1995: commissioning/operation of leading concept methanol

Commissioning/Operation ofLeading Concept Methanol Process

The Leading Concept Methanol process has been successfully commissioned and is fully operationalon a commercial basis with production rates 20% higher than design rates. This easy-to-operate

technology is applicable on an offshore floating oil and gas production platform.

P.W. FarnellICI Katalco, Bilingham, Cleveland T523 1 LB, England

Introduction

BHP Petroleum (BHPP) has now successfullycommissioned the 164 mtpd (181 stpd)Methanol Research Plant (MRP) on the out-

skirts of Melbourne, Australia. The plant has been insuccessful operation from the initial commissioning inOctober 1994. The MRP represents the first commer-cialization of ICI Katalco's leading concept methanol(LCM) process which is based on ICI Katalco's gasheated reformer (GHR) technology. The plant is a jointventure between BHP Petroleum and Diamond R&DAustralia, a subsidiary of Mitsubishi Corporation, withBHPP being the plant operator.

BHP Petroleum is a major producer of oil and gas inAustralia with reserves elsewhere in the world. BHPPcurrently operates four offshore oil fields in Australianwaters. Over the past decade BHPP has continuouslydeveloped the technology of oil and gas extraction andprocessing using floating production storage .andoffloading (FPSO) facilities. These facilities are essen-tially oil tanker sized vessels which are moored to the

oil and gas collection risers by a flexible coupling. Theoil and gas processing facilities are located on thedeck of the vessel, and .the stabilized crude oil isstored in below deck tanks. The associated natural gasis flared if the fields are too remote from potentialmarkets for economical utilization. The FPSO is ser-viced by a shuttle tanker which offloads the stabilizedcrude and transports it to the eventual customers.

BHPP has considerable offshore reserves of oil andgas some of which are not as yet being exploited dueto their remoteness. With the associated natural gasnot being economically viable as a gaseous feedstockor fuel, BHPP has been addressing other means ofconversion into a salable product. ICI Katalco's LCMprocess offers such an enabling technology for theconversion of natural gas to methanol on an offshorefloating oil and gas production platform. The majordevelopment over conventional technology whichallows the use of LCM offshore is the GHR and sec-ondary reformer combination for the generation of thesynthesis gas. The GHR/secondary reformer combina-tion is suitable for use offshore due to its insensitivity

AMMONIA TECHNICAL MANUAL 268 1996

Steam Oxygen

Natural ga»

Fuaeloll

leuning columnbotton» (water) * Cruda methanol

* - returned to Saturator

Figure 1. Methanol research plant foundation.

to vessel motion, its structural integrity during vesselmotion, its compact arrangement, and the lack of anopen source of ignition. A standard fired reformerwould not be capable of easy installation in an off-shore environment due to the above considerations.

In order to verify and develop the LCM process foroffshore operation BMP Petroleum first built the MRPas on onshore plant located in the outskirts ofMelbourne. The plant has been designed and built pri-marily for research and development, but is nonethe-less being operated as an economically viable com-mercial plant and is supplying a significant portion ofAustralia's methanol market. The plant capacity of164 mtpd (181 stpd) is small compared to world-scaleplant capacities of 2,000-3,000 mtpd (2,200-3,300stpd). This was chosen based on market size and withregard to the plant's role in proving the LCM technol-ogy before a world-scale plant is designed.

Process Description

A methanol plant can be considered as being formedof 3 distinct processing steps. First, there is the synthe-sis gas generation (SGG) section which is basedaround the steam reforming of the hydrocarbon feed-

stock and the processes associated with that operation.Secondly, there is the methanol synthesis loop, whichis based around the converter. Finally, there is the dis-tillation section where product methanol is recoveredfrom aqueous crude methanol.

The process flow scheme for the whole plant isgiven in Figure 1 and this will be described in moredetail.

