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Low Sulphur Diesel
in South Africa
A firm decision has been made to reduce the sulphur content in South Africa's diesel from 0,55% to 0,3% by January 2002 - but this will still be higher than the reduced levels of 0,035% in Europe. While a noble goal, the question remains: can it be done? And what will it entail?
Despite the obvious environmental benefits of reducing the sulphur content of diesel there are other considerations, such as whether the process is financially feasible for South Africa's petroleum producers. With the imminent increased use of diesel, commensurate with the intended introduction of diesel-powered taxis in South Africa, a cleaner diesel is going to be an even more sought-after reform. South African Petroleum Industry Association (Sapia) director Colin McClelland explains that diesel with a 0,3% sulphur content is 2c more expensive than 0,55% sulphur-content diesel, and that this increases to almost 10c/l at lower sulphur levels. He states that sulphur content could be reduced even further in the next five to six years. "Certain users, such as farmers for example, may not want to spend another 8c/l to 10c/l when it has no apparent benefit to them, so there is a trade-off between environmental benefits and economic considerations," he points out. Prices will primarily be driven up by several hundred million rands worth of modifications that would be needed at refineries to enable them to produce lower-sulphur-content diesel.
Sapia environmental advisor Anton Moldan explains that the January 2002 deadline has been set by mutual agreement between Sapia, Sasol, the National Association of Automobile Manufacturers of South Africa, the Department of Minerals and Energy, the Road Freight Association and environmental interest groups. "Each refinery has different configurations and, thus, needs different modifications. "However, in general, they will all need to increase their sulphur-recovery capacity by adding hydrodesulphurisation units," he says.He estimates that this will cost about R400-million.
Another option to produce diesel with a lower sulphur content is for refineries to buy different grades of crude oil, explains McClelland. Lighter crude oil has more petrol and diesel, while heavier crude has a higher fuel-oil (tar, bitumen) content, and 'sweet' crude has less sulphur content, while 'sour' crude has more. "Sweet crudes would cost more to buy, but this would be the simplest way to get less sulphur in diesel. "However, this is only the simplest way to move off initially high levels of sulphur content to lower levels to a limited extent, but is not the whole answer for reaching the desired low levels," he expresses. McClelland adds that it is pointless to move the sulphur from the diesel into the environment in the process of extracting it in the refinery.
McClelland adds that another important factor which needs to be taken into account in the diesel debate is whether policy should encourage local refining in the long term, taking into account a move towards more stringent product specifications that require larger investments in equipment from refineries to meet. "Some countries rely more on imported products, while others, such as South East Asia, Singapore and the UK, for example, have regional refining centres. "It would make sense to me that South Africa should continue to have its own refining centre - South Africa's east coast and Durban are logical places. "Advantages of this include foreign exchange savings because, when crude oil is processed at a refinery, the market is saved the foreign exchange expenses associated with imported product. "This could also provide greater security of supply in the event of a tight global market, in that the refinery could compensate if there is a world refinery-capacity shortage," he elaborates. McClelland adds that this could further promote local job creation.
Although refineries create only about a thousand jobs, the maintenance and supply of goods and services could create significant indirect employment opportunities. Along with this come educational advantages, such as the development of chemical engineers and apprentices. McClelland reports that there is currently a study under way - due for completion by March 2001 - to determine fuel quality, with specific focus on sulphur content in diesel, while taking economic considerations into account, in order to determine a way forward. "The position of the industry is such that we are willing to participate in debate to see what the levels are, and industry will not block moves to lower sulphur content, but there needs to be a return on that investment," he stresses.
Sasol technical services manager Raoul Goosen affirms that the costs involved vary from each refinery, depending on its current infrastructure and capacity. "If additional reactors or more hydrogen is needed, then the capital expenditure would be large - costs could vary from a few million to several hundreds of millions of
rands," he reports. Goosen adds that Sasol supported the move to reduce sulphur content to 0,3 %, as it benefits the country to the tune of R800-million. "In the case of the Sasol Synfuels plant at
Secunda, Mpumalanga, the diesel does not contain sulphur and inherently meets the future proposed European levels of less than 0,005 %. "This inherent property makes this diesel sought-after and valuable. "In the case of the
Sasol-owned Natref refinery, no expenditure is needed to meet the 0,3% sulphur level. "For the possible envisaged lower levels of 0,05%,
Natref, along with all the other crude-oil refineries, will require capital expenditure. "However, because Natref already upgrades a more significant portion of our crude oil - due to having an inland refinery and having no marine fuel market - this places Natref in a better position to meet the requirements of producing
lower-sulphur diesel at a more affordable cost," he elaborates. Goosen explains that, although Sasol Synfuels already produces and supplies ultra-low
sulphur-content diesel, and Natref could begin producing 0,3% diesel immediately, due to the lack of financial incentives for the higher value product, Sasol would only implement sulphur reductions according to the timetable that has been set.
