use of the method, as described above, it is important that the water be maintained at a velocity sllff;~i~nt to prevent agglomeration, thereby maintaining a smaller the particle size.
It is preferred that the heated water be driven in a circular motion with s-lff~ nt angular velocity as to produce a vortex.
~he use of a vortex is a convenient and controllable manner of obtaining a high velocity water Although b~nefi~ results may be obtained through the use of the method, as described above, an agglomeration of the fine granules tends to occur. It is, therefore, preferred that the heated water be conditioned by the addition of a surfactant. The surfactant retards agglomeration of the fine sulphur granules. The best results have been obtained through the use of caLbo~y ~hyl cellulose with a low degree of substitution.
Although beneficial results may be obtained through the use of the method, as described above, oxidation of molten sulphur produces S02 gas. Even more b~n~fi~ effects may, therefore, be obtained when a blanket of inert gas is placed on the surface of the molten sulphur to prevent the formation of S02 gas. Beneficial results have been obtained when the inert gas is nitrogen.
Although b~n~fi~i~l results may be obtained through the use of the method, as described above, the granules produced are of such a small size that recovery can be a problem. It is, therefore, preferred that a cyclone separator being used to recover the fine sulphur granules from the heated water.
~21Q~34 1 BRIEF ~ ON OF THE
These and other features of the invention will become more apparent from the following description in which reference is made to the ~L~ d drawings, wherein:
FIGURE 1 is a schematic diagram of the method of producing sulphur granules according to the t~h; ngs of the present invention.
10FIGURE 2 is an enlarged side elevation view, in section, of a nozzle used in the method illustrated in FIGURE 1.
~T~,~n - ~11 OF THE I~r ~A~ EMBODIMENT
15The preferred method of producing sulphur granules will now be described with reference to FIGURES 1 and 2.
Firstly, heating sulphur in vat 12 until the sulphur becomes molten. Sulphur goes into a molten state above 119 degrees celsius. It is preferable, however, to have the molten sulphur at low viscosity. In order to obtain molten sulphur with the desired low viscosity, is it preferred that the sulphur be heated to between 140 degrees and 159 degrees celsius. When the sulphur is heated to temperatures of less than 140 degrees, the viscosity of the sulphur hinders the production of fine granules. When the sulphur is heated to temperatures of greater than 159 degrees, the extra heating is counterproductive as it results in an increase in the viscosity of the sulphur. Within the preferred temperature range of 140 degrees to 159 degrees celsius there is a narrower optimum temperature range of between 150 degrees and 159 degrees celsius. Within this narrow range the sulphur becomes molten with a minimum viscosity.
35Secondly, heating water in tank 14 and i n~n~; ng the ~ G L of the water at velocity. There is a correlation between the t~ , ~Lure of the water and the size of the O ~ 7 ~ 9 3 4 resulting sulphur granules obtained. As the temperature increases, the granules size decreases. It is important, however, that the water not be brought to boiling. An operable t~ _~L~LuLe ranqe is between 24 degrees and 98 degrees centigrade, with a preferred temperature range being between 65 degree and 98 degrees centigrade. Within the preferred temperature range of 65 degrees to 98 degrees celsius there is a narrower optimum t~ ~LuLé range of between 94 degrees and 98 degrees celsius. This narrower t~ ,_L~ULe range Le~lesellLs the maximum operating t~ a~uLe without bringing the water to a boil. The heated water is conditioned by the addition of a surfactant. The best results have been obtained using caLb~y ~hyl ce~ lose with a low degree of substitution, less than 0.5 and, preferably, between 0.40 and 0.45. The -.VG
of the water at velocity is induced by a stirrer 16. Stirrer 16 drives the heated water in a circular motion with sufficient angular velocity as to produce a vortex. In order to achieve beneficial results, the velocity of the water should be greater than 0.5 meters per second. It has been det~rmined that this is the minimum velocity that the water must be moving in order to induce a feathering out of the sulphur stream. It should be noted, however, that the velocity of the water must increase as the concentration of fine particulate sulphur increases, in order to prevent sulphur from agglomerating. In other words, as higher concentrations of sulphur are contained in the solution, higher velocities must be induced in the water. The motion of the target water is essential, because if the water were stagnant the sulphur would tend to agglomerate. This problem would be further ~Y~r~rhated if the vessel was shallow, as the sulphur would pile up on the bottom of the target vessel and substantial agglomerations would be produced. The use of a vortex has proven to be a convenient and controllable manner of obtaining water - ~G L of sufficient velocity, as a threshold speed well above the minimum must be obtained and maintained to sustain a vortex.
