Methyldiethanolamine Research Articles

Potential use of coconut husk-based magnetic sorbent for defoaming application

Absorption process is the most common method that is being applied to sweeten sour gas in the oil and gas industry. However, this process does have several consequences which will trigger the foam formation of foam that will reduce the mass transfer efficiency and absorption capacity as well as amine solutions carryover to the downstream processes. The removal of undesired contaminants in activated methyldiethanolamine (MDEA) was conducted by utilizing magnetic activated carbon (MAC). In this work, MAC was synthesized from coconut husk through chemical activation and co-precipitation methods. The performance of this material as an adsorbent was evaluated based on the foaming behaviour of activated MDEA solvent after being contacted with MAC at different duration and varying amounts. Nitrogen gas was introduced into the solvent through a gas diffuser to create foam. Based on the results, the foam volume generated by activated MDEA solvent was identified to decrease with the increase in both MAC contact time and amount. The highest removal efficiency by MAC was identified to be at 1 h contact time between MAC and activated MDEA solvent where the foam breaking time was reduced to 10–30 min. Meanwhile, the addition of 50 % MAC into the solvent was able to further decrease the foam breaking time to 5–10 min. The characteristics of the prepared MAC were evaluated through various instrumental analyses. This study shows that the MAC synthesized from coconut husk has a good potential as an adsorbent in removing the contaminants in activated MDEA solvent to reduce foam formation.

Rate-based modeling and energy optimization of acid gas removal from natural gas stream using various amine solutions

Reduction in energy consumption of industrial plants is always an essential need due to high cost, CO2 emissions and global warming caused by energy supply from fossil fuels for boilers and electricity consumers. Iran has been struggling to compensate the lack of gas supply for domestic and industrial demands in winter within the past decade despite of having large natural gas resources. One of the most economical methods to decrease energy requirements in hydrocarbon plants is process improvement and revamping by changing existing solvents. There are already 44 identical acid gas removal units under operation in the South Pars Gas Complex (located in Iran) with the same feed composition. The gas-sweetening unit in the Phase 12, operating with the solution of 45.5 wt% methyldiethanolamine (MDEA), was modeled by Aspen Plus for acid gas removal (CO2 and H2S) as a rate-based model with the application of electrolyte non–random two–liquid (E-NRTL) activity model and Peng–Robinson equation of state in addition to the actual characteristics of the absorber and regenerator, and the operational conditions of the gas and liquid streams. After validation of the model by the real data from the plant, the incumbent amine solution was replaced with five proposed amine solutions – one single and four blended amine mixtures – in the same mass concentration to select the most efficient alternative from the aspects of outlet acid gas concentration, H2S content in the treated flash gas, required total power, reboiler power supply, and regeneration heat duty. The simulation results revealed that H2S was sharply absorbed on the top of the column, while CO2 was smoothly removed from the gas phase to the MDEA and blended solutions along the absorber and it occurred at the bottom of the column for the DEA solution. The blended amine solution of 1.5 wt% sulfolane + 44 wt% MDEA (Sulfinol-M) has shown to be the most appropriate option instead of the solution of MDEA compared to other suggested absorbents, with several advantages such as higher selectivity of H2S over CO2, low temperature bulge, highest H2S loading, and outlet sweet gas flow rate while required total power, reboiler power supply, and regeneration heat duty were reduced by 21.19%, 21.26%, and 23.54% respectively. The operational conditions of the unit with the application of the Sulfinol-M solution were optimized to achieve three specifications (constraints) and the minimum required total power (objective function) through a sensitivity analysis and optimization using a genetic algorithm to assure the reliability of values for three independent parameters, namely, amine solution temperature, amine solution flow rate, and gas temperature. The optimum limits and values of these parameters were 47–50 °C, 220 – 240 ton/h, and 34 °C respectively.

