A way of the Working Process Organization in Case of the Long-Term Operation of Power Plants with Aluminum Fuel for the Aerospace Industry

Аuthors

Okorokova N. S.^*, Pushkin K. V.^**, Sevruk S. D.^***, Suvorova E. V.^****, Farmakovskaya A. A.^*****

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

*e-mail: ok.nadezhda@mail.ru
**e-mail: konstantin-val@yandex.ru
***e-mail: sds46@yandex.ru
****e-mail: lelya-suvorova@yandex.ru
*****e-mail: a.a.farmakovskaya@gmail.com

Abstract

Aluminum based chemical power plants use oxygen as an oxidizer, and that is why they are called as the aluminium-air power plants (AA PP). An AA PP is an energy efficient one among the currently known chemical current sources (CCS) in consequence of the high density of energy output (720-2340 kJ/kg or 250-700 Wh/kg), and it trails only the oxygen-hydrogen (О₂/Н₂) fuel cells (FC) with cryogenic storage system and some CCS with the lithium anode.
Based on the AA CCS study fulfilled by us it is possible to create power plants for different applications with a wide range of power output — from several watts to some tens of kilowatts. The construction arrangement of such power plants will obviously be substantially different — it depends on the power, the type of electrolyte and the design map of a power plant.
This paper presents the processes occurring in the AA CCS and AA power plants and the basic diagrams of AA PP designed for different purposes; besides, we offer main requirements to the auxiliary and service systems of such power plants.
The novel solutions for the main units of AA power plants are offered in this paper. We examine also the important process of the electrolyte clarification from the reaction products. This process is one of the limited processes in the CCS, which influences the working life and energy output of the AA CCS.
However, the operating time and the life cycle of the AA power plant are limited by the anode passivation and the destruction of the gas-diffusion cathode, which are the consequences of the reaction products (namely: aluminates and solid hydroxides). These characteristics can be improved by organizing the electrolyte cleaning system.
For increasing the AA PP operating time, we examined several ways of organizing the electrolyte cleaning system. Such ways are associated with a periodic or constant process of decomposition of the oversaturated aluminate solutions. They are associated also with a presence or lack of any crystallized component in the cells and the possibility to combine this component with the assembly of electrolyte cleaning system.
Parameters of the electrolytic circulating contour were assessed. That assessment showed that at the high decomposition rate (which conforms to the high concentration of the dissolved aluminum — the saturation rate is 1.5 and higher), the process of the crystallization proceeds in the electrolytic circulating contour.
This paper shows that sometimes for intensifying the process of electrolyte cleaning it will be required to use some special arrangement — crystallizer. The desired seed concentration in the crystallizer will be organized. The application conditions of the PP determine the optimal construction and the working diagram of the crystallizer. It is also shown that it is possible to use three types of units for cleaning the electrolyte from solid phase: sumps, filters and centrifugal separating devices.

Keywords:

aluminium, anode, air, corrosion, organic inhibitor, polarization, electrochemical cell, electrolyte, electric power plant

References

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