The new Schwelgern coke plant

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The new Schwelgern coke plant

                ThyssenKrupp Uhde

Table of contents

Company profile                                           3

Key plant and production data                             4

The “Schwelgern Story”                                 6-7

The Coke-Oven Batteries                                8-9

Innovative Environmental Protection at the Battery   10 - 11

Coke Stabilisation Quenching / CSQ                   12 - 13

Gas Treatment                                        14 - 17

Automation                                           18 - 19

                                                                          Uhde’s head office
                                                                          Dortmund, Germany

1. Company profile
With its highly specialised workforce of more than 4,800 employees
and its international network of subsidiaries and branch offices, Uhde,
a Dortmund-based engineering contractor, has to date successfully
completed over 2,000 projects throughout the world.

Uhde’s international reputation has been built on the successful
application of its motto Engineering with ideas to yield cost-effective
high-tech solutions for its customers. The ever-increasing demands
placed upon process and application technology in the fields of
chemical processing, energy and environmental protection are met
through a combination of specialist know-how, comprehensive
service packages, top-quality engineering and impeccable punctuality.

    Key plant and production data

    Number of ovens       2 batteries of 70 ovens each
    Oven type             Compound oven designed for
                          heating with lean gas and rich gass
    Heating system        Twin-flue oven with air supply
                          in three stages
    Coking time           25 h
    Chamber dimensions    - Length                20.80 m
    (hot)                 - Height                  8.34 m
                          - Width                   0.59 m
    Stack height          150 m
    Machine sets          2
    Oven cycles per day   135
    Coal throughput       10,600 tpd (wet)
    Coke production       2.64 million tpy
    Coke oven gas         155,000 m3/h (STP)
    Crude tar             130,000 tpy
    Crude benzene (BTX)   26,000 tpy
    Liquid sulphur        9,000 tpy

The “Schwelgern Story”

                         Planning of the Schwelgern coke-oven plant
                         at ThyssenKrupp Stahl AG in Duisburg/Ger-
                         many commenced in the early 1990s.

                         During the more than 100-year history
                         of the August Thyssen coke-oven plant,
                         housing developments in the Bruckhausen
                         district of Duisburg grew ever nearer to
                         the perimeter of the works site. Over time,
                         residents' complaints about emissions from
                         the works and demands for the coke-oven
                         plant's closure became more and more

                         As the old coke-oven plant in Bruckhausen
                         could no longer be revamped to comply
                         with modern-day ecological requirements,
                         plans took shape to replace it with a new
                         facility. Ideally, the new plant should be
                         located outside the densely populated
                         residential areas but still close enough to
                         the steelworks in order to ensure delivery
                         of the 2.5 million tons of coke per annum
                         required by the two large blast-furnaces in
                         Duisburg-Schwelgern and to maintain the
                         gas network between the steelworks' ovens
                         and the power station. A suitable site for

the new coke-oven plant was found on the       world's most modern, environmentally-
peninsula between the Schwelgern harbour       friendly and, in terms of its dimensions,      The main milestones
and the River Rhine.                           unique coke-oven plant took shape on the
                                                                                              09.11.1998   First notice of approval for the
                                               basis of engineering performed by Uhde.                     construction of the Schwelgern
Uhde engineers were involved in the design                                                                 coke-oven plant
of the Schwelgern coke-oven plant from the     Commissionin of the plant started on
                                                                                              30.03.2000   Official groundbreaking
start. Beginning in 1996, they drew up the     December 20th 2002 by heating battery 2
                                                                                              06.07.2000   Laying of the foundation stone
technical concepts on the basis of their own   under the watchful eyes of our experienced
modern technologies for coke ovens and gas     technical crew. As each individual function    28.05.2001   Start of refractory construction

