gtl mau de e hieu, co gioi thieu hoat dong cua ftr va distilate and hydrocraker nhe

8/12/2019 GTL Mau de e Hieu, Co Gioi Thieu Hoat Dong Cua FTR Va Distilate and Hydrocraker Nhe

1/43

Natural Gas to Liquid Fuels UsingIon-Transport Membrane Technology

Process Design & Profitability Analysis of

Doug Muth, Eve Rodriguez, Christopher SalesFaculty Advisor: Dr. Stuart Churchill

Senior Design Project 2005


2/43

What is Gas-to-Liquids?

Conversion of natural gas to liquid fuels (e.g., diesel).

Gas-to-Liquids (GTL)

SYNGASPRODUCTION

HYDROCRACKING

FISCHER-TROPSCHSYNTHESIS

Diesel

Natural Gas


3/43

Motivations for GTL

Transportation Natural gas reserves are often too far from gas pipelines. Transporting liquid or electricity is more feasible.

Environmental US EPA regulations require reduction of sulfur content. GTL naturally produces extra low-sulfur diesel.

High Fuel Quality High cetane numbers for GTL diesel. Low aromatic and olefin content.


4/43

Design Basis

GTL plant to be located in Ohio.

Minimum DCFRR of 12% required.

Evaluate ion-transport membranetechnology for syngas production.


5/43

GTL Conversion Strategies Direct Conversion of CH

4to Methanol

Too difficult to control. High activation energy required. No suitable catalyst.

Indirect Conversion Via Synthesis Gas Syngas converted to long-chain hydrocarbons by the

Fischer-Tropsch (FT) reaction. Syngas production methods:

1. Steam reforming of methane.2. Dry reforming of methane.3. Partial oxidation of methane.


6/43

Production of Synthesis Gas

Steam reforming of methane.CH4 + H 2O CO + 3H 2 (endothermic)

Dry reforming of methane.CH4 + CO 2 2CO + 2H 2 (endothermic)

Partial oxidation of methane. * CH4 + O 2 CO + 2H 2 (exothermic)

*Optimal H 2/CO ratio (2:1) for FT synthesis.


7/43

Partial Oxidation of Methane

Near ly pur e O 2 requi red for partial oxidation.

O 2 Purification Methods

Cryogenic distillation of air. Hundreds of equilibrium stages required. High energy costs of refrigeration. Substantial capital cost (insulation, compressors, etc).

New Alternative : Oxygen ion-transport membrane. Potentially cheaper than cryogenic air separation plant. Membrane not yet commercialized, cost not known.


8/43

Ion-Transport Membrane

Membrane provides O 2 for syngas production.

CH 4 + H O 2 CO + 3H 2

O 2-

2e -

Natural GasSteam

Syngas Oxygen-Depleted

A ir

A ir Membrane

ReformingCatalyst

Reducingatmosphere Oxidizingatmosphere

CH 4 + 1/2 O 2 CO + 2H 2

OxygenReduction

Catalyst

Courtesy of Air Products, Inc.


9/43

Ion-Transport Membrane Membrane material: non-porous mixed conducting metallic oxides.

Perovskites LaxA1-xCoFe 1-yO3-z

(La = Lanthanides, 0


10/43

GTL Process Overview

GTL process divided into four main parts:1. Convert CH 4 to CO/H 2 with membrane reactor.

CH 4 + 1/2O 2 CO + 2H 2

2. Convert CO/H 2 to synthetic hydrocarbons (Fischer-Tropsch).

nCO + 2n H 2 (-CH 2-)n + H 2O

3. Hydrocrack synthetic hydrocarbons to fuels (mainlydiesel).

4. Separate hydrocracked product into standard oil

fractions.


11/43

GTL Process OverviewNatural Gas

ITM Reactor(Syngas Production)

Syngas

Fischer-TropschSynthesis

Hydrocracking

Synthetic wax

Hydrocracked wax

Fractionation

Tower

HP Steam

Turbine andGenerator

H 2

Heavy Gas Oil

Fuel Gas

Naphtha

KeroseneDiesel

Excess Electricity

1.

