By Al Greenwood
HOUSTON (ICIS)--A future methane-to-ethylene plant using Siluria Technologies' oxidative coupling process could begin start-up by 2017 if the feasibility studies are encouraging, the CEO of the US-based company said on Wednesday.
Already the company has started building its first demonstration plant at Braskem's site in La Porte, Texas − part of a series of agreements that the two companies have reached regarding Siluria's technology.
Siluria and Braskem plan to conduct a joint feasibility study to see if its technology can supply ethylene to Braskem's plants.
Siluria is now having discussions about starting feasibility studies with companies in the ethylene and the gas-processing industries, said Edward Dineen, CEO of Siluria.
If those feasibility studies are encouraging, then front-end engineering and design (FEED) could start by the third quarter of this year, Dineen said. The engineering design would overlap with the start-up of the demonstration unit.
By the first half of 2015, capital could be committed for the first commercial unit, which could have a capacity of 75m-150m lb/year (34,000-68,000 tonnes/year), he said.
On that schedule, operations could start up by the end of 2016 or by Q2 2017, Dineen said.
To evaluate the cost competitiveness of Siluria's oxidative coupling process, it compared the performance of a hypothetical plant against a naphtha cracker and an ethane cracker, Dineen said.
The comparison used US Gulf (USG) prices for feedstock dating as far back as February 2010, he said.
A commercial-scale plant could achieve savings of $1bn/year in capital expense (capex) and operating expense (opex) over naphtha cracking and $250m over ethane cracking, the company said.
In fact, oxidative coupling is competitive as long as the price of 1 bbl of oil exceeds 1MMBtu of natural gas by at least eight times, it said.
The ratio currently exceeds 20.
One of the reasons why Siluria's process is competitive is because it generates heat, which could be used by other units, Dineen said.
Also, oxidative coupling mostly produces ethylene and ethane, so the output is simpler than cracking, he said. This also lowers costs.
For decades, oxidative coupling of methane remained impractical because a high temperature was required before the desired reaction could take place.
To solve this problem, Siluria has employed a novel process – developed by Massachusetts Institute of Technology (MIT) professor Angela Belcher – that uses viruses as a design tool to create a biological template for nanowire catalysts.
The resulting catalysts are about 100 times more active and efficient than previous ones that were considered for oxidative coupling, Dineen said. "You also don't need a lot of it, and it lasts a long time," he said.
To quickly identify the best-performing catalyst, Siluria has developed a process of high-throughput screening. The combination of screening, nanowires and biological templates allowed Siluria to find and develop a catalyst that could make oxidative coupling a practical way to produce ethylene from methane.
The catalyst has lowered the reaction temperature, which eliminates the need for expensive metallurgy.
The availability of the catalyst is not an issue, since Siluria is making hundreds of kilograms, the company said.
Possible uses of Siluria's technology go beyond providing a low-cost source of ethylene, Dineen said.
Ethylene producers could use the process to increase feedstock flexibility, he said.
Smaller methane-to-ethylene units could be built to convert gas that is currently being flared from oil wells, Dineen said. Companies could then use existing technology to covert the ethylene into fuels.
Midstream companies that process natural gas are also potential users of the technology, he said.
For regions with stranded methane, oxidative coupling could give producers one more tool for adding value to natural gas.
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