While the move to lowering sulphur content in diesel is driven by emission requirements and environmental concerns abroad, in South Africa, the move to 0,3% was largely driven by performance, durability, technological and economic factors and to be more aligned with imported global vehicle technology. Goosen reports that one of the main advantages of reducing sulphur content to 0, 3% is the considerable savings to the users of diesel and, through them, to the country. He explains that, due to the current high sulphur content of diesel fuel, diesel-powered light-commercial vehicles in South Africa typically require servicing more frequently than their
petrol-engined equivalents. This is due to the fact that sulphur is converted to
sulphur-dioxide in the combustion process, which is then diffused into the oil layer coating the cylinder wall and piston rings. The sulphur dioxide then reacts with moisture present in the oil to form
sulphur-type acids which, in turn, are responsible for corrosive wear. Sulphur also contributes to increased particulates (visible emissions) and thickening of the oil. The costs and inconvenience of the additional servicing are, reportedly, a large contributing factor to the unpopularity of diesel-passenger cars in South Africa. Lower engine-wear rates in diesel engines and increased service intervals - along with a reduced effect on the environment from emissions and waste oil disposal - is also
anticipated.
Savings for passenger cars and heavy commercial vehicles, when diesel sulphur content is reduced to 0,3%, is estimated to vary from R550-million to R1,2-billion a year, due to longer engine life and reduced service intervals. This becomes an even more significant consideration when taking into account the government's plans to introduce a new diesel-powered taxi fleet. Despite this, Goosen cautions that the country would not necessarily reap all the benefits by transferring to low levels with the current relatively high age of vehicles. "The country will need to weigh up the benefits and assess how significant they will be to ensure that it gets the best value for the money that is spent," he says.
BP Southern Africa automotive fuels and lubricants technical manager John Fitton reports that, to provide
low-sulphur-content diesel, the company would need to build new desulphurising units to be able to treat the diesel components. "The extent of this expansion would depend on the required sulphur level and other diesel parameters, but would cost more than several million dollars," he says. Fitton reports that BP has planned a shutdown for next year to install the required equipment for the reduction to 0,3% sulphur content. "The planning operation for this is significant, and will take until the end of next year to be ready," he says. Fitton explains that parent company BP Amaco has a global greener-fuels philosophy and supports the move to lower sulphur levels. He reports that BP is motivated by environmental concerns, and will do whatever it (economically) is able to do, to reduce potential harm to the environment. Fitton adds that to reach European levels would require significant spending by the oil industry, along with a cost to the consumer as regards diesel selling price, and would take four years for the necessary equipment to be put in place. "The question is whether European fuel specifications are relevant for the South African economy in general, not as much in capital expenditure cost to the fuel industry, but as regards the benefit to the environment," he says.
Shell Southern Africa fuels technical manager Hans Siemelink reports that the company is committed to achieving the 2002 timetable, and that Shell has been supplying South African mines with low-emission and
low-sulphur diesel fuels for more than ten years. He adds that the move from 0,55% to 0,3% sulphur content requires a lead time and relocation of refinery expenditure - which has accounted for the 2002 deadline. Despite levels in the UK, parts of which currently operate at 0,05% and 0,03% sulphur content, Siemelink reports that such low levels are not automatically being considered for South Africa. "Such low levels in South Africa require significant capital investments - in the order of billions of rands - and an adequate amount of lead time," he points out. Siemelink affirms that the oil industry has agreed to a study, together with other participants, to determine the long-term future properties of diesel and petrol. "A longer-term study, beyond March 2001, between all participants needs to determine what air-quality problems we are trying to solve and how to tackle them, including a relook at lower sulphur levels, along with the other fuel properties of diesel and petrol. "The study will be concluded with a cost/benefit evaluation to determine what is best for South Africa," he asserts. Taking these points into account, it would appear that the days are numbered for dirty diesel, but that debate will continue to rage on how clean and green we should go.
©Martin Creamer Media
Ryan Noik
Engineering News
www.engineeringnews.co.za
Sasol
low sulphur diesel available through most of the newly rolled out Sasol
service stations - check www.sasol.com
for details.
Total also has a low
sulphur diesel equivalent - TOTAL ECO DIESEL PLUS - click here for word doc
data
sheet
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What are the benefits of using
Sasol TurboDieselTM?
The use of Sasol’s TurboDieselä
has the following benefits:
· Improved performance – Due to the cleaner and more
efficient combustion characteristics of the diesel
· Longer engine life – Due to reduced wear
· Extended oil drain interval – Due to reduced soot
formation and lubricant oil breakdown
· Environmentally friendly – Due to reduced harmful
exhaust emissions Sasol TurboDieselTM is classified
as a low sulphur diesel. How does the sulphur levels
compare to other diesels?
