Praxair introduced its DryFrac waterless fracturing technology that can replace water use in fracturing wells through the use of liquid carbon dioxide (CO2). DryFrac’s patent-pending technology enables oil and gas producers to increase yield while reducing environmental effects associated with hydraulic fracturing, such as water sourcing and water disposal. DryFrac blends liquid CO2 with proppant, or special grades of sand, which is used to prop fractures open. The flexible and scalable technology can deliver large volumes and multiple grades of proppant into a formation. CO2 has long been recognized as a superior fluid for fracturing, particularly in water-sensitive or low-pressure formations. Compared with other waterless fracturing fluids such as propane, CO2 has the added benefit of being nonflammable. Additionally, Praxair can separate CO2 returned from the well, enabling faster natural-gas production. Much of the CO2 being used is captured from industrial effluent gas and purified. Praxair continues to develop technology to recycle and reuse CO2 for a variety of applications.