Small Scale GTL (STG Plus) Plant


Course: Regular Fog Modeing Technology (ENCH 609, Winter 2017)


GTL: Synfog to Fogoline (STG Plus)

Professor: Dr. Nashaat Nassar


List of rushures and tables:

  • Rush 1. Schematic draw of the STG+ plan (from Primus Green Courage TM) .. (6)
  • Rush 2. Sensitivity Decombination restraint instance 62.5 MMSCFD (14)
  • Table 1. Economic Indicators restraint scheme evaluation (Detail circumspection in Appendix).. (15)


  • Rush 1. Untrammelled GTL inserts on the earth map [The Ease & Fog Year, 2015] . (21)
  • Rush 2. Airs issue chart patent clear restraint the scheme (from Aspen plus V 7.2 & Microsoft Visio 2010) (22)
  • Table 1: Amendiond compounds and Estimates of consents restraint reactor 4 in the design …. (19-20)
  • Table 2: Economic Evaluation restraint instance 1: 10 MMSCFD ..(23)
  • Table 3: Economic Evaluation restraint Instance 2: 62.45 MMSCFD (24)
  • Table 4: Majority estimate of tides 1-22 restraint Instance 1: 10 MMSCFD ………….(25-26)
  • Table 5: Majority estimate of tides 1-22 restraint Instance 2: 62.45 MMSCFD .. (27-28)


The earth’s courage claim is growing exponentially and to as this claim, bringing innovating contribute fountains to the communicate is exceedingly censorious. Regular fog media are tolerant, geographically sepatrounce and currently to-boot the cleanest meaninguring fossil fuel. Fog to Smooths (GTL) is a chemical mode that transforms regular fog or other fogeous hydrocarbons into tfull description smooth effects that would incorrectly be manufactured from undigested ease [Shell Global]. GTL creates an appended opening to monetize a country’s contrivance of regular fog by turning them into tfull description smooth fuels. GTL effects are pure and odorcork hydrocarbons with very mean smooth of impurities.

The resolve of this scheme is to counterfeit a fine flake GTL (STG Plus) insert that transforms 10 MMSCFD of abundant-methane regular fog into 672 BBL/day of fogoline. The principal stride of the STG Plus mode is named “fume reforming” and it stops of the reaction among the methane in the regular fog with abundant introduce. The remedy stride of the mode is the reaction among the hydrogen, and the carbon monoxide conceding methanol. The methanol thus restraintmed get be transformed to dimethyl ether (DME) and latestly, the DME get be dehydrated, conceding fogoline. The scheme get to-boot talllight the destruction among couple deep GTL technologies: Fischer Tropsch and STG Plus. An economic evaluation was conducted to inhibit the viability of this mode and at 10 MMSCFD interimpute of methane; the scheme proves to be economically advantageous, with an NPV estimate of $14.66M at 10% discount trounce. It was to-boot attached that if the origination of fogoline extensions to aggravate 4,100BBL/day, the availability of this scheme get extension tellingly.

1.0. Introduction

1.1. GTL Technology and the Earth

Gasoline to Smooth (GTL) is a technology that transforms regular fog or other fogeous hydrocarbons into tfull description smooth effects enjoy fogoline or diesel fuel, incorrectly manufactured from undigested ease []. GTL effects are pure and odorcork hydrocarbons with very mean smooth of impurities. Refineries can to-boot amendion GTL to transardispose some of their fogeous hydrocarbon squander effects into estimable fuel ease which can be amendiond to genetrounce fullowance.

The earth’s principal commercial GTL insert was opened by Shell in Bintulu, Malaysia in 1993. In 2011, the largest GTL insert, Pearl GTL was opened in Qatar [Shell Global]. Rushure 1 in the Appendix shows full untrammelled GTL inserts and their similar locations on the earth map.

1.2. GTL Origin

In 1920’s, when Gerdivers disesteemed itself concise of petroleum excluding with roomy reserves of coal, GTL and Coal-to-Liquids (CTL) technologies were pioneered using a mode public as Fischer-Tropsch (F-T) union (Heng et al. 2004). Methanol-to-gasoline (MTG), Mobil’s synthetic fogoline mode, urban on the interimpute of methanol to hydrocarbons using zeolite catalysts, was the principal deep synfuel mode effect in half a date gsingle the effect of the Fischer-Tropsch mode (Freabundant J. Keil, 1998).

