!tic Methanol Producri
c
b
t
A Staff-lndustrg Ce”-%rative Repor’. MERRITT,L. KASTENS
-
In deboration with
Associate Editor
..
NE of the mwt phenomenal growtb in the record of the American chemical industry is that experienced in the manufactum of synthetic methanol during the pad 20 years. Keyed to that growth, both as muse and eflect, is tbe expansion of formaldehyde pruduction and the advent of tke fordldehyde C y p e plastics. oxidation of methanol to for4)sldehyde ~owuntsfor almost half of the total production. This pemutuge hss remained relatively wnstgnt throughout the history of methanol production. However, steadily increasjng application of the basic phenolformaldehyde type plaetics has indthe actual tomage of methanol ueed for thia purpose manyfdd during the past two decades. Two thirda of the remdning production now is nsed as automobile antifreeae and this a p p b t i o n ia expected to expand as methanol production capscity catches up with exceea demaud (84). Unlike its UBB in formaldehyde production, the uee of methanol m .uMmobile radiators ia a fairly recent application. Althougb it hss a lower h o i i point than the previously used denatured deoM1, ita lower molecular weight given it lesa partial p m u r e 80 that it does not boil away bs fast as the higher alwhol. A t the
II
JAMES F. DUDLr;r Cornlnsrcial Solcents Corpomtion, Term Haute, I d .
JULIUS TROELTZSCH Commercial Solcents Corporation, Sterlington.
0
I La.
present time a considerable volume of ethanol ia still being used for this purpoee. However, methanol producers predict that once they achieve adeqwte production they w i l l split the antifreeze markst about 65 to 35 with ethylene glycol, a a s h g thab glywl prices remain steady. If the price is depressed by the new production provided by Wyandotte Chemical Company, E. I. du Pout de Nemours k Company, and JeiTerson Chemical Company, glycol may claim a larger percentage of the market. If on the other hand, prices follow the upward trend, use of methanol m y hefavored. Some observers feel that ethanol producers will not relinquish this major market without a struggle. However, they must over wme a 25- to h u t per gallon price Werential. One straw in the wind is the withdrawal of D u Pout’s ethanol antifreeze from the market. Beverage alcohol produoera may retain an entry into the market and may even enter into price competition with methanol to retain a stabilieing market for surplus fermentation alcohol. The recency of the antifreeze market ia apparent from a comOarison of oarcentm consumption fimm fm 1930 and 1947:
I
. ~
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
December 1948
Per Cent
--.--_.___I
Formaldehyde (production and stabilization) Denaturant Antifreeze miscellaneous and solvent Dimet hylaniline
1930 (10)
1947 ( 1 2 )
41
44
31 .. 23a 5 I__
ion
Total a
b
delivered in New York, duty paid, a t 40 cents a gallon; this was less than half the going price for domestic wood alcohol.
~~
5
38 13 b
. . ..
1on
Includes antifreeze. Includes dimethylaniline production.
HISTORY O F SYNTHETIC METHANOL Tliii ty years ago there was no commercial production of synthetic methanol. The wood alcohol produced was made by the destructive distillation of wood waste by much the same procedure That Taylor used to obtain what he had named "pyroligneous ether" over a century .before. Methanol was a special chemical used largely as a denaturant in ethyl alcohol. That portion of the 8,000,000 or 9,000,000 gallons prbduced annually which was used as a raw material for further synthesis went into the production of' other special compounds which could absorb the post World TTar I price of almost R dollar a gallon.
The entire methanol synthesis process can be seen here. hTaturalgas enters by the overhead pipe line in the foreground, is reformed in the furnace at the right, cooled in the tall tower at center, compressed in the brick building, and converted to methanol on the converter line under the crane structure seen in left background. Purification is behind reformer furnace.