2.

3.

4.

Air


12/43

Key Equipment Details

ITM Reactor Fischer-TropschReactor

Hydrocracker Distillation


13/43

ITM Reactor Vessel

Function: Convert methane into synthesis gas.

Design Details: T = 1650 oF, P = 300 psig Horizontal shell/tube reactor. 45,000 ft 2 membrane area required. 2900 membrane tubes (OD = 2 in, L = 30 ft).

Inconel Alloy for shell and tubes. Shell packed with 39,300 lbs nickel/alumina catalyst.

CH4 + O 2 CO + 2H 2

CH4 + H 2O CO + 3H 2


14/43


15/43

Praxair ITM Reactor Model (2003)

ITM MembraneSteam ReformingCatalyst Bed

Syngas Methane & Steam

AirO2-depleted Air

Halvorson et al. (US Patent)


16/43

Entire ITM Section


17/43





18/43

Fischer-Tropsch Reactor

Function: Produce long-chain hydrocarbons from synthesis gas.

Design Details: T = 400 oF, P = 400 psig Slurry volume of 3400 ft 3. 276,000 lbs cobalt/ruthenium catalyst required. Synthesis gas bubbled through bottom.

13 ft diameter ensures proper gas superficial velocity. Dynamic settler separates molten wax from catalyst

particles. Stainless steel construction.

nCO + 2nH2 ( -CH 2-)n + H 2O


19/43

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0 10 20 30 40 50 60 70 80Carbon Number

M o l e / W e i g h t F r a c t i o n

Fischer-Tropsch ProductsAnderson-Schulz-Flory Distribution

Diesel

M{n} = (1 - ) n-1

W{n} = n (1 - )2 n-1

For Co/Ru, = 0.94

Mole Fraction M{n}

Weight Fraction W{n}


20/43

Entire Fischer-Tropsch Section


21/43





22/43

Hydrocracker Reactor

Function: Cracks and isomerizes long-chains to shorter chains.

Design Details:

Molten wax trickles down from top. Hydrogen-rich stream fed through bottom. T = 725 oF, P = 675 psig Height = 27 ft, ID = 9 ft 30,000 lbs catalyst bed (0.6% Pt on alumina). H2/Wax = 0.105 kg H2 / kg wax WHSV = 2 kg wax / hour - kg cat. Stainless steel construction.


23/43

Modeling the HydrocrackerFrom Hydrocracking Kinetic Model

(developed by Pellegrini et al).

Lumped hydrocarbon groups

Hydrocracking reaction pathways

Cracking and isomerization occur.


24/43

Modeling the HydrocrackerFrom Hydrocracking Kinetic Model

(developed by Pellegrini et al).

MW drops along reactor length.

Longer chains crack more quickly.

Isomerization improves cold properties.


25/43

Entire Hydrocracker Section


26/43





27/43

Fractionation Tower

Function: Separates HC effluent into standard oil fractions.

Design Details: P = 10 psig, T condenser = 100 oF, T bottoms = 725 oF

Feed preheated to 725o

F and fed on bottom stage. Steam injected on bottom stage (0.5 lb / bbl bottoms) 16 Koch Flexitrays. 6 ft tray diameter, 2 ft spacing 40 ft height Diesel drawn off at tray 12.

Kerosene drawn off at tray 8. Naphtha & Fuel Gas in overhead. Heavy Gas Oil recycled to hydrocracker Sidedraws eliminate need for multiple towers.


28/43


29/43

Auxiliary Units


30/43

Process Summary

Raw Materials Products Natural Gas 1.95 MM SCFH Diesel 2,700 bbl/day

Kerosene 1,800 bbl/day Naphtha 200 bbl/dayHGO 90 bbl/dayElectricity 10,500 kW


31/43

US Proven Natural Gas Reserves (2003)

For a 15 year plant life, required puddlesize for plant is 0.263 trillion standardcubic feet (TSCF).

1.126 trillion SCF available in Ohio.

U.S. Total: 189 TSCF


32/43

Profitability Analysis Membrane price unknown.

