Annex XII: Membranes as Energy-Efficient Technologies for Separation of Hydrocarbons


Energy saving is seen as the most promising and cost effective option to reduce the use of fossil energy sources. The largest potential for enhanced energy efficiency within the industrial context can be found in the molecular separation processes. These unit operations form the most energy demanding step with the production process. For bulk filtration processes, such as particles from liquids, the energy consumption is relatively low, and this physical separation is fairly simple. However, for molecular separations, more sophisticated technologies are required with an associated much higher energy consumption.

Description of Annex

Distillation, the separation of liquids by evaporation and condensation, is by far the most used separation technique in the chemical and refinery industries, and is also the largest consumer of energy. The exergetic efficiency of distillation is however very low, around 10%. Furthermore, molecular separation technologies are typically responsible for 40-70% of the investment and operational costs. Improvements in separation technology could therefore lead to lower energy consumption and thus to lower operational costs but also to lower capital investments. Molecular membrane separation is seen as one of the most promising and energy-efficient separation technologies. Membranes, partially selective barriers for transport of matter, can reach an exergetic efficiency of 90%. In practice, a reduction of 40-60% of primary energy consumption is anticipated in key molecular separation. However, state-of-the-art membranes and systems are not generically applicable. Membrane materials, modules, systems and processes should be developed hand-in-hand to improve the energetic efficiency of separation processes.

The general objective of Annex XII is to further the utilization of membrane technology in industrial applications. To achieve this, the following aims have been set:

  1. Organization of a discussion platform for dissemination of results in membrane separation,
  2. Bringing more focus to, and setting priorities in the field of energy efficient membrane separations, and
  3. Orchestration of research efforts, in this case with an initial emphasis on olefin/paraffin separation, and natural gas and biogas treatment.

The Annex has identified three Subtasks:

  1. Road mapping and focusing.
  2. Natural gas and biogas upgrading
  3. Olefin/Paraffin separation

Annex status 2012

In 2011 the Annex Management was handed over from the Energy research Centre of the Netherlands (ECN) to the National Research Council of Canada. Despite of broad announcements concerning final definition of Subtask A, the interest in participating in the Annex has been low. Since 2012 there is no longer an active Annex Manager and progress has grounded to a halt. For further information, please contact the IETS ExCo Secretariat.