Modeling and Simulation of CO2 Capture Unit using Mixed Solvent of Aqueous Methyldiethanolamine and Piperazine for 6.4 MWe Power Plant

Carbon dioxide emissions are the largest greenhouse gases contributor, which is attributed to global warming. Therefore, the capture of CO2 is necessary, especially from large point sources. Post-combustion capture using chemical solvents is the most matured capture technology. In this paper, mixed solvents of methyldiethanolamine (MDEA) and piperazine (PZ) were studied to potentially address some issues related to the use of conventional monoethanolamine (MEA). Steady-state modeling and simulation of the post-combustion carbon capture using the mixed solvents for a typical 6.4 MWe power plant were done. The model developed was validated against experimented data with relative error between 1 – 4.73% for the absorber on CO2 capture efficiency and between 2.93 – 10.2% relative errors on CO2 regeneration efficiency. The model was scaled up to capture CO2 from the flue gas of a typical 6.4 MWe power plant. The scaled-up results showed packing height and diameter of absorber to be 5.5 m and 1.5 m; while that of the stripper was 5.08 m and 1.45 m respectively. Effect of flue gas temperature on the capture efficiency was studied, it was observed that as the temperature increased from 20 ºC, the capture efficiency increased, but at 70 ºC, the efficiency showed no significant increase which could be associated with the existence of a temperature bulge. Capture efficiency increases with an increase in PZ concentration due to increase in the rate of reaction with concentration. The absorption and regeneration results suggest that an aqueous MDEA/PZ blend could be a prospective absorbent for CO2 capture.

Experimental Modeling of CO2 Sorption/Desorption Cycle with MDEA/PZ Blend: Kinetics and Regeneration Temperature

CO2 sorption–desorption cycles with a methyldiethanolamine (MDEA)/piperazine (PZ) blend have been performed with a rotoevaporator. Similar to other CO2 separation technologies, the heating involved in MDEA/PZ solvent regeneration is the most energy-intensive step in the overall CO2 separation process. Thus, this study investigated the desorption kinetics under low-pressure (<200 mbar) and low-temperature conditions in the range from 308 to 363 K with the aim of reducing costs. The CO2 desorption time to unload the samples from ~2.35 mol/kg to below the threshold of 1 mol/kg was reduced from 500 s at 333 K to 90 s at 363 K. The Avrami–Erofoyev model was found to fit the experimental kinetic data accurately. The Arrhenius law calculations provided an activation energy of the CO2 desorption process equal to 76.39 kJ/mol. It was demonstrated that the combination of a pressure reduction and the increase in temperature resulted in an enhancement of the desorption kinetics, especially at low temperatures. The combined effect of these two factors resulted in higher desorption kinetics compared to the individual effects of either factor alone. Solvent regeneration at a low temperature was demonstrated to be a valid option when coupled with pressure reduction.

Absorpsi CO2 Pada Wetted Wall Column dengan Variasi Laju Alir NaOH dan Konsentrasi Methyldiethanolamine

This research describes the biogas purification process by reducing CO2 content using NaOH solution as an absorbent and methyldiethanolamine (MDEA) as a promoter in Wetted Wall Column (WWC). The purpose of this study was to determine the effect of MDEA concentration and flow rate of NaOH + MDEA solution on CO2 absorption. The column is made of acrylic material with a diameter of 4.5 cm, height 50 cm, equipped with a tube with a diameter of 1.27 cm, height 45 cm. The tube is in the center of the column. The flow rate of absorbent solution for each run was varied as 150, 200, 250 and 300 ml/min and the concentration of MDEA for each run was 4% wt and 6% wt in 1 M NaOH. The biogas flow rate was 6 L/min, which was fed from the bottom of the column. The samples were analyzed by Gas Chromatography 2014 AT (SHIMADZU Corp 08128). The results showed that at 6% NaOH + MDEA solution, the solution flow rate of 150 mL/min was the best. Under these conditions, the output CO2 content is 13.306% and the output CH4 content is 81.737%. The results of the output CO2 content did not reach the 90% target because the biogas was contaminated by gas from the environment and the lack of control over the condition of the equipment during the absorption process.