Determine maximum membrane cost that still allows profitability. Criterion: minimum IRR of 12%

Unit ID Description Cost Method Cp, Purchase Cost Bare-Module Factor Total Bare-Module CostC1 Air Compressor Seider et al. $2,228,888.71 2.15 $4,792,110.73C2 Syngas Compressor Seider et al. $1,410,323.09 2.15 $3,032,194.64C3 H2 Rich Compressor Seider et al. $239,837.22 2.15 $515,650.02P1 FT Wax Pump Seider et al. $7,863.98 3.3 $25,951.13P2 FT Wax Pump 2 Seider et al. $7,863.98 3.3 $25,951.13HX1 Air Heat Exchanger Aspen B-JAC $65,000.00 3.17 $206,050.00HX4 Kettle HP Steam Generator Aspen B-JAC $98,500.00 3.17 $312,245.00HX6 Syngas Cooler Aspen B-JAC $21,960.00 3.17 $69,613.20RX1 ITM Syngas Reactor Vessel (without membrane) Seider et al. $417,187.88 4.16 $1,735,501.58RX2 Fischer-Tropsch Reactor Vessel Seider et al. $198,836.93 4.16 $827,161.63RX3 Hydrocracker Reactor Vessel Seider et al. $298,149.10 4.16 $1,240,300.26TB1 Steam Turbine Seider et al. $513,962.10 2.15 $1,105,018.52V1 Water Decanter Seider et al. $85,054.51 3.05 $259,416.26V2 Water Condenser Seider et al. $20,000.00 3.17 $63,400.00T1 Fractionation Tower Vessel Seider et al. $94,922.89 4.16 $394,879.22

Trays Seider et al. $38,745.41 1 $38,745.41Fired Preheater Seider et al. $229,100.83 2.19 $501,730.82

HX5 Overhead Condenser Seider et al. $45,479.00 3.17 $144,168.43Five Tower Pumps Seider et al. $36,193.26 3.3 $119,437.77

V3 Reflux Accumulator Seider et al. $10,000.00 4.16 $41,600.00G1 Electric Generator - $513,962.10 2.15 $1,105,018.52Membrane Ceramic Ion Transport Membrane Not commericalized Financial Variable N/A N/A

Nickel-Alumina Market Price $196,500.00 1 $196,500.00Cobalt Market Price $3,309,919.29 1 $3,309,919.29

Platinum Market Price $2,518,778.30 1 $2,518,778.30

TOTAL $22.6 million


33/43

Variable Cost Summary

Natural gas price trumps other variable costs of operation.


34/43

Assumed Product Prices

Diesel Fuel $1.82/gal* Kerosene $1.24/gal Naphtha $1.00/gal HGO 70/gal Electricity 6/kW-hr

*Assumed 15% higher than typical diesel due to low-sulfur and highcetane number.

Source: US DOE


35/43

Membrane Cost Tolerability

Membrane costs that give IRR = 12% NG cost cannot exceed $6/MSCF.

PROBLEM:

Analysis assume no price correlation

between liquid fuels and natural gas!


36/43

Energy Price Correlation

Hydrocarbon prices historically show correlation.


37/43

Energy Price Correlation

Regression Analysis R = 0.85 Diesel changes 16/gal for every $1/MSCF change in NG.

0.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

1.600

1.800

0 1 2 3 4 5 6 7 8

Natural Gas Price ($/MSCF)

D i e s e l

P r i c e

( $ / g a

l )

ActualPredicted


38/43


39/43

Sample Cash Flow

Assume NG costs $5/MSCF Assume $5 million membrane investment. NPV @ 12% is $59 million.