treatment plants, and compiled the neces-      module and plant section came on stream        01.10.2001   Start of mechanical assembly
sary license application documents and the     it justified the technical concepts selected   20.12.2002   Heating start-up
safety analysis.                               for the plant and confirmed the successful     13.03.2003   First coke
                                               handling of the project by the parties con-
In November 1998 the license for the pro-      cerned, whose team spirit was exceptional.
ject was granted, and the detail engineering   The first coke was pushed on battery 2 on
commenced immediately afterwards. When         March 13th 2003, some 6 weeks earlier than
the engineering phase was in full swing        planned, and on battery 1 on May 21st 2003,
there were as many as 200 engineers at         3 months ahead of schedule.
Uhde alone engaged in implementing the
design concepts. More than 12,000 engi-        Using the most modern environmentally-
neering documents were produced with the       friendly technologies and the highest pos-
aid of state-of-the-art equipment during the   sible level of automation, the Schwelgern
3-year engineering phase.                      coke-oven plant achieves a production ca-
                                               pacity of 2.64 million tons of coke per an-
Within three years of the official ground-     num and 155,000 m3 coke-oven gas per
breaking in March 2000 and the laying          hour, setting new standards world-wide.
of the foundation stone in July 2000, the

The Coke-Oven Batteries

                          The challenge

                          The challenge facing the plant design engi-
                          neers was to rate the coke-oven batteries for
                          a coal throughput of 10,600 t/d - equivalent
                          to a coke output of around 2.6 million t/a
                          - while minimising the operating personnel
                          requirements. At the same time, consid-
                          eration had to be given to the restrictions
                          imposed by the very limited building space,
                          plus a tight budget and demands for the
                          best possible protection of the environment.

                          The engineering

                          The challenge was accepted and the
                          demands were met in full using concepts
                          developed through experience and exper-
                          tise accumulated in a host of international

                    COKe SIDe                                                                 PUSHeR SIDe
                                                 COAL CHARGING CAR

                 COKe TRANSFeR CAR


                      QUeNCH CAR                                                   PUSHeR MACHINe

                                                                                                            BATTeRy CROSS-SeCTION


The results

We are proud that our engineering work             The well-proven CONTROLPRESS® bracing
has resulted in a major contribution to the        system guarantees the required pre-stress-
successful construction of a coking plant          ing and gas-tightness of the refractory walls
with the world's largest coke oven batter-         of the very tall ovens under all operating
ies. The following features are particularly       conditions.
                                                   The batteries were heated up using spe-
The large dimensions of the oven chambers          cially designed blower burners which can
allow the specified coal throughput to be          be operated over a wide control range and
achieved by only two batteries of 70 ovens         which ensure uniform, controlled heating of
each, for which relatively little space is re-     each battery refractory block.
quired. The necessary charging and coke-
pushing operations are performed with only         Careful selection of suitable materials and
one set of oven servicing machines.                equipment allowed the project to stay within
                                                   the budget without detracting from the qual-
                                                   ity standards required for the safe operation
                                                   of the plant.

Innovative environmental Protection at the Battery

Heating system                                   Single-chamber pressure control

The heating system for low-NOx combus-           The innovative PROven® system for single-      As coking proceeds, the chamber pres-
tion, which was specially designed for these     chamber pressure control allows the pres-      sure is gradually increased in step with the
large ovens, is equipped with a 3-stage air      sure in each individual oven chamber to        reduction in the gas generation rate inside
supply system. About half the combustion         be adjusted as a function of the actual raw    the oven. When the gas output approaches
air enters the bottom of the heating zone        gas generation rate, providing the opti-       the end of the coking process, the pressure
through the air duct, while the other half       mum pressure level for the given coking        in the oven is raised to the point where no
enters the heating zone through two air          condition. The gas collecting main itself is   air can be drawn in at the doors. This pro-
ports positioned at different levels in the      operated under suction, and the pneumati-      tects the refractory walls from combustion
binder wall. The regenerator chambers are        cally actuated PROven® valve controls the      in the end zone of the chambers, thus pro-
divided longitudinally in order to permit        back-pressure in the chamber. The control      longing the service life of the ovens.
individual control of the bottom air and wall    system is based on the adjustment of
air flows. This results in an optimum vertical   the water level inside the PROven® valve,      Charging-gas aspiration
temperature distribution over the heating        providing a variation of the valve port area
walls while reducing the NOX content of the      through which the raw gas flows.               The PROven® system also ensures that the
exhaust gas to a very low level.                                                                charging gases are retained within the raw
                                                 A low chamber pressure is set at the begin-    gas system because the standpipes and,
                                                 ning of the coking time so that the large      consequently, the oven chambers are under
                                                 raw gas quantities generated in this phase     suction when charging takes place. Coke
                                                 are discharged without highgas pressures on    oven doors with an efficient sealing system
                                                 the oven doors. Door and oven top emis-        and water-sealed standpipe lids are further
                                                 sions are thus prevented almost entirely.      safety measures for preventing battery


