Plasma‐based liquefaction of methane: The road from hydrogen production to direct methane liquefaction

Abstract

For the energy industry, a process that is able to transform methane—being the prime component of natural gas—efficiently into a liquid product would be equivalent to a goose with golden eggs. As such it is no surprise that research efforts in this field already date back to the nineteen hundreds. Plasma technology can be considered to be a novel player in this field, but nevertheless one with great potential. Over the past decades this technology has evolved from sole hydrogen production, over indirect methane liquefaction to eventually direct plasma‐assisted methane liquefaction processes. An overview of this evolution and these processes is presented, from which it becomes clear that the near future probably lies with the direct two phase plasma‐assisted methane liquefaction and the far future with the direct oxidative methane liquefaction.

White paper on the future of plasma science in environment, for gas conversion and agriculture

“…A solution to overcome the transportation problem is to convert methane into a liquid product, to avoid leakage and loss of raw materials in gas transport, as well as to contribute to a reduction of the greenhouse effects. To accomplish this purpose several methane reforming technologies have been studied: nonoxidative methane coupling, pyrolysis, partial oxidation, and dry and steam reforming . One of the formed products is syngas, an important chemical feedstock.…”

“…In the last two decades, numerous plasma‐assisted processes have been investigated and proposed for direct CH 4 reforming to added value products . Thermal arc plasma is the only process which has industrially been applied for CH 4 coupling (Hüls process).…”

Applying chemical engineering concepts to non-thermal plasma reactors

“…According to the 2017 Plasma Roadmap [1], 'process selectivity, conversion and/or energy efficiency are still not sufficient to justify the large-scale use of non-thermal plasmas' for many environmental applications. Examples of such applications include the conversion of CO 2 [2][3][4][5], the production of syngas or hydrogen [6][7][8][9], liquid fuels [10][11][12], ozone [13][14][15] or the removal of volatile organic compounds or other pollutants from air streams [16][17][18][19][20][21]. These applications usually involve the use of a plasma reactor where both desired and undesired reactions may take place during or following a non-equilibrium electric discharge, eventually with the help of a catalyst.…”

Pressure as an additional control handle for non-thermal atmospheric plasma processes

“…Plasma reactors are used for a wide range of processes including gas conversion, material synthesis, and surface treatment. The promising technological and economical aspects of non‐thermal atmospheric pressure technology in these areas have recently gained a lot of interest . However, the control and tuning of Atmospheric Pressure Plasma (APP) systems is not trivial.…”