Creating Energy-Efficient Plants

Creating Energy-Efficient Plants

Leading by Example

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Energy Efficient Plants Energy Efficient Plants

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Thermal efficiency is defined as the ability to convert a fuel into useful work. A typical "coal-fired" power plant has a 30% efficiency in converting the stored thermal energy in coal into useful work — in this case electrical power. In fact, the most efficient combined cycle power plants in the world are now able to achieve just over 60% thermal efficiency. The remaining energy is lost to the atmosphere.

At Mosaic's Bartow, Florida, plant, energy conservation and efficient generation has taken on a whole new meaning. Here, three sulfuric acid plants generate tremendous amounts of energy from the combustion, conversion and absorption of sulfur and related oxides. The total amount of thermal energy generated in one of Mosaic's sulfuric acid plants is 4.9 GJ (gigajoule) per ton of sulfuric acid produced.

Mosaic converts this energy into steam and hot water to produce new energy used to run our processing operations — all without CO2 emissions.

Here's how it works: The steam is fed into turbines to power large rotating equipment or to generate electricity, or it's used in Mosaic's plants as a high-temperature heat source, such as in our phosphoric acid evaporators or air pre-heaters in our granulation plants. Much of the hot water generated is eventually turned into steam, or is used to evaporate water from Mosaic's process ponds. What little low-value energy that remains is cooled in a conventional cooling tower or lost to the atmosphere as hot air. By integrating Mosaic's sulfuric acid plants with the rest of our facilities, Mosaic's Bartow plant can achieve thermal efficiencies of up to 75%.

In addition to creating energy-efficient facilities, Mosaic is able to produce virtually all of the energy it needs to run our fertilizer manufacturing facilities and some of what we need at our mine sites. While Mosaic's Phosphates business may never be a net-zero importer of electricity, with more than 50% of the entire electrical load of Mosaic's mining and manufacturing operations running off of sulfur-based power, we may soon get close.