1,721,055 research outputs found
Comparative study on low and high pressure CO2 adsorption capacity of organic materials
No full textApplication of solid sorbents for CO2 capture and separation has been under consideration since last decades owing to the promising feature of repeatable use, low cost of regeneration and thermo physical stability. However, the capturing capacity, selectivity and the overall performance of adsorbents at different temperatures and pressures still require further investigation to make these materials capable of replacing the mono-ethanol system. Here in we report synthesis, characterization and application of covalent organic polymers. Capturing capacity of COPs at low temperature and pressure has been experimented for two COPs materials (namely COP-9, COP-10) for CO2 and N2 adsorption. Materials were also characterized with BET and TGA
Amidoxime porous polymers for CO2 capture
No full textCO2 capture from fossil fuel based electricity generation remains costly since new power plants with monoethanol amine (MEA) as the scrubbing agent are under construction. Amidoximes are known to mimic MEA, and porous polymers with amidoximes could offer a sustainable solution to carbon capture. Here we report the first amidoxime porous polymers (APPs) where aromatic polyamides (aramids) having amidoxime pendant groups were synthesized through low temperature condensation of 4,4'-oxydianiline (ODA) and p-phenylene diamine (p-PDA) with a new type of nitrile-bearing aromatic diacid chloride. The nitrile pendant groups of the polyamides were converted to an amidoxime functionality by a rapid hydroxylamine addition (APP-1 and APP-2). The CO2 adsorption capacities of these polyamides were measured at low pressure (1 bar) and two different temperatures (273 and 298 K) and high pressure (up to 225 bar - the highest measuring pressure to date) at 318 K. The low pressure CO2 uptake of APP-1 was found to be 0.32 mmol g(-1) compared with APP-2 (0.07 mmol g(-1)) at 273 K, whereas at high pressure they showed a substantial increase in CO2 adsorption capacity exhibiting 24.69 and 11.67 mmol g(-1) for APP-1 and APP-2 respectively. Both aramids were found to be solution processable, enabling membrane applications
High-capacity methane storage in flexible alkane-linked porous aromatic network polymers
No full textAdsorbed natural gas (ANG) technology is a viable alternative to conventional liquefied or compressed natural-gas storage. Many different porous materials have been considered for adsorptive, reversible methane storage, but fall short of the US Department of Energy targets (0.5 g(-1), 26311(-1)). Here, we prepare a flexible porous polymer, made from benzene and 1,2-dichloroethane in kilogram batches, that has a high methane working capacity of 0.625 g g(-1) and 29411(-1) when cycled between 5 and 100 bar pressure. We suggest that the flexibility provides rapid desorption and thermal management, while the hydrophobicity and the nature of the covalently bonded framework allow the material to tolerate harsh conditions. The polymer also shows an adsorbate memory effect, where a less adsorptive gas (N-2) follows the isotherm profile of a high-capacity adsorbate (CO2), which is attributed to the thermal expansion caused by the adsorption enthalpy. The high methane capacity and memory effect make flexible porous polymers promising candidates for ANG technology
Insights of CO2 adsorption performance of amine impregnated mesoporous silica (SBA-15) at wide range pressure and temperature conditions
No full textBeside IGCC, efficient storage and transportation of CO2 and other gases require pressurize conditions. CO2 and other gases adsorption on solid sorbents at high pressure and various temperatures are extremely important as long as the environmental purification via gas capture and separation and gas transpiration are concern. The main objective of the present research was to investigate the effect of amine impregnation on the CO2, methane and nitrogen adsorption capacity of mesoporous silica (SBA-15). Ordered mesoporous silica (SBA-15) was prepared and modified with ammonium hydroxide solution to introduce NH2 functional groups within the pores of materials to produce modified SBA-15 (MSBA-15). The newly prepared materials were characterized with X-ray diffraction analysis, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis were performed to measure pore volume as well as the surface area of both the unmodified and modified samples. Results revealed that the crystal structures of SBA-15 were matched with that of MSBA15; yet, pore volume of the modified material was almost reduced to 50% of the pristine material indicating amine loading into the pore channels. Importantly, gas sorption capacity was investigated at 200bars and three different temperatures of 318K, 328K, and 338K by using state-of-the-art gravimetric Rubotherm magnetic suspension sorption apparatus. Gas sorption experiments showed that modified mesoporous silica adsorbed 1.6164mmol/g of CO2 at 1bar which is almost double than that of 0.6462mmol/g adsorbed by unmodified material. Quantitative selectivity of both the materials varied as CO2>CH4>N2Scopu
DEEP EUTECTIC SOLVENT FOR CO2 CAPTURE: CHOLINIUM CHLORIDE WITH PHENYLACETIC ACID SYSTEM
Full text linkGlobal warming is one of the most pressing challenges that face societies these days. As result, worldwide public attention has risen due to the serious greenhouse gas effect, which causes detrimental environmental effects such as climate change. Carbon dioxide emission is considered as one of the most significant greenhouse gases activity involved in climate change. In power plants, these gases especially carbon dioxide are emitted by fossil fuels; therefore, capturing it will reduce the greenhouse effect.