FOHEIGN DEVELOPMENT
2231
SYNTHETIC METHANOL IN THE UNITED STATES
I n less than 4 years, in the spring of 1927, synthetic methanol was being produced in the United States. The first unit in operation was located in Belle, W. Va., at the ammonia plant of Lazote, Inc., a D u Pont subsidiary. This first installation was essentially an experimental unit installed in conjunction with existing animonia synthesis facilities. The ammonia synthesis gas containing about 1 to 2% carbon monoxide as an impurity was passed through the methanol converter as a purification step. Final traces of carbon monoxide were removed by methanation in a aecond converter. The production of this unit was absorbed completely within the D u Pont organization but it was announced as part of a program designed to supply the entire American d(1mand for methanol. The practice of running a single synthesis gas stream through both methanol and ammonia converters as in the original D u Pont plant is often considered to be the major contribution of American science to the technology of methanol synthesis (IO). It is no longer used in this country but has been adopted widely throughout Europe. I n the summer of 1927, a few months after the Belle installation began production, Commercial Solvents Corporation announced the completion of a synthetic methanol plant a t the Peoria works; this production was to triple the production of synthetic methanol in the United States. Also a by-product unit, this installation used fermentation gas from butyl alcoholacetone production units as its raw material. This gas consisted almost entirely of 60% carbon dioxide and 40% hydrogen. The unit was constructed and operated originally for the production of ammonia. However, after operating less than a month, ammonia production was abandoned and the converters changed over to a unique catalyst which initiated the reaction:
+
+
COz 3H2 +CHiOH HzO I s long ago as 1905 fhbatier had stated the theoirlical possibility of producing methanol by the catalytic combination of The Peoria installation is believed to have been the first comcarbon monoxide and hydrogen but he had no way of determining mercial application of high pressure synthesis from pure carbon the equilibrium of the reaction or the theoretical yield and tie dioxide and hydrogen. The converted methanol plant was annever succeeded in achieving the synthesis even on a laboratory scale. However, the problem was solved almost simultaneously about 16 years later by Patart in France and a group wofking a t the Badische Anilin- und Sodafabrik. The German group had obtained a patent claiming the use of a mixture of zinc and chromium oxides as a catalyst for this synthesis in 1913, but it is accepted generally that the first workable process was covered by Patart's patent issued in 1921 (2.3). This patent claimed all metals, their oxides and salts, which are known to favoi oxidation or hydrogenation, as catalysts for the reaction. Operating conditions were set at 300" t o 600" C. and 2236 t o 2940 pounds per square inch gage pressure with a hydrogen-carbon monoxide volumg relation of two to one. In spite of Patart's prior discovery it is not surprising that Badische Anilin-und Sodafabrik, having discovered and developed the Haber process ( I ) , should have been able to put the f i s t successful commercial methanol plant on the line in 1923. This plant operated a t 100 atmospheres pressure and 400 'C. and by the end of the year was producing 10 to 20 tons Der dav of Two Converter Vessels Straddled by Gantry Crane, Sterlington Plant synthetic methanol. During the first year of operation the product of this plant was sold, (Right) Furnace used to heat gas during start-up
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2232
i
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 40, No. 12
and 1GO,OOO,OOO gallons per year in the next 3 or 4 years (34). This BASED ON FIRST 6 MONTHS SOURCES estimate, however, does not include aiU.S. T A R I F F COMMISSION lowances for any expansion in formaldeBUREAU OF LABOR STATISTICS hyde production. If present insta,llarU.S. BUREAU O F CENSUS U.S.BUREAU OF FOREIGN B DOMESTIC C O M M E R C E tions for the oxidation of methanol to CHEMICAL FACTS a FIGURES, M C A formaldehyde could operate at full ca0 Ppacity they would consume 45,000,000 gallons of methanol annually. How ever, in 1947 they were able to obtain only about 30,000,000 gallons. Furthermore additional formaldehyde production capacity being constructed this pear is expected to require another 15,000,000 gallons of methanol for raw material per year Capacit)y operation of formaldehyde production facilities is strongly dependent on availability of phenol, a t present still scarce, since the major consumption of formaldehyde is in the manufacture of phenol-foimaldehyde resins. However, the phenol situation is being improved so that it is safe to predict that the formaldehyde producers soon will require an additional 30,000,000 gallons of methanol per year; this brings the total demand for methanol into the area of 200,000,000 gallons annually. I n an attempt to keep pace with this burgeoning