Figure 1: The effect of pressure on the amount of carbon dioxide absorption at 313 K and at 1M piperazine concentration in comparison with literature data (Chung et al. 2010).
Figure 1 shows the effect of pressure on the amount of carbon dioxide absorption at 333 K and at 1M piperazine concentration. As seen in the figure, carbon dioxide absorption increases with increasing pressure. The reason for this is that, at higher pressures of the gradient, carbon dioxide concentrations in the gas phase increase, and this increase in concentration increases the chemical potential of the mass transfer from gas to the liquid solution, and the absorption efficiency improves in the gas absorption process, resulting in high pressure Increased absorption potential improves separation (steep slope of the graph). But at high pressures, this increase in pressure increases the flow rate of gas passing through the tower, which reduces the time remaining and does not allow sufficient time to transfer carbon dioxide from the gas phase to the soluble phase. So in this case, the carbon dioxide absorption rate (curve slope) is lower than the lower pressures.
Figure 2 depicts the carbon dioxide absorption in the system in terms of pressure variations at various operating temperatures at a concentration of 1M of piperazine and a temperature of 333 K.
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