History of tyre pyrolysis

I am always amazed when I read that someone writes/posts that they

• have had the first waste #tyre #pyrolysis since 2014.
• have been a process pioneer in tyre pyrolysis since 2015.

I always have to smile here, because the story is a few decades older. But read on!

1981 - Herko test plant

Dr. Rüdiger Schmidt (died 2021), a long-time companion, was involved in these test series at Herko in 1981. Unfortunately, it was no longer possible to determine what was meant by process temperature back then. (See my article Temperatures). However, the final report showed the risks and, above all, the opportunities almost 40 years ago.

1994 - Fuel 1995 Volume 74

In the issue of "Fuel 1995 Volume 74 Number 11 1589" pyrolytic light naphtha from used tires is compared in great detail with petroleum naphtha.

Here, too, several scrubber columns are listed and it is stated that apparently (nearly) no mercaptans are present in the pyrolysis oil...

1995 - CalRecovery Report No 1364

In the middle 1990s, the California Integrated Waste Management Board conducted extensive studies that led to the 145-page final report.

I still find the graph on product distribution particularly interesting. Since the composition of tires has changed somewhat in the last 30 years, the current results will probably deviate somewhat from these values, but they still show a good basis. A detailed flow diagram of a gas-heated pyrolysis system is also shown here on page 30.

2000 - Honmuko test plant

This 120 kg/h plant in Yokohama Dockyards was officially built for contaminated hazardous sewage sludge from the shipyard from TechTrade (CEO Franz-Eicke von Christen ). However, thanks to a larger storage silo, numerous tests could be run for 2 weeks between each batch. Leading chemical engineer was Takeshi Amari, also experienced with scrap tire pyrolysis (Resources Policy 25 (1999) 179–188). Thanks also to Mamoru Araoka for the #MHI project management!

2007 - Czongrad project

In 2007, a project was launched with John (Jack) Fader to replace a waste tire pyrolysis process with 2 batch retort reactors with a continuous rotary kiln pyrolysis process.

In preparation for this, numerous tests were carried out in TechTrade's technical center. The biggest concern was that the rubber material would stick when heated in the rotary kiln, similar to the problems with mixed plastic waste. However, the tests were able to rule out these fears.

Unfortunately, there were problems with the approval process, so the entire project was switched to Limassol and the entire coke refining process was also relocated.

2009 - Limassol plant

In 2009, I set up the system with my colleagues from Techtrade and in August 2009 I personally put it into operation with Christopher Shore and Andrew. Unfortunately, I only received sporadic information from Ahmed & Bogdan Florin Brosteanu .

In December 2023, we received confirmation from the operator in Cyprus that the plant is still running successfully, but we have not yet been able to verify this personally.

2010 - First batch contact...

My sales representative at the time was in contact with a German operator of a batch oven. Since then, we have known that pyrolysis oil from used tires can also reliably breathe movement into an old Golf 2 without any odor (like chip fat).

Unfortunately, the flash point of <22°C is well below the minimum value for diesel. For this reason, it was discussed at the time whether this condensate could also be used as an additive for heavy oil engines.

After a serious accident in which the oven lid flew very high into the air and fortunately did not kill anyone, this path of batch kilns was definitely over. The operating instructions said "You can put whole tires into the reactor." ... Well, with a rim and 2.5 bar?

2011 - HiPo-Award

Based on the experience gained, DGEngineering then developed an initial modules concept, which received the HighPotential Award (HiPo) from the Oberberg/Erftkreis start-up and technology centers in 2011. A critical review was carried out in 2013, which found that there were no critical points.

The plant was the smaller sister of today's MIDI, which, like the Honmuko plant, was still heated with pyrolysis gas, which was the state of the art at the time.

Unfortunately, according to many discussions with potential customers in 2013 and 2014, the throughput rate of 300 kg/h was too low for economical operation, so that a solution for a throughput rate of 1,000 kg/h was required.

2014 - Tyre & Rubber Recycling

Detailed parameters are presented in the magazine "Tyre & Rubber Recycling 2014-02". The conclusion here is:

Perhaps the biggest challenge facing pCB producers is the relatively low volumes of the material being generated, hindering potential validations in high volume/ lower cost rubber applications.

A chicken-and-egg problem: "I'm only interested in buying if you supply me with large quantities!"

2018 - MIDI-Plant

Together with colleagues from Akkodis, the requirements determined to date were implemented in the new MIDI with a nominal throughput of 1,000 kg/h. The objective was and is a modular concept that enables a functional test in the production hall before it travels to the customer.

The challenge for the development of such a system lies in the two worlds, as I described in the article "Fire and water".

The actual thermolysis unit was already emission-free in 2018 thanks to electric heating, paving the way for a #greentech combination of disposal - #circular economy - #hydrogen production.

In addition, there are regulatory parameters that made a redesign necessary in order to have a standard that simplifies the approval process as much as possible and is also suitable for series production. (and also for #plastic)

2023 - Batch HAZOP

We carried out an intensive HAZOP study for a customer with a batch pyrolysis process for used tires, which once again made us very aware of the risks, especially of the batch process.

It is not enough to open the door from the other side to avoid being hit by the door if a deflagration occurs... and a deflagration will occur, as most plants are currently operated.

Conclusio

In the development line alone that I can survey, there are over 40 years of experience in the pyrolysis of used tires in indirectly heated rotary kilns.

In addition, there are hundreds of (very inexpensive) batch furnaces that have been on the market for more than 20 years, but which generally do not meet the safety requirements, with the result that fatal accidents occur more frequently.

At least in Germany, the following regulations apply:

• If a substance with a waste code number (AVV) is processed, then in principle the first thing that comes out at the back is still waste...
• Only when someone wants this carbonate and is prepared to pay for it does it become a product!

rCB is now a very special material for which there is not (yet) a mass market, so it is difficult to get binding acceptance commitments before a plant is built and this risk is usually the knock-out for an investment commitment.

Efforts to achieve standardization (ask Martin von Wolfersdorff ) are helpful here, so that not every project is faced with a chicken-and-egg problem.

Finally

The pyrolysis of used tires is an old technology. The challenge is precisely to operate a safe plant safely and thus achieve economic success and possibly even be a CO2 sink via #PyCCS ...

The realization of a waste tyre project often depends not on the technology, but on the market! As is so often the case ...

Are there any questions? Feel free, to send me an inmail ...