April, 2005

Year Percentageof DesignCapacity

Sales Capital Costs Working Capital Variable Costs Fixed Costs Depreciation Allowance Depletion Allowance Taxable Income Income TaxCosts Net Earnings Annual CashFlow

Cumulative NetPresent Value

at 12.0%

2005 0.0% Design -$20,039,000 -$10,691,200 -$30,730,200 -$30,730,202006 0.0% Construction -$20,039,000 -$10,691,200 -$30,730,200 -$58,167,902007 45.0% $ 34,291,000 -$14,385,500 -$8,552,900 -$7,156,800 $0 $4,195,800 - $1,552,400 $ 2,643,400 $9,800,200 -$50,352008 67.5% $51,436,400 -$21,578,300 -$8,552,900 -$11,450,900 $0 $9,854,300 -$3,646,100 $6,208,200 $ 17,659,100 -$37,72009 90.0% $ 68,581,900 -$28,771,000 - $8,552,900 - $6,870,500 $0 $24,387,500 -$9,023,400 $15,364,100 $22,234,600 -$23,62010 90.0% $ 68,581,900 -$28,771,000 - $8,552,900 -$4,122,300 $0 $27,135,700 - $10,040,200 $17,095,500 $21,217,800 -$11,62011 90.0% $68,581,900 -$28,771,000 -$8,552,900 - $4,122,300 $0 $27,135,700 -$10,040,200 $17,095,500 $21,217,800 -$862012 90.0% $ 68,581,900 -$28,771,000 - $8,552,900 - $2,061,200 $0 $29,196,800 - $10,802,800 $18,394,000 $20,455,200 $8,382013 90.0% $68,581,900 -$28,771,000 -$8,552,900 $0 $31,258,000 -$11,565,500 $19,692,500 $19,692,500 $16,3402014 90.0% $68,581,900 -$28,771,000 -$8,552,900 $0 $31,258,000 -$11,565,500 $19,692,500 $19,692,500 $23,442015 90.0% $68,581,900 -$28,771,000 -$8,552,900 $0 $31,258,000 -$11,565,500 $19,692,500 $19,692,500 $29,7822016 90.0% $68,581,900 -$28,771,000 -$8,552,900 $0 $31,258,000 -$11,565,500 $19,692,500 $19,692,500 $35,4432017 90.0% $68,581,900 -$28,771,000 -$8,552,900 $0 $31,258,000 -$11,565,500 $19,692,500 $19,692,500 $40,4972018 90.0% $68,581,900 -$28,771,000 -$8,552,900 $0 $31,258,000 -$11,565,500 $19,692,500 $19,692,500 $45,0102019 90.0% $68,581,900 -$28,771,000 -$8,552,900 $0 $31,258,000 -$11,565,500 $19,692,500 $19,692,500 $49,0402020 90.0% $68,581,900 -$28,771,000 -$8,552,900 $0 $31,258,000 -$11,565,500 $19,692,500 $19,692,500 $52,6372021 90.0% $ 68,581,900 $21,382,400 -$28,771,000 - $8,552,900 $0 $31,258,000 - $11,565,500 $19,692,500 $41,074,900 $59,33

Cash Flow SummaryGTL Membrane


40/43

Why not just burn it? Alternative : Burn the natural gas across a gas turbine to create

electricity. Using data from 2001 senior design project Combined-Cycle Power

Generation by Beaver, Matamoros, and Prokopec. 290 MW possibility @ 57% total efficiency.

Total BM cost of plant: $150 million ($22.6 million + membrane) Annual sales: $145 million ($68 million) Total annual costs: $120 million ($38 million) NPV @ 12% is -$118 million ($59 million)

IRR is only 2.7%

Not a competitive alternative!


41/43


42/43

Recommendations

Confirm ITM O 2 flux rate Flux rate of 10 cm 3/cm2-min assumed for design. Current research report values from 0.1 to 20 cm 3/cm2-min. Required membrane area strongly dependent on O 2 flux

rate. Determine ITM stability and durability. Investigate low-sulfur, high cetane diesel price.

Recommend ITM/GTL plant construction

once membrane is commercialized.


43/43

Acknowledgements

Professor Leonard Fabiano Dr. Stuart Churchill

Industrial Consultants Gary Sawyer Peter Schmeidler Adam Brostow

William Retallick David Kolesar Henry Sandler John Wismer

gtl mau de e hieu, co gioi thieu hoat dong cua ftr va distilate and hydrocraker nhe

Documents