Providing a possible new way for the production of hydrogen gas, a research group has found a series of chemical reactions that allow, first, decomposing water in a manner which is not toxic nor corrosive, relatively low temperatures.
Hydrogen gas is a highly coveted for its many uses. The industry uses it for many things, from removing sulfur from crude oil to manufacture vitamins. And its combustion does not emit carbon dioxide into the atmosphere, could be feasible for winding resulting in a possible “hydrogen economy”, an implementation of their energy use as wide as today is oil.
But since there are deposits of pure hydrogen or anything like that derives easily the gas, must be obtained by processing other substances.
One way to get hydrogen is to use heat to split water into pure hydrogen and oxygen. This method is attractive because it can harness the waste heat emitted by other processes. So far, we have tried in two ways: using two steps and using the high temperatures (above 1,000 degrees Celsius), or through multiple steps to slightly lower temperatures, below 1,000 degrees.
A process of the latter type is the sulfur-iodine cycle, which has been working for some time in many parts of the world but has its drawbacks. Although this cycle operates at a maximum temperature of 850 degrees Celsius, also produces various toxic and corrosive liquids intermediate that must be handled carefully. The equivalent methods in the group of high temperature (over a thousand degrees) usually have simpler reactions and intermediates solid, but there are very few processes that produce waste heat as high temperatures.
The team of chemical engineer Mark Davis, California Institute of Technology (Caltech) in Pasadena, it was proposed to combine the best of both worlds: using solid, as is done in cycles of high temperatures, so that they could avoid the problems of toxicity and corrosion associated with liquids, but also finds a way to reduce the temperature.
Davis, Bingjun Xu and Yashodhan Bhawe have developed a series of four reactions starting with manganese oxide and sodium carbonate, which is a totally closed system: Water that enters the system in the second step comes entirely converted into hydrogen and oxygen in another phase of the cycle. That’s important because it means that nothing is lost hydrogen and oxygen, and the cycle can come up over and over again, breaking the water in the two gases.
In initial tests, researchers have found the proper functioning of this method running a discrete number of cycle times, and the next goal will be to demonstrate that it still works well after repeating the cycle thousands of times in the prototype converter, which endorse the design is feasible for practical applications.
Another objective is to complete the cycle by making some of the reactions occur more rapidly.