* Destination clause for crude a sticking point
* Trade so far largely limited to oil products
* Chinese teapots slow to soak up Trafigura's Iranian crude cargo
* For other news from the Reuters Global Commodities Summit, click here
By Julia Payne and Ahmad Ghaddar
LONDON, Oct 13 Nine months after sanctions on Iran were lifted, some of the world's biggest traders have yet to strike major oil deals with the OPEC member, stymied by Tehran's tough stance on marketing its crude and restrictions on dollar trades.
Top executives from Vitol, Glencore, Trafigura and Gunvor told the Reuters Commodities Summit this week that while they are keen for a slice of the business, hurdles remain.
"It's still very difficult," Ian Taylor, chief executive of commodity trading house Vitol, said.
He cited the lack of a usable dollar system to conduct transactions with the country, making transfers of the U.S. currency troublesome and hindering trading.
Taylor said that while Vitol had started to do some business with Iran, the competition was strong. "Everybody is looking at it as well."
Most Western sanctions against Iran were lifted on Jan. 17, but remaining U.S. restrictions stipulate that only non-U.S. banks can do dollar trades with Iran provided these do not pass via financial institutions in the United States.
Iran has already signed a raft of deals with international firms, some of which are dollar-based. But to date big banks have steered away from doing business involving the country, out of worries over inadvertently running afoul of U.S. authorities.
Concerns about the dollar were echoed by Gunvor Group Chief Executive Torbjorn Tornqvist and Trafigura Chief Financial Officer Christophe Salmon.
Limits on where crude can be sold remains a sticking point as it reduces a trader's ability to maximise profit margins, particularly in an oversupplied market.
"We shouldn't also forget that the Iranians ... when it comes to crude oil, are extremely skilful in their marketing," Tornqvist said.
"They need to know where it (crude) goes and to whom. And we see very little change: 'this is what we did before sanctions and this is what we'll continue to do after the sanctions'."
Iran, like Saudi Arabia, sets different monthly prices for each region and has traditionally dealt only with majors or pure refiners where supplying their own refineries remains the core business.
Trade houses have been largely confined to Iran's refined products market although Trafigura loaded a large cargo with Iranian crude in late June.
"Iran is a very promising country for many companies including ourselves. But so far what we have done since the sanctions were lifted, it's really small," Salmon said.
Trafigura loaded the Olympic Target tanker with 2 million barrels of Iranian Heavy crude in a bid to capture market share among China's independent refiners.
But the so-called teapot refineries were slow to buy the oil once it arrived in China. After arriving in the area around mid-July, it took the tanker a month and a half to start offloading, Reuters ship tracking data showed.
Global head of oil at Glencore, Alex Beard, said his firm had already had substantial dialogue with Iran, including "conversations with NIOC about prefinance and continue to talk to find the right terms and conditions for both sides".
But so far Glencore has only bought Iranian oil products from the National Iranian Oil Company (NIOC) and private sector players.
While Iran has publicly stated that it wants to reinstate a system whereby it swapped oil from the Caspian Sea region for crude loading in the Mid-East Gulf, Vitol remains lukewarm. [here ]
"It's an incredibly difficult trade to make if you think about it and there aren't huge volumes available in the Caspian anyway," Taylor said. "I would be a little bit sceptical that the swap will start any day soon even though technically it can." (Editing by Susan Thomas; Follow Reuters Summits on Twitter @Reuters_Summits)
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UPDATE 1-Police arrest man, but say London airport incident not "terrorist-related"
LONDON, Oct 24 British police said on Monday that they had arrested a 25-year-old man in connection with an incident that led to the evacuation of hundreds of passengers from London City Airport on Friday, but that the matter was not "terrorist-related".