Mitsubishi Heavy Industries Technical Review Vol. 59 No. 4 (December 2022)
1Demonstration Activity of the Bio-Jet Fuel Contributingfor the Carbon Neutrality in the Aviation Industry
YASUHIRO YAMAUCHI*1 KATSUHIKO SHINODA*2TAKATOSHI YAMASHITA*3 ICHITARO TANABE*4

YASUHIKO KOJIMA*5

TAKUYA MIZUNO*6Having set the target limit increase of CO2 emissions after 2021 for the decarbonization ofthe aviation industry, the International Civil Aviation Organization (ICAO) proposes, as the mainmeasures, the introduction and spread of sustainable aviation fuel (SAF). SAF includes the bio-jetfuel (BJF) produced by biomass gasification technology combined with Fischer-Tropsch (FT)
synthesis. Between 2017 and 2021, Mitsubishi Heavy Industries, Ltd. (MHI), in collaboration withJERA Co., Inc. (JERA), Toyo Engineering Corporation (TOYO) and Japan Aerospace Exploration
Agency (JAXA), built a pilot plant for the biomass gasification and FT synthesis process to produce
BJF and conduct combustion and engine tests. The produced BJF was used in a flight by Japan
Airlines (JAL). Our biomass gasification technology is an energy conversion technology that plays
a part in energy transition. Using this technology, we will provide solutions for decarbonization in
the aviation industry.

|1. Introduction
In relation to aviation fuel, the development of hydrogen, ammonia and electric aircraft areunder way as alternatives to fossil-derived jet fuel (kerosene). However, none of these have yetfound their way to commercialization. Especially when it comes to long-haul flights, there are, asyet, no alternatives to jet fuel. In the aircraft industry, with a view to not increasing CO2 emissions
after 2021, ICAO, a United Nations specialized agency, has laid out the Carbon Offsetting andReduction Scheme for International Aviation (CORSIA) until 2035. In order to fulfill the goals,
SAF is expected to be indispensable as one of the key measures in addition to improving theefficiency of flight control and introducing new equipment. Neat SAF refers to the fuel produced
from plant-derived feedstocks, animal oils and captured CO2 with electrolytic hydrogen using
renewable electricity. When blended with Jet A-1 fuel, it is called SAF. Neat SAF is a fuel thatenables sustainable energy circulation of CO2 generated by combustion. As Neat SAF, what iscurrently being tested for practical application is one synthesized from oils or alcohols and one
produced by FT synthesis using syngas produced by gasification of plants.
Since around the end of the 1990s, we have worked on the development of gasification
technology that is pivotal to the carbon-neutral thermochemical conversion of biomass.
Commissioned by the New Energy and Industrial Technology Development Organization (NEDO),
we conducted a joint research project with JERA, TOYO and JAXA from 2017 until 2021. A pilot
facility for the gasification and FT synthesis process using woody feedstock was built on thepremises of JERA’s Shin-Nagoya Thermal Power Station, to demonstrate the viability of integrated
BJF production from wood. The produced BJF was used in a JAL commercial flight from Haneda*1

Authority of Technology, Boiler Engineering Department, Steam Power Maintenance Innovation Business Division, EnergyTransition & Power Headquarters, Energy Systems, Mitsubishi Heavy Industries, Ltd.

*2MHI Executive Experts Co, Ltd.

*3

Deputy Director, Boiler Engineering Department, Steam Power Maintenance Innovation Business Division, Energy Transition &*4Senior Manager, New Business Creation Unit, Domestic Business Development Group, Domestic Business Management &*5Senior Manager, Process Engineering Division, Toyo Engineering Corporation*6Associate Senior Researcher, Environmentally Sustainable Engine Team, Aviation Environmental Sustainability Innovation Hub,Power Headquarters, Energy Systems, Mitsubishi Heavy Industries, Ltd.
Development Division, JERA Co., Inc.

