About Chemistry, Environment, Waste Management and Green Life Inspirations

26 July 2011

New Way to Convert CO2 into Methanol

Scientists are continuously working on to find an alternative to fossil fuels. We are familiar with the side effects of fossil fuels and its impact on environment. Right now the fossil fuels seem to be necessary evil we can’t do without. Scientists want alternative fuels that have none of the ill effects of traditional fuels.

For a long time researchers are eying the carbon dioxide as an alternative fuel. Because carbon dioxide emanation is a hotly-debated global issue. This gas is held responsible for greenhouse effect that in turn is causing irreversible climate change. Human beings are responsible for carbon dioxide emissions. This gas is produced when we use fossil fuels. This is not the exact figure but carbon dioxide’s amount is increasing in earth’s atmosphere by more than 30% since the industrial revolution. According to estimates of The Intergovernmental Panel on Climate Change (IPCC) the world requires to reduce the global carbon dioxide by 60% in order to stabilize it at present-day levels.

Scientific researches are focusing on solutions that reduce global warming. Presently there is one popular term known as “green chemistry” which aims at minimizing or altogether eliminating the use of hazardous substances to prevent environmental pollution. Scientists at the Singapore-based Institute of Bioengineering and Nanotechnology (IBN) are striving to make the mass production of methanol more cost-effective. This will result in reducing the amount of carbon dioxide released in the earth’s atmosphere. Scientists at the Singapore-based Institute of Bioengineering and Nanotechnology (IBN) have achieved an unparalleled feat by transforming carbon dioxide into methanol. Methanol is a widely used form of industrial feedstock and clean-burning biofuel.

Their main achievement was using “organocatalysts” and making the whole process non-toxic to produce the more useful chemical compound. Professor Jackie Y. Ying who is IBN executive director of the Institute of Bioengineering and Nanotechnology shares his views, “We are innovating effective methods of generating clean energy using green chemistry and nanotechnology. In the face of environmental pollution, global warming and increasing demands on diminishing fossil fuel resources, we hope to provide a viable alternative energy option for industry, and effective sequestration and conversion of carbon dioxide.”

At the IBN, scientists successfully made carbon dioxide react with a stable organocatalyst called N-heterocyclic carbene (NHC). This reaction took place under mild conditions in dry air. Siti Nurhanna Riduan who is the senior lab officer at IBN explained about the experiment, “NHCs have shown tremendous potential for activating and fixing carbon dioxide. Our work can contribute towards transforming excess carbon dioxide in the environment into useful products, such as methanol.”

Further they used a combination of silica and hydrogen known as hydrosilane. Hydrosilane is added to the NHC-activated carbon dioxide, which is converted into methanol through hydrolysis. Dr Yugen Zhang who is the IBN team leader and principal research scientist elaborates about the intricacies of the chemical reaction, “Hydrosilane provides hydrogen, which bonds with carbon dioxide in a reduction reaction. This carbon dioxide reduction is efficiently catalyzed by NHCs even at room temperature. Methanol can be easily obtained from the product of the carbon dioxide reaction.”

A New Leading Process For CO2 to Methanol


Mitsui Chemical Inc. of Japan has decided to begin construction of a pilot plant for continued development of producing methanol from industrial CO2 effluent and photocatalyst produced hydrogen. Due to build starting in October of 2008 with completion next February the plant is expected to go into use in March of 2010, the plant’s annual yield would work out to be the U.S. equivalent of over 33,000 gallons.

The construction will be at the company’s Osaka facilities where some 150 to 160 tons of CO2 can be obtained. The new plant is based on the cooperative work of Mitsui and the Research Institute of Innovative Technology for the Earth in Kyoto Japan. Mitsui has a nearly ten-year investment in the effort during the 1990s from which it is bringing a single unit photoelectrocatalyst hydrogen production technology. This process uses a highly efficient thin film, anatase titania photocatalyst that has a photon to current quantum efficiency of 60%. The yield of 220,000 pounds of methanol would need approximately 22% hydrogen by weight, some 48,400 pounds. Where the solar array will be installed isn’t discussed.


Mitsui Methanol Process Illustration

The CO2 side is from the Mitsui complex’s own process waste stream. The company makes the case that the cause of the research and investment is in mediation of CO2 emissions. It is a fully credible claim, yet the rise in petrochemical prices has to have a role in making the pilot investment worthwhile. The CO2 process is also based in results form the Research Institute’s “Chemical CO2 Immobilization Project.” Here Mitsui participated and took the research further with proprietary ultra high activity catalysts. This base research was in zinc oxide and copper catalysts that are upgraded to yield 44% efficiency for methane and 24% for ethylene from 82% of the carbon dioxide feed. This published rate does not deactivate the catalysts when operating in a pulsed bias.

The dollar investment is published at US$13.7 million or only $62.28 per annual gallon of capital cost. Without an operating expense it isn’t known how viable this venture might be, but the graph above notes that the output will be directed to valued added processes to yield things like olefins and aromatics.

The vague area is in the costs to sequester the CO2 and the use of the excess oxygen. It seems sensible that the unused 18% CO2 from the process would loop back in. The oxygen has value in O2 form and it’s a sure thing it won’t be vented as ozone.

Pilot plants are the first level scale up from the lab bench stage to check the real world practice and costs before trying an industrial sized plant. It’s quite interesting to see a number like less than $63.00 of capital costs even before the running expenses are factored in. What part of the capital costs would be the instrumentation that would not go forward to industrial sized builds isn’t known nor the other special one off costs that come from a first build.

What is illustrated is that in Japan at least, the sense that CO2 can be recycled back into the petrochemical stream is a viable idea that merits engineering and construction investments. It’s also noteworthy that they understand the importance of providing a source of hydrogen to maximize the product yield. The 82% CO2 used number is just outstanding. This is a much better concept than the US effort to somehow sequester and bury CO2. A few months ago the U.S. dropped a coal plant sequestration effort as it was simply too expensive. It is much smarter to make use of the value in the waste CO2 than try to make another kind of “landfill” for CO2. CO2 actually has value, as any green plant can tell you, and when processed up to a value added product it can stop being a topic of such contention.