Oil and gas production handbook An introduction to oil and gas production

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 DMT has largely been replaced by pure 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 (NH
3
) 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(NH
2
)
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.