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"Thermal depolymerization, Appel says, has proved to be 85 percent energy efficient for complex feedstocks, such as turkey offal: "That means for every 100 Btus in the feedstock, we use only 15 Btus to run the process." He contends the efficiency is even better for relatively dry raw materials, such as plastics."

So long as the efficiency is < 100% (which it must be) you cannot get 'something for nothing'. That 15% simply means you are putting in 100 Btus and getting 85 back as fuel.

Some feedstock contains 100 BTUs worth of energy locked into organic molecules in the form of waste. It takes 15 BTUs worth of energy to process that 100 BTUs out of the feedstock into 100 BTUs worth of oil, gas, etc. In other words, waste + 15 BTUs = 100 BTUs of energy. The "something for nothing" is the energy locked in the waste. It is like using 15 BTUs of energy to pump 100 BTUs of oil out of the ground and refine it into 100 BTUs of oil, gas, etc. You aren't making energy. You are converting it into a usable form. If, of course, this works as advertised.

You wrote:
That 15% simply means you are putting in 100 Btus and getting 85 back as fuel.

From the article:
That means for every 100 Btus in the feedstock, we use only 15 Btus to run the process

The process uses 15 Btus to produce 100 Btus. Keep in mind that 15 Btus comes from discarded plastic, used tires, waste from a turkey processing plant, etc.

Considering waste that would end up in landfills is being turned into energy, the process is actually better than getting something from nothing, imo.

Yeah, but we are talking about most of the "energy" coming from fairly useless stuff. When you look at the entire process of drilling and refining oil in the traditional sense, I'm sure its efficiency, when viewed as an entire process, isn't too great.

So long as the efficiency is < 100% (which it must be) you cannot get 'something for nothing'. That 15% simply means you are putting in 100 Btus and getting 85 back as fuel.

The raw materials aren't "nothing". They are carbon-based products that could burn even without processing. The fact that they are waste products -- some very difficult to dispose of -- would make this process desirable even at lower efficiencies. Recall the controversies over incenerators. If this is cleaner than incenerators, it will be useful even if it only partly pays its way.

My one big question revolves around heavy metals. When you grind up computer monitors, what becomes of the lead in the CRTs?

A quick google search on thermal depolymerization will turn up dozens of articles, including some on the turkey waste plant under construction. The folks building the plant are not promising a profit. They are doing it for efficient management of waste, with the hope of eventually breaking even.

In my opinion, any new technology that manages to break even in its first commercial application can probably be improved to the point of being profitble.

It is not a question of getting something for nothing. As I read the article, it says 85% based on using 15 btu's to run the process for every 100 btu's (equivalent) in the feedstock. They say they are using gas formed in the process to provide the energy to drive the depolymerization. This gives 85 btu's of energy available in the product coming out the other end of the process.

The 100 btu's (equivalent) in the feedstock stream is not being input as energy. It is just what is there. 15 of those available btu's are being used as energy to drive the process.

Without the depolymerization conversion process, the 100 btu's (equivalent) in the feedstock is not efficiently or environmentally available, in most cases. And the feedstock will not fuel your truck or car or fuel your home heating system.

We get net negative efficiencies when we start using fossil fuels to generate electricity to charge batteries to power "electric" automobiles vs. using the fossil fuels directly to power the automobile through its internal combustion engine. Don't let the environazi's fool us by citing the "efficiency" of the "electric" auto relating only to the so called efficiency of the electric engine in the auto. They lie.