Thirdly, injecting an unbroken stream of the molten ~ 2 ~9 ~4 1 sulphur under pressures in excess of 500 p.s.i. into a periphery of the vortex. B~n~f;~i~l results have been obtained with an injection pressure in the area of 2000 p.s.i. Two pumps 18 and 19 are employed in the process. Pump 18 is a low pressure feed pump which is used to draw molten sulphur from vat 12. Pump 19 is a high pressure pump which is used to force the molten sulphur through a nozzle 20, which is directed at the heated water in tank 14. A pump that utilizes a high pressure hydraulic cylinder is preferred for pump 19, in view of the t~ _L~LuLe of the molten sulphur, the pressures required, and the non-lubricating nature of molten sulphur.
The pump selected must be capable of generating pressures of between 500 to 3000 p.s.i. at t~ - ~LULeS above 119 degrees celsius to as high as 175 degrees celsius. The operating temperatures described, have been found to have an adverse effect on pump life. Although beneficial results start to be obtained at a pressure threshold of 500 p.s.i., there is a correlation between the pressure and the size of granules produced by the method. As the pressure increases the size of the granules is reduced. For this reason, pressures closer to 2000 p.s.i. are preferred. It is important that the nozzle not be a spray nozzle. What is desired is an unbroken stream of molten sulphur. The selection of the nozzle plays an important role in keeping the size of the granules uniform. Referring to FIGURE 2, there is illustrated the preferred form of discharge nozzle 20. Discharge nozzle 20 has a discharge aperture 22 having an inlet portion 23 of a first diameter and an outlet portion 25 of a second smaller diameter. There is a sloped transition zone 28 between inlet portion 23 and outlet portion 25 of discharge aperture 22. Discharge aperture 22 has a circular discharge opening 30 with a sharp edge 32 on the discharge side. Sloped transition zone 28 and sharp edge 32 both contribute to create an unbroken rapidly accelerating stream. Dep~n~;ng upon the source from which the sulphur to be used is obtained, extraneous material may be contained in the sulphur. This extraneous material can block nozzle 20 and disrupt the described method. It is, therefore, rec~ 'ed O ~ 199~4 ~
that the sulphur be filtered through a 100 micron filter prior to use in order to remove any extraneous material that may be present.
When the molten sulphur is injected under pressure into the heated water, an explosive dispersion of the molten sulphur into fine granules occurs. This explosive dispersion is ~nh~n~ by shear forces exerted by the vortex of heated water moving at velocity. The fine granules are feathered out in the heated water and carried away by the vortex. The high t~ ~laLure of the sulphur causes the localized water to form vapour bubbles around the fine granules, keeping them apart with the aid of the surfactant, caLbu~y Lhyl cellulose. The bubbles collapse as the sulphur is cooled by the heated water.
The method results in relatively uniform spherical particles of very fine or micronized sulphur.
t is preferred that vat 12 be blanketed with an nitrogen ~ held. When oxygen in the air comes in contact with the molten sulphur in vat 12, S02 gas is formed. When a nitrogen blanket is placed over the molten sulphur is vat 12, the nitrogen atmosphere prevents the production of S02 gas.
The fine sulphur granules must be removed from the heated water. In order to accomplish this, a two step procedure is followed. First, pump 24 is used to divert the heated water into a cyclone separator 26 where fine sulphur granules and coarser sulphur granules are separated into two processing streams. This ~loduces a first stream of fine sulphur granules and water, and a second stream of coarser sulphur granules and water. Second, the water is removed by filtration followed by evaporation.
