Invariant Control of Wastewater Aeration

Sniders, Andris; Laizans, Aigars

doi:10.1007/1-4020-5261-8_17

Cited by 3 publications

(8 citation statements)

References 5 publications

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“…For no-load mode (q s = 0, q w = 0) the steam boiler is considered to be two component volume (water + steam) unit with constant sensitivity and response parameters. In that case the transient process of pressure alteration can be described by second-order transfer function: (1) where Q f (s), p 0 (s) -Laplace transforms of furnace heat flow and steam pressure at no-load mode; η sb = 0.93 -efficiency factor of the boiler, using economizer; K sb = 11.5 bar·MW The heat power actuator consists of frequency converter; servomechanism with servomotor and feedback for stability improvement, gas and air valves; and furnace. According to the block-diagram (Fig.…”

Section: Mathematical and Simulation Modelsmentioning

confidence: 99%

“…Oxygen is supplied to the aeration tank using air blowers driven by variable-frequency electric motors. Thus, the inverter output frequency is the response to the dissolved oxygen concentration measured at the aeration tank exit [1]. As a wastewater aeration system is the main energy consumerup to 80 % of wastewater processing plant, high control parameter level substantially increases the energy consumption and total expenses.…”

Section: Introductionmentioning

confidence: 99%

“…The main task of aerator control system is to keep dissolved oxygen concentration high enough -usually around 2g·m -3 [1], [2]. Major perturbation that has direct impact on oxygen concentration over all aeration tank volume is variable wastewater afflux, and waste concentration in incoming wastewater.…”

Section: Introductionmentioning

confidence: 99%

“…PID controllers are widely used for wastewater aeration process automation, but the research shows low control quality and inability to respond adequately to both main perturbation variations because of several variables to be controlled [1], [2]. This is also the reason of keeping high dissolved oxygen concentration set points at the aeration tank exit.…”

Section: Introductionmentioning

confidence: 99%

“…Aeration tank inertia is between 40 and 90 minutes, depending on afflux and aeration tank size, sensitivity changes with waste concentration and waste composition. Adaptive PID-DPC control system, the parameters of which are correctly calculated according to the invariant control principle, cancels out the impact of perturbationsfluctuating waste concentration and afflux [1], [2].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Invariant Control of the Technological Plants to Compensate an Impact of Main Disturbances Preemptively

Sniders

Laizans

Komass

2016

Latvian Journal of Physics and Technical Sciences

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The paper considers a survey of the research procedures and results due to invariant control method application perspective for operation quality advancement in several technological plants (wastewater biological treatment tanks and water steam production boilers), which operate under influence of organised and random disturbances. A specified subject of research is the simulation model of the multi-link invariant control system for steam pressure stabilisation in a steam boiler by preemptive compensation of steam load and feed water flow impact on output parameter (steam pressure), developed in MATLAB/SIMULINK. Simulation block-diagram of the steam boiler invariant control system, containing closed loop PID control circuit and open loop DPC circuit, has been composed on the basis of the designed mathematical model of the system components, disturbance compensation algorithms, and operational equation of the invariant control system. Comparative response of the steam boiler, operating under influence of fluctuating disturbances, with conventional PID control and using PID-DPC control with disturbance compensation controller DPC, has been investigated. Simulation results of invariant PID -DPC control system show that output parameter of the steam boilerpressure remains practically constant under fluctuating disturbances due to a high-speed response of DPC controller.

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Section: Mathematical and Simulation Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Invariant Control of the Technological Plants to Compensate an Impact of Main Disturbances Preemptively

Sniders

Laizans

Komass

2016

Latvian Journal of Physics and Technical Sciences

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Adaptive Model of Wastewater Aeration Tank

Sniders¹,

Laizans²

2011

Scientific Journal of Riga Technical University. Environmental and Climate Technologies

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-The paper discusses the methodology of oxygen transfer virtual simulation in a wastewater biological treatment process, using the MATLAB/SIMULINK technology. A selftuning adaptive model of a wastewater aeration tank, as a nonstationary object, with variable time dependent sensitivity and inertia indexes, as the functions of input variable -air pneumatic supply capacity L g (t) (m 3 /min), output variable -dissolved oxygen concentration C(t) (g/m 3 ) and oxygen expenditure, as a load -q(t) (g/min), required for wastewater complete purification, is expounded. Virtual models, applying Laplace transforms and SIMULINK blocks library, are composed in order to compare the transient processes of dissolved oxygen concentration in the simplified stationary model with constant sensitivity and inertia coefficients, and in the non-stationary model with variable sensitivity and inertia indexes. The simulation block-diagram for non-stationary model adoption to the variable parameters is developed, using informative links from input variable L g (t), from variable load q(t) and feedback from output variable C(t) as inputs of calculation modulus, allowing to instantly re-calculate the variable indexes during simulation time. Comparison of the simplified stationary model and the non-stationary model shows that the simulation results of oxygen transfer differ up to 50%.

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Invariant Method of Load Independent Pressure Control in Steam Boiler

Sniders¹,

Komass²

2012

Electrical, Control and Communication Engineering

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The paper considers the possibility of steam production and supply process improvement by perfection of the steam boiler control system, applying invariance principle that makes possible preemptive compensation of the influence of steam expenditure as a disturbance on the control process quality and efficiency. For the development of invariant control system, the mathematical modeling and simulation in MATLAB - SIMULINK environment is made. The control unit is low pressure steam boiler with one input impact to control - the heat flow of burning gas mixture fuel, one measured output parameter of the process - the steam pressure, and the main disturbance as a load impact - the steam expenditure. The mathematical and virtual models and block-diagrams for transient process simulation is compiled, allowing to start practical design and investigation of steam boiler invariant control system with high operation stability under essentially fluctuating load. The simulation results prove that the optimal solution for the transient process improvement in steam boiler, taking in account fluctuating load, is invariant PID-DPC two loop control system with disturbance impact on steam pressure preemptive compensation. Under invariant control the steam pressure overshoots decreases substantially in comparison with the traditional PID-feedback control method.

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Invariant Control of Wastewater Aeration

Cited by 3 publications

References 5 publications

Invariant Control of the Technological Plants to Compensate an Impact of Main Disturbances Preemptively

Invariant Control of the Technological Plants to Compensate an Impact of Main Disturbances Preemptively

Adaptive Model of Wastewater Aeration Tank

Invariant Method of Load Independent Pressure Control in Steam Boiler

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