How can GTL technology help produce Clean fuels?

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Stranded natural gas escapes and blazes across venomously every day in parts of Russia, Middle East, and parts of Asia wasting almost 10 billion cubic feet of energy. If this apparently useless gas could be utilized then it could give rise to 1.7 million barrels of oil. Such a huge amount of natural gas, as much as 2500 trillion cubic feet could have easily given rise to another oil rich kingdom. This gas is allowed to escape mainly due to lack of economical ways to transport it. A new technology has been recently developed to turn this stranded natural gas into liquids.

Stranded natural gas escapes and blazes across venomously every day in parts of Russia, Middle East, and parts of Asia wasting almost 10 billion cubic feet of energy. If this apparently useless gas could be utilized then it could give rise to 1.7 million barrels of oil. Such a huge amount of natural gas, as much as 2500 trillion cubic feet could have easily given rise to another oil rich kingdom. This gas is allowed to escape mainly due to lack of economical ways to transport it. A new technology has been recently developed to turn this stranded natural gas into liquids. This process is known as GTL (Gas to Liquid) technology to turn the natural gas into liquid hydrocarbons to be used as fuel for transport. This kind of project can be scalable and optimized in terms of designing the plant so that even smaller gas deposits are easy to convert to oil. It may not be equally competitive as oil producing projects but once the technology evolves in a way to have the liquid transported, it cancompete with oil industries worldwide. However this process should not be confused with the process of producing LNG (Liquefied natural gas). It turns natural gas into synthetic fuels like methanol.

When was GTL technology was first developed?

The process of developing liquid fuel from natural gas dates back to 1923. The process was known as Fischer Tropsch process which is discussed below. This method of producing liquefied synthetic fuel was first developed as a strategy by Germany during World War 2. At that time it was not formulated as a way to lift up the economy but mainly to have an edge above the others. In South Africa the apartheid era also saw the rise of GTL technology. In the year 1985 Mobil from New Zealand developed M-gasoline to make gasoline out of methanol. And this process was implemented at a large scale in a plant. But this resulted in a price rise of more than $30 per barrel and to support the production, huge amount of subsidies from the government was required. In Japan JOGMEC (Japan Oil, Gas and Metals National Corporation) did a lot of research works in the field of GTL technology with five more private sector companies of Japan from the year 1998 to 2004. This was done in order to have an option of exploring stranded gas reserves. It successfully terminated with positive results on the viability options of using GTL technology for liquid synthetic fuel.

How is GTL technology applied to produce liquid fuels?

In the last 50 years lots of techniques have been developed in order to produce liquid hydrocarbons from natural gas. As such it is always possible to synthesize hydrocarbons from any other hydrocarbons. In general we can divide the process of obtaining liquid fuel. A direct conversion from gas is possible and in another method liquid fuel is produced via synthesis gas or syngas from natural gas. The first process is more economically beneficial since an intermediary step of producing the syngas is eliminated. But then it requires a very high amount of energy for activation and it is a little difficult to control. Quite a lot of experimentation has been done on the direct process but none have been economically attractive enough to be commercialized. The indirect conversion is achieved via the process of Fischer Tropsch mentioned above.

• Fischer Tropsch process: This is the method of producing methanol. This uses cobalt or iron based catalysts. The reactor design is vertical and inside the vertical tubes the catalyst is added. The other design incorporates a slurry reactor over which the catalyst is distributed with the help of liquid wax. Upon this the heated syngas is slowly passed. Since this reaction is highly exothermic, that is it generates high amount of heat, this heat should be removed away from the set up. The amount of heat can regulate the distribution of hydrocarbons in a reaction, so it is important to regulate the temperature.

• Syngas : In this process of conversion the natural gas is converted to Carbon monoxide and Hydrogen by partial oxidation. The only thing that can be varied is the Hydrogen to Carbon monoxide ratio. It is recommended that it should be around 2:1 for F-T process. The steam reforming step is done in a fired heater with at least 5:1 Hydrogen to Carbon monoxide ratio. By a swing adoption system the Hydrogen can be removed through a membranous layer to adjust the ratio which can be further used in a refinery for the production of ammonia. Purer syngas can be produced by using oxygen and no nitrogen would be found. In order to obtain the dilute form air is used.

How can GTL technology help?

GTL technology is mainly used to produce fuel used in vehicles with very low emission rates. Due to GTL technology ultra efficient exhaust filters can be designed with higher performance factor. In diesel-electric hybrid vehicles it can be used. Due to its homogeneity in composition, advanced drive train designs can make use of it. More efficient derivatives of the IC (internal combustion) engine can be designed as this technology is developed further. It can significantly reduce noise levels and emissions in an engine. It is very suitable for onboard reforming applications. This can be achieved by coupling it with advanced IC engine technology. Production of hydrogen for fuel cells is also possible. It can also give rise to the process of converting coal to liquid fuel or biomass to liquids with similar chemical composition. Since the liquid fuels produced as a result of GTL technology have high volumetric energy density,  it can be stored easily in lightweight fuels tanks of vehicles to ensure longer distance travel with a full tank.

