A look at frac sand processing

• Autores: Tim Sheehan
• Localización: Industrial Minerals, ISSN 0019-8544, Nº. 549, 2013
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • The boom of shale gas in the US has been accompanied by a surge in the process called "fracking." Fracking is a more than half-century old but more recently it has become a widespread method of maximising oil and gas recovery from deep rock formations by pumping a mixture of sand, chemicals, and water into wells to increase the permeability of the formation. Injection of the fluid mixture at pressure promotes fissuring in the formation, and the frac sand, or "proppant," serves to prop open these fissures so that gas or oil can flow more freely through the formation.

    TBS operate on the principal of hindered settling of particles against an evenly-distributed upcurrent of fluidising water. Classic TBS designs utilise a downcomer to introduce feed into the upper third of the settling zone. As the particles settle, they form a fluidised bed (teeter bed) above the fluidisation water injection point. Material is then segregated based on terminal, hindered-settling velocities. Fine or light particles report to the overflow, while coarse and high-density particles report to the underflow. Particles that settle through the teeter bed are discharged through an underflow control valve.

    Paramagnetic (weakly magnetic) contaminants such as iron carbonates, or iron-coated quartz particles can be removed with more powerful wet high intensity magnetic separators (WHIMS), which use an electrically induced magnetic field to capture magnetic particles in a steel matrix. In the dry process, rare earth drum or roll magnetic separators may be utilised. Rare earth drums are 12-30 inch diameter separators up to 60 inches in length, with very high capacity and medium field strengths (approximately 6,000-8,000 Gauss).