PETROLEUM REFINERIES
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Pollution Abatement at Sinclair Refining Company N. J. GOTHARD, Sinclair RefZning Co., Harveg, Ill. J. A. FOWLER, SincCair Refining Co., East Chicago, Ind. T h e progress which has been made by the petroleum refining industry in the field of pollution abatement has been, to a great extent, the result of technical information developed by the American Petroleum Institute Committee on Disposal of Refinery Wastes. The Sinclair Refining Co. at East Chicago, Ind., has taken advantage of the work of this committee to formulate a program for pollution abatement. The basic features of this program are outlined in this paper. As a result of this program, the
volume of the total refinery effluent is approximately 5000 gallons per minute. Without the benefits of cooling towers and other volume-reducing measures employed, the effluent on the present 90,000-barrel-per-day refinery would be approximately 100,000 gallons per minute. The effect of concentration of soluble pollutants has been observed, but tests show R great reduction in net pollution as a result of the Sinclair program for pollution abatement.
T
HE reeord of the petroleum refining industry in the United
an effluent as good as or better than t h a t of other industries States with regard to pollution abatement and waste disin the same area. However, the time was foreseen when all posal has been very much the same as t h a t of industry a s a whole. industries in the area would be required t o improve t h e quality There was a period which lasted until about 1920 when very little of their effluent; therefore, Sinclair began to study the problem consideration was given to pollution abatement, and waste disof pollution abatement so t h a t when i t became advisable to do BO, posal was considered primarily a problem of recovering from the the refinery would be ready to put into effect the best possible refinery effluent all the oil which copld be recovered in a simple plan for handling refinery wastes, gravity-type oil separator. About 1920, however, industry beAs a result of the law suit Illinois 08. Indiana et al., United came more conscious of its responsibility with regard to pollution States Supreme Court, filed October 9, 1943, a number of indusabatement. This change in attitude was partly spontaneous and tries in the Calumet region were charged with the pollution of partly the result of legislation, both state and federal. Lake Michigan and ordered to submit a plan to the court for imI n the petroleum industry, the American Petroleum Institute, proving their waste disposal systems. T h e plan which Sinclair which was organized in 1919, was quick to realize the importance submitted to the court involved some fundamental changes in of pollution abatement, and appointed a Committee on Oil Polrefinery operation and affected materially the thinking with relution Prevention. This original committee was lacking in techgard to the future development of the refinery; therefore, much nical background and made little progress, but in 1930, after rethought was put into developing a plan which would work to t h e organization into the Committee on Disposal of Refinery Wastes, advantage of Sinclair from the standpoint of plant operation, it began a constructive attack on the problem of pollution abatebut the primary consideration in developing the plan was pollument. This committee has continued its activity through the tion abatement with the purpose of cooperating with the states years and has succeeded in accumulating a large amount of techof Indiana and Illinois in their efforts t o reduce t h e pollution nical data which has been published in a manual dealing with entering Lake Michigan. This plan, adopted as the Sinclair nearly every phase of pollution abatement as i t concerns petroprogram for pollution abatement, has been p u t into effect, and leum refiners. This manual is available to the public and has Sinclair has been dismissed from the law suit. been used to great advantage by the Sinclair Refining Co. in deThe purpose of this paper is to describe the Sinclair program veloping a program for pollution abatement. for pollution abatement and to discuss the results obtained from The history of the putting this program Sinclair Refining Co. into effect, at East Chicago, Ind., This program for with regard to pollupollution abatement, tion abatement has a s dealt with in this paralleled very closely paper, refers only t o t h a t of the petroleum pollution b y waste refining industry as water; air pollution is a whole. When the not included. T h e refinery was built, basic features of this around 1920, a single program are: sewer s y s t e m w a s 1. Separation of constructed to handle sanitary sewage from all waste water, and a other refinery wastes. gravity-type oil sepa2. Reduction o f rator of the best dethe over-all volume sign known at t h a t of refinery wastes to a time was i n s t a l l e d . minimum, primarily This system of hanby the installation of dling wastes servedits c o o l i n g towers for View of the API Separator p u r p o s e f o r many recycling cooling Primary chambers on right years and produced water. Three effluent pumps on left pump the entire refinery effluent March 1952
