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1.
Mixed gases injection into a large coal sample for CO2 sequestration in coals and enhanced coalbed methane recovery was investigated using a new numerical approach. A dynamic multi-component transport (DMCT) model was applied to simulate ternary gas (CH4-CO2-N2) diffusion and flow behaviors for better understanding and prediction of gas injection enhanced coalbed methane (ECBM) recovery processes. Several cases were designed to analyze the effects of injection gas composition and pressure on gas displacement dynamics in a large coal sample. The calculated results suggest that mixed gas injections have similar profiles of methane recovery as pure N2 injection, and mixtures of N2 and CO2 reduce the ultimate methane recovery compared to pure CO2. The breakthrough time of pure CO2 injection is longer than mixed gas injections. Injection gas composition has significant effect on produced gas composition. 相似文献
2.
《The Journal of Supercritical Fluids》2009,48(3):619-627
The recovery of coalbed methane can be enhanced by injecting CO2 in the coal seam at supercritical conditions. Through an in situ adsorption/desorption process the displaced methane is produced and the adsorbed CO2 is permanently stored. This is called enhanced coalbed methane recovery (ECBM) and it is a technique under investigation as a possible approach to the geological storage of CO2 in a carbon dioxide capture and storage system. This work reviews the state of the art on fundamental and practical aspects of the technology and summarizes the results of ECBM field tests. These prove the feasibility of ECBM recovery and highlight substantial opportunities for interdisciplinary research at the interface between earth sciences and chemical engineering. 相似文献
3.
Geoff G.X. WANG Xiaodong ZHANG Xiaorong WEI Xuehai FU Bo JIANG Yong QIN 《Frontiers of Chemical Science and Engineering》2011,5(2):139
This paper presents a summary review on mass transport of coal seam gas (CSG) in coal associated with the coalbed methane (CBM) and CO2 geo-sequestration enhanced CBM (CO2-ECBM) recovery and current research advances in order to provide general knowledge and fundamental understanding of the CBM/ECBM processes for improved CBM recovery. It will discuss the major aspects of theory and technology for evaluation and development of CBM resources, including the gas storage and flow mechanism in CBM reservoirs in terms of their differences with conventional natural gas reservoirs, and their impact on CBM production behavior. The paper summarizes the evaluation procedure and methodologies used for CBM exploration and exploitation with some recommendations. 相似文献
4.
《Fuel》2007,86(12-13):1873-1884
This paper presents the development of an analytical model which can be used to relate the structural parameters of coal to its mechanical properties such as elastic modulus and Poisson’s ratio under a confined stress condition. This model is developed primarily to support process modeling of coalbed methane (CBM) or CO2-enhanced CBM (ECBM) recovery from coal seam. It applied an innovative approach by which stresses acting on and strains occurring in coal are successively combined in rectangular coordinates, leading to the aggregated mechanical constants. These mechanical properties represent important information for improving CBM/ECBM simulations and incorporating within these considerations of directional permeability. The model, consisting of constitutive equations which implement a mechanically consistent stress–strains correlation, can be used as a generalized tool to study the mechanical and fluid behaviors of coal composites. An example using the model to predict the stress–strain correlation of coal under triaxial confined stress by accounting for the elastic and brittle (non-elastic) deformations is discussed. The result shows a good agreement between the prediction and the experimental measurement. 相似文献
5.
Elaheh Mehrvarz Ali Asghar Ghoreyshi Mohsen Jahanshahi 《Korean Journal of Chemical Engineering》2017,34(2):413-424
A low-cost activated carbon (AC) was produced from the broom sorghum stalk using KOH as the chemical activating agent, and then the surface of AC was functionalized with diethanolamine to enhance CO2/CH4 selectivity. Characteristics of pristine and DEA-functionalized ACs were determined through different analyses such as Boehm’s method, BET, FT-IR, SEM, and TGA. The adsorption behavior of pure carbon dioxide and pure methane on these adsorbents was investigated in a temperature range of 288-308 K and pressure range of 0-25 bar using an apparatus based on a volumetric method. Results indicated that amine functionalization significantly improved the selectivity of CO2/CH4. The enhancement of CO2 ideal adsorption selectivity over CH4 from 1.51 for the pristine AC to 5.75 for the AC-DEA was attributed to adsorbate-adsorbent chemical interaction. The present DEA-functionalized AC adsorbent can be a good candidate for applications in natural gas and landfill gas purifications. 相似文献
6.
