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This paper aims to provide a design of intelligent model‐based topology analyzer that can be used to improve plant operation.
Abstract
Purpose
This paper aims to provide a design of intelligent model‐based topology analyzer that can be used to improve plant operation.
Design/methodology/approach
POOM process modeling methodology is proposed to model and partition plant topology so that plant operation can be designed in effective manner as mapped to plant topology partitions. Plant topology is divided into areas based on the operation required and material flow and isolation paths are identified automatically using intelligent algorithm.
Findings
It is possible to define hierarchical plant structure (topology) partitions that can be mapped to plant operation levels, which are described by ANSI/ISA‐S88. In addition, the use of design knowledge can be useful to define conceptual partitions such as Block, which is essential to link design and operation knowledge. Plant operation (jobs) can be flexibly defined in view of plant structure partitions in terms of resources (materials, plant structural areas) required and operation scheduling.
Research limitations/implications
It is important to link to production scheduling to ensure effective use of topology partitions in real time based on available resources. The proposed approach can be improved via the integration with intelligent production scheduling.
Practical implications
Production and manufacturing plants will be able to use the proposed approach to design and validate plant operation and to improve plant maintenance while reducing operation risks by identifying plant structures required for each operation task. The proposed technique can be helpful to engineers and R&D members to consider in their design and investigation for process safety, risk management, and plant operation and management.
Originality/value
The idea of topology analysis is quite new where it is usually implemented using search algorithms without considering domain knowledge and operation structures. This paper proposes a valuable technique to link plant structure with plant operation hierarchies, which is important for design and engineering practices and R&D activities for plant operation.
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Hamidreza Khodayari, Fathollah Ommi and Zoheir Saboohi
The purpose of this paper is to review the applications of the chemical reactor network (CRN) approach for modeling the combustion in gas turbine combustors and classify the CRN…
Abstract
Purpose
The purpose of this paper is to review the applications of the chemical reactor network (CRN) approach for modeling the combustion in gas turbine combustors and classify the CRN construction methods that have been frequently used by researchers.
Design/methodology/approach
This paper initiates with introducing the CRN approach as a practical tool for precisely predicting the species concentrations in the combustion process with lower computational costs. The structure of the CRN and its elements as the ideal reactors are reviewed in recent studies. Flow field modeling has been identified as the most important input for constructing the CRNs; thus, the flow field modeling methods have been extensively reviewed in previous studies. Network approach, component modeling approach and computational fluid dynamics (CFD), as the main flow field modeling methods, are investigated with a focus on the CRN applications. Then, the CRN construction approaches are reviewed and categorized based on extracting the flow field required data. Finally, the most used kinetics and CRN solvers are reviewed and reported in this paper.
Findings
It is concluded that the CRN approach can be a useful tool in the entire process of combustion chamber design. One-dimensional and quasi-dimensional methods of flow field modeling are used in the construction of the simple CRNs without detailed geometry data. This approach requires fewer requirements and is used in the initial combustor designing process. In recent years, using the CFD approach in the construction of CRNs has been increased. The flow field results of the CFD codes processed to create the homogeneous regions based on construction criteria. Over the past years, several practical algorithms have been proposed to automatically extract reactor networks from CFD results. These algorithms have been developed to identify homogeneous regions with a high resolution based on the splitting criteria.
Originality/value
This paper reviews the various flow modeling methods used in the construction of the CRNs, along with an overview of the studies carried out in this field. Also, the usual approaches for creating a CRN and the most significant achievements in this field are addressed in detail.
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In some fields, research group experiences gained in laboratories are more influential than the classroom in shaping graduate students’ research abilities, understandings of…
Abstract
Purpose
In some fields, research group experiences gained in laboratories are more influential than the classroom in shaping graduate students’ research abilities, understandings of post-graduate careers and professional identities. However, little is known about what and how students learn from their research group experiences. This paper aims to explore the learning experiences of engineering graduate students in one chemical engineering research group to determine what students learned and to identify the practices and activities that facilitated their learning.
Design/methodology/approach
Ethnography was used to observe the experiences of one research group in chemical engineering. Fieldwork included 13 months of observations, 31 formal interviews (16 first-round and 15 second-round interviews) and informal interviews. Fieldnotes and transcriptions were analyzed using grounded theory techniques.
Findings
Research group members developed four dominant competencies: presenting research, receiving and responding to feedback, solving problems and troubleshooting problems. Students’ learning was facilitated by the practices and activities of the research group (e.g. weekly full group and subgroup meetings) and mediated through the interactions of others (i.e. peers, faculty supervisor and lab manager).
Originality/value
This study adds to the engineering education literature and contributes to the larger discourse on identifying promising practices and activities that improve student learning in graduate education.
