PROMISING TECHNOLOGIES AND EXISTING EXPERIENCE OF CARBON DIOXIDE EXTRACTION FROM PROCESS AND WASTE GASES

Abstract

The main technologies for carbon dioxide capturing are analyzed. Promising technologies include “before burning” CO2 capture and CO2 injection into depleted oil fields to enhance oil recovery, which make it possible not only to reduce residual oil saturation, but also to reduce carbon dioxide emissions into the atmosphere effectively. The energy costs of amine processes for extracting carbon dioxide from biogas are analyzed with the use of computer simulation. To extract carbon dioxide from process gases a traditional single-flow absorption scheme can be used in which MDEAmod absorbents the optimal in terms of energy performance minimizing. The MDEAmod absorbent is universal and can be used in CO2 extraction processes, including those under high pressure, from various process gases, in which the CO2 content can vary over a wide range of concentrations and reach 45 % (vol.). The use of this absorbent reduces the heat consumption for the regeneration of the saturated sorbent by 1.4–2.5 times compared to 18 % MEA and reduces the absorbent consumption by 30 %. A laboratory unit for extracting target fractions of biomethane and carbon dioxide from biogas has been created. The model calculation results of the amine CO2 extracting from biogas and those obtained on a laboratory unit are quite close and the deviation of the calculated from the experimentally obtained CH4 concentration in biomethane at a pressure in the absorber Pabs = 0.11–0.2 MPa does not exceed 3 %. The results of extracting carbon dioxide from biogas modeling can be used to optimize the technological absorption schemes for the production of biomethane - an analogue of natural gas. Experimental technology has been developed and equipment for the production and decomposition of natural gas and carbon dioxide hydrates has been created. The thermodynamic parameters of hydrate formation by bubbling have been determined, and hydrate samples have been obtained. Thermodynamic trend of pressure difference of 1.5–2 MPa to methane replace with carbon dioxide in hydrates was experimentally established and thus the possibility of replacing methane gas hydrates with carbon dioxide and using this technology for the conditions of developing gas hydrate deposits in the Black Sea was confirmed. Bibl. 30, Fig. 10, Tab. 3.