                          Pressure measurement line                Pneumatic
                                                                               Control valve


                       Oven roof                                                      Fix Cup-valve: ∆H~∆P

                       Gas collecting space


PROven® arrangement

     Coke Stabilisation Quenching / CSQ

     CSQ - Quenching Tower                                   The challenge

                                                             Initially it was planned to equip the
                                                             Schwelgern coke-oven plant with a dry
                                                             coke-cooling system in order to meet the
                                                             environmental protection requirements
                             Fresh water
                                                             and to recover the energy of the hot coke.
                                                             However, in view of the fact that energy
                                            Conventional     demands at the Duisburg steelworks site
                                           Quenching Tower   were already largely covered and with a
                                                             low return on investment from the recov-
                                                             ered energy, it was decided to develop an
                                                             optimized wet quenching system which
                                                             would satisfy the environmental protection

                                                             The engineering

                                                             The engineering-concept was based on the
                                                             wet quenching system that had been used
                                                             successfully for a number of years at the
                                                             coke-oven plant of the Krupp Mannesmann
                                                             steelworks. This system has environmental-
                                                             ly-friendly features that are comparable with
                                                             dry cooling, is highly reliable and stabilises
                                                             the coke during the quenching operation.

CSQ quenching car

The results

Thus the CSQ wet quenching system was          The CSQ quenching tower is approximately
developed, which is accepted as being          70 m tall and has two levels of specially
equivalent to a dry coke-cooling system        configured fin-shaped baffle separators for
even in terms of Germany's very strict         the removal of dust. The ascending vapours
environmental protection regulations. This     are also scrubbed with water and partly
system consists of the following functional    condensed. Particulate emissions are thus
units:                                         largely prevented and are lower than with a
                                               dry cooling system.
The major portion of the quenching water
is fed into the hot coke bed from below        Recycled quenching water is cleaned in
in the CSQ quenching car. The mixture          the quenching water settling tank. The coke
of steam and water that develops in the        breeze sediment is recycled as sintering
area of contact quickly cools the coke and     coke.
propels it upwards. When the coke drops
again, the fine particles are separated from   The CSQ system, which was implemented
the coarse grain and the coke is stabilised.   for the first time in its complete form at the
The formation of gaseous emissions is          Schwelgern coke-oven plant, represents an
greatly reduced by the high cooling rate. In   efficient wet quenching process that pro-
fact, these emissions are lower in the CSQ     vides a high level of environmental perfor-
process than in a dry cooling system.          mance for a relatively low investment.

Gas Treatment

                                                                                                                   Gas Flare

 Crude COG
                                 Primary                            Gas-          H2S/NH3-               BTX-
                                 Cooling                          Exhauster       Scrubbing            Scrubbing
                                                                                                                    Clean COG

     Flushing Liquor                                                                                    BTX-
                       Tar & Liquor                                                                                Crude Benzene
      Solids                               Crude Tar

                       Coal Water                                                 Desorption
                                                                                                Waste Water


