United States Patent (19) 11) 4,116,812 Godar et al. 45) Sep. 26, 1978

(54) ORGANO-SULFUR COMPOUNDS AS HIGH 3,407,240 10/1968 Sakashita et al...... 260/666.5 TEMPERATURE ANT FOULANTS Primary Examiner-Delbert E. Gantz 75 Inventors: Richard L. Godar; Philip R. Corneli, Assistant Examiner-G. E. Schmitkons both of St. Louis, Mo. Attorney, Agent, or Firm-Sidney B. Ring; Hyman F. (73) Assignee: Petrolite Corporation, St. Louis, Mo. Glass 21 Appl. No.: 813,193 57 ABSTRACT 22 Filed: Jul. 5, 1977 This invention relates to a process of inhibiting or pre venting fouling (i.e., preventing the adhesion of deposits (51) Int. C.’...... C10G 9/16; C08K 5/36; C10C 7/18 from hydrocarbon on surfaces) at elevated temperatures (52) U.S. C...... 208/48 AA; 203/8; which comprises adding to hydrocarbon an antifouling 203/58; 208/106; 208/264; 252/45; 252/77; (preventing) amount of an organo-sulfur compounds 252/406; 260/45.7 S; 260/327 C having a high sulfur content. In the preferred embodi 58 Field of Search ...... 208/48 AA; 260/666.5, ment, the organo-sulfur compound has at least 5% sul 260/327 C fur. An embodiment is a heterocyclic compound, a dithiole-thione. These organo sulfur compounds are (56) References Cited particularly effective at elevated temperatures of at U.S. PATENT DOCUMENTS least about 500 F. 2,129,693 9/1938 Houdry ...... 208/119 3,197,396 7/1965 Stedman ...... 208/189 5 Claims, No Drawings 4,116,812 1. 2 deposits by petroleum hydrocarbon liquids in contact ORGANO-SULFUR COMPOUNDS AS HIGH, with heat transfer equipment. TEMPERATURE ANTIFOULANTS Yet another object is to furnish a chemical treatment This invention relates to a method of chemically capable of being combined with a thermally unstable, treating hydrocarbon liquids which contact surfaces deposit-forming liquid whereby said liquid will not under high temperature conditions in order to inhibit, form deposits upon metal surfaces at elevated tempera prevent and/or reduce the deposition of substances tures. thereon. More specifically, this invention relates to the Still another object is to provide a chemical treatment chemical treatment of the metal surfaces in contact with which will remove high temperature deposits from petroleum hydrocarbon liquids under conditions of 10 metal surfaces of petroleum refining equipment without high temperature whereby said liquids tend to form the necessity of stopping the operations of such equip deposits on such metal surfaces. This invention also ment. Other objects will appear hereinafter. relates to compositions employed in these processes. We have now discovered a process of preventing, In the processing of hydrocarbon liquids, particularly inhibiting and/or reducing the formation of surface petroleum hydrocarbon liquids, elevated temperatures 15 deposits from petroleum hydrocarbon liquids during are often used in many necessary and important opera the processing thereof at elevated temperatures such as tions. To handle liquids at elevated temperatures, heat from about 500-1,500 F. (i.e., the adhesion of deposits exchangers and the like devices are often employed to to heat exchange metal surfaces) by adding to the hy control the heat transfer rate from one operational step drocarbon liquid such as by solution and/or dispersion to another. When hydrocarbon liquids contact hot 20 an anti-fouling amount of the organo-sulfur composi metal surfaces, there is sometimes a tendency for the tions of this invention. liquid to decompose or undergo a chemical reaction The anti-fouling additive system of this invention can that manifests itself in the form of deposits. These de be employed in refining crude petroleum as well as in posits may be either coke-like or they may be in the the treatment of any component thereof which are ex form of tenacious, soft, sticky sludges which adhere to 25 posed to high temperatures including the light distill hot surfaces. Adherences of deposits, rather than depos lates, for example light naphthas, intermediate naph it-formation itself, is the essence of the problem, in con thas, heavy naphthas, etc.; middle distillates, for exam tract to fuel storage where residue in the oil itself cre ple kerosene, gas, oil, etc.; distillate lube oil