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Liquid Industrial Wastes some form during the process of refining and, therefore, normally is contaminated. Cooling water constitutes by far the larger volume of the two classes, amounting a t the present time to approximately 97,000 gallons per minute a t East Chicago as compared with approximately 4250 gallons per minute of process water. I n developing a plan for pollution abatement, a refinery must decide whether cooling water will be used on a once-through basis or whether cooling towers will be installed for recycling the cooling \% ater. I n the case of refineries located in arid sections of the country, there is usually no choice to be made-the cooling tower method of handling cooling water is a necessity: but in the case of r e h e r y located on Lake Michigan where the supply of fresh water is bountiful, it would seem on first thought that the once-through method of handling cooling water would be more logical. If the once-through method is chosen, the refinery has the problem of providing adequate oil-separating equipment for a large volume of water. It is true t h a t normally this water is not contaminated with oil, but there is always the possibility of oil leaks; therefore, adequate oilseparating equipment must be provided. The cooling water may be segregated and handled in a separate sewer system and in a less expensively constructed oil separator than normally is required for process water, but in an old refinery built on the one-sewer system, the separation of cooling watgr from process water and the building of a separate sewer system for this water is a major problem. If the cooling tower method of handling cooling water is chosen, there are problems also which must be solved: cooling towers are expensive and occupy valuable space within the refinery; fur,.v thermore, they present operating problems and L I expense. Figure 1. Location of Sinclair Refining C o . in the Calumet Region The matter of available space for separators as compared with cooling totvers, cost of construction, operating expense, etc., were considered carefully at With regard to the other features of the Sinclair program, some East Chicago, but in the final analysis, the cooling toner facts about the refinery as i t exists today are needed in order to method of handling cooling water vias chosen because the explain why such a program was adopted. Sinclair management believed that cutting down the size of the The East Chicago refinery is located on a branch of the Indiana harbor ship canal approximately three miles from Lalie Michigan. over-all effluent would enable the company to do a better job There is very little flow in the canal adjacent to the refinery, and in reducing the amount of pollution going t o Lake Michigan, regardless of future trends in refining processes and governany Tvastes, part,icularly oil, discharged into the canal at that, ment requirements. point tend to accumulate and van be observed easily. Figure 1 In converting to the cooling tower system, Sinclair has cons h o w the location of the refinery n-ith relation to Lake Michigan. stiucted five cooling towers with a total capacity of 97,000 gallons The East Chicago refinery is a complete refinery with a crude per minute. This cooling capacity is adequate for all present capacity of 90,000 to 95,000 barrels per day. The principal proccooling and condensing needs. Nevi cooling towers will be added esses in use are: crude distillation, thermal cracking, fluid catain the future when made necessary by new refinery units, and the lytic cracking, polymerization, alkylation, grease making, light addition of new cooling towers will result in only a small increase oil treating (consisting of caustic washing, doctor treating, and in the over-all volume of the effluent. This fact makes the coolcopper chloride treating), and lubricating oil and wax treating ing tower system more flexible, in that the addition of new units (consisting of propane deasphalting, phenol extract'ion, methyl to the refinery has little effect on the established method of et,hyl ketone dewasing, clay contacting, and acid treating). handling wastes. Residual cmde bottoms and ta,rs are made into heavy fuel oil. As pointed out before, process water comes in contact with chemicals or oil during the refining process and requires very Redaction of Over-all Volume of Efflnent careful handling in the waste disposal system. Therefore, any measures which can be taken to reduce the volume of process As is the case with all oil refineries, large volumes of water must nater will reduce the size of the oil-separating equipment rebe used, and it is the disposal of this water after use that constiquired and will aid generally in the problem of pollution abatetutes the pollution abatement problem. Excluding sanitary ment. wastes, which have been considered previously, refinery waste At East Chicago, important reductions have been made by water falls into two classes-spent cooling water and waste proceconomy campaigns in which the men who operate the units were ess water. Spent cooling water is water which has been used for convinced of the necessity of reducing to the minimum the volume cooling only in surface condensers or heat exchangers and norof water used in the various processes. Where water is pleutiful, mally does not come in contact with chemicals or oil. M7aste the idea of economy is hard to sell, but it can be sold by emphasizr has contacted chemicals or oil in process water 1s ~ a t e mhich 3. Construction of a n American Petroleum Institute oil separator of adequate capacity for the reduced over-all effluent. 