PRODUCTION OF FISHER TROPSCH

LIQUID FUEL USING SOLID OXIDE

ELECTROLYSIS CELLS

01.06.2015Neocarbon seminar

Marjut SuomalainenVTT

Introduction

SOEC = Solid oxide electrolyser cellFT = Fisher Tropsch

WHY SOEC

* assuming all energy input is electrical** Steam electrolysis. *** Investment cost estimations are from Mathiesen et al (2013). The lowest SOEC system cost is based on the estimation of SOFC stack cost 175 $/kW in mass manufacturing for annual production volume of 250 MW.

AEL PEM SOEC

Year 2020-2030

2020-2030 2020 2030 2050

Electricity to fuel efficiency* % LHV 50-70 68-72 76.8* 76.8** 76.8**Investment costs (systems) *** M€/MW 0.87 1.27 0.93 0.35 0.28Lifetime system years 25-30 30 10-20 10-20 10-20

Source of the table: Mathiesen et al (2013)

Fischer Tropsch process• Catalytic conversion of synthesis gas (CO + H2) to

aliphatic hydrocarbons

2 + 1 + + 0

• Raw product (crude oil) is separated and upgraded to commercial hydrocarbon liquids like– Diesel– Aviation fuel

• Typically commercial FT plants areextremely large (producing 2500-85 000 bpd) and not economically feasible in small scale

Small scale FT process• Microchannel reactor technology

– Reactor contains microchannels typically in range 0.1 - 10 mm

– Better mass transfer and heat control in the reactor (avoiding the hot spots) compared to traditional FT reactor

– Higher catalytic productivity

Source: LeViness et al 2011 Improved Fisher- Tropsch Economics enabled by Mocrochanneltechnology. White paper, Velosys.

WHY SOEC + Fischer Tropsch

• Syngas (H2 + CO) is required as input for Fisher-Tropsch plant– SOEC is the only electrolyser which produces syngas through co-electrolysis of H2O and

CO2

• Replacement of liquid fuels like diesel high value product

• SOEC has higher electricity to fuel efficiency than other electrolysers

• Synergies: – Potential heat integration of SOEC and FT plant may increase electrical efficiency, if part of

the energy required for SOEC is derived from FT process

TECHNICAL EVALUATION

Next

SOEC – Fisher Tropsch plant

OPERATING CONDITIONSSOEC• Atmospheric pressure, 800 oC• 10 MWe input into electrolyser• Gas composition input

•H2 10 %•CO2 29 %•Steam 61 %

• SOEC •ASR 0.2 cm2, •Reactant utilisation 80 %, •Faradic loss 1 %•Heat loss 2 %

Fisher-Tropsch• Pressure 30 bar• T = 200 oC• Catalyst productivity 1500 kg/m3• CO conversion 72.5 % per pass• = 0.9 • C5+ selectivity 84 %• CH4 selectivity 9 mass%

Upgrading process (hydro-cracking)• 40 bar• 325 oC• Mass ratio of required hydrogen to

hydrocracker feed 1%• Gas make from the process 2 %

PRELIMINARY RESULTS

• Total electricity consumption 11.4 MWe• Electricity to fuel efficiency 52.7 %(LHV)• No heat integration at present

SOEC Co-electrolysis &

FT plant

CO2 (0.74 kg/s)Water (0.64 kg/s)

Electricity (11.4 MWe)

PtL (6.0 MWfuel LHV)

PRELIMINARY RESULTSELECTRICITY CONSUMPTION

• Total electricity consumption 11.4 MWe– SOEC 10.3 MWe– Rectifier loss 0.5 MWe– Other consumption 0.7 MWe

ECONOMICEVALUATION

Next

SOEC investment cost• SOEC stack cost is based on SOFC stack cost (same cells)

– SOFC stack cost is based on two comprehensive studies of estimating SOFC cost in mass manufacturing

• Thjissen (2007) 175 $/kWe (HHV) • James (2012) 200$/kWe (HHV)

• Power density– in SOFC ~0.4-0.5 W/cm2. – in SOEC ~1-2 W/cm2.

SOEC stack cost 50-100 $/kW

• SOEC system cost estimation ~ 200-300 €/kWe

CO2 SOURCE AND COSTFrom solid fuels (coal/biomass) combustion processo ~15 vol-%o Impurities which require

efficient cleaningo Bonus: extra heat available

from the power plant

From biogaso ~35-40 vol-%o Significant impurities which

require efficient cleaningo Bonus: extra heat may be

utilised in digestion plant

From atmosphereo 0.04 vol-%o No significant impurities

From NG combustion processo ~ 5 vol-% o Minor impuritieso Bonus: extra heat available

from the power plant

LOCATIONAND OPERATIONDay-night shiftOnly at cheap electricity (pricelevel below…?)Nominal operation load at lowelectricity price and partialoperation load at high electricitypriceElectricity purchase from the grid or own production

Main considerations related to the location

CO2 sourceAvailablility of heat sink/ sourceElectricityDemand of liquid fuels

Integrating the system to an existing oil refinery or sellingthe syn crude to oil refinery?

Next steps

• Heat integration• Continuation of economic evaluation• Sensitivity to

– Annual operating time– SOEC system cost estimation– FT system cost estimation– Electricity price– CO2 price

EU PROJECTSOPHIA

Other SOEC relatedresearchproject at VTT

SOEC system test station at VTTin EU project SOPHIA

• SOEC system tests will be performed in the EU project SOPHIA (Solar Integrated Pressurized High Temperature Electrolysis)– Partners: VTT, HYGEAR, GDF SUEZ, DLR, SOFCpower, EPFL, HT ceramics,

CEA

• New high temperature electrolyser test station (HELEN) has startedoperation at VTT– SOEC stack from SolidPower– Experimental investigation started on 15th May– Initiation of the stack in SOFC mode

SOEC test stationat VTT Biologinkuja

Furnace

Gas pannel

PLC basedautomation

SOEC stack

THANK YOU!

QUESTIONS?