demand, methanol production capacity has been essentially doubled since 1945. I n that year production was 77,000,000 gallons (38). In the first 6 months of 1948 nearly 70,000,000 gallons of methanol were produced (81). During this &month period only one of the new postwar plants was in dependable production. By the end 1898 1 9 0 2 1906 1910 1914 1918 1922 1926 1930 1934 1938 1942 1946 of the year most of the postwar expansion program will have been comFigure 1, Production and Price of Methanol Since 1898 pleted. Therefore, i t is safe t o assume that production in the second nounced to have a capacity of about 1,300,000 gallons per year half of 1948 will be substantially greater than that of the first 6 months. I n 1945 only four companies were producing (36), this would set the capacity of the Du Pont plant at about 500,000 gallons per year. methanol synthetically and two of these companies, D u Pont and Since the inception of the process the expansion of production Carbide and Carbon Chemicals Corporation accounted for well over 90% of the production. I n 1946 Celanese Corporation capacity has been rapid and steady. By 1930 the domestic production of synthetic methanol had exceeded that of the natural entered the field with a plant a t Bishop, Tex., where butane and propane are oxidized to the alcohol by a novel process. During product and importation from German producers had receded to negligible proportions. One million gallons of synthetic the past year Solvay Process Company, Spencer Chemical Commethanol were produced in 1927 by the two plants then in pany, and McCarthy Chemical Company also have undertaken methanol synthesis for the first time. I n addition to these new operation. I n 1947 total production amounted to over 80,000,000 gallons (16). entries into the field, the two pioneers in the field both have increased their capacity. D u Pont has constructed a ne& plant at POSTWAR EXPANSION OF CAPACITY Orange, Tex., which it is believed equals the older Belle, I%'. Va., plant in capacity and Commercial Solvents new Sterlinglon Post World War I1 expansion of production capacity has been plant has more than four times the capacity of the company's phenomenal even for this traditionally fast growing industry. Durexpanded unit in Peoria. Three of the new units-those of 801ing the war years the War Production Board limited and eventually vay, Spencer, and Commercial Solvents-are based upon surplus prohibited the use of methanol in automobile antifreeze. Even army ordnance plants. The Solvay and Spencer units have been when relieved of this demand, which normally absorbed beconverted from ammonia to methanol production. The ease of tween 30 and 40% of the total production, methanol production this conversion is partiaUy responsible for the rapid production was unable to keep up with the wartime requirements. Methanol expansion in the postwar period. The Commercial Sohents unit is still scarce and its use in antifreeze has not reassumed its prewar at Bterlington with which this article is primarily concerned WBS volume. It has been estimated that in order t o supply that porbuilt on the site of a partially completed ammonia plant. The big tion of the antifreeze market which used methanol prior to World War 11, production must be expanded to between 134,QQO,OOO enigma of the industry i s the plant built by Du Pont at Morgan-
December 1948
INDUSTRIAL AND ENGINEERING CHEMISTRY
town, W. Va., for army ordnance and operated since the war by Heyden Chemical Company, This plant was built as an ammonia plant, readily convertible to methanol synthesis. During the war it produced both products simultaneously. It is rumored to have a total methanol capacity of between 70,000,000 and 80,000,000 gallons annually or about one half of the present national production. Little methanol has been produced at this plant since the war in spite of the marked excess of demand over the ability to produce. It is possible that other factors make operation of this plant for methanol production impractical. If this plant were to begin operations at capacity the methanol supply picture might be altered overnight. Technologically the most significant recent trend in methanol synthesis has been that from water gas to natural gas as a source of synthesis gas to be fed to the converters. At the end of the war in 1946, 71% of the carbon monoxide used for the synthesis of methanol was obtained from coal or coke. This year an estimated 77% (34) will be derived from reformed natural gas. All but one of the plants built since the war are based on a natural gas feed, and are located in the Southwestern oil and gas field area. Economic considerations primarily are responsibile for the changeover. However, the economic advantage of synthesis from natural gas may prove to be transitory. Within the post World War I1 period natural gas prices, f.0.b. wellhead, have been increased from 1 to 3 cents to 6 to 9 cents. Economic Cassandras have predicted that the climb may go on to as much as 18 cents. At somewhere near this level the coal-natural gas economics may again balance in certain areas where low cost coal is available.
