September 2021: Char-vest Moon

A project log for The Metabolizer

A living recycling center that eats trash and sunshine and poops recycled plastic objects

Sam SmithSam Smith 10/26/2021 at 18:500 Comments

[UPDATE 10/21/2021 -After 2018 I started posting my updates on my Patreon page, and so I'm filling in the back-logs for this project retroactively so the whole story is in both places. You can also read all of these posts with their original photo formatting here]

September 30th, 2021

Since I first started this project, my goal has been to demonstrate a system that can use sunshine to turn organic wastes into biochar, using the gas generated in the process to generate electricity to power a waste shredder that shreds up waste plastic that is fed into the trash printer, turning sunshine and waste into biochar, energy, and 3D printed plastic objects - a complete metabolic system nourished by trash and sunshine.

Over the past 5 years, with your support, I've gotten all the pieces of that system working individually, and now it's time to put them all together. 

This month, that meant putting a lot of things BACK together. Last month, I had fully disassembled the biochar reactor in order to try out a new design I've been working on, one that I hoped would make it easier to build, more efficient, and easier to operate. The first test, however, did NOT go so well. My thinking went like this:

If I insulate a 5-gallon metal bucket, and I put the heating element inside that bucket, maybe I can nest another 5-gallon bucket full of biomass fuel inside it, and that would make it possible to load and unload batches of biomass like fuel cartridges, 5 gallons at a time. It would make the whole systems SO much easier to use, instead of having to scoop out the charcoal every time.

In order to distribute the heat, I filled the bottom of the bucket with Zeolite pellets, a type of dessicant make from alumino-silicate clay. My thought was that the zeolite would get hot and transfer the heat of the burner to the nearby metal.

Unfortunately, that's not what happened. What actually happened is that I accidentally made lava. It turns out the zeolite is INCREDIBLY INSULATING, which seems obvious in retrospect, and it built up so much heat that it melted the zeolite into glass, and melted the nearby aluminum foil, which shorted out the heating element.

BAM. Lava. The good news is that all that really happened was I burned out my heating element, and got more than a little discouraged. But I used my Patreon budget to buy a new heating element and try again. This time, no zeolite. 

And this time it worked! Better than before, more efficient, easier to load and unload, and easier to measure the inputs and outputs. I ran a test using raw, VERY wet douglas fir chips, to see how well the system dealt with that level of moisture.

It turned out to take a lot more energy than usual, 8.1kWh in total, and it only pyrolized half the batch. In the process, it generated around 1 cubic meter of syngas, which I used to power the generator for about an hour in total, generating 250 watt-hours of power, a new record! It's not much, but even with extremely wet material I was still able to get an energy in to energy out efficiency of nearly 3%, which is also a new record for me.

I've begun putting together the final 3D model for how all the parts go together, which will become the basis of the documentation for how to build one. I'm hoping to make the initial release of the reactor documentation by the end of the year.

Now that the reactor is working, one of the final pieces is to get the trash printer running on the power produced by the generator. So I spent the last part of this month rebuilding the trash printer, which has been out of commission and in storage since the beginning of the pandemic. 

The wiring was a mess, and the table I was using was too big. So I had to take it all apart, transfer it to a smaller table, replace the Z motors, and mess with it for hours, but I finally got it printing again.

The Trash Printer, it turns out, when printing, takes about 160 watts. With the 250 watt-hours I generated, I could print a cup, bowl, vase, or turbine, which all take 1-2 hours to print. Now that I can finally measure these numbers, I know for sure that putting all the parts together is indeed possible. Now I just need to figure out how to do it!

Thank you for your support! I absolutely could not do this with out the support you all provide, giving me a budget to experiment and try new things and learn how to do this crazy thing better and better. Thank you! See you next month!