Synthesis gas generation section

The hydrocarbon feedstock is natural gas which ispiped from the offshore Australian Bass Strait fieldssoutheast of Melbourne and is available at 19 barg(275 psig). The natural gas is compressed to thereformer operating pressure of 45 barg (650 psig) inreciprocating compressors. The sulfur compounds(mainly odorants) are then removed from the naturalgas in a low-temperature hydro-desulfurization unit.This is based on ICI Katalco's low-temperaturePuraspec absorbents and operates at 230°C (450°F).Purge gas from the methanol synthesis loop is used tohydrogenate the sulfur compounds before absorption.

The natural gas is then saturated in a saturator whichis heated predominantly by the reformed gas exitingthe GHR. The steam ratio exiting the saturator is about2.6, which represents 90% of the total steam require-ment for the reforming reactions. The saturator is alsoused as a means of recycling all of the aqueous wastestreams. Process condensate, refining column bottoms(the water from the crude methanol) and the fusel oil(a small mixed alcohol/water stream) are all recycledto the saturator. The saturator then strips out all of thehydrocarbons from these waste streams and recyclesthem to the reformers. This arrangement minimizesthe amount of final liquid effluent and ensures that theeffluent that is produced has a minimal oxygendemand.

The saturated stream from the saturator is thenmixed with a small amount of process steam whichraises the steam ratio to 2.9. This is a second benefit ofthe configuration of the saturator circuit which mini-mizes the required steam production from the utilityboiler, and hence the demand for boiler feedwater.This is particularly important for an offshore locationwhere all boiler feedwater must be derived from the


desalination of sea water.The natural gas and steam mixture is then preheated

to 425°C (800°F) in a small upshot fired processheater, the GHR preheater. This heater is fired on amixture of natural gas and purge gas from themethanol synthesis loop.

The gas is then passed to the gas heated reformerwhere about 25% of the steam reforming reactions arecarried out. The GHR is similar to those used in ICIKatalco's widely reported leading concept ammonia(LCA) process (Ammonia Technical Manual,1990,1991,1993,1995). The GHR will be described infurther detail in the Section on novel technology.

The partially reformed gas from the GHR is thenpassed on to the secondary reformer which is oxygenfired. In a methanol process there is no requirementfor nitrogen which would reduce the efficiency of theprocess. Air or enriched air are therefore not suitablefor combustion within the secondary reformer. Thesecondary reformer completes the reforming reactionsincreasing the gas temperature to 975°C (1,790°F).This will be described in further detail later.

One advantage of using the GHR and oxygen firedsecondary reformer is that the synthesis gas is stoi-chiometrically balanced for methanol synthesis. Thebalance between the amount of reforming carried outin each of the reformers can be varied to ensure thatthis is the case as the natural gas composition varies.

In order that the GHR/secondary reformer combina-tion can be started up, a small catalytic combustionunit is incorporated between the two units, which isknown as the startup igniter. This unit catalyticallycombusts and reforms a low-temperature mixture ofnatural gas, steam, and air to provide a stream of hotsynthesis gas to start up the secondary reformer.

The gas from the secondary reformer then passesthrough the shellside of the GHR, heating the tubesidewhere the reforming reactions occur. The gas exitingthe GHR shellside is then further cooled by providingheat for the saturator circuit and distillation. Finalcooling is provided by a cooling water exchanger andthe process condensate is then removed.

Methanol synthesis loop

The cooled synthesis gas is then compressed up to

70 barg (1,015 psig) in a second reciprocating com-pressor and passed into the synthesis loop. The synthe-sis loop consists of a gas circulator, heat interchangersand heat recovery, the methanol converter, and productcooling and separation. The methanol converter is ofthe tube cooled design as used successfully in a num-ber of methanol plants using the ICI low-pressuremethanol process.

Overall, the design of the methanol synthesis loop isstandard as used in many other methanol plants.

Distillation

The crude methanol produced in the methanol syn-thesis loop is an aqueous solution containing about80% methanol by weight. It also contains trace quanti-ties of higher alcohols and other byproducts synthe-sized on the synthesis catalyst. A two column distilla-tion system is required, with the first column, the top-ping column removing the light fractions from theaqueous solution. The second column, the refiningcolumn, which is the main column, separates the waterfrom the methanol, and in addition removes a smallthird stream containing the higher alcohols from thecenter of the column.

