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How to Convert Ethane to Ethylene

The predominant method of converting ethane to ethylene is the steam cracking process. This involves heating a hydrocarbon feedstock, in this case, ethane -- but it could also be naphtha or gas oil -- and breaking down the particles via steam to create ethylene. A relatively newer technology is a process known as oxidative dehydrogenation, in which ethane, oxygen and nitrogen are made to react with a platinum catalyst to produce ethylene without as much coking as in the first method. The U.S. Department of Energy is working to find better catalysts to make the latter more economically viable.

Instructions

- 1
  Steam crack ethane in tubular reactors called radiant tubes that take up one part of a furnace. Pass the ethane feedstock through an initial convection section of the furnace where it is preheated. Introduce steam at this stage, as well, which lowers the pressure and removes coke, or carbonaceous residue. Heat the mixture to the cracking temperature of 700 up to 900 degrees Celsius when it reaches the radiant section. Quench the emergent product at this point to stop any further reactions. Then, take the emergent product to be separated into ethylene, gasoline, methane, propane, among others products.
- 2
  Heat the mixture in a reactor so that the ethane undergoes oxidative dehydrogenation, a process which will combine ethane with oxygen and nitrogen, and possibly also hydrogen. Introduce the mixture inside the reactor to a monolith containing a platinum catalyst. Do this for only a short period of contact time, approximately 5 minutes. Produce ethylene from these reactions, along with carbon monoxide, water and hydrogen, and to a lesser extent, carbon dioxide, acetylene and methane.
- 3
  Add hydrogen to the mixture of ethane and oxygen in an oxidative dehydrogenation scheme in a ratio of 2:2:1 ethane to hydrogen to oxygen to improve the conversion rate of ethane, where hydrogen will be preferentially oxidated over ethane.

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