Hydraulic fracturing of chemicals are used per fracturing. A typical fracture treatment uses between 3 and 12 additive chemicals. Although there may be unconventional fracturing fluids, typical chemical additives can include one or more of the following: The most common chemical used for hydraulic fracturing in the United States in 2005–2009 was methanol, while some other most widely used chemicals were isopropyl alcohol, 2-butoxyethanol, and ethylene glycol. Typical fluid types are: For slickwater fluids the use of sweeps is common. Sweeps are temporary reductions in the proppant concentration, which help ensure that the well is not overwhelmed with proppant. As the fracturing
Hydrochloric acid regeneration a combination of wet scrubbers such as venturi scrubbers (IX) and scrubber columns (X), remaining traces of HCl and dust are removed. In some plant, absorption chemicals such as NaOH and NaSO are used to bind HCl and Cl (which is created under certain circumstances in several, but not all spray roasting reactors). Pyrohydrolysis based acid regeneration processes produce a considerable amount of stack emissions containing HCl, particles and chlorine, which has led to numerous violations of the U.S. clean air act in the past. Hydrochloric acid regeneration Hydrochloric acid regeneration or HCl regeneration refers to a chemical process for