About Chemistry, Environment, Waste Management and Green Life Inspirations

05 October 2010

SOLAR HYDROGEN POWER FOR HOMES

 by Bruce Mulliken, Green Energy News
Utility companies need not lose any sleep: It will be a long time before significant numbers of homeowners in the industrial world will be able to disconnect from the grid. While the cost of generating power from intermittent renewables, such as solar and small wind, may be dropping (with generous government incentives to help), the cost of storing power is still prohibitively high. If intermittent renewable energy can’t be stored then the power cable between home and grid can’t be disconnected.
(Lucky the developing world, though. Where there is no power grid, the norm of the future may be to install independent home generating stations rather than build a formal power grid infrastructure. If so, the developing world will have the green state-of-the-art power system while the industrial world will keep its outdated, inefficient, dirty, centralized power distribution system.)
Batteries, for the time being, are currently in the forefront of energy storage for homes. But, Sun Catalytix of Cambridge, Massachusetts thinks a better solution would be to use electricity from solar photovoltaic panels to split water into hydrogen and oxygen and store both gases in tanks to be fed into a fuel cell to generate power (and perhaps heat) when the Sun drops below the horizon. Solar energy plus energy storage in the form of hydrogen and oxygen would equal an off-grid, personalized energy system.
Daniel Nocera, Ph.D. in discussing his work on solar hydrogen systems at Sun Catalytix, and his day job at the Massachusetts Institute of Technology, said at the 240th National Meeting of the American Chemical Society, "Our goal is to make each home its own power station. We're working toward development of 'personalized' energy units that can be manufactured, distributed and installed inexpensively. There certainly are major obstacles to be overcome — existing fuel cells and solar cells must be improved, for instance. Nevertheless, one can envision villages in India and Africa not long from now purchasing an affordable basic system."
solarfuelcell526
A new catalyst could help speed development of inexpensive home-brewed solar energy systems for powering homes and plug-in cars during the day (left) and for producing electricity from a fuel cell at night (right).
Credit: Patrick Gillooly/MIT
With stored pure oxygen in tanks being used to feed the fuel cell, the power plant is bound to be more efficient than a typical hydrogen fuel cell which would use oxygen from the surrounding air to combine with hydrogen to generate electricity. Air, after all, is only about 21 percent oxygen. With 100 percent oxygen a fuel cell should work very well. Nocera’s work is to improve the oxygen generation capabilities of electrolyzers which split water. His low-cost catalysts wouldn’t require expensive platinum and would be able to boost oxygen production by 200 times. That’s a lot of oxygen.
Still, as much as solar-hydrogen-oxygen power systems seem appealing they would have to be made safe. Storing oxygen is dangerous business. Pure oxygen in itself doesn’t burn, and is not considered a flammable gas. Oxygen, however, does support – with great gusto – the burning of other substances. It’s the oxygen component in air that makes things combust or oxidize. Oxygen stored in tanks must always be treated with caution. Pure oxygen and hydrogen are fuels of rocket engines, by the way.
If the Nocera/Sun Catalytix catalyst works well and gas storage can be made safe, then this energy storage could be a competitor to batteries, provided hydrogen fuel cells, too, come down in cost. Using pure oxygen instead of air should allow the fuel cell stack – the core of a fuel cell – to be smaller thus decrease its cost.
Links
American Chemical Society
http://www.acs.org

PLASTOLEUM ( Plastic to oil)

MUTHUKUMARAN VENKATACHALAPATHY
VILLUPURAM, TAMIL NADU INDIA

Sustainable Technologies
Jun 7, 2010


Petroleum and plastic cannot be explained discretely, as plastic is nothing but one of the many useful products derived by processing petroleum. Plastic is obtained when crude petroleum is processed and treated with a few other additives. This would basically make plastic a polymer of hydrocarbon with few other elements.

If plastic can be made from hydrocarbons they can also be reverted back into oil. This has already been proven by experiments and trials have also come out fruitful.We intend to propose a processing unit to use this waste and get some fuel. The pros in this are two fold. First being reducing environmental pollution to a great extent and second, to get more of the black gold, both of which are the dire needs of the hour.

Degradation of polymer in plastic occurs when the long chain of monomers breaks at certain points. Plastic waste can be converted into liquid hydrocarbons by random de-polymerisation. The process is carried out in a specially designed reactor in the absence of oxygen and with Zadgaonkar’s catalytic additive and Solar furnaces.
Maximum reaction temperature is 350deg C and there is total conversion of waste plastic into value-added fuel products.

The intended technology shall use a process called catalytic pyrolysis and infrared source with different range of frequencies (backup), which can act on hydrocarbon materials to efficiently convert plastics to crude oil. Forced air, heated by solar furnaces/burner, shall be used to indirectly heat the feedstock inside the process vessel. The energy transferred to the plastic feedstock from the burner shall be used to depolymerise, or crack, the plastic into synthetic crude oil.

Oil shall be chromatographically removed from the waste plastic and aggregated from several vessels for on-site micro-refinement.A single module is expected to produce up to >750 litres of crude oil for every ton of typical plastic waste processed. System capacity can range from 200 tons to 400 tons of plastic wastes processed per month.

The natural gas and sludge left over after oil extraction from plastic waste shall be used to run the (backup) far infrared ray heating system that breaks down the plastic fed into the generator. This technology is extremely safe. And because the system does not incinerate the plastic, there is little cleanup involved and there are virtually no emissions.The technology shall be capable of breaking down any plastic waste into oil, though some plastics may produce more oil than others.

A reactor shall convert waste plastic feedstock into oil through low temperature thermal cracking (Using Solar furnaces) in a vacuum, extracting the hydrocarbons embedded in petroleum-based plastic waste with the use of a catalyst. Some of the by-products of the conversion process may be made use to power the unit. Vent gas may be recycled to provide electricity and excess oil residue is transformed into emulsified heavy oil.This is carbon negative as an oil producer and the CO2 released by the reactor shall be minimal.All types of plastics can be transformed into oil using this technology.