PRETACA - Production of ethylene and acetic acid by oxidative dehydrogenation of ethane

Motivation

Of all the relevant basic chemical production processes, steam cracking is the most important petrochemical manufacturing process to produce basic chemicals such as ethylene, propylene, butadiene and benzene. Steam crackers emit very high amounts of CO₂ in the range of approx. 0.76 tons of CO₂ per ton of product. Alternatively, more efficient processes for ethylene production can therefore open up a large potential for CO₂ savings.

Research Objectives and Approach

One such alternative process is the oxidative dehydrogenation of ethane (ODHE), a catalytic process in which acetic acid is produced as side product in addition to ethylene. Due to the exothermic nature of the partial oxidation at the associated mild reaction temperatures in the range of 300-400°C, process concepts are feasible for the ODHE that enable largely CO₂ -neutral (regarding scope 1 and scope 2 CO₂ emissions) ethylene and acetic acid production.

The development of such CO₂-minimized process solutions is a research objective in this project. With ODHE technology, the ratio of the valuable products ethylene and acetic acid can also be adjusted. However, there is also a need for additional research and another goal of the project: on the one hand, the overall product yield is to be increased significantly, which is equivalent to minimizing direct CO₂ emissions, and on the other hand, the range of the adjustable ethylene-acetic acid ratio is to be significantly expanded. The ODHE technology could not only be considered as a substitute for the established steam cracking process, i.e. producing negligible amounts of acetic acid, but can also be seen as new process for further downstream production processes, such as the production of vinyl acetate monomer, in the case of production of high amounts of acetic acid.

Overall, the research work is based on four pillars:

1. Increasing the total product yield of ethylene and acetic acid and thus directly minimizing the by-products CO und CO₂.

2. Process intensification by developing concepts for maximum energetic process integration.

3. New concepts for the purification of input and product streams. This also applies to the catalyst manufacturing.

4. Research on alternative concepts for substituting established process infrastructure with alternative process steps and the integration of renewable energy. This also includes the development of the integration of the ODHE process with subsequent processes on the one hand and in existing stream crackers for their capacity expansion on the other hand.