Courtesy of oilandgastechnology.net

The world's gas fields are mostly contaminated with carbon dioxide (CO2), hydrogen sulphide (H2S) and other impurities. Current treatment technology for removing the sour toxic compounds, however, mainly relies on large and energy intensive sweetening units to treat the gas to ensure that it meets market standards.

Such a method got Mohamed Al-Marzouqi, Professor of Chemical Engineering at UAEU and Director of the University’s Emirates Centre for Energy and Environment Research, and Sayed Marzouk, Professor of Chemistry at UAEU, thinking. Together, the duo started exploring an alternative membrane-based treatment method.

Al-Marzouqi explains. “We developed a new membrane-based technology to capture carbon dioxide from natural gas which currently is done – or at least mostly done – by what they call a sweetening unit. In one unit, sour gases are captured using some kind of solvent; and in the other unit, the solvent is regenerated for reuse. Now, we use the same technology but instead of using large sweetening units we use a small membrane-based treatment to provide an alternative compact technology making it ideal for offshore plants.”

Furthermore, Al-Marzouqi says: “Sweetening units use lots of energy – in fact most of the energy consumption is used for the regeneration of these solvents. Our technology – which relies on large number of small porous polymeric tubes – uses much less solvent, ultimately reducing the amount of energy needed in the regeneration part of the process.”

“In the lab we developed conditions that were like what they have in the field – in terms of high temperatures and pressures.  A lot of work went into making sure that we not only met the target using a different technology but that we were working in the same conditions.

“We tried to reduce the solvent usage because our target was not only to see if we could meet the target but to determine how much less solvent we could use. Based on this we could calculate how much energy we could save. Once we could get these conditions right – and these were very severe conditions that don’t usually work together; very high temperatures, high pressure and toxic gases – we knew we could take it further.”

It doesn't stop there. While the professors were working on the membrane-based treatment, they noted the high capital and maintenance cost of the commercial hydrogen sulphide and carbon dioxide analysers.

“Currently the available devices to measure CO2 and H2S are very expensive,” adds Al-Marzouqi who, together with Professor Marzouk, started developing analysers for measuring the concentrations of both compounds. After several years of intensive research, the duo’s Aha! moment finally came.

“This is smaller, lighter and cheaper to manufacture,” explains Al-Marzouqi. “With this, you can have an analyser based on a miniature sensor for a fraction of that budget. You just supply the gas stream and measure the concentration.”

Source: oilandgastechnology.net