Optimal start-up strategies of a combined cooling and antisolvent multistage continuous crystallization process

Author(s):  
Jiaxu Liu ◽  
Brahim Benyahia
2014 ◽  
Vol 672-674 ◽  
pp. 769-772
Author(s):  
Wei Wei Li ◽  
Qiang Shi ◽  
Chi Wu

The effect of electrical aging on the trap parameter of HVAC XLPE cable insulation was investigated in this work. Thermally Stimulated Current (TSC) was used to measure depolarization current. The variation of trap parameter was calculated by means of start-up method based on the Gaussian fitting curve of TSC data. It was found that, the activation energy and the amount of trap charge obtained from TSC peak at 243K and 348K were increased after electrical aging, which may be benefit to characterize the degree of aging. The amount of trap charge in the two peaks increases as the increase of oxide dipole after electrical aging. And charge trapped described by the TSC peak at melting temperature increased after aging. It is considered that the increase of charge in the TSC peak can be attributed to the release of trap charge in the melt crystallization process, which corresponds to the α relaxation process in XLPE insulation.


Author(s):  
Christof Weinlaender ◽  
Johannes Albert ◽  
Christian Gaber ◽  
Martin Hauth ◽  
René Rieberer ◽  
...  

This paper presents the development of the subsystems for stationary biogas powered solid oxide fuel cell (SOFC)-based combined cooling, heat and power (CCHP). For certain applications, such as buildings, a heat-driven operation mode leads to low operating hours per year for conventional combined heat and power (CHP) systems due to the low heat demand during the summer season. The objectives of this study are the evaluation of an adsorber, a steam reformer, a SOFC, and an absorption chiller (AC). Biogas, however, contains impurities in the form of hydrogen sulfide (H2S), hydrogen chloride (HCl), and siloxanes in different concentrations, which have a negative effect on the performance and durability of the SOFC and, in the case of H2S, also on the catalyst of the steam reformer. This paper describes different experimental sections: (i) the biogas treatment with its main focus on H2S separation and steam reforming, (ii) the setup and start-up of a 10 cell SOFC stack, and (iii) test runs with an AC using a mixture of NH3 (ammonia)/H2O (water). The components required for the engineering process of the subsystem's structure are described in detail and possible options for system design are explained. The evaluation is the basis to reveal the improvement potentials, which have to be considered in future product developments. This paper aims at comparing experimental data of the test rigs to develop an understanding of the requirements for a stable and continuous operation of a SOFC-based CCHP operated by biogas.


Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1337
Author(s):  
Michael Mangold ◽  
Nadiia Huskova ◽  
Jonathan Gänsch ◽  
Andreas Seidel-Morgenstern

Continuous preferential crystallization is an innovative approach to the separation of chiral substances. The process considered in this work takes place in a gently agitated fluidized bed located in a tubular crystallizer. The feasibility of the process has been shown in previous work, but it also turned out that choosing suitable operation conditions is quite delicate. Hence, a model based process design is desirable. Existing models of the process are rather complicated and require long computational times. In this work, a simple linear dynamic model is suggested, which captures the main properties of the process. The model is distributed in space and in a property coordinate. Using the method of characteristics, a semi-analytical solution of the linear model is derived. As a challenge to the solution, there is a recycle loop in the process that causes a feedback and couples the boundary conditions at different boundaries of the computational domain. In order to deal with this, a numerical scheme is suggested. The semi-analytical solution provides a deeper insight into the process dynamics. A comparison with a more detailed mathematical model of the process and with experiments shows strengths and limitations of the linear model.


2016 ◽  
Vol 88 (9) ◽  
pp. 1213-1213 ◽  
Author(s):  
M. Escriba-Gelonch ◽  
V. Hessel ◽  
T. Noël ◽  
M. C. Maier ◽  
H. Gruber-Wölfler

AIChE Journal ◽  
1996 ◽  
Vol 42 (3) ◽  
pp. 767-776 ◽  
Author(s):  
R. A. Eek ◽  
J. A. Both ◽  
P. M. J. Van den Hof

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