Novel Technology

Gas heated reformer

The GHR is essentially the same as that used in ICIKatalco's LCA ammonia process albeit, on a smallerscale. The major change is in the reforming sectionheat and mass balance which is different for the LCMprocess. In the LCA process the oxidant used in thesecondary reformer is air, and the nitrogen contributesabout 50% of the total shellside mass flow in theGHR. As in all reformers, the heat input into theprocess gas within the tubes is a combination of bothsensible heat and the heat of reaction. In the LCAprocess with a shellside mass flow of twice the tube-side mass flow there is a more balanced heat transferbetween the two sides of the GHR. In the LCMprocess where pure oxygen is used, the mass flow onthe tubeside and the mass flow on the shellside areapproximately the same, which gives a different ther-


mal balance in the GHR. In order to ensure that theGHR was optimally designed for the LCM plant con-ditions the balance of heat transfer had to be reopti-mised by changing tube dimensions.

The tube design philosophy from the LCA GHR isretained, in that finned double pipes are used toenhance the shellside heat transfer, and the insulatedbayonet tubes are used to remove the process gas fromthe bottom of the catalyst tubes. This is illustrated inFigure 2, which shows the tube arrangement.Additionally, the metallurgy of the GHR is the same asthat used in the LCA GHR which has now beendemonstrated to be resistant to corrosion over manyyears.

Secondary reformer

Early on in the development of the LCM process,the secondary reformer was seen as the major techni-cal risk. Oxygen fired secondary reformers have amixed record in the synthesis gas industries (AmmoniaTechnical Manual, 1994, 1995) and against this back-

Methane andsteam

Cartridge

Hot secondarygas

Primary effluent

Cooled secondarygas exit

Scabbard Tube

Primary catalyst

Fin

Sheath Tube

Bayonet Tube

Refractory

Figure 2. Gas heated reformer.

Oxygen inlet

Refractory

Catalyst —

Gas fromGHR tubes

Gas toGHR shell

Figure 3. Secondary reformers.

ground a substantial amount of design effort wasinvolved in verifying the burner and combustionchamber design. Computational fluid dynamics (CFD)was the chosen technique for ensuring that the designwas acceptable. CFD, a fluid flow modeling and simu-lation technique which can be used to model sec-ondary reformers has been covered in great detail inprevious articles (Ammonia Technical Manual, 1994,1995).

ICI Katalco's design of a secondary reformer isbased on a design used in 8 of Id's world-wideammonia plants over the past 20 years with great suc-cess. The Katalco design uses the neck region of thesecondary reformer as the combustion zone, awayfrom the catalyst bed as illustrated in Figure 3. Themixing of the oxidant and the process gas is more easi-ly controlled in this region where the presence of thecatalyst bed cannot disturb the flow patterns. Thedesign of the ICI Katalco burner ensures that at anypoint in the combustion zone, the temperature of thegas in contact with the refractory is as low as possible.Additionally, it is possible to achieve near perfect mix-ing of the two streams before the gas reaches the cata-lyst bed. The design is simple and easily scaled up to


Gas + Steamintet

RefractoryLining

CombustionCatalyst

ReformingCatalyst

Figure 4. Startup igniter.

very large plants sizes, with experience up to 1,500mtpd ammonia (1,650 stpd).

Startup igniter

The purpose of the startup igniter is to produce ahydrogen containing gas stream which is above itsautoignition temperature with no external high-tem-perature heat source. The startup igniter is very similarto an ICI Katalco designed secondary reformer and isshown in Figure 4. The startup igniter is a develop-ment of the unit used in the LCA ammonia plantswhich has been simplified based on further develop-ments of the technology.

