US3582147A - Sulfur transportation in pipelines - Google Patents

Abstract

An improved method of transporting sulfur-liquid hydrocarbon slurries through pipelines without causing sulfur agglomeration, sticking, deposition or plugging of the pipelines. The invention relates to an improved and novel process of preventing sulfur agglomeration, sticking, deposition and plugging of pipelines transporting sulfur in the form of a sulfur-liquid hydrocarbon slurry.

Description

C United States Patent [72] lnventor Ronald K. June 56] References Cited 1 23 UNITED STATES PATENTS 121] P 2.798,772 7/1957 Redcay 302/14- [22] Filed Dec. 18,1968

3,368,876 2/1968 Bailey, Jr 302/14 [45] Patented M971 3 443 837 5/1969 M 1 1 302 14 [73] Assign she Oil Company eyere a New York, N.Y. Primary Examiner-Andres H. Nielsen Attorneys-George G. Pritzker and J. H, McCarthy ABSTRACT: An improved method of transporting sulfurliquid hydrocarbon slurries through pipelines without causing [54] SUUTUR TRANSPPRTATION [N PIPELINES sulfur agglomeration, sticking, deposition or plugging of the 5 Claims, No Drawings pipelines [52] U.S. Cl 302/66, The invention relates to an improved and novel process of 302/14 preventing sulfur agglomeration, sticking, deposition and [51] Int. Cl 865g 53/30 plugging of pipelines transporting sulfur in the form of a sul- [50] Field oi Search 302/ 14, 16 fur-liquid hydrocarbon slurry.

SULFUR TRANSPORTATION IN PIPELINES BACKGROUND OF THE INVENTION The transportation of sulfur neat or as a water or oil slurry in pipelines is well known in the art as noted by reference to U.S. Pats. Nos. 2,798,772; 2,917,345 or 2,947,578 or as described in Pipeline Industry, June, 1967, pages 5860. In making the sulfur into a sulfur-hydrocarbon slurry, the sulfur is generally sprayed in molten form into either water or a hydrocarbon to form a slurry suitable for transportation through a pipeline. Formation of a stable slurry wherein the sulfur does not undergo any undesirable change or the slurry does not exhibit a tendency to wide variation in viscosity is essential to the process in addition to other problems which may be encountered during and after transportation of the slurry through a pipeline. Thus, agglomeration and separation of the sulfur from the carrier fluid, plating, depositing or coating of the sulfur on pipeline walls causing plugging of the pipeline, corrosion, particle attrition and viscosity changes due to pressure and temperature variations requiring greater pumping power which increases operation costs, etc., are only a few of the problems normally encountered in transporting sulfurliquid hydrocarbon slurries through pipelines.

Although the'above are serious problems for consideration in transporting sulfur through pipelines, nevertheless the transportation of sulfur in slurry form through pipelines can be made to be an effective, attractive and economic means of sulfur transportation, particularly since sulfur is recovered or ob tained from isolated, remote and inaccessible areas, and must be transported to desired accessible areas. As noted above, a number of methods have been proposed for pipeline transportation of sulfur slurries such as injecting molten sulfur into water or a liquid hydrocarbon thereby forming a sulfur slurry for pipeline transportation. These methods for making sulfur slurries suitable for transporting through pipelines generally do not overcome the agglomeration, attrition, deposition, sticking, coating and/or plugging problems described above.

An object of the present invention is to transport sulfur as a sulfur-liquid hydrocarbon slurry through pipelines which is stable and flowable.

Still another object of the present invention is to transport through a pipeline sulfur-liquid hydrocarbon slurries without causing sulfur agglomeration, coating, deposition or plugging of the pipeline.

Still another object of this invention is to form a slurry of sulfur in a liquid hydrocarbon medium, which when formed is stable, does not tend to cause sticking, agglomeration or plugging of equipment during the making of the slurry or on storage or pipeline plugging or cause any difficulty in circulation of the slurry when said slurry is pumped and transported through a pipeline and from which the sulfur can be readily recovered at the terrninal end of the pipeline as essentially pure sulfur.

Another object is to transport sulfur as a liquid hydrocarbon slurry by pipeline over great distances under conditions of reduced pumping and handling costs.

Other objects will be apparent from the following description.