4. Treat,ment of heavily polluted wastes a t their source before they enter the refinery sewer. With regard t o the handling of eanitary sewage, little need be said. In a modern refinery, the segregation of sanitary sewage is accepted as a necessity, both for sanitary reasons and because of the harmful effects which the solids from sanitary wastes have on the operation of oil-water separators. The sanitary sewer constructed by Sinclair a t East Chicago completely separates sanitary sewage from other refinery wastes and delivers the sewage to the East Chicago, Ind., sewage disposal plant.
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INDUSTRIAL AND ENGINEERING CHEMISTRY
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Liquid Industrial Wastes ing the fact that economy is necessary because of disposal problems rather than because of supply. In some cases, new construction or changes in process were made for the purpose of reducing the volume of waste process water. One notable example of this p a s the remodeling of the light oil-treating plant. Rock and salt towers were installed to remove traces of the treating agent remaining in the oil, thereby eliminating the necessity of washing the treated oil with water. By this means, approximately 1800 gallons per minute of wash water, polluted with oil, sulfides, and phenols, were eliminated from the sewer. Figure 2 is a simple flow diagram illustrating the rock and salt tower installations.
ROCK TOWER
SILT TOWER
The separator was designed strictly according to the 1949 edition of the American Petroleum Institute “Manual on Disposal of Refinery Wastes” (1) and consists of three two-stage units. Each unit is 18 feet wide and consists of aprimary and a secondary chamber. The primary and secondary chambers are 41 feet and 57.4 feet, respectively, in effective length, and the design water depths are 7.5 feet and 7.05 feet, respectively. Flight scrapers were installed in both primary and secondary chambers to accumulate the oil and sludge for removal from the separator. There was never any question as to what type of oil separator would be installed. The API separator design has been developed by the API Committee on Disposal of Refinery Wastes and is the only separator design widely accepted in the petroleum industry for the removal of oil from a refinery effluent. The separator has been in operation a t East Chicago for two years. During the last year and one half the refinery effluent has averaged 5500 gallons per minute with an average oil content of 100 parts per million. Duiing the same period the oil recovered from separator skimmings averaged 638 barrels per’day. If total oil entering the separator is assumed to be the oil recovered from the separator skimmings plus the oil carried out in the effluent, the oil recovery during the last year and one half of operation has amounted to 97.3%.
--id
Treatment at Source esrr, 7 a s,wm
F i g u r e 2.
Rock and Salt Towers at Light Oil-Treating Plant Tower dimensions, 9 X 20 feet Depth of gravel and salt beds, 15 feet Flow through unit, 600 barrels per hour
Another example was the installation of a stainless steel mat (called demister) in the asphalt stripper a t the propane deasphalting plant. Steam is used in this stripper to remove traces of propane left in the asphalt, and the stripping steam is later condensed in a spray condenser. Prior t o the installation of the stainless steel mat, a small quantity of asphalt was carried over from the stripper into the spray condenser, making the effluent from the spray condenser unfit for recycling in the cooling tower. T h e stainless steel mat prevents the carry-over of asphalt, making it possible to recycle the spray condenser water in the cooling tower. This installation eliminates approximately 500 gallons per minute of asphalt-contaminated water from the sewer. Figure 3 shows how the stainless steel mat was installed. Another project which is in the construction stage at East Chicago is a “dirty water” cooling tower. The construction of this cooling tower is in line with the established policy of providing additional cooling tower capacity for new units. This cooling tower, in addition to providing cooling water for a new unit under construction, will permit a reduction in volume of the present effluent, because approximately 1000 gallons per minute of oiL bearing barometric condenser water, which now goes to the sewer, will be recycled in this tower.