1.3. Fog-to-Smooth (GTL) technology

Fog to Smooths (GTL) is a refinery mode that transforms fog or other fogeous hydrocarbons into effects with longer carbon chains. Fogoline and diesel fuel are fashionable samples. Foges with a tfull strain of methane are transformed into smooth synthetic fuels coercionthcoming couple arrangements: plain interimpute – using modees extraneously the intercourse of catalysts that transardispose methane to methanol or by using synfog as a midway effect, such as in the Fischer Tropsch, Synfog to Fogoline Plus and Mobil modees.

This scheme get convergence on sly a fine flake Synfog to Fogoline (STG) plus insert that amendions methane abundant regular fog as recbalance and transforms it to tfull description fogoline and other effects.

2.0. Syngas-to-Gasoline plus (STG+) mode

STG+ mode was acquired from the MTG (Methanol-to-Gasoline) mode, which was patent clear by Mobil in the 1970’s. This technology plainly transforms regular fog-acquired synfog into drop-in fogoline and jet fuel through a catalytic thermo-chemical single-loop mode that minimizes complication, betters effect description and consent. The “plus” in STG+ stands restraint the scruple meaning effects consented by the mode.

The STG+ technology is currently untrammelled by Primus Green Courage community in Hillsborough, Innovating Jersey at pre-commercial flake with a origination of 100,000 gallons (approximately) of unlike description fogoline per year from regular fog with surpassed invadeprise of the STG+ plan and catalyst and 720 hours of rectilineal action. The STG+ mode stops of the coercionthcoming untrammelled strides in single rectilineal mode loop. It comprises of Synfog breed by fume reforming arrangement, indelicate urban bed reactors in rotation and a couple side separator.

Figure 1: Schematic draw of the STG+ plan (from Primus Green Courage TM)

2.1. Synfog Breed by Fume reforming arrangement

The principal stride in the STG+ mode is to transardispose the regular fog recbalance into synfog or union fog which is an intervening fog recbalance restraint divers irrelative petrochemical modees. This modeing basically removes contaminants, such as mercaptans, sulfides, mercury and any others that can settle the contrariant catalysts’ invadeprise that are amendiond in the STG+ reactors antecedently it is nurse to the synfog breed individual. Either civilitying oxidation or fume reforming modees are amendiond restraint synfog origination.

Fume reforming mode is widely amendiond to genetrounce synfog restraint recoverstock in irrelative petrochemical modees. A compound of hydrogen, carbon monoxide, carbon dioxide, and uncivilized methane and fume are restraintmed when methane reacts with fume in the intercourse of a catalyst such as Nickel or Rhodium at tfull sky (800-1000 C), tfull swing (20-40 rests) and fume-to-carbon affinity varying among 1.8 and 4 in the fume reforming mode which is tallly meaningothermic in structure (Mbodji et al., 2012).

The potential reactions are:

  • The fume methane reforming reaction (SMR)

CH4 + H2O ⇄ CO + 3H2 [ΔH = +206 kJ mol-1] (strongly meaningothermic).. (1)

  • The introduce-fog remove (WGS)

CO + H2O ⇄ CO2 + H2 [ΔH = -41 kJ mol-1] (moderately exothermic) . (2)

The effect from the reformer depends on the untrammelled swing & sky, compound of the recbalance fog, and the relation of fume nurse to the reactor. The thermodynamics and kinetics of the reaction among the reformer decides the whole of carbon monoxide in the latest effect from the fume reformer (Larminie & Dicks, 2000).

2.2. Reactor 1 (Methanol Union)

Centrifugal summarizeors are amendiond to summarize the synfog from reforming individual which invades the reactor 1 containing copper zinc as catalyst and the coercionthcoming reaction occurs.

  • 2H2 + CO ⇄ CH3OH [ΔH = -92 kJ mol-1] .. (3)

Imputable to the exothermic structure of the reactions, mean skys civility interimpute to methanol and pre-heating of the reactant fog and ignoringioning of the boiler recbalance introduce are dsingle by this redundancy ignoringion. The supporture of the makeweight depends on the swing and sky. The methanol restraintmation is civilityed by extension in swing.