SUMMARY OF THE INVENTION The present invention is directed to an improved, novel and new technique for making a sulfur-liquid petroleum slurry and transporting a slurry of a sulfur-liquid petroleum through pipelines over great distances without causing sulfur agglomeration or sticking during the slurry preparation or on its subsequent storage, if necessary, or when pipeline transport ing the slurry so that sulfur deposition on the walls of the pipelines due to the tendency of sulfur under such conditions to adhere to the pipeline walls because of temperature, pressure and other variable conditions so as to plug said lines; by admixing or adding or injecting prior to or after injection into the pipeline ofa slurry of sulfur and a liquid petroleum, a small amount of from 0.01 to percent, preferably between about 0.5 percent to about 5 percent, of an asphaltenic material derived or obtained or present in crude oil and preferably an unrefined crude oil. The asphaltenic material can be added to the slurry of sulfur and liquid petroleum prior to or during the making of the slurry or the asphaltenic material can be injected when necessary in various places along the pipeline where indications are that the slurry might cause sulfur agglomeration, deposition, sticking or plugging of the line. Any plugging detection means known in the art can be used for this purpose. It has been noted that by adding or injecting into a slurry of the sulfur and liquid petroleum in which the sulfur content of the slurry can vary from about 10 percent by weight to about 75 percent by weight or higher, preferably between 30 percent by weight and percent by weight, sulfur, e.g., kerosene or oil distillates or condensates or crude oil during or after the slurry preparation from about 0.0l to 10 percent of an asphaltenic material, that not only does its presence prevent plugging of pipelines transporting said slurry but also preventing agglomeration, sticking and deposition of sulfur on the walls of the pipelines and improves flow of the slurry and reduces pumping costs.

The sulfur-liquid petroleum slurry can by any suitable means such as described in U.S. Pat. No. 2,798,772 or by the method described in copending U.S. Pat. application Ser. No. 663,755, filed Aug. 28, 1967 which matured as U.S. Pat No. 3,443,837. It is preferred that in the making the sulfur-liquid petroleum fraction slurry that the sulfur is produced in spherical form since sulfur in this form in the slurry is more stable and is resistant to agglomeration, separation, attrition and friction.

The phase transfer method for making the sulfur slurry as described in the above-mentioned copending application comprises first forming a sulfur-aqueous liquid (water) slurry and thereafter phase transferring the sulfur particles from the aqueous liquid into a liquid hydrocarbon. Thereafter, the crude oil can be added as desired.

The liquid petroleum carrier for the sulfur can be one ranging in viscosity from a light petroleum fraction such as liquefied petroleum gas (LPG), gasoline, kerosene, fuel oil, lube oil, petroleum distillates, condensates, crude oil and mixtures thereof. Preferred are liquid petroleum containing at least 10 percent or higher of aromatics, preferably about 15- 30 percent aromatic enriched kerosene or oil condensate fractions or crude oil containing 15-80 percent aromatics which include monoand polyaromatic hydrocarbons.

The asphaltenic additive can be obtained from unrefined or refined crude oil and fractions thereof. By unrefined crude oil is meant any crude oil which has not been processed in a refinery. Thus, a crude oil may be used as it is removed from the ground, or it may be first processed in field units such as oil-water separators, degasers, etc. Although just how the asphaltenes function in the slurry mixture is not understood, it has been found that the asphaltenes prevent sulfur agglomeration, sticking and aid in the formation of spherical sulfur particles having dimensions of from 1 to 800 microns and preferably between 20 and 400 microns.

The asphaltenes can be recovered from petroleum stocks by any suitable means such as described in the Journal of the Institute of Petroleum, Feb. 1968, pages S053 and Apr. 1968, pages 107-1 14 or as described in U.S. Pats. No. 3,206,388; 3,228,870; 3,153,623; 2,729,589; 3,368,876; 3,364,138; 3,206,388 and 3,275,076. The latter two patents base materials can be used per se as the asphaltene additive and carrier for the slurry. In other words high asphaltenic crudes or fractions thereof containing at least 1 percent asphaltenes can be used both as the carrier and additive for the sulfur slurry. The asphaltenes, asphaltogenic acids and carboids and their method of recovery and separation from crudes and fractions thereof is also fully described in chapter 9 of the Sachanens book on The Chemical Constituents of Petroleum" and includes petroleum resins, asphaltenes, asphaltogenic acids and their derivatives. Also, the asphaltenic materials described in U.S. Pat. No. 3,275,076; 3,284,340 or 3,336,146 can be used and they can be separated from petroleum by methods described in U.S. Pats. No. 3,364,138 and 3,368,876.

