Ushio Has Developed Technology That Can Decompose and Make Harmless Low-concentration Nitrous Oxide (N2O) and Methane (CH4) Gases

Ushio announces that the company has developed technology that can decompose nitrous oxide (“N2O”) and methane (“CH4”) gases, which are greenhouse gasses, even at low concentrations in one reactor using Ushio’s light technology.

N2O and CH4, which have the very high global warming potential* of 300 times and 25 times that of carbon dioxide (“CO2”), respectively, are released from sites such as sewage treatment, medical anesthetic, and waste treatment facilities. In particular, it is difficult to decompose N2O using a low-temperature catalyst and capture the released gas, and there are no effective measures at present. N2O and CH4 are currently decomposed by burning them at a high temperature or using a high-temperature catalyst, but those methods produce a large amount of CO2 emissions in the high-temperature treatment process, and the wastewater generated in the catalytic process using ammonia solution must be discharged.

To solve these challenges, Ushio has developed technology that can decompose and render harmless these two types of gases in one process even at low concentrations using the UV technology Ushio has been cultivating since its foundation. The technology is also useful for high-concentration gases.  

Specifically, we conducted a test to irradiate a gas mixture of air and N2O/CH4 with UV light (for about 100 seconds) using an excimer lamp that produces UV light with a wavelength of 172nm. As a result, we confirmed that a decomposition rate of about 70% for N2O and 100% for CH4 can be achieved regardless of whether low (50 ppm/100 ppm) or high (5% [50,000 ppm]) concentrations. 


Not only can this technology decompose low-concentration greenhouse gases (N2O/CH4) in one reactor, for which there are no effective measures, but its most remarkable feature is that it can decompose them at an ordinary temperature and pressure so there is no need for a high-temperature treatment and a catalyst or reductant. 

If this technology were to be used, for example, at a medium-sized sewage treatment plant with a sewage inflow of about 30,000m3 a day, we were able to verify from the results of this test that theoretically N2O and CH4 emissions can be reduced by 2 and 5 tons, respectively, and 725 tons of CO2 emissions can be reduced annually.
(Estimation Conditions: Decomposition rate N2O 70% / CH4 100%; concentration N2O 30 ppm / CH4 150 ppm; global warming potential N2O 300 / CH4 25)

Ushio will continue research and development to put this technology into practical use with the aim to start a verification test in 2025 and start a business in 2030.

To realize the FY2030 long-term vision of “become a “light” solutions company,” Ushio has pursued the goal to solve future social issues with its businesses focused on “light” and grow its economic value through expanding social values. To achieve this goal, we have been proceeding with the research and development in an effort to contribute to addressing global warming, a big challenge in the world, using the optical, light source, and biological technologies Ushio has been cultivating since its foundation. This development is a part of such activities.  

With regards to measures to address global warming as well, Ushio will contribute to realizing a world where a global carbon net zero and wellbeing of people are in harmony with each other through social implementation using the “light” technology. 

* The global warming potential is a number that represents the potential to warm the Earth that other greenhouse gases have compared with the baseline of CO2 emissions. N2O and CH4 emissions are less than CO2 emissions but their global warming potential is high so measures to curb their emissions are considered to be essential nowadays.

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