Improving the efficiency of fluidized bed comminution of limestone samples

Author(s):  
D. Wysocki

Purpose: The aim of the research was to describe the properties and methods of using limestone for desulfurization of flue gases and to analyse the process of fluidized bed comminution and the influence of selected parameters and stand modification on quality of product of fluidized bed comminution. Design/methodology/approach: Tests of the grinding process on the fluidized bed were carried out using a modified fluid bed mill for operational variable parameters and their results were compared with the results received before modification. The modification of the test stand consisted of increasing the height of the grinding chamber, which ensured an increase in the volume of the fluidized layer where the grinding process takes place. Findings: Main parameters that determined the effects of comminution in the analyzed case were: overpressure of working air and the rotor speed of the classifier. The introduction of the modifications of the test stand ensured an increase in the volume of the fluidized layer in which the grinding process takes place. As well as a greater gravitational classification, which caused larger grains to be stopped in the grinding chamber and shift of characteristics of grain compositions towards finer grains. Research limitations/implications: It is assumed that the diameter of sorbent grains used in the fluidized bed can not exceed 6 mm. The granularity of the offered sorbents ranges from 0.1 mm to 1.2 mm. The quality of the desulfurization process depends on the overall granulation of used sorbent grains. Practical implications: Appropriately selected sorbent grains used in wet and dry flue gas desulphurisation plants ensure improved efficiency of the desulphurisation process and lower operating costs of the installation. Originality/value: Thanks to the comminution method used, a sorbent is obtained without impurities and with an increased specific surface, which can be used in fluidized bed boilers.

2019 ◽  
Vol 118 ◽  
pp. 02011
Author(s):  
Su Pan ◽  
Yu Pengfeng ◽  
Linbo Liu ◽  
Han Jing ◽  
Xiao Shen

The coal as fired, with unidentified characteristics of the coal gangue, was burned on a 300MW circulating fluidized bed unit. The equipment of the coal conveying system was damaged and the boiler operation was unstable. In response to the problems, the coal quality data and storage conditions of the coal were examined and the site was spot-checked to evaluate the coal quality characteristics. At the same time, the typical representative parameters of the coal handling system and boiler operation were selected. According to the analysis of coal quality and coal storage, the coal quality fluctuates greatly and the uniformity of particle size distribution is poor. There is actually the coal gangue with hard texture and hard to grind in the coal pile. The coal gangue will have adverse effects on the fine screening machine, fine crusher and other equipment. After burned this type of coal, the fluidized quality of the boiler bed is degraded to make an impact on the safe and stable operation of the boiler. It is recommended that the coal should be screened and then burned into the furnace to ensure safe and stable operation of the boiler.


Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1492
Author(s):  
Vladimir Kodnyanko ◽  
Stanislav Shatokhin ◽  
Andrey Kurzakov ◽  
Lilia Strok ◽  
Yuri Pikalov ◽  
...  

The disadvantage of aerostatic bearings is their low dynamic quality. The negative impact on the dynamic characteristics of the bearing is exerted by the volume of air contained in the bearing gap, pockets, and microgrooves located at the outlet of the feeding diaphragms. Reducing the volume of air in the flow path is a resource for increasing the dynamic quality of the aerostatic bearing. This article presents an improved design of an axial aerostatic bearing with simple diaphragms, an annular microgroove, and an elastic suspension of the movable center of the supporting disk. A mathematical model is presented and a methodology for calculating the static characteristics of a bearing and dynamic quality indicators is described. The calculations were carried out using dimensionless quantities, which made it possible to reduce the number of variable parameters. A new method for solving linearized and Laplace-transformed boundary value problems for transformants of air pressure dynamic functions in the bearing layer was applied, which made it possible to obtain a numerical solution of problems sufficient for practice accuracy. The optimization of the criteria for the dynamic quality of the bearing was carried out. It is shown that the use of an elastic suspension of the support center improves its dynamic characteristics by reducing the volume of compressed air in the bearing layer and choosing the optimal volume of the microgroove.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 746
Author(s):  
Magdalena Turk ◽  
Rok Šibanc ◽  
Rok Dreu ◽  
Maja Frankiewicz ◽  
Małgorzata Sznitowska