2.3. Reactor 2 (Dimethyl Ether (DME) Union)

Succeeding the undigested methanol from reactor 1 is preheated, vaporized and then superaffectionate among 300-320oC in a rotation of ignoringion exchangers, it is then sent to the dimethyl ether (DME) reactor containing a dehydration catalyst (alumina) where methanol is civilityingly dehydrated to an makeweight compound of DME, introduce and methanol which is a revocable and exothermic reaction.

  • 2CH3OH ⇄ CH3OCH3 + H2O . (4)

2.4. Reactor 3 (Gasoline Union)

In reactor 3, in intercourse of catalyst the effect fog from reactor 2 transforms to hydrocarbons including paraffins (alkanes), aromatics, naphthene (cycloalkanes) and olefins (alkenes), primarily from C6 to C10.

2.5. Reactor 4 (Gasoline Combination)  

To enjoy tfull octane reckon restraint synthetic fogoline and valuable dimensionstric adaptedties, the effect from reactor 3 is treated in reactor 4 to classify the durene (tetra methylbenzene), Iso durene and tri methylbenzene factors which enjoy tfull freezing points.

2.6. Separator

Finally, in the reactor 4 couple or three side dissociation is dsingle to get synthetic fogoline interposed of paraffins, aromatics and naphthene, non-condensed fog and introduce. The non-condensed fog is recycled end to the recbalance tide restraint reactor 1 and introduce is recycled end to the Fume Reformer (Synfog Breed Individual).

3.0. Why STG+?

The preceding kreferable under obligation restraint GTL amendiond the ordinary GTL technology named Fisher Tropsh (FT) in their airs mode. Fischer-Tropsch (FT), which is a technology patent clear in advenient 1920s, transforms fog into smooth hydrocarbons primarily diesel through a very obscure mode. Conjuncture there enjoy been telling betterments on the teachableness and technology of the Fisher-Tropsch mode, the tgrease is in an importunate demand of innovating technologies prime of transforming as ample fog as potential into smooth fuels in a cheaper and further causatively deportment. As effect, we governmentd to employ restraint our scheme the innovating mode named STG+ patent clear by Primus Courage. The deep effect of STG+ is fogoline as irrelative to diesel. Gsingle the most claimed smooth fuel in Canada, specially in Alberta, is fog, we governmentd referable amendion FT or any innovating technology conceding diesel. STG+ has vaporous advantages aggravate the ordinary GTL techniques such as: meaner untrammelled and high absorbs, taller origination, better effect description and faster delivery times. The “rival” technology of STG+ is ExxonMobil’s MTG mode. However, ExxonMobil’s MTG mode has a ocean environmental impression and it is referable very absorb-effective. STG+ mode was adapted to amend some inefficiencies in the ExxonMobil mode . The deep amendion is the integration of the reactors in a single-loop that extensions the origination and consents a taller description of the fogoline with a cork environmental impression A guide exroomy is integration of the reactors in the STG+ mode.

4.0. Scheme Design/Simulation

4.1. Issuechart Description

The lists of factors that are regarded in the airs restraint the STG+ mode and the consents in majority disesteemed restraint the indelicateth reactor (Keil, 2012) are shown in the Appendix (Table 1). The issuechart patent clear restraint the STG+ mode is shown in the rush. 2 of Appendix.

A dirty interpretation of the issuechart get be dsingle now. Principal, our recoverstock is basically the regular fog. Restraint simplification resolves, our recbalance of regular fog is basically methane. Another recoverstock that this mode get enjoy is untarnished introduce. The introduce get be ignoringioned in a ignoringion exchanger (HE-01) and get be qualified with the methane to invade the principal reactor (R-01). In this reactor, carbon monoxide, carbon dioxide and hydrogen get be manufactured, as explained aggravatehead. The fractional interimpute in the principal reaction is 83.4% of the methane, the limiting reactant. The interimpute in the remedy reaction is 6% of the carbon monoxide (Choudhary et al, 1992). The departure tide of the reactor R-01 is cooled in a ignoringion exchanger (HE-02), invades a summarizeor (CP-01) to extension the swing restraint the remedy reaction mode and, latestly, invades another ignoringion exchanger (HE-03) to prescribe the sky restraint the spiritual sky in reactor R-02. The untrammelled provisions of this reactor are 69 rest and 380°C (Wood et al, 2012). In it, basically, the synfog get be consumed to restraintm methanol. The fractional interimpute of this reaction is 63.7% of carbon monoxide (Lebarbier et al, 2012).

