Monday, 28 January 2013

Oil refinery

An oil refinery or petroleum refinery is an industrial process plant where crude oil is processed and refined into more useful products such as petroleum naphtha, gasoline, diesel fuel, asphalt base, heating oil, kerosene, and liquefied petroleum gas.

Crude oil is separated into fractions by fractional distillation. The fractions at the top of the distillation column have lower boiling points than the fractions at the bottom. The heavy bottom fractions are often cracked into lighter, more useful products. 

Gas (also known as liquified petroleum gas (LPG))

Gasoline (also known as petrol)
Kerosene (also known as jet aircraft fuels)
Lubricating oil
Heavy gas oil
Residual (examples are asphalt and tar)

Friday, 25 January 2013

Single export countries

Some countries depend on one product for more than 50% of their exports.

Why is it dangerous for a country to be too dependent on just one export product?

Thursday, 10 January 2013

Water Treatment Process

Water in lakes and rivers often contains impurities. The water can also contain bacteria and other microbiological organisms that can cause sickness and disease. So water from most surface water must be cleaned before is can be consumed. That's the work of a wastewater treatment plant.

How does the dirty water you flush down a toilet get cleaned safely before it's released to the environment? How water is treated and delivered to your home as water that is safe to drink. Follow a drop of water from the source through the treatment process.

Different steps in the Water Treatment Process:


Coagulation removes dirt and other particles suspended in water. Alum and other chemicals are added to water to form tiny sticky particles called "floc" which attract the dirt particles. The combined weight of the dirt and the alum (floc) become heavy enough to sink to the bottom during sedimentation.

The heavy particles (floc) settle to the bottom and the clear water moves to filtration.

The water passes through filters, some made of layers of sand, gravel, and charcoal that help remove even smaller particles.

A small amount of chlorine is added or some other disinfection method is used to kill any bacteria or microorganisims that may be in the water.

Water is placed in a closed tank or reservoir in order for disinfection to take place. The water then flows through pipes to homes and businesses in the community.