The method described results in very fine micronized sulphur granules which are a relatively uniform spherical shape. Using this method sulphur granules of less than 45 microns can be obtained. When the method is run in the preferred ranges spherical sulphur granules of less than 10 microns can be obtained. The coarser sulphur granules separated out by the cyclone separator can either be recycled or used for other purposes.
It will be apparent to one skilled in the art that ';fi~ations may be made to the illustrated~ i t without departing from the spirit and scope of the invention as hereinafter defined in the Claims.
Claims (23)
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of producing sulphur granules, comprising the steps of:
firstly, heating sulphur until the sulphur becomes molten;
secondly, tempering water to suit a desired sulphur particle size and inducing movement of the tempered water at velocity; and thirdly, injecting an unbroken stream of the molten sulphur under pressure into the tempered water moving at velocity, such that an explosive dispersion of the molten sulphur into fine sulphur granules occurs, enhanced by shear forces exerted by the movement of the heated water at velocity.
firstly, heating sulphur until the sulphur becomes molten;
secondly, tempering water to suit a desired sulphur particle size and inducing movement of the tempered water at velocity; and thirdly, injecting an unbroken stream of the molten sulphur under pressure into the tempered water moving at velocity, such that an explosive dispersion of the molten sulphur into fine sulphur granules occurs, enhanced by shear forces exerted by the movement of the heated water at velocity.
2. The method as defined in Claim 1, the injection pressure being within a range of 200 p.s.i. and 3000 p.s.i.
3. The method as defined in Claim 2, the injection pressure being in excess of 500 p.s.i..
4. The method of producing sulphur granules as defined in Claim 1, the sulphur being heated to a temperature of between 140 degrees and 159 degrees Celsius.
5. The method of producing sulphur granules as defined in Claim 2, the sulphur being heated to a temperature of between 150 degrees and 159 degrees celsius, such that the sulphur becomes molten with a minimum viscosity.
6. The method of producing sulphur granules as defined in Claim 1, the water being tempered with a temperature range of between 15 degrees and 98 degrees Celsius.
7. The method of producing sulphur granules as defined in Claim 6, the water being heated within a narrower temperature range of between 65 degrees and 98 degrees Celsius.
8. The method of producing sulphur granules as defined in Claim 7, the water being heated within a narrower temperature range of between 94 degrees and 98 degrees Celsius.
9. The method of producing sulphur granules as defined in Claim 1, the heated water being driven in a circular motion with sufficient angular velocity as to produce a vortex.
10. The method of producing sulphur granules as defined in Claim 1, the velocity of the heated water being at least 0.5 meters per second.
11. The method of producing sulphur granules as defined in Claim 1, the heated water being conditioned by the addition of a surfactant, thereby retarding agglomeration of the fine sulphur granules.
12. The method of producing sulphur granules as defined in Claim 7, the surfactant being carboxymethyl cellulose with a degree of substitution of less than 0.5.
13. The method of producing sulphur granules as defined in Claim 1, a blanket of inert gas being placed over the molten sulphur, thereby retarding oxidation of the molten sulphur which produces SO2 gas.
14. The method of producing sulphur granules as defined in Claim 11, the inert gas being nitrogen.
15. The method of producing sulphur granules as defined in Claim 1, a cyclone separator being used to separate fine sulphur granules from coarser sulphur granules.
16. A method of producing sulphur granules, comprising the steps of:
firstly, heating sulphur to a temperature of between 140 degrees and 159 degrees Celsius, such that the sulphur becomes molten;
secondly, heating water to a temperature of between 65 degrees and 98 degrees Celsius and driving the heated water in a circular motion with sufficient angular velocity as to produce a vortex, the heated water being conditioned by the addition of a surfactant;
thirdly, injecting an unbroken stream of the molten sulphur under pressures in excess of 500 p.s.i. into a periphery of the vortex, such that an explosive dispersion of the molten sulphur into fine granules occurs, enhanced by shear forces exerted by the movement of the heated water at velocity, the surfactant serving to prevent agglomeration of the fine sulphur granules.
