Petrochemicals and Biofuel

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gas at Bintulu Malaysia in 1993. • Qatar Petroleum and Sasol built a 35 KB/D GTL plant at Ras Laffan Qatar that started up in 2007. • To date GTL and CTL been ...

Use of Fischer-Tropsch to Convert Gas Coal or Biomass to Crudes

Section 1

FISCHER-TROPSCH SYNTHESIS

History Fischer-Tropsch Synthesis • In 1923, Two German scientists Franz Fischer and Hans Tropsch discovered synthesis gas could be converted into heavier hydrocarbons suitable as synthetic fuels • The Germans used Fischer-Tropsch (F-T) technology during World War II to produce 4.5 Million Barrels of Synthetic oil from coal to fuel the German Army • In 1955 Sasol-I was built by the South African Govt. to product synthetic oil from coal

• Expanded by building Sasol-II and Sasol-III in the 1980s • Current capacity is approximately 160 KB/D of synthetic oil

• Coal based Fischer-Tropsch is proven Technology operated successfully in South Africa for over 50 years

History of Gas-to- Liquids • The South African Govt. built a 12.5 Kb/D plant based on natural gas feed (GTL) at Mossel Bay SA in 1991 • Shell built a 12.5 KB/D GTL plant using natural gas at Bintulu Malaysia in 1993 • Qatar Petroleum and Sasol built a 35 KB/D GTL plant at Ras Laffan Qatar that started up in 2007. • To date GTL and CTL been technical successes with questionable economic viability. • Enormous investment cost is difficult to justify even with very low feed costs

History Fischer-Tropsch Synthesis (cont.) • More recently there has been interest in using operate a large plantBiomass, vegetation or wood chips as feed to F-T gasifier feed. • Small demonstration plants ( CH2 + H2O • Polymerization CH2 + CnH2n => Cn+1 H2n+2 • Termination CnH2n + H2 => CnH2n+2 • The distribution of N-Paraffin products is determined by the relative probability of polymerization instead of termination dfined as a

Fischer-Tropsch Product Distribution • Mechanism is similar to many other Polymer reactions: • Monomer formation: CO + 2H2 => CH2 + H2O • Polymerization CH2 + CnH2n => Cn+1 H2n+2 • Termination CnH2n + H2 => CnH2n+2 • The distribution of N-Paraffin products is determined by the probability that the chain continues to polymerize instead of terminating this probability is defined as a

Fischer-Tropsch Product Distribution • Mechanism is similar to many other Polymer reactions: • Monomer formation: CO + 2H2 => CH2- + H2O • Polymerization CH2-+ CnH2n- => Cn+1 H2n+2• Termination CnH2n- + H2 => CnH2n+2 • The distribution of N-Paraffin products is determined by the probability that the chain continues to polymerize instead of terminating this probability is defined as a • For commercial catalyst a varies between 0.5 and 0.95

Fischer-Tropsch Product Distribution • Described mathematically by the AndersonSchulz-Flory Distribution • PredictsWeight fraction by carbon no: – Wn = (1- a )2 a n-1

Fischer-Tropsch Product Qualities • Product quality depends on catalyst • Cobalt based catatyst primarily produces N-paraffins • Iron based catalyst produces more Oxygenates (primarily alcohols) and Olefins as byproducts.

• Lower temperature and higher activity catalyst tend to produce heavier products (higher a ) • Exceptionally high quality Diesel (80+CN) and Jet product • Naphtha Octane is low but may have high value as petrochemical feedstock • Heavy Wax is excellent FCCU or Lubes plant feed • Often mildly hydrocracked to form diesel • Plants that produce large amounts of light olefins will oligomerize C3/C4 olefins to produce addition diesel.

Fischer Tropsch Process Summary • Fischer –Tropsch (F-T) is a mature technology that has been successfully operated commercially for over 50 years. • The F-T process using synthesis gas ( a combination of Co and H2 ) as a building block to produce high quality synthetic crudes. • F-T feedstock is extremely flexible because any Hydrocarbon can be converting into synthesis gas via partial oxidation or steam reforming reactions • F-T products are a broad range of Hydrocarbons that required additional processing to maximize value.

Section 2

XTL PROCESS CONFIGURATIONS

Fischer-Tropsch Process Configurations • Three Step Process • Syngas Generation • F-T Synthesis • Product Upgrading

• Overall configuration is very similar for gas,coal or biomass feeds. • Syngas generation section must have a gasifier for solid feeds and solids handling facilities for feed and ash. • Conventional Steam Reforming followed by Secondary Reforming is typical for Natural gas feeds • F-T reaction and upgrading is the same independent of feed source – Mild Hydrocracking to maximize diesel is the most common upgrading method.

Typical GTL Process Flow Removed CO2 Air

Air Separation

Naphtha

Light Product HDS

O2

Kero

CO2 removal

F-T Liquid F-T Reaction

Feed Gas

Secondary Reformer

Steam

Primary Reformer

F-T Gas loop

Syn Gas

PSA: H2 removal for Hydroprocessing

Diesel

Vacuum Flash distillation

Liquid Product Separation

Wax hydrocracking

Wax Recycle Main Process Flows Recycles Air and O2

PROPRIETARY INFORMATION

14

Steam Hydrogen

Typical CTL/BTL Process Flow Removed CO2 Air

Air Separation

Naphtha

Light Product HDS

O2

Kero

CO2 removal

F-T Liquid F-T Reaction

Feed Coal/Biomass Gasifier Steam

Autothermal Reformer

F-T Gas loop

Syn Gas

PSA: H2 removal for Hydroprocessing

Diesel

Vacuum Flash distillation

Liquid Product Separation

Wax hydrocracking

Wax Recycle Main Process Flows Recycles Air and O2

PROPRIETARY INFORMATION

15

Steam Hydrogen

Syngas Generation Targets • Cobalt Catalyst – Only CO and H2 react

– All CO2 separated (component splitter) – CO2 recycle to Secondary controlled with “Adjust” to maintain desired H2 / CO ratio (approx 2.1)