The feeds are a mixture of natural gas, steam and airwhich are combined in a mixing region. However,unlike a secondary reformer the mixed feed is too coldto combust and passes down to the catalyst bed. Thetop section of the catalyst bed is a low-temperaturecombustion catalyst which burns the natural gas withthe oxygen in the air. The lower section of the catalystbed is a reforming catalyst which aids the productionof hydrogen. The gas then flows into the secondaryreformer which can then be ignited spontaneously by

admitting the oxygen feed.The startup igniter requires the addition of a com-

bustion initiator which combusts at low-temperature.The temperature is raised by combustion of the initia-tor which then leads to ignition of the natural gas. Theinitial plant design included bottled hydrogen supplyfor this use since this was a proven initiator from theoperation of the LCA plants.

Distillation columns

Since the MRP is being used to prove the offshoretechnology, the distillation columns utilize structuredpacking rather than the traditional plates. Wheninstalled offshore, the distillation columns must beable to perform while the production platform rockswith the sea swell. Trayed columns would not performwell with variable liquid levels over the trays.Structured packing is much less affected by the rock-ing motion since it relies on surface tension to keepthe packing wetted. This is the first application ofstructured packing to the distillation of crude methanolin an ICI licensed process.

Commissioning and Initial Operation

Commissioning period

The plant was handed over to the BHPP OperationsGroup after final mechanical completion at the end ofAugust 1994. The commissioning team includedBHPP operations personnel with support from ICIKatalco and Davy Process Technology.

The first month of the commissioning period wastaken up with the completion of precommissioningactivities. This included the startup of the utilities andoff-sites including the demin plant, the package boiler,cooling water, etc. Within the on-sites area, the maincompressors were inspected, the compressor controland trip systems proved and the units commissioned.

A fully functional test of the process trip system wascarried out during this period as was a full checkthrough the DCS control loops and logic sequences.Upon completion of this period, all items of rotatingmachinery has been proven functional as has the con-trol systems.


At the end of the precommissioning period, the low-temperature Puraspec hydrogénation catalyst in thedesulfurization system was activated with a mixture ofnatural gas and hydrogen from a bulk trailer. After thisactivation, the decision was made to reduce themethanol synthesis catalyst with bottled hydrogenbefore the synthesis gas generation section was startedup. Despite the additional expenditure, with the novelreforming section it was believed that this providedthe safest and most reliable method of reducing thiscatalyst.

In early October the SGG section was commissionedfollowing a predetermined procedure. There was ini-tially a period of nitrogen circulation followed bynitrogen and steam circulation for several days. Thisallowed testing and tuning of control loops on-line andthe commissioning of the fired heater upstream of theGHR.

The reformers were first started up on the October15th and the plant rate settled out at 50% of design.The synthesis gas was flared at this point and con-troller tuning was completed over the following 1-1/2days.

First, methanol was produced on October 17th aftertwo attempts to start up the synthesis loop due to con-trol instabilities on the circulators. The plant then ranfor a period between 50% and 100% rate. During thefinal week of October, the plant ran steadily with noproblems at 100% of design rate for 7 days, provingthe process design of the plant.

Initial operation

In early November, problems developed in the start-up heater in the synthesis loop requiring the plant to beshut down for a short period of time. The seal systemson the natural gas compressors developed high leak-age rates requiring reduced rate operation for severaldays. These issues were rectified in early Decemberduring the planned shutdown for the secondaryreformer burner gun inspection (see secondaryreformer subsection). Upon restart, the plant rate wasincreased to 105% of design and stabilized at this ratewith no process limitations evident.

The major plant limitation is the oxygen availabilitywhich is supplied "over the fence" from a local air

separation plant. A period of increased oxygen avail-ability was negotiated which allowed a series of highrate trials to be undertaken. During these trials the ratewas increased over a 3 day period with plant ratesfrom 115 to 122% of design being achieved. Refinedmethanol product rates of 200 mtpd (220 stpd) wereachieved without any impact upon product quality.

Following these plant trials, the plant was returnedto operation at 105% of design. Since December theplant has run consistently at rates between 95% and105%, limited mainly by oxygen availability.

