Particle Size Applications for Power Plants

The importance of particle size for power plants is found in their ability to meet environmental regulations while controlling capital expenditures and operating costs. The size of materials such as limestone, lime, and trona impacts the efficiency of desulfurization processes. By-products such as gypsum and fly ash may be sold to various applications depending on their size as well. This application page will show how investing in particle size analysis helps control operating costs and improve margins for power plants.

Emission Control Methods Related to Particle Size

Many technologies exist to remove SO_x, NO_x, and other components from the flue gas produced by power plants. Some of those technologies utilize materials to react with the flue gas to cleanse it of pollutants. The particle size distribution of those materials directly impacts the efficiency of the emission control method. A short description of the particle size-related technologies follows.

Flue Gas Desulfurization

As the name implies, flue gas desulfurization methods aim to remove SO₂ from the process stream. The "wet" version of the method typically involves limestone and water to force oxidation. Gypsum is produced as a by-product and may be re-used or sold after dewatering. The dry, or semi-dry, version of the method often features a lime slurry which is atomized and injected into the flue gas. SO₂ removal efficiencies for the two versions are similar for low-sulfur fuels.

For flue gases producing too much SO₃, dry sorbent injection may be used to meet emission targets. Common sorbents include trona (sodium sesquicarbonate) and baking soda (sodium bicarbonate). Both materials will calcine above a certain temperature and remove SO₃ and SO₂ (somewhat less efficiently), creating a sodium sulfate salt as a by-product. The calcination process critically determines the dry sorbent efficiency as the evolution of water and carbon dioxide creates a more porous structure, thus increasing the number of reaction sites, thus improving the SO_x removal efficiency.

Particle Size Analysis of Power Plant Applications

The LA-960 Laser Particle Size Analyzer quickly and easily measures dry powders such as trona or wet materials such as a lime slurry. Any sample with particle size between 10 nanometers and 5 millimeters may be measured in less than 60 seconds with the LA-960. Dry powders are measured using the PowderJet accessory.

Particle size overlay of multiple fly ash measurements using the LA-960 PowderJet

Comparison of fine and coarse samples of trona as measured by the LA-960 PowderJet

Overlay of fly ash and Portland cement as measured by the HORIBA LA-960

Particle size distribution of gypsum produced in flue gas desulfurization

Summary of Benefits

The LA-960 Laser Particle Size Analyzer easily measures materials either consumed or produced by power plants. Capable of measuring powders, slurries, and suspensions between ten nanometers and five millimeters with only a single mouse click, the LA-series has the performance and ease of use required by users in this environment. The LA-350 represents a portable, liquid-only sizing option for users with slightly different needs.