The departure tide of reactor R-02 get ignoring through a ignoringion exchanger (HE-04) to prescribe the sky of the compound to invade reactor R-03. The methanol get restraintm dimethyl ether (DME) and introduce. The untrammelled provisions of this reactor are 12 rest and 325°C (Wood et al, 2012). The fractional interimpute of the methanol restraint this mode is 76% (Kasaie et al, 2010).

The tide that succeedings quenched of reactor R-03 ignoringes through a ignoringion exchanger (HE-05) to classify its sky and then invades a smooth-vapor glister vessel (FV-01). The dimethyl ether along with the non-polar factors get succeeding quenched in the fog tide, conjuncture the introduce get succeeding quenched in the floor or smooth tide, which can be sent to the copious combination insert. The fog tide get ignoring through a summarizeor (CP-02) and then through a ignoringion exchanger (HE-06) to prescribe the sky and swing restraint the indelicateth reaction mode in reactor R-04. Basically, in this reactor, the dimethyl ether get be dehydrated in dispose to rupture down its atom into “-C2H4-” radicals, which get be completely to restraintm largeger atoms, as explained aggravatehead. Gsingle the reaction mode is obscure and the reckon of reactions is large, the stoichiometry of the mode get be very involved. Therefore, this paper singly shows the consent in majority reason of each factor restraintmed in reactor R-04 (consent per individual majority of aggregate recbalance of factors that are referable listed as inerts) (Aspentech Support Technology, 2001). Gsingle singly the dimethyl ether (DME) is a reactant in reactor R-04, full of the other compounds that invade reactor R-04 are regarded inerts.

The departure tide of reactor R-04 get ignoring through a summarizeor (CP-03) and through a ignoringion exchanger (HE-07) to prescribe the swing and sky restraint the patent clear glister vessel (FV-02). This glister vessel is a smooth-liquid-vapor separator that get sepatrounce on the head the fog and lightest effects. The intermediate smooth tide get be the fogoline restraintmed (deep tide) and the floor smooth tide get be the introduce that was restraintmed in the reactor R-04 and must be removed. The fog tide can be sancient to an tgrease that modees fog side hydrocarbons, conjuncture the introduce removed can be sent to the copious combination insert.

4.2. Thermodynamic Design and Airs Regardations

The airs of the STG+ mode was patent clear in the software Aspen Plus® rendering 7.2. In our airs, we chose the GRAYSON design, becaamendment it was patent clear restraint plans stoping of hydrocarbons, such as carbon dioxide and hydrogen sulfide. This arrangement should restable cheerful-tempered-tempered results restraint skys in the dispose of 60°F to 800°F and swings up to 3000 psia (Aspentech Support Technology, 2001). Gsingle our mode contains hydrogen and full the skys of the tides are among this sky dispose, we can amendion the GRAYSON design (Aspentech Support Technology, 2001).

The principal three reactors (R-01, R-02 and R-03) were adapted in Aspen Plus as RSTOIC reactors gsingle singly fractional intercharges and stoichiometry were regarded restraint them. The patent clear reactor (R-04) was adapted as an RYIELD reactor. In this design, the input basis that is required stops of the quenchedlet sky and swing of the reactor, as polite as the consent estimates restraint the factors that are effects of the reaction mode.

4.3. Assumptions adopted in the airs

  • Regular fog recbalance stops singly of methane;
  • We amendiond singly glister drums to perardispose the dissociation of the factors succeeding the reactions.
  • The fogoline consents singly stop of paraffins, olefins, aromatics and cyclic hydrocarbons from C2 to C11.
  • Fractional intercharges and stoichiometry are singly regarded restraint the principal three reactors and no kinetic parameters restraint the reaction modees and catalyst deactivation are regarded imputable to withdrawal of basis.
  • Even though the STG+ mode is polite public restraint the loop which defines the teachableness of the mode, imputable to withdrawal of basis on fractional intercharges restraint C2-C11 compounds, we restricted our airs tend fogoline origination and adapted to dispose-of our effect (Gasoline and Regular Fog) to the other parties who are in impute of any support combination required.
  • Gsingle we are referable including the durene/Isodurene in our quenchedput, the Fogoline combination reactor is referable regarded.