Исследование влияния примесей различного характера на пенообразование аминовых абсорбентов установок очистки высокосернистых газов

The article focuses on studying the foaming process in the amine solutions (diethanolamine (DEA) and methyldiethanolamine (MDEA)) on an example of the model mixtures containing different organic and inorganic impurities and their combinations: oxalic acid, formic acid, corrosion inhibitor, hydrocarbons, amine decomposition products, mechanical impurities. It has been found that the greatest influence on foaming in the DEA solution is exerted by its decomposition products containing the formic acid, and at a concentration of 3% by weight the foam height increased by more than 3 times, and the foam stability - by 20 times. Oxalic acid also has a significant effect on foaming: at a concentration of 1 g/l the foam height increased by 3 times, and the foam stability - by more than 5 times. The decomposition products of DEA containing oxalic acid have a rather noticeable effect - the height and stability of the foam increased by 2.8 and 6.8 times, respectively. The foam grew least in the presence of formic acid - by 2 times, at the same time the stability was enhanced by more than 4 times. It has been stated that hydrocarbons have the greatest influence on foaming of the MDEA solution - at a concentration of 0.5% vol. the foam height increased by more than 1.7 times, and the stability of the foam - by 5 times. Similarly, the decomposition products of MDEA made a significant impact – the foam height increased by more than 1.7 times, and the foam stability - by 11 times. Mechanical impurities caused an increase in the foam height by more than 1.6 times and in stability by 1.4 times. Introducing a corrosion inhibitor foaming gave the least result - the foam height decreased by 2.8 times, and the stability increased by 2 times. There has been found the mutual influence of impurities in the MDEA solution, which could be seen in the mutual suppression of foaming in the double and triple mixtures compared with the single-component solutions.

Poly(allylamine)–based amine blends for separation of carbon dioxide in the indoor environment

Amine and polyamine-based materials have been widely cited as solid CO2 sorbents and as catalyst modifiers for CO2 electrochemical reduction, however, lab-scale research into a pilot or industrial-scale application is challenging, beginning with the identification of an effective adsorbent. In this investigation, a membrane with a strong affinity for the adsorption and absorption of carbon dioxide is made by blending small molecular amines and a poly(allylamine) (PAA) solution. The membrane was characterized using Fourier-transform infrared spectroscopy (FTIR) and Scanning Electron Microscope (SEM). The results show that Ethylenediamine (EDA)/Methyldiethanolamine (MDEA) is cross-linked with PAA via hydrogen bonds. We change the proportion of EDA/MDEA with PAA to determine the carbon dioxide separation and selectivity of membranes in ambient air. Results from the separation effectiveness deterioration test for MDEA and PAA, with the same ratio 7 wt% at 200 mbar pressure, show decreased CO2 concentrations of 98 and 35 ppm, respectively.

Energy efficient CO2 capture in dual functionalized ionic liquids and N-methyldiethanolamine solvent blend system at elevated pressures: Interaction mechanism and heat duties

In this study, three lab synthesized dual functionalized ionic liquids (DFILs) were utilized as promoters to improve the CO2 absorption performance of methyl diethanolamine (MDEA) absorbent under elevated pressures of 2–7 bar. Initially, 5 wt% DFILs containing polyamine cations (triethylenetetramine and diethylenetriamine) and cyclic amine anions (piperazine and imidazole) were blended with 20 wt% MDEA and their physical and chemical properties were examined. The pKa value at 303 K of the blend of [TETAH][Pz] + MDEA is found to be 9.83, which is nearly equal to the industrial 30 wt% monoethanolamine (MEA) solution. The CO2 absorption performance at different temperatures and pressures demonstrated that the blending of 5 wt% DFILs into aqueous MDEA significantly altered both the absorption rate and loading. The percentage loading showed a significant 22% increase in the [TETAH][Pz] promoted aqueous MDEA blend. This is attributed to the high amount of carbamate and bicarbonate formation in the DFILs blended aqueous MDEA as revealed by 13C NMR results. These results were possible due to the highly reactive piperazine anion being a crucial factor in the significant performance of the [TETAH][Pz] blend system. Further, when the regeneration heat duty of all these absorbents was calculated, it was found that MDEA and DFILs blended MDEA absorbents consumed 25.36% and 33.34–22.79% less energy than industrial MEA, respectively along with a low absorbent loss during regeneration thus, [TETAH][Pz] and [TETAH][Im] are potential promoters in an aqueous MDEA solvent system for pressurized capture of carbon dioxide.

