The effect of the complex processing of Microalgae Chlorella vulgaris on the intensification of the lipid extraction process

Microalgae are considered a promising source of lipids. However, the existing technologies of their extraction necessitate a massive improvement. In the course of the study optimal parameters of microwave radiation and of enzyme mixture "Cellolux A" and "Protosubtilin G3x" were experimentally selected and theoretically proved so as to allow increasing the yield of lipids 5.75 times to 23 % in comparison with the control sample (5 %). Moreover, the ratio and type of polar and non-polar solvents in the extraction stage for the maximum extraction of lipids was determined taking into account the necessity to process protein-lipid complexes

Numerical study of the dynamics of synthesis gas adsorption separation

A numerical study of the dynamics of pressure swing adsorption process for synthesis gas separation and hydrogen concentration was carried out. The influence of regime parameters (compressor and vacuum pump outlet pressures, duration of the "adsorption-desorption" cycle, backflow coefficient) and design parameters (height of the adsorbent bulk layer and the internal bed diameter) on the recovery and purity of hydrogen, plant performance in a given range of changes in the temperature, composition and pressure of the initial gas mixture was studied. It is found that when the hydrogen content decreases from 68 to 48 vol. % and a simultaneous increase in the carbon dioxide content in the initial gas mixture from 27 to 47 vol. % required hydrogen purity value at 99.99 vol. % can be achieved by reducing the pressure at the outlet of the vacuum pump from 0.75?105 to 0.5?105 Pa. At the same time, the duration of the adsorption stage increases from 120 to 150 seconds, and the degree of hydrogen extraction decreases from 55 to 52% due to an increase in the proportion of the flow selected for the regeneration of the adsorbent. Increasing the temperature of the initial gas mixture from 293 to 323 K leads to the need to reduce the duration of the adsorption stage from 148 to 42 s due to a decrease in the equilibrium concentrations of carbon dioxide and monoxide in the adsorbent

Numerical Study of the Dynamics of Air Separation Process by Pressure Swing Adsorption

Using mathematical modelling and the finite element method, we carry out the calculation experiments to study the system connections and regularities of pressure swing adsorption process under the conditions of air separation and oxygen concentration (production). We study the influence of mode and construction variables on the dynamics and technological indicators of the effectiveness of this process. Namely, we study the influence of input variables (composition and temperature of atmospheric air, air pressure at the compressor outlet) on output variables (extraction degree, oxygen purity, unit capacity, etc.) of the studied object in a wide range of control variables (adsorption-desorption cycle time, pressure ratios at adsorption and desorption stages, and oxygen-enriched reverse air flow coefficient). Also, we study the influence of construction parameters (layer height, particle diameter and maximum adsorption volume of the adsorbent) on the amount of adsorption, which is equilibrium with the current concentration of the adsorptive in the gas mixture flow on the outer surface of the adsorbent granules, the value of the kinetic adsorption coefficient (the coefficient of external mass transfer of the adsorptive (mainly nitrogen) from the gas phase into the adsorbent). The results of calculation experiments allow to establish the most promising mode and construction parameters for the optimal design of oxygen enrichment systems by pressure swing adsorption with varying pressure.С использованием математического моделирования и метода конечных элементов проведены вычислительные эксперименты по исследованию системных связей и закономерностей процесса короткоцикловой безнагревной адсорбции при разделении воздуха и концентрирования (получения) кислорода. Проведено изучение влияния режимных и конструктивных переменных на динамику и технологические показатели эффективности данного процесса, а именно: 1) входных переменных (состава и температуры атмосферного воздуха, давления воздуха на выходе компрессора) на выходные переменные (степень извлечения, чистоту кислорода, производительность установки и т.п.) объекта исследования в широком диапазоне варьирования управляющих переменных (длительности цикла адсорбция-десорбция, отношения давлений на стадиях адсорбции и десорбции и коэффициента обратного потока воздуха, обогащенного кислородом); 2) конструктивных параметров (высоты слоя, диаметра частиц и предельного адсорбционного объема адсорбента) на величину адсорбции, равновесной текущей концентрации адсорбтива в потоке газовой смеси на внешней поверхности гранул адсорбента, значение кинетического коэффициента адсорбции (коэффициента внешней массоотдачи адсорбтива (преимущественно азота) из газовой фазы в адсорбент). В ходе анализа результатов вычислительных экспериментов установлены наиболее перспективные режимные и конструктивные параметры для оптимального проектирования установок обогащения воздуха кислородом методом короткоцикловой адсорбции с изменяющимся давлением