5.0. Economic Evaluation

In dispose to evaluate the economics of the scheme, a coin issue decombination is made urban on the coercionthcoming regardations:

  • Our interest design regard buying treated regular fog to be amendiond as twain recoverstock and fuel fog (we don’t stable royalties becaamendment we are referable conceding it), stableing restraint electricity decrease; and revenues succeeding from fogoline and regular fog sales.
  • Couple years restraint view and 20 years of actions.
  • 340 days of origination per year.
  • Decombination in uniform American dollars of January 2017, exchange trounce of 1.30 CAD to USD.
  • Annual non-fuel untrammelled and deeptenance absorb suitent to 3.6% (Haro P. et al ,2013) of aggregate high consumes.
  • Corpotrounce fullowance rebuke trounce suitent to 28%.
  • Electricity decrease, fuel fog required, issue trounces (recbalance and effects) from the airs design.
  • Current consumes restraint fogoline, regular fog and electricity in Alberta, graspn from Alberta Courage websites.
  • High Absorb Fullowance (CCA) with a half year government is regarded restraint rebuke circumspection resolve according to Alberta congress.
  • Discount trounce 10%.

High consume (CAPEX) restraint synfog breed is estimated using rushures restraint a public insert (Yang & Ogden, 2005) and the coercionthcoming equation to grasp into sumity the irrelative capacities.

…. (5)


Cx = high absorb restraint a insert of largeness x (Sx), Cb = high absorb of the public insert of largeness b (Sb).

CAPEX fullied to the STG+ mode itself is estimated urban on the affinity absorbed by Primus Green Courage (community proprietary of the STG+ technology) that synfog breed typically represents 60% of aggregate high absorb restraint commercial-flake insert and the STG+ mode itself represents the other 40%.

Couple flakes are regarded: 10 MMSCFD of regular fog in the recbalance restraint similitude resolve with the preceding year’s kreferable and 62.5 MMSCFD of regular fog in the recbalance to evaluate the swing of the flake on the economic indicators.

The economic indicators of the scheme are summarized in the coercionthcoming table:

Recbalance Fog Issue trounces (MMSCFD)



Net Present Estimate – NPV @10% (darling $)



Internal Trounce of Restable – IRR



Avail to Investment Affinity – PIR



Breakeven consume restraint Fogoline (CAD/L)



Table 1: Economic Indicators restraint scheme evaluation (Detail circumspection in Appendix)

Finally, a sensitivity decombination is made to visit the swing of irrelative shiftings: regular fog consume, electricity consume, fogoline consume and high absorb on the NPV of the scheme. Restraint these, full shiftings are progressive +10% and -10% and the NPV are fitted. Results shown in the rush. 2 suit to the instance with 62.5 MMSCFD in the recover. However, it is the identical trmeaning in twain instances:

Figure 2: Sensitivity Decombination restraint instance 62.5 MMSCFD

It can be concluded that the scheme is economically possible and the shifting that impression the most the economics of the scheme is the fogoline consume.

6.0. Adviseations

  • We recommmeaning regarding the fractional intercharges restraint C2-C11 compounds in reactor 1 to enjoy a better delineate of STG+ with its cork loop mode.
  • A thoroughgoinggoing compound decombination restraint fogoline in the indelicateth reactor gives further realistic results.
  • There is ample room to extmeaning our tgrease by adding fogoline combination and motive post (instead of glister drum restraint further causative dissociation) with adapted chemical reactions and stoichiometric fractional intercharges and kinetics to better the communicate estimate of our effect.
  • There is possibility restraint regarding further factors in the recbalance fog tend C5-C6.
  • In our design, imputable to withdrawal of basis, we convergenceed on chemical reactions and stoichiometric fractional intercharges. There is room restraint further causative sly by toiling on catalyst cycle vitality.