Aeronautical Technology Directorate, Japan Aerospace Exploration Agency

Mitsubishi Heavy Industries Technical Review Vol. 59 No. 4 (December 2022)
2to Shin-Chitose in June 2021. This report describes this project, focusing on the use of BJF as wellas our energy transition technology based on biomass gasification.

|2. Features of the biomass gasification and FT synthesis plant
2.1

Features of the gasifier

Sustainable feedstock is needed to produce sustainable BJF. Forest resources can besustainable when afforestation is appropriately managed and the cut timber is proportional to theamount of growth. The gasification and FT synthesis process, which is shown in Figure 1, is a BJF
synthesis technology using such woody biomass. The key lies in the gasification technology toproduce syngas that enables stable and highly efficient FT synthesis. As shown in Figure 2, there
are three types of gasification depending on the mode of solid-gas (powder-gas) multiphase flow:
fixed bed, fluidized bed and entrained bed. Fixed bed and fluidized bed are advantageous in termsof handling of biomass, as 20-30mm chips can be used in these types. Fluidized bed is favorable
when using high-moisture biomass, thanks to its large thermal capacity. On the other hand, biomass
gasification has the issue of tar production. Less tar is produced with higher temperatures, althoughhigher temperatures increase the risk of clinker formation from biomass ash. Entrained bed is ofuse in this regard because, in this type of gasification, solids are less likely to make contact witheach other, thereby reducing the clinker formation risk. The advantage is enhanced when thetemperature of gasification is elevated, as this results in less production of tar. As described so far,the preferable conditions for biomass handling and gasification stability are at odds with each other,which makes it difficult to simultaneously bring out the best in both of them.

Figure 1

BJF production by gasification and FT synthesis

Figure 2

Solid-gas multiphase flow technology for gasification

An entrained bed gasifier is employed in our coal gasification technology. However, as alock hopper system is used to feed pulverized coal into a pressurized gasifier, blockage prevention

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is needed by pulverizing coal to a particle diameter/shape achieving high fluidity. Because of it
being fibrous, biomass generally has poor grindability and therefore needs a lot of power to grind it
into fine particles, if required as in the case of coal. For this reason, we have developed anentrained bed gasification technology in which relatively rough pulverization to a diameter of about
10 mm can suffice. As shown in Figure 3, the structure of the gasifier was designed in such a way
as to ensure the retention times required for both large and fine particles in the gasifier, whereby
gasification can be performed successfully. In this way, less power is required for grinding
biomass, while the advantage of a high gasification temperature can be maintained.

Figure 3

2.2

Features of entrained-flow gasifier for biomass

Pilot testing of bio-jet fuel production system

During the project period between 2017 and 2021, we built a pilot plant to perform theintegrated production from biomass to jet fuel, in which this gasification technology was used in
combination with TOYO’s FT synthesis system based on Velocys’s proprietary FT technology
shown in Figure 4. The produced fuel was used in a commercial flight.

Figure 4

Overview of FT synthesis system

Mitsubishi Heavy Industries Technical Review Vol. 59 No. 4 (December 2022)
4Verification testing using the pilot plant was conducted under the organizational structure
shown in Figure 5. Built on the premises of JERA’s Shin-Nagoya Thermal Power Station, the pilot
plant had a biomass processing capacity of 0.7 tons/day shown in Figure 6. We were responsible
for the gasification facility, while TOYO was responsible for the FT synthesis system. The
produced bio-jet fuel was tested by JAXA for its combustion and engine characteristics.
The gasification facility achieved 3,079 hours of operation, while the FT synthesis systemachieved 1,543 hours of operation including 30 days of continuous operation exclusively by JERA
operators. The production of reformate totaled 4,233 liters, of which Neat BJF amounted to 2,366
liters and satisfied the ASTM standard requirements. Thus, this pilot testing is considered to havesuccessfully demonstrated the viability of the process(1).

Figure 5

Organizational structure for pilot plant research project

Figure 6

Pilot plant facilities

The combustion characteristics of the produced fuel were assessed under the conditions inwhich the blending ratio with the conventional JET A-1 fuel varies from 0% to 100%. As shown in
Figure 7, the results indicate that the combustion characteristics such as exhaust gas component arecomparable to those of JET A-1. Especially because of the low content of aromatic hydrocarbons,the formation of particle matter (PM) is greatly less than JET A-1. Thus, the superiority of BJF isalso indicated from a viewpoint of PM reduction measures. Although it was not possible to test on
a turbofan engine because of the coronavirus pandemic, the performance was measured using amodel turbojet engine by Kochi University of Technology. The results have also confirmed that
there is no difference between our BJF and JET A-1 in terms of performance, specifically including
thrust, intake air flow, thrust specific fuel consumption rate, and exhaust gas temperature(2).