During the initial operating period there was a high-er than expected rate of plant trips. These trips weresplit equally between electrical power disturbances,package boiler control and instrumentation, and theusual number of trips associated with the startup of anew plant. After each trip, the underlying reasons wereestablished and action taken to prevent further occur-rences due to that problem. This approach of continu-ous improvement has been very successful with thetrip rate falling to more acceptable levels. It is a fea-ture of the GHR/secondary reformer combination thatit can quickly recover from plant trips and therefore isa more robust design than conventional reforming.

Saturator

There have been no problems with the saturator andits associated heat recovery circuit. Initial data fromthe plant shows that the stripping efficiency of the sat-urator for methanol and higher alcohols is very good.This is evident from the fact that before the plant oper-ation was optimized, the water feeds to the saturatorcontained higher than design quantities of organics,yet the small blowdown from the saturator containedbelow design levels of organics.

A small modification was carried out to the saturatorcircuit after 4 months of operation which eliminatedsome bypassing of organics directly to the blowdownand effluent system. The efficiency of the strippinghas now been enhanced and the organics content ofthe blowdown is now zero, indicating total removal ofall organics. This performance significantly reducesthe effluent treatment costs associated with this plantcompared to a conventional plant.


GHR

The GHR has operated well from the first startup.Detailed analyses of the GHR performance has shownit to be performing slightly better than design in termsof both catalyst activity and heat-transfer efficiency.These analyses have revealed a number of interestingfeatures:

(1) The heat loss through the refractory lining is lessthan allowed for in the design. This leads to a greaterrecovery of heat in the GHR and in the saturator heatrecovery system. This has two impacts upon the plant:first, less oxygen is required in the secondary reformeras the GHR is more efficient; secondly, less additionalsteam is required from the package boiler to achievethe required steam ratio, reducing gas consumption.

(2) There is evidence that the shift reaction is occur-ring on the shellside of the GHR. This has beenobserved as an increased level of CO^ in me synthesisgas fed to the loop, and corresponds to a shift equilib-rium temperature about 100°C (180°F) below the sec-ondary reformer exit temperature. The process appearsto be kinetically controlled as the extent of the shiftreaction is dependent upon the plant rate. This effect isnot of concern to the reforming section.

Secondary reformer

The process performance of the secondary reformerhas matched the design condition for the reformer withan approach to equilibrium of essentially zero. Theheat loss through the refractory lining is lower thandesign; hence, the reformer is more efficient andrequires a lower oxygen feed. Therefore, less syngas isburned internally in the secondary reformer leading toa higher overall process efficiency.

Since this is the first application of the ICI Katalcodesign of secondary reformer burner with pure oxy-gen, the burner was removed after 1 week, 5 weeks,and 4 months of operation to prove that the burner wasnot suffering from erosion or cracking. At each inspec-tion, the burner was found to be in pristine condition.An indication of the condition of the burner nozzle isthe continued presence of the original surface marksfrom the machining of the nozzle during fabrication.Any wear of the nozzle would have removed these

fine surface marks. The burner will continue to beoperated for longer periods between inspections. Thenext inspection will occur at an appropriate date afterapproximately one year of accumulated operation. It isexpected that these inspections will confirm that theburner has a life expectancy comparable to thoseachieved by the ICI Katalco burner in air duty, whichis in excess of 10 years.

During the burner gun inspection after 4 months on-line, the secondary reformer was entered and inspectedinternally. The refractory surface was in "as new" con-dition except for a slight glazing of the surface due tothe normal temperatures encountered in oxygen firedsecondary reformers. There was no loss of refractorythickness nor any spalling or melting of the refractorysurface.

Startup igniter

The startup igniter has proven to be extremely robustas it has now operated in excess of its design life dueto the high number of startups during commissioning.The catalyst activity within the unit is still higher thandesign with a lower approach to equilibrium thanexpected. There has been some wetting of the catalystdue to condensate collection in the inlet pipe whichhas resulted in minor catalyst spalling, but this has notaffected catalyst strength or activity.

