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Unburned Combustibles
Published in Charles E. Baukal, Industrial Combustion Pollution and Control, 2003
A number of factors are important to optimize biofiltration performance. Pretreatment of the gas stream is important to remove particulates that would not be treated but would clog the biofilter. Gas distribution is important for achieving uniform flow. Nonuniform flow may reduce VOC removal efficiency where too much flow is going through a section of the biofilter. Proper gas-distribution systems can solve this problem. Another important factor is humidification where too little moisture can cause dry zones and too much moisture can inhibit gas transport. Insufficient moisture can also limit microbial activity [59]. Proper pH control maximizes microbial activity where conditions at or neutral are generally preferred. Temperature control is important where a narrow temperature range is preferred. Temperatures above or below that range reduce microbial activity. The type of VOC to be treated is an important factor in the performance of a biofilter. Some VOCs are more biodegradable than others as shown in Table 7.6. Residence time is also an important factor as fairly long times may be required to achieve high removal efficiencies.
Critical Analysis of Optimization Techniques for a MRPID Thermal System Controller
Published in IETE Journal of Research, 2023
Abhas Kanungo, Monika Mittal, Lillie Dewan
Thermal control system is very important in power industry due to its low fuel cost and requirement of a very small space for its installation [1]. A quick and precise temperature control is very important in multiple scenarios such as chemical reactors, food industry, power industry etc. [2]. A small change in temperature may cause failure of the whole system. Therefore, it is essential to ensure appropriate temperature regulation in a typical thermal system to maintain the desired system performance [3]. Proportional Integral (PI) controller is generally employed in power industry with a fixed structure and steady parameters appropriate for a working environment. Therefore, these controllers are not suitable for a different working environment due to non-straight system components [4]. In addition, dynamic execution of the framework depends on the choice of PI controller gain that is suitable for mechanical control [5]. For instance, the dominant pole placement tuning the method for PI/PID controller is used to control the first- and second-order time delay systems [6]. A fractional-order PID (FOPID) controller for the solution of an adjustment problem was presented in [7]. They proposed a State Transition Algorithm (STA) to analyze the performance of FOPID tuning problems and it was compared to the classical PID control. Fractional-order 2-DOF PI controller is used to design real-time control of heat flow experiment [8]. FOPID, FOIDF, PFOID and PDFOI controllers have been used in modern as well as in hybrid power systems [9–16]. But there are certain associated disadvantages such as need for optimally tuning several controller parameters to get better system dynamics [17] and the performance of FOPID gets affected by noise and disturbances [18]. FOPID can have different filtering effects on error signal based on its parameters [19]. It may deteriorate the system output more often than not.