Comparative assessment of gasification based coal power plants with various CO2 capture technologies producing electricity and hydrogen

Seven different types of gasification-based coal conversion processes for producing mainly electricity and in some cases hydrogen (H2), with and without carbon dioxide (CO2) capture, were compared on a consistent basis through simulation studies. The flowsheet for each process was developed in a chemical process simulation tool “Aspen Plus”. The pressure swing adsorption (PSA), physical absorption (Selexol), and chemical looping combustion (CLC) technologies were separately analyzed for processes with CO2 capture. The performances of the above three capture technologies were compared with respect to energetic and exergetic efficiencies, and the level of CO2 emission. The effect of air separation unit (ASU) and gas turbine (GT) integration on the power output of all the CO2 capture cases is assessed. Sensitivity analysis was carried out for the CLC process (electricity-only case) to examine the effect of temperature and water-cooling of the air reactor on the overall efficiency of the process. The results show that, when only electricity production in considered, the case using CLC technology has an electrical efficiency 1.3% and 2.3% higher than the PSA and Selexol based cases, respectively. The CLC based process achieves an overall CO2 capture efficiency of 99.9% in contrast to 89.9% for PSA and 93.5% for Selexol based processes. The overall efficiency of the CLC case for combined electricity and H2 production is marginally higher (by 0.3%) than Selexol and lower (by 0.6%) than PSA cases. The integration between the ASU and GT units benefits all three technologies in terms of electrical efficiency. Furthermore, our results suggest that it is favorable to operate the air reactor of the CLC process at higher temperatures with excess air supply in order to achieve higher power efficiency

Competitive H2S – CO2 absorption in reactive aqueous methyldiethanolamine solution: Prediction with ePC-SAFT

Reactive absorption of CO2 and H2S in aqueous methyldiethanolamine (MDEA) solutions is considered within the ePC-SAFT equation of state. We demonstrate that ePC-SAFT can be employed in a predictive manner without regression of additional temperature-correlated terms. Mixed system predictions are tested using a consistent set experimental data covering a wide range of temperatures (313 K\u2013413 K), partial pressures (0.001 kPa\u20131000 kPa), and MDEA mass fractions (0.05\u2013wMDEA 0.75 wMDEA). Predicted partial pressures for acid gas absorption show good agreement for low MDEA fractions (wMDEA < 0.5). Absorption selectivity in binary H2S + CO2 absorption is correctly predicted, with absolute average deviations of 57.18% and 79.32% for partial pressures of CO2 and H2S. We identify a significant deterioration in ePC-SAFT predictive power for the high-MDEA regime (wMDEA > 0.5), likely originating from underlying assumptions in the Debye-H\ufcckel electrolyte free energy treatment and representation of ionic species

Crafted:An exploratory database of simulated adsorption isotherms of metal-organic frameworks

Overview The files in this repository compose the Charge-dependent, Reproducible, Accessible, Forcefield-dependent, and Temperature-dependent Exploratory Database (CRAFTED) of adsorption isotherms. This dataset contains the simulation of CO2 and N2 adsorption isotherms on 690 metal-organic frameworks taken from the CoRE MOF 2014 database. The simulations were performed with two force fields (UFF and DREIDING), six partial charge schemes (no charges, Qeq, EQeq, DDEC, MPNN, and PACMOF), and three temperatures (273, 298, 323 K). Contents CIF_FILES/ contains 6 folders (NEUTRAL, DDEC, EQeq, Qeq, MPNN, and PACMOF), each one with 690 CIF files; FORCEFIELDS/ contains 2 folders (UFF and DREIDING) with the definition of the forcefields; INPUT_FILES/ contains 49,680 input files for the GCMC simulations; ISOTHERM_FILES/ contains 49,680 adsorption isotherms resulting from the GCMC simulation; ENTHALPY_FILES/ contains 49,680 enthalpies of adsorption from the isotherms; RAC_DBSCAN/ contains the RAC and geometrical descriptors to perform the t-NSE + DBSCAN analysis; Licenses The CIF files in the DDEC folder were downloaded from CoRE MOF 2014 and are licensed under the terms of the Creative Commons Attribution 4.0 International license (CC-BY-4.0). Dalar Nazarian, Jeffrey S. Camp, & David S. Sholl. (2016). Computation-Ready Experimental Metal-Organic Framework (CoRE MOF) 2014 DDEC Database [Data set]. Zenodo. The CO2.def and N2.def forcefield files were downloaded from RASPA and are licensed under the terms of the MIT license. RASPA: a molecular-dynamics, monte-carlo and optimization code for nanoporous materials. Copyright (C) 2006-2019 David Dubbeldam, Sofia Calero, Thijs Vlugt, Donald E. Ellis, and Randall Q. Snurr. The CIF files in the PACMOF, MPNN, Qeq, EQeq and NEUTRAL folders were derived from those in the DDEC folder and are licensed under the terms of the Creative Commons Attribution 4.0 International license (CC-BY-4.0). All remaining files are licensed under the terms of the CDLA-Sharing-1.0 license. Software requirements In order to create a Python environment capable of running the Jupyter notebooks, please install conda and execute conda env create --file environment.yml Usage instructions Execute the command below to run JupyterLab in the appropriate Python environment. conda run --name crafted jupyter-labCreated using "tar -Jcvf CRAFTED-1.1.1.tar.xz CRAFTED-1.1.1/"

Acid and Base Stress and Transcriptomic Responses in Bacillus subtilis▿†

Acid and base environmental stress responses were investigated in Bacillus subtilis. B. subtilis AG174 cultures in buffered potassium-modified Luria broth were switched from pH 8.5 to pH 6.0 and recovered growth rapidly, whereas cultures switched from pH 6.0 to pH 8.5 showed a long lag time. Log-phase cultures at pH 6.0 survived 60 to 100% at pH 4.5, whereas cells grown at pH 7.0 survived <15%. Cells grown at pH 9.0 survived 40 to 100% at pH 10, whereas cells grown at pH 7.0 survived <5%. Thus, growth in a moderate acid or base induced adaptation to a more extreme acid or base, respectively. Expression indices from Affymetrix chip hybridization were obtained for 4,095 protein-encoding open reading frames of B. subtilis grown at external pH 6, pH 7, and pH 9. Growth at pH 6 upregulated acetoin production (alsDS), dehydrogenases (adhA, ald, fdhD, and gabD), and decarboxylases (psd and speA). Acid upregulated malate metabolism (maeN), metal export (czcDO and cadA), oxidative stress (catalase katA; OYE family namA), and the SigX extracytoplasmic stress regulon. Growth at pH 9 upregulated arginine catabolism (roc), which generates organic acids, glutamate synthase (gltAB), polyamine acetylation and transport (blt), the K+/H+ antiporter (yhaTU), and cytochrome oxidoreductases (cyd, ctaACE, and qcrC). The SigH, SigL, and SigW regulons were upregulated at high pH. Overall, greater genetic adaptation was seen at pH 9 than at pH 6, which may explain the lag time required for growth shift to high pH. Low external pH favored dehydrogenases and decarboxylases that may consume acids and generate basic amines, whereas high external pH favored catabolism-generating acids