stocks for ates the problem. example, white oil, saturating oil, light lube oil, medium The problem is well recognized in the art - note 30 lube oil, heavy lube oil, and the like. "Petroleum Products Handbook,' Guthrie (McGraw The amount of anti-fouling agent required in this Hill, 1960) pp. 1-13, U.S. Pat. No. 2,908,824 and else invention is subject to wide variation but in general where. very effective results have been obtained by adding These deposits tend to materially decrease the heat 35 relatively minute amounts of the anti-fouling agent to transfer capacities of the metal surfaces and hence in the hydrocarbon liquid being processed, for example, crease operating expenses. These deposits also require amounts may be as low as 0.5 p.p.m. in hydrocarbon additional effort and time to remove and to restore the liquid, for example 1 to 500 p.p.m. In general, the upper equipment to its original operating efficiency. limit is determined by the economics of the process but Petroleum refinery, operations often encounter the other factors should be taken into consideration, such as above described conditions in many stages in the refin whether large amounts will have any adverse effects on ing process. These deposits form on heat transfer sur present or subsequent operations. Because of the many faces at temperatures for example such as about different types of operatios where hydrocarbons are 150-225 F. and may be evidenced at temperatures as heated to elevated temperatures under conditions extreme as 1000 F. or higher. 45 where deposits are formed, it is difficult to give specific It is practically impossible to prevent these deposits ranges which will be effective in all operations. The by coating the metal surfaces with a protective perma amount of agent which inhibits the formation of depos. nent coating due to the possible loss of heat transfer. In its is referred to herein as an "anti-fouling amount.” The addition, the large volume of liquid that contacts such above figures relate to p.p.m. in terms of active anti equipment increases the problem of treating metal sur 50 fouling chemical not including the solvent employed. faces in petroleum processing to prevent high tempera Inasmuch as the anti-fouling agent is employed in ture deposits. such small amounts and it is preferable to feed them It would be advantageous to add a chemical agent in continuously or semi-continuously by means of a pro extremely small amounts to a hydrocarbon liquid which portioning pump or other suitable device to the particu tends to form high temperature deposits whereby such 55 lar hydrocarbon liquid being processed or to add them deposits would be inhibited or prevented. It would also in a similar manner to the apparatus in which the hydro be desirable if such a chemical would not only prevent carbon liquid is being processed, it is desirable to incor such deposits but would also remove them without porate the agent or a mixture of agents into a suitable ... necessitating the stoppage of a given operation. It there solvent which will be compatible with the liquid which fore becomes an object of the present invention to pre is to be processed. The solvent which is used to dissolv vent the formation of high temperature deposits on the active ingredient is also subject to some variatio) metal surfaces by chemical means. . . depending upon the solubility characteristics of th Another object is to furnish a chemical which when particular compound employed. In some cases, eve added to a hydrocarbon liquid will prevent the deposit though the active mixture is insoluble in a particula forming tendencies of said liquid when it contacts metal 65 solvent, it will dissolve in a combination of solvents. surfaces at elevated temperatures. In the practice of the invention it is very desirable t A further object is to provide a chemical treatment start the treatment with the chemicals employed for th which will prevent the formation of high temperature purpose of the invention at a higher dosage and the 4,116,812 3 4. gradually reduce the dosage to the point wherefouling lized from benzene, red crystals, (32 grams, 50% yield), of the apparatus is just eliminated. The organo-sulfur compositions