Aluminum terephthalate, MIL-53(Al), metal–organic framework synthesized hydrothermally and purified by solvent extraction
method was used as an adsorbent for gas adsorption studies. The synthesized MIL-53(Al) was characterized by powder X-Ray diffraction
analysis, surface area measurement using N2 adsorption–desorption at 77 K, FTIR spectroscopy and thermo gravimetric analysis. Adsorption isotherms of CO2, CH4, CO, N2, O2 and Ar were measured at 288 and 303 K. The absolute adsorption capacity was found in the order CO2>CH4>CO>N2>Ar>O2. Henry’s constants, heat of adsorption in the low pressure region and adsorption selectivities for the adsorbate gases were
calculated from their adsorption isotherms. The high selectivity and low heat of adsorption for CO2 suggests that MIL-53(Al) is a potential adsorbent material for the separation of CO2 from gas mixtures. The high selectivity for CH4 over O2 and its low heat of adsorption suggests that MIL-53(Al) could also be a compatible adsorbent for the separation of methane
from methane–oxygen gas mixtures. 相似文献
7.
Discovery of novel zeolites for natural gas purification through combined material screening and process optimization
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Christodoulos A. Floudas 《American Institute of Chemical Engineers》2014,60(5):1767-1785
An efficient computational screening approach is proposed to select the most cost‐effective materials and adsorption process conditions for CH4/CO2 separation. The method identifies eight novel zeolites for removing CO2 from natural gas, coalbed methane, shale gas, enhanced oil recovery gas, biogas, and landfill gas sources. The separation cost is minimized through hierarchical material screening combined with rigorous process modeling and optimization. Minimum purity and recovery constraints of 97 and 95%, respectively, are introduced to meet natural gas pipeline specifications and minimize losses. The top zeolite, WEI, can recover methane as economically as $0.15/MMBTU from natural gas with 5% CO2 to $1.44/MMBTU from natural gas with 50% CO2, showing the potential for developing natural gas reservoirs with higher CO2 content. The necessity of a combined material selection and process optimization approach is demonstrated by the lack of clear correlation between cost and material‐centric metrics such as adsorption selectivity. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1767–1785, 2014 相似文献
8.
Congmin Liu Yaping Zhou Yan Sun Wei Su Li Zhou 《American Institute of Chemical Engineers》2011,57(3):645-654
A PSA cycle complemented with CO2 displacement was studied for enriching coal‐bed methane (CBM). The column was first pressurized to the adsorption pressure with feed gas, and then N2 was produced at column top in step 2. The feed gas switched to CO2 at the end of step 2, and the adsorbed CH4 was displaced and pushed to column top by CO2 becoming the second column‐top product in step 3. The CO2 stream was shut off before it broke through the sorption bed. Then bed regeneration followed. A series of CH4/N2 mixtures containing 17.62 to 51.33% CH4 was used for feed gas. It was experimentally shown that the product concentration was higher than 90%, and methane recovery was higher than 98% even for the feed of low‐methane concentration. Displacement at ambient pressure was shown more efficient than the displacement at adsorption pressure for the enrichment. © 2010 American Institute of Chemical Engineers AIChE J, 2011 相似文献
9.
Kasra Pirzadeh Ali Asghar Ghoreyshi Mostafa Rahimnejad Maedeh Mohammadi 《Korean Journal of Chemical Engineering》2018,35(4):974-983
The electrochemical route is a promising and environmentally friendly technique for fabrication of metal organic frameworks (MOFs) due to mild synthesis condition, short time for crystal growth and ease of scale up. A microstructure Cu3(BTC)2 MOF was synthesized through electrochemical path and successfully employed for CO2 and CH4 adsorption. Characterization and structural investigation of the MOF was carried out by XRD, FE-SEM, TGA, FTIR and BET analyses. The highest amount of carbon dioxide and methane sorption was 26.89 and 6.63 wt%, respectively, at 298 K. The heat of adsorption for CO2 decreased monotonically, while an opposite trend was observed for CH4. The results also revealed that the selectivity of the developed MOF towards CO2 over CH4 enhanced with increase of pressure and composition of carbon dioxide component as predicted by the ideal adsorption solution theory (IAST). The regeneration of as-synthesized MOF was also studied in six consecutive cycles and no considerable reduction in CO2 adsorption capacity was observed. 相似文献
10.
