Now for the closing chapter of this three-part series decoding the science behind Swestep’s Catalytic Pressureless Depolymerization process, or CPD. CPD, a process which can transform solid organic waste into sustainable diesel, can seem pretty complicated. If you’ve been following along, after today’s read you should understand what CPD is, how it works and why it is such an innovative technology.
P is for Pressureless
Unlike “catalytic” and “depolymerization”, “pressureless” is a pretty easy term to understand. You might guess that pressureless means without pressure and you’d be right. However, understanding why going pressureless is noteworthy requires an explanation. To begin you have to jump back in time, all the way to the late 2009, which by my research is about as early as the nearest relative to CPD shows up in the scientific literature.
It is important to understand that CPD was not the first process to successfully turn organic waste into something like diesel (e.g. kerosene). At least two other processes predate CPD which achieve this goal: fast pyrolysis hydrotreating, commonly referred to simply as pyrolysis, and integrated hydropyrolysis-hydroconversion, or IH2. Without going into any detail about how these process work, suffice it to say that they are both basically catalytic depolymerization processes that require extremely high pressure and temperature. If you remember anything from high school chemistry you might remember that pressure and temperature are intimately related- as one goes up, so does the other. The problem here is that in order to create such extreme pressure and temperature a lot of energy is required. Since diesel is essentially an energy product these processes seriously chip into the net gain by spending energy to make energy.
For all of you investors out there, yes, you absolutely have to spend money to make money and the same holds true for most of our human preferred energy sources. But what if you could make the same amount of money by spending far less. Especially since we are working to promote green technologies, we want the largest return on energy investment as possible. Therein lies the advantage of going pressureless. CPD achieves the same goal as pyrolysis and IH2 but with far greater efficiency. Far less energy put in for the same amount of energy out.
Putting it all together
If you’ve been able to follow up to this point, the following summary should make perfect sense to you. Many plastics and other solid organic waste contain hydrocarbon polymers. Depolymerization of these products, typically referred to as feedstock, with the help of a catalyst, yields high quality diesel. While there are other processes that produce sustainable diesel from the same feedstock, CPD uses far less energy because it is pressureless. This advantage, built into the backbone of Swestep’s business, has finally allowed for a scalable version of this process. Finally, a process that can turn yesterday’s waste into tomorrow’s fuel.
A Wee Disclaimer:
I feel like now is a good time to state that while I am a scientist, I am not a chemical engineer. I simply have the tools that allow me to decipher and relay dense scientific jargon to a non-scientific audience. What I have written is simply the result of my own investigations. The primary publication that I used to source for information regarding CPD can be found here, though it is stuck behind a paywall. Little else is published (in English anyway) aside from the two main patents that cover the CPD technology which can be found here and here.