Japan Bolsters Fuel Ammonia Combustion at Gas Turbines, Coal Boilers

Japan is furnishing $500 million (59.8 billion yen) to much-watched projects that will develop and demonstrate 100% fuel ammonia combustion technology for gas turbines and 50% co-firing at coal boilers, as part of an effort to build out the nation's supply chain for fuel ammonia.

The country's national research agency New Energy and Industrial Technology Development Organization (NEDO) on Jan. 7 announced the funding under the Green Innovation Fund. One aspect of the 10-year Fuel Ammonia Supply Chain Construction Project" will seek to tamp down ammonia production costs to the high 10-yen [$0.09] range per Nm³ (hydrogen equivalent in terms of calorific value) by 2030. The grant will also develop burner technology to enable high co-firing and dedicated combustion for power generation, the agency said. In this way, we aim to solve the technical issues for expanding and popularizing the use of fuel ammonia and build a fuel ammonia supply chain," it said.

The initiative is rooted in Japan's October 2020-announced ambitions to become carbon neutral in 2050. While the country heavily depends on coal and liquefied natural gas fuel for power generation, it intends to boost electrification; ramp up its use of hydrogen, methanation, synthesis fuel, and biomass; and decarbonize its coal and gas fleets. Current targets require that 10% of Japan's electricity by 2050 and at least 1% (around 1 GW) by 2030 will come from hydrogen or ammonia.

But the new initiative holds global interest given soaring attention on ammonia's future role in the power sector as decarbonization gains momentum. Experts have noted countries with limited direct access to sources of low-carbon power could use ammonia as a vector for hydrogen imports, because ammonia has a high hydrogen content per unit volume, and it can be easily liquefied. Ammonia can also be cracked to yield pure hydrogen for use in gas turbines, but it can also be combusted, directly fed into or co-fired at existing coal plants or gas turbines. Finally, like hydrogen, it can also be used as a seasonal storage medium for the power sector, offering a potentially cheaper alternative to batteries.

NEDO's funding will allow JERA and IHI Corp. to kick off a more ambitious project to showcase a 50% ammonia co-firing rate at Unit 4 or 5 of JERA's 4.1-GW Hekinan Thermal Power Station in Aichi Prefecture by 2028.

JERA is a joint venture between Tokyo Electric Power Co. (TEPCO) and Chubu Electric that is looking to shift its massive coal-fired fleet to 100% ammonia by 2050. IHI Corp. is a giant engineering and heavy-industry manufacturer that is developing an entire value chain for hydrogen and ammonia, and has goals to achieve ammonia fuel demand of 3 million tons per year (MTPA) by 2030 (and 30 MTPA by 2050). Both companies are heavily invested in hydrogen and ammonia co-firing at power plants.

Under a separate May 2021 grant from NEDO, the two companies kicked off a related project to demonstrate a 20% ammonia co-firing rate at the 1-GW Hekinan 4 by March 2025. In October 2021, notably, the companies announced they had begun small-volume utilization" at test burners installed at the adjacent Unit 5 as part of their effort to develop a large-volume co-firing burner for Unit 4. Replacing 2 of the 48 burners at Unit 5 with test burners, during the roughly 6 months from [October 2021] to March 2022, JERA and IHI will examine the effects of different burner materials and combustion times to identify the required conditions for co-firing burners," they said. Unit 5 uses about 200 tons of ammonia that is supplied from denitration tanks at the plant, they noted.

But NEDO's new funding kicks off a larger eight-year project with more ambitious goals. For one, the companies are now looking to develop a burner capable of co-firing at least 50% by fiscal year (FY) 2024. Based on the results, the two companies will decide whether to install the burners at the Hekinan Thermal Power Station. If the burners are installed, plans call for co-firing with at least 50% ammonia at the actual power plant to begin by FY 2028." NEDO noted the project will involve a feasibility study before the verification test.

Denitration tanks at Hekinan Thermal Power Station. Courtesy: JERA, IHI Corp.

NEDO's funding also notably bolsters a parallel project spearheaded by JERA and Mitsubishi Heavy Industries (MHI) to develop and demonstrate dedicated ammonia burners for coal boilers that MHI has manufactured. The project will include development of a high-mixed" combustion in the special combustion burner," but it could also extend to a proof of feasibility study in an actual machine.

By 2024, JERA and MHI intend to develop a new burner capable of single-fuel ammonia combustion and draw up a master plan for equipment to demonstrate its use in actual boilers," they said in a joint statement last week. Based on the results, the two companies will decide whether to install the burners at JERA's coal-fired boilers made by MHI. For the actual plant demonstrations, JERA and MHI plan to verify co-firing with at least 50% ammonia at two units with different boiler types by FY 2028."