7.0. Quittance

The 21st date is witnessing the whole of a innovating global interest urban on regular fog modeing. As a effect, the fog-to-liquids (GTL) tgrease is fit increasingly influential as it is getting further unmanageable to meet and quote innovating ease reserves as polite as the intercourse of further environmental restraints. This is why we governmentd to employ the innovating STG+ mode technology in our scheme to demonsttrounce its teachableness in the interimpute of methane to fogoline. As precedingly orderly, we governmentd to dissent from the preceding kreferable mode, primarily becaamendment its technology is ancient and their effect is diesel as irrelative to STG+ mode which is a innovating technology and its effect nature fogoline, which is further claimed in Canada. We chose to do the airs of a fine flake GTL insert that modees 10 MMSCFD of methane, conceding 672 bbld, which resulted in an economically viable mode. The economic indicators showed that, by increasing the origination of fogoline, the avail would extension tellingly (proven with the instance 0f 62.5 MMSCFD). In quittance, STG+ command be really auspicious and advantageous in Alberta if there is a veritable fountain of regular fog and cheerful-tempered-tempered communicate provisions.

8.0. References

  • Alberta courage website. Accessed on March 16th, 2017.
  • Alberta courage website. Accessed on March 16th, 2017.
  • Aspentech Support Technology, Inc.; “Aspen Physical Adaptedty Plan 11.1”; Cambridge, MA, September 2001.
  • Choudhary V. R., Rajput A. M., Prabhakar B; “Mean sky oxidative interimpute of methane to synfog aggravate NiO-CaO catalyst”; Chemical Engineering Division; National Chemical Laboratory, India, May 1992.
  • Haro P, Trippe F, Stahl R, Henabundant E. “Bio-synfog to fogoline and olefins via DME: A general Techno-economic assessment”; Apple Courage; 2013; dimensions 108; page no.: 54-65.
  • Heng H.C., Idrus. S; “The advenient of fog to smooths as a fog monetization option”; Journal of Regular Fog Chemistry 13, 2004; pages 63-70.
  • . Accessed on March 16th, 2017.
  • Kasaie M., Sohrabi M.; “Kinetic Study on Methanol Dehydration to Dimethyl Ether Employing Clinoptilolite Zeolite as the Reaction Catalyst”; Chemical Engineering Department, Amirkabir University of Technology, Tehran, Iran, January 2010.
  • Keil, Freabundant J.; “Methanol-to-hydrocarbons: mode technology”; Department of Chemical Engineering, Technical University of Hamburg-Harburg, Hamburg, Germany, July 1998; page 49.
  • Larminie, James, Dicks, Andrew; “Fuel Cell Plans Explained”; West Sussex, U.K.: John Wiley & Sons; 2000.
  • Lebarbier V. M., Dagle R. A., Kovarik L., Adarme J. A. L., King D. L., Palo D. R.; “Union of methanol and dimethyl ether from synfog aggravate Pd/ZnO/Al2O3 catalysts”; Abundantland, USA, June 2012.
  • Mbodji M., Commenge J.M., Falk L., Di Marco, Rossignol F., Prost L., Valentin S., Joly R., Del-Gallo P. “Fume methane reforming reaction mode intensification by using a milli structured reactor: Experimental setup and design validation restraint global kinetic reaction trounce estimation”, Chemical Engineering Journal, vol. 207-208, pages 871-884.
  • Primus Green Courage website (, Accessed in March 2017.
  • Shell Global Website (, Accessed March 05, 2017.
  • Wood, David A., Nwaoha C., Towler, Brian F; “Gas-to-liquids (GTL): A retrospect of an tgrease aid diverse routes restraint monetizing regular fog”; Journal of Regular Fog Science and Engineering, Dimensions 9, November 2012.
  • Yang, Christopher; & Ogden, Joan M. (2005).”Analyzing Regular Fog Urban Hydrogen Infrastructure – Optimizing Transitions from Distributed to Centralized H2 Origination”; Institute of Transportation Studies; UC Davis.

9.0. Appendix

Factor in Aspen Plus®

Factor name


Majority consent










Carbon monoxide




Carbon dioxide








Dimethyl ether






















































































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