Increasing energy demand is triggering increased usage of fossil based fuels, which cause unprecedented toxic gaseous emissions to atmosphere. Release of these gases is harmful to environment, especially CO2 as it increases the acidity and salinity of fresh and sea/ocean water sources. Due to increased global risk in caused by the toxic emissions, several options have been considered in both political and academic platforms in order to find feasible and sustainable emission control models. CO2 capture contributes to three fourths of the overall gaseous emissions capture activities and it has a cumulative negative cost side effect of 50% increase in electricity production in related industries. The choice of the suitable technology differs on the characteristics of the gas stream in which CO2 will be captures. Such characteristic depends on the type of the dynamics of the process through which the fuel is processes and used.
Deep Eutectic Solvents (DESs) are a novel, advanced class of solvents, which maintain the most relevant characteristics of ionic liquids (ILs), but can be prepared using a more facile and inexpensive method. This alternative approach is based on producing eutectic mixtures of salts and hydrogen-bonding donors (HBDs).
The purpose behind this study is to examine a new system of DES system which is Choline chloride/ Phenylacetic acid (ChCl/PAA) for CO2 capture. The CO2 solubility as function of temperature and pressure, with other relevant physicochemical properties including density, conductivity, corrosion, surface tension, Fourier Transform Infrared (FTIR) and Thermogravimetric analysis (TGA) characterizations are reported to analyze DES system and its capability for capturing the CO2. Experimental studies of DES that reported in this work showed that this sort of eutectic solvents have appreciable performance of CO2 at low corrosion effect in compared with monoethanolamine (MEA).
CO2 absorption estimated by studying the behavior of the liquid –gas and interface properties. CO2/N2 solubility values were determined using high magnetic sorption apparatus (MSA) of Rubotherm at temperature 298.15 up to 338.15 K and pressure up to 30 bars. It’s conclude that the ChCl/PAA DES system with molar ratio of 1:2 absorbed 2.10 mmol/g of CO2 at 308.15 K and 30 bar, with the same conditions ChCl/ Levulinic Acid system absorbed the same amount of CO2, while ChCl/ethylene glycol absorbed 3.1265 mmol/g of CO2 at 303.15 K and 58.63 bars. The amount of absorption of ChCl/PAA increase to 3.35 mmol /g of CO2 by increasing the molar ratio to 1:3 at the same temperature and pressure of the 1:2 molar ratio . In compared with amine based, solid amine sorbent, consisting of poly (ethylenimine) (PEI) absorbed 2.8 mol/kg of CO2 at 353.15 K and partial pressures more than 10kPa (0.1 bar). Moreover, in compared with the most known amine in industry MEA, DES (1:3) at 30 bars and 308 K absorbed 3.35 mmol/g CO2 while MEA at 24 bars and 313 K absorbed 2.66 mmol/g CO2.
The non-toxic, low cost and the other advantages of reported eutectic solvent with favorable physical properties offers an environmentally promising alternative for effective CO2 capture technological applications
HIGH PRESSURE CO2/N2 AND CO2/CH4 SEPARATION USING DENSE POLYSULFONE SUPPORTED IONIC LIQUID MEMBRANES (DPSILMS)
Full text linkThe separation of carbon dioxide from different sources (e.g. natural gas, flue gas, etc.) has become an important area of research. Some conventional methods of CO2 separation were used over the years including adsorption (with porous solids), absorption (with amines), cryogenic separation and membranes. Amongst these technologies, Supported Ionic Liquid Membranes (SILMs) technology has been developed in the past few years and became one of the promising techniques in CO2 separation from gas streams. SILMs technology combines the advantages of both membranes and ionic liquids (ILs) hence it has become an interest of many recent studies. Most of the synthesized SILMs in literature uses porous membranes to support the ionic liquids. Although these SILMs achieve high permeability of CO2, the separation selectivity to the other gas is very low due to the high permeance of the other gas. Another drawback of porous SILMs is the membrane failure with high pressures due to ionic liquid loss through the pores of the support membrane.
