Synthesis gas (syngas) is a mixture of carbon monoxide and hydrogen. It
can be created from coal or methane reacting with steam at high
temperatures:
From coal: C + H2O → H2 + CO
Or from methane: CH4 + 1/2O2 → CO + 2H2 Lean combustion
CH4 + H2O → CO + 3H2 Steam reforming
Figure 30. Synthesis gas
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Syngas is used for production of methanol or ammonia. It is also used for
production of synthetic fuels, both diesel (Fischer–Tropsch process) and
gasoline (see Chapter 9.1.5).
7.3.1 Methanol based products
Methanol, a colorless alcohol, is a chemical used in the production of
formaldehyde, acetic acid and methyl methacrylate (MMA), and is used as a
solvent in many applications. It is also used to produce MTBE and other
products, and can be used in fuels.
Melamine resin or melamine formaldehyde (also, incorrectly, melamine) is a
hard, thermosetting plastic material made from melamine and formaldehyde
by polymerization. This plastic is often used in kitchen utensils or plates and
is the main constituent in high pressure laminates and laminate flooring.
Urea-formaldehyde is a non-transparent thermosetting resin or plastic,
made from urea and formaldehyde. It is used in adhesives, finishes, MDF
and molded objects. Its attributes include high tensile strength, heat
distortion temperature, low water absorption, mold shrinkage, high surface
hardness and elongation at break.
Phenol formaldehyde is a low-cost basic resin.
Addition of appropriate
fillers can generate high temperature-resistant grades (185 °C/370 °F).
Normal phenolics are resistant to 150 °C/300 °F. Applications include
moldings, bottle tops, resins, chemically resistant coatings for metals,
laminates, water lubricated bearings and foams for thermal insulation.
Polyoxymethylene (POM), also known as acetal resin, polytrioxane,
polyformaldehyde and paraformaldehyde, is an engineering plastic used to
make gears, bushings and other mechanical parts. It is also known in variant
trade names such as Delrin, Celcon and Hostaform. It is the most important
polyacetal resin; a thermoplastic with good physical and processing
properties.
MTBE (see Chapter 7.2.3).
Methyl methacrylate (see Chapter 7.2.2).
Dimethyl terephthalate (DMT) is an ester of terephthalic acid and methanol
and is used in the production of polyesters, including polyethylene
terephthalate and polytrimethylene terephthalate. It consists of benzene with
methyl ester groups attached. DMT has largely been replaced by pure
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terephthalic acid (PTA) as the preferred industrial route to polyester
production.
7.
3.2 Ammonia based products
Ammonia is a pungent, colorless, gaseous alkaline compound of nitrogen
and hydrogen (NH3) that is very soluble in water and can easily be
condensed to a liquid by cold and pressure. It is manufactured by the direct
combination of hydrogen and nitrogen under pressure over a catalyst. The
main process is still the Haber-Bosch synthesis invented in 1915, operating
at 15–25 MPa and between 300 and 550 °C in four reaction chambers with
catalyst. Anhydrous ammonia is mainly used for the manufacture of
nitrogenous fertilizers. It is also a building block for the synthesis of many
pharmaceuticals, for explosives, and is used in many commercial cleaning
products.
Urea CO(NH2)2 is synthesized from ammonia and carbon dioxide. It is
named for its presence in human and most land animal urine (except fish
and birds). Dissolved in water, it is neither acidic nor alkaline. Urea is widely
used in fertilizers as a convenient source of nitrogen. Urea is also an
important raw material for the chemical industry in animal feed, plastics and
resins.
Yara Porsgrunn Ammonia Fertilizer plant
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8 Utility systems
This chapter contains an overview of the various systems that provide
utilities or supports for the main process.
8.1 Process control systems
A process control system is used to monitor data and control equipment on
the plant. Very small installations may use hydraulic or pneumatic control
systems, but larger plants with up to 250,000 signals to and from the process
require a dedicated distributed control system. The purpose of this system is
to read values from a large number of sensors, run programs to monitor the
process and control valves, switches etc. to control the process. Values,
alarms, reports and other information are also presented to the operator and
command inputs accepted.
