Bez nadpisu - Česká rafinérská, as

Bez nadpisu - Česká rafinérská, as

Processing of VGO at the NHC

Unit in the Litvínov Refinery

Jiří Hájek

Česká Rafinérská a.s.

February 2008 1

History of Hydrocracking

in Litvínov

1940’s High-pressure

hydrogenation plants to process

derivates from brown coal using

German technology (Bergius –

Pierry process).

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

cracker plant.

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

1st reactor

2nd reactor

pretreatment Ni-Mo catalyst hydrocracking zeolite catalysts

inlet temperature

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

Revamp I

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

Revamp II

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

(Shell technology).

Achieve a minimum cycle length of 24 months in the high

conversion mode.

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

Feed pump:

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

2,6 v/v/hr

4,2 v/v/hr

Total Recycle Gas / Oil ratio 1130 Nm 3 /m 3

Pressure HPS

15,2 MPa

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:

Pretreatment catalyst

Hydrocracking catalyst

KF-848 1.3 Q


February 2008 16


Unique opportunity

Increased conversion

Increased diesel make

Better utilisation of both refineries

Minimal HFO production

Adequate cost level

February 2008 17

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