Specialists from the National Ecological Company (Yaroslavl), together with researchers at the NSU Natural Sciences Department Physical Chemistry Section and the NSU-NNSC Accelerator Mass Spectrometry Center, are creating technology for producing fuel from non-recyclable plastic.
NEC Development Director Alexander Klimov talked about this work,
During waste sorting, a large amount of non-recyclable plastic remains. As a rule, this is a mixture of ordinary contaminated thin films (T-shirts, shopping bags) and illicit plastic that is contaminated or mixed. Currently, all this is burned, or, at best, sent to cement factories to replace natural gas. The national project “Ecology” and regional regulations mandate that this plastic be removed from landfilled waste. However, so far no one has a global solution on what to do with it.
The National Ecological Company decided to try to convert this plastic into environmentally friendly motor fuel. The technology developed by NEC specialists consists of several stages. The first stage is pyrolysis, thermal destruction without oxygen. It is carried out at temperatures from 400 to 600 °C. The output is a heterogeneous mixture of hydrocarbons containing a large amount of impurities and aromatic compounds. During the process of thermal destruction, thousands of chaotic chemical reactions occur and at this stage it is impossible to guarantee the target product will possess coherent properties.
Then rectification is conducted - the process of separating binary or multicomponent mixtures due to mass transfer between steam and liquid. At this stage, the mixture breaks down into fractions and boiling point. And although the resulting product is much cleaner, it still cannot be used as fuel. The high content of unsaturated hydrocarbons makes it reactive, which leads to the failure of internal combustion engines. In addition, just standing in the air this fuel oxidizes quickly. If at first it is yellow and transparent, after a few weeks it becomes resinous.
Pyrolysis and further purification is a fairly common method of processing; it is widely used in Russia and around the world. The challenge is how to get from this low-quality and rather unpredictable fuel to something that can be poured into the gas tank of a car or even into an airplane.
This requires catalytic technology, which NEC representatives asked researchers from NSU to develop.
Ekaterina Vorobyova, Junior Researcher at the Accelerator Mass Spectrometry Center, provided more details,
We proposed starting the first experiments with common and well-known systems, nickel-molybdenum catalysts on an aluminum oxide support. They managed to obtain the first positive results. However, since the process is carried out in microchannel reactors—steel capillaries with a diameter of about a millimeter—this imposes its own limitations on the preparation and operation of the catalyst. In the future, we plan to sel ect parameters that will make it possible to obtain high-quality synthetic fuel and optimize the technology.
In the beginning, NSU scientists proposed technology parameters, loading, ratio of inert material, and catalyst. The new technology has passed its first tests at the NEC pilot plant.
Klimov described the system,
The catalytic system maintains a temperature of about 300 °C and high hydrogen pressure and hydrogenation of the mixture occurs. The output we received was a transparent liquid with the mild smell of motor fuel and almost zero sulfur content, suitable for use in internal combustion engines.
There is still much to be done. First, it is necessary to once again modify the hydrogenation plant so that it can operate stably for more than 1000 hours. Secondly, it is necessary to work out all the automatic catalyst regeneration cycles and think through all the complex technical solutions. In addition, it is important to select optimal parameters for the catalytic process. To achieve this, a laboratory version of the reactor will be sent to the Natural Sciences Department Physical Chemistry Section.
Parameters include temperature, pressure, catalyst fraction, and, possibly, even its composition. We need to select conditions for the most efficient and long-lasting process.
NEC has plans to enter the market. In 2024, they will build a pilot catalytic installation capable of processing kilograms per hour rather than grams. It will be completely autonomous and automatic. An industrial prototype of a pyrolysis system is also being created that is capable of handling a ton of waste in an hour. According to NEC experts, fuel made fr om plastic will have a price advantage compared to other non-fossil fuel sources.
With regard to our collaboration with NSU researchers, we liked their focus on results and desire to solve the problem without spending years to achieve results. And, of course, we appreciated their openness and great internal motivation.