A mathematical model of the dynamics of pressure swing adsorption (PSA) process during separating multicomponent gas mixtures to produce hydrogen has been developed. The model includes the equations of mass-and heat transfer processes which occur during adsorption (desorption) of the components (H 2 , CO 2 и CO) of gas mixture by granular zeolite adsorbents СаА, NaХ, LiLSX; the equation of the kinetics of mixed-diffusive transport of adsorbate (H 2 , CO 2 и CO); the LangmuirFreundlich isotherm equation for multicomponent gas mixtures; the Ergun equation for calculating the pressure and velocity of gas mixture in the adsorber, and allows calculating the profiles of component concentrations (H 2 , CO 2 и CO) and temperature in the gas and solid phases, pressure and velocity of the gas mixture along the height of the adsorbent depending on time. As a result of computational experiments, the effect of changes in the temperature, composition, and pressure of the initial gas mixture on the purity, recovery, and production hydrogen temperature at multiple duration periods of the adsorption stage was determined. The dynamics of the adsorption process of gas mixture components and the character of sorption and thermal fronts motion along the height of the adsorbent bed in the adsorber, as well as the relationship between the output of the 4-column PSA unit and the purity of the produced hydrogen have been studied.
There was executed the assessment of carcinogen and non-carcinogen risks for population health in some areas of the western, south-western and south-eastern administrative districts of Moscow under the exposure to air borne contaminants whose levels are kept track by various government agencies as part of the socio-hygienic monitoring. The value of chronic non-carcinogenic risks to the health of the population as measured according to the danger index for the combined impact of average annual concentrations of leading air borne contaminants with unidirectional impacts are at near alarming or high level depending on the location of monitoring outposts while for on-off short term exposure to maximum concentrations the impacts are at alarming or acceptable level. The highest danger indices were detected at outposts located near major motorways and industrial facilities. According to monitoring data collected by all agencies the air borne contaminants pose the highest risk to the respiratory organs due to exposure to formaldehyde, air-borne particles and nitrogen dioxide. The extra deaths resulting from chronic exposure to РМ10, estimated by the Moscow Environmental Monitoring make up about 1% of the total mortality rate without bearing in mind of external causes for the population residing in the western, south western and south eastern administrative districts. The total individual carcinogenic risks resulting from the exposure to average annual concentration of a number of carcinogens was found to be between the acceptable and alarming levels. The leading compound contributing to the increased carcinogenic risk is formaldehyde.
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