scholarly journals Application of Mathematical Modelling to Reducing and Minimising Energy Requirement for Oxygen Transfer in Batch Stirred Tank Bioreactors

2019 ◽  
Vol 3 (1) ◽  
pp. 14 ◽  
Author(s):  
John Fitzpatrick ◽  
Franck Gloanec ◽  
Elisa Michel ◽  
Johanna Blondy ◽  
Anais Lauzeral
Keyword(s):  
Total Energy ◽  
Oxygen Transfer ◽  
Energy Savings ◽  
Energy Requirement ◽  
Minimum Energy ◽  
Power Input ◽  
Minimum Total Energy ◽  
And Control ◽  
Manipulation And Control ◽  
Selection Of

In this study, microbial kinetic and oxygen transfer modelling coupled with energy analysis was applied to investigate how manipulation and control of agitator power input and air flowrate can reduce and minimise the total energy requirement in a batch aerobic bioprocess subject to constraints. The study showed that major energy savings can be made by appropriate selection of these variables and how they are controlled throughout a bioprocess. In many bioprocesses, the oxygen concentration in the liquid is controlled at a constant value. This may be achieved by maintaining the agitator power at a constant value and varying the air flowrate or vice versa, or by continuously varying both. The modelling showed that the minimum or near-minimum total energy requirement occurred when operating at the onset of impeller flooding throughout the bioprocess by continuously varying both impeller power and air flowrate over the bioprocess time. Operating at the onset of flooding may not be practical to implement in practice. However, the minimum energy can be approached by dividing the bioprocess time into a small number of time segments with appropriately chosen constant agitator powers and varying the air flowrate within each segment. This is much more practical to implement.

scholarly journals Insights from Mathematical Modelling into Process Control of Oxygen Transfer in Batch Stirred Tank Bioreactors for Reducing Energy Requirement

2020 ◽  
Vol 4 (2) ◽  
pp. 34 ◽  
Author(s):  
John J. Fitzpatrick ◽  
Franck Gloanec ◽  
Elisa Michel
Keyword(s):  
Oxygen Transfer ◽  
Energy Savings ◽  
Energy Requirement ◽  
Minimum Energy ◽  
Stirred Tank ◽  
Time Segment ◽  
Control Approach ◽  
Working Volume ◽  
Batch Bioreactors ◽  
Sudden Decrease

Significant energy savings can be made in aerobic stirred tank batch bioreactors by the manipulation of agitator power (Pag) and air flowrate per unit working volume (vvm). Control is often implemented to maintain the oxygen concentration in the bioreaction liquid (COL) at a constant value. This work used model simulations to show that controlling the Pag and vvm continuously over time, such that it is operated at or near the impeller flooding constraint results in the minimum energy requirement for oxygen transfer (strategy Cmin); however, this might prove impractical to control and operate in practice. As an alternative, the work shows that dividing the bioreaction time into a small number of constant Pag time segments (5–10), where a PID controller is used to control vvm to maintain COL constant in each segment, can achieve much of the energy saving that is associated with Cmin. During each time segment, vvm is increased and a sudden decrease in COL is used to detect the onset of flooding, after which there is a step increase in Pag. This sequence of Pag step increases continues until the bioreaction is completed. This practical control approach was shown to save most of the energy that is associated with Cmin.

scholarly journals Improved process modifications of aqueous ammonia-based CO2 capture system

2019 ◽  
Vol 268 ◽  
pp. 02004 ◽  
Author(s):  
Christine Ann Obek ◽  
Foster Kofi Ayittey ◽  
Agus Saptoro
Keyword(s):  
Total Energy ◽  
Co2 Capture ◽  
Large Scale ◽  
Energy Savings ◽  
Aqueous Ammonia ◽  
Energy Requirement ◽  
Vapor Compression ◽  
Total Energy Consumption ◽  
Capture Process ◽  
High Volatility

