Flow characteristics of systems for carbon dioxide scrubbing from the atmosphere in the pressurized volume of a space station

Abstract

Carbon dioxide (СО2) scrubbing from pressurized volumes of long-term space stations is one of the most critical aspects of crew life support, since each person, on average, releases 480 liters of СО2 (~ 1kg) per day. Meanwhile, СО2 is one of the gases required for human breathing, but at the same time its content in the atmosphere of the pressurized cabin must be kept below established standards, exceedance of which makes СО2 a contaminant harmful to humans. It should also be taken into account that at present the established standards for СО2 content in the space station atmosphere are not based on scientific research. The key parameter of the scrubbing system, which determines the СО2 content in the atmosphere of the space station pressurized cabin, is the effective flow rate of the scrubbed air through the system. It was established that in order to scrub the atmosphere, two requirements must be met: 1) supply the required air flow rate to the scrubbing system (this requirement applies to all types of the system), 2) provide the required efficiency of the scrubbing system for the contaminant removal. A formula has been derived for calculating the effective flow rate through the air scrubbing system, allowing not only to calculate the necessary charge through system of clearing, but also which makes it possible to compare performances of various types of systems. It was established that the most efficient system for scrubbing СО2 from the air is the sorption system, since it has the largest absorption surface, all other conditions being equal, and, therefore, it has the highest efficiency factor Key words Space station, carbon dioxide, air scrubbing, standards for СО2 content, effective airflow rate, calculation formula, efficiency factor, absorption system for scrubbing СО2 from air.