How to turn plastic waste into diesel fuel cheaply

[sixth sense]

Thanks for posting this up, dont follow the equasions but i gather you are saying that a cold enough fluid moving at a brisk rate can control the temp far in excess of 100'c, i am leaning back towards using a berr cooler i have idle here, it has a double inlet & outlet meaning the water can pass through the cooling coils twice before it goes back into the condensors & the temp of the water that cools the condensor water as it passes through submerged coils can be thermostatically controlled to almost freezing.

What flow rate would you imagine the water would need to be circultaing and entering the condensor at say 2'c to be able to cool the vapour at 200.c?

Sorry for the questions, unfortunatley i never excelled in my education having left school with poor results & not progressing on to third level, saying that, mind you i have a keen mind & ability to understand dynamics & tolerances if i am guided through a little.

Also for the record, i work as a health & safety officer so i am fully trained in risk assessing equipment for anny potential hazards, any work i will have undertaken will be with prior consultation with professionals & any work i cannot undertake will be done by competent enginneers.

What would you guys reckon to an old beer keg as a reactor? To thin?

The beer cooler is not a good condenser for this application. there is a minimal surface area between the cooling liquid and the substance to be child. A good condenser should have a lot of surface area in contact with the cooling medium , just like a car radiator or your window type aircon's aircooled condenser.

[imakebiodiesel]

I do not find wvo distillation offensive, I simply have no interest in it , my interest is in pyrolysing plastic to oil.
When you suggest the work of Jetjis is bogus , or that only people with degrees in chemistry should experiment with fuels, or that your statements should be posted permanently at the header of this topic, I am not offended, just a bit astonished.

Uncorruptable, my apologies, you are right Zetor tractors are in fact made in what is now the Czech Republic.

[thissideup]

Is there any reason both WMO and Plastic cant be processed together? all along it was my intent to start my reactor with plastic then pump in wmo after the plastic has been processed, so I can get throught a full day without opening it and refilling. But after reading the latest posts, Im concerned I may be missing something.

[thissideup]

Is there any reason both WMO and Plastic cant be processed together? all along it was my intent to start my reactor with plastic then pump in wmo after the plastic has been processed, so I can get throught a full day without opening it and refilling. But after reading the latest posts, Im concerned I may be missing something.

[Excalibur]

Is there any reason both WMO and Plastic cant be processed together? .

My last batch was a blend of plastic and clean wmo. In that case the fuel came out very clear. One benefit of a blend would be that the oil and plastic combine to a slurry. This can be continuously fed to the reactor without air pockets as wouldn't be the case with plastic alone.

[Uncorruptable]

I have already discussed this. If you are not purging your retort and distillation column, regardless of whether you are cracking plastics or distilling WMO, then you are likely to have a serious fire. Oxygen should be removed from your entire process at all times.

Anyone who discusses cracking plastics or distilling WMO, and does not emphasize the importance of removal of oxygen from your process is wholly irresponsible.

I hear you, from waht i have gathered reading over the forum pages & replies, is that the displacment of oxgen in a small batch converter (50 litres) occurs fairly qucikly before you reach a crtical point in boiling if it is WMO you are working on.

To be honest, it is this part of the entire process that has me worried.

The beer cooler is not a good condenser for this application. there is a minimal surface area between the cooling liquid and the substance to be child. A good condenser should have a lot of surface area in contact with the cooling medium , just like a car radiator or your window type aircon's aircooled condenser.

Sorry sixth sense, you picked up my post wrong, i was asking if it is suited as a reactor chamber & was advised most likeley for WMO only & not plastics.

Uncorruptable, my apologies, you are right Zetor tractors are in fact made in what is now the Czech Republic.

No worries at all, just that my uncle actually used to work for them.

[Beyond Biodiesel]

I do not find wvo distillation offensive, I simply have no interest in it , my interest is in pyrolysing plastic to oil.
When you suggest the work of Jetjis is bogus , or that only people with degrees in chemistry should experiment with fuels, or that your statements should be posted permanently at the header of this topic, I am not offended, just a bit astonished.

The pyrolysis of rubber and plastics, and cracking and distillation of WMO are all extremely hazardous practices that must carry with them a great deal of caution. Anyone who proposes these practices without a thoroughly worked out process and safety message is wholly irresponsible.

Is there any reason both WMO and Plastic cant be processed together? all along it was my intent to start my reactor with plastic then pump in wmo after the plastic has been processed, so I can get throught a full day without opening it and refilling. But after reading the latest posts, Im concerned I may be missing something.

There is no reason why anyone could not process WMO and plastics back-to-back, or in the same batch. They are all just hydrocarbons.