The challenge                                    The engineering

A state-of-the-art gas treatment plant was       The plant, which was designed by our en-
to be installed at the Schwelgern site. The      gineers in close cooperation with experts of
plant had to satisfy the environmental pro-      the ThyssenKrupp Stahl engineering team,
tection regulations in force for water and air   uses state-of-the-art processes and the lat-
while complying with the tight budget. The       est equipment, and represents the optimum
available building site – situated between       solution in terms of both economy and
the batteries and the bank of the River Rhine    ecology.
– required a compact arrangement of the
plant sections and short routes for the gas      To achieve the highest possible reliability,
and utilities.                                   the major items of equipment were rated
                                                 with 50 % spare capacity. The costs were
                                                 held within the specified budget in spite of
                                                 introducing extensive measures for minimis-
                                                 ing air emissions, water pollution and noise.

                                                                                                  Gas Treatment

The major processes

The gas pre-cooling system consists of six        decanted into raw tar and water. The raw        in the desorption columns are processed
horizontal-tube primary coolers, four of which    tar with a water content of less than 3% is     in a COMBICLAUS® unit to produce liquid
are in operation and two on stand-by. The raw     a saleable product and is pumped to the tar     sulphur, with the ammonia being simultane-
gas from the batteries is cooled in the prima-    tanks for intermediate storage. Solids are      ously decomposed into its constituents N2
ry coolers to approximately 24 °C. Hot water is   removed from the tar by centrifuging and        and H2. The residual gases are recycled to
withdrawn from the uppermost cooling stage        are recycled to the coking coal. The surplus    the raw gas mains, resulting in no emis-
for heating purposes. The tar content of the      ammonia liquor is fed to the H2S / NH3 strip-   sions whatsoever. To fully satisfy environ-
gas is reduced to less than 10 g/m3 (STP) by      ping system for further treatment.              mental protection requirements, a stand-by
three electrostatic precipitators, two of which                                                   COMBICLAUS® unit is provided.
are in operation and one on stand-by. The gas     The gas compressed in the exhausters is
is then compressed in the gas exhausters          cleaned in the gas scrubbers to the degree      The final scrubbing stage is the BTX scrubber
to a pressure of 175 mbar. One exhauster          necessary for its subsequent use. The gas       where the benzene, toluene and xylene are
is steam-driven, the second is driven by an       desulphurising system is based on the           removed from the gas to a residual content of
electric motor and the third is a standby         CYCLASULF® process.                             less than 8 g/m3 (STP). At the same time, the
unit provided with both types of drive.                                                           naphthalene content is reduced to below
                                                  In this process, which was developed by         0.1 g/m3 (STP). After treatment in these puri-
In the tar and liquor system the condensate       Uhde engineers, the H2S content is reduced      fication steps, the coke-oven gas is a valuable
separated from the gas stream before it           to < 0.5 g/m3 (STP) and the NH3 content to      and environmentally friendly fuel which is
enters the pre-coolers is processed and           < 0.02 g/m3 (STP). The vapours stripped         exported into the steelworks gas network.


                                                                                                 GasControlTM     BatControlTM   CoalControlTM

                                                                                                  SimuGasTM      PushSchedTM     CokeControlTM





The challenge                                   The results

To be able to operate the Schwelgern coke-      To meet the challenge, the following system             The ManuThermTM system is an infrared
oven plant at optimum efficiency, it was to     structure was evolved under the umbrella                pyrometer with integral data memory for
be equipped with the latest state-of-the-art    of the COKEMASTER® automation architec-                 taking manual measurements at the heat-
automation technology. The aim of automat-      ture:                                                   ing flues. Its main job is to measure heating
ing the process sequences was to facilitate                                                             flue temperatures when no AutothermTM
long-term modifications required to meet        The AutoThermTM measuring system uses                   measurements are available, for instance
environmental protection requirements.          its six infrared sensor heads to measure                when no coke-pushing is taking place
                                                the surface temperatures of the two heat-               for operational reasons. Also, detailed
The engineering                                 ing walls at three different levels during              spot measurements can be taken where
                                                each coke-pushing operation. In other                   heating problems have been detected by
Uhde has been successfully engaged in the       words, the heating walls are thermally                  AutoThermTM. These temperature measure-
automation of coke-oven plants since 1980.      scanned enabling an exact overview to be                ments are fed into the computer system
The automation systems are always tailored      obtained of the temperature distribution                and can be used for further calculations
to the customer's specific requirements,        in each heating wall. The aim is to keep                and evaluations.
and the Schwelgern coke-oven plant is no        the temperature distribution in the heating
exception. The modular design of the auto-      walls as uniform as possible and to detect              The BatControlTM system calculates the
mation systems favours this approach.           any changes.                                            amount of heat required for the battery,