2233
nibaliae therunfinished installation. When Dixie Ordnance Works closed down on the day after V-J Day, little remained of No. 2 unit but the most immovable equipment. The unfinished compressor building remained standing but the gantry crane over the converters had been sold and its supporting structure cut up for scrap iron. The converter shells also had been scrapped. Eleven of the original sixteen compressors remained and the reformer and wasteheat boiler, were partially completed. There was no distillation unit since it was not required for the production of ammonia. CONVERSLON TO METHANOL PRODUCTION
After the cessation of hostilities, the Commercial Solvents operating crew placed the entire plant in stand-by condition. Mechanical units were partially dismantled and all metal pieces given an oil or grease coating. The plant remained in this condition during sales negotiations between the War Assets Administration and Commercial Solvents. I n September 1946 the sales transaction was completed and Commercial Solvents bought the installation as it stood for $5,850,000. It was the original intent of the company to redesign Unit No. 1 so that all or part of it could be employed for methanol synthesis. However, the sustained demand for ammonia as well as the continued scarcity of methanol led compmy officials to expand these plans. No. 1unit continued production as an ammonia plant and the remains of the No. 2 unit warnbuilt into a 45,000-gallon-per-day methanol plant a t a cost of about $5,000,000. This plant went on the line last April and has operated without a major shutdown since that time. As completed, the plant is of conventional modern design which differs little from the first commercial scale methanol synthesis plant built in this country in Peoria by Commercial Solvents in 1927 (36). This original plant was constructed to utilize gases evolved from the butyl alcohol-acetone fermentation chambers. It has been enlarged since and modified to handle natural gas as is done at Sterlington. Temperatures and pressures are essentially the same in both plants. Important changes have been made only in catalyst basket design and in the installation of automatic process controls.
STERLINGTON METHANOL PLANT Of the gas-based installations the easternmost, and hence the closest t o the large marketing centers, is that of Commercial Solvents Corporation at Sterlington, La., on the site of what was once the Dixie Ordnance Works. This plant is built on foundations that were intended for an ammonia synthesiy plant. The reformer furnace, some of the compressors, a few tanks, towers, and partially finished buildings were salvaged from the incomplete ammonia unit. However, the plant cannot be considered as having been converted from the ammonia unit. NATURAL GAS SUPPLY The Dixie ordnance plant was originally authorized, in August The raw gas for the Sterlington plant comes from an area of 1941, to produce 150 tons of ammonia per day. I n March 1942 before the original unit was completed the authorization was inMonroe gas fields within 50 miles of the plant. The gas is creased to 600 tons. Rather than attempt to enlarge the furnished by two suppliers, Southern Carbon Company and partially completed unit or design an additional &()-ton Interstate Natural Gas Company, a t a pipe-line pressure of from unit the construction contractor, The M. W. Kellogg 35 to 50 pounds per square inch. The gas as delivered is largely Company, began the construction of three additional units from the design specification for No. 1. However, 6 months TABLEI. PRESENT PRODUCERS OF SYNTHETIC METHANOL later, in September 1942, the Estimated Capacity, authorization was halved and Millions of Raw Began Gallons per construction on Nos. 3 and 4 Company and Location Method of Production Materials Operation Year" units was halted. Only the Carbide Carbon concrete footings for these units Nia ara Falls, N. Y. CO Hz Coke 1929 (1940)P 6 St. 8 harleston. W. Va CO + Hi GSS 1940 6 were completed. These footCelanese Corporation Bishop, Tex. Oxidation of butane and Gas 1945 4 ings remain unused on the presand propane ent plant site. No. 1 unit was Cities Service Oxidahon of natural gas Gas 1929 (1934)" 6 completed and in production by Tallant, Okla. (CHI) April of 1943. The following COmmerCial SolventB Peoria, Ill. CO + Hz or COS + Ho Gas 1927 (1932)" 3 month authorization for the Sterlington, La. CO + Hz or CO? + HZ Gas 1948 15 partially completed No. 2 unit DuBelle W. Va. co HZ Coke 1927 (1930)'' 32 Gas 1948 32 was canceled and construeHeyden Sabi&Chemical River (Orange), co. Tex. CO + HI tion was suspended. At that Morgantown, W. Va. CO H2 Coke 1943 75 time, No. 2 unit was about McCarthy Winnie Tex CO HI Gas 1948 2 Solvay Piooces8' CO. 80% completed. However, imSouth Point Ohio CO + Hz Coke 1948 11 mediately after construction Spencer C h e m h Co. Military, Kan. CO + Hx Gas 1948 11 ceased the Ordnance DepartBest available estimates give plant capacity based on 330 producing days per year. ment, for whom the plant was b Expanded capacity. being built, began to can-
