from Hacker News

Dutch designer drives his car on the plastic waste he collects

by akeck on 1/14/24, 7:40 PM with 88 comments

by jp57 on 1/14/24, 8:17 PM
The plastic waste is heated in a boiler to about 700 degrees Celsius, after which it evaporates. The gas is then cooled down and turns into a diesel-like liquid one hour later.
A kind of pyrolysis, I assume, and very energy intensive. Does this process really produce more stored energy in the output product than it took to run the reaction?
by yread on 1/14/24, 9:26 PM
There is a video (in Dutch) https://www.autovisie.nl/video/uw-garage/gijs-rijdt-met-zijn...
You can see how dirty the burning is producing soot-heavy smoke when he drives it around Arnhem
by Neil44 on 1/14/24, 9:23 PM
How do you get 2.7kg of carbon by burning 1kg of plastic? Am I thinking too simplistically about that? Also he's currently using industrial plastic chips, high quality homogeneous material, if you were using plastic garbage you then run into contaminants, full bottles of whatever, labels, glues different types of plastic - not all plastics will liqify etc etc etc. Well done for the proof of concept though.
by tsimionescu on 1/14/24, 8:23 PM
So he's trying to increase his greenhouse gas emissions as much as possible?
Plastic waste is carbon that isn't going into the atmosphere, not very fast at least. Turning it back into oil and then burning that is the very opposite of what we should be doing with it.
by SigmundA on 1/14/24, 10:16 PM
In my area they burn garbage for electricity[1] which a lot of the content will be plastics, they collect metals from the ash. As mentioned it still releases carbon in to the atmosphere but better than this setup since the emissions controls are much better as they are with most power plants.
With an electric car you are not limited to any one fuel, whether it be solar, wind, hydro, nuclear, nat gas, oil, coal or plastic / garbage this is the big win decoupling fuel from transport.
1. https://pinellas.gov/waste-to-energy-facility/
by WalterBright on 1/14/24, 10:19 PM
> Because of the chemicals added to plastic, burning it to make fuel creates a lot of nasty air pollution.
Even a tiny whiff of burning plastic makes me nauseous for hours. I want nothing to do with that. If I seal clothes in a plastic tub for a few years, the clothes take on a plastic smell that also makes me nauseous. It doesn't wash out, so those clothes get thrown out. Long ago I got rid of all the dishes made of plastic. Even plastic cups impart a plasticy taste to water.
by Uptrenda on 1/15/24, 1:25 AM
I've seen YT videos of people building these stills to break down the plastic to 'diesel.' Normally they claim that they're 'recycling' the plastic and imply its an ingenious way to help better the environment. But there's a few things worth noting here:
1. The still needs a way to generate heat to work. A primitive method done in some poorer countries (and in DIY stills) is to use wood to heat it. Guessing the way his still works here relies on fossil fuels to incinerate the plastic (maybe butane or his own fuel -- but if using his own fuel then he would have needed to bootstrap it.)
2. I realize the article mentions this but unless you read the entire article carefully you may not notice this. A lot of people are just going to assume that the designer found a way to recycle plastic without realizing how insanely toxic what they're doing is. Even in the incinerators designed for this purpose scientists have found chemicals in their ashes that never break down from combustion.
3. The author of this article makes frankly a bizarre logical leap by saying that since plastics are already burnt in incinerators doing this isn't that different. They neglect to mention that incinerators are still horrible ways to dispose of waste and that plastic specifically can be recycled into other materials without burning it into a toxic mess.
Overall, the still will generate an extremely dirty fuel capable of being used by ancient engines. For the modern gentleman who gives absolutely zero fucks about the environment. A possible next step from this project would be to figure out how to run a car on nuclear waste so that your car can be a fukushima/chernobyl on wheels.
by dotancohen on 1/14/24, 8:24 PM
The article suggests that the fuel is made completely on site (on the roof of the vehicle) from discarded plastic chips from a neighbor's business. But some numbers do not add up.
```
  > Making 1 liter of diesel requires burning 1 kg of plastic, which results in 2-2.7 kg of carbon emissions.
```
Does that number (1 kg) include the plastic consumed in the burning process, whose heat is then used to define (opposite of refine) the plastic back to liquid? How does 1 kg of plastic contain 2 kg of carbon? Or is the O2 in CO2 so heavy that "carbon emissions" weigh significantly more than the source hydrocarbon?
```
  > Second, there is the combustion of diesel fuel while driving, which emits 2.7 kg of carbon dioxide per liter.
```
Same question.
by bdcravens on 1/14/24, 8:27 PM
So he's basically just making diesel fuel, which could be done as a separate process, and used in any diesel-compatible engine (I presume)
> 1 kg of plastic gives 0.5 liters of diesel, so the fuel economy is 7.14 liters per 100 km
This converts to about 33 MPG
https://convertermaniacs.com/liter-per-100-kilometers-to-mil...
by MuffinFlavored on 1/14/24, 9:21 PM
Are there metrics on how many `kg` of plastic waste required input wise -> how many `l` of "diesel like liquid" output? how many "kilometers per liter" is the car getting on the diesel / how many "kilometers per kg of plastic"? Curious on yield/waste/efficiency/etc.
by eterevsky on 1/14/24, 9:04 PM
It's _much_ better to burning trash in special facilities, where it is burnt down to CO2, rather to some kind of soot that will pollute the atmosphere. It will also be more efficient in terms of energy production.
by yreg on 1/14/24, 8:08 PM
Fuel consumption: 14 kg of plastic per 100 km, but to be fair it's a Volvo 240 with a tiny refinery mounted on the roof.
Why don't the fuel producers do this? Is it less efficient than recycling the waste?
by stere0 on 1/14/24, 8:39 PM
I'm not a chemist, but isn't this an application of the Fischer Tropsch process similar to coal to liquid and gas to liquid?
by foul on 1/14/24, 10:45 PM
Woodgas vehicles were enormously inefficient. Said that, rest of the story is sick AF, he made a pyrolithic device all by himself.
by M95D on 1/15/24, 8:51 AM
I'm interested to know if non-recyclable plastic (everything not PET) can be used.
by jokoon on 1/14/24, 10:35 PM
It's ridiculous what people will do to keep using their car