Wednesday, January 19, 2011

TCDP Thermo Catalytic Depolymerization

Its been a long time since the last 2 posts, but after making a few changes to the basic idea of this site (which took us two and a half years) we are now back on course with explaining the basics about our microfuel technology and share with the interested public where we are going from here.

So this time I will give more background about thermo-catalytic depolymerization to prepare everyone for the next post, which will be about MWDP, microwave depolymerization, the technology invented in our group.

For those who went through my last posts it shouldn't be too difficult to follow this final chapter about the basics behind TCDP. For those who haven't I recommend to have a look back at the last post first.

I think the best way to explain TCDP is to go through the term word by word while analyzing their intended meaning. And finally I want to go a little bit into the possibilities and implications of a stable and reliable continuous process technology supporting TCDP to make it work on a large scale.


Depolymerization is the contrary to polymerization, which means the building of large organic or carbon based molecules, called polymers, out of smaller building blocks. Therefore depolymerization means the break down or cracking of polymers into smaller molecules. In our context, the polymers are for example large organic molecules like cellulose, man made plastics or vulcanized rubber. When they are cracked in the proper way, the result will be a liquid mixture of molecules that has similar properties like the most useful oil products from fossil oil. Two things are required to do that: energy and a catalyst...


Thermal means "through the application of heat", meaning the required energy is added to a process in the form of heat. This is actually complemented by pressure in some existing implementations, acting as an additional form of energy input for a transformation process. The total amount of energy input required for a certain chemo physical transformation then determines the energy efficiency of such a process. Energy efficiency is obviously a very important factor when it comes to assessing cost and environmental impact of a biomass to energy conversion.


Probably the very first successfully run TCDP process is documented in a patent application by the German chemical conglomerate IG Farben in the 1920ties. Metals like iron and copper where used as catalysts. At that time zeolites with their superior capabilities had not yet been discovered. Today they are the material of choice for this process.

A zeolite combines two important capabilities in one material: a molecular sieve in the form of a siliceous crystal structure and a metallic catalyst function (Aluminum oxide). The combination of both is essential for many of their uses. Oil refineries are using them for over 50 years to improve their product yields, but they are also used in many different production processes and form an important ingredient in modern washing agents.

For those who want to know more about zeolites, please go to Professor Geoffrey L. Price Zeolite Page and have a look at his description.

Now somebody might think: all you have to do is build a small reactor that allows you to mix your garden waste with zeolite, heat up the mixture to the right temperature and voila, the next day you have diesel for your car and biochar for next years vegetable.
Well, in principle this is correct, however, many have tried over the years to design a simple continuous reactor which can exactly do this. They have learned the hard way that there are some technical issues to overcome before you get there. We will get back to this in a future article about the technical hurdles in building such a reactor. 

Until then please visit us on Bionic World to have a look at our reactors.