BY DR. JOSE PALU-AY DACUDAO
Thus, the Haber–Bosch process became the main industrial process for the production of ammonia. Ammonia NH3 in turn is the chemical precursor to today’s nitrogenous fertilizers. In brief, Nitrogen N2 from the air is reacted with Hydrogen H2 to form ammonia NH3.
N2 + 3H2 → 2NH3
One would think that all people nowadays would be all praises for the Haber–Bosch process. This isn’t so.
For one thing, it’s an artificial man-made process, and so people into organic farming aren’t particularly going around trumpeting praises for it.
One must bear in mind however that organic farming has lower yields than industrial agriculture, which is powered by nitrogenous fertilizers derived from the Haber–Bosch process. The concentration of Nitrogen fixed in such artificially made fertilizers can never be matched by fertilizers from ‘organic’ sources (say manure, which is the feces of cow, carabao, goats and other hooved domestic animals). Although organic farming has expanded since the early 1900s (now at 70 million hectares, much of it in Australia), going completely back to organic fertilizers is like going back to the 1500s when all agriculture essentially used organic fertilizers (such as the aforementioned manure). Humanity in the 1800s had it much better because at least they could mine niter from Chile and Peru in order to make nitrogenous fertilizers.
For another thing, some so-called environmentalists point out that the Hydrogen used in the Haber–Bosch process comes from the number one precursor of commercial Hydrogen, namely methane CH4, which comes from natural gas, the third most commonly used fossil fuel after oil and coal. Note that methane CH4 contains carbon. In brief, using methane to make ammonia in the Haber–Bosch process releases the Carbon in methane as carbon dioxide CO2, a gas that environmentalists love to lambast, as it is considered to be a greenhouse gas that causes global warming.
The following is a brief summary of how commercial Hydrogen is produced.
First, the steam reforming process:
CH4 (methane) + H2O (water) → CO (carbon monoxide) + 3 H2 (Hydrogen)
Second, the water–gas shift reaction:
CO (carbon monoxide) + H2O (water) → CO2 (carbon dioxide) + H2 (Hydrogen)
Any carbon monoxide emitted by these processes into the atmosphere eventually gets oxidized into carbon dioxide (if not first absorbed by plants).
Does the Haber–Bosch process emit more carbon dioxide into the atmosphere? It superficially looks that way by the simplistic chemical equations above.
On the other side of the debate, quite obviously, the nitrogenous fertilizers that the Haber–Bosch process creates results in increased plant growth. This plant growth is powered by photosynthesis.
6CO2 + 6H2O → C6H12O6 + 6O2
The end result is that more carbon dioxide is taken from the atmosphere and fixed by plants in today’s extensive industrial agriculture.
The Haber–Bosch process arguably may be the single most massive way by which humanity is taking out carbon dioxide from the atmosphere. And it also feeds most of today’s humanity. (For comments and suggestions please email to mabuhibisaya2017@gmail.com)/PN
