Dung Quat refinery Project Profile (Part 5 of 7)

* Crude Distillation Unit (Unit 011)
- Capacity Design: 6.5 Million tonnes per annum (148.000BPSD in case sweet crude and
141.000 BPSD in case sour crude).
- General Description
Crude enters the Crude Distillation Unit (CDU) and is preheated against product and pumparound streams prior to entering a fired heater. The crude is split into a number of products in a main fractionator and associated side stream strippers. Overhead Naphtha is further processed in a stabiliser and a splitter.

The CDU products are:
Product Destination
Whole Range Naphtha Naphtha Hydrotreater
Kerosene Kerosene Treater Unit
Light Gas Oil Tankage (via Blending)
Heavy Gas Oil Refinery Tankage
Atmospheric Residue RFCC

- Light ends from the CDU are sent via the RFCC gas plant to the LPG Treater Unit (LTU). -Naphtha is fed to Naphtha Hydrotreater Unit (NHT) and following to Naphtha Spliter where Naphtha is split in to Light Naphtha and Heavy Naphtha.
+ Light Naphtha from the Naphtha Spliter is routed to Isomer Unit.
+ Heavy Naphtha from the Naphtha Spliter is fed to the Continuous Catalytic Reformer Unit (CCR).

-Kerosene from the CDU is routed directly to Kerosene tankage or it is used as a blend stock for diesel and fuel oil production, or it is sent to the Kerosene Treater Unit (KTU). In the KTU the levels of mercaptan, hydrogen sulphide and naphthenic acids are reduced, and water is removed. The treated kerosene is then sent to tankage where it is used for Jet A1 grade kerosene.
-Light gas oil from the CDU is pumped directly to the Diesel blenders and from there to tankage at the Product Tank Farm.
-Heavy gas oil is pumped to tankage at the Refinery, from which it is pumped to the Diesel/Fuel Oil blenders.
- Residue from the CDU flows to RFCC where it is upgraded into higher value intermediate products.

* Naphtha Hydrotreater (Unit 012)
- Capacity: 23.500BPSD
- Licensor: UOP ( Universal Oil Product).
- General Description
The Naphtha Hydrotreater Unit is required to process the whole range naphtha stream from the Crude Distillation Unit (CDU).

A single fixed bed catalyst reactor is employed and the catalyst regeneration cycle life is a minimum of 2 years. Facilities shall be provided to regenerate catalyst in-situ.

Naphtha product from the Naphtha Hydrotreater Unit is routed directly to the Naphtha Spliter. Off-gas from the NHT shall be routed to the RFCC Gas Plant for processing through the fuel gas amine absorber.


* Continuous Catalytic Reformer (Unit 013)
- Capacity: 21.100 BPSD
- Licensor: UOP ( Universal Oil Product)
- General Description
The Continuous Catalytic Reformer processes hydrotreated straight run heavy naphtha feedstock from the Naphtha Spliter.
The reactor feed contacts with a recirculating catalyst, which is continuously regenerated to maintain activity.
Reactor effluent is separated into a hydrocarbon liquid stream and a hydrogen rich gas stream. Valuable hydrocarbon liquids are recovered from the hydrogen rich gas stream.
The Reformate liquid stream undergoes re-contacting and fractionation to produce Reformate and un-stabilised LPG.
The Reformate is routed directly to tankage at the Refinery. The un-stabilised LPG is blended with other refinery LPG streams before being routed to storage at the Product Tank Farm.