+
+ + +
2234
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 40, No. 12
0 '
OPERATINGDATAFOR METHANOL PROCESS (Numbers correspond to points on flow sheet, Figure 2) G A S SFREAW
Temperature, Pressuie, O F Lh /Sq.In Gagr
sary with the present gas supply b u t it has beeu iiicluded in the design to provide for the processing of high sulfur gas if it becomes necessary. The sulfur removal drums are divided into four compartments, 6 feet 6 inches in diameter and 28 feet deep, filled with extruded, 0.1875 >( 0.5 inch, cylindrical pellets of zinc oxide. Purification is effected by the reaction: ZnO
7'I 8
1st stage, iu
$1
out 2nd stage, in out 3rd Stage, in out 4th stage, in ?Ut 5th stage, in out
10 11
12 13 14
15 16
17 18
BO 19
21 22 93
s-1
350 940 404 350
5-2 5-3 5-4
30
30 260 30
YO
vi--I W-2
120 264
w-3
w-4
Flue gas t o waste heat boiier Exhaust gas from waste heat boilri
35 1340 600
methane and contains a few objectionable impurities. A typical sample analysis: CH4 CnHr, CrHs
CIH~
2235
INDUSTRIAL AND ENGINEERING CHEMISTRY
December 1948
v/o 93.18
0.55 0.24 0.22
% CSHlY
0.05
con
0.11 0.11
Na
+ HzS
-
ZnS
+ HzO
Four parallel gas paths are available, each passing through two catalyst compartments in series. Two such paths are sufficient to carry the gas flow at normal operating pressureso that ample flexibility is available for clean-out and replacement of adsorbent. The frequency of replacement of adsorbent in these drums will depend on the sulfur content of the gas. With the present supply a t Sterljngton they will probably be active for many years. The purified gas is mixed with 30 pounds per square inch gage steam which has been heated to 940 O F. in a shell and tube heat exchanger which extracts heat from the reformed gas coming from the reformer furnace. The ratio of steam to gas is set by the operator and then maintained automatically by differential pressure flowmeters on both the gas and steam lines. Mixing is accomplished in a sjmple T-joint. The combined gas and steam passes downward in parallel through a bank of 132 catalyst filled tubes arranged in six sections in the reformer furnace. The catalyst used a t Sterlington consists of 0.75-inch ceramic cubes impregnated with finely divided metallic nickel. The fbrnace is gas fired from the top and held a t about 1750" F. The flow of fuel gas to the furnace is controlled by the temperature reading of a thermocouple located in the reformed gas outlet. This outlet temperature is held a t about 1250" C. Flue gas from the reformer is utilized in a waste-heat boiler to produce 40,000 pounds of 260-pound steam per hour. The waste-heat boiler is a watertube type similar in design to the gas-fired boilers in the plant's main power house. The reformed gas passes immediately through the steam superheater where its temperature drops t o about 950 ' F. and then is introduced into a boiler feed water heater where it is cooled to 335" F. Both the superheaters and the feed water heater are shell and tube type heat exchangers. Final cooling of the gases is achieved in R bubble cap io m er oripiiiallv intended as a stripper in
5.54
0 4
Thc gas comes into the plaril through a metering and veductiuii station. The pressure is dropped through a reducing valve in this station to the maximum pressure which can be maintained uniformly. The pressure is usually between 30 and 35 pounds per square inch gage. The reducing valve is actuated automatically based on downstream pressure. Process gas to the reformers is taken directly from this station. Fuel gas for the boiler Furnaces and heaters i s run through a second reducing station where the pressure is further reduced t o 27 pounds per square inch gage. SYNTHESIS GAS PREPARATION
The process gas for the reformer is preheated in a spiral tube gas-fired preheater originally installed as an air preheater for the ammonia unit. The gas enters the unit at the bottom and passeh through one of two parallel, 225-foot, 5-inch outside diameter spiral tubes. The exit temperature is about 750 F. The heated raw gas then is introduced into sulfur removal drums. Commercial Solvents engineers believe that thii purifying step is unnecesO
f-
Flow Sheet for Methanol Process at Commercial Solvents Corporation Plant, Sterlington, La.
Figure 2.
Correction to flow sheet: Total capacity of the two cheok tanka should be 200 000 gallons. Total oapaoity of the two storage tanks should be Z,OOb,OW gallons. Process data at points indioated are given i n tahle top thia page.
