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Domieszkowane katalizatory kobaltowo-molibdenowe do syntezy amoniaku

Nadziejko Marlena, Adamski Paweł, Moszyński Dariusz

Przemysł Chemiczny

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2020

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T. 99, nr 10

1454--1458

PL

Zbadano katalizatory kobaltowo-molibdenowe stanowiące alternatywę dla katalizatorów żelazowych do syntezy amoniaku. Określono wpływ stężenia związków cezu, chromu oraz potasu, zastosowanych jako promotory, na zawartość faz krystalicznych azotków kobaltu i molibdenu (Co₂Mo₃N i Co₃Mo₃N) w katalizatorach przed i po procesie syntezy amoniaku. Ustalono także wpływ stężenia promotorów na takie właściwości katalizatorów, jak aktywność katalityczna i wielkość powierzchni.

EN

The Co-Mo oxide catalyst was modified with Ce, Cr and K ions by an impregnation method and treated with NH₃ at 700°C for 5 h. The contents of promoters, phase compn. and sp. surface of catalyst were detd. The catalyst were used for NH₃ synthesis at 400°C and 10 MPa and then subjected to aging at 650°C for 12 h in order to assess their thermal stability. The effect of promoter concn. on the activity, sp. surface and content of cryst. phases of Co₂ Mo₃N and Co₃Mo₃N were detd.

2

The Computational Power of Cell-like P Systems with Symport/Antiport Rules and Promoters

Jiang Suxia, Wang Yanfeng, Xu Jinbang, Xu Fei

Fundamenta Informaticae

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2019

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Vol. 164, nr 2-3

207--225

EN

Cell-like P systems with symport/antiport rules (CSA P systems, for short) are a class of computational models in membrane computing, inspired by the way of transmembrane transport of substances through membrane channels between neighboring regions in a cell. In this work, we propose a variant of CSA P systems, called cell-like P systems with symport/antiport rules and promoters (CSAp P systems, for short), where symport/antiport rules are regulated by multisets of promoters. The computational power of CSAp P systems is investigated. Specifically, it is proved that CSAp P systems working in the maximally parallel mode, having arbitrary large number of membranes and promoters and using only symport rules of length 1 or antiport rules of length 2, are able to compute only finite sets of non-negative integers. Furthermore, we show that CSAp P systems with two membranes working in a sequential mode when having at most two promoters and using only symport rules of length 2, or having at most one promoter and using symport rules of length 1 and antiport rules of length 2, are Turing universal.

3

Properties and activity of the cobalt catalysts for NH3 &enspsynthesis obtained by co-precipitation – the effect of lanthanum addition

Zybert M., Karasińska M., Truszkiewicz E., Mierzwa B., Raróg-Pilecka W.

Polish Journal of Chemical Technology

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2015

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Vol. 17, nr 1

138--143

EN

In modern research on catalysts for NH3&enspsynthesis a lot of attention is paid to cobalt. In this work the new catalytic systems based on cobalt are presented. Unsupported cobalt catalysts singly promoted (La or Ba) and doubly promoted (La and Ba) were prepared and tested in NH3&enspsynthesis reaction under commercial synthesis conditions. Characterization studies revealed that lanthanum plays a role of a structural promoter, which improves the surface of catalyst precursors and prevents from sintering during calcination. However, lanthanum has a negative effect on the reduction of cobalt oxide, but the addition of barium promoter (Co/La/Ba catalyst) diminishes the negative impact of La. The co-promotion of cobalt with lanthanum and barium results in the increasing of the active phase surface and improvement of its activity in NH3&enspsynthesis.

4

Membrane Systems with Qualitative Evolution Rules

Kleijn J., Koutny M.

Fundamenta Informaticae

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2011

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Vol. 110, nr 1-4

217-230

EN

In membrane systems, biochemical reactions taking place in the compartments of a cell are abstracted to evolution rules that specify which and how many objects are consumed and produced. The recently proposed reaction systems also investigate processes carried by biochemical reactions, but the resulting computational model is remarkably different. A key difference is that in reaction systems, biochemical reactions are modeled using a qualitative rather than a quantitative approach. In this paper, we introduce so-called set membrane systems, a variant of membrane systems with qualitative evolution rules inspired by reaction systems. We then relate set membrane systems to Petri nets which leads to a new class of Petri nets: set-nets with localities. This Petri net model provides a faithful match with the operational semantics of set membrane systems.