Good Grief back at Ya!
I apologize for replying late, but I hit my limit. I can’t quite justify the cost. Anyway, we make ourselves wealthy, by keeping our needs few!
If I read the information correctly, JBI is using a pyrolysis process. If you think the energy it took to make the plastic has anything at all to do with what can be recovered out of it you just totally misunderstand everything.
This process is based on receiving a waste plastic feedstock material. I assume that it might come in many forms. Some might be relatively narrow in their size distributions, shapes and morphologies. In order to make their process as efficient as it can be, I would bet that the degree of undesireable debris associated with it is a factor as it must be cleaned and disposed of (a cost and energy consumer). Once cleaned, I’ll bet there is an optimum size distribution.
Grinding plastics is difficult, you can shred them somewhat, but it’s a bitch, you can also freeze them to make them brittle to allow for a more typical grinding process to function. Comminution mills can be designed to perform in either direction and require energy to operate.
Personally, when attempting to understand the energy balance, I like to work with what is called the ‘specific energy’ of each individual 'unit operation'. Only then can you start to break down and unlock the hidden energy efficiencies/inefficiencies of the entire process.
In this case it would be something like; if crayon chunks are in a size distribution my processor likes, only a few kilojoules of energy per gram of crayon chunks is needed. Or BTU per ton, horsepower per pound, specific energy is energy per unit mass. But if I am handling crap that needs cleaned from input streams to landfills, then maybe I need more equipment, that besides its capital and maintenance cost, requires a much higher HP/ton for that front end process alone.
The main stage as I understand is a pyrolyisis stage. I have worked on transport reactors and gasifier designs which could be considered similar. We typically go a little hotter, but I would bet with something like polymers you want to be around 900 to 1000 degrees F, I don’t really know. I was gasifying waste coal. But, I will bet the environment is hot and void of oxygen. Any moisture is probably a contaminant also. Regardless, moisture has a btu/lb also that has to be accounted for. Heating element and reactor heat transfer is also super important. You would not believe how much more HP/ton, or BTU/lb or whatever specific energy unit you want to use it takes to supply the theoretical amount needed, to maintain a constant temperature profile. It is not too efficient of a process. What that means is it sucks down a lot of btu’s/lb to do just that stage of the process.
Then the cooling process to separate and liquefy takes energy and has its own not so great efficiencies. If there is a syngas (synthetic gas, basically a term used in a lot of processes that off-gas, some as the principle product some as a byproduct), that is often needing to be dealt with and/or used somehow. Once the process is going, I could envision a combined cycle to use the syngas to supplement the raw utility sourced gas needed to run the burners to maintain the processor temperature. That could improve energy efficiencies if gas burners are even used for the heating elements. Electric is a possibility also I would guess. Some of the syngas might even be recycled back to the reactor to maintain the reactor atmosphere to low oxygen concentrations. Oxygen in the process will really screw you up.
How long can the unit be run without a buildup problem, char, or fouling of sorts? What happens on a unit trip, how difficult to evaluate the chambers and be ready for a restart? Just a few questions I might have. I am not sure the exact details of the process conditions and chambers JBI is using.
But then comes a lot of the peripheral processes associated with obtaining, receiving, storing, reclaiming, conveying, screening , preprocessing, processing , collecting, containing and transporting final product that takes capital equipment, maintenance (material loss from attrition/corrosion, lubricants, even extending to the operators that have to drive cars to work and the gasoline that took – I know its not much, but …), plus the big one, the direct ENERGY used in the major processes, that ALL ADDS UP!
Finally, someone sums it up in its entirety, not cheating by ignoring little or BIG things here and there, and guess what, it takes X BTU/ton of product in energy alone to make a ton of the stuff and you get less than X BTU/ton out of it as its fuel heating value! Very often I have seen good experienced engineers state for X for a given process but left out a lot of the peripherals that are indeed real and important. Sometimes I see them leave out the typical unit operation efficiency.
For example, I had a senior research scientist show me his process that required a heating of 1mm by 4mm cylindrically shaped catalyst pellets. He took the heat capacity of the pellets and said he needed to heat them from ambient near 80F to about 750F. The heat capacity is in units of btu per pound per degree F. The delta F was 750-80 = 670F. The heat capacity of the catalyst pellet was 0.25 btu/lb-F. Thus, he said all he needed was about 670F(0.25 btu/lb-F)=167.5 btu/lb of material processed. He wanted to process 10000 per hour. Thus, he concluded his POWER requirement was 10000 lb/hr (167.5 btu/lb) = 1,675,000 btu/hr. He got an entire company to spend about a 2 million dollars on evaluating his process based on a presetation that hinged on the economics working at that energy utilization. It was a super shock to them when I told them that for the particular thing they were trying to do, the most likely best and most efficient processor was a fluidized bed heat exchanger. That it actually got some of the best competitive energy efficiencies, but it was only about 30% efficient. Its not like a motor in a perfect setting that might get 90%. i.e. - he really needed about 5.6 million Btu/hr heat source! Even though the reason for doing it was noble, this shot it right out of the water. He was dumbfounded. He hired a team to prove me wrong.
They came back about a week later with the bad news.
That is just a fraction of what I am taking about.
So, I am just curious, not trying to be positive or negative.
I am just trying to properly evaluate your process. Does anyone have that number? Does anyone even care?
I think you should. Even if it is a net-negative energy process, there are likely still reasons for doing it. it just changes the economics and the uses.
It might mean it is not a good idea at all to help save the world’s energy supplies. If net-negative, it actually wastes the earths resources. That ultimate loss would then, eventually in the end, be radiated into space. In the grand scheme, you would not want to PAY for fuel LOSS.
Maybe it helps mitigate atmospheric CO2 somehow?
That might be something you would pay for. I would need to look closer there. Atmospheric CO2, its effects, contributors, pluses and minuses are extremely distorted, in many cases by no deliberate intent. You really have to look at the whole picture in a wide context to make the best most optimum decisions in that area. A very narrow small example is methane that escapes from landfills (or cow farts believe it or not). It is far better to burn that and make CO2 and dump it into the atmosphere, plus you get energy out of it, than to let it escape. Why? Because one kilogram mole of methane has about 20-40 times the greenhouse gas effect as one kilogram mole of CO2. There is debate where it lies in that range, but no debate it is worse.
Maybe it just gives use more years to a landfill. That’s worth a lot.
Maybe it gives you a little of each and more, well that’s good too.
I don’t know. But I am curious about the energy balance of the process.
I see so many people making so many misguided decisions based on a misunderstanding of the true energy balance of many things, from individual company product designs to international geopolitical decisions on energy.
In ALL my investments, I try to keep an open mind and see as clearly as I can with the least of shaded glasses, while also recognizing those non-ideal aspects that plague every venture and company’s history, present and path forward. Knowing also that risks abound regardless of how firm something seems to be.
Have a great day
Wishing all longs the best of luck; never shorts, here or THERE.
HS