firstly, heating sulphur to a temperature of between 140 degrees and 159 degrees Celsius, such that the sulphur becomes molten;
secondly, heating water to a temperature of between 65 degrees and 98 degrees Celsius and driving the heated water in a circular motion with sufficient angular velocity as to produce a vortex, the heated water being conditioned by the addition of a surfactant;
thirdly, injecting an unbroken stream of the molten sulphur under pressures in excess of 500 p.s.i. into a periphery of the vortex, such that an explosive dispersion of the molten sulphur into fine granules occurs, enhanced by shear forces exerted by the movement of the heated water at velocity, the surfactant serving to prevent agglomeration of the fine sulphur granules.
17. The method of producing sulphur granules as defined in Claim 16, the sulphur being heated to a temperature of between 150 degrees and 159 degrees Celsius, such that the sulphur becomes molten with a minimum viscosity.
18. The method of producing sulphur granules as defined in Claim 16, the surfactant being carboxymethyl cellulose with a degree of substitution of less than 0.5.
19. The method of producing sulphur granules as defined in Claim 16, a blanket of nitrogen gas being placed over the molten sulphur, thereby retarding oxidation of the molten sulphur which produces SO2 gas.
20. The method of producing sulphur granules as defined in Claim 16, the injection pressure being 2000 p.s.i.
21. The method of producing sulphur granules as defined in Claim 16, the water being heated to a temperature of between 94 degrees and 98 degrees Celsius,
22. A method of producing sulphur granules, comprising the steps of firstly, heating sulphur to a temperature of between 150 degrees and 159 degrees Celsius, such that the sulphur becomes molten with a minimum viscosity;
secondly, heating water to a temperature of between 94 degrees and 98 degrees Celsius and driving the heated water in a circular motion with sufficient angular velocity as to produce a vortex, the heated water being conditioned by the addition of carboxymethyl cellulose with a degree of substitution of less than 0.5;
thirdly, injecting an unbroken stream of the molten sulphur under pressures of approximately 2000 p.s.i. into a periphery of the vortex, such that an explosive dispersion of the molten sulphur into fine granules occurs, enhanced by shear forces exerted by the movement of the heated water at velocity, the carboxymethyl cellulose serving to retard agglomeration of the fine sulphur granules;
fourthly, separating fine sulphur granules from coarser sulphur granules by passing the heated water containing sulphur granules through a cyclone separator; and fifthly, recovering the fines sulphur granules from the heated water through filtration followed by evaporation.
23. A method of producing sulphur granules, comprising the steps of:
firstly, heating sulphur to a temperature of between 150 degrees and 159 degrees Celsius, such that the sulphur becomes molten with a minimum viscosity;
secondly, heating water to a temperature range of between 94 degrees and 98 degrees Celsius and inducing movement of the tempered water at velocity; and thirdly, injecting an unbroken stream of the molten sulphur at pressures in excess of [500 psi] 35 kilograms per centimeter squared into the heated water moving at velocity, such that an explosive dispersion of the molten sulphur into fine sulphur granules occurs, enhanced by shear forces exerted by the movement of the heated water at velocity.
24. The method of producing sulphur granules as defined in Claim 23, the heated water being driven in a circular motion with sufficient angular velocity as to produce a vortex.
25. The method of producing sulphur granules as defined in Claim 23, the velocity of the heated water being at least 0.5 meters per second.
26. The method of producing sulphur granules as defined in Claim 23, the heated water being conditioned by the addition of a surfactant, thereby retarding agglomeration of the fine sulphur granules.
27. The method of producing sulphur granules as defined in Claim 26, the surfactant being carboxymethyl cellulose with a degree of substitution of less than 0.5.
28. The method of producing sulphur granules as defined in Claim 23, a blanket of inert gas being placed over the molten sulphur, thereby retarding oxidation of the molten sulphur which produces SO2 gas.
29. The method of producing sulphur granules as defined in claim 28, the inert gas being nitrogen.
30. The method of producing sulphur granules as defined in Claim 23, a cyclone separator being used to separate fine sulphur granules from coarser sulphur granules.
