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As an extension of the fluidized bed family of separation processes, the flash reactor (FR) (or transport reactor) employs turbulent fluid introduced at high velocities to encourage chemical reactions with feeds and subsequently achieve separation through the chemical conversion of desired substances to different phases and streams. A flash reactor consists of a main reaction chamber and an outlet for separated products to enter downstream processes. FR vessels facilitate a low gas and solid retention (and hence reactant contact time) for industrial applications which give rise to a high throughput, pure product and less than ideal thermal distribution when compared to other fluidized bed reactors. Due to these properties as well as its relative simplicity FRs have the potential for use for pre-treatment and post-treatment processes where these strengths of the FR are prioritized the most. Various designs of a FR (e.g. pipeline FR, centrifugal FR, vessel FR) exist and are currently used in pilot industrial plants for further development. These designs allow for a wide range of current and future applications, including water treatment sterilization, recovery and recycling of steel mill dust, pre-treatment and roasting of metals, chemical looping combustion as well as hydrogen production from biomass. ==Properties== The vessel flash reactor is a design commonly used and is shown in the figure to the right. Gas is introduced from the bottom at an elevated temperature and high velocity, with a slight drop in velocity experienced at the central part of the vessel. Chamber A is designed to be "egg shaped", with a relatively narrow bottom cross sectional area and a wide upper cross sectional area. This configuration is designed to increase the fluid's velocity at the chamber's bottom, allowing for heavy feed particles to be in a continuous circulation that promotes a reaction site for separation processes.〔 The method of feed delivery varies depending on its phase. Solids may be delivered using a conveyor B, whilst fluids are vaporized and sprayed directly into the FR. It is then contacted with a continuously circulating hot gas that was introduced in section C. This continuously circulating gas interacts throughout the chamber with the incoming feed, with the surfaces of the particles generating insoluble salts as a result of reactions. Product mixture is then separated through E, where an exhaust vent emits gaseous products. Temperature of this stream is controlled by a coolant emitted by the vessel’s spray nozzles D.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Flash reactor」の詳細全文を読む スポンサード リンク
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