In this work, we look alternative solutions to overcome these disadvantages by synthesizing SILMs using dense (non-porous) polymeric support by which limiting or eliminating ILs loss through the membrane and increase the selectivity of CO2 separation. Four types of ionic liquids (ILs) were blended with polysulfone (PSF) to produce functional dense polymeric-supported ionic liquid membranes (DPSILMs). These ionic liquids are 1-alkyl-3-methylimidazolium bistriflamide [C4mim][NTf2] and Di-iso-propyl 1-alkyl-3-methylimidazolium bistriflamide [DIP-C4mim][NTf2], Tributylmethylphosphonium formate [P4441][formate], and Tributylmethylammonium formate [N4441][formate].
The main aim of this study is to investigate the potential use of the synthesized DPSILMs in the industrial gas processing applications for high-pressure CO2 separation from N2 and CH4 streams with less or no loss of ILs. The synthesized DPSILMs were analysed using FTIR and SEM and showed a clear chemical and physical change in the structure PSF and well distribution of ILs in PSF. Binary mixtures of CO2/N2 and CO2/CH4 (5 mol% CO2) were used in the study. Selectivity values for the prepared DPSILMs were obtained using a high-pressure membrane unit obtained from Rubotherm Präzisionsmesstechnik GmbH apparatus (System 2). The highest CO2/N2 selectivity values were 36 for both PSF-0.5 wt% [DIP-C4mim][NTf2], PSF-25 wt% [N4441][formate], 29 and 21 for PSF-0.5 wt% [C4mim][NTf2] and PSF-50 wt% [P4441][formate] respectively. Whereas the highest CO2/CH4 selectivity results were 70, 63, 47, and 32 for PSF-2.5 wt% [C4mim][NTf2], PSF-2.5 wt% [DIP-C4mim][NTf2], PSF-0.5 wt% [N4441][formate], and PSF-5 wt% [P4441][formate] respectively. Another system was used to measure the permeability of each gas (System 1) to be plotted then on Robeson's upper bound (2008) with other PSF blends in the literature for better comparison. The plot showed that the synthesized DPSILMs gave satisfying results and behave as well or better than different types of reported PSF blends. The highest CO2 permeabilities (with CO2/N2 separation measurements) obtained with each IL were 19, 13.6, 10.8, and 8.9 barrer with PSF-25 wt% [N4441][formate], PSF-5 wt% [p4441][formate], PSF-0.5 wt% [DIP- C4mim][NTf2], and PSF-5 wt% [C4mim][NTf2] respectively. However with CO2/CH4 separation measurements, the highest CO2 permeabilities were 17.3, 13.8, 12.5, and 11.5 barrer with PSF-12.5 wt% [P4441][formate], PSF-2.5 wt% [DIP-C4mim][NTf2], PSF-0.5 wt% [N4441][formate], and PSF-2.5 wt% [C4mim][NTf2] respectively.
Stability measurements of the synthesized DPSILMs were conducted regarding ILs loss and CO2/CH4 separation efficiency. Stability results showed that DPSILMs with 5 wt% [P4441][formate] and [N4441][formate] showed about 30% and 20% ILs loss respectively at 10 bar after 12 hours with small reduction in CO2/CH4 selectivity; while no loss of [DIP-C4mim][NTf2] and [C4mim][NTf2] was observed.Qatar National Research Fund (a member of Qatar Foundation) under NPRP Grant # [09-739-2-284
Limitations and high pressure behavior of MOF-5 for CO2 capture
No full textPorous network structures (e.g. metal–organic frameworks, MOFs) show considerable potential in dethroning monoethanol amine (MEA) from being the dominant scrubber for CO2 at the fossil-fuel-burning power generators. In contrast to their promise, structural stability and high-pressure behavior of MOFs are not well documented. We herein report moisture stability, mechanical properties and high-pressure compression on a model MOF structure, MOF-5. Our results show that MOF-5 can endure all tested pressures (0–225 bar) without losing its structural integrity, however, its moist air stability points at a 3.5 hour safety window (at 21.6 °C and 49% humidity) for an efficient CO2 capture. Isosteric heats of CO2 adsorption at high pressures show moderate interaction energy between CO2 molecules and the MOF-5 sorbent, which combined with the large sorption ability of MOF-5 in the studied pressure–temperature ranges show the viability of this sorbent for CO2 capturing purposes. The combination of the physicochemical methods we used suggests a generalized analytical standard for measuring viability in CO2 capture operations.Scopu
Gas Hydrate Equilibrium Measurements for Multi-Component Gas Mixtures and Effect of Ionic Liquid Inhibitors
Full text linkQatar holds the world's third-largest proven reserves of natural gas at 885 trillion cubic feet according to a recent report. Because of its desert climate, gas hydrate formation may seem an unlikely event in Qatar. However, its natural gas reservoirs are located 80 km offshore, in the North Field, and the production of liquefied natural gas (LNG) depends on reliable flow from offshore wellheads to onshore processing facilities. Classical methods for inhibiting hydrate formation are used in order to prevent pipeline plugging but changing gas concentrations and operating conditions make flow assurance quite challenging in the North Field. Between 2008 and 2011, sudden temperature drops near gas pipelines caused various incidents of gas pipeline blockage by hydrates, with a loss of US$ 10 million per day due to lost production for almost 4 weeks. Such unplanned shut downs jeopardize the reliable export of LNG to end users.
