Kazanorgsintez expands feedstock base
A project that can be an example for new ethylene plants across Russia was implemented in Kazan. The work Joint Ethane and Propane Technology Development and Industrial Use of a Complex of Technical Solutions for Using the Technology in Pyrolysis Units at Kazanorgsintez PJSC including the stages of development of scientific bases and practical implementation of the project was declared as a candidate for the State Award of the Republic of Tatarstan in science and equipment. In an interview, Vice Chief Engineer of Kazanorgsintez PJSC in science and development, Doctor of Technical Sciences, Professor Damir Safin talked about the implementation of the project and how to adapt pyrolysis units for different raw materials and why this is needed.
“It is the most eco-friendly and harmless technology of all known”
Mr Safin, a big research project that lasted for several years ended at Kazanorgsintez PJSC last year. Its results were used in a real plant. What is the project about?
Yes, last year, we completed the implementation of a project to use an alternative feedstock to ethane — propane — in pyrolysis units. The project was developed and implemented from 2013 to 2020. During the implementation of the project, joint ethane and propane pyrolysis technology was created, these units were modernised. In fact, we upgraded and adapted pyrolysis equipment that was initially built to operate with ethane to working with propane. Now, thanks to the new feedstock, we can fully load the capacities and increase ethylene output.
Kazanorgsintez is a unique enterprise for Russia because it runs on ethane as feedstock. Is such technology in demand today?
Kazanorgsintez is indeed the only company on the territory of Russia to use ethane-based ethylene production technology that is then used to make different polyethylene brands. From an environmental point of view, it is the most eco-friendly and harmless technology of all known nowadays. The economic efficacy of ethane processing compared to heavier feedstock — straight-run gasoline or liquefied hydrocarbon gases — is much higher. Ethylene is the main product of ethane pyrolysis. No more than 15% of methane and hydrogen is made, up to 80-82% of ethylene is manufactured. This equipment doesn’t have units for additional processing of heavy pyrolysis products, which significantly simplifies the layout of the pyrolysis unit. Consequently, capital construction costs of ethane pyrolysis units are much lower than pyrolysis units for other feedstock.
Therefore pyrolysis capacities based on gas, primarily ethane, are now developing around the world. This area remains in demand in Near Eastern countries and the USA. A petrochemical boom conditioned by the Shale Revolution in the USA with a big surplus of cheap ethane as a result was a sudden stimulus for its development. It became the feedstock to create big production capacities for refining.
Why was it then necessary to shift your enterprise to another raw material?
A large-scale production development programme was implemented in the early 2000s after Kazanorgsintez joined TAIF Group. The ethylene complex was upgraded too. The total installed capacity of ethylene units rose from 400 to 640,000 tonnes of ethylene a year. However, real supplies of this feedstock didn’t meet our needs.
Nowadays Russia has two key ethane manufacturers. It is Orenburg Helium Plant of Gazprom PJSC and Minnibayevo Gas Processing Plant of Tatneft PJSC. Our ethane pipeline receives ethane from both enterprises and consumes all the ethane they make. The ethane production potential is limited in Russia today. This is why we had to make the production more flexible from a perspective of feedstock.
How did you do it?
Within the developed project, it was offered to use propane as an alternative raw material to ethane. Regarding its characteristics, propane is a liquefied hydrocarbon and is the closest product to ethane. The main task of the creation of the joint ethane and propane pyrolysis was to select optimal conditions for the mixed feedstock pyrolysis, considering the characteristics of these products. The optimal ratio of ethane and propane, pyrolysis temperature providing the biggest ethylene production with the biggest feedstock processing was found.
“We call the development ‘flexible’ joint pyrolysis technology”
What is the essence of the joint ethane and propane pyrolysis technology?
We call the development “flexible” joint pyrolysis technology. The technology is based on the use of mixed feedstock with a limited content of propane in pyrolysis.
Our unit was designed for pyrolysis of pure ethane. Given that the ethane pyrolysis furnaces were not fully loaded, the idea of using mixed feedstock came to our mind. There was done modelling, and propane pyrolysis and joint ethane propane pyrolysis were calculated for ethane pyrolysis furnaces. The calculations proved the feasibility of such a solution. Also, there was proved the possibility of using ethane pyrolysis furnaces for pure propane pyrolysis too.
For practical use, we chose two variants of using propane feedstock in ethane pyrolysis units: it is the constant use of mixed feedstock containing up to 15-20% of propane and use of pure propane in pyrolysis furnaces during repairs in the ethane pipeline or repairs in our suppliers’ ethane units.
Now the project is over and used in production. Why did it take seven years?
Two reasons explain such duration. Firstly, a huge amount of work, including the simultaneous research itself, design, purchase of equipment and assembly works, was done during this period. Secondly, key works on equipment assembly were done for short periods of time during annual major equipment repairs. It is physically impossible to do anything when current units are operating.
During the practical implementation of the project, six new pyrolysis furnaces, a “cold” unit of the equipment were built. It provided pyrolysis gas processing made by using the alternative feedstock through pyrolysis. Also, we upgraded compressors and ethylene and propylene production columns, reconstructed and replaced heat exchangers, built a new desalinated water treatment unit to meet the needs of pyrolysis furnaces.
Can we already say how successful this project is?
We can, of course. Firstly, we proved the possibility of joint ethane and propane pyrolysis with a limited maximum content of propane in pyrolysis feedstock. Secondly, we can certainly say that a rise in ethylene production is seen in joint ethane and propane pyrolysis, which already allowed us to cut key feedstock consumption, which is ethane. Thirdly, the possibility of using pure propane in operating pyrolysis furnaces designed for ethane was practically proven. During the periods of limited supplies of ethane from our suppliers, this solution has been successfully used in the pyrolysis units and providing ethylene output with the alternative feedstock since 2018.
The results of the project are also echoed in the financial performance of the enterprise. So from 2013 to 2020, more than 650,000 tonnes of propane were additionally processed in the pyrolysis units of Kazanorgsintez. The amount of additional revenue from sales of different polyethylene brands made by processing additionally manufactured ethylene reached over 21 billion rubles. Consequently, taxes to all budgets rose.
How applicable are your developments in other industrial projects that are implemented on the territory of the country?
The practical use of the technology shows that it allows improving technical and economic indicators of ethane pyrolysis. We think the gained experience can be useful for re-created ethane pyrolysis units in enterprises and Amur Gas Chemical Complex (SIBUR Holding PJSC), Baltic Chemical Complex (Gazprom PJSC and RusGazDobycha JSC), Irkutsk Oil Company LLC.