Construction of API Oil. Separator One of the primary reasons for reducing the volume of the effluent was t o reduce the size of the oil-water separator required. It was estimated that the volume of the effluent would be approximately 3000 to 3500 gallons per minute after the measures which have already been described were taken. T o handle such a n effluent, a n API oil separator was designed for the following conditions: Capacity Gravity of waste oil Temperature of waste water
March 1952
7500 gallons per minute 30° API 60° F.
In any system of handling wastes, the most logical place to eliminate pollution is a t its source before it enters the sewer. This is to some extent a matter of good housekeeping and can be accomplished at tho various refinery units by the operators. I n line with this thinking, every effort is made a t East Chicago to obtain the cooperation of the operators in keeping pollution out of the sewers, and the operators are usually willing to cooperate in this matter if they are properly convinced of its importance.
Figure 3.
Stainless Steel Mat Installed in Asphalt Stripper
Tower dimensions, inside diameter, 6 feet Thickness of mat, 4 inches Stripping steam, 250 pounds per hour
In addition to good housekeeping, it is sometimes necessary to constnict auxiliary equipment for the removal of pollution at its source. Two units have been built a t East Chicago for the sole purpose of handling pollution at its source. One of these is a waste caustic-treating unit. All waste caustic produced in the refinery is collected at this unit and treated by contact with air and steam in a packed tower. The sulfides in the waste caustic are thereby converted to thiosulfates which are discharged in the effluent. This unit operates with a conversion of approximately 95%. Figure 4 is a simple flow diagram of the waste caustictreating unit. Another unit constructed for the purpose of removing pollution a t its source is a steam stripper designed t o remove ammonia and hydrogen sulfide from the overhead accumulator water
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L i q u i d Industrial Wastes at the fluid catalytic cracking unit. Approximately 55 gallons per minute of accumulator water, containing approximately 5000 parts per million each of hydrogen sulfide and ammonia, is charged to this ammonia-hydrogen sulfide stripper. The effluent from the stripper contains approximately 50 parts per million of bydrogen sulfide and 600 parts per million of ammonia, representing a removal of 99 and SS%, respectively. The ammonia and hydrogen sulfide stripped from the accumulator water are burned in a furnace at the fluid unit. Figure 5 is a simple flow diagram of the ammonia-hydrogen sulfide stripper.
+
.%"/Ell
Figure 4.
Waste Caustic-Treating Unit
Tower dimensions, 5 X 44 feet Depth of packing, 4 feet Liquid level in tower. 0 t o 10 feet Feed t o unit, 3 barrels per hour of spent caustic Air to unit, 16,000 cubic feet per hour Stripping steam t o unit, 700 pounds per hour
Due to the operation of the waste caustic-treating unit and the ammonia-hydrogen sulfide stripper, sulfides virtually have been eliminated as a waste disposal problem a t East Chicago. In addition, certain measures are being taken to remove phenols at the source. A portion of the ammonia-hydrogen sulfide stripper bottoms is being fed to a cooling tower where the phenolic material is removed, probably by a combination of biological and chemical oxidation. This operation is still in the experimental stage, but a t present appears to have good possibilities. Blso, a portion of the spent caustic which contains the highest concentration of phenolic compounds and which othern-ise would be fed t o the spent caustic-treating unit is accumulated and sold to a chemical company for the phenolic content.
