A chemical engineer may have found a way to make better use of the sulphur surpluses that arise from Abu Dhabi's sour oil and gas reserves.
Saeed Alhassan Alkhazraji is convinced that he has almost everything needed to start a revolution.
An assistant professor at Abu Dhabi’s Petroleum Institute and director of its Gas Research Centre, Mr Alkhazraji has spent the past five years researching processes that will enable him to transform an increasingly important sector in the economy (provided he can obtain a US patent).
The chemical engineer wants to find new uses and applications for the country’s fast-growing and costly stock of elemental sulphur, which is being produced in increasing quantities thanks to reserves of sour, or sulphur-rich, oil and gas.
He believes he has found an answer to increasing sulphur surplus in processes associated with making common plastics.
At current levels, sulphur represents about 2 per cent of the volume of thermoplastic polymers, but he wants to increase this to about 50 per cent.
If he succeeds, Mr Alkhazraji will have found a new commercial application for sulphur that will push down the costs associated with sour gas processing and thermoplastic production.
Sulphur plays a key role in plant nutrition and growth and is the basis for sulphuric acid, the world’s most widely used chemical.
Sulphur is also used in agricultural fertilisers and pesticides, pharmaceuticals and cosmetics, vulcanising synthetic rubber and the surface treatment of steel.
“We’ve worked on 10 polymers so far, including polythene, polypropylene and nylon,” he says of a team that has more than 20 senior, postgraduate and doctoral students.
“The goal is to then create as many applications as possible to help mitigate the issue of the sulphur price, but unlike carbon, which isn’t toxic and from which you can make a lot of applications, the chemistry of sulphur makes it more difficult.
“All of the molecules are either smelly or highly reactive, which means that applications that might increase its price are limited.”
In 2011, the UAE produced 2.2 million tonnes of sulphur, but that figure is predicted to treble next year.
“Sulphur is a big issue for the UAE. When you produce oil and gas in the UAE, it contains high levels of hydrogen sulphide,” Mr Alkhazraji says.
“This is a toxic gas that can be harmful to humans and the environment and has to be converted to elemental sulphur, which isn’t.”
Highly toxic, corrosive and flammable, hydrogen sulphide is present in sour oil and gas reserves at levels between 1 and 30 per cent, but is extracted to produce clean gas using the Claus Process, a method that converts hydrogen sulphide to granular, elemental sulphur.
When the UAE’s reserves of sour gas were first discovered, they were considered too remote and too difficult to process. The gas was simply flared, or burnt off. But thanks to advances in sulphur-processing technology and the UAE’s increasing thirst for clean gas, the processing of sour reserves, such as Abu Dhabi’s Shah field, is now technically and economically feasible.
The largest sour gas project in the world, the US$10 billion (Dh36.7bn) Shah field contains gas that includes 10 per cent carbon dioxide and 23 per cent hydrogen sulphide, both of which have to be removed before gas is considered clean.
At maximum capacity, the Claus Process unit at the Shah field can process about 1 billion standard cubic feet of sour gas a day (scfd), producing about 540 million scfd of gas that is fit for use, and up to 10,000 tonnes of elemental sulphur a day, or 3.65 million tonnes a year. As Mr Alkhazraji points out, this is more than the annual rate of elemental sulphur production for the whole of Japan.
“Right now, sulphur trades at just below US$100 a tonne, but when the UAE produces the elemental sulphur from the Shah field, they will oversupply the market, so logically, the price of sulphur will go down,” the engineer says.
“Lets just say that if you would like to develop another field, you will have to think seriously about it.”
Despite sulphur’s increasing global surplus, market analysts, such as the mining, metals, fertiliser specialists CRU Group in London, predict that rising stocks will not affect the UAE’s production of sour oil and gas.
“Because sulphur is a byproduct with no necessary correlation with demand, it will always tend towards a surplus on a global basis,” says Peter Harrisson, the head of CRU’s sulphur and sulphuric acid team.
“From 1992 until 2002, the market was in surplus every single year, but in the early 2000s the market was in deficit and so the price of sulphur was relatively high in comparison.
“But as of the end of last year and this year, our view is that the market has turned back into surplus and that the price that was nearly $200 a year ago is now below $100.
“Is it important or unimportant to continue the production of oil and gas? I’d say it’s not, but it obviously sits as a revenue stream on its own and many oil and gas producers, including Adnoc, have specific businesses associated with sulphur.
“For those, obviously, it is important that there has been this drop in price now.”
The UAE’s demand for natural gas and the consequent increase in sulphur production is driven, in part, by the country’s increasing demand for electricity that is produced in gas-powered plants.
The UAE also uses natural gas in the enhanced oil recovery techniques that are being used to extend the lifespan of its oilfields.
Sulphur is a naturally occurring, non-metallic element and the 13th most abundant element in the Earth’s crust.
In 2012, only 1 per cent of the world’s 31 million tonne sulphur trade came from mined, elemental sulphur while 97 per cent, known as brimstone, was recovered from sour oil, oil sands and gas of the type found in Abu Dhabi.
But different forms of the element require careful monitoring.
Sulphur dioxide has long been identified as a major cause of acid rain and air pollution and, more recently, sulphur dioxide emissions have been recognised as contributing to the formation of aerosol gases, which can be harmful to the environment and human health.
nleech@thenational.ae