Mitsubishi Heavy Industries Technical Review Vol. 59 No. 4 (December 2022)
5Figure 7

2.3

SAF combustion characteristics testing

Application in commercial flight

Of the produced BJF, 283 liters was blended with JET A-1 at an oil company’s plant, and2,195 liters was used as a SAF drop-in fuel for the JAL 515 flight from Tokyo/Haneda toShin-Chitose on June 17, 2021. We proceeded with this application, while ascertaining that boththe Neat SAF and the JET A-1 blended SAF met the ASTM standards. The blending ratio was 3%,
which was made public by a press release of the Japanese Ministry of Land, Infrastructure,
Transport and Tourism(3). This was the world’s first commercial aircraft flight in which bio-jet fuelproduced from woody biomass using an integrated production system was used. Thus, a series ofprocesses from the bio-jet fuel production to the fueling of aircraft, which are shown in Figure 8,
have been demonstrated.

Figure 8

Series of processes from bio-jet fuel production to fueling of aircraft|3. SAF standards and certification
The SAF standards are set out in ASTM D7566, which prescribes in its Annexes thepermissible feedstocks and production methods, and the upper limit of blending ratio withconventional jet fuel for each of the production methods. Adopting a new production method
requires approval from the ASTM Standards Committee. The gasification and FT synthesis process
is a technology already registered in Annex 1, in which blending of up to 50% is allowed. Table 1
lists the approved technologies as of 2020(4).

Mitsubishi Heavy Industries Technical Review Vol. 59 No. 4 (December 2022)
6Table 1

Annexes of the ASTM D7566 standards (as of 2020)

Annex
Annex 1

Conversion process
Blending ratio
Fischer-Tropsch hydroprocessed synthesized paraffinic kerosene (FT-SPK)
Up to 50%
Synthesized paraffinic kerosene from hydroprocessed esters and fatty acids
Annex 2Up to 50%
(Bio-SPK or HEFA)
Annex 3Synthesized iso-paraffins from hydroprocessed fermented sugars (SIP)
Up to 10%Synthesized kerosene with aromatics derived by alkylation of light
Annex 4Up to 50%
aromatics from non-petroleum sources (SPK/A)
Annex 5
Alcohol to jet synthetic paraffinic kerosene (ATJ/SPK)
Up to 50%
Annex 6
Catalytic hydrothermolysis jet fuel (CHJ)
Up to 50%
Synthesized paraffinic kerosene from hydrocarbon hydroprocessed esters
Annex 7Up to 10%and fatty acids (HC-HEFA SPK)
Source: MANUAL FOR PROPER HANDLING OF SUSTAINABLE AVIATION FUEL (SAF) ISSUE 1,
Aug. 2021 by the Aviation Fuel Expert Committee of the Petroleum Association of Japan,

To be used for CORSIA, SAF should be produced in compliance with the criteria that prove
the produced SAF is a CORSIA eligible fuel (CEF). The production process is to be reviewed andapproved by a third-party certification organization. CEF can be classified as SAF or low carbon
aviation fuel (LCAF). In either case, CEF has to meet the CORSIA sustainability criteria, which
demand, for validation, the assessment on a life cycle basis including indirect land use change
associated with fuel production, require the achievement of net greenhouse gas emission reductionsof at least 10% compared to the level of fossil fuel, and specify that biomass obtained from landwith high carbon stock should not be used. The land with high carbon stock pertains to the land thatwas primeval forest, wetlands or peat lands and was converted after January 1, 2008. If land use
was indeed converted after January 1, 2008, the Intergovernmental Panel on Climate Change(IPCC) land categories should be used to calculate the induced land use change (ILUC) emissions;the result will be added to the emissions associated with production (core lifecycle assessment orCore LCA). In the LCA of CEF, an ICAO default value may be used, or an actual value may becalculated following the ICAO methodologies. Figure 9 shows some examples of the default
values for LCA of CEF(5). The default value of the gasification and FT synthesis process (asindicated by FTJ in the figure) is lower than other production methods.

Figure 9Examples of default values for ICA of CEF

At present, there are two certifying authorities with standards: the International Sustainabilityand Carbon Certification (ISCC) and the Roundtable on Sustainable Biomaterials (RSB). Thesetwo certifying authorities have their own recognized certification organizations, which review thethird-party certification organizations and accordingly accredit them for handling a certification

Mitsubishi Heavy Industries Technical Review Vol. 59 No. 4 (December 2022)
7(6)(7)process. The certification is based on chain of custody (CoC) standards. The CoC certificate
ensures transparency throughout the supply chain including feedstock’s point of origin, collection,processing and traders and, at each transaction point along the supply chain, assures that theISCC/RSB-certified products were made from the feedstock procured from the certified producers.
The CoC standards basically requires having a management system that meets the requirements
prescribed by the CoC standards, checking up on the suppliers registered on the ISCC/RSBcertificate, checking on the transactional documents and the quantities of traded products,
confirming the traceability, and having product identification and labeling systems. Producers
seeking certification need to submit the application form to a third-party certification organization
for a contract and be examined via internal audit to prove that the requirements set by the standards
are satisfied.

