Optimization of Vapor Phase Pyridine Synthesis Hindered by Rapid Catalyst Deactivation

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Suresh Kumar Reddy Kuppi Reddy ◽  
Inkollu Sreedhar ◽  
Kondapuram Vijaya Raghavan ◽  
Shivanand Janardan Kulkarni ◽  
Machiraju Ramakrishna
Keyword(s):  
Catalyst Deactivation ◽  
A Priori ◽  
Coke Formation ◽  
Product Distribution ◽  
Combined Effects ◽  
Reactor Operation ◽  
Proper Selection ◽  
Pyridine Bases ◽  
Deactivation Process ◽  
Selection Of

The synthesis of pyridine bases from acetaldehyde, formaldehyde and ammonia through aminocyclization continues to provide the best prospect for meeting growing demand. A proper selection of catalyst and standardization of process parameters are vital to achieve a market friendly product distribution and reactor operation. In this work, the major responsible factors for enhancing the activity and selectivity of HZS-5 catalysts have been identified and their individual and combined effects on aldehyde conversion, coke formation and selectivity to pyridine formation have been assessed. A priori assessment of catalyst time on stream behavior has been achieved by modeling the catalyst deactivation process.

Study of coke deposition phenomena on the SAPO_34 catalyst and its effects on light olefin selectivity during the methanol to olefin reaction

RSC Advances ◽  
2015 ◽  
Vol 5 (100) ◽  
pp. 81965-81980 ◽  
Author(s):  
Reza Bagherian Rostami ◽  
Mohammad Ghavipour ◽  
Zuoxing Di ◽  
Yao Wang ◽  
Reza Mosayyebi Behbahani
Keyword(s):  
Hydrogen Transfer ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Great Influence ◽  
Product Distribution ◽  
Coke Deposition ◽  
Light Olefin ◽  
Methanol To Olefin ◽  
Olefin Selectivity ◽  
Transfer Index

Hydrogen transfer index was found to be a key parameter in prediction of coke deposition behavior. A good macro-model of product distribution with coke formation is provided. Temperature had a great influence on distribution of coke species and catalyst deactivation.

scholarly journals HDO REACTION OF THF USING Pt/γ-AL2O3 CATALYST ENRICHED BY ALUMINA : EFFECT OF TEMPERATURE TO PRODUCT DISTRIBUTION, RATE OF REACTION AND DEACTIVATON OF CATALYST

2016 ◽  
Vol 10 (1) ◽  
pp. 94
Author(s):  
Yuniawan Hidayat ◽  
Idul Fitri Nurcahyo ◽  
Ana Sofiana ◽  
Arifin Dwi Saputro
Keyword(s):  
Catalyst Deactivation ◽  
Catalyst Surface ◽  
Product Distribution ◽  
Effect Of Temperature ◽  
Exponential Regression ◽  
Rate Of Reaction ◽  
Deactivation Of Catalyst ◽  
Higher Temperature ◽  
Deactivation Process ◽  
Al2o3 Catalyst

<p>Effect of temperature variation to product distribution, rate and deactivation of catalyst of tetrahydrifuran hydrodeoxygenation have been conducted using Pt/gAl<sub>2</sub>O<sub>3</sub> with aluminum enrichmen. Reaction was conducted by flow system. Product of reaction were analyzed as propane (C<sub>3</sub>) and buthene derivate (C<sub>4</sub>). At 350ºC, reaction product and rate constant were optimum. At higher temperature, product distribution was shift from C<sub>4</sub> to C<sub>3</sub>. Lowering pore size catalyst, surface area and acidity of catalyst were responsible to catalyst deactivation. Deactivation process was follow exponential regression.</p>

scholarly journals HDO REACTION OF THF USING Pt/γ-AL2O3 CATALYST ENRICHED BY ALUMINA : EFFECT OF TEMPERATURE TO PRODUCT DISTRIBUTION, RATE OF REACTION AND DEACTIVATON OF CATALYST

2016 ◽  
Vol 10 (1) ◽  
pp. 94
Author(s):  
Yuniawan Hidayat ◽  
Idul Fitri Nurcahyo ◽  
Ana Sofiana ◽  
Arifin Dwi Saputro
Keyword(s):  
Catalyst Deactivation ◽  
Catalyst Surface ◽  
Product Distribution ◽  
Effect Of Temperature ◽  
Exponential Regression ◽  
Rate Of Reaction ◽  
Deactivation Of Catalyst ◽  
Higher Temperature ◽  
Deactivation Process ◽  
Al2o3 Catalyst

