Influence Of CO2 Content Research Articles

Experiments on the Rock Electricity and Application Research considering the Influence of CO2 Content: A Case Study of the Dongfang 13 Gas Field

Abstract A large number of CO2-bearing gas layers are distributed in the deep layers in the Huangliu and Meishan formations of the Dongfang 13 gas field. The presence of CH4, CO2, and formation water in CO2-bearing gas layers complicates the change of logging response characteristics. In particular, the unclear understanding of the additional conductivity change law formed by the coupling of CO2 and formation water results in low accuracy of the water saturation results, and the aforementioned type of gas layer can easily be misidentified as the gas-water mixed layer. By conducting multiple rock electrical experiments under simulated formation temperature and pressure conditions, core flooding experiments were conducted with different contents of CO2 and CH4 mixed gas to determine the lithology coefficient b, saturation coefficient n, and cementation coefficient m of cores under different experimental conditions. Additionally, we also analyzed the relationship between the electrical parameters of rocks, CO2 content, and water saturation to reveal the influence of coupling of CO2 and formation water on the change of electrical parameters of rocks under high temperature and pressure conditions. The experimental results show that when the mixed gas with different CO2 contents is dissolved in the formation water, there is no difference between the measured lithology coefficient a and the cementation coefficient m; as the CO2 content increases, the lithology coefficient b increases, and the saturation coefficient n decreases. Based on the experimental results, we established a prediction model of the change between lithology coefficient b, saturation coefficient n, and CO2 content. This model improves the accuracy of water saturation calculations in the CO2-bearing gas layers along with that of fluid identification.

Simulation of intensified process of sorption enhanced chemical-looping reforming of methane: Comparison with conventional processes

Intensified process of sorption enhanced chemical-looping reforming (SECLR) for hydrogen production was studied. This process was modified by recycling a portion of solid NiO and CaO from air reactor (AR) to reforming reactor (RR) and employing the exhaust CO2 as sweep gas at the calcination reactor (CR) under energy self-sufficient operation. By comparing the process performances among SECLR, conventional steam reforming (SR) and sorption enhanced steam reforming (SESR) at their optimum conditions, the intensified SECLR under adiabatic operation showed the best performance with hydrogen productivity of 3.95kmol/h, CH4 conversion of 98% and H2 purity of 98.37%. Additionally, the optimized SECLR process operated adiabatically required the solid ratio from CR to AR of 0.945 and solid ratio from AR to RR of 0.008, leading to the minimum of heat requirement. Furthermore, the influence of CO2 content in feed stream on adiabatic operation of the SECLR process was investigated.

Enhanced oxygen separation through robust freeze-cast bilayered dual-phase membranes.

Dual-phase oxygen-permeable asymmetric membranes with enhanced oxygen permeation were prepared by combining freeze-casting, screen-printing, and constraint-sintering techniques. The membranes were evaluated under oxyfuel operating conditions. The prepared membranes are composed of an original ice-templated La(0.6)Sr(0.4)Co(0.2)Fe(0.8)O(3-δ) support with hierarchically oriented porosity and a top fully densified bilayered coating comprising a 10 μm-thick La(0.6)Sr(0.4)Co(0.2)Fe(0.8)O(3-δ) layer and a top protective 8 μm-thick layer made of an optimized NiFe2O4/Ce(0.8)Tb(0.2)O(2-δ) composite synthesized by the one-pot Pechini method. Preliminary analysis confirmed the thermochemical compatibility of the three involved phases at high temperature without any additional phase detected. This membrane exhibited a promising oxygen permeation value of 4.8 mL min(-1) cm(-2) at 1000 °C upon using Ar and air as the sweep and feed gases, respectively. Mimicking oxyfuel operating conditions by switching argon to pure CO2 as a sweep gas at 1000 °C and air as feed enabled an oxygen flux value of 5.6 mL min(-1) cm(-2) to be reached. Finally, under the same conditions and increasing the oxygen partial pressure to 0.1 MPa in the feed, the oxygen permeation reached 12 mL min(-1) cm(-2). The influence of CO2 content in the sweep gas was studied and its reversible and positive effect over oxygen permeation at temperatures equal to or above 950 °C was revealed. Finally, the membrane stability over a period of 150 h under CO2-rich sweep gas showed a low degradation rate of 2.4×10(-2) mL min(-1) cm(-2) per day.

Effects of Nanoclay and CO<sub>2 </sub>Content on Foaming Behaviors of PP/PS Alloys

Microcellular foaming behavior of polypropylene/polystyrene (PP/PS) composites with or without the addition of nanoclay was compared in an extrusion foaming process by using supercritical CO2 as the foaming agent. The influence of CO2 content on foaming of the composites was investigated in the study. Our experiment results demonstrated that the introduction of nanoclay dramatically improved the foaming of the PP/PS blends with increased cell-population density and decreased cell size. With the increase of CO2 injected in the foaming process, cell-population density of the foam samples further increased.

Influence of CO2 co-feeding on Fischer–Tropsch fuels production over carbon nanofibers supported cobalt catalyst

Nowadays, the syngas which is obtained from the reforming of coal, biomass or natural gas contain significantly amounts of CO2 that cannot be separated and consequently, it can take part into the Fischer–Tropsch (FTS) catalytic activity. Therefore, the presence of CO2 in the syngas flow should be taken into account. In the present study, the FTS CO hydrogenation process was compared to that of CO2 on a carbon nanofibers supported Co catalyst. The influence of CO2 content in the feed stream (H2/CO/CO2 ratio) on the reaction performance in terms of conversion and selectivity to the different products was described. Both the support and the prepared catalyst were characterized by nitrogen adsorption–desorption, temperature-programmed reduction (TPR) and X-ray diffraction (XRD). Results showed that CO hydrogenation was controlled by a Fischer–Tropsch regime, whereas CO2 hydrogenation was controlled by a methanation process. When feed was composed of CO and CO2 mixtures, the catalytic activity decreased with respect to that obtained with a CO2-free feed stream. Moreover, the presence of CO2 in feed stream favored the formation of lighter hydrocarbons and could block the production of further CO2 via Water-Gas-Shift (WGS) reaction.

Influence of SO2 in incineration flue gas on the sequestration of CO2 by municipal solid waste incinerator fly ash

The influence of CO2 content and presence of SO2 on the sequestration of CO2 by municipal solid waste incinerator (MSWI) fly ash was studied by investigating the carbonation reaction of MSWI fly ash with different combinations of simulated flue gas. The reaction between fly ash and 100% CO2 was relatively fast; the uptake of CO2 reached 87 g CO2/kg ash, and the sequestered CO2 could be entirely released at high temperatures. When CO2 content was reduced to 12%, the reaction rate decreased; the uptake fell to 41 g CO2/kg ash, and 70.7% of the sequestered CO2 could be released. With 12% CO2 in the presence of SO2, the reaction rate significantly decreased; the uptake was just 17 g CO2/kg ash, and only 52.9% of the sequestered CO2 could be released. SO2 in the simulated gas restricted the ability of fly ash to sequester CO2 because it blocked the pores of the ash.