We’re all familiar with solar cells, be they photovoltaic, or for heating water. But they are only the more common ways of converting the sun’s energey into usable power, and to the extended list there is now an addition courtesy of [Dennis]. He’s using the sun to drive the pyrolysis of biomass waste, releasing hydrogen fuel.
For those who aren’t familiar with the chemistry, pyrolysis refers to chemical reactions triggered by heat. In this case, when organic biomass is heated in the absence of oxygen it breaks down and releases the gaseous products of that breakdown as well as a mass of carbon. The idea behind this pyrolysis cell is that a Fresnel lens will focus the sun on a reaction chamber, providing the required heat for the reaction to occur. A test with a magnifier and a test tube proves that there’s something in it.
Of course, sharp-eyed readers will notice that this isn’t quite in the same vein as other cells which convert the Sun’s energy into a usable form, in that while it provides an input of energy for the pyrolysis the chemical energy in the resulting gas comes mostly from the original biomass. There is a silver lining to the prospect of burning gas though, in that the left-over carbon can be incorporated into the soil as biochar, an effective carbon sink.
We’ve seen a project pursuing a similar chemistry before, though not using solar energy to do it.
When a rainforest is clearcut for agricultural use, we only see the surface problems: fewer trees, destruction of plant and animal habitats, and countless other negative effects on the environment. A lurking problem, however, is that the soil is often non-ideal for farming. When the soil is exhausted, the farmers move further into the rainforest and repeat the process.
In the Amazon, however, there are pockets of man-made soil that are incredibly nutrient-dense. Figuring out how to make this soil, known as Terra Preta, on a massive scale would limit the amount of forest destruction by providing farmers a soil with more longevity which will, in turn, limit the encroachment on the rainforest. That’s the goal of this Hackaday Prize entry by [Leonardo Zuniga]: a pyrolysis chemical reactor that can make this soil by turning organic matter into a type of charcoal that can be incorporated into the soil to make Terra Preta.
As a bonus to making this nutrient-dense soil on a massive scale, this reactor also generates usable energy as a byproduct of processing organic waste, which goes several steps beyond simple soil enrichment. If successful and scalable, this project could result in more efficient farming techniques, greater yields, and, best of all, less damage to the environment and less impact on the rainforests.
Can you build a foundry out of a loaf of bread and a can of tuna fish? As it turns out, yes you can. And not only can you melt aluminum in said foundry but you can also make a mold from plain beach sand and cast a usable part.
Through the magic of backwoods engineering and that can-do Canadian attitude, [AvE] demonstrates in his inimitable style how a pyrolized loaf of sourdough bread can serve as a perfectly acceptable foundry, using a tuna can as a crucible. We covered [AvE]’s carbon foam creation process before and showed some of its amazing properties, including the refractory characteristics requisite for foundry service. Once reduced to carbon foam, the bread can easily handle the flame of a propane torch and contain the heat long enough to melt aluminum. And using nothing more than beach sand, [AvE] was able to lost-foam cast a knob-like part. Pretty impressive results for such a low-end, field expedient setup.
Normally we warn our more tender-eared readers about [AvE]’s colorful language, lest they succumb to the vapors when he lets the salt out. But he showed remarkable restraint with this one, even with his cutting mat aflame. Pretty SFW, so enjoy seeing what you can do with nothing.
Continue reading “The Tuna Fish Sandwich Foundry”
Trillions of cigarettes are smoked every year, leaving behind discarded filters containing non-biodegradable materials that can be recycled into carbon-based products for electrochemical components. This was discovered by a team of South Korean scientists who presented their unique energy storage solution in IOP Publishing’s journal of Nanotechnology.
The materials inside the cigarette filters offered up better performance than commercially bought carbon, graphene and carbon nanotubes at the time. They hoped to coat electrodes of supercapacitors with the material to be inserted into computers, handheld devices, and electric vehicles. A simple one-step burning process called pyrolysis reduced the filters down into a carbon-based byproduct with tiny pores. The leftover porous substance ensured higher power densities for supercapacitors. This was then tested out to see how well the material absorbed electrolyte ions and discharged them. It did better than expected and stored higher amounts of electrical energy than other commercially available options.
The full paper is linked at the bottom of their article but it’s behind a paywall. If you have a subscription and the time to look it over, please let us know if you think there’s potential for this unorthodox material source or if they’re just blowing smoke.
[Thanks for the tip Ryoku!]