الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 33 |  |  |
| | | from | 33 | | |
Abstract
Petroleum is the major energy source all over the world. It is a complex mixture of
hydrocarbons and mainly composed of paraffins, olefins, and aromatics. Paraffin wax is high
molecular weight straight chain alkanes with 16 or more carbon atoms. Paraffin remains in
equilibrium in liquid state, but once the crude oil is pumped out from the reservoir, the
pressure and temperature are reduced; viscosity of the crude oil is increased, the paraffinic
hydrocarbons (wax) start to precipitate out of the crude oil on the pipe walls decreasing the
inner diameter of the pipeline causing difficulties in the extraction, problems in transportation
process, especially during wintertime. This is one of the most important problems in any oil
field producing paraffinic crude oils, and costing the companies millions of dollars per year.
There are approaches used for managing paraffin deposition in oil fields:
(1) Mechanical, (2) thermal, (3) chemical, and (4) microbial. The mechanical method is used
to remove paraffin deposition mechanically using devices known as scrapers or cutters.
Thermal method is used by increasing the temperature by injection of hot steam or hot oil
between tubing and casing. Chemical method can be used by injecting agents to dissolve
paraffin or changing wax crystal structure which prevents paraffin crystals from depositing
by altering their growth. The chemicals used are toxic and cause great damage to the
environment and cause long-term damage to the pipelines and wells. Therefore, microbial
degradation of paraffinic compounds has gained considerable interest for many reasons: it is
easy to handle, eco-friendly, noncombustible, non-carcinogenic, and nonpathogenic, and it
has low toxicity. Microbial degradation is also of low cost when compared to chemicals
prices. Removal of paraffin wax by microorganisms is based on their ability to degrade
viscous long chain hydrocarbons into short-chain non-viscous ones. They can also change the
structure and decrease the size of paraffin crystals which will improve the fluidity of crude
oil. Many microorganisms, such as Pseudomon as, Acinetobacter, Rhodococcus, Bacillus and
many more, can degrade alkanes/paraffins, as they use them as a source of carbon for their
nutrition and growth.