Problems of analysis, optimization and control in the separation of gas mixtures

Mathematical models of dynamics of pressure swing adsorption processes for the separation of synthesis gas (into hydrogen, carbon dioxide and carbon monoxide) and air (into oxygen, nitrogen and argon) have been developed. The models allow calculating the profiles of component concentrations and temperature of gas and solid phases, pressure and velocity of gas mixture along the height of adsorbent in relation to time. The models include the following equations: 1) processes of mass and heat transfer during the adsorption (desorption) of a sorptive (H2, CO2, COandO2, N2, Ar) by granulated zeolite adsorbents 5Aand13Х; 2) kinetics of compound diffusion transport of adsorbate and Langmuir-Freundlich isotherm (for the synthesis gas separation), kinetics of external diffusion and Dubinin-Radushkevich isotherm (for the air separation); 3) the Ergun equation for the calculation of pressure and velocity of gas mixture in adsorbent.The system of partial differential equations was solved by method of lines. The system of ordinary differential equations was solved by the fourth-order Runge-Kutta method with automatic step selection.To analyze the accuracy of mathematical models of the adsorption separation of synthesis-gas for recovery hydrogen, the relative error of the mismatch between the calculated values for the model and the experimental values of the concentration of the product (hydrogen, oxygen) in the 'steady state' (after 15-30 operating cycles of the PSA) was calculated. The maximum value of the relative error did not exceed 11.5%.Numerical studies were carried out in a wide range of changes in the time of the cycle "adsorption-desorption" and the pressure at the stage of adsorption to determine the effect of changes in temperature, composition and pressure of the initial gas mixture on the purity, recovery and temperature of production hydrogen and oxygen, as well as the relationship of the PSA unit capacity with the purity of the resulting product (hydrogen, oxygen). The problem of adaptive optimization of the process of adsorption separation of a gas mixture and obtaining hydrogen and oxygen with a maximum concentration was formulated and solved.The algorithmic and software of the automated adaptive control system was developed

Numerical study of the dynamics and optimization of the modes of air adsorption separation and oxygen concentration

Numerical researches of influence of temperature, composition and pressure changes of the initial gas mixture on the purity, recovery and capacity of the pressure swing adsorption (PSA) unit was made. Air separation dynamics was researches in a wide range of control (pressure at the compressor outlet, the duration of the adsorption – desorption cycle, backflow coefficient, programs of control valves opening degree in time) variables. It was found that the change of regime parameters and the inflow on has a significant impact on the purity and recovery of oxygen. Also was founded that the range of the duration of the adsorption stage and the compressor outlet pressure values should be limited to the intervals of 39-43 s and 2.7–2.8?105 Pa, respectively. The steady-state of the PSA unit mode output time was amount 20-30 cycles of "adsorption-desorption". Formulated and solved the optimization tasks of regime parameters of air separation cyclic processes by criterion of maximum oxygen recovery in 2-bed PSA unit with granular adsorbent zeolite 13X; the optimal values of the control parameters for differential environmental conditions (when the product oxygen concentration not less than 45% vol. and the PSA unit capacity ~2 l/min) are determined. It is shown that the implementation of the optimal of the inlet and discharge valves opening degree changes program in PSA unit allows to provide the set values of the gas flow rate in the "frontal" layer of the adsorbent, in which there is no abrasion of the adsorbent in the cyclic adsorption–desorption processe