エネルギー資源学講座

International and Regional Environment

国際エネルギー資源学分野

International Energy Resources

Carbon dioxide reduction through more efficient
resource utilization

教授 金 放鳴准教授 グラウゼ ギド

助教 バール カエル

Professor

Associate Professor

Assistant Professor

Fangming Jinwealth, this progress was accompanied by a rising atmospheric CO2 level. Today it is common knowledge that the constantly increasing
emission of CO2 causes the anthropogenic greenhouse effect and climate change. For future prosperity, it is necessary to abandon fossil fuels
and replace gas, oil, and coal by renewable resources.
One important factor is the utilization of waste biomass for the production of energy and chemicals. Also the development of the artificial
photosynthetic conversion of CO2 is a promising alternative to conventional technologies. And at last, sustainable management of resources

Kyle Bahr

Further investigations show that the metal composition in electroniccontaminants. Moreover, the temperature required for the plastic

waste is applicable as a catalyst for this reaction with similar yields.

degradation would also destroy the catalyst. Therefore, it is necessary

Therefore, aluminium powder produced with high energy demand

to develop new catalysts with higher temperature stability and lesscan be replaced by waste materials, which are difficult to treat

sensitivity to chemical impacts.

otherwise.

requires the recycling of waste materials for a closed loop of carbon materials.

The most challenging issue of our time is the rise of theAs an alternative pathway to fermentation in bioreactors, suchatmospheric CO2 level. With human activities burning fossil fuels,chemicals can be obtained by hydrothermal conversion in water at

we affect the global carbon cycle (Fig.1) over a time span that istemperatures between 200 and 300 ºC. At very low reaction times ofmuch longer than our own life. The reduction of CO2 emissions

seconds up to a view minutes, more than 30% of the biomass isrequires the termination of the use of gas, oil, coal.

converted in the presence of inorganic catalysts.

1.Chemicals from waste biomass

2.Artificial photosynthetic conversion of CO2

Biomass can be used to fill the gap. It is not only a potential source

Another promising way is the artificial photosynthetic conversionof energy, but offers also many ways for production of chemicals,of CO2 into fuels and chemicals. That is, solar energy is used towhich are conventionally produced from fossil oil (Fig.2). We focus

produce organic molecules and hydrogen directly from CO2 without

on the conversion of biomass that is commonly considered as waste.

the help of biological organisms.

Materials, such as food waste, straw from wheat or maize, or rice

In our approach, CO2 or NaHCO3 (sodium hydrogen carbonate) canhusk, can be used to convert into valuable chemicals，such as

be converted to formic acid or other chemicals at a temperature offormic acid, acetic acid, lactic acid, which could be the foundation

about 300 ºC and in the presence of metal powder from iron,for a chemistry based on biological sources.

aluminium, zinc, or manganese. The reaction with hydrogen derived
from water yields more than 60-90% with a selectivity of near 100%.

3. Depolymerization of polyolefins at
moderate with aluminum-titanium catalysts

4. Stakeholder analysis and agent-basedmodeling of geothermal resource utilization
In order to limit our impact on the global climate it is necessary to

Polyolefins are the most produced plastic materials in the world.

meet our energy needs while reducing our usage of fossil fuels. One

Their applications range from packaging materials and films to low

very promising alternative is found in geothermal energy, which canperformance household articles. Most of these materials have a very

be extracted from the earth and used directly or transformed into

short lifetime, being disposed rapidly. Some waste polyolefins areuseable electricity.

mechanical recycled without reaching the former properties (down-In addition to the technical obstacles of finding and developing

cycling). However, most of the polyolefin waste is incinerated orviable geothermal resources, there are many social challenges thatused as fuel in coke ovens and blast furnaces, ending up as carbon

must be overcome at each stage of the utilization process. Japan has

dioxide in the atmosphere. For the sake of the development of aa long history of direct geothermal use, which has contributed very

recycling oriented society, it is desirable to convert waste polyolefins

strongly to Japan’s cultural identity. Because of this, many people

into valuable resources.

worry that further utilization may stretch the capacity of the resource

Aluminum-titanium catalysts are frequently used for thetoo far and cause damage long-standing traditional usage. In order topolymerization of olefins, known as Ziegler-Natta-catalysis (Fig.3).

balance the respect that is owed to historical practice with theThese catalysts work in principle in both directions, polymerization

resource development that is needed for a sustainable future, it isand depolymerization. Therefore, old used plastic could be degradednecessary to understand the perspective of all stakeholders and workto olefins, which could be used again for the production of plastic

to create options that are agreeable to all parties.

materials – a resource cycle is established. Catalysts used forAgent-based modeling is a computational methodology that uses

polymerization, however, are sensitive to water, oxygen, and othersimple rules for individual interaction in order to understandDepartment of Environmental Studies for Advanced Society

Our world faces the greatest challenge in the history of mankind. For about 200 years since industrialization established a constant rise in

Guido Grauze

先進社会環境学専攻

より効率的なリソース利用による二酸化炭素の削減

complex aggregate behaviors. It has already been used in other areasof resource development to help forecast potential outcomes ofapplied stakeholder and policy strategies. It is a powerful tool that
may also be used in understanding how geothermal resources are
currently being used and how usage could be expanded in ways thathave the consensus of stakeholders.

OutlookThis kind of CO2 conversion will become essential for our lifestylethat depends so urgent on energy and plastic materials, both provided
by fossil fuels. Only if we accomplish the step from a fossil fuelFig.1 Chemicals from waste biomass

26 Coexistence Activity Report 2015

Fig.2 Global carbon cycle.

Fig.3 Resource cycle.

based to a sustainable society, mankind might challenge the future.

Coexistence Activity Report 201527