the fuel oil (FO) of different grades (Sulphur: 3-3.5 wt %) is prepared by
blending of following streams to meet viscosity and sulphur:
Lighter stream (light cycle oils/other cracked
Heavy stream (vacuum/visbreaker residues, cat
cracker slurry oils)
oil desulfurization economics
petroleum streams (gasoline and diesel) are desulfurized in a fixed bed reactor
system, which are not suitable for processing FO. In refineries with existing
process units, FO desulfurization even to 5000 ppmw sulphur level is not
desulfurization to 5000 ppmw sulphur, requires heavy oil hydro-desulfurization
facility, which includes Ebullated and Slurry based technologies. However, due
to requirement of significant amount of hydrogen and high pressure operation
(more than 120 bar g H2 partial pressure), the process is cost
ballpark cost estimate for a 1 MMTPA FO desulfurization unit (from feed sulphur
of 3 wt % to 0.5 wt %) is around Rs. 2000 Cr. However, this unit also requires
other accessories, viz. hydrogen generation unit, sulphur recovery unit,
off-site plants, etc. Hence, the estimated cost for a FO desulfurization
complex is around Rs. 3000 Cr. The typical operating cost for a 1 MMTPA unit is
around Rs. 4500 per Metric Ton. The estimated cost for production of 5000 ppmw
FO is around Rs. 40 per liter. However, the cost of production for BS IV Diesel
(50 ppm) is around Rs 30 per liter.
view of the above it is better to use BS IV Diesel (50 ppm) instead of 500 ppmw
sulfur containing FO.
the best of our knowledge, currently no commercial technology is available for
desulfurization of FO from current sulphur levels of 3 wt % to 500 ppmw (i.e.
Annex 2. Impact of using BS VI fuel in BS IV engine
Impact of using BS VI fuel in BS IV engine
vehicles and BS IV fuels in lower vintage vehicles
Oil Corporation Limited (IOCL)
August 2017, New Delhi
VI fuels offer significant improvements in terms of performance, emissions
& durability of BS IV and Pre-BS IV vehicles.
DIESEL: The comparison between the
BS IV and BS VI diesel fuel is given in Table A2.1. Few fuel specifications
have been revised in BS VI as compared to BS IV. The effect of these changes on
BS IV & older vehicles are as follows:
Sulphur: In BS VI, the sulphur content of
diesel is reduced to 10 ppm from 50 ppm in BS IV. Decrease in sulphur level
will reduce corrosion and engine wear related issues; this would essentially
increase the life of the engine. The sulphur reduction will also reduce
sulphate formation and related exhaust particulate matter (PM) emissions. Low
sulphur fuel allows the use of advanced exhaust catalysts for emission control
and enhances their durability.
PAH: Reduction of PAH content of diesel fuel offers the
benefit of significant decrease in both oxides of nitrogen (NOx) and PM
emissions. Further, the carcinogenic PAH emissions in the exhaust will also be
FAME (Biodiesel) Content: BS VI specification allows
blending of up to 7% biodiesel in diesel. The addition of biodiesel would
reduce the CO, HC and PM emissions significantly. In general, biodiesel has
superior lubricity characteristics compared to normal diesel, which would
improve the life of the fuel system components and engine.
GASOLINE: The comparison between the
BS IV and BS VI motor gasoline is given in Table A2.2. There are certain
parameters namely distillation (E70), sulphur, Reid vapour pressure (RVP),
Vapour lock index (VLI), Gum, Oxygen content and ethanol content were revised
in BS VI compared to BS IV. The effect of these changes on BS IV and older
vehicles are as follows;
Sulphur: Studies indicate strong correlation
between fuel sulphur with HC and PM emissions. It enables the use of more
advanced technologies for emissions reduction and fuel efficiency. Further,
like diesel, low sulphur gasoline improves the performance of engine and
efficacy & durability of after-treatment devices.
Gum: The gum content is reduced to 4 mg in BS VI compared to 5
mg in BS IV. The reduced gum level decreases the formation of engine combustion
chamber deposits leading to higher fuel economy.
E70, RVP, VLI, Oxygen content and Ethanol content: The fuel parameters such as
E70, RVP, VLI, Oxygen content were revised in BS VI gasoline specification to
allow ethanol blending up to 10%. The blending of ethanol offers significant
benefit in terms of HC and CO emissions. However, E10 blends results in average
fuel economy penalty of ~2% on account of lower calorific value (~3.5%).
Internationally, to begin with, a practice of differential taxation was
followed wherein an appropriate tax credit used to be given to the customer
opting for environment friendly fuels Such initiatives may enhance the use of
bio-ethanol for blending thereby; decreasing the dependence on fossil fuel
imports leading to significant savings in foreign exchange.
Possibility of advancing the availability BS VI fuels in Delhi
and NCR region and the cost implications thereof:
The present annual Diesel and
MS demand in Delhi and NCR region is as 6200 TMT and 1980 TMT respectively,
while at present the annual capability of both PR and MR to produce BS VI
compliant Diesel and MS is only 220TMT and 385TMT respectively. It is pertinent
to note that the BSVI projects for both the refineries are getting completed by
end 2019 and hence, in view of this timeline it will be difficult to cater to
the demand of Delhi NCR region by BSVI compliant fuels prior to the April 2020
However, already IOC has
commenced supplies to auto majors for engine testing purposes BSVI compliant
fuels from Matura Refinery. Moreover, supply of limited volumes of BS VI
gasoline and diesel are already being explored at select RO’s in major metros
on the request of the Automobile manufacturers.