Test work has shown that the hydrogen used to initi-ate combustion is only required for about 10-15 min.Once the catalyst bed temperature rises, the catalyticcombustion of the methane becomes self-supporting.Additional plant trials have identified that methanol isalso a suitable combustion initiator which combustscatalytically at low temperatures. This is obviously ofbenefit to a methanol plant since the need for thehydrogen bottle facility is eliminated. The plant is tobe converted to methanol for this duty and all futureplants will use this technique.

Distillation columns

The distillation section has produced on specifica-tion product right from the first methanol produced.The dynamics of the packed columns are significantlydifferent when compared to conventional trayed


columns due to the small liquid holdup. This leads torapid temperature and composition changes within thecolumns, which has required the use of improved con-trol methods that were not originally incorporated inthe design.

There is one minor problem in the refining columnin the section below the feed point. The compositionand temperature profiles within this section of packingindicate that the separation should be good but themethanol content in the water is higher than design.This inconsistency indicates that there is probably amaldistribution problem. Currently, this is not a prob-lem on the plant since the bottoms water is recycled tothe saturator and all of the organics are stripped outthere. Furthermore, the quantities are too small toimpact on the plant efficiency or production rates.

Plant performance

Plant performance data is taken daily by BHPP fromsnapshots of the DCS data which are downloaded intoa separate database. These snapshots are shared withICI Katalco so that both companies can continue tomonitor the performance of this new technology.

Figure 5 shows the achieved natural gas efficiencyof the plant. This graph shows three levels of energyconsumption which fall as the time on-line increases.Early data show high values because the fuel systemhad not been fully commissioned and purge gas fromthe loop was being flared. Data over the next 3 monthsshow a lower energy consumption as the fuel gas sys-tem was commissioned and the plant operation wassettled out at high rates. The more recent data showthat the energy consumption has now fallen further asthe plant operation has become optimized, especiallyin the heat recovery systems and in the steam balance.

There have been some small negative effects uponthe plant efficiency, the main aspect of which is thatthe heat recovery from the synthesis loop into the satu-rator is lower than design. This is due to the circula-tion rate in the loop being higher and the converterrunning cooler. This does have the benefit of a slightlyhigher methanol production and a lower rate of cata-lyst deactivation, but does require extra steam to beraised in the boiler. The small fired heater upstream ofthe GHR is less efficient than design, requiring more

36

^350*34

f 33

E 32

g 31oU 30

I 29

| 28

27

•

*

Design

50 100 150Days on Line

200 250

Figure 5. Natural gas feed and fuel efficiency.

fuel to be burned, leading to a higher stack tempera-ture. The high process efficiency when combined withthe small effects listed earlier gives an overall energyusage slightly lower than the design basis. Furtherreductions in energy consumption are expected as theplant is further optimized and the sources of ineffi-ciency are eliminated.

Conclusion

BMP Petroleum's Methanol Research Plant utilizingICI Katalco's leading concept methanol process hasbeen successfully commissioned. The plant is nowfully operational and producing on specification prod-uct on a commercial basis. The plant is capable of pro-duction rates at least 20% higher than design rates andhas been operated reliably at these rates.

LCM is a logical development of the technologyused in the LCA ammonia process. There has beenconsiderable learning gained from the LCA plants'op-eration which has been incorporated into the BHPPplant design. The proof of this is the very short com-missioning period, taking less than 1 week to achievedesign production rates, and the lack of serious


process related problems. There has been furtherlearning from the startup and initial operation whichwill further enhance future designs of GHR based syn-thesis gas technology.

The information that has become available duringthe early operating phase of the MRP has shown thatthe LCM technology is applicable on an offshorefloating oil and gas production platform. The ease ofthe commissioning and the subsequent operation hasprovided a great deal of confidence in the process andthe technology. BMP Petroleum can now commencethe development of the next phase of the project, alarge scale offshore methanol production plant utiliz-ing the ICI Katalco LCM process.