Which of the three fuels used in GTL technology are more profitable?

For a robust and strong economic analysis, three products manufactured by the GTL technology have been analyzed. The products were DME (Dimethyl ether), FT (Fischer Tropsch) diesel and MeOH (Methyl hydroxide). There were some assumptions made for calculating the financials of the project. The production site of the natural gas is Middle East country. The second assumption stated that the supply site is Korea which is 5000 km away from the production site. DME is sold at the same rate as LPG in South Korea. The land costs and labor involved are all same for all the 3 products. The selling price of FT diesel is $780/ton, DME is $337/ton and MeOH is $561/ton. The exchange rate for South Korea is 933won/$. On the basis of these assumptions the payout period was calculated which states the time period required to recover the money invested on each of the products. On that basis it was found that FT diesel is most profitable, and DME and Methyl hydroxide followed sequentially after that. However the prices may fluctuate since it is dependent on the cost of natural gases.

What are the environmental impacts of GTL technology?

Since GTL technology makes use of useless stranded natural gas which would have otherwise been vented from oil fields as waste gas, it can distinctly reduce polluting gases from being released into the air. It can produce ULSD which is Ultra Low Suplhur Diesel with a very low content of Sulphur in it. It can be blended with other types of fuel to achieve the desired high efficiency. The energy density of the diesel produced by GTL technology can be compared with conventional diesel, but at the same time it has a higher cetane number which ensures ready ignition and efficient burning of the fuel. Since it can be used without the need of any modification of the current diesel engines hence it is convenient as well. The Audi passenger cars use this technology for the fuel to drive the car engine. They have reported that a 93% reduction in the emission of Carbon monoxide and 100% reduction of Sulphur emission is possible as a result of this. Carbon dioxide reduction may not be a huge percentage but 13% reduction is possible and amount of fuel used would also be reduced by 10% as a result of this. A reduction in suspended particulate matter is obtained along with  less amount of aromatics. These have added plus points for reducing carcinogenic agents in the atmosphere associated with respiratory problems.

What are the advantages of the GTL process?

The GTL process would make a market for stranded natural gas, it would be able to pave the pathways for commercialization of the natural gas which is of low value and which was difficult to transport earlier. The price value of the liquefied fuel can very much compete with the ever increasing, sky soaring prices of oil. The fuel would any day be easier to transport than the natural gas. Liquid fuel is easier to pump into vehicle engines than gaseous fuel. The end product obtained after the whole process is of superior quality. The emissions are any day lower than natural gas or any other fossil fuel. So naturally it is a cleaner source of energy. It can also be integrated with the LNG (Liquefied Natural gas) industry. Small and mobile GTL plants can be easily made to make used of small stranded natural gas reserves.

What are the limitations of the GTL technology?

GTL technology, no matter how clean, is actually a non renewable energy. It is dependent on fossil fuels for its production, once these resources are on the verge of extinction, GTL will suffer the same fate as well. The initial cost of setup for running the GTL technologies turns out to be very expensive. In terms of comparison with the existing and new big projects of fossil fuel powered energy, this kind of energy project would get a negative mark. The existing ones are far cheaper. The syngas or the synthesis gas which is one of the intermediate products formed while converting natural gas to liquid hydrocarbons has a low energy value. As a result of all this debt management, project financing can be very difficult for GTL technology projects.

What are the latest developments in GTL technology?

Australia has been making an effort to develop GTL technology in order to promote the utilization of unconventional sources of energy and also to make coal energy clean. Some of the companies which are trying to make this as a viable technology are Carbon Energy, Linc Energy and Beach Energy. As such a lot of works on the economic feasibilty of GTL technologies are being done and the works are still at an early stage. On 29th November 2011, in Tehran, a semi-industrial GTL facility was commissioned by Iran. It is one of the few countries that have taken an initiative to acquire GTL technology. The very first refinery making use of GTL technology would be launched in the near future in the Persian Gulf Islands. This announcement was made by the Oil minister Rostam Qasemi. The production capacity of the refinery would be as much as 10,000 barrels per day. They are specifically concentrating in converting natural gas into value added products like gasoil, gasoline and naptha. Iran would now be interested in exporting refined byproducts instead of crude oil since it is more than self sufficient. It is the second largest producer of natural gas after Russia.

GTL technology can make natural gas a much more feasible fuel. There are trace chances for even coal industries to make their reputation at the cost of GTL technology. As the numbers of cars on the roads are increasing, it is for sure the transportation sector can suffer a heavy setback if cleaner ways of burning fossil fuels are not tried. Due to global economic crisis, natural gas demand declined to quite an extent. But investors were not discouraged as a result of that, and fortunately that has allowed the supply of natural gas in abundance to continue. Hence this new GTL technology should be developed for its clean burning characteristics and higher engine performance for an advanced and clean future.

 

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