31. The method of producing sulphur granules as defined in
secondly, heating water to a temperature of between 94 degrees and 98 degrees Celsius and driving the heated water in a circular motion with sufficient angular velocity as to produce a vortex, the heated water being conditioned by the addition of carboxymethyl cellulose with a degree of substitution of less than 0.5;
thirdly, injecting an unbroken stream of the molten sulphur under pressures of approximately 2000 p.s.i. into a periphery of the vortex, such that an explosive dispersion of the molten sulphur into fine granules occurs, enhanced by shear forces exerted by the movement of the heated water at velocity, the carboxymethyl cellulose serving to retard agglomeration of the fine sulphur granules;
fourthly, separating fine sulphur granules from coarser sulphur granules by passing the heated water containing sulphur granules through a cyclone separator; and fifthly, recovering the fines sulphur granules from the heated water through filtration followed by evaporation.
23. A method of producing sulphur granules, comprising the steps of:
firstly, heating sulphur to a temperature of between 150 degrees and 159 degrees Celsius, such that the sulphur becomes molten with a minimum viscosity;
secondly, heating water to a temperature range of between 94 degrees and 98 degrees Celsius and inducing movement of the tempered water at velocity; and thirdly, injecting an unbroken stream of the molten sulphur at pressures in excess of [500 psi] 35 kilograms per centimeter squared into the heated water moving at velocity, such that an explosive dispersion of the molten sulphur into fine sulphur granules occurs, enhanced by shear forces exerted by the movement of the heated water at velocity.
24. The method of producing sulphur granules as defined in Claim 23, the heated water being driven in a circular motion with sufficient angular velocity as to produce a vortex.
25. The method of producing sulphur granules as defined in Claim 23, the velocity of the heated water being at least 0.5 meters per second.
26. The method of producing sulphur granules as defined in Claim 23, the heated water being conditioned by the addition of a surfactant, thereby retarding agglomeration of the fine sulphur granules.
27. The method of producing sulphur granules as defined in Claim 26, the surfactant being carboxymethyl cellulose with a degree of substitution of less than 0.5.
28. The method of producing sulphur granules as defined in Claim 23, a blanket of inert gas being placed over the molten sulphur, thereby retarding oxidation of the molten sulphur which produces SO2 gas.
29. The method of producing sulphur granules as defined in claim 28, the inert gas being nitrogen.
30. The method of producing sulphur granules as defined in Claim 23, a cyclone separator being used to separate fine sulphur granules from coarser sulphur granules.
31. The method of producing sulphur granules as defined in
Claim 23, including the step of recovering fine sulphur granules from the heated water through filtration followed by evaporation.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2199341 CA2199341C (en) | 1997-03-06 | 1997-03-06 | Method of producing micron sized sulphur granules |
| EP98905185A EP0963340B1 (en) | 1997-02-27 | 1998-02-26 | Method of producing micron sized sulphur granules |
| DE69818230T DE69818230T2 (en) | 1997-02-27 | 1998-02-26 | METHOD FOR PRODUCING SULFUR GRANULES IN THE MICROMETER AREA |
| PCT/CA1998/000163 WO1998038126A1 (en) | 1997-02-27 | 1998-02-26 | Method of producing micron sized sulphur granules |
| AU60861/98A AU737554B2 (en) | 1997-02-27 | 1998-02-26 | Method of producing micron sized sulphur granules |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2199341 CA2199341C (en) | 1997-03-06 | 1997-03-06 | Method of producing micron sized sulphur granules |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2199341A1 CA2199341A1 (en) | 1998-09-06 |
| CA2199341C true CA2199341C (en) | 2002-11-26 |
Family
ID=4160117
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2199341 Expired - Lifetime CA2199341C (en) | 1997-02-27 | 1997-03-06 | Method of producing micron sized sulphur granules |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2199341C (en) |
-
1997
- 1997-03-06 CA CA 2199341 patent/CA2199341C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2199341A1 (en) | 1998-09-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDC | Correction of dead application (reinstatement) | ||
| MKEX | Expiry |
Effective date: 20170306 |