COMPARATIVE ANALYSIS OF THE EFFICIENCY OF WATER AND WATER-AMINE ABSORPTION PROCESSES FOR EXTRACTING CO2 FROM BIOGAS

The production of biomethane from biogas energy costsfor the most widely used amine and water processes for extracting carbon dioxide from biogas were analyzed using computer simulation. Combined water-amine absorption method of biogas purification from CO2 wasincluded in the comparative analysis. For the CO2 content of the biogas from 32 to 42 %, the specific energy costs when using water absorption to extract carbon dioxide from biogas are, on average, in ~ 2.5 times lower than amine absorption, but the loss of CH4 by water absorption was 7.1–7.6 % due to its watersolubility with practically zero CH4 loss when using amine absorption and insignificant loss (0.17–2.8 %) using water-amine technology. Using preliminary water absorption of CO2 saved CH4 can compensate the power consumption of the biogas compressor or the heatcosts of saturated amine absorbent regenerating. This will allowto reduce energy consumption to almost equal to water absorptionone. The results of simulation of carbon dioxide extraction from biogas can be used to optimize technological absorption schemes for the production of biomethane — an analogueof natural gas. Bibl. 13, Fig. 5, Tab. 6.

Nitrosamines and nitramines in Carbon Capture plants

The use of amine absorption in carbon capture technologies is related with the formation toxic and potentially carcinogenic amine degradation products such as nitrosamines and nitramines. These substances can be created within both the solvent and the atmosphere when air components (mainly NOx) and amines react with each other. These substances may pose environmental and health risks depending on the level and duration of the exposure. In this paper, formation and occurrence of nitrosamines and nitramines in carbon capture plants were described. Emission reducing technologies have been also mentioned. Furthermore, an overview of experimental data of emission of nitrosamines and other major degradation products has been pointed out.

Molecular dynamic simulation of CO2 absorption into mixed aqueous solutions MDEA/PZ

<p>The mixture of amine absorption process is an approach for mitigation of carbon dioxide (CO₂) from flue gas that produces from power plant. Several experimental and simulation studies have been undertaken to understand this process but the mechanism of CO₂ absorption into the aqueous blended amines such as MDEA/PZ is not well understood and available knowledge within the open literature is limited. The aim of this study is to investigate the intermolecular interaction of the blended MDEA/PZ using Molecular Dynamics (MD) simulation. MD simulation was run under condition 313 K and 1 atm. The thermodynamic ensemble used were 200 ps for NVE and 1 ns for NVT. The periodic boundary is used to visualize the interaction of molecules of the whole system. The simulation method also involved calculation of force field and time integration algorithm.The results were interpreted in terms of Radial Distribution Function (RDF) analysis. It was observed that the hydroxyl group (–OH) of MDEA is more attracted to water molecule compared to amino group (–NH) of MDEA. The intermolecular interaction probability of –OH and –NH group of MDEA with CO₂ in blended MDEA/PZ is higher than using pure MDEA. This finding shows that PZ molecule act as an activator to promote the intermolecular interaction between MDEA and CO₂.Thus, blend of MDEA with PZ is expecting to increase the absorption rate of CO2 and reduce the heat regeneration requirement.</p><p>Chemical Engineering Research Bulletin 19(2017) 1-11</p>