of this invention m.p. 122-124° C. have a high sulfur content. In general, the sulfur content EXAMPLE 2A: Preparation of is from about 5 to 60% or more, such as from about 10 4-(3-methoxy-4-hydroxy)phenyl-1,2-dithiole-3-thione to 55%, for example from about 20 to 50%, but prefera bly from about 25 to 45%. In a suitable reactor equipped with a stirrer, ther An embodiment of organo-sulfur compositions of mometer, addition funnel and reflux condenser was high sulfur content includes heterocyclic compounds, placed, 32 g of sulfur, 1.0 g of di-o-tolylguanidine as an example of which comprises dithiole-thiones as illus 10 catalyst and 150 cc of mesitylene as solvent. The mix trated by 1,2-dithiole-3-thiones. ture was brought to a reflux (170° C) and over a 1 hour 1,2-dithiole-3-thiones are known compounds pre period 66 g of isoclugenol pared by a variety of methods. Examples of such com pounds, and methods for their preparation, are dis closed in THE CHEMISTRY OF HETEROCYCLIC 15 COMPOUNDS, "Multi-Sulfur and Sulfur and Oxygen Five-and Six-Membered Heterocycles," PART 1, pages HO CH-CH=CH, 237-386, by David S. Breslow et al., Interscience Pub lishers, 1966. CHO 1,2-dithiole-3-thiones may be expressed by the for 20 mula: was added dropwise. Reflux was continued for 48 more S hours. The mesitylene was decanted from the solid. The solid was treated twice with 500 cc portion of a 5% S 25 aqueous potassium hydroxide solution. Upon acidifi CES cation the product precipitated as a brown solid. where R and R' are substituted groups, for example, EXAMPLE 3A: Preparation of alkyl, aryl, cycloalkyl, alkenyl, alkynyl, alkaryl, aralkyl, 4-neopentyl-5-t-butyl-1,2-dithiole-3-thione heterocyclic, etc. In addition, one of the above R's may 30 be hydrogen. Examples of a wide variety of 1,2-dithi To a mixture of 320 g of sulfur and 6.0 g of di-o-tolyl ole-3-thiones are presented in the above text by Breslow guanidine was added over a 9 hour period, at a reaction et al in Table 4, pages 352–366, which is incorporated temperature of 210-215 C., 336 g of triisobutylene, into this application as if part hereof. mainly 1,2-dithiole-3-thiones are conveniently prepared by 35 the classic method of reacting an olefin with sulfur, for example, according to the following equation: (CHC-CH=CH- C(CH), CH, S / N R-C S Heating at 210-215° C. was continued for an additional RCH camef cH, -ss-s- R-C CS 14 hours. The product was distilled and there was col R lected 220 g of 4-neopentyl-5-t-butyl-1,2-dithiole-3- thione, b.p. 155-185° C. (3-4 mm Hg). The olefin employed in the reaction contains 45 1. a reactive double bond S 2. a primary carbon atom / 3. at least four hydrogen atoms on the 3 terminal (CH-c- carbons with at least one hydrogen on the carbon beta (CH),CCH, -C CaS to primary carbon atom. SO This reaction is carried out at any suitable tempera ture and time, for example, at about 100 to 300 C., EXAMPLE 4A: Preparation of . such as from about 140 to 240 C, but preferably from 4,5-tetramethylene-1,2-dithiole-3-thione about 160 to 220 C. for a period of about 2 to 160 hours, and about 10 to 50 hours, but preferably about 15 55 In a suitable reactor equipped with a stirrer, reflux to 40 hours. condenser, thermometer and addition funnel was placed The following examples are presented by way of 24 g. of sulfur, 171 g of carbon disulfide and 150 cc of illustration and not of limitation to show the preparation dimethyl formamide. The mixture was cooled to 0° C. of 1,2-dithiole-3-thiones. and under continuous stirring and cooling 132 g of EXAMPLE 1A: The Preparation of 60 1-morpholino-1-cyclohexene was introduced over a 4-phenyl-1,2-dithiole-3-thione hour period. After the addition was completed, stirring In a suitable reactor equipped with a stirrer, ther was continued for an additional 16 hrs. The resulting mometer and a reflux condenser, was placed 118 g of slurry was poured into water and the resulting orange methylstyrene and 48 g of sulfur. The mixture was 65 solid crystallization from acetone, m.p. 95-97 C. Yield heated for 37 hours at 200-210 C. After the reaction 37%. was completed, the mixture was slowly cooled to room The following Table presents illustrative 1,2-dithiole temperature. The product was collected and crystal 3-thiones of the formula