* Kerosene Treater (Unit 014)
- Capacity:10.000BPSD
- Licensor: Merichem.
- Technology: Filber – film Contact.
- General Description
The Kerosene Treater Unit is designed to process the Kerosene cut from the Crude Distillation Unit.
The Kerosene Treatment Unit is designed to reduce mercaptan levels, hydrogen sulphide and naphthenic acids, from the straight run kerosene feedstock produced in the CDU.
Fresh caustic for the unit is provided at the desired concentration from off plot facilities.
The Kerosene Treatment Unit removes all water from the product. The required product specification is achieved in one stage of extraction.
Product from the Kerosene Treater is routed to tankage, from tankage it is either sold as Jet A1 grade kerosene or used as a blend stock for Diesel and Fuel Oil. The Kerosene Treater produces kerosene capable of meeting the Jet A1 specification.
A weak amine solution (MEA) will be used on the KTU on an infrequent batch basis for regeneration of the catalyst.


* Residue Fluid Catalytic Cracking (Unit 015)
- Capacity: 69.700BPSD
- Licensor: IFP
- Operation Mode: - Maximise RFCC Naphthan ( Maximise Gasoline)
- Maximise LCO ( Maximise Distillates )
- General Description

Convertor Section
The Unit receives hot atmospheric residue directly from the Crude Distillation Unit (CDU), or cold from tankage.
The Convertor Section of the RFCC shall produce the following streams:
- A wet gas stream which is routed to the RFCC Gas Plant
- An overhead distillate which is routed to the RFCC Gas Plant
- A light cycle oil (LCO) which is routed to tankage and then to LCO-HDT.
- A decant oil (DCO) which is routed to fuel oil blending or to refinery fuel oil.
The Converter Section comprises the reactor/regenerator section, main fractionator, waste heat boiler, catalyst handling, LCO stripper, product cooling/rundown equipment and associated facilities.

RFCC Gas Plant
The wet gas and overhead distillate from the main fractionator are charged to the RFCC Gas Plant, which shall produce the following streams:
- An unsaturated off-gas from the amine absorber located within the RFCC Gas Plant.
- A mixed C3/C4 stream which is routed to the LPG Treater Unit prior to separation within the Propylene Recovery Unit.
- A whole naphtha stream which is routed to the RFCC Naphtha Treater Unit;
- The RFCC Gas Plant includes two amine absorption columns to treat fuel gas and LPG prior to them leaving the Unit and will use a stream of lean amine from the Amine Regeneration Unit (ARU). The rich amine stream shall be returned to the ARU from the RFCC Gas Plant.


* LPG Treater (Unit 016)
- Capacity: 21.100 BPSD
- Licensor: Merichem
- Technology: Fiber – film Contact
- Process: Thiolex Technology Two stage
- General Description
The LPG Treater Unit (LTU) is designed to process the C3/C4 stream from the RFCC Gas Plant prior to routing to the Propylene Recovery Unit. The bulk of the H2S in the LPG stream is removed in an amine absorber, located in the RFCC Gas Plant.
The LTU is designed to reduce mercaptan and H2S levels in the C3/C4 product, when charged with design feedstock.

* RFCC Naphtha Treater (Unit 017)
- Capacity: 45.000 BPSD
- Licensor: Merichem
- Process: Mericat II
- Technology: Fiber – film contact
- General Description
The Naphtha Treater Unit (NTU) is designed to process the RFCC Naphtha from the RFCC. The unit is designed to produce a sweet (i.e. low mercaptan sulphur) naphtha product. Product from the NTU is routed to the Mogas blenders.
Off-specification storage is provided downstream of the NTU.
Fresh caustic at the desired concentrations is supplied to the unit for use in the treaters. Spent caustic from the treaters is routed to the Spent Caustic Neutralisation Unit.


* Sour Water Striper (Unit 018)
General Description:
Sour water from the CDU, NHT and RFCC units is fed to a surge drum where hydrocarbons are degassed. These sour gases are routed to the sour flare header.
Combined sour water is pumped via feed / bottoms heat exchanger to a single stripping column where dissolved ammonia and hydrogen sulphide are removed from the sour water.
Sour gas overheads from the stripper column are condensed and refluxed, and the residual concentrated sour gas is directed to the sour flare header.
Stripped water is cooled against incoming feed and air prior to routing to the effluent treatment plant. A slipstream of stripped water is used as desalter water on the CDU.
A sour water storage tank is provided to allow for outages on the unit. The tank is sized to give two days storage of sour water. Under normal operation the tank will be by passed and so will be normally empty.