During the preparation of the slurry as the molten sulfur is dispersed into liquid petroleum containing active asphaltenic components to aid in the making of spherical sulfur particles as well as prevent agglomeration, sticking and the like, the slurry can be cooled effectively by vapor cooling such as described in U.S. Pat. No. 2,632,691 or by use of volatile organic materials such as low molecular weight hydrocarbons or chlorinated hydrocarbons in which case the process should be carried out under pressures as described in U.S. Pat. No. 2,316,673.

At the terminal end of the line the sulfur can be readily separated from the slurry by any suitable means.

desirable since spherical sulfur particles in slurries as defined provide optimum pipeline performance such as low pressure drops during its transportation and ease of recovery and pu rification at the terminal end of the pipeline.

The following examples illustrate the essence of the present invention.

A. Molten sulfur at 120- 180 C. was sprayed into aromatic (17 percent) enriched kerosene through a spray nozzle at about 200 psi. pressure drop to give a homogeneous slurry with sulfur solids content of about 16 percent volume in which the sulfur particles were essentially large angular-crystalline particles which began to stick together and agglomerate into a sticky mass within about lOl5 minutes.

TABLE 1B.--EFFECT OF ADDITIVES ON SULFUR DISPERSION INTO PETROLEUM FRACTIONS [Conditions: 500 ml. carrier in 1-liter Morton flask. 90 ml. sulfur at approximately 140 C. added in 0.5-minute. 1,200 r.p.m. with crescent blade stirrer, except as noted] Coagulum (+12 Wt., mesh), median Particle Initial Level, percent particle sphericity temp percent wt. basis size, percent, Carrier wt Type S is (1 1.1. wt.

Experiment:

1 Petroleum traction (Waterton condensate) 22 None 19.1 680 4 2 .110 b L 1 Bry on 430( alkylarylsulfonate). 20. 4 710 5 24 1 Oleic acid-. 30 770 1 21 1 50% dodecyltrimethyl ammonium 13.8 700 15 chloride. '22 1 Dodecylamine 8. 630 21 22 1 Asphaltenes N11 600 57 23 0.1 ..do 4.9 700 54 23 0. 1 6 API crude percent wt. 7. 0 690 39 asphaltenes). 24 1 Crude oil deasphalted residue resins. 6. 3 680 55 25 1 Crude oil deasphalted residue 20. 3 680 0 aromatics. 11......... Hexane 22 0.1 Asphaltenes 8.0 730 43 12 Fresh Medicine River crude oil d 60 None 1.4 315 91 13 Deasphalted Medicine River crud 60 None (3.9% asphaltenes removed) 5. 7 400 12 14 White oil (Viscosity 25 C., 172 cs.) 60 5 2.9 API crude oil (17 percent wt. Nil 135 B5 asphaltenes) n Portion of 30, +50 mesh sulfur particle fraction which rolls down an inclined phase (s1ope=1 in 12).

b Derived from Canadian oil field. AP1gravity=54.9; viscosity, cs. 59 F. =0.95 and 77 77 F.=6.9; B.S. and W. percent vo1.=0.6; flash point, tag open cup, F.=32; pour point, F.=70.

FIA, percent vol. saturates=82 and aromatics=18.

6 API gravity=35.6; viscosity, cs. 59 F.=9.1 and d 600 r.p.m. agitator speed used in all 60 C. runs.

' PREFERRED EMBODIMENT OF THE INVENTION (l) A 40-60 percent sulfur-aromatic 17 percent) enriched kerosene slurry was prepared by phase transfer by first injecting molten sulfur into an aqueous liquid such as water and thereafter contacting the slurry thus formed with the aromatic enriched kerosene to effect phase transfer of the sulfur parti cles into the aromatic enriched kerosene. To the sulfurkerosene slurry was added from about 1 percent to about 2 percent of asphaltenes and thereafter this slurry was injected into a pipeline for transportation to a terminal station. Sulfurkerosene slurries containing a small amount of crude oil thus formed do not fonn agglomerates or did they plug the pipeline. lnstead of using the phase transfer technique for making the slurry, molten sulfur can be injected into the kerosene directly and thereafter admixed with a small amount (l2 percent) asphaltenes.

(II) An advantage of the present process for transporting through pipelines sulfur-liquid petroleum slurries as defined is that the slurry can be also prepared by direction injection of molten sulfur into a suitable petroleum fraction such as kerosene, fuel oil, oil condensate or distillate crude oil and mixtures thereof to which has been added a small amount of asphaltenes so as to aid in making spherical sulfur particles and prevent sulfur agglomeration, deposition and plugging of pipelines. Either process as well as other processes can be used to make the sulfur-liquid petroleum fraction slurry depending on the availability of the carrier. Thus, where water is available the first process can be used and if not the second one can be used.