Acknowledgment

The author wishes to thank BMP Petroleum for sup-plying ICI Katalco with the data contained in the arti-cle. The author wishes to acknowledge the supportgiven by I. Rees and S.G. Sinclair of BMP Petroleumin reviewing the article.

Literature Cited

Armitage P.M., K.J. Elkins, D. Kitchen, and A. Pinto,Leading Concept Ammonia Process: The First TwoYears," Ammonia Technical Manual, Vol. 32,AIChE, New York (1992).

Barton I.R. and K.J. Elkins, "Operational Performanceof Id's LCA Process," Vol. 35, Ammonia TechnicalManual, AIChE, New York (1994).

Blanchard, K.L., and J.R. LeBlanc, "Application ofCombustion Chambers hi Secondary Reformers,"Ammonia Technical Manual, Vol. 35, AIChE, NewYork (1994).

Christensen T.S., I. Dybkjaer, L. Hansen, and I.Primdahl, "Burners for Secondary and AutothermalReforming-Design and Industrial Performance,"Ammonia Technical Manual, Vol. 35, AIChE, NewYork (1995).

Elkins K.J, A.J. Gow, D. Kitchen, A. Pinto,Development & Operation of the Leading ConceptAmmonia (LCA) Technology," The FertiliserSociety, (October 1992).

Farneil P.W., "Secondary Reforming: Theory andApplication," Ammonia Technical Manual, Vol. 34,AIChE, New York (1993).

Hicks, T.C., M.J.S. Moss, and A. Pinto, "OperationalFlexibility of the ICI LCA Process," AmmoniaTechnical Manual, Vol. 30, AIChE, New York(1990).

Shaw G, H. de Wet and F. Hohmann, "Commissioningof the World's Largest Oxygen Blown SecondaryReformers," Ammonia Technical Manual, Vol. 35,AIChE, New York (1995).

DISCUSSIONW. D. Verduijn, Kemira: You touched briefly on thesubject of trip rate. Could you elaborate a little onthat? I realize that you described a plant in the earlyphase of development, but could you give some harderfigures?Farnell: During initial commissioning, we had prob-lems with the electrical supply to the site. Themethanol research plant is located in a light industrialsuburb of Melbourne. The electricity supply was notof a quality required for a continuous 24-hour a dayprocess operation, so we may suffer two/three electri-cal power outages a month, which is quite significant.There has been some work on the power systems. We

installed latching relays that will hold the major elec-trical drives on-line throughout a small transientpower disturbance, and now we're down to trip ratesof one or two per month. We plan to add a secondfeeder to the site to increase the power reliability evenfurther. A further issue that has occurred is that theoxygen plant up the road is on a different feeder sys-tem, and they have their electrical power outages aswell, however, not at the same time as the methanolplant. This has led to a lot of problems that we expectto resolve.Brent Heimann, Arcadian: In your article you men-tioned that you made a modification to the gas


saturator in order to eliminate organics in the blow-down. Can you expand on that?Farnell: Initially, one of the liquid streams returningto the saturator entered the saturator circuit before theblowdown location. Hence, some of the organics weredirectly blown down before they were stripped. Thesmall modification was to relocate the liquid wastereturn point on the other side of the blowdown point,so that all organics pass through the saturator beforereaching the blowdown point.Ross Murdoch, Moss Gas: You indicate that you planto install a 2,000 ton/d per day on a barge. Could youexplain to us how you plan to supply the oxygen forthe secondary reformer?

Farnell: This is one of the major process considera-tions, and there are several avenues we are followingup on in partnership with B HP Petroleum. At themoment, if you will allow me, I'd rather not answerthat question.Max Appl, BASF (Retired): How do you ignite yourinitiator? Do you ignite it electrically?Farnell: The startup ignitor has a low-temperaturecombustion catalyst. We actually light that off by spik-ing in either a small amount of methanol or hydrogen,which will burn at room temperature. Once the cata-lyst is hot, methane will burn spontaneously over thecatalyst.


1995: commissioning/operation of leading concept methanol

Documents