This study concerned the quality of mini-tablets’ coating uniformity obtained by either the bottom spray chamber with a classical Wurster distributor (CW) or a swirl distributor (SW). Mini-tablets with a diameter of 2.0, 2.5, and 3.0 mm were coated with hypromellose using two different inlet air distributors as well as inlet airflow rates (130 and 156 m3/h). Tartrazine was used as a colorant in the coating layer and the coating uniformity was assessed by spectrophotometric analysis of solutions obtained after disintegration of the mini-tablets (n = 100). Higher uniformity of coating material distribution among the mini-tablets was observed in the case of SW distributor, even for the biggest mini-tablets (d = 3.0 mm), with an RSD no larger than 5.0%. Additionally, coating thickness was evaluated by colorimetric analysis (n = 1000), using a scanner method, and expressed as a hue value. A high correlation (R = 0.993) between inter-tablet variability of hue and UV-Vis results was obtained. Mini-tablets were successfully coated in a fluid bed system using both a classical Wurster distributor as well as a swirl generator. However, regardless of the mini-tablets’ diameter, better film uniformity was achieved in the case of a distributor with a swirl generator.


2021 ◽  
pp. 109634802110115
Author(s):  
Seonjeong (Ally) Lee ◽  
Ning-Kuang Chuang

The physical environment plays an essential role in customers’ hotel stay experiences. Hotels offer a differentiated atmosphere that creates favorable customers’ evaluations. Based on the significant role of environmental cues, this study investigates the effects of an expanded servicescape on customers’ evaluations, including customer satisfaction, quality of life, and customer loyalty, in the context of the hotel industry. To test the proposed research framework, this study collects data from previous hotel customers and conducts a self-administered, online survey. Findings identified ambience, interactions with employees, authenticity, and fascination positively influenced customers’ satisfaction, which further influenced customer loyalty. Only ambience and fascination positively influenced quality of life, which in turn influenced customer loyalty. Results contributed to the application of expanded servicescape in the hotel context. Results also suggested practical implications of the holistic approach of servicescape in the hotel industry.


2020 ◽  
Vol 28 (2) ◽  
pp. 119-133
Author(s):  
Nicola Davies ◽  
Teresa Burdett

PurposeIntegrated healthcare is a central tenant of the NHS Long Term Plan (NHS, 2019). NICE in 2019 published guidelines; advising the integration of multidisciplinary professionals which may lead to an improvement in conservative treatment methods of pelvic organ prolapse. Therefore, current literature on the conservative treatments for pelvic organ prolapse needs to be reviewed to ascertain if an integrated approach would improve the symptoms and quality of life for women.Design/methodology/approachA systematic review of the literature between 2013 and 2018 was implemented. Papers included were written in English, peer-reviewed and consisted of treatments of pelvic organ prolapse in women. Papers containing surgical interventions, postpartum participants, reviews, evaluations, guidelines, follow-up studies, focusing on cost effectiveness, sexual function were excluded.FindingsSeven studies in total were included, and two overarching themes were identified: quality of life after treatment and the effect of conservative treatment on pelvic organ prolapse symptoms. The literature suggested that integrating care had a more positive outcome on pelvic organ symptoms and quality of life.Research limitations/implicationsTo develop a robust enhanced model of care for conservative treatment of pelvic organ prolapse through more mixed method or qualitative research, that incorporates integrative treatment methods with collaboration from multidisciplinary professionals.Practical implicationsThe practical implications of integrating the conservative management of pelvic organ prolapse is the communication between the multidisciplinary team must be exceptional to ensure everyone understands and agrees the treatment that is being provided to patient. Also, effective teamwork is important to ensure the patient receives the best care with input from the correct disciplines. The multi-professional team will need to have regular meetings to discuss and implement care plans for patients that might prove difficult to schedule due to differing commitments and priorities. This must be overcome to insure a successful and effective integrated approach to pelvic organ prolapse is delivered.Social implicationsThe social implications of integrating the professional approach to women's care of pelvic organ prolapse involves reducing the severity of the symptoms therefore, increasing the quality of life. This may result in the reduction of surgical intervention due to the patient being satisfied with the conservative management. Through integrating the management of the prolapse the patient will receive an accessible individualised care plan pathway that focuses on treating or reducing the impact of the symptoms that are bothersome to the patient whilst managing patient expectations. Patients will also, be reassured by the number of multi-disciplinary professionals involved in their care.Originality/valueGlobal integration of conservative treatments and multidisciplinary-professionals specialising in pelvic organ prolapse and pelvic floor dysfunction is needed.


