I was searching the internet for articles and came across the term “renewable natural gas”. I said to myself, “oh great, all I need now is another renewable to wrap my mind around”. I never have gotten a firm grip on this term. Every time I look it up and think I got it, I find myself stumbling around at conferences trying to remember, “what does that mean again?”
The phrase gives me the feeling of a moving target. It is not a phrase like “autoignition” nor “steady-state” nor “discharge pressure”. Renewable to me means restore to its original state; but I do not see how a process can renew energy back to sunlight nor wind. What there is renewable?
In my college years, I did university research. Back then I was taught that liquefaction means changing a material from solid to liquid – like coal liquefaction, conversion of coal to gasoline. When I entered industry, they told me that gas liquefaction is turning natural gas to LNG. Last time I opened my chemical engineering thermodynamics book, I read that this is called “condensation”.
Another one is the term “wet gas”. In engineering we have wet air and dry air. Wet air means that it has water content, even if the system is all gaseous. Dry air means no water content at all. But now I am told, wet gas is natural gas with water, but also it has ethane and butane. What? Sometimes I feel like that guy in the book “1984”. I see 4 fingers, but I am forced to see 5.
Anyways, here is a video that describes renewable natural gas. I read somewhere that renewable natural gas is interchangeable with natural gas. I thought wheat bread and rye bread were interchangeable. What do they mean when they say that methane is interchangeable with methane? Enjoy the video.