Processing of VGO at the NHC
Unit in the Litvínov Refinery
Česká Rafinérská a.s.
February 2008 1
History of Hydrocracking
hydrogenation plants to process
derivates from brown coal using
German technology (Bergius –
After ceasing of coal processing
units were converted into crude oil
waxy distillates hydrocracking.
Unconverted oil was used as a
lube oil base with excellent
February 2008 2
Currently 2 units operate („old hydrocracker units“) as low
conversion hydrocrackers (40% conversion).
Unconverted oil is predominantly used as feed for an ethylene
4-5 reactors linked in series, using a special catalyst manufactured
on site with higher content of metals (W-Ni). As a carrier
aluminosilicate is used promoted with fluorine.
Units are operated under 225 bar pressure in descending
temperature profile and LHSV 0,75-0,65 v/v/hr. Rate of recycle
gas to feed is 250-300 Nm 3 /t.
Units have been revamped to satisfy the basic safety standards for
this type of unit.
February 2008 3
In 1987 the new modern
hydrocracking unit was put into
Unit was licensed by Unocal as a high
pressure mild hydrocracker using
synergies with the existing steam
Unconverted oil (60% of feed) was
sent to the steam cracker.
Since the yield structure from steam
cracking was very similar to naphtha
feed, the low conversion conditions
resulted in significant savings in
hydrogen and utilities.
February 2008 4
Unit was equipped with 2 reactors
pretreatment Ni-Mo catalyst hydrocracking zeolite catalysts
371°C - 417°C 387°C - 418°C
1,29 v/v/hr 2,04 v/v/hr
ratio of gas to feed
175 Nm3/m3 193 Nm3/m3
Pressure HPS 163 bar
February 2008 5
Situation in the diesel demand in CR
Consumption (2000 = 100 %)
2000 2001 2002 2003 2004 2005 2006
February 2008 6
The first revamp was done in 1999, when the feed rate was increased by
The main reason was to manage for the capacity when a new visbreaker
unit with vacum flasher was built providing an additional feed.
February 2008 7
Dieselization of public transport poses new opportunities.
Forcasted 15 mil t shortage of diesel until 2015 in Europe with naphtha
Dieselization: recalled by environmental protection drives.
Low GHG emission through low fuel consumption.
Ambitious target of automotive industry: 140 gCO 2 /100 km
February 2008 8
NHC x Ethylenecracker
Again unique opportunity in synergy:
Naphtha replacing unconverted oil could be processed in CHP
Jet fuel draw off will bring further incentives.
Unconverted oil originating from higher conversion conditions:
- better BMCI ( better yields, longer decoking periods of the
- it can be cracked ( predominantly) to diesel fuel for market.
February 2008 9
Main technology targets for the revamp :
New fresh feed capacity for the HCU: 60% increase according to
the original design
Conversion increase from 40 – 70%.
Maximum utilisation of available reactor volumes, including use
of new distribution tray and Ultra-Flat Quench sections as options
Achieve a minimum cycle length of 24 months in the high
Production of a kerosene stream.
Maximum middle distillate yield.
February 2008 10
Main modifications reaction section:
New internals to increase the effective volume
available for catalyst in the reactors.
Recycle gas furnace:
Increased duty of the convection bank.
Reactor effluent air-cooler:
February 2008 11
New motor & gearbox
Wash water pump:
New pumps replacing existing ones.
Recycle gas compressor:
Modifications of RG compressor
February 2008 12
Main modifications work-up section
Retraying of debutanizer, fractionator & naphtha splitter:
Kero side stripper installed.
Additional fractionator feed heater installed.
Heat exchanger and pumps modification.
February 2008 13
Main principle of the revamp:
Utilization of the reactor volume.
Developements in catalyst chemistry.
Developements in chemical engineering (new distillation trays).
February 2008 14
New operating conditions:
LHSV hydrotreating catalyst
LHSV hydrocracking catalyst
Total Recycle Gas / Oil ratio 1130 Nm 3 /m 3
February 2008 15
Main process variables:
Conversion (40-70%) – Catalyst utilization, yield pattern.
Feed quality – Content of Sulphur, Nitrogen, CCR.
BMCI of unconverted oil.
MD’s yield & distillation range.
Current catalyst pattern:
KF-848 1.3 Q
February 2008 16
Increased diesel make
Better utilisation of both refineries
Minimal HFO production
Adequate cost level
February 2008 17