Extensive research works on CO2 capture process using MEA have been carried out and showed promising results. Nevertheless, it has been acknowledged that the use of MEA is associated with high cost, solvent degradation issues and corrosion. The issues above have motivated researchers to explore and test other potential solvents such as aqueous ammonia (NH3). As result, NH3 based CO2 capture systems have recently attracted much attention as an alternative to MEA based counterparts. Despite their encouraging applications, high volatility of NH3 raise concerns on the energy requirement related to the solvent recovery. Consequently, energy efficient NH3 based CO2 capture systems by modifying the process is desirable. This study, therefore, aims to propose and evaluate three different stand-alone process configurations of absorption-desorption processes in a NH3-based system and compare them with the traditional absorption-desorption system in respect to total energy consumption. These modifications include Rich Solvent Split (RSS), Lean Vapor Compression (LVC), and Rich Vapor Compression (RVC). Results indicate that among these three proposed process modifications, LVC led to the highest reboiler energy savings of 38.3% and total energy savings of 34.5% compared to NH3 based conventional configuration. These findings can serve as essential recommendations for further studies on and large-scale implementations of aqueous NH3 as a better solvent.

Microactuators for Fluidic Applications: Principles, Devices, and Systems

2009 ◽  
Vol 6 (4) ◽  
pp. 250-264
Author(s):  
Nadja Adamovic ◽  
Ioanna Giouroudi ◽  
Jovan Matovic ◽  
Zoran Djinovic ◽  
Ulrich Schmid
Keyword(s):  
Environmental Control ◽  
Research Work ◽  
Microfluidic Devices ◽  
Processing Technologies ◽  
Voltage Frequency ◽  
And Control ◽  
Chemical Process Control ◽  
Manipulation And Control ◽  
Opening Up ◽  
Selection Of

Much effort in microfluidics research has been aimed at designing microscale pumps, valves, switches, dispensers, mixers, filters, separators, and so on, which have a major role in the development of innovative systems like chemical process control, bioanalytical devices, medical drug delivery systems, environmental control, and others. Most of these microfluidic devices have one thing in common: the need for precise manipulation and control of small amounts of fluids. MEMS/NEMS research is continuously opening up new knowledge on modeling approaches, novel materials, and MEMS/NEMS processing technologies that stimulate and accelerate the development of new actuation principles and novel actuator configurations. This review paper presents research work on different actuation techniques that are used for the whole range of microfluidic applications. It covers thermomechanical and electrochemical actuation principles, as well as actuation induced with external electric or magnetic fields. It presents a brief explanation of the operating principle of each type of actuator, actuator configuration, its main characteristics, like power consumption, operational voltage, frequency range, and working fluids, and a discussion of comparisons among different actuation schemes. This study compiles and provides some basic guidelines for selection of the actuation schemes that are currently implemented in microfluidic devices.

scholarly journals Insights from Mathematical Modelling into Energy Requirement and Process Design of Continuous and Batch Stirred Tank Aerobic Bioreactors

2019 ◽  
Vol 3 (3) ◽  
pp. 65
Author(s):  
John J. Fitzpatrick
Keyword(s):  
Oxygen Transfer ◽  
Energy Requirement ◽  
Electrical Energy ◽  
Stirred Tank ◽  
Input Design ◽  
Trade Offs ◽  
Design Variables ◽  
Minimum Total Energy ◽  
Working Volume ◽  
Aerobic Bioreactors

Bioreaction kinetics, oxygen transfer and energy modelling were applied to stirred tank aerobic bioreactors. This was done to investigate how key input design variables influence bioreactor size, feed and wasted substrate, and electrical energy requirements for aeration and cooling, and to compare batch and continuous modes of operation. Oxygen concentration in the liquid is a key input design variable, but its selection is challenging as it can result in design trade-offs. Reducing its value caused a decrease in electrical energy requirement, however this tended to increase the working volume of the bioreactor. The minimum or near-to-minimum total energy requirement for oxygen transfer occurred when operating at the onset of flooding throughout the bioreaction time. For typical KS values, continuous mode of operation required a much smaller bioreactor volume, due to higher operating cell concentration, and this is a major advantage of continuous over batch.