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Sadia Samar Ali, Rajbir Kaur and Jose Antonio Marmolejo Saucedo
Faheem Ejaz, William Pao and Hafiz Muhammad Ali
In plethora of petroleum, chemical and heat transfer applications, T-junction is often used to partially separate gas from other fluids, to reduce work burden on other separating…
Abstract
Purpose
In plethora of petroleum, chemical and heat transfer applications, T-junction is often used to partially separate gas from other fluids, to reduce work burden on other separating equipment. The abundance of liquid carryovers from the T-junction side arm is the cause of production downtime in terms of frequent tripping of downstream equipment train. Literature review revealed that regular and reduced T-junctions either have high peak liquid carryovers (PLCs) or the liquid appears early in the side arm [liquid carryover threshold (LCT)]. The purpose of this study is to harvest the useful features of regular and reduced T-junction and analyze diverging T-junction having upstream and downstream pipes.
Design/methodology/approach
Volume of fluid as a multiphase model, available in ANSYS Fluent, was used to simulate air–water slug flow in five diverging T-junctions for eight distinct velocity ratios. PLCs and LCT were chosen as key performance indices.
Findings
The results indicated that T (0.5–1) and (0.8–1) performed better as low liquid carryovers and high LCT were achieved having separation efficiencies of 96% and 94.5%, respectively. These two diverging T-junctions had significantly lower PLCs and high LCT when compared to other three T-junctions. Results showed that the sudden reduction in the side arm diameter results in high liquid carryovers and lower LCT. Low water and air superficial velocities tend to have low PLC and high LCT.
Research limitations/implications
This study involved working fluids air and water but applies to other types of fluids as well.
Practical implications
The novel T-junction design introduced in this study has significantly higher LCT and lower PLC. This is an indication of higher phase separation performance as compared to other types of T-junctions. Because of lower liquid take-offs, there will be less frequent downstream equipment tripping resulting in lower maintenance costs. Empirical correlations presented in this study can predict fraction of gas and liquid in the side arm without having to repeat the experiment.
Social implications
Maintenance costs and production downtime can be significantly reduced with the implication of diverging T-junction design.
Originality/value
The presented study revealed that the diameter ratio has a significant impact on PLC and LCT. It can be concluded that novel T-junction designs, T2 and T3, achieved high phase separation; therefore, it is favorable to use in the industry. Furthermore, a few limitations in terms of diameter ratio are also discussed in detail.
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Guus Berkhout, Patrick van der Duin, Dap Hartmann and Roland Ortt
The Cyclic Innovation Model is applied to a new process for the production of fine chemicals and pharmaceuticals using a combination of ionic liquids and supercritical carbon…
Abstract
The Cyclic Innovation Model is applied to a new process for the production of fine chemicals and pharmaceuticals using a combination of ionic liquids and supercritical carbon dioxide. This multi-value innovation combines economic growth with environmental concerns and social value. The most important obstacles in the implementation of this new technology are the successful life cycle management of current production plants, the linearity of current innovation thinking, and a perceived high risk of adoption.
Samaneh Karami, Ataallah Soltani Goharrizi, Bahador Abolpour and Samira Darijani
The purpose of this paper is to present a computational fluid dynamic simulation for the investigation of the particles segregation phenomenon in the gas–solid fluidized beds.
Abstract
Purpose
The purpose of this paper is to present a computational fluid dynamic simulation for the investigation of the particles segregation phenomenon in the gas–solid fluidized beds.
Design/methodology/approach
These particles have the same size and different densities. The k–ε model and multiphase particle-in-cell method have been utilized for modeling the turbulent fluid flow and solid particles behaviors, respectively. The coupled equations of the velocity and pressure have been solved by using a combination of SIMPLE and PISO algorithms. After validating the simulation, different mixing indices, with different calculation bases, have been investigated, and it has been found that the Lacey mixing index, which was defined based on statistical concepts, is suitable to investigate the segregation/mixing phenomena of this bed in different conditions. Finally, the effects of parameters such as velocity, particle density ratio, jetsam concentration, and initial arrangement on the segregation/mixing behaviors of the bed have been studied.
Findings
The results show that the increase in the superficial gas velocity decreases the mixing index to a minimum value and then increases this index in the beds with mixed initial condition, unlike the beds with separated initial condition. Moreover, an increase in the particle density ratio increases the minimum fluidization velocity of the bed, and also the amount of segregation, and increase in the jetsam concentration increases the value of the mixing index.
Originality/value
A computational fluid dynamics simulation has been presented for the particles segregation phenomenon in the gas–solid fluidized beds.
