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Why Sulfine?
What does Sulfine do?
Sulfine is a new sulphuric acid production facility with steam and electricity
cogeneration. It was built to:
Each year, Prayon consumes more than 425,000 tonnes of sulphuric acid,
which it uses to produce basic phosphoric acid.
Ensure the continuity of Prayon’s Engis site
Greatly reduce the site’s ecological footprint
Before investing in Sulfine, Prayon had a unit that produced 170,000 tonnes
of sulphuric acid a year. This new facility gives Prayon additional annual capacity
of 345,000 tonnes (1,000 tonnes a day).
Thanks to this new unit, Prayon is less dependent on suppliers and the ever-changing
conditions in the market. Besides this, the company makes extremely pure sulphuric acid,
which can be used to produce top-quality phosphates.
Finally, the energy cogenerated during the production process is converted to supply
the other units on the site.
Total: 515,000 T/year
Before: 170,000 T/year
Sulfine: 345,000 T/year
What are phosphates used for?
The general public is not usually familiar with our products, which are mainly
used as raw materials for the manufacture of end products used in everyday life.
Phosphates and derived products have a wide range of applications in the food sector
(processed cheese, ham, baked goods, etc.) and in industry (from detergents and water and
metal treatment to ceramics, porcelain, plaster and much more).
NATURAL PHOSPHATES
+
SULPHURIC ACID
PLASTER
PHOSPHORIC ACID
PURIFIED PHOSPHORIC ACID
WATER TREATMENT,
METAL TREATMENT,
FERTIRRIGATION,
LITHIUM ION
BATTERIES
PHOSPHATE SALTS
FERTILISERS
WATER
DETERGENTS
METALS
SOFT DRINKS, ETC
FOOD ADDITIVES
Meat, delicatessen
products, fish,
baked goods, processed
cheese, etc
How is sulphuric
acid produced?
Diagram of sulphuric acid production
The production process for sulphuric acid
is made up of three main stages:
Stage 1: combustion Steam
Stage 2: conversion
S + O2 -> SO2 + energy
Sulphur + Oxygen
-> Sulphur dioxide + heat
Liquid sulphur is injected into the combustion
furnace. When it comes into contact with
the air, it burns spontaneously and forms
SO2, emitting a lot of heat at the same time.
The thermal energy is recovered in a highpressure boiler and converted into steam. The
steam is then passed into a turbine, where
it is used to generate electricity. Some of
the steam is used to supply the Engis site’s
steam network..
SO2 + ½ O2 -> SO3 + energy
Sulphur dioxide + oxygen
-> Sulphur trioxide + heat
Electricity
3. Absorption
SO3 + H2O -> H2SO4
The sulphur dioxide (SO2) goes into the
five-floor catalyst tower with the rest of the
oxygen and is converted into sulphur trioxide
(SO3). The heat released during this reaction
is transferred to the steam supplying the
turbine.
2. Conversion
SO2 + 1/2 O2 -> SO3
Steam
Air
Stage 3: absorption
SO3 + H2O –> H2SO4 + energy
Sulphur trioxide + water -> Sulphuric acid + heat
In the absorption tower, the sulphur trioxide reacts with water to make sulphuric acid.
The heat released during this reaction is converted into steam,
which is used directly to supply other facilities at the Engis site.
Sulphuric
acid
Sulphur
1. Combustion
S + O2 -> SO2
Acid
Why cogeneration?
Thanks to the cogeneration system, steam and electricity can be generated from
the sulphuric acid production process. Prayon makes some 1,000 tonnes of sulphuric
acid each day and so has been able to substantially reduce the amount of electricity
needed for the whole site and the amount of natural gas needed for steam production.
Steam production
The steam generated during sulphuric acid production is recovered and used as an energy source.
Sulfine generates 240,000 tonnes of steam a year, covering 35% of the Engis site’s steam needs.
This is in addition to the 35% produced by the older unit, meaning that steam production linked to
sulphuric acid totals 480,000 tonnes, or 70% of the steam needed by the site, allowing natural gas
purchases to be significantly reduced and fuel oil purchases to be stopped altogether.
Electricity generation
Sulfine’s steam turbine produces 66,000 of the 96,OOO MWh consumed by the Engis
site each year – that is, it covers 70% of the site’s electricity needs.
The new facility enables Prayon to favour steam production at some times
and electricity generation at others, depending on its needs
and the cost of each of these utilities
.
What is the
environmental impact?
Sulfine has a positive impact on CO2 emissions because most of the steam used for the site’s
activities now comes from sulphur (which does not cause CO2 emissions) instead of natural gas
and fuel oil, the latter of which the site has now stopped using altogether. This new facility has
enabled Prayon to cut total CO2 emissions for the Engis site by 43%, anticipating the efforts that will
have to be made due to the European revision of the targets set by the Kyoto Protocol.
Thanks to Sulfine, Prayon will achieve and even improve on most of its targets
for greenhouse gas (CO2) emission reduction, which were set by the Walloon Region
with the conclusion of the Chemicals Sector Branch Agreement.
Lower emissions at the Engis site:
CO2
- 43%
SO2
- 13 %
NOx
- 28 %
What is the sulphuric
acid used for?
Sources of H2SO4 (kT/year)
– before Sulfine
Old plant
Contracted
purchases
A significant share of the sulphuric acid produced is used to cover Prayon’s own needs.
After all, sulphuric acid is one of the two main raw materials required for producing basic
phosphoric acid (2.5 tonnes of sulphuric acid are needed to make 1 tonne of phosphoric acid).
Since Prayon’s sulphuric acid needs are now more than met, a greater share
of its sulphuric acid can be sold on the market. Sales have now increased from 55,000 tonnes
a year in 2006 to 190,000 tonnes.
At the same time, the logistical flow of sales and purchases has been reduced by 20%.
170
Other
purchases
145
Sulfine
165
Sources of H2SO4 (kT/year)
– after Sulfine
170
Uses of H2SO4 (kT/year)
– before Sulfine
55
Consumption
by PRAYON
425
Uses of H2SO4 (kT/year)
– after Sulfine
190
100
345
Sales
425
Where is Sulfine?
Sulfine was built next to the older sulphuric acid facility. This way, only one
control room is needed and management of the units is optimised.
A few key figures
Jobs
Around 15 direct jobs were created.
Investment budget
Prayon invested €50 million in building Sulfine.
This investment is expected to pay for itself in around 4 years.
Investment aids
Sulfine
The Walloon Region granted Prayon two different types
of investment aid for this ambitious project:
- Conventional company investment aids (linked to job creation): €1,500,000
- Energy and environmental subsidies: €1,914,200
Timing
Work began: June 2007
Plant commissioned: October 2009
Notes
Press contact
Dominique Maréchal
Rue J. Wauters 144
B-4480 Engis
Tel.: + 32 4 273 92 40
GSM : + 32 476 86 02 58
Fax : + 32 4 273 96 35
Email : [email protected]