 Automation system
for battery operation
                                                                 Level 2 process computer/battery

                          ManuThermTM            PushSchedTM                  AutoThermTM                       RamForceTM                       BatControlTM
                           Heating flue          Scheduling of                  Oven wall                         Pushing                        Heat quantity
                          temperatures          oven machines                 temperatures                         forces                          control

                                                            Scheduling of
                           station                                                    Coordination PCL for oven machines                                DCS
                                                           oven machines
                        control room

                                                                                                                                                   Heat quantity
                                            Coal                                                         Coke                   Coal                 control
                                          charging                   Pusher machine                    transfer                quench
                                            car                                                           car                    car

                         Heating flue                         Oven wall           Pushing                                                             Process
                        temperatures                        temperatures           forces                                                               data

taking into account all relevant operat-              the machines. Confirmations received from            sheet. The model is supplied with the nec-
ing parameters such as coal quality, coal             the oven machines are forwarded to the               essary online process variables of the plant
moisture, coke-pushing schedule, etc. The             BatControlTM system in order to make auto-           instrumentation in real time mode (via the
heating situation is automatically controlled         matic corrections to the heating.                    process control system) and the process is
and the heat input is immediately corrected                                                                calculated dynamically. By varying the con-
upon detecting a fault, such as a delay in            The GasControlTM system is a process                 trol parameters (e.g. steam rate, water rate,
production or a change of temperature.                model for gas treatment plants. The pro-             etc.) in this virtual plant it is possible to
                                                      cess model consists of the commercial                optimise the operating results. The control
The PushSchedTM system is an automatic                simulator CHeMCAD for chemical plants                parameters that deliver the best operating
pushing and charging schedule calcula-                plus extension modules developed by Uhde             results are re-transmited to the plant in-
tion program designed to assist operating             for individual coke-oven-specific machinery          strumentation in order to set the local con-
crews. The production plan is re-calculated           and equipment. The GasControlTM process              trollers in the "real" plant. All important data
continuously after every coke-pushing                 model uses chemical and thermodynamic                can "be displayed on screens, reports and
operation considering special operational             mass equilibria and streams to rate each             trend charts.This model is not only a power-
situations such as "oven with extended cok-           individual gas treatment unit, determines            ful tool for plant optimisation and automa-
ing time" or "oven shut down". The result-            the input and output streams, and interlinks         tion – it can also be used in an off-line simu-
ing production schedule is transmitted to             them in accordance with the plant flow-              lation mode as a training tool for operators.

                                                                                                                                         Automation system
                                       Level 2 process computer/gas treatment                                                            for gas treatment
                                                            exchange of data                                                             plant operation
               Gas TreatmentTM
              Process optimization
                                                               SimuGasTM                                      data base
                                                            Process simulator
                                                                                  Copying of actual data

                  Operator           Set simulation                                                           Laboratory
                   station                                                DCS
                                       scenario                                                                  data
                control room



                                                                   CP 300/1500e 01/2012 ThyssenKrupp Uhde/ TK printmedia/Printed in Germany

    ThyssenKrupp Uhde
    Friedrich-Uhde-Strasse 15
    44141 Dortmund, Germany
    Tel.: +49 231 5 47-0 · Fax: +49 231 5 47-30 32 ·

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