Maamba Collieries Combating Pollution Through Technology Upgrades

The technology upgrades at Maamba Collieries have enhanced pollution control at the thermal plant. It has been five years since the commissioning of the plant.

Maamba Collieries is involved in coal mining and power generation. It stands as Zambia’s largest independent power producer. Its US$900 million thermal plant generates 300 megawatts of power. The mine’s coal concentration covers 7000 hectares.

The mine produces both low grade and high grade coal. The high grade coal that is produced is sold to local manufacturers and breweries whilst the low grade coal (60%-65% of what is mined) is sent to the power plant.

CFPP (Coal Fired Power Plant)

This modern day thermal plant is built in close proximity with the mine. It uses some latest technology facilities to burn coal and convert it into electricity.

• The plant has 2×510 TPH Steam Generators with circulating fluidized bed combustion technology.
• A 48Km, 330 kilovolts double transmission line
• Roll water Pumphouse
• 21Km Pipe from Lake Kariba
• Coal Stacker Cum Reclaimer which recovers the bulk coal from the stockpile.  
• Generator transformer which is a transformer connected to the generator directly in order to step-up the voltage.  
• Switch yard which is the interconnection between generation and transmission.

Pollution Control Using ESP Technology

Low grade coal has a high Sulphur content and produces a lot of ash when it is burned. This causes air pollution. The ESP (Electro-Static Precipitator) is a pollution control device that traps these impurities. It does this by ionizing dust particles using a high voltage electric field and charging dust particles. The principle is that when the smoke dust passes through electrodes, the first electrodes are charged to a very high negative voltage. Through this they gain a negative charge. As they continue moving through the pipes they meet second electrodes that have a high positive voltage. Opposite charges attract so the negatively charged particles get attached to the charged plates.

Maamba power plant burns 5000 tonnes of coal every day and the ESP is able to trap 2500 tonnes of ash every day. There is need to insure that the Sulphur Oxide emission is at a very minimal value which follows the set standard by regulatory boards who are Zambia Environmental Management Agency and The World Bank.

Load Shedding

The thermal plant has helped diversify the energy sector by reducing hydropower dependency. It contributes 10% of power generation in Zambia. This contribution has helped reduce load shedding by 4 hours.