Factoring in ALL the costs, and determining if the number of BTUs in the ethanol is greater than the number of BTUs used (as Diesel fuel and/or natural gas) in the planting, cultivation, and harvest, the transportation to the ethanol distillery, the actual input of energy required to brew, distill and collect the now 95% ethanol, then transporting the product to the refineries for combining into the retail product gasoline.
Now compare, on a cost basis, the energy required to convert a fraction of the natural gas (ethylene) to ethanol
C2H4 (ethylene) + H2O (water vapor) (in presence of a catalyst) -—> C2H5OH (ethanol)
Fast, being done on an industrial scale already, and MUCH less expensive than using corn or other grains to produce ethanol.
If the idea is to simply have ethanol mandated for motor fuel component.
Read the article part that describes the co . . Try not to omit the rest. It ain’t just ethanol that is at issue.
Enthlene production is a very energy intense process, unlike ETOh. I was a chemist for a few years long ago. The areas of an ethylene plant are:
steam cracking furnaces:
primary and secondary heat recovery with quench;
a dilution steam recycle system between the furnaces and the quench system;
primary compression of the cracked gas (3 stages of compression);
hydrogen sulfide and carbon dioxide removal (acid gas removal);
secondary compression (1 or 2 stages);
drying of the cracked gas;
cryogenic treatment;
all of the cold cracked gas stream goes to the demethanizer tower. The overhead stream from the demethanizer tower consists of all the hydrogen and methane that was in the cracked gas stream. Cryogenically (−250 °F (−157 °C)) treating this overhead stream separates hydrogen from methane. Methane recovery is critical to the economical operation of an ethylene plant.
the bottom stream from the demethanizer tower goes to the deethanizer tower. The overhead stream from the deethanizer tower consists of all the C
2’s that were in the cracked gas stream. The C
2 stream contains acetylene, which is explosive above 200 kPa (29 psi).[18] If the partial pressure of acetylene is expected to exceed these values, the C
2 stream is partially hydrogenated. The C
2’s then proceed to a C
2 splitter. The product ethylene is taken from the overhead of the tower and the ethane coming from the bottom of the splitter is recycled to the furnaces to be cracked again;
the bottom stream from the de-ethanizer tower goes to the depropanizer tower. The overhead stream from the depropanizer tower consists of all the C
3’s that were in the cracked gas stream. Before feeding the C
3’s to the C
3 splitter, the stream is hydrogenated to convert the methylacetylene and propadiene (allene) mix. This stream is then sent to the C
3 splitter. The overhead stream from the C
3 splitter is product propylene and the bottom stream is propane which is sent back to the furnaces for cracking or used as fuel.
The bottom stream from the depropanizer tower is fed to the debutanizer tower. The overhead stream from the debutanizer is all of the C
4’s that were in the cracked gas stream. The bottom stream from the debutanizer (light pyrolysis gasoline) consists of everything in the cracked gas stream that is C
5 or heavier.[11]