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The purpose of this study is to carry out energy and exergy analysis of fuels. Production of power and heat in industrialized countries is almost entirely based on combustion of…
Abstract
Purpose
The purpose of this study is to carry out energy and exergy analysis of fuels. Production of power and heat in industrialized countries is almost entirely based on combustion of fuels. Usually, combustion takes place in boilers or furnace; well-designed boilers have high thermal efficiencies of > 90 per cent. Even very high efficiencies, close to 100 per cent can be achieved depending on the applied fuel and boiler type. These high thermal efficiencies do suggest that combustion processes are highly optimized and do not need further improvements with regard to their thermodynamic performance. Second law (entropy or exergy) evaluations, however, shows that thermodynamic losses of boiler and furnaces are much larger than the thermal efficiencies do suggest. During combustion, air is predominantly used. When using air, the adiabatic combustion temperature depends only on the properties of fuel and air. The determining parameters for optimal fuel utilization are the fuel type, their composition and moisture content, the air temperature and air factor at combustion inlet.
Design/methodology/approach
Following assumptions are made for the analysis: calculation on the basis of 100 kg of dry and ash free fuel entering the control volume; fuel entering the control volume at T0, P0 and reacting completely with air entering separately at T0, P0 to form CO2, SO2, N2 and H2O, which exit separately at T0, P0 (T0 = 298 K; P0 = 1 atm); all heat transfer occurs at temperature T0; and the chemical exergy of the ash has been ignored The availability change and the irreversibility for chemical reactions of hydrocarbon fuels were studied because fuel and dry air composed of O2 and N2 react to form products of combustion in the restricted dead state, and fuel and dry air composed of O2 and N2 react to form products of combustion which end up in the environmental (unrestricted) dead state. The difference between the above two statement, is the chemical availability of the product gases as they proceed from the restricted to the unrestricted dead state. These evaluations were made in terms of enthalpy and entropy values of the reacting species. T0 extend these concepts to the most general situation, it is considered a steady-state control volume where the fuels enters at the restricted dead state, the air (oxidant) is drawn from the environment, and the products are returned to the unrestricted dead state.
Findings
It is evident from the analysis that an air factor of 1.10-1.20 is sufficient for liquid fuels, whereas solid fuels will require air factors of 1.15–1.3. When the temperatures of the products of combustion (Tp) are cooled down to that of T0, the maximum reversible work occurs. From the analysis, it is clear that the rather low combustion temperature and the need for cooling down the flue gases to extract the required heat are the main causes of the large exergy losses. The maximum second law efficiency also occurs when Tp is set equal to T0. The maximum second law efficiency per kilo mole of fuel is found to be 73 per cent, i.e. 73 per cent of the energy released by the cooling process could theoretically be converted into useful work. It is evident that reducing exergy losses of combustion is only useful if the heat transferred from the flue gas is used at high temperatures. Otherwise, a reduction of exergy loss of combustion will only increase the exergy loss of heat transfer to the power cycle or heat-absorbing process. The exergy loss of combustion can be reduced considerable by preheating combustion air. Higher preheat temperatures can be obtained by using the flue gas flow only for preheating air. The remainder of the flue gas flow can be used for heat transfer to a power cycle or heat-absorbing process. Even with very high air preheat temperatures, exergy losses of combustion are still > 20 per cent. The application of electrochemical conversion of fuel, as is realized in fuel cells, allows for much lower exergy loses for the reaction between fuel and air than thermal conversion. For industrial applications, electrochemical conversion is not yet available, but will be an interesting option for the future.
Originality/value
The outcome of the study would certainly be an eye-opener for all the stakeholders in thermal power plants for considering the second law efficiency and to mitigate the irreversibilities.
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Olivia Rossi and Arvind Chandrasekaran
The purpose of this paper is to answer this question by discussing the practicality of implementing microreactor technology towards large-scale renewable energy generation, as…
Abstract
Purpose
The purpose of this paper is to answer this question by discussing the practicality of implementing microreactor technology towards large-scale renewable energy generation, as well as provide an incentive for future researchers to utilize microreactors as a useful alternative tool for green energy production. However, can microreactors present a viable solution for the generation of renewable energy to tackle the on-going global energy crisis?
Design/methodology/approach
In this paper, the practicality of implementing microreactor technology toward large-scale renewable energy generation is discussed. Specific areas of interest that elucidate considerable returns of microreactors toward renewable energy production are biofuel synthesis, hydrogen conversion and solar energy harvesting.
Findings
It is believed that sustained research on microreactors can significantly accelerate the development of new energy production methods through renewable sources, which will undoubtedly aid in the quest for a greener future.
Originality/value
This work aims to provide a sound judgement on the importance of research on renewable energy production and alternative energy management methods through microreactor technology, and why future studies on this topic should be highly encouraged. The relevance of this opinion paper lies in the idea that microreactors are an innovative concept currently used in engineering to significantly accelerate chemical reactions on microscale volumes; with the feasibility of high throughput to convert energy at larger scales with much greater efficiency than existing energy production methods.
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