The presence of a small amount of an asphaltenic material during the preparation of the slurry by method (1) or (ll) has an additional advantage in that an asphaltenic material aids in the formation of spherical sulfur particles which are most F.=0.87; flash point, tag open cup F.=7; pour point F. e

B. The method of (A) was repeated except that 1 percent of asphaltenes was added to the kerosene carrier. The particles formed were microspherical (l0450 microns) in shape and no tendency of the particles to stick or agglomerate were observed for over 24 hours.

In another test different petroleum fractions were used to form sulfur slurries wherein a -ml. portion of molten sulfur at C. was injected as a continuous stream for 0.5 minute into a well-stirred 500 ml. charge of a petroleum carrier. As shown in Table 1 some of the carriers were used neat and to some were added crude oils or crude oil residue products. For comparison various surfactants were also tested as additives to the carriers as shown in Table 1.

From Table 1 it can be seen that only the carriers containing the asphaltenes added as such, or that are indigenous to heavy crude oils, perfonned satisfactorily. That is, with asphaltenes predispersed in the carriers, high degrees of sulfur particle sphericity were attained and at the same time agglomeration losses of sulfur particles to coagulum were suppressed.

Sulfur slurries of the present invention containing small amounts of asphaltenic additives can be transported through pipelines over great distances without the danger of sulfur deposition, agglomeration, sticking or plugging of the pipelines.

At the terminal end of the line the sulfur can be removed from the liquid hydrocarbon by suitable means such as described in U.S. Pat. No. 2,798,772 and the sulfur purified by methods as described in U.S. Pat. No. 2,809,885 or as described in the copending U.S. Pat. application Ser. No. 684,507, filed Nov. 20, 1967 which matured as U.S. Pat. No. 3,489,677 which comprises treating oil contaminated sulfur with an aqueous solution containing a mixture of alkali hydrosulfide and corresponding hydroxide, e.g., ammonium hydrosulfide and ammonium hydroxide or by other suitable means such as sulfur can be recovered from the oil slurry by centrifugation or filtration of particulate sulfur, melting the particles and liquid-liquid extraction with a hydrocarbon solvent containing l0-50 percent aromatics. Thus. at the receiving terminal the sulfur slurry be filtered and washed. The recovered sulfur is then melted and purified by liquidliquid extraction with an aromatic hydrocarbon such as cumene. Also, if desired, the sulfur can be steam stripped to remove any dissolved solvent and then filtered to recover bright yellow sulfur.

The foregoing description of the invention is merely intended to be explanatory thereof. Various changes in the details of the described method may be made within the scope of the appended claims without departing from the spirit of the invention.

lclaim:

l. A method of transporting sulfur through a pipeline to a terminal without causing sulfur sticking, agglomeration and plugging of the line comprising:

a. mixing with a liquid petroleum fraction selected from the group consisting of petroleum distillate and petroleum condensate fractions, a small amount of from about 0.1

percent to about 10 percent of an asphaltenic material to form a liquid petroleum mixture;

b. injecting l075 percent molten sulfur into liquid petroleum mixture (a) to form a sulfur-liquid petroleum mixture slurry;

c. injecting the slurry (b) into a pipeline; and

d. transporting via said pipeline slurry (c) to a terminal station.

2. The method of claim 1 wherein the liquid petroleum fraction of (a) is a petroleum condensate containing from l0 percent to 30 percent aromatic components.

3. The method of claim 1 wherein the slurry contains 30- 70 percent by weight sulfur and the balance being a liquid petroleum condensate and the asphaltenic material is asphaltene present in an amount of from about 0.5 percent to about 5 percent.

4. The method of claim 1 wherein the slurry is separated into its component parts at the terminal end of the pipeline.

5. The method of claim 4 wherein the separated components of sulfur and petroleum fractions are each purified by removal of contaminants therefrom.

Claims (4)

1. 2. The method of claim 1 wherein the liquid petroleum fraction of (a) is a petroleum condensate containing from 10 percent to 30 percent aromatic components.
2. 3. The method of claim 1 wherein the slurry contains 30-70 percent by weight sulfur and the balance being a liquid petroleum condensate and the asphaltenic material is asphaltene present in an amount of from about 0.5 percent to about 5 percent.
3. 4. The method of claim 1 wherein the slurry is separated into its component parts at the terminal end of the pipeline.
4. 5. The method of claim 4 wherein the separated components of sulfur and petroleum fractions are each purified by removal of contaminants therefrom.