|4. Energy transition by biomass gasification
In gasification and FT synthesis, by-products such as diesel oil, naphtha and LPG areobtained in addition to bio-jet fuel. These by-products are also green fuels derived from biomass.
For example, the quality of naphtha is high enough to be suitable for chemical synthesis, and it canbe used as a raw material to produce plastics. Moreover, if captured, the CO2 generated in theproduction process, which is of course derived from biomass, can be expected to be a new sourceof domestic CO2 supply, as the mergers and closures of domestic oil refineries are causing ashortage. Since the char removed from the gasifier is also derived from biomass, undergroundcarbon fixation or use as a fertilizer can be considered. If such hydrocarbons can be synthesizedfrom carbon monoxide and hydrogen, they can be produced by replacing FT synthesis with therelevant processes.
As described so far, it can be said that biomass gasification is one of the energy transition
technologies capable of replacing the chemical industrial processes that have been conventionallycarried out using fossil fuels. Because of the recent implementation of the feed-in tariff (FIT)
system for renewable energy, many biomass power generation facilities have been built in Japan.
Since biomass is a solid like coal, it is used as an alternative to coal or a fuel for decarbonization in
power generation. If we aspire to zero emissions in the years to come, the replacement of petroleum
and its decarbonization will also be discussed. In this case, the possible alternatives are considered
to be biomass or hydrocarbons synthesized using atmospheric CO2 and renewable hydrogen. Itwould be possible to use CO2 and renewable hydrogen as feedstocks, if renewable electricity prices
decline and CO2 can be extracted from the atmosphere at low cost. However, in the meantime,
biomass will be the feedstock. The synthesis of chemical products by means of biomass
gasification will first be advanced technologically through the production of aviation fuel, which
has no alternative means, and will be implemented in society. Depending on how decarbonization
will progress, biomass may also serve as a major raw material in chemical production. When thishappens, biomass gasification is expected to play a critical role as the key energy transition
technology.

|5. Conclusion
Since around the end of the 1990s, we have developed the biomass gasification technology.
Having applied the technology to the production of bio-jet fuel (one type of SAF), we verified its
viability through a demonstration of the process involved. With this technology, syngas with stableproperties can be produced. This is therefore a gasification technology suitable for the processes ofchemical synthesis and is also a carbon energy conversion technology that will substitute petroleum
in the future and produce environmentally superior fuels and raw materials suitable for chemicalproduction.
While promoting the practical application of gasification technology for the production ofbio-jet fuel, we expect that it will also become a technology to supply raw materials for chemicalproduction.
Some of the results presented in this report is based on results obtained from a projectcommissioned by the New Energy and Industrial Technology Development Organization (NEDO)(JPNP17005).

Mitsubishi Heavy Industries Technical Review Vol. 59 No. 4 (December 2022)
8References
(1)
(2)

(3)

(4)
(5)
(6)
(7)

Atsushi Fujii et. al, ，Development of Bio Jet Fuel Production System，Mitsubishi Heavy IndustriesTechnical Review, Vol.58 No.3 (2021)
K. Okai etc. Emission and Engine Operation with SAF (Sustainable Aviation Fuel) Produced throughIntegrated Process of Woody Biomass Gasification and Fisher-Tropsch Synthesis, AIAA Propulsion andEnergy Forum, August 9-11, 2021
Flights were conducted by domestic airlines using domestic SAF, Press and Public Relations, Ministry ofLand, Infrastructure, Transport and Tourism Website, 18. Jul. 2021,
https://www.mlit.go.jp/report/press/kouku08_hh_000023.html
Aviation Fuel Expert Committee, Petroleum Association of Japan, MANUAL FOR PROPERHANDLING OF SUSTAINABLE AVIATION FUEL (SAF) ISSUE 1, Aug. 2021
CORSIA SUPPORTING DOCUMENT CORSIA Eligible Fuels-Life Cycle Assessment Methodology,
June 2019
ISCC Website, Sustainable Aviation Fuels Certification with ISCC,
https://www.iscc-system.org/about/sustainable-aviation-fuels/corsia/
RSB Website, CORSIA CERTIFICATION，https://rsb.org/rsb-corsia-certification/