and total hardness in the circulating water amounts to approximately three concentrations. The effect of concentration due to reducing the volume of the refinery effluent has caused some concern a t East Chicago. If pollution were considered only on the basis of parts per million, there would be no justification for reducing the volume of the effluent and the East Chicago effluent would show no improvement; however, on the basis of net pollution in pounds per day, i t is apparent t h a t the actual pollution contributed by the 5000 gallons per minute effluent is riot grew B 100,000 gallon. per minute effluent, which is approximately what the East Chicago effluent would be without cooling towers, containing only 4 parts per million of oil would be equivalent in oil pollution to thc 5008 gallons per minute effluent containing 80 parts per million of oil. It is doubtful that any oil separator which could be installed in a refinery would be capable of reducing the oil content to 4 parts per million without the use of chemical flocculation. It is difficult to show by comparative tests just what benefits have been realized from the Sinclair pollution abatement program because the refinery was involved in an extension program a t the same time the pollution abatement program was being put into effect. Hovever, from Table I1 it is apparent that net pollution in the effluent has been decreased materially even though the refinery has been increased from a capacity of 55,000 t o 90,000-95,000 bariels per day. A comparison of the sulfide tests shown in Table I1 do not indicate any great improvement; however, the sulfides on the current effluent without the ammonia-hydrogen sulfide stripper and the waste caustic-treating plant would run approximately 25 parts per million or 1650 pounds per day.
Figul e
506
Ammonia-Hydrogen Sulfide Stripper a t Fluid Catalytic Cracking Lnit
Tower dimensions, 5 X 30 feet Maximum feed to unit, 200 gallons per minute Temperature of feed to tower, 240' F. Temperature of accumulator water, 200' F. BIaximum .stripping hteam to tower, 6000 pounds per hour
Disoassion of Resnlts The most important part of the Sinclair program for pollution abatement is the reduction of the over-all volume of the effluent. At present, the volume of the effluent averages approximately 5000 gallons per minute, Without the reductions made by the installation of cooling tov, ers and the measures designed to reduce process water, the over-all effluent would be approximately 100,000 gallons per minute. Table I shows the contribution t o the over-all effluent made by the various units in the refinery Figure 6 is a general flow sheet showing the route of wastes through the plant. The data in Table I1 represents current refmery operation and shows the volume of the over-all refinery effluent to be 5000 gallons per minute. Approximately 750 gallons per minute of the over-all effluent is cooling tower blowdowns; the remainder-4250 gallons per minute-is waste process water. The dirty water cooling tower, now under construction, and other minor changes in operation, now being made, will reduce the over-all effluent to approximately 3000 gallons per minute. The 750 gallons per minute of cooling tower blowdowns amount to approximately 0.75% of the cooling tower circulation. Taking blowdowns a t this rate, the build-up of dissolved solids
5.
Table I.
Sources of Waste Water, East Chicago Refinery Gallons per Minute
Lubricating oil-treating plant Light oil-treating plant R-ax plant Polymerization a n d alkylation plant Lube addend plant Straight run-fractionating unit Fluid catalytic cracking unit Thermal cracking a n d crude redriotion Lube oil still Combination crude and thermal cracki ng still Two crude stills Two shell stills Main laboratory Barrel house Drum washing plant Total process water Cooling tower blowdowns froin 5 cooling towersa Total refinery effluent 0
440 25 1000 110 50 100 190 600 10 625 545
380 50 50
75 __ 4280
760 5000
Total circulation capacity of 97,000 gallons per minute
INDUSTRIAL AND ENGINEERING CHEMISTRY
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LiquZd Industrial Wastes Table 11.
I
Tests on East Chicago Refinery Effluent
000-Barrel-per-Day Crude Capacity 34,000
J
2.5 150 20 0
1.0
410 26
1200 80 4300
10,600 Oils, p.p.m. Oils, lb./day
TO /ND/AMA H A R B O R
Figure 6.