<p>Effect of temperature variation to product distribution, rate and deactivation of catalyst of tetrahydrifuran hydrodeoxygenation have been conducted using Pt/gAl<sub>2</sub>O<sub>3</sub> with aluminum enrichmen. Reaction was conducted by flow system. Product of reaction were analyzed as propane (C<sub>3</sub>) and buthene derivate (C<sub>4</sub>). At 350ºC, reaction product and rate constant were optimum. At higher temperature, product distribution was shift from C<sub>4</sub> to C<sub>3</sub>. Lowering pore size catalyst, surface area and acidity of catalyst were responsible to catalyst deactivation. Deactivation process was follow exponential regression.</p>

An analytical microscopic study of metals in fluidized catalytic cracking catalyst

1986 ◽  
Vol 44 ◽  
pp. 854-855
Author(s):  
Clifford S. Rainey
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Acid Sites ◽  
Y Zeolite ◽  
Fcc Catalyst ◽  
Fluidized Catalytic Cracking ◽  
High Regeneration

The spatial distribution of V and Ni deposited within fluidized catalytic cracking (FCC) catalyst is studied because these metals contribute to catalyst deactivation. Y zeolite in FCC microspheres are high SiO2 aluminosilicates with molecular-sized channels that contain a mixture of lanthanoids. They must withstand high regeneration temperatures and retain acid sites needed for cracking of hydrocarbons, a process essential for efficient gasoline production. Zeolite in combination with V to form vanadates, or less diffusion in the channels due to coke formation, may deactivate catalyst. Other factors such as metal "skins", microsphere sintering, and attrition may also be involved. SEM of FCC fracture surfaces, AEM of Y zeolite, and electron microscopy of this work are developed to better understand and minimize catalyst deactivation.

Innovative Approach to Information Search by Example of a Patent Analysis of an Important Substitution Plan

2020 ◽  
pp. 143-157
Author(s):  
Maria A. Milkova
Keyword(s):  
Information Search ◽  
Topic Modeling ◽  
Cognitive Biases ◽  
A Priori ◽  
Import Substitution ◽  
Innovative Approach ◽  
Iterative Search ◽  
Comprehensive Picture ◽  
Priori Information ◽  
Selection Of

Nowadays the process of information accumulation is so rapid that the concept of the usual iterative search requires revision. Being in the world of oversaturated information in order to comprehensively cover and analyze the problem under study, it is necessary to make high demands on the search methods. An innovative approach to search should flexibly take into account the large amount of already accumulated knowledge and a priori requirements for results. The results, in turn, should immediately provide a roadmap of the direction being studied with the possibility of as much detail as possible. The approach to search based on topic modeling, the so-called topic search, allows you to take into account all these requirements and thereby streamline the nature of working with information, increase the efficiency of knowledge production, avoid cognitive biases in the perception of information, which is important both on micro and macro level. In order to demonstrate an example of applying topic search, the article considers the task of analyzing an import substitution program based on patent data. The program includes plans for 22 industries and contains more than 1,500 products and technologies for the proposed import substitution. The use of patent search based on topic modeling allows to search immediately by the blocks of a priori information – terms of industrial plans for import substitution and at the output get a selection of relevant documents for each of the industries. This approach allows not only to provide a comprehensive picture of the effectiveness of the program as a whole, but also to visually obtain more detailed information about which groups of products and technologies have been patented.

