Real-time expert system control of anaerobic digestion

1994 ◽  
Vol 30 (12) ◽  
pp. 21-29 ◽  
Author(s):  
D. P. Chynoweth ◽  
S. A. Svoronos ◽  
G. Lyberatos ◽  
J. L. Harman ◽  
P. Pullammanappallil ◽  
...  
Keyword(s):  
Expert System ◽  
Control Strategy ◽  
Control Strategies ◽  
System Control ◽  
Potential Contribution ◽  
Adaptive Optimization ◽  
Line Measurement ◽  
On Line ◽  
Methane Production Rate ◽  
Abnormal Performance

The objective of this research was to develop on-line measurement and feed-back control strategies for evaluation and optimization of a glucose-fed CSTR digester. Using methane yield as a direct on-line measurement, a model and algorithm were developed and applied for feed-back control and adaptive optimization of the digester for temperature. The model and algorithm were modified and integrated into an expert system to use methane production rate and dilution rate to automatically detect and recover digester abnormal performance resulting from underloading, overloading, and addition of an inhibitor (phenol). On-line fluorometric measurement of NADH, which is a measurement of overall microbial activity, was evaluated for its potential contribution to this control strategy.

Control Strategies for a Highly Loaded Biological Ammonia Elimination Process

1993 ◽  
Vol 28 (11-12) ◽  
pp. 531-538 ◽  
Author(s):  
B. Teichgräber
Keyword(s):  
Closed Loop ◽  
Control Strategies ◽  
Level Control ◽  
Sludge Dewatering ◽  
Loop Control ◽  
Reject Water ◽  
Line Measurement ◽  
Control Pattern ◽  
On Line ◽  
Treatment Facilities

A nitrification/denitrification process was applied to reject water treatment from sludge dewatering at Bottrop central sludge treatment facilities of the Emschergenossenschaft. On-line monitoring of influent and effluent turbidity, closed loop control of DO and pH, and on-line monitoring of nitrogen compounds were combined to a three level control pattern. Though on-line measurement of substrate and product showed substantial response time it could be used to operate nitrification/denitrification within process boundaries.

Heat Recovery System Control Strategy to Meet Multiple Transient Demands

2001 ◽  
Author(s):  
H. Perez-Blanco ◽  
Paul Albright
Keyword(s):  
Control Strategy ◽  
Thermal Efficiency ◽  
Power Distribution ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Demand Curve ◽  
Control Strategies ◽  
System Control ◽  
Secondary Control ◽  
Exhaust Heat

As increasing power generation needs are met with gas turbines, it is clear that exhaust heat recovery presents a considerable opportunity to reduce operational costs and enhance thermal efficiency. Typically, a system may provide power, process heat and cooling. However, each utility may have a daily demand curve with peaks that do not necessarily coincide in time. Hence, it is necessary to devise strategies that ensure meeting the needs of each user continually while maintaining high thermal efficiencies. To study these situations, a dynamic model of a system comprising a gas turbine, a heat recovery steam generator, and absorption machine was developed. The transient response of the system was studied to determine the effects of sudden changes in demand. Two control strategies utilizing proportional integral controls were considered. The first strategy relied on operating the turbine to meet the power required by the consumer. When power demands were low and steam and cooling demands high, a secondary control strategy operated the turbine to meet the steam demands, thus maximizing the thermal efficiency of the systemThe first strategy relied on operating the turbine to meet the power required by the consumer. When power demands were low and steam and cooling demands high, a secondary control strategy operated the turbine to meet the steam demands, thus maximizing the thermal efficiency of the system. System control and stability were tested, including simulation of a power distribution network simulating resistive, capacitance and inductive loads.

Effect of co-substrate, biomass and sulfate concentration on the performance of a control strategy used to determine the anaerobic stage length of an anaerobic/aerobic SBR degrading p-nitrophenol

2005 ◽  
Vol 52 (1-2) ◽  
pp. 441-447 ◽  
Author(s):  
G. Buitrón ◽  
G. Moreno ◽  
M.E. García ◽  
J. Moreno
Keyword(s):  
Significant Influence ◽  
Control Strategy ◽  
Reduction Potential ◽  
Biomass Concentration ◽  
Sulfate Concentration ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Acid Ratio ◽  
Line Measurement ◽  
On Line

The effect of the p-nitrophenol to propionic acid ratio, the biomass concentration, and the presence of sulfates on the performance of a control strategy of an anaerobic/aerobic SBR degrading p-nitrophenol was studied. The duration of the anaerobic stage was controlled by an algorithm based on the on-line measurement of the oxidation-reduction potential, which indicates the end of the reduction of p-nitrophenol to p-aminophenol. It was observed that no significant influence on the performance of the algorithm was found when the co-substrate, the biomass concentration and the presence of sulfates were varied, indicating the robustness of the control strategy. Only for the case when a low concentration of co-substrate was used, was there no transformation of p-nitrophenol.

Control Theory Measures of Tracking as Indices of Attention Allocation Strategies

1977 ◽  
Vol 19 (4) ◽  
pp. 349-365 ◽  
Author(s):  
Christopher D. Wickens ◽  
Daniel Gopher
Keyword(s):  
Control Theory ◽  
Reaction Time Task ◽  
Attention Allocation ◽  
System Control ◽  
Time Sharing ◽  
Adaptive Aiding ◽  
Line Measurement ◽  
Serial Reaction ◽  
On Line ◽  
Allocation Strategies

In an intelligent man-machine control system, control theory measures describing the operator's tracking performance can provide useful information concerning an operator's attentional slate. This information may be used to implement adaptive aiding procedures. Research is reviewed that relates attentional manipulations to variation in control theory parameters, and an experiment is then described in which 29 subjects performed a tracking task alone, and concurrently with a serial reaction-time task. Within the time-sharing condition, relative priorities between the two tasks were manipulated. The results are interpreted in terms of the separate effects of time-sharing and of priority manipulations upon measures of tracking gain, remnant, time-delay and response “holds,” and the feasibility of on-line measurement of those variables.