Evaluation of novel aqueous piperazine-based physical-chemical solutions as biphasic solvents for CO2 capture: Initial absorption rate, equilibrium solubility, phase separation and desorption rate

Novel aqueous piperazine-based physical–chemical solutions were proposed as promising liquid–liquid biphasic solvents for energy-efficient CO2 capture in order to enhance the absorption and desorption performance. Various phase-change systems including Piperazine (PZ), 1-(2-aminoethyl) piperazine (AEP), methyldiethanolamine (MDEA), sulfolane, 1-propanol and water with different concentration ratios were investigated comprehensively in terms of initial absorption rate, equilibrium solubility, phase splitting and desorption rate in the present work. Experimental results indicated that with the aid of organic solvents, PZ and AEP were proved to be promising candidates to accelerate the initial absorption and desorption rates, as well as enhance the CO2 absorption capacity due to their excellent reaction kinetics. The tunable phase separation property could be achieved by varying the concentration ratios of amine/organic solvent. After achieving equilibrium, the two liquid–liquid phases would not return back to one homogeneous liquid phase. Among these biphasic solvents, aqueous 2.5 M PZ + 2.5 M sulfolane with a large CO2 loading 0.85 mol CO2/mol amine at the phase change point was the optimal choice owing to good phase separation and great absorption and desorption properties. Compared to aqueous 2.5 M PZ single solvent, it demonstrated a 16% higher initial absorption rate, 9% larger CO2 absorption capacity and double desorption rate. This research provided a potential alternative absorbent for CO2 capture.

Production of high-purity carbon dioxide and sodium bicarbonate by lime cellar gas cleaning and chemical recycling: Process simulation and techno-economic analysis

The cement industry is responsible for 8% of total global CO2 emissions, which mainly originate from limestone calcination and fuel combustion. In view of the application potential of using CO2 to produce chemicals, this paper developed a novel process based on the Aspen Plus process simulation for the co-production of 99.99% CO2 by means of Methyldiethanolamine (MDEA) absorption/desorption and NaHCO3 by carbonization of CO2, NH3 and Na2SO4. The effects of absorption temperature, NH3 and Na2SO4 feeding amount, crystallizer temperature and pressure on CO2 capture rate and utilization rate were explored. The results showed that the best CO2 capture rate was achieved when the cellar gas inlet temperature of the absorber tower was 37 °C; Saturated Na2SO4 solution was favorable for CO2 absorption, and the CO2 utilization rate increased with the increase of Na2SO4 dosage; NaHCO3 yield decreased with the increase of crystallizing temperature, and the best NaHCO3 yield was achieved when the crystallizer temperature was 35.5 °C; Crystallizing pressure had little impact on the reaction. Economic analysis showed that the project will start to be profitable in 6.48 years with a Net Return Rate (NRR) value of 13.51%. It indicates that the project has economic benefits and provides a new way to reduce CO2 emissions from lime cellar gas.

Towards retrofitting based multi-criteria analysis of an industrial gas sweetening process: Further insights of CO2 emissions

Natural gas processing is currently facing economic and environmental challenges due to abrupt changes in oil prices and the development of an alternate source of energy. Therefore it is essential to optimize the processing unit to make it profitable and environmentally friendly. Sustainable optimization of an industrial natural gas treatment plant is carried out using the NSGA-II algorithm for the methyl diethanol amine (MDEA) process to optimize CO2 removal along with payback period and damage index. This multi-objective optimization study includes seven decision variables such as temperature and pressure of feed gas, feed flow rate, temperature and pressure of regenerator feed, lean amine temperature, and MDEA concentration. Three separate two-objective optimization study problems are developed and applied for retrofitted case and base case studies. Two different ProMax models are developed and validated the model by using actual plant data. All the retrofitted cases and base cases are solved and the Pareto optimal fronts are obtained. Trade-offs between different objectives are illustrated for all the problems. The lean vapor compression process can facilitate maximum H2S removal of 99.75% and maximum CO2 removal of 98.52% simultaneously by maintaining a DI value of 476. TOPSIS method is used to rank and find the best optimal solution. Optimization study for uncertain CO2 concentration (4%mole) in the feed gas is also analyzed and compared with normal feed conditions. The machine learning approach is used to obtain the predictions of selected objective functions for all the problem cases using the decision tree method.