Pb, Sb, Bi and Te doped Ni catalysts were prepared and used for methane reforming with CO2 in order to diminish coke deposition. It was found that small amounts of Pb doped Ni catalysts exhibited excellent coke resistance ability with minor loss of the reforming activity. As the added amount of Pb increased from 0 to 0.015 (mole ratio between Pb/Ni), coke formation rate decreased from 166.7 mg-coke/g-cat h (on Ni/SiO2) to 0, while the reforming activity decreased slightly from 73.2% to 63.3% (conversion of CO2) at 800 °C, 60,000 ml(STP)/g-cat·h (CH4 CO2=1:1, no dilution gas in feed). Higher amounts of Pb and Sb, Bi, Te made Ni catalyst deactivated for methane reforming with CO2. 相似文献
11.
Hyun Min Shim Joon Soo Lee Hong Yue Wang Seung Hak Choi Jeong Hoon Kim Hyung Taek Kim 《Korean Journal of Chemical Engineering》2007,24(3):537-541
The main purpose of the study was to develop a model using ASPEN and Excel simulation method to establish optimum CO2 separation process utilizing hollow fiber membrane modules to treat exhaust gas from LNG combustion. During the simulation,
optimum conditions of each CO2 separation scenario were determined while operating parameters of CO2 separation process were varied. The characteristics of hollow fibers membrane were assigned as 60 GPU of permeability and
25 of selectivity for the simulation. The simulation results illustrated that 4 stage connection of membrane module is required
in order to achieve over 99% of CO2 purity and 90% of recovery rate. The resulted optimum design and operation parameters throughout the simulation were also
correlated with the experimental data from the actual CO2 separation facility which has a capacity of 1,000 Nm3/day located in the Korea Research Institute of Chemical Technology. Throughout the simulation, the operating parameters of
minimum energy consumption were evaluated. Economic analysis of pilot scale of CO2 separation plant was done with the comparison of energy cost of CO2 recovery and equipment cost of the plant based on the simulation model.
This work was presented at the 6
th
Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006. 相似文献
12.
The global energy system is characterized by a gradual de-carbonization and move to cleaner burning technologies: from wood
to coal to oil and to natural gas. A final destination characterized by the term“hydrogen economy” is desired. Gas hydrate
found in the earth’s crust is considered a source of natural gas that is essentially 100% methane (CH4) gas. Natural gas hydrate estimates worldwide range from 10,000 to 40,000 trillion cubic meters (TCM). Efforts are underway
to exploit this resource. These methane hydrates in the earth’s crust also have the potential to be a significant factor in
global climate change. Moreover, gas hydrates offer opportunities for the development of innovative technologies (separation
of CO2 from CO2/N2 and CO2/H2 mixtures, CO2 sequestration, natural gas transportation and storage and H2 storage). In this work we assess the progress towards exploitation of gas hydrates as a resource for methane (cleaner energy)
and summarize the state of the art with respect to the role of gas hydrates in the development of innovative technologies. 相似文献
13.
Soodabeh Khalili Behnam Khoshandam Mohsen Jahanshahi 《Korean Journal of Chemical Engineering》2016,33(10):2943-2952
Adsorption of pure carbon dioxide and methane was examined on activated carbon prepared from pine cone by chemical activation with H3PO4 to determine the potential for the separation of CO2 from CH4. The prepared adsorbent was characterized by N2 adsorption-desorption, elemental analysis, FTIR, SEM and TEM. The equilibrium adsorption of CO2 and CH4 on AC was determined at 298, 308 and 318 K and pressure range of 1–16 bar. The experimental data of both gases were analyzed using Langmuir and Freundlich models. For CO2, the Langmuir isotherm presented a perfect fit, whereas the isotherm of CH4 was well described by Freundlich model. The selectivity of CO2 over CH4 by AC (CO2: CH4=50: 50, 298K, 5 bar), predicted by ideal adsorbed solution theory (IAST) model, was achieved at 1.68. These data demonstrated that pine cone-based AC prepared in this study can be successfully used in separation of CO2 from CH4. 相似文献
14.