This work presents the recent investigation on synthetic multi-component gas mixtures whose compositions are typical of Qatari natural gases with initiatives aimed at helping producers minimize costs, optimize operations, and prevent interruption of gas flow in offshore drilling and production. In addition, it presents hydrate inhibition data from a newly commissioned micro bench top reactor, a high-pressure autoclave and a rocking cell. The conditions for hydrate formation for pure methane and carbon dioxide were also measured, for validation purposes. The measured data were compared with literature results and those of a commercial simulator, HydraFLASH��. Upon validation of the calibration data and determination of the apparatus uncertainty, results for hydrate formation equilibrium points for Qatari natural gas sample were collected and compared to HydraFLASH�� predictions. Different percentages of 2-hydroxy-N,N,N-trimethylethanaminium chloride, also known as choline chloride ionic liquid, were used as hydrate inhibitor for the same gas mixture. The ionic liquid���s inhibition performance was compared to that of classical thermodynamic inhibitors (e.g. methanol). Ionic liquid inhibition showed (0.7 ��� 1.8) oC and (2 - 2.6) oC shift in the hydrate equilibrium curve with 1 wt. % and 5 wt. % of choline chloride respectively. While the inhibition performance of 1 wt. % and 5 wt. % of methanol, obtained using HydraFLASH�� software, were 2.8 oC and 4.4 oC respectively
High accuracy p-rho-t measurements up to 200 MPa between 200 K and 500 K using a compact single sinker magnetic suspension densimeter for pure and natural gas like mixtures
Full text linkHighly accurate density data is required for engineering calculations to make
property estimations in natural gas custody transfer through pipelines. It is also essential
to have accurate pressure-volume-temperature (PVT) data for developing equations of
state (EOS). A highly accurate, high pressure and temperature, compact single sinker
magnetic suspension densimeter has been used for density measurements. First, the
densimeter is calibrated against pure component densities for which very reliable data
are available. After validating its performance, the densities of four light natural gas
mixtures that do not contain components heavier than hexane and two heavy gas
mixtures containing hexane and heavier components having fractions more than 0.2
mole percent were measured. The light mixtures were measured in the temperature range
of 250 to 450 K and in the pressure range of 10 to 150 MPa (1450 to 21,750 psi); the
heavy mixtures were measured in the range of 270 to 340 K and in the pressure range of
3 to 35 MPa (500 to 5,000 psi). Out of those, the data for only four light natural gas
mixtures have been presented in the dissertation due to confidentiality agreements that
are still in force. A force transmission error and uncertainty analysis was carried out. The
total uncertainty was calculated to be 0.11%. Data calculated in this work is compared
with the current industry standard EOS for natural gas systems (AGA8-DC92 EOS) and
GERG EOS, which is the most recently developed EOS for natural gas systems. The
data measured as a part of this research should be used as reference quality data, either to
modify the parameters of AGA8-DC92 EOS and GERG EOS or to develop a more
reliable equation of state with wider ranges of pressure and temperature
A new cubic equation of state
Full text linkThermodynamic properties are essential for the design of chemical processes, and they are most useful in the form of an equation of state (EOS). The motivating force of this work is the need for accurate prediction of the phase behavior and thermophysical properties of natural gas for practical engineering applications. This thesis presents a new cubic EOS for pure argon. In this work, a theoretically based EOS represents the PVT behavior of pure fluids. The new equation has its basis in the improved Most General Cubic Equation of State theory and forecasts the behavior of pure molecules over a broad range of fluid densities at both high and low pressures in both single and multiphase regions. With the new EOS, it is possible to make accurate estimations for saturated densities and vapor pressures. The density dependence of the equation results from fitting isotherms of test substances while reproducing the critical point, and enforcing the critical point criteria. The EOS includes analytical functions to fit the calculated temperature dependence of the new EOS parameters
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