NEDO's newest award includes one project to develop and demonstrate new catalysts for ammonia production, and another to further research and development (R&D) of green ammonia synthesis.

Spearheaded by an array of power generators-Chiyoda Corp., TEPCO, and JERA-one of these projects will establish independent ammonia synthesis technologies, based on the development of innovative catalysts. The project's key goal is to enhance the use of ammonia through lower production costs and to reduce carbon dioxide emissions from power generation plants.

JERA said R&D will be phased. Under the first stage, researchers develop new ammonia synthesis catalysts through a competitive development strategy between three industry/academia teams. Under the second stage, the team will develop new ammonia synthesis process/facilities to compete with Haber-Bosch-based technologies by utilizing lower temperature and pressure synthesis catalysts developed in the first stage to reduce production costs." The Haber-Bosch process, which was first deployed at scale in 1913, involves reacting hydrogen with nitrogen from air, and it remains the main process to produce ammonia today.

NEDO's batch funding in January also bolsters an effort by IHI Corp. and partnering academic research institutes to develop a dedicated 100% liquid ammonia combustion system for 2-MW-class gas turbines. The project will seek to acquire operational know-how," verify safety measures, and establish early social implementation."

IHI Corp.'s partners include Tohuku University, which will perform the lab-scale test, and National Institute of Advanced Industrial Science and Technology, which will perform a bench-scale test with a small combustor. IHI Corp. intends to support the actual machine" scale test as well as the 2-MW-class gas turbine demonstration test.

The new NEDO-funded project to achieve 100% ammonia firing in a gas turbine is a notable expansion to significant achievements IHI Corp. has made in recent years. In March 2018, the company demonstrated technology for 20% ammonia co-firing on a 2-MW IM270 aero-derivative gas turbine, while suppressing nitrogen oxide (NO_x) emissions. Under an ensuing NEDO project, which spanned April 2019 through March 2021, IHS Corp. said it raised the liquid ammonia co-firing ratio on a 2-MW-class gas turbine to 70% on a calorific basis, and even attained 100% liquid ammonia-fueled firing with this technology on a limited basis."

IHI Corp. in March 2021 said it raised the liquid ammonia co-firing ratio on a 2-MW-class gas turbine (shown here) to 70% on a calorific basis, and even attained 100% liquid ammonia-fueled firing with this technology on a limited basis." Courtesy: IHI Corp.

One of the biggest challenges ammonia combustion presents is that it burns at a rate approximately one-fifth that of natural gas, generates about half as much heat, and has an adiabatic flame temperature that is about 150C lower, IHI Corp. explained. Because it burns slower than natural gas, combustion stabilization is especially challenging. Another stability impediment is the high latent heat of vaporization of liquid ammonia, which causes temperatures inside combustors to plunge," it said. Scaling up also requires enlarging evaporators, control valves, and other peripheral equipment to increase gaseous ammonia injections into turbines-which potentially raise facility costs.

The technology proposed in May 2019 by IHI Corp., Professor Hideaki Kobayashi of Tohoku University, Japan's National Institute of Advanced Industrial Science and Technology, essentially sprays" liquid ammonia directly into combustors. That approach eliminated the need for expenditure on ammonia vaporizing and related peripheral equipment and enhanced controllability," IHI Corp. said.

Riding on recent achievements, IHI Corp., notably, in June 2021 joined forces with American gas turbine giant GE to collaboratively develop a gas turbine business roadmap for ammonia fuel in Asia. The Ammonia Roadmap will support the use of ammonia as a carbon-free fuel to lower carbon emissions in both existing and new gas turbines," the entities said. According to the MOU [memorandum of understanding], both companies will conduct advanced research on the marketplace volume of ammonia as well as feasibility studies for ammonia as feedstock for gas turbine power plant installations in Japan and across Asia."

Japanese gas turbine manufacturer Mitsubishi Power is also developing an ammonia-fired gas turbine. After it unveiled its development of a 40-MW-class gas turbine that can directly combust 100% ammonia in March 2021, Mitsubishi Power in August 2021 announced small-scale combustion tests showed promise. These tests were used to compile basic data on ammonia and coal co-firing and ammonia-exclusive firing. The company has also identified optimal systems and conditions for combustion after understanding the characteristics of ammonia firing. These include the generation of NO_x, which is a concern for ammonia firing, and the potential for unreacted residual ammonia to be released outside the power generation system," it said.

Mitsubishi Power is now working to demonstrate the technology using a full-sized combustion system. It said it will also take steps to implement the technology at an existing facility, with the aim of gradually introducing the ammonia fuel to the industry."

-Sonal Patelis a POWER senior associate editor (@sonalcpatel,@POWERmagazine).

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