2015 ◽  
Vol 14 (4) ◽  
pp. 164-172 ◽  
Author(s):  
Jacek M. Łączny ◽  
Sebastian Iwaszenko ◽  
Krzysztof Gogola ◽  
Andrzej Bajerski ◽  
Tomasz Janoszek ◽  
...  

2016 ◽  
Vol 36 (3/4) ◽  
pp. 242-257 ◽  
Author(s):  
Erika Cudworth

Purpose – The purpose of this paper is to map the field of sociological animal studies through some examples of critical and mainstream approaches and considers their relation to advocacy. It makes the argument that while all these initiatives have made important contributions to the project of “animalising sociology” and suggest a need for change in species relations, the link between analysis and political strategy is uncertain. Design/methodology/approach – The paper develops its argument by using secondary sources, reviewing sociological positions and offering illustrations of possible interventions. Findings – Sociological interventions in the field of animal studies have been informed by critical perspectives, such as feminism and Marxism, or taken less critical routes deploying actor-network theory and symbolic interactionism. Whilst those working in critical traditions may appear to have a more certain political agenda, an analysis of “how things are” does not always lead to a clear position on “what is to be done” in terms of social movement agendas or policy intervention. In addition, concepts deployed in advocacy such as “liberation”, “quality of life” or “care” are problematic when applied beyond the human. Despite this, there are possibilities for coalition and solidarity around certain claims for change. Research limitations/implications – If the central argument of the paper were taken seriously by general sociologists, then sociology may be more open to “animal studies”. In implications for exisitng sociological animal studies scholarship is to trouble some of the certainties around advocacy. Practical implications – If the central argument of the paper were taken seriously by advocacy groups, then the hiatus between “welfarism” and “liberation” might be overcome. Originality/value – There have been recent attempts to map the field of scholarship in animal studies, but surprisingly little consideration of how different emergent positions inform questions of advocacy and the possibilities for political intervention.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mahmoud Fatouh ◽  
Ayowande A. McCunn

Purpose This paper aims to present a model of shareholders’ willingness to exert effort to reduce the likelihood of bank distress and the implications of the presence of contingent convertible (CoCo) bonds in the liabilities structure of a bank. Design/methodology/approach This study presents a basic model about the moral hazard surrounding shareholders willingness to exert effort that increases the likelihood of a bank’s success. This study uses a one-shot game and so do not capture the effects of repeated interactions. Findings Consistent with the existing literature, this study shows that the direction of the wealth transfer at the conversion of CoCo bonds determines their impact on shareholder risk-taking incentives. This study also finds that “anytime” CoCos (CoCo bonds trigger-able anytime at the discretion of managers) have a minor advantage over regular CoCo bonds, and that quality of capital requirements can reduce the risk-taking incentives of shareholders. Practical implications This study argues that shareholders can also use manager-specific CoCo bonds to reduce the riskiness of the bank activities. The issuance of such bonds can increase the resilience of individual banks and the whole banking system. Regulators can use restrictions on conversion rates and/or requirements on the quality of capital to address the impact of CoCo bonds issuance on risk-taking incentives. Originality/value To model the risk-taking incentives, authors generally modify the asset processes to introduce components that reflect asymmetric information between CoCo holders and shareholders and/or managers. This paper follows a simpler method similar to that of Holmström and Tirole (1998).


2016 ◽  
Vol 106 (01-02) ◽  
pp. 44-50
Author(s):  
T. Lierse ◽  
B. Karpuschewski ◽  
T. R. Kaul

Dieser Beitrag zeigt, dass die durch die Abrichtparameter erzeugte Schleifscheibentopographie nicht nur die Oberflächengüte des Werkstücks, sondern auch dessen Eigenspannungszustand in der Werkstückrandzone in weiten Grenzen verändert. Die Untersuchungen zum Abrichten von Korundschleifscheiben mit einer CVD-Diamantformrolle stellen den Zusammenhang zwischen dem Abrichten unterschiedlicher Schleifscheiben zur Bauteilqualität in Form der Oberflächenrautiefe und randzonennahen Eigenspannungen her.   The quality of the workpiece rim is changed by every grinding process. The grinding wheel topography created by the dressing process has not only influence on the workpiece roughness but also on the surface integrity. The pointed research using aluminum oxide abrasive wheels dressed by CVD diamond dressing discs shows a correlation between the dressing parameters, the workpiece roughness and the surface integrity.


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