Thermal Depolymerization

The history of this technology is fairly extensive and can be reviewed through the link to wikipedia. In its simplest manifestation, it attempts to emulate the process by which oil is produced in the geological environment. This a laudable objective.

Changing worlds technology has taken the lead in this commercialization attempt. From the press coverage they have garnered and their disclosure, it is fair to say that they have told their story well. Their silence over the past year speaks loudly to to the actual difficulties that are always encountered in this product development process.

I have personally have held back from jumping on their bandwagon simply because I truly appreciate the type of learning curve that they are trying to climb. And the curve can be incredibly costly. The fact is that high pressure process chemistry has lagged over the past one hundred years because of this. You really have to be able to throw away a very expensive pressure chamber when it fails. Imagine throwing away a submarine. The pressure to stick with what is built becomes overwhelming and perpetuating.

After saying that, I happen to love high pressure process chemistry because of its huge potential. The idea that we can flow organic wastes into black box and produce oil, mineral and water is compelling. The problem is the small five or ten ton pressure chambers that must handle pressures of around 600 atmospheres and high temperatures of 600 degrees.

These are the same specifications that are needed for the Haber process for producing nitrates. It is very much a technology that you want someone else to perfect so that you can license it.

Then there is the problem of feedstock. The only practical feedstock is the municipal waste and sewage stream. It is already been gathered in central locations so there is absolutely no need to factor in collection to the economic model. Success will quickly draw any surplus agricultural waste into the system if the city facility is operational.

Huge volume numbers are bandied about but underestimate the water content, which will add an unwanted second level of beneficiation to the waste(sewage) stream.

This led me to a thought experiment in which a mine shaft was sunk to a depth in which a water filled shaft would achieve the necessary pressures. This would provide an inlet for the waste steam which would descend down through the water column to the working pressure zone. We still have to engineer the chambers and the heat production equipment and heat exchange systems. A lot of issues would need to be considered, but I think it has a chance now that we are mastering the materials issue in Iceland on the geothermal systems.

Assuming that the fuels produced can sustain the temperature needed, and that the surplus water can exit as live steam, we have a high volume continuous process with a minimal labor input. It would be a remarkable engineering feat.

The bottom of the chamber would have to be sloped to allow the slow migration of materials to a solids recovery device and the oils and other lights need to be trapped in chambers forming the roof of the reaction chamber. Fluid jets can be placed in the floor to keep material moving and perhaps as a way to move heat.

Microwave energy might be used to top up the necessary heat content. As I said, it would be remarkable engineering feat. But if it worked properly, we convert the urban waste problem into an asset that produces a large volume of fuel oil as a benefit in a way that will be inexpensive to operate. A little like a dam.

At the present, the more likely approach will be an above ground processing plant in which tipping costs are reallocated to subsidize the plant. This is a great solution and has soluble engineering issues. And we are paying anyway, so why not for a better solution that produces auto fuel?

No comments:

Post a Comment