The temperature profiles in a monolith reactor were measured in CO2 reforming of CH4 within-situ combustion of methane and ethane in order to find out in what sequence the reactions are occurring. The reaction gas flowed
both upward and downward. A hot spot was observed at low furnace temperatures, and it tended to disappear as the furnace temperature
increased. This is due to natural extinguishment of the flame caused by the endothermic reforming reactions occurring. The
hot spot disappeared at a lower temperature with the up-flow when compared with the down-flow. When the hot spot appears,
H2O and CO2 are produced by complete oxidation and accordingly the steam reforming and the CO2 reforming occur competitively in the rear part of the monolith. If the hot spot does not appear, it is considered that the
partial oxidation of methane occurs predominantly over the complete oxidation, resulting in more efficient CO2 removal. 相似文献
15.
16.
S. O. Soloviev 《Catalysis in Industry》2012,4(1):1-10
The catalytic properties of Ni/Al2O3 composites supported on ceramic cordierite honeycomb monoliths in oxidative methane reforming are reported. The prereduced
catalyst has been tested in a flow reactor using reaction mixtures of the following compositions: in methane oxidation, 2–6%
CH4, 2–9% O2, Ar; in carbon dioxide and oxidative carbon dioxide reforming of methane, 2–6% CH4, 6–12% CO2, and 0–4% O2, and Ar. Physicochemical studies include the monitoring of the formation and oxidation of carbon, the strength of the Ni-O
bond, and the phase composition of the catalyst. The structured Ni-Al2O3 catalysts are much more productive in the carbon dioxide reforming of methane than conventional granular catalysts. The catalysts
performance is made more stable by regulating the acid-base properties of their surface via the introduction of alkali metal
(Na, K) oxides to retard the coking of the surface. Rare-earth metal oxides with a low redox potential (La2O3, CeO2) enhance the activity and stability of Ni-Al2O3/cordierite catalysts in the deep and partial oxidation and carbon dioxide reforming of methane. The carbon dioxide reforming
of methane on the (NiO + La2O3 + Al2O3)/cordierite catalyst can be intensified by adding oxygen to the gas feed. This reduces the temperature necessary to reach
a high methane conversion and does not exert any significant effect on the selectivity with respect to H2. 相似文献
17.
Humair Ahmed Baloch Tianhua Yang Haipeng Sun Jie Li Sabzoi Nizamuddin Rundong Li Zhanguo Kou Yang Sun Abdul Waheed Bhutto 《Korean Journal of Chemical Engineering》2016,33(9):2567-2574
A parametric study of pyrolysis and steam gasification of rice straw (RS) was performed to investigate the effect of the presence of K2CO3 on the behavior of gas evolution, gas component distribution, pyrolysis/gasification reactivity, the quality and volume of synthetic gas. During pyrolysis, with the increase in K2CO3 content in RS (i) the instantaneous CO2 concentration was increased while CO concentration was relatively stable; (ii) the yield of CO2 and H2 increased on the cost of CH4. During steam gasification of RS, with the increase in K2CO3 content in RS (i) the instantaneous concentration of CO2 and H2 increased while instantaneous concentration of CO and CH4 decreased; (ii) the yield of CO2 and H2 production and total yield increased; and (iii) yield of CO and CH4 production followed the order: 9% K2CO3 RS<6% K2CO3 RS<raw RS<3% K2CO3 RS<water-leached RS. Water-leached RS showed the highest pyrolysis reactivity, while stream gasification reactivity was proportional to K2CO3 content in RS. The results of this study reveal that the presence of K2CO3 during pyrolysis and steam gasification of RS effectively improves production of H2 rich gas. 相似文献
18.