I hear you, from waht i have gathered reading over the forum pages & replies, is that the displacment of oxgen in a small batch converter (50 litres) occurs fairly qucikly before you reach a crtical point in boiling if it is WMO you are working on.

To be honest, it is this part of the entire process that has me worried.

Well, the method of displacing oxygen by filling the retort/reactor with water prior to turning on the heat has some merit, because the water turned into steam will displace oxygen. However, what do you do when all of the water is gone, and your retort/reactor develops a leak?

If you maintain a positive pressure in your retort/reactor with a purge gas, then the potential fire hazard is reduced, but not eliminated.

If your retort/reactor goes up in flames what do you do? If you have a large container of CO2 nearby you can shower the retort/reactor distillation column with CO2.

If you do not maintain a positive pressure in your retort/reactor with a purge gas, then you turn off the heat, what happens? As the retort/reactor cools it will develop a negative pressure which will draw O2 from the exit of your system. When that O2 gets anywhere near a hot hydrocarbon in its vapor stage inside your system you have a potential explosion hazard because hydrocarbons in vapor form combined with O2 at 4:1 ratio equals ignition.

[CRMoore]

Should 50 kg/litre be the lower limit what size? I see this like composting- a domestic way of dealing with refuse. I would like to see it available, safe, efficient and affordable. But when will this be ?

[imakebiodiesel]

Taking the potential risks involved in hydrocarbon cracking Im not sure this could ever be an activity carried out in a typical suburban house.
Im a organic gardener myself and an enthusiast for home composting but there is very little risk of my composter exploding and burning my house down.
I see it more as a unit used by a small to medium business, carried out in an industrial area, processing the waste of that business and perhaps of businesses around them into fuel that would supplement their fuel requirements.
One thing we can be sure of is that fuel prices are going to increase in the future and any fuel intensive business is going to find a source of cheap diesel a powerful competitive edge over their competitors.

[Beyond Biodiesel]

Taking the potential risks involved in hydrocarbon cracking Im not sure this could ever be an activity carried out in a typical suburban house.
Im a organic gardener myself and an enthusiast for home composting but there is very little risk of my composter exploding and burning my house down.
I see it more as a unit used by a small to medium business, carried out in an industrial area, processing the waste of that business and perhaps of businesses around them into fuel that would supplement their fuel requirements.
One thing we can be sure of is that fuel prices are going to increase in the future and any fuel intensive business is going to find a source of cheap diesel a powerful competitive edge over their competitors.

You make good points, imakebiodiesel. There are certainly other methods for recycling waste oils into diesel fuel, that are safe to employ. For instance I blend gasoline with WVO or WMO and it works great to make diesel fuel. I have far more waste oil available to me than I need, so I see no reason to do back flips to build a retort in my yard to make diesel fuel.

However, I am interested in finding other ways of making my own diesel fuel in case my waste oil sources dry up. And, the source I am most interested in is extracting terpenes out of resinous woods. I am most interested in that for various reason: it is low toxicity, waste wood product everywhere, and even my exhaust smells like a forest.

It just so happens that the same methods for cracking waste plastic into diesel fuel can be used to extract terpenes. Extracting terpenes is far less toxic, and no where near as potentially explosive. And, the whole process could be fueled by the spent wood particles after terpene extraction.

[batwicho]

insufficient heat

I made a new reactor h = 1,10 r = 0,125 V = 0,053 m3 (53 lit) heated with propane-butane burner with a capacity of 9 kW for 4 hours only gas ... some advice ...?

[imakebiodiesel]

Batwichco, we need more information to be able to give you advice. What plastics did you use? What size of batch? HWhat temperature did you go to in the reactor? Do you have a reflux column?, What catalyst if any did you use.? What kind of condenser do you have?
Im going to put an idea out there for discussion. Please note that this is not a recommendation. What about purging the reactor with propane? Before you gasp in horror let me explain. The idea is to begin purging at the same time as starting to heat the reactor. My reactor heats up slowly and takes an hour before reaching cracking temp 385C. The propane would be fed into the reactor passing out through the column and condensers and the bubbler and then mixed with the regular propane feed to heat the reactor. Once cracking starts the propane can be turned off or at least turned down. When the output of hydrocarbon gas subsides at the end of the batch the propane feed can be increased again.
One advantage of this system is that you would get the purging gas for free since it would all be used to heat the reactor.
Propane can be obtained almost anywhere in the world whereas Argon, CO2 or nitrogen can be difficult and expensive to get.
Propane is no more dangerous than the hot hydrocarbon gases that the reactor is designed to handle.
Comments please.

