Introduction
The chlor alkali industry is a major chemical industry that produces three primary products:
chlorine, caustic soda (sodium hydroxide), and hydrogen. These products are used in a variety of
industries, including water treatment, pulp and paper, textiles, and food processing.
In Iran, the chlor alkali industry has been growing steadily in recent years. According to some
reports, Iran's production of caustic soda has increased significantly in the past decade, with some
estimates suggesting that Iran is now the second-largest producer of caustic soda in the Middle
East after Saudi Arabia.
However, the industry has faced some challenges in recent years due to economic sanctions
imposed by the US and other countries. These sanctions have made it difficult for Iranian
companies to access the technology and equipment needed to produce and export their products.
Despite these challenges, the Iranian government has been working to promote the development
of the country's chlor alkali industry. In 2019, the Iranian government announced plans to increase
the country's production of caustic soda and other chemicals by investing in new facilities and
technologies.
The first chlor-alkali unit in Iran was established in 1963 by Abu al-Bashar Farmānfarmā in the
village of Haffar-e Sharqi, near the Karun River, close to the cities of Abadan and Khorramshahr.
The factory, initially named Petrochemical Company, was later renamed to Pasargad. The plant
used a mercury-based process and had a concrete bottom, but it is currently out of service.
Before the Islamic Revolution, the development plan for the Pasargad chlor-alkali unit was
initiated by Abu al-Bashar Farmānfarmā with a capacity of 22,000 tons of caustic per year.
However, due to the start of the Iran-Iraq War and the country's urgent need for chlorine and
caustic during the war, the unit was transferred to Shiraz by the engineer Najabat's group and
installed near the Shiraz Petrochemical Company. Later, it was handed over to the Shiraz
Petrochemical Company. The Shiraz Petrochemical Company was also shut down this year due to
environmental pollution caused by mercury.
Currently, there are seven active chlor-alkali units installed in Iran, with a nominal installed
capacity of 978,000 tons of caustic and 868,000 tons of chlorine, except for the inactive units.
However, the actual production capacity in the country is currently about 230,000 tons, and part
of Iran's caustic needs is met by imports. Therefore, Iran's share of the world's chlorine and caustic
production based on nominal installed capacity is less than one million tons annually, accounting
for 1.09% of the world's chlorine production, and Iran's actual share in the production of these
products is less than 0.337%.
Caustic plays a vital role in modern human life, and life without caustic would be challenging.
Caustic is used in the food, health, cosmetics, drinking water treatment, power plant, oil refining,
and other industries.
Iran’s chlor-alkali units:
Annual
Production
License Capacity Launch
No. Unit Name Location Holder (Tons) Date Products
Pasargad Chlorine
Unit or Liquid Chlorine, Bleaching
Khorramshahr Hafar Abad-e- Denora Powder, Hypochlorite,
1 Chlorine Nour, Iran Italy 3,750 1963 Brine, Hydrochloric Acid
Liquid Chlorine, Bleaching
Shiraz Chlorine Denora 1988- Powder, Hypochlorite,
2 Petrochemical Unit Shiraz, Iran Italy 22,000 1989 Brine, Hydrochloric Acid
Abadan Chlorine Denora Gaseous Chlorine,
3 Petrochemical Unit Abadan, Iran Italy 28,000 1993 Hydrochloric Acid, Brine
Annual
Production
License Capacity Launch
No. Unit Name Location Holder (Tons) Date Products
Bandar Imam Gaseous Chlorine,
Chlorine Denora Hydrochloric Acid, Brine,
4 Petrochemical Unit Mahshahr, Iran Italy 250,000 1994 Hypochlorite
Liquid Chlorine,
Hypochlorite, Bleaching
Isfahan Chlorine Ishterjan Powder, Ferric Chloride,
Power Plant Industrial City, Denora Hydrochloric Acid, Brine,
5 (Membrane) Iran Italy 8,000+8,000 1997 Sulphuric Acid
Liquid Chlorine,
Hypochlorite, Bleaching
Powder, Ferric Chloride,
Chlor Pars Tabriz Basmenj, Tabriz, Denora Hydrochloric Acid, Brine,
6 (Membrane) Iran Italy 16,000 1998 Sulphuric Acid
Chlorine Chemical Liquid Chlorine,
Company Denora Hydrochloric Acid, Ferric
7 (Membrane) Semnan, Iran Italy 4,000 1994 Chloride, Brine
Kimia Ben
(Khorramabad)
Chlorine Denora Liquid Chlorine, Brine,
8 Petrochemical Zanjan, Iran Italy 1,000 1994 Hypochlorite
Annual
Production
License Capacity Launch
No. Unit Name Location Holder (Tons) Date Products
Isfahan Water
Company Chlorine
9 Petrochemical Isfahan, Iran Denora 1,000 1990 Liquid Chlorine, Brine
Tehran Water Tehran, Iran
10 Company (Jeyhoun) Denora 3,000 1981 Liquid Chlorine, Brine
Liquid Chlorine,
Mashhad, Iran Hypochlorite, Bleaching
11 Ravand Mashhad (ICI, UK) ICI UK 3,000 1990 Powder, Hydrochloric Acid
Special
Economic Zone
Arvand (SEZ) in the Chlorine, Caustic Soda,
Petrochemical southwest of Hydrochloric Acid, and
12 Company Iran UHDE 660,000 2009 Sodium Hypochlorite
Arvand Petrochemical Co:
Arvand Petrochemical Co. is situated in southern of Iran. It has been constructed at site 3 of Bandar
Imam Petrochemical Special Economic Zone, on the northern coast of the Persian Gulf. Sprawling
on a 108-hectare, it seeks to help the country move towards self-sufficiency, industrial
development and to provide the related local and downstream sector with the required raw
material. Arvand was initially planned to implement olefins, MEG and EOG plants. But the olefins
plant was later transferred to Gachsaran petrochemical Co. In 2002, the petrochemical industries
Development Management Co., a subsidiary to the National Petrochemical Co. (NPC) of Iran and
a consortium of UHDE of Germany and Sazeh of Iran entered into a contract for the construction
of Chlor-alkali(CA), ethylene dichloride (EDC), vinyl chloride monomer (VCM) and polyvinyl
chloride (PVC) units. Arvand Petrochemical Co. was tasked with implementing these projects.