Abolfazl Jomekian Reza Mosayebi Behbahani Toraj Mohammadi Ali Kargari 《Korean Journal of Chemical Engineering》2017,34(2):440-453
Modified ultra-porous ZIF-8 particles were used to prepare novel ZIF-8/Pebax 1657 mixed matrix membranes (MMMs) on PES support for separation of CO2 from CH4 using spin coating method. TEM and SEM were used to characterize modified ZIF-8 particles. SEM was also used to investigate the morphology of synthesized MMMs. The MMMs with thinner selective layer showed higher CO2 permeability and lower CO2/CH4 selectivity in permeation tests compared to MMMs with thicker selective layer. The plasticization was recognized as the main reason for rise in CO2 permeability and drop in CO2/CH4 selectivity of thinner MMMs. The gas sorption results showed that the high permeability of CO2 in MMMs is mainly due to the high solubility of this gas in MMMs, leading to high CO2/CH4 solubility selectivity for MMMs. The fractional free volume and void volume fraction of MMMs increased as the thickness of membrane decreased. Applying higher mixed feed pressures and permeation tests temperatures resulted in increase in CO2 permeability and decrease in CO2/CH4 selectivity. At highest testing temperature (60 °C), the CO2 permeability of synthesized MMMs with thinner selective layer remarkably increased. 相似文献
19.
Qilei Song Rui Xiao Zhongyi Deng Laihong Shen Mingyao Zhang 《Korean Journal of Chemical Engineering》2009,26(2):592-602
Chemical-looping combustion (CLC) is a promising technology for the combustion of gas or solid fuel with efficient use of
energy and inherent separation of CO2. A reactivity study of CaSO4 oxygen carrier in CLC of methane was conducted in a laboratory scale fixed bed reactor. The oxygen carrier particles were
exposed in six cycles of alternating reduction methane and oxidation air. A majority of CH4 reacted with CaSO4 to form CO2 and H2O. The oxidation was incomplete, possibly due to the CaSO4 product layer. The reactivity of CaSO4 oxygen carrier increased for the initial cycles but slightly decreased after four cycles. The product gas yields of CO2, CH4, and CO with cycles were analyzed. Carbon deposition during the reduction period was confirmed with the combustible gas (CO+H2) in the product gas and slight CO2 formed during the early stage of oxidation. The mechanism of carbon deposition and effect was also discussed. SO2 release behavior during reduction and oxidation was investigated, and the possible formation mechanism and mitigation method
was discussed. The oxygen carrier conversion after the reduction decreased gradually in the cyclic test while it could not
restore its oxygen capacity after the oxidation. The mass-based reaction rates during the reduction and oxidation also demonstrated
the variation of reactivity of CaSO4 oxygen carrier. XRD analysis illustrated the phase change of CaSO4 oxygen carrier. CaS was the main reduction product, while a slight amount of CaO also formed in the cyclic test. ESEM analysis
demonstrated the surface change of particles during the cyclic test. The reacted particles tested in the fixed bed reactor
were not uniform in porosity. EDS analysis demonstrated the transfer of oxygen from CaSO4 to fuel gas while leaving CaS as the dominant reduced product. The results show that CaSO4 oxygen carrier may be an interesting candidate for oxygen carrier in CLC.
This work was presented at the 7
th
China-Korea Workshop on Clean Energy Technology held at Taiyuan, China, June 26–28, 2008. 相似文献
20.
Mahdi Pourafshari Chenar Houman Savoji Mohammad Soltanieh Takeshi Matsuura Shahram Tabe 《Korean Journal of Chemical Engineering》2010,27(6):1876-1881
Impurities such as hydrogen sulfide, water vapor and heavy hydrocarbons in natural gas have considerable effects on the membrane
performance. Small amounts of condensable and polymer soluble components in the feed gas cause swelling or plasticization
of glassy membranes, leading to a reduction in membrane selectivity. In the present research the influence of ethane was investigated
on the permeance and selectivity of two commercially available hollow fiber membranes, namely Cardo-type polyimide and PPO
hollow fibers for CO2/CH4 separations. It was concluded that the gas mixture permeation rate was increased in the presence of C2H6. However, the CO2/CH4 separation factors remained almost the same in the presence and absence of the C2H6. 相似文献