Modeling and control of level control process — A comparative study
Tank level control systems are everywhere. All of our process industries mostly depends on this tank level control systems. This paper deals with the modeling and control of a two tank liquid level control system. The considered non linear system is a Single Input Single Output (SISO) system. The goal of the level control is to track the desired level of liquid in to the second tank by controlling the flow rate of the first tank. The tanks are coupled in the interacting and non-interacting ways and a comparison is made between these two systems. The mathematical modeling is done by mass balance method and the PID controller is designed by the trial and error method. The system is simulated with both open loop and closed loop conditions. A comparative study of the time domain response of the two systems while using the PID controller is done by the MATLAB simulation.
Experimentation with an adaptive waterfall controller with disturbance effect
The control systems whose output variable is slow requires more efficient control actions, in this line, there are the cascade-type controllers, which prevent the disturbances in the input of the process from manifesting in the output, currently the analysis are reflected in many investigations, but in a simulated way, and there are a few studies where the implementation is carried out at the didactic level, which allows to perform the verification of the simulations, and to observe the effect that this type of control has when is going to work in a real way, so we can prove the theories and affirmations of the scientific community. In this research, we complete the development of an adaptive cascadetype controller in the two control loops, in a didactic equipment that allows perturbations. To achieve the objectives, we obtained the mathematical modeling of the system, the controllers were designed, the control algorithm is implemented in a plant, whose variables are level and flow, and the effect that these controllers have on perturbations that are made to the process variables. During the implementation of the control algorithm, it was possible to verify that these types of controllers cause that the perturbations that are made at the input of the process were minimun reflected in the output variable. Keywords– Adaptive Control, Cascade, Didactic, Disturbances. Digital Object Identifier (DOI): http://dx.doi.org/10.18687/LACCEI2019.1.1.266 ISBN: 978-0-9993443-6-1 ISSN: 2414-6390
Parboiled rice effluent: A wastewater niche for microalgae and cyanobacteria with growth coupled to comprehensive remediation and phosphorus biofertilization
Abstract The potential of microalgae and cyanobacteria for bioremediation of wastewater by nutrient uptake combined with simultaneous biomass production is a well recognized perception of today's world. The present study illustrates the treatment of a highly polluted wastewater generated during parboiling of paddy in rice mill industries, widely operational in developing countries where rice is the staple food crop, with the help of microalgal and cyanobacterial isolates capable of growing at high rates in parboiled rice mill effluent (RME). This endeavor leads to comprehensive bioremediation of the said effluent and subsequent use of the harvested biomass as slow release phosphorus biofertilizers and the treated effluent for crop irrigation. The RME-acclimatized algal consortium demonstrated highest growth in terms of fresh weight and greatest remediation efficiency at the end of 36 days' treatment of RME, with 93.9% phosphorus and 100% ammonia-nitrogen removal, 98.7%, 91.6% and 93.5% reduction in biological oxygen demand, chemical oxygen demand and total dissolved solid, respectively, and an increment of 186 ± 0.3 mg L − 1 dissolved oxygen, bringing down the pollutants level well below the discharge limits suggested by Central Pollution Control Board, India. Additionally, microalgae in the consortium aggregated in clumps spontaneously in presence of the filaments of Phormidium sp. facilitating easy harvest. The RME-acclimatized algal consortium demonstrated highest accumulation of polyphosphate (poly-P) (0.76 ± 0.01% of dry weight) as well as highest release of phosphorus in non-sterile soil emphasizing the essential role of soil phosphorus solubilizing organisms to leach soluble phosphorus from the insoluble poly-P present in the biomass. The rice seedlings watered with treated RME also showed improved growth effect on shoot height and leaf width. The study results establish the suitability of RME as an excellent growth media for microalgae and cyanobacteria.