The APC complex consists of EDC/VCM and PVC plants as well as an air separation unit (ASU),
a CF unit, cooling towers, an air plant, a salt washing unit and brine transfer pipeline’s output
includes valuable products such as NaOH 50%, chlorine gas, Sodium hypochlorite, EDC, E-PVC
and S-PVC. After the bidding, an EP contract was awarded to the Uhde- Sazeh consortium in 2003.
CA plant:
The plant is slated to produce 660,000 ton/year of caustic soda 100% or its equivalent 1,320,000
ton/year of caustic soda 50%. the plant consists of two lines each producing half of the overall
output. Its major feedstock is brine with a density of 300-310 gr/lit. This required feed is obtained
by processing 1,196,000 t/y of washed Salt from the Sarbandar salt pond. The plant can be
classified into four major sections:
1-Brine filtration and precipitation
2-Cell room (electrolysis of sodium chloride)
3-Purification unit
4-Wastewater treatment
At the first section Na2CO3
Sodium carbonate (Na2CO3) and sodium hydroxide (NaOH) are added to the input brine. Then,
suspended solid impurities are settled and the brine is fed to the filtration unit where three different
kinds of filters namely anthracite, candle and ion-exchange filters are used respectively to remove
the suspended solid content, the dissolved solid content and the calcium and magnesium
impurities to a level of 20 ppb. (Due to the sensitivity of the membranes, the brine should have a
high purity.)
The second section
Includes 24 BM 2.7 Electrolyze. Each electrolyze consists of 168electrolyzing cells 5 of which
remain stays in stand- by mode. In electrolyzing cells, the saturated brine will be decomposed
electrically into CL- and Na+ with a current density of 5.46 KA/m2 and a current of 14.86 KA.
Some amount of hydrogen is produced in the cathode compartment of each cell. The CL- ions are
oxidized and produce chlorine gas. And the Na+ ions, after passing through the membranes,
combine with OH- ions and form NaOH or caustic soda.
The third section
Includes cooling, drying and concentration of chlor in which the chlorine gas produced by the
electrolyzes will be pumped to the drying unit. The out coming the chlorine gas will be sent to
users. At the concentration Unit, the 32% NaOH coming from the cells is concentrated to 50%.
This is then sent storage tank for sales. In the acidification unit, portions of the freed hydrogen
during hydrogen purification and the out coming chlor from the compressors are combined and
burnt in a furnace. As a result, the obtained chloridric acid will convert to HCL in a column after
absorbing water. This will be used for the plant’s consumption. The combination of chlor and
NaOH will produce sodium Hypochlorite. In the water Treatment Unit, the wastewater coming
from various units will be neutralized and diluted. It is pumped to the nearby Fajr UT complex
after its PH is regulated and its free chlorine is eliminated.
EDC/VCM Plant
The plant is designed to produce ethylene di- chloride (EDC) and vinyl chloride monomer (VCM)
as feed for the production of polyvinyl chloride (PVC). The process of PVC production consists
of two phases:
Phase one
Phase one includes production and purification of EDC which is carried out at the Direct
Chlorination, Oxy Chlorination and EDC Purification Units.
The Second phase
The second phase includes EDC Cracking, VCM Purification, Gas and Liquid Waste Incinerators
and Storage Tanks Units. The chlorine gas produced at the Chlor-alkali Unit with react with the
incoming ethylene within the reactor at the Direct Chlorination Unit yielding EDC. At the
Oxychlorination reactor, HCL reacts with oxygen and ethylene producing with the EDC produced
at the Direct Chlorination Unit will be sent to Unit 130 for purification. The purified EDC will be
pumped to the intermediary storage tanks in Unit 170, or the export storage tanks in Unit 180.