• Iron Catalyst- CO2 also reacts

– Water has shift also occurs CO2 + H2  C0 + H2O – Amount removed controlled using Adjust to give Syngas with desired Riblett Ratio (1.0-1.05) • Riblett Ratio = H2 / (2*CO + 3*CO2)

– Some CO2 is removed for Riblett ratio control PROPRIETARY INFORMATION

16

F-T “Gas Loop” Considerations • Syngas conversion at F-T reactors is typically 6080% per pass – Product is flashed and flash gas is recyled – Unconverted Synthesis gas is recycled along with C4produced in the in the F-T reactor. – Small purge to syngas generation to prevent C1-C4 build up in recycle ”gas loop”.

PROPRIETARY INFORMATION

17

F-T “Gas Loop” Considerations • Syngas conversion at F-T reactors is typically 6080% per pass – Product is flashed and flash gas is recyled – Unconverted Synthesis gas is recycled along with C4produced in the in the F-T reactor. – Small purge to syngas generation to prevent C1-C4 build up in recycle ”gas loop”.

PROPRIETARY INFORMATION

18

Integrating F-T Into an existing Refinery • Petroleum coke is gasified to produce Syn Gas – A portion could be used for H2 production or power generation – Remaining Syngas goes to a F-T reactor to produce additional high quality refinery products. – Heavy F-T wax is excellent quality FCCU or HCU feed

PROPRIETARY INFORMATION

19

Integration of CTL into an existing Refinery Low Btu Gas to Refinery

Pet Coke Sweet Syngas

Sour Syngas

Scrubber

Gasifier

F-T Slurry Reactor

Sep Drum

Char and Slag

Purge gas

Naphtha

H2

HCU + Separator Drum

Diesel

Fractionator

Wax

Hydrocracked Wax + Lighter

F-T Liquid to FCC Feed HT Fractionator

Section 3

SYNGAS GENERATION AND PRODUCT UPGRADING

Syngas Generation Process Options • Catalytic Reforming of Natural gas in a Steam Methane Reformer. • Partial Oxidation of Coal/Biomass or Natural Gas • Catyaytic Secondary Reforming or “Autothermal Reforming” of Natural gas and/or Primary Reforming effluent over a fixed bed at 950-1000C • Gasification of Coal or Biomass typically at 1000-1300 C. • Gasification is considerably less reliable than reforming (8085% vs 99%) • Requires spare

• CO2 Removal and operating conditions adjusted to achieve H2/CO ratio or Riblett ratio target

Typical CTL/BTL Process Flow Removed CO2 Air

Air Separation

Naphtha

Light Product HDS

O2

Kero

CO2 removal

F-T Liquid F-T Reaction

Feed Coal/Biomass Gasifier Steam

Autothermal Reformer

F-T Gas loop

Syn Gas

PSA: H2 removal for Hydroprocessing

Diesel

Vacuum Flash distillation

Liquid Product Separation

Wax hydrocracking

Wax Recycle Main Process Flows Recycles Air and O2

PROPRIETARY INFORMATION

23

Steam Hydrogen

Steam Methane Reforming Furnace

Gasification Reactor

Syngas Generation Chemistry • Partial Oxidation Reactions (O2 limited): • CxHy + ½ x O2 => x CO + ½ y H2 • CO + ½ O2 => CO2 • H2 + ½ O2 => H2O • Reforming: CH4+ H2O  3H2+ CO • Equilibrium limited:

Kref = P2(CO)(H2)3 /((CH4)(H20)) • Water gas Shift: CO + H2O  H2 + CO2

Kshift = (CO2)(H2)/((CO)(H20)

Typical CTL/BTL Process Flow Removed CO2 Air

Air Separation

Naphtha

Light Product HDS

O2

Kero

CO2 removal

F-T Liquid F-T Reaction

Feed Coal/Biomass Gasifier Steam

Autothermal Reformer

F-T Gas loop

Syn Gas

PSA: H2 removal for Hydroprocessing

Diesel

Vacuum Flash distillation

Liquid Product Separation

Wax hydrocracking

Wax Recycle Main Process Flows Recycles Air and O2

PROPRIETARY INFORMATION

27

Steam Hydrogen

Product Upgrading Options • Fractionation to recover Naphtha, Jet and Diesel Products: • Diesel and Jet is extremely high quality • Gasoline Octane is low • Naphtha Specialty chemical value may be higher with expensive recovery options like Molex. • F-T wax (heavier than diesel cut) can be converted to high quality diesel in low severity HydroIsom/Hydrocracking reactor • May be more valuable as specialty wax or lubricants but market Is limited

Summary • Fischer-Tropsh is a commercially proven technology that can be used to convert any Hydrocarbon into a high value synthetic crude. • It is a three step process: • Syngas generation • F-T Synthesis • Product Upgrading

• The Diesel and Jet product is extremely high quality • Investment cost is extremely high. • Economics are more attractive than they have been in the past because of low natural gas prices and high crude oil values.

Backup Material

Gasification Reactor

Gasification Reactor

Oxygen Coal Water

Gasification Reactor

Gasification Reactor