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This post was last edited by liuquan1100 on 2019-3-26 21:53. Scaling in commercial fluidized-bed reactors (including gas-phase polymerization reactors) is an important issue in production operations. Scaling has a negative impact on production efficiency, ultimately leading to shutdowns for maintenance and wasting valuable production time. Understanding the cause-and-effect relationship of scaling in reactor systems will help reduce the occurrence of this phenomenon. Scaling in fluidized bed reactors can be significantly affected by the physical processes within them, such as static electricity and solid entrainment in the circulation loop. Sensors for measuring static charge and solid flow in fluidized bed reactors are already available on the market. However, in practical applications, these sensors are often disturbed by noise or false signals, preventing them from reliably measuring these electrostatic charges and solid flow phenomena directly. Therefore, the signals from these sensors have limited value in monitoring the operating conditions of fluidized bed reactors or for efficiency diagnosis. Electrostatic phenomena occur in many equipment used in various industrial processes, such as chemical reactors, equipment for handling granular materials, pipelines, storage tanks, and transport containers, including fluidized bed reactors used for producing various gaseous, liquid, or solid chemical products. The accumulation of static charge on the particulates and/or process components leads to the formation of an electric field, which in turn affects these particles or components through electric forces. Furthermore, when there is enough static charge, electrostatic discharge events may occur, thereby compromising the reliability and safety of production. For example, commercial polyethylene (PE) reactors use a fluidized bed to allow suspended catalyst particles to grow into PE resin particles, thereby converting ethylene gas into polyethylene resin. Collisions between catalyst particles, resin particles, and the reactor wall can cause the particles to become charged; areas on the reactor wall that have an insulating coating or surface deposits may also become charged. When the charge on the particle has the same sign as the overall net charge, the particle is subjected to an electric force directed toward the reactor wall. If this force is strong enough, it can fix the charged catalyst or resin particles to the reactor walls; these particles gradually grow and agglomerate into clumps, which eventually fall off and block the product outlet, causing the reactor to stop operating. Furthermore, if the electric field strength inside the reactor exceeds the breakdown strength of the gas, discharge or sparks may occur in the gas. Any isolated conductor in the reactor can become charged as a result of particle impacts, and these conductors may also discharge sparks to nearby metal objects. Furthermore, if the insulating coating on the reactor wall is charged to a sufficient level, brush discharges that sweep across the inner wall surface may occur. To avoid the hazards of material caking and reactor shutdown caused by the accumulation of large amounts of charge, the industry seeks a charge sensor to monitor the interior of the reactor. Early warnings of caking conditions can help adjust operating parameters to eliminate such caking. The accumulation of a large amount of charge can also lead to the generation of sparks inside the reactor, posing a threat to the reliability of the system. Precise control of fluidized bed reactors requires instruments that can reliably monitor electrostatic phenomena within the system; such instruments can also be combined with algorithms for processing electrostatic signals in order to improve the efficiency and reliability of the system. For example, by calculating the particle entrainment amount in the circulating pipeline, the reaction yield can be determined, and the possibility of blockage in the fluidized bed distributor plates can be reduced ； By detecting changes in signal characteristics, it is possible to determine the likelihood of catalyst poisoning as well as the presence of flow instability phenomena such as large bubbles ； Early warnings for material caking and spark discharge can be issued based on the intensity of the overall signals within the reactor.