Some portion of the purified EDC will be dispatched to the Cracking Unit and will yield VCM and
HCL within the furnaces there. The HCL yielded at this unit will be sent back to the Oxy
Chlorination Plant. The VCM produced from cracking reactions within the Cracking Unit
(Unit140) will be transferred to Treatment and purification Unit (Unit150) where it will be purified
and stored at the circular storage tanks for use at the PVC Unit. In this unit, medium pressure steam
is also be produced using the heat yielded from burning waste gases.
PVC Plant
Producing PVC is one of the major goals behind setting up Arvand Petrochemical Complex. It is
designed to produce 300,000 tons per annum of S-PVC and 40,000 tons per annum of E-PVC for
local consumption. The excess produce will be exported to international markets. The plant
produces eight different grades of S-PVC powder and five different grades of E-PVC powder. The
S-PVC and E-PVC Units consist of the following sections:
VCM & Dematerialized Water Supply
Dissolving & Catalysts-Production
Polymerization
Degassing
Drying & Bagging
The VCM produced at the EDC/VCM Plant is the major feedstock of the PVC Plant. The modern
Vinnolit technology is employed for the production of PVC which has improved the quality and
the efficiency of the plant output. At the S-PVC plant, the VCM feedstock from the EDC/VCM
Unit is dehydrated and sent to polymerization section which consists of six batch reactors. They
use Intercooler technology that helps minimize production cost and improve the efficiency of this
section. In the polymerization unit of the S-PVC Plant, PVC is produced suspension method within
the polymerization reactors. Meanwhile, in addition to the VCM feed, a number of chemicals such
as catalysts, dispersants are injected in to reactors along with VCM. The out coming suspension
from reactors, enters dehydrators after passing through degassing columns. It is dehydrated by
centrifuges and is conveyed to dryers. The suspension produced in the reactors is dehydrated
within centrifuges. The product is dried by hot air from dryers. The final PVC powder product is
conveyed to bagging section. The bagged product is stored at the plant’s warehouses. In the E-
PVC Plant, much of the production process resembles that of the S-PVC Plant. The polymerization
process takes place in a continuous form. The polymerization section of the E-PVC Plant
comprises three reactors that operate continuously and yield PVC by an emulsion process. In these
reactors, VCM is converted to PVC. The produced latex is continuously injected into degassing
and then to dryers’ sections. The 50% concentrated latex is then turned into PVC by dryers using
hot air. The obtained PVC granules are put through a sieve to control the size of the granules. The
sieved granules are then conveyed to silos and eventually end up in storehouses after they are
bagged. In addition to the feedstock that is used for the production of E-PVC and S-PVC, a number
of substances are also used as additives. They include dispersant agents, catalysts, stoppers,
emulsifiers,
stabilizers, inhibitors, cross-linkings, de-foamers to name some of the most important ones. In a
broad comparison, at the S-PVC Plant the PVC cake is dehydrated by centrifuges and at the E-
PVC Plant latex is concentrated by employing the Membrane technology. At both plants, hot and
dried air is used to obtain PVC power. The dried powder obtained at both plants is later sieved and
eventually bagged and stored in warehouses.
Sulfuric Acid Concentration (SAC) Unit
The Unit is designed to recover the sulfuric acid required to be used by the CA Plant. The 78%
sulfuric acid current from the CA Plant is purified and concentrated within the stripper column
yielding 96% acid which is returned to the CA Plant after going through certain processes. The
SAC Unit has a capacity of 32 ton per day.
ASU Plant
The plant, built by Hangzhou Fortune Group of China, is designed to supply the Oxy Chlorination
with the oxygen it requires for its operation. It comprises of two identical units each with a capacity
of 7,500 normal cubic meters per hour of oxygen and 7,500 normal cubic meters per hour of
nitrogen. The two unit will be built on a piece of land covering an area of 1 hectare. The Oxy
Chlorination will require 59,400 tons of oxygen per year.
Plant Air
Arvand Complex consumes 15343 normal cubic meters per hour of industrial air. The Plat Air
Unit was built to supply this requirement. The excess volume is supplied to the neighboring
complexes. To this end, three centrifugal compressors, each with a capacity of 8000 normal cubic
meters per hour, built by Kobelco of Japan, were bought and put in operation.
Salt Washing Plant
Salt saturation pits are 22 km from the boundary of Arvand complex. It supplies the concentrated
brine that the complex requires for processing at its Chlor-alkali (CA) Plant. The process is
designed so as to either produce brine with a concentration of 300-310 g/lit from sea water or out
of the diluted brine which is returned from the CA Plant. The Chlor-alkali plant comprises three
brine concentration saturates each with a capacity of 480 cubic meters. The concentrated brine is
pumped from a distance of 22 kilometers and is stored in a tank built at Unit 020 in the CA plant.
Before it is sent to the next unit, the brine is passed through exchangers and is warmed by the
diluted brine returning from the unit. The diluted brine is then stored in another tank and is sent to
concentration pond where it is concentrated.
Compiled and written by Iman Jafari (imnjfr95@gmail.com)