Outdoor Pipe Racks, Sterlington Plant Overhead ropper tubes carry gas samples from points throughout plant to analysis lahorntory
VoL 40, No. 12
INBERING CHEMISTRY
thesis from pure carbou monoxide givea about 95% methanol. Mixtnnvl of mono- and dioxide d v vield about 80% ._ methan0L However. Eaution a in more W v exothermic than 4 and fre-
-
__
quently p m x G a imt spots in tie-cata~ystm w . he tampmutum attsined in these hot npota are nu5cieut to initiate the even more highly exoth&c methsnstou reaction whicb reconverta the reformed gaa to methane. Aside from the low of pmduction entailed in this side reaction it in i n c h e d to run away with the pmoeas and sometimes 089 be M t a d only by shutting down thewuverter. Because of these dimdvantapn in the we of the monoxide maction Commercial hlventa, Bince their pioneer inntallstion at PeoriS, bave wed the syntheaia from dioxide. Additional dioxide in the converter feed has a quenching action and affodn a simple means of controlling the speea and temperature of the syntllwin
reaction.
"he mixture of reformed gas and carbou dioxide fmm the w cooler flows to a 1,WO,OO0cubic foot capacity, three-lift gas holder, where it ia held until required by the syntllwin unit. COMPBESSOB CYCLE
A 3O-inob gaa h e leads from the &ss holder into a &inch header which feeds the 6rat stages of the primary compressors The three compressors, arrsnged in parallel, compreea the synthesis gas from bolder pressure to about 4500 poundn per square inch gags in five stnip. They were manufactured by Clark Bmthm and are driven by gayliuder Clark-Skinuer Unifloa
atesm engines developing atw, h.p. The eight nteam cyhdera are mounted vertically in
-
CE+IM)-3E+CO AE + 4 9 , 2 7 1 4 (le)
a &le mw. Compressor cyhdera IUB placed horisontally on both sidw ofthe power c y h d m ; all c y h d m are wnneeted to one cranksbstt. Two first-Btspe and two eacond-stage wmpressor cylinders IUB located on one side and two third-sknge, one fowth-stage, and one fifthon the other. The nteam enginw operata a t 26 inch- of mercury vacuum, maintained by ~U-Raynoldawuntemureut barometric w deneers and two-sbge ejectors with barometric interwndermm. Eaoh compressor ia supplied with intercoolers and knookout dnuns for oil and water, between eacb &age, aud after the fifthstrpe. The intemtage unita ara located outaide the compressor house aa d e t y precautiOn Because of the toxie nature of the carbon monoxide contained in the syntheaia gtu the stuf6ng boxes of the compressom PIP covered by suction hoods conuectad to a MOO-cubic foot per minute onpacity fan vented to the outside atmosphm.
.
(4)
b
1
Daember 1948 wr
INDUSTRIAL A N D ENGINEERING CHEMISTRY
OUrLrT
The compressor house ."ST
rxII~ToI '
which contejns the primary compressors and the circulators is provided with a high capacityventilating systsm to emwe Sgaiaet the building up of
carbon monoxide in the atmaspbere. Eightfsns, each having a cspnaity of l5,OMl cubic feat per minute, force air through the s 0 0 , ~ b i c foot compressor areapmviding nine complete air changea per hour. Thehighpressuregas from the three wmpres-
sora entea a common manitold where it mmbines with reckduting Figlue5. c i m ~ b m ~ gan from the oonvedera and entea the reolouT=P lsting camp-, called circulators. Thefourcirculators am Singlsstap, with two vertical stesm cyLinders, and two horisontal comprwm nyltndeas on one side. Thes? enginas also operate at reduced m;thevaouumnystemellre similar t o ! h for the primary compressora. wIw&IITBLSYSTEM
since the xmvwrtm am estimated to have about ia to 15% per pass convemion eEinieney, new makeyp gan comprises only about 15%of the feed to the reckduting pumps. T w o circulstors operate in padel for each convertersystamto&thegae pressure to the operating level of about 4800 pounds per quare inch gage. Eaoh pair of ciroulatora dinto a common Line which leads to two pardel oil trap which remove the laet traces of nowweow im~uritiesfrom the svnthenia m before it enters the co&rtm. The outlet line fmmthe twooiltraDsof esah c i r & ~ s v s t e m isdividdintoamain feed tathe top the con-, a b;-&to the bottom of the wnvertar, and quench linea which am induced a t variow pointa to permit olose control of conversion tempera-. AU lines am controlled by valva operated from a contmI@ inside the comprassor building. The introduction of cold @ into the catalyst bed for temperatam control ea praotioea a t Sterlington is a common p d m snd is known to have been eonployedin Germen m t h & p h t a Howem, an intardug variation has been reported WM water is injeated into the nyntheain @ stream to control the tempexatum in the convwtor (7). In addition to the localised cooling pvid€d by the quench lines the ovBFd.ll temperature of the converter ahamber be lowered by h c r e w i q the rate of gse Eow and/or demeaains the operating pressure. Themain atream of apnthesb gse from the control station Eows to the top of the converter, downward through the annulsr mace batweun mnverter shell and oatdyst bulket, through the shell side of the converter exchanger, upward through the t u b s imbedded in the cat&%, downward through the catalyst beda, through the t u b side of the,-ni and out the bottom of the converter to a water caaoade condemser. The h a t pass eervea both to 0001 the catalyst bed and to preheat the resotor @. Actuel conversion o m on the thir&pw (9). The Commercislsolvents io8tellation operating at about 5ooo pounds per square inch gage pmmm and 400' C. is a relatively high tempratum and low pressure unit. c-t p d c e in methanol conversion rsngea from aa00 to 14,100 pounds per
sqminchgageand 2.50" to400pC. (I8,cB). In general,per cent conversion vsrke inverealy with the temperature and directly with the pressure. optimum condition8 81'8 reporid to exist in the temperature mnge 800' to 400' C. (SI). Condensed methanol and unrasoted gssea from the after-cooler Eow to a methanol Beparator where separation of the gase% and product methanol in made. Thia separator is eimilar to the oil trap mentioned above. Recycle ges flow8 from the top of the separator drum to the suction of the circulabra. A Statham strain gage and an automati0 variable d c e bleeddff valve am introduced into the recycle Line to maintain a constant pressure in the lim and consequently in the converter. If thera were no purging done at thin point the conmtmtion of nonnurcting &ases in the converter would inBtesdily t h w inorensing the pressure in the converter syntau. The p w p @ coasista of unconverted carbon mono- and diorides and bydmgen 88 well ea uncrackedhydrocarhandnanitrogem. Itisledfmmthepurgevdve tothe power boiler h b o x e a t o t o m t h e fuel potential present. Iiqnid metb.nol pmdunt Eown by meohanidliquid level control to the lewown drnmn from whence it in pumped thmugh positive
d i s p ~ t ~ t o i n ~ t e s t o r s g e t s n k a . OOm~TEE AIJXILLUUES
An external refrigeration system, having a capacity of 130,oOO in provided to condenee the vapors vented from the letdown dnuna Thia ldligemtion unit is unique with the starlington p h t . In northern instellations where cooling water t h p e r a t w a 01ul be maintained around BooF. 80 little oondem ble material pssaes through the after coolers that p d u a t laas However, at Dixie, from the letdown drum vent is m&ihle. oooling water temperutmva often reach 80' F. which does not completely the lower b o i converter products. The pmmnt eaperiment.linatdlation in d-4 to maintain a temperatmeofi35eF.inthevantconde~r. B.t.u. per hour,
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.
2231
CATALYST BASKET
if
INTERCHANOE TUBES
CONVERTER SHELL
(m.
HEAT INTERCHANOER
01s OUT
Fi-6. G-
SohsmPtloDi.gunof
Flow Though MethPnol Syn-
the&
convslw
.
2238
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 40, No. 12
Natural Gas Reformer Furnace, Sterlington Plant Drums a t right m e steam superheater and heat evchangrri vertical drnma in background are sulfur romoral araits
-1 start-up heatei, siniilai I I I tlv.igii to tlir reioiniei ga- piclieatei, is provided for the synthesis a) stcni To bring the coii\ertei catalyst mass up to reacting trinpeiaLure a nonieactnig ga. a t 2500 pounds per squaie inch gage is circulated from the stariup hcater through the pumps, iuto the bottoni and out the top of the catalyst bed. The start-up period for the converter system i.i normally about 48 houis. The reformei cycle can be brought into production from cold iron in about 24 hours. In contrast tlic s j nthesis line can be shut donri in fiom 3 to 4 hours whereas 21 how\ are required before repail- oi change;. can be effected 011 the I + former system. Converter catalyst baskets ale of Coniiiiercial Solverit. Coi poration design and neie built in the shop a t Sterlingtoii. The] are designed so that the) can be lilted fioiii the top of the colirerter shell by the overhead garit r r ci arie \+hick straddles the converter area. When it is i w c e w m to replace or examine r h c catalvst mass the entiie basket 15 iemoved arid placed in a vertical support at the end of the ron of coiiverteis and another loaded baiket is placed in the coiiwrter. This arrangement minimifie5hutdown time a3 well a* providing ea