[Excalibur]

I made a new reactor h = 1,10 r = 0,125 V = 0,053 m3 (53 lit) heated with propane-butane burner with a capacity of 9 kW for 4 hours only gas ... some advice ...?

More information please. Did the reactor reach 400C? How about some pictures? Thanks.

[sixth sense]

condenser design

Sorry sixth sense, you picked up my post wrong, i was asking if it is suited as a reactor chamber & was advised most likeley for WMO only & not plastics.

Uncorruptable,

I was having some research on properties of the gases resulted from melting plastic, with very limited info.Even property of diesel on various pressure and temperature and phases.

But with the small amount of data I found on the internet

here is a good estimate on the mass of water to cool down a hot "plastic vapor" from 400C to 200C

M=m*(28,000)/(dT)

where m is the mass flow rate of vapor and dT is the design delta of water temperature (Tout - Tin),

If you have a gas flow of 1Kg/Hr and water Tin=20C and Tout=80 (avoid vaporizing the water since it will eventually clog your piping system if the water you use is not treated)

M=1*(28,000)/(80-20)=467Kg/Hr

Since heat exchanger, such as condenser, are not 100% effecient, need to add more factor on that between 10%-20%

This will help decide the the size of the pump to use, the size of the condenser


if you are reducing the vapor temperature from 400C to the other temp other than 200C, this may not be applicable.

for 400C to 130C

M=m*(34,000)/(dT)


The assumption here is that the vapor from melted plastic contain mostly of diesel vapor, which is not true but a good estimate.So the vapor after the first condenser which probably contain less diesel will have a entirely different values .

[Beyond Biodiesel]

Im going to put an idea out there for discussion. Please note that this is not a recommendation. What about purging the reactor with propane? Before you gasp in horror let me explain. The idea is to begin purging at the same time as starting to heat the reactor. My reactor heats up slowly and takes an hour before reaching cracking temp 385C. The propane would be fed into the reactor passing out through the column and condensers and the bubbler and then mixed with the regular propane feed to heat the reactor. Once cracking starts the propane can be turned off or at least turned down. When the output of hydrocarbon gas subsides at the end of the batch the propane feed can be increased again.
One advantage of this system is that you would get the purging gas for free since it would all be used to heat the reactor.
Propane can be obtained almost anywhere in the world whereas Argon, CO2 or nitrogen can be difficult and expensive to get.
Propane is no more dangerous than the hot hydrocarbon gases that the reactor is designed to handle.
Comments please.

Using propane as a purge gas has some merit, as you said, you are directing the flow to a burner so you burn your purge gas, as well as any butane, propane, or methane that will definitely be a by-product of cracking.

However, using a flammable purge gas does not solve the basic problem of what do you do, when you turn off the heat, and gasses in the retort start condensing and drawing air in from the exit of the condensers, and that air meets hot hydrocarbons in their vapor phase at a 4:1 ratio? Because that equals ignition.

Uncorruptable,

I was having some research on properties of the gases resulted from melting plastic, with very limited info.Even property of diesel on various pressure and temperature and phases.

But with the small amount of data I found on the internet

here is a good estimate on the mass of water to cool down a hot "plastic vapor" from 400C to 200C

M=m*(28,000)/(dT)

where m is the mass flow rate of vapor and dT is the design delta of water temperature (Tout - Tin),

If you have a gas flow of 1Kg/Hr and water Tin=20C and Tout=80 (avoid vaporizing the water since it will eventually clog your piping system if the water you use is not treated)

M=1*(28,000)/(80-20)=467Kg/Hr

Since heat exchanger, such as condenser, are not 100% effecient, need to add more factor on that between 10%-20%

This will help decide the the size of the pump to use, the size of the condenser


if you are reducing the vapor temperature from 400C to the other temp other than 200C, this may not be applicable.

for 400C to 130C

M=m*(34,000)/(dT)


The assumption here is that the vapor from melted plastic contain mostly of diesel vapor, which is not true but a good estimate.So the vapor after the first condenser which probably contain less diesel will have a entirely different values .

Interesting and useful calculations for how much water one needs in a condenser stream. I find my little pilot plant does not need much water flow to cool the vapor. The thing I have noticed is regardless of how cool I make my vapor stream oil mist will still come out of my exhaust. So, I have been working on distillation column packing.

I have used a twisted aluminum strip

The braided shield from coax cable

Copper choir boys

Aluminum chips from a machining

and rolled up aluminum bug screening. All of this packing seems to work, but it does not get all of the vapor out of the stream, so I put a big-blue-water filter at the end with a 20-micron pleated cellulose filter in it to act as a kind of air-filter to which the oil vapor will wick to, and if enough oil condenses upon the filter, then it will run off and can be drained with a tap at the bottom of the filter.