Enhanced CO2 absorption and reduced regeneration energy consumption using modified magnetic NPs

This study aimed to investigate the ability of nanofluids in improving CO2 absorption and reducing regeneration energy demand in a bubble column reactor in the presence of functionalized-magnetic NPs. The first step was to synthesize Fe3O4 nanoparticles (NPs), which were then functionalized with Aspartic-acid and Lysine. Next, to study CO2 absorption and stripping performances, the NPs with different concentrations were dispersed in an aqueous methyl diethanol amine (MDEA) solution (10 wt%). The investigation of CO2 absorption performance, CO2 loading and pH of all nanofluids were reported at different times of absorption experiments. The obtained results indicated that Fe3O4@Aspartic (Fe3O4@Asp) and Fe3O4@Lysine (Fe3O4@Lys) NPs improved CO2 loading up to 15.3% and 21.4%, respectively, as compared to Fe3O4 NPs. In addition, the functionalized-magnetic NPs showed more positive effects on CO2 desorption compared to bare Fe3O4. To show regeneration efficiency, the outlet gas flow rate and its CO2 concentration were measured and the CO2 loading and pH were determined at the end of the desorption experiment. The results revealed that at 70 °C, the CO2 loading was reduced by 58.9% and 55.1% applying Fe3O4@Lys and Fe3O4@Asp, respectively. Therefore, more energy could be saved in desorption process using functionalized magnetic NPs.

CO2 absorption in blended amine solvent: Speciation, equilibrium solubility and excessive property

Mixing different amines is a common method to develop better solvents for CO2 capture. As the mixing provides more adjustability on the solvent properties, it introduces complex interaction between dissimilar amine molecules who may perform diverse role in the reactions. Here we studied CO2 absorption in monoethanolamine (MEA), methyldiethanolamine (MDEA) and their mixtures thereof. The speciation profiles along with CO2 loading were provided via NMR to reveal the competition/coordination of MEA and MDEA in participating the key reactions that drove CO2 absorption (i.e. carbamate formation and amine protonation). Furthermore, the CO2 loading of the solvents were measured under equilibrium for various temperature, CO2 partial pressure. The excessive CO2 loading was firstly introduced to analyze the loading data regarding the solvent composition. Accordingly, an excessive property model was applied for data correlation. The calculated CO2 loading agreed well with experimental data with average absolution relative deviation of 1.7%.

Amino alcohols as recycling-catalysts for degradation of PET to oligoethylene terephthalates

Polyethylene terephthalate (PET) is an essential component of daily life. However, due to PET's resistance to natural degradation, a plethora of life in the ecosystem is swimming in discarded plastic causing a serious environmental disaster. Using glycolysis, a chemical recycling method, PET is largely recycled to bis(2-hydroxyethyl) terephthalate (BHET) monomers. BHET is polymerized back to a pre-polymer (∼25-35 DPn) followed by polycondensation for higher molecular weight PET, hence an energy-intensive and cost-inefficient method. This study demonstrates glycolysis of PET using Amino alcohols (AmOH's) for generating oligoethylene terephthalate (OET) of DPn value of ∼30 in high yields (98%) under mild reaction conditions; 180°C temperature, atmospheric pressure, with recyclability. PET-to-PET cycle was closed by preparing PET from generated OETs. A comparative model study on methyl benzoate (in EG) revealed the efficiency of AmOH's over Hünig's base; N, N-Ethyldiisopropylamine (DIPEA) despite being more basic. Similarly, N-Butyl-N-methylbutane-1-amine (MDBA) demonstrated slower PET conversion than Methyl diethanolamine (MDEA) AmOH. Although AmOH's such as MDEA also act as nucleophile and add to the polymer chain, to our surprise, our NMR studies revealed that there is no sign of insertion of AmOH's indicating that the AmOH's may function as catalysts. Morphological studies conducted under different reaction conditions unveiled the method of OET generation. The computational studies and Kinetic Isotopic studies explained facilitation of hydroxy group of AmOH in the degradation. Following the shrinking core model, the calculated activation energy for degradation was estimated to be 45.4 kJ mol−1.