* Amine Regeneration Unit (Unit 019)
General Description:
Combined rich amine from the RFCC unit is routed to a feed surge drum where hydrocarbons are skimmed and degassed from the amine. Skimmed oil is routed to light slops and sour gases are scrubbed and routed to fuel gas.
Rich amine is routed via feed / bottoms heat exchange to a regeneration column where hydrogen sulphide is stripped.
Sour gas overheads from the column are condensed and refluxed, and the residual concentrated sour gas is directed to the sour flare header.
Stripped lean amine is cooled against incoming feed and air. The lean amine is then pumped and treated with anti-foam agent (if required) back to the H2S absorbers on the RFCC. A slipstream of amine is filtered to remove impurities.
An amine surge tank is available to hold the total refinery amine inventory in the event of a shutdown. Fresh amine is stored in a small make-up tank for preparation of initial and make-up solutions.

* Spent Caustic Neutralisation Unit (Unit 020)
General Description:
The Spent Caustic Neutralisation Unit is required to neutralise and remove phenolic and naphthenic oils from various spent caustic streams.
The spent caustic is degassed and then neutralised by treating with sulphuric acid. The neutralised brine is routed to the effluent treatment plant. The Sour Gas produced from the unit is routed to Sour Flare Flows to the unit are on both a batch and continuous basis.
The unit is designed to produce neutralised brine with a pH of between 6-8, when charged with design feedstock.
Fresh sulphuric acid is supplied to a storage tank within the battery limits of the unit.


* Propylene Recovery Unit (Unit 021)
General Description:
The PRU is designed to process the mixed C3/C4 stream from the LPG treatment unit. The PRU will separate and purify propylene to polymer grade (99.6wt%) specification.
The first stage in the process is a C3/C4 splitter, which removes C4’s from the LPG.
The main propane/propylene splitting facility normally has two stages. The first of these is a de¬ethanising stage, which releases products lighter than Propylene. The second stage is the Propane/Propylene splitting column, which is a low-pressure heat pumped column.
The propylene product from the propane/propylene splitter undergoes further purification. The first stage would be secondary carbonyl sulphide removal over a dry catalyst bed. The second purification stage normally consists of removal of arsenic, phosphorous and antimony, again over a dry catalyst bed. The purification stages are combined in a single vessel.

* Sulphur Recovery Unit (Unit 22)
A Claus Sulphur Recovery Unit (SRU) shall be provided in Package Unit type. The Unit shall have capacity of processing 3 tons/day of sulphur to process acid gas from ARU, ammonia acid gas from SWS and off-gas from CNU.
Acid Gas from ARU sent to Thermal Reactor, Ammonia Acid Gas from SWS and Off-gas from CNU sent to Incinerator.
Free Sulphur in the Sulphur Product will be 99.9% minimum, and Sulphur Recovery of the Claus Unit does not less than 92.6%.
Emissions of NOx, SOx, and CO concentrations from SRU Incinerator will meet Vietnamese Air Quality Standard TVCN 5939-1995.


* Izomerization Unit (Unit 23)
- Capacity: 6.5000 BPSD
- Licensor: UOP (Universal Oil Product)
- General Description
ISOMER will be added to produce Isomerate product by using hydrotreated light naphtha as feedstock in order to improve octan number of gasoline pool.


* LCO Hydrotreating Unit (Unit 24)
- Capacity: 1.320.000 tonnes per annum
- Licensor: IFP (Axens)
- Description:
LCO-HDT will be added to treat the LCO produced in RFCC Unit in order to make it possible to be blended into Auto diesel pool, by hydro-treating the LCO to improve the stability.