The Turing Machine Model of Sensing, Manipulation, and Control

1989 ◽  
Author(s):  
Constantine Tsikos ◽  
Tom Chmielewski ◽  
Brian Frederick
Keyword(s):  
Turing Machine ◽  
Machine Model ◽  
And Control ◽  
Manipulation And Control

MODEL OF SOCIAL POTENTIAL OF CHILDHOOD IN THE RUSSIAN REGIONS: THE RESULTS OF EXPERIMENTS

2019 ◽  
pp. 152-162
Author(s):  
A.G. Filipova ◽  
A.V. Vysotskaya
Keyword(s):  
Third Wave ◽  
Russian Regions ◽  
The Third ◽  
Control Factors ◽  
Social Potential ◽  
System Input ◽  
Optimal Values ◽  
Fixed Ideal ◽  
And Control ◽  
Selection Of

The article presents the results of mathematical experiments with the system «Social potential of childhood in the Russian regions». In the structure of system divided into three subsystems – the «Reproduction of children in the region», «Children’s health» and «Education of children», for each defined its target factor (output parameter). The groups of infrastructure factors (education, health, culture and sport, transport), socio-economic, territorial-settlement, demographic and en-vironmental factors are designated as the factors that control the system (input parameters). The aim of the study is to build a model îf «Social potential of childhood in the Russian regions», as well as to conduct experiments to find the optimal ratio of the values of target and control factors. Three waves of experiments were conducted. The first wave is related to the analysis of the dynam-ics of indicators for 6 years. The second – with the selection of optimal values of control factors at fixed ideal values of target factors. The third wave allowed us to calculate the values of the target factors based on the selected optimal values of the control factors of the previous wave.

Energy savings potential of new aeration system: Full scale trials

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
A. Lazić ◽  
V. Larsson ◽  
Å. Nordenborg
Keyword(s):  
Control System ◽  
Energy Consumption ◽  
Total Energy ◽  
Energy Savings ◽  
Treatment Plant ◽  
Full Scale ◽  
Total Energy Consumption ◽  
Aeration System ◽  
Fine Bubble ◽  
Aeration Control

The objective of this work is to decrease energy consumption of the aeration system at a mid-size conventional wastewater treatment plant in the south of Sweden where aeration consumes 44% of the total energy consumption of the plant. By designing an energy optimised aeration system (with aeration grids, blowers, controlling valves) and then operating it with a new aeration control system (dissolved oxygen cascade control and most open valve logic) one can save energy. The concept has been tested in full scale by comparing two treatment lines: a reference line (consisting of old fine bubble tube diffusers, old lobe blowers, simple DO control) with a test line (consisting of new Sanitaire Silver Series Low Pressure fine bubble diffusers, a new screw blower and the Flygt aeration control system). Energy savings with the new aeration system measured as Aeration Efficiency was 65%. Furthermore, 13% of the total energy consumption of the whole plant, or 21 000 €/year, could be saved when the tested line was operated with the new aeration system.

scholarly journals The dynamic of body and brain co-evolution

2021 ◽  
pp. 105971232199468
Author(s):  
Paolo Pagliuca ◽  
Stefano Nolfi
Keyword(s):  
Morphological Traits ◽  
The Body ◽  
Morphological Variations ◽  
And Control ◽  
Selection Of

We introduce a method that permits to co-evolve the body and the control properties of robots. It can be used to adapt the morphological traits of robots with a hand-designed morphological bauplan or to evolve the morphological bauplan as well. Our results indicate that robots with co-adapted body and control traits outperform robots with fixed hand-designed morphologies. Interestingly, the advantage is not due to the selection of better morphologies but rather to the mutual scaffolding process that results from the possibility to co-adapt the morphological traits to the control traits and vice versa. Our results also demonstrate that morphological variations do not necessarily have destructive effects on robots’ skills.

scholarly journals ProReal®: The ‘good enough’ online alternative to face-to-face Dramatherapy

Dramatherapy ◽  
2021 ◽  
pp. 026306722110208
Author(s):  
Claire Anne Quigley
Keyword(s):  
Ambiguity Tolerance ◽  
Face To Face ◽  
On Line ◽  
And Control ◽  
Selection Of

The Covid-19 restrictions have limited the access of face-to face therapies for many people and continues to effect how Dramatherapists operate. The following article offers reflections around adapting to an on-line medium, focusing more specifically around the software of ProReal. Limitations and considerations are acknowledged, including technological difficulties, computer efficacy, ambiguity tolerance and the need for careful contracting and reassurance of autonomy and control when using on-line platforms. The article ends with a short selection of vignettes from ProReal sessions.

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