Simple control strategies of methanol dosing for post-denitrification

1998 ◽  
Vol 38 (3) ◽  
pp. 291-297 ◽  
Author(s):  
N. Puznava ◽  
S. Zeghal ◽  
E. Reddet
Keyword(s):  
Control Strategies ◽  
Operating Cost ◽  
Feed Water ◽  
Effluent Quality ◽  
Second Stage ◽  
Point Tracking ◽  
Regulatory Constraints ◽  
Operation Costs ◽  
Line Measurement ◽  
On Line

The objective of this work is to propose a simple but efficient way of controlling the carbon addition for the post-denitrification process in order to comply with regulatory constraints and optimize operating cost. A Biostyr® pilot column filled with polystyrene beads was used for the experiments. In order to simulate a secondary treated water from a nitrifying stage with a carbon source addition, the feed water was composed of river water dosed with nitrates, phosphates and methanol. Methanol was added initially with no control (at different constant rates) and in a second stage with different control strategies based on the on-line measurement of inlet and/or outlet nitrate concentrations. This simple dosing mode proved to be very efficient in set-point tracking to ensure the effluent quality and in minimizing the methanol addition (up to 20% less methanol consumption), thus optimizing operation costs.

On-line expert system for power distribution system control

1992 ◽  
Vol 14 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Yasuo Fujii ◽  
Akihiro Miura ◽  
Akihiro Miura ◽  
Junichiro Tsukamoto ◽  
Michel G. Youssef ◽  
...  
Keyword(s):  
Expert System ◽  
Power Distribution ◽  
Distribution System ◽  
System Control ◽  
Power Distribution System ◽  
On Line

Nonlinear System Control Strategies

2013 ◽  
Vol 694-697 ◽  
pp. 2157-2161
Author(s):  
Cong Li ◽  
Xi Min Liu
Keyword(s):  
Nonlinear System ◽  
Nonlinear Control ◽  
Control Strategy ◽  
Control Method ◽  
Control Strategies ◽  
Liquid Level ◽  
Amplification Coefficient ◽  
System Control ◽  
Nonlinear System Control ◽  
Level Process

A nonlinear model of a liquid level process is obtained on the analysis of its nonlinear characteristics. Then a practical nonlinear system control strategy of the liquid level process based on single chip computer is presented. By measuring the liquid level and flow rate, two key parameters of the liquid level process, the amplification coefficient and time constant under different load are calculated. Then the control signal is calculated according to the selected control method and the automatic control of the nonlinear system is realized. The test results are given and it shows that the nonlinear control strategy is better then the linear control strategy. The nonlinear control strategy can improve control quality considerably.

Model-based evaluation of an on-line control strategy for SBRs based on OUR and ORP measurements

2006 ◽  
Vol 53 (4-5) ◽  
pp. 161-169 ◽  
Author(s):  
Ll. Corominas ◽  
G. Sin ◽  
S. Puig ◽  
A. Traore ◽  
M. Balaguer ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Control Strategy ◽  
Control Strategies ◽  
Mechanistic Model ◽  
Treated Wastewater ◽  
Effluent Quality ◽  
Model Based ◽  
Treatment Technologies ◽  
On Line ◽  
Key Aspects

Application of control strategies for existing wastewater treatment technologies becomes necessary to meet ever-stricter effluent legislations and reduce the associated treatment costs. In the case of SBR technology, controlling the phase scheduling is one of the key aspects of SBR operation. In this study a calibrated mechanistic model based on the ASM1 was used to evaluate an on-line control strategy for the SBR phase-scheduling and compare it with the SBR's performance using no control strategy. To evaluate the performance, reference indices relating to the effluent quality, the required energy for aeration and the treated wastewater volume were used. The results showed that it is possible to maintain optimal SBR performance in the studied system at minimal costs by on-line control of the length of the aerobic and anoxic phases.

Thickness Measurement in the AEM by Macintosh-Based Analysis of Two-Beam Convergent Beam Patterns

1990 ◽  
Vol 48 (2) ◽  
pp. 504-505
Author(s):  
John F. Mansfield ◽  
Douglas C. Crawford
Keyword(s):  
Electron Microscope ◽  
Video Camera ◽  
Thickness Measurement ◽  
Specimen Thickness ◽  
Crystalline Materials ◽  
Beam Dynamic ◽  
Line Measurement ◽  
On Line ◽  
Image Position ◽  
Convergent Beam

A method has been developed that allows on-line measurement of the thickness of crystalline materials in the analytical electron microscope. Two-beam convergent beam electron diffraction (CBED) patterns are digitized from a JEOL 2000FX electron microscope into an Apple Macintosh II microcomputer via a Gatan #673 CCD Video Camera and an Imaging Systems Technology Video 1000 frame-capture board. It is necessary to know the lattice parameters of the sample since measurements are made of the spacing of the diffraction discs in order to calibrate the pattern. The sample thickness is calculated from measurements of the spacings of the fringes that are seen in the diffraction discs. This technique was pioneered by Kelly et al, who used the two-beam dynamic theory of MacGillavry relate the deviation parameter (Si) of the ith fringe from the exact Bragg condition to the specimen thickness (t) with the equation:Where ξg, is the extinction distance for that reflection and ni is an integer.

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