4,116,812 7 Few, if any, of commercial antifoulants now sold are -continued capable of effectively inhibiting fouling in high temper Furnace Outlet Temp. ature process heater, i.e., above about 500 F., such as Regular Coke 925 F from about 500-1500' F., for example, from about 500 Needle Coke 945°F to 1200 F., but preferably from about 800 F. to 1000' s Coke Drum Pressure 20 psi F. One example of a high temperature fouling occurs in EXAMPLE 2. delayed coking operations of petroleum refining. This is A typical furnace fouling problem occurred in a de best illustrated by fouling occurring in the coker fur 10 layed coker even though a commercial antifoulant was nace and in the long transfer line between the coker injected into the furnace charge at 24 ppm. Three furnace and the coke drums. Such "coke' buildup re months into a run, the pressure drop across the furnace quires periodic cleaning (decoking) of such lines, during had reached 290 psi. A pressure drop of 320 psi is con which operation of the unit is curtailed. sidered limiting and necessitates a decoking operation. The coker in a refinery relates to the collection of 15 At this point the commercial antifoulant was replaced bottoms from the refinery operation, the heating of such with the compound of Example 3A at 8 ppm and the bottoms in the coking furnace to high temperature of pressure drop lined out at 295 psi without further in about 900 F. or higher so as to remove and collect the Cease, volatile fractions and the transportation through pipe Typical operating conditions are as follows: conduits to coke drums for later use, for example, as 20 high grade coke, etc. The bottoms pass through heat Charge 5000 BMD exchange conduits in the coking furnace and then Furnace Inlet Temp. 680 F. Furnace Outlet Temp.: through conduits to the coke drums where they are Regular Coke 92 F. collected. In going through the conduits, fouling occurs Needle Coke 945 F. through a buildup by adhesion of deposits on the inside 25 Furnace Pressure clean 210 psi of the conduits resulting in pressure buildup and loss of Furnace Pressure fouled 320 psi heat transfer efficiency due to the smaller diameters of the fouled conduits. When the pressure buildup be We claim: comes sufficiently great, the conduits have to be 1. A process of inhibiting the adhesion of deposits 30 from hydrocarbons on metallic surfaces of the treating cleaned (decoked). apparatus when said hydrocarbons are treated at ele The following examples are presented for purposes of vated temperatures of from about 500' F. to about 1500 illustration and not of limitation. F. which comprises adding to said hydrocarbons during EXAMPLE 1. the treatment process an inhibiting amount of a hetero 35 cyclic organo-sulfur compound of high sulfur content A Midwestern refinery experienced severe fouling in having the formula the long transfer line between coke furnace and coke drums. Once deposits began, pressure at the beginning S of the line increased rapidly and the lines had to be / N decoked when the pressure reached 200 psi. This oc- 40 curred over a period of about 90 days. CS After decoking was effected, the composition of the formula (Ex. 3A) where R and R' which may be the same or different are hydrogen or a substituted group. S 45 2. The process of claim 1 where the organo-sulfur / N compound has at least 5% sulfur. (CH,)-C-C S 3. The process of claim 2 where the organo-sulfur (CH.)CCH-C CS compound has from about 25% to 45% sulfur. 4. The process of claim 1 where the organo-sulfur was injected at about 20 ppm into the coker furnace 50 compound is present in an amount of at least 0.5 p.p.m. feed. After about 100 days the additive concentration in the hydrocarbon liquid. was reduced by and kept at this concentration. No 5. The process of claim 1 where the organo-sulfur pressure buildup occurred through the coking furnace compound is has been in operation over a period of many months. S Typical operating conditions are as follows: 55 M. N. (CH)-c- i Charge 4400 BMO (CH)CCH, -C C=s Cycle 24 hours Coke Type Regular and Needle Furnace Inlet Temp. 580-600 F 60

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