Influence of Injecting Some Chemicals on MEG Inhibition Performance for Less Recycled MEG

Monoethylene glycol (MEG) is often injected into submarine transportation pipelines, from offshore oil and gas platforms, to suppress hydrate formation. MEG can be recovered, for recycling, through a MEG regeneration plant, onshore. The costs related to hydrate inhibition operations are significant; thus, introducing new methods of reducing the volumes of MEG required by the system potentially will provide significant economic benefits for the operation. The objectives of this study were to evaluate the influence of ammonium hydroxide (NH4OH), sodium hydroxide (NaOH), potassium hydroxide (KOH), and methyl diethanolamine (MDEA) on inhibition performance when separately combined with a MEG 20 wt % solution in a methane gas system. The pH levels applied were 10.96, 10.84, 10.62, and 10.07 for NaOH, KOH, NH4OH, and MDEA, respectively. The results indicated that these compounds suppressed the hydrate dissociation temperatures, to different degrees, when compared with a normal MEG 20 wt % solution. The temperatures were reduced by an average, across the range of pressures, of 0.72, 0.78, and 0.94 °C in the case of MDEA, KOH, and NaOH, respectively. However, when combined with NH4OH, the reduction in dissociation temperature was even more significant, averaging 1.68 °C. An economical assessment of the benefits of reducing the inhibition temperature by this amount, through the combination with NH4OH, indicated an operational cost saving of about 17% within the MEG regeneration process. This level of cost reduction will be of significant interest to the offshore gas-producing industry.

CO2 capture and sequestration from a mixture of direct air and industrial exhaust gases using MDEA/PZ: Optimal design by process integration with organic rankine cycle

Achieving climate change targets requires a massive reduction in carbon dioxide emissions. According to the Paris agreement, this amount should be reached to 30 Gt/year CO2 reduction. Among different energy and environmental technologies, CO2 Capture and Storage (CCS) technologies are promising technologies to achieve those goals. Despite different technical, economical, and environmental CCS challenges, process development based on recent advances can significantly facilitate the CCS’s deployment. This study aims to simulate the absorption system of CO2 with Methyl-Diethanolamine (MDEA) and Piperazine (PZ) absorbents. In this study, three different scenarios have been considered for designing the parts of the absorption tower and air blower that have the highest energy consumption to achieve the highest amount of absorption, purity, and CO2 recovery. Compared results from the defined scenarios show that the use of an intercooler in the middle of the adsorption tower (Scenario 3) is the best design for the CO2 capture simulated process where the adsorption rate is 90.1%, the purity is 82.26 (mol%) and CO2 Recovered reaches 28.74 ton/hr. Since energy consumption in high CO2 absorption rate and purity is one of the main challenges of such technologies, this study also evaluates the combination of the organic Rankin cycle (ORC) with air blowers by three refrigerants R290, R227, and R124 to reduce energy in the carbon capture units. The results show that in this cycle, R290 has the highest power output against R227 and R124 refrigerants under the same conditions. Combining ORC with an air blower reduces the cooling load of the whole process to 104.85 MW and the total power consumption to 46.375 MW. Finally, this study concludes that using different designs and combinations, including ORC cycles in high-energy CCS processes, can also reduce the cost of energy required, and its deployment can help prevent climate change.

High oxygen and SNG injection in blast furnace ironmaking with Power to Gas integration and CO2 recycling

In the last years, reduction of CO2 emissions from the steel industry has been of great importance. Carbon capture, oxygen blast furnaces and top gas recycling technologies, among others, have been deeply studied as low carbon solutions. In this paper, a novel integration of carbon capture and power to gas technologies in the steelmaking industry is presented. Green hydrogen via proton exchange membrane (PEM) electrolysis and CO2 via methyldiethanolamine (MDEA) scrubbing from the blast furnace gas (BFG) are used to produce synthetic natural gas in an isothermal fixed bed methanation plant. The latter gas is injected into the blast furnace, closing a carbon loop and reducing coal consumption. The oxygen by-produced in the electrolyser covers the entire oxygen demand of the steelmaking plant and avoids the need for an air separation unit (ASU). The novelty of this work relies on the variation of the oxygen enrichment and its temperature in the hot blast, and how it influences the power to gas integration concept. This power to gas integration is compared with a conventional BF-BOF plant from a technical, economic, energy and environmental point of view. Both plant process configurations were implemented in Aspen Plus simulations, assessing the fossil fuel demand, energy penalty, cost and CO2 emissions. Emission reduction up to 34% can be achieved with power to gas integration, with an energy penalty of 17 MJ/tHM and a cost of 352 €/tCO2.