Meriel Talbot and the Society for the Overseas Settlement of British Women, 1919–1937

2017 ◽  
Vol 10 (1) ◽  
pp. 32-52
Author(s):  
Bonnie White
Keyword(s):  
Domestic Service ◽  
Agricultural Workers ◽  
British Government ◽  
Early Failure ◽  
Proper Selection ◽  
Domestic Servants ◽  
Female Workers ◽  
Female Migrants ◽  
Post War ◽  
Selection Of

In 1917 the British government began making plans for post-war adjustments to the economy, which included the migration of surplus women to the dominions. The Society for the Overseas Settlement of British Women was established in 1920 to facilitate the migration of female workers to the dominions. Earlier studies have argued that overseas emigration efforts purposefully directed women into domestic service as surplus commodities, thus alleviating the female ‘surplus’ and easing economic hardships of the post-war period. This article argues that as Publicity Officer for the SOSBW, Meriel Talbot targeted women she believed would be ideal candidates for emigration, including former members of the Women's Land Army and affiliated groups. With the proper selection of female migrants, Talbot sought to expand work opportunities for women in the dominions beyond domestic service, while reducing the female surplus at home and servicing the connection between state and empire. Dominion authorities, whose demands for migrant labour vacillated between agricultural workers during the war years and domestic servants after 1920, disapproved of Talbot's efforts to migrate women for work in agriculture. Divergent policies led to the early failure of the SOSBW in 1923.

scholarly journals Incorporating radiomics into clinical trials: expert consensus on considerations for data-driven compared to biologically driven quantitative biomarkers

2021 ◽  
Author(s):  
Laure Fournier ◽  
Lena Costaridou ◽  
Luc Bidaut ◽  
Nicolas Michoux ◽  
Frederic E. Lecouvet ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Quantitative Imaging ◽  
A Priori ◽  
External Validation ◽  
Data Driven ◽  
Imaging Biomarkers ◽  
Clinical Validation ◽  
Biological Processes ◽  
Imaging Data ◽  
Selection Of

Abstract Existing quantitative imaging biomarkers (QIBs) are associated with known biological tissue characteristics and follow a well-understood path of technical, biological and clinical validation before incorporation into clinical trials. In radiomics, novel data-driven processes extract numerous visually imperceptible statistical features from the imaging data with no a priori assumptions on their correlation with biological processes. The selection of relevant features (radiomic signature) and incorporation into clinical trials therefore requires additional considerations to ensure meaningful imaging endpoints. Also, the number of radiomic features tested means that power calculations would result in sample sizes impossible to achieve within clinical trials. This article examines how the process of standardising and validating data-driven imaging biomarkers differs from those based on biological associations. Radiomic signatures are best developed initially on datasets that represent diversity of acquisition protocols as well as diversity of disease and of normal findings, rather than within clinical trials with standardised and optimised protocols as this would risk the selection of radiomic features being linked to the imaging process rather than the pathology. Normalisation through discretisation and feature harmonisation are essential pre-processing steps. Biological correlation may be performed after the technical and clinical validity of a radiomic signature is established, but is not mandatory. Feature selection may be part of discovery within a radiomics-specific trial or represent exploratory endpoints within an established trial; a previously validated radiomic signature may even be used as a primary/secondary endpoint, particularly if associations are demonstrated with specific biological processes and pathways being targeted within clinical trials. Key Points • Data-driven processes like radiomics risk false discoveries due to high-dimensionality of the dataset compared to sample size, making adequate diversity of the data, cross-validation and external validation essential to mitigate the risks of spurious associations and overfitting. • Use of radiomic signatures within clinical trials requires multistep standardisation of image acquisition, image analysis and data mining processes. • Biological correlation may be established after clinical validation but is not mandatory.

scholarly journals Design Concepts for NiTiNOL Wires to Function as a Sensor

2021 ◽  
Author(s):  
D. Josephine Selvarani Ruth
Keyword(s):  
Shape Memory Alloy ◽  
Electrical Resistance ◽  
Nickel Titanium ◽  
The Other ◽  
Sensing Element ◽  
Proper Selection ◽  
Design Concepts ◽  
Mechanical Element ◽  
Selection Of ◽  
Inverse Hysteresis

AbstractNickel Titanium Naval Ordinance Laboratory (NiTiNOL) is widely called as a shape memory alloy (SMA), a class of nonlinear smart material inherited with the functionally programmed property of varying electrical resistance during the transformation enabling to be positioned as a sensing element. The major challenge to instrument the SMA wires is to suppress the wires’ nonlinearity by proper selection of two important factors. The first factor is influenced by the mechanical biasing element and the other is to identify the sensing current for the sensing device (SMA wires + biasing). This paper focuses on developing SMA wires for sensing in different orientation types and configurations by removing the non-linearity in the system’s output by introducing inverse hysteresis to the wires through the passive mechanical element.

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