S U / P CANAL
General Flow of Refinery Wastes
After reducing the over-all efluent to the present 5000 gallons per minute and eliminating sulfides as a problem, the remaining pollution problems at the East Chicago refinery are concerned primarily with phenol and oil. A completely satisfactory method for removing phenols is not known a t this time, but the problem is being studied extensively by Sinclair as well as many other companies, and a satisfactory solution to the problem undoubtedly will be found. The oil problem exists a t East Chicago primarily because of suspended solids and emulsions which interfere with oil separation in the API separator. Susceptibility to separation tests indicates that the separator is removing all the oil which it is capable of removing from the effluent as it exists a t the present time. The problem, therefore, is to find a means of eliminating suspended solids and emulsions from the refinery sewers. This problem is
Barrel-per-Day Crude Capacity 5000
23
8,440
being studied from many angles a t East Chicago, and on the basis of experimental results obtained on a pilot unit, it appears that a precoat vacuum iilter will go a long way toward solving the emulsion and suspended solids problem. The oil problem is also affected by flow in the separator, and when the flow is further reduced to 30y gallons per minute, as previously discussed, an increase in the efficiency of the separator will undoubtedly occur. As stated before, Sinclair realizes that the reduction-of-volume approach to pollution abatement has created some problems, but from the over-all standpoint, the company is convinced t h a t such an approach was the best possible for the East Chicago refinery, and that the problems which still exist and the problems which may come up in the future will be solved more easily by virtue of the fact that the effluent has been reduced in volume.
Literature Cited (1) American P e t r o l e u m I n s t i t u t e , “ M a n u a l o n Disposal of Refinery Wastes,” N e w Y o r k , 1949.
RECEIVED for review September 6, 1951.
ACCEPTED January 15, 1952.
Pulp and Paper Industry HAROLD R. MURDOCE, ConeultZng Chemical EngZneer, 2025 Peachtree Rd., N.E., Atlanta, Ga. AI1 previous production records of the pulp, paper, and paperboard industries were surmounted in 1950. Production has almost doubled in the past ten years. To cope with the resultant increase in stream pollution, national and regional organizations have been established by the industry to study the problems. These scientists with outstanding experience have fulfilled their objective well.
In another decade, modern methods and well-designed equipment will have reduced stream pollution from the pulp and paper industry to a matter of little importance. New mills bave already demonstrated this trend. A s supply and demand for pulp and paper products become more balanced, competition will force older mills to modernize their operations or close down.
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discharged into the municipal system. Similar specific orders for correction were given the other mills. The dumping of waste sulfite liquor and the discharge of wood pulp fibers into the river underline all the orders. The mills have now submitted their plan of correction (97). The bookpaper mill (19) accepted reduction in production rather than spend over a million dollars for installatien of equipment not fully proved for correcting sulfite liquor pollution. The kraft mill has complied with t h e state order and the other sulfite mills have announced plans (21) for building a recovery plant t o cost well over a million dollars for evaporating and burning the spent calcium-base sulfite liquor. In some cases the mills are changing details in pulping technique. Complete descriptions and full specifications with flow chart and drawings have been filed. Other Wisconsin mills not cited in t h e February 21, 1950, orders (21)have also told the commission of various changes in their equipment and process to be made t o
ECEXTLY three state pollution control commissions dealt staggering economic blows t o the pulp and paper industry. The talking stage as t o how t o correct pollution nuisances appears t o have ended. Now action is demanded. I n Wisconsin, following public hearings, six pulp and paper mills were told on February 21, 1950, what, when, and how they must meet the requirements of the state commission (17, 18). A bookpaper and sulfite pulp mill built some 35 years ago was ordered t o reduce discharge of wood fiber t o a practical minimum; reduce the average daily waste sulfite liquor pollution of Fox River by not less than 40% of the average pollution during July 1 t o Xovember 30, 1948; and install storage tanks in order t o equalize release of remaining waste sulfite liquor into the river. A kraft pulp and paper mill was ordered t o complete t h e present program of modernization and install fiber save-all equipment, and t o alter existing sanitary sewer system so all sewage would be
March 1952
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