Oil extraction & Gas Absorption from Waste Tyre

The article presents research on the purification process of pyrolysis gas from hydrogen sulphide and CO2 which release from waste tyre pyrolysis process. Pyrolysis, a process for treating tyres to create priceless oil, coal, and gas products, is gaining popularity, though. Chemically speaking, the tyre pyrolysis oil is quite complex and contains polar fractions as well as almon, aromatic, and heteroatoms. The fuel properties of tyre oil reveal that it is similar to gas oil or light fuel oil and that it burns successfully in ovens and test engines. The most significant gases created by the pyrolysis of used tyres are CO2, CO2, H2S, and C1-C4 hydrocarbons. revisions to the tyre the updating of higher-grade carbon coal Black and active carbon have been the emphasis of the pyrolysis products on the basis of high value products. It was also claimed that the synthesis of hydrogen from used tyres or converting oil into a chemical food source rich in aromatics involved the employment of catalysts. NaOH in concentration 0.05 M appeared to be the most efficient, showing ∼94% H2S removal efficiency under the conditions studied. To eliminate harmful gases including CO, CO2, and H2S, MDEA (tertiary amine methyl diethanolamine) scrubber gases are released.

Life Cycle Assessment of Post-Combustion CO2 Capture and Recovery by Hydrophobic Polypropylene Cross-Flow Hollow Fiber Membrane Contactors with Activated Methyldiethanolamine

The present study evaluated the environmental impacts of post-combustion CO2 capture and recovery via membrane–gas absorption processes. We have used SimaPro v.9 packages with the Ecoinvent v3.5 database employing two different methods, ReCiPe 2016 Endpoint (H) and Midpoint (H), considering a fundamental methodological framework to determine the most environmentally friendly experimental condition. Life cycle impact categories were examined and assessed supposing a functional unit of 1 kgCO2/h recovered. Fourteen environmental impact categories including global warming, ozone depletion, eutrophication, and toxicity potentials have been evaluated within the context of a gate-to-gate approach focusing on only the process stage. Simulation results showed that the maximum liquid flow rate, sweep helium flow rate together with the minimum solvent concentration demonstrated the highest impact on human health, ecosystem, and resources. The usage of pure methyldiethanolamine (MDEA) activated by piperazine as a reactive absorbent provided the lowest environmental impact due to the elimination of the energy needed to heat and evaporate water present in aqueous absorbent solutions and the prevention of the excess water consumption depending on meeting the water needed for reactive absorption of CO2 in tertiary amine MDEA from simulated humidified flue gas stream. The study highlights the importance of LCA in the determination of an environmentally more sustainable condition during the capture and recovery of post-combustion CO2 by gas absorption and stripping using membrane contactors in tertiary amine MDEA.

Experimental investigation of carbon dioxide absorption by amine-based nanofluids containing two-dimensional hexagonal boron nitride nanostructures

In this research, the influence of the two-dimensional hexagonal boron nitride nanostructures (hBNNs) upon the process of carbon dioxide (CO2) absorption into the aqueous solution of methyl diethanolamine (MDEA) was investigated. The absorption tests were performed using the pressure drop technique in a stirred thermostatic reaction chamber. The hBNNs were synthesized through the sonication-assisted hydrolysis method and characterized by FTIR, XRD, FESEM, EDX, and TGA techniques. After synthesis and characterization, the nanostructures were dispersed in an aqueous MDEA solution at different concentrations via ultrasonication and without surfactants. The stability of the nanodispersions was measured by the zeta potential analysis. The effect of hBNNs loading, MDEA concentration in the base fluid, and amount of nanofluid on the absorption process was also studied. The results revealed that the addition of hBNNs into the base fluids up to a concentration of 0.025 wt% improves the initial CO2 absorption rate and the total amount of absorbed CO2, yet, by further increasing the concentration, the mentioned values are decreased. According to the absorption measurements, for the 5 wt% aqueous solution of MDEA containing 0.025 wt% hBNNs, the highest enhancement of the initial CO2 absorption rate and the total absorbed CO2 into the nanofluid were 5.1 and 3.98%, respectively. The results also indicated that higher MDEA concentrations weaken the enhancement effect of the nanofluids. Furthermore, it was observed that the effect of the nanofluids on the absorption process is independent of their amount. According to the experiments, hBNNs could be reused for at least five consecutive cycles, without a significant drop in the nanofluid efficiency. The results of this study indicated that the use of the two-dimensional hBNNs at very low concentrations improved the CO2 absorption process.