new concept of hydrogen production methods

Scientists generates hydrogen as energy source from ethanol and sunlight

A team of researchers from Universitat Politecnica De Catalunya  the university of Aber deen (Scotland ) and university of Auckland ( New Zea-land ) uses ethanol and sunlight to generate hydrogen as a energy source. The result of study have been published in natural chemistry.

Jordi Llorca  director institute of energy technology and researcher  at Universitat Politecnica De  Catalunya’  Nano engineering research centre, is one of authors of study, which represents a major step towards using hydrogen as an alternative to fossil fuels. In the frame work of research, a fully scalable photo catalyst  was created that makes the hydrogen production process simpler  and cheaper as it takes place at ambient temperature and pressure.

The solid photo catalyst is placed in a container with ethanol and exposed ultra violet by agitation, stimulating the most energetic part of the solar spectrum. The devise contained a titanium dioxide semiconductor that in contact with sunlight generates electrons captured by metallic  gold nano  particles, which reacts with alcohol molecules to produce hydrogen. According to Llorca, the semiconductor’s structure and the contact with nano particles are crucial features in the design of the photo catalyst.

The amount of hydrogen and energy developed depends on the amount of catalyst used and area exposed to solar radiation. Researchers have generated up to 5 liters of hydrogen  per  kilogram of catalyst in one minute. If 9 kg of catalyst were  put in a ethanol tank and exposed to sunlight and hydrogen generated were used to power fuel cell, 3 kw of electricity would be obtained, an amount similar to that which is used in a home.

Llorca plans to design reactors with real life applications such as providing electricity to home, which he sees as an important step towards introducing hydrogen as an energy vector and gradually gaining independence from fossil fuels. One of advantages of hydrogen compared to electricity it can be stored. An Economical process based or renewable resources until now, solar generated hydrogen technique have largely relied on water. However , despite water being cheap and abundant , these  techniques  have gamer-ed   poor results and  material required is expensive. As alternative researchers suggested  using ethanol , a renewable and economical resources that is easily obtained from agriculture and forest waste ( 100 grams of glucose generates approximately 50 grams of ethanol). The photo catalyst is also much cheaper and simpler to use than materials employed in techniques with water as it uses very small gold particles a ranging in size from 2 to 12 nanometer ( 1 meter =1 Million nano metres ). The nano particles capture the free electrons generated when titanium oxide- used as a support base- comes into contact with sunlight.

During process, which is based on solar energy, the team also discovered that the size gold particles has no influence on production of hydrogen, unlike what occurs during wide spread process in which the catalyst  powder must be heated  to reaction temperature( Usually over 500 degree Celsius ) and therefore incurs an energy cost. In addition the catalyst more durable because it works at ambient temperature and pressure.

New green technology for hydrogen production

Researcher Mohamed Halabi  of Eind hoven  university of technology demonstrates a proof of a concept for new and green technology to produce high purity hydrogen from natural gas. This allows hydrogen to be produced in an elegant technique at much lower temperatures,  and without releasing carbon-dioxide into atmosphere.

Hydrogen is a valuable feed stock for petro- chemical industry and it may play a big role in the energy supply of future, as a green, non polluting and efficient energy carrier. If it is burnt, only water is formed. However , the conventional technology for hydrogen production from natural gas (steam reforming) is a high energy intensive process, operated at high processes ( up to 25 bar) and high temperature ( 850 degree Celsius ) with multistage subsequent separation and purification units. Moreover huge amount of CO2  have to be handled in post -processing steps.
T U Eind hoven has now developed  a new  and improved technology called “ Sorption enhanced catalytic reforming methane “ using novel catalyst and hydro talcite  -based sorbent  as a new system of materials. Hydrogen is produced on the active catalyst- and co generated CO2 is effectively absorbed on sorbent, hence preventing any CO2 emissions to the atmosphere.

Halabi “ direct production of high purity hydrogen and fuel conversion greater than 99.5% is exponentially achieved at low temperature range ( 450-500 degree Celsius ) and at pressure of 4.5 bar  with low level carbon dioxides impurities” less than  100 ppm.  The enormous reduction of reactor size, material loading, catalyst , sorbent ratio, and energy requirements are beneficial key factors for success of concept over conventional technologies.

Small size hydrogen generation plants for residual or industrial application operated at a relatively low pressure, of less than 4.5 bar  seems  to be feasible.

Dr. Mohamed Halabi   received PhD on May 9 ,2011 at TV End hoven based on his dissertation “ sorption enhanced catalytic reforming methane for pure hydrogen production-experimental and modeling “. He  conducted his research at the laboratory of chemical reactor engineering under supervision of prof . Jaap Schouton.