The paper deals with the computational fluid dynamics modelling of carbon dioxide capture from flue gases in the post combustioncapture method, one of the available carbon capture and storage technologies. 30% aqueous monoethanolamine solution was used as a solvent in absorption process. The complex flow system including multiphase countercurrent streams with chemical reaction and heat transfer was considered to resolve the CO2 absorption. The simulation results have shown the realistic behaviour and good consistency with experimental data. The model was employed to analyse the influence of liquid to gas ratio on CO2 capture efficiency.
The installations of CO2 capture from flue gases using chemical absorption require a supply of large amounts of heat into the system. The most common heating medium is steam extracted from the cycle, which results in a decrease in the power unit efficiency. The use of heat needed for the desorption process from another source could be an option for this configuration. The paper presents an application of gas-air systems for the generation of extra amounts of energy and heat. Gas-air systems, referred to as the air bottoming cycle (ABC), are composed of a gas turbine powered by natural gas, air compressor and air turbine coupled to the system by means of a heat exchanger. Example configurations of gas-air systems are presented. The efficiency and power values, as well as heat fluxes of the systems under consideration are determined. For comparison purposes, the results of modelling a system consisting of a gas turbine and a regenerative exchanger are presented.
The paper deals with numerical modelling of carbon dioxide capture by amine solvent from flue gases in post-combustion technology. A complex flow system including a countercurrent two-phase flow in a porous region, chemical reaction and heat transfer is considered to resolve CO2 absorption. In order to approach the hydrodynamics of the process a two-fluid Eulerian model was applied. At the present stage of model development only the first part of the cycle, i.e. CO2 absorption was included. A series of parametric simulations has shown that carbon dioxide capture efficiency is mostly influenced by the ratio of liquid (aqueous amine solution) to gas (flue gases) mass fluxes. Good consistency of numerical results with experimental data acquired at a small-scale laboratory CO2 capture installation (at the Institute for Chemical Processing of Coal, Zabrze, Poland) has proved the reliability of the model.
The surface properties of particles emitted from six selected coal-fired power and heating plants in Poland have been studied in this work for the first time. Samples were collected beyond the control systems. Surface composition of the size-distributed particles was obtained by photoelectron spectroscopy (XPS). The reflection of the smallest, submicron particles was also measured to calculate their specific/mass absorption. The surface layer of the emitted particles was clearly dominated by oxygen, followed by silicon and carbon. The sum of the relative concentration of these elements was between 85.1% and 91.1% for coarse particles and 71.8–93.4% for fine/submicron particles. Aluminum was typically the fourth or fifth, or at least the sixth most common element. The mass absorption of the submicron particles emitted from the studied plants ranged from 0.02 m2g-1 to 0.03 m2g-1. Only specific absorption obtained for the “Nowy Wirek” heating plant was significantly higher than in other studied plants probably because the obsolete fire grate is used in this heating plant. The obtained results suggest that the power/heating-plant-emitted fine particles contain less carbonaceous material/elemental carbon on their surfaces than those that are typical in urban air.