نوع مقاله : یادداشت فنی
نویسندگان
مرکز تحقیقات آب و انرژی - دانشگاه صنعتی شریف
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
In high-rate anaerobic wastewater treatment reactors such as upflow anaerobic sludge blanket (UASB) system, gas solids
separator (GSS) plays a critical role in maintaining stability in reactor performance.Operational and performance problems of the current design include complexity and clogging of gas collection pipes due to sludge entry, excessive number of gas separators, and limitations on upflow velocities due to potential sludge washout. To overcome these problems, a new design is proposed in which the total volume of GSS is filled with gas-supernatant and flow is partially diverted to a side-basin adjacent to the main reactor. In this basin, gas is separated from supernatant, the remaining good sludge is settled and returned back to the reaction zone in the main reactor, and undesirable sludge and the associated flow is returned to the influent pump station for recycle back into the bottom of reactor. Advantages of the new design include the possibility of increasing velocity in the blanket zone without changing velocity in the clarification region. The degree of increase is dependent on the extent of flow diversion but an operational velocity of about 2.5 $mhr^{-1}$ is easily achievable even though much larger velocities are theoretically possible. Inactive sludge accumulated outside the turbulent domain of inlet openings is also made available. Horizontal velocities of at least 20 $mhr^{-1}$ underneath GSS units due to flow into the side basin is a new phenomenon in the new design which further improves gas separation. Since lesser total overlap area is needed due to larger and fewer number of settlers in the reactor (reduction factor of around 70\%), more area for fluid flow is available resulting in lower inter-GSS velocities. Furthermore, larger settlers are easier and more economical to construct and gas-collecting pipes and auxiliary appurtenances to secure GSS structures are eliminated with consequent reduced capital and operating expenses.
کلیدواژهها [English]
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