In South Africa as from January
2001 the sulphur level in diesel allowed by the
national specification is 0,3 mass % maximum. This
requirement lags behind that applying in first world
countries where most diesel engines are developed.
In Europe for instance the specification was 0,3 %
in 1989 and was reduced to 0,05 % in 1995. Sasol
TurbodieselTM meets the advanced requirement of
vehicle manufacturers by guaranteeing a maximum
sulphur level of 0,05 %.
What are the effects of the lower
sulphur level of Sasol TurboDieselTM?
Sulphur in diesel forms sulphuric
acid that play a major role in increasing engine
wear. When Sasol TurbodieselTM is combusted, far
less sulphuric acid is formed and hence engine wear
rates are significantly reduced.
Sulphur in diesel leads to the
formation of sulphate particulates. In the engine
oil, these cause depletion of the additives and
thickening of the engine oil. Use of Sasol
TurbodieselTM reduces oil breakdown and thickening
and hence engine wear is reduced and oil drain
intervals can be extended. Vehicle tests have shown
that drain intervals can be doubled when Sasol
TurboDieselTM is used.
The sulphate particulates, that
leave the exhaust and that form in the air from
sulphur dioxide emissions, also negatively effect
air quality.
Why is Sasol TurboDieselTM
classified as a low emission and environmentally
friendly diesel?
Sasol TurboDieselTM reduces
harmful exhaust emissions due to its low content of
harmful sulphur and polynuclear aromatics, as well
as its improved combustion properties.
The sulphur level of low emission diesel in South
Africa is a maximum of 0,15 %, versus a maximum of
0,05 % for Sasol TurboDieselTM. This 67 % reduction
gives a proportional direct reduction of harmful
sulphur dioxide and sulphate particulate emissions.
Sasol TurbodieselTM meets and exceeds all the
requirements for low emission diesel according to
the South African national specification. The
content of polynuclear aromatics in European diesel
must be less than 11 %. Sasol TurbodieselTM has less
than 5 %.
Does Sasol TurboDieselTM cost
more?
To refine a superiour low sulphur
diesel, that has properties such as Sasol
TurbodieselTM, costs significantly more. A higher
margin of approximately four cents per liter, that
does not cover such full additional costs, has been
provided for by regulations. However, the pump price
of diesel is not regulated, so the actual price will
vary from site to site. The cost savings of using a
superior diesel, such as Sasol TurboDieselTM , vary
from application to application, but are typically
greater than four cents per liter, so most users
will benefit from demanding Sasol TurboDieselTM.
Do the vehicle manufacturers
advise the use of Sasol TurboDieselTM?
Modern diesel vehicles are
designed for operation with low sulphur diesel.
NAAMSA, representing the vehicle manufacturers,
strongly support the initiative to make low sulphur
diesel available. The specific benefits, such as
extended service intervals, depend from manufaturer
to manufacturer.
Can Sasol TurboDieselTM be mixed
with other diesels?
Yes, Sasol is fullly compatible
with all other diesels. Mixing will improve the
other diesel, so that the quality of the mixture
would be between that of the superiour Sasol
TurboDieselTM and that of the standard diesel.
How can I know if the diesel
that I am buying is Sasol TurboDieselTM?
Sasol TurboDieselTM is dyed purple to enable easy
visual identification.
What are the lubrication
properties of Sasol TurboDieselTM?
Sasol TurboDieselTM exceeds all
international lubricity requirements. A latest
technology lubricity additive is added to every
batch of Sasol TurboDieselTM.
Petrol has an octane rating, but diesel does not.
Diesel has a cetane rating. What is cetane? How does
the cetane of Sasol TurboDieselTM compare to other
diesels?
Cetane is essentially the inverse of octane and
applies to diesel, ie. fuel for compression ignition
engines. The higher the cetane number the easier the
spontaneous ignition (combustion caused simply by
pressure and temperature) of the diesel.
In South Africa the minimum cetane
requirement according to the national SABS
specification is 45. This specification, as for that
for petrols, is agreed by oil companies, vehicle
manufacturers and major users. Sasol TurboDieselTM
typically has a catane number of between 47 and 50.
The benefits of higher cetane number are better cold
starts, smoother running and improved efficiency,
particularly at high engine speeds.
Why is Sulphur in diesel bad for
a diesel engine?
Sulphur in diesel forms sulphur
oxides during combustion, which promotes particulate
formation in the exhaust gas. A reduction in sulphur
reduces this effect significantly. Sulphur oxides
further react with moisture present in the
combustion chamber to form sulphuric acid which
causes corrosion on the cylinder liner and piston.
Low sulphur diesel reduces these phenomena
substantially. This also enables an increase in oil
drainage intervals as basic additives in the engine
oil that sustain Total Base Number (TBN) have a much
reduced depletion rate.
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