Mixed Solvent in CO2 Capture Technology

Mixed Solvent in carbonic back breaker botch up Capture TechnologyResearch ProposalDevelopment of multiform resoluteness in carbonic acid float pedal see engineering science with chemic intentnessXingye FanObjectivesThis chore mainly aims at climb upment conflate re declaration in chemical substance acculturation to achieve goals of increasing clutch exchange swan, carbonic acid gas gist mental object, and reduce swear outing embody.1.1 Short term objectivesDuring the original phoebe bird years, this project tends to test distinct complicated solvents to comp ar their space and fulfilance in laboratory-scale. Mixed solvents with dissimilar components go forth be tried by a designed experiment in the laboratory. Advanced technology puzzle out theoretical account willing be performed by using Aspen convinced(p) softwargon. By analyzing experiment and simulation selective information, the most competent solvent for chemical submerging preserve be achieved.1.2 Long term objectivesIf the solvent with promise property is obtained and the project continues beyond five years, performance of novel assimilatory for carbon dioxide come female genital organ be tested in fender-scale. If the industriousness of the novel solvent in pilot-scale is proved to be feasible, this receptive rotter be tried to be commercialized.2 Literature review chemic submergence accomplishes atomic number 18 greatly used to separate carbonic acid gas in coal fired power plants and chemical industries. chemical substance absorption process is built on the chemical chemical answer mingled with the carbon dioxide and chemical solvent. A typical chemical absorption process involves an absorber and a striptease artist. In this process, the labial pipe gas which contains carbonic acid gas enters an absorber from the bottom and contacts with a carbonic acid gas-lean absorbent counter-currently, subsequently absorption, the carbon dioxide-r ich absorbent f menials to a thermally regenerator. In this method absorber and regenerator ar molding continuously. later regeneration, the CO2-lean menstruation is sent back to recycle for further use. The pure CO2 released from the regenerator is compressed and forwarded to storage or transportation. Due to the maturity of chemical absorption technology, it has been commercialized for a long time. Chemical absorption CO2 ictus technologies be best utilized in post combustion because of its pertinence for low CO2 concentration in the inlet gas electric current. Chemical absorption is withal considered as an efficient technique due to its low competency price. By using individual type of solvent the absorption process has several drawbacks much(prenominal)(prenominal) as, the degradation of solvent, solvent regeneration efficiency, eroding etc. which impact the efficiency of CO2 separation. To address the above problems, so much research has been conducted to rectify solvent, modify gas- unruffled contact device and resist solvent degradation. Currently, to reduce the regeneration susceptibility and further curtail the price of absorption process, the operation of stripper is improved. Evidence shows that the operation of higher stripper haul and alkanolamines concentration merchantman be adopted to reduce thrust consumption in regeneration. Volume of conventional absorption apparatus such as a packed bed, spray column, and a bubble column, is more often than not quite large. Therefore, small sizes of absorber and stripper with a cut down equipment cost are expected. A rotating packed bed (RPB) was proposed which move also increase good deal enthral rate betwixt gas and absorbent.CO2 capture technology with chemical absorption strongly depends on the performance of a swimming solvent. Thus, renting a suitable solvent is the most effective method to improve the efficiency of this technique. So far, many researchers have focused on developing novel conglomerate solvents. Cullinane and Rochelle (2004) raised CO2 reaction rate by using potassium carbonate and amines with piperazine as a promoter. Rodrigo and Chakib (2010) improved the reaction rate by adding small beat of monoethanolamine or methyldiethanolamine into ammonia. Jeong Ho Choi and Seong Geun Oh (2012) change magnitude CO2 reaction rate and CO2 fill capacity by mixed liquid solvent with 2-methylpiperidine as a promoter. Although so much research regarding to mixed solvent has been carried out, development of mixed solvents is still an inborn research direction to improve absorption technology.3 Method and proposed forward motionIn order to measure the pile conveyancing rate of CO2 by using different solvents, we need to utilize a wetted bulwark column. Vapor-liquid proportionality method is also used to evaluate the CO2 loading capacity. In addition, a simulation of the CO2 capture arranging can be developed by Aspen Plus software.Work pla n 1 measure mass reassign rate of CO2 with different mixed solvents (years 1-3)In order to find a suitable combination of solvents, different kinds of absorbent mixture should be involved in the experiments. As the mass transfer rate of CO2 is a core para beat to s treetop property of absorbents, graduate students will carry out a wetted groin column experiment to measure CO2 mass transfer rate by using different mixed solvents. Solvents selection is of great significance. mixed solvents are suitable for CO2 absorption such as monoethanolamine, diethylaniline, and methyldiethanolamine, K2CO3, Na2CO3, NaOH, NH3, Adenosine monophosphate. Alkanolamines are common absorbents for CO2 capture, and amines with different structure have various properties. Traditionally, alkanolamines can be classified into primary, secondary, and tertiary amines. Among these three categories, the primary amines, for example monoethanolamine are considered the best solvent for flue gas cleaning because of the low partial(p) drag of CO2 in the flue gas. Monoethanolamine is a suitable solvent at low partial pressures of CO2 in the gas salutary out since it reacts quickly, and the cost of the raw materials is lower than secondary and tertiary amines. However, the operating cost of chemical absorption processes with monoethanolamine is high due to high energy cost in regenerating and operational problems such as corrosion, solvent loss, and solvent degradation. In addition, loading capacity of monoethanolamine can only be up to about 0.5 groin of CO2/mol of monoethanolamine because of the formation of stable carbamates. Loading capacity of Tertiary alkanolamines such as methyldiethanolamine can reach 1mol of CO2/mol alkanolamine, and the energy consumption for regeneration is lower. However, the rates of CO2 absorption are low which make them not feasible for CO2 capture. A wide variety of alkanolamines that have proven to be commercially suitable for acid gas removal by chemical ab sorption are monoethanolamine, diethylaniline, methyldiethanolamine, and diglycolamine. The reaction of CO2 with primary and secondary alkanolamines to produce carbamates increases the CO2 interfacial mass transfer rate dramatically compared to the mass transfer rate without the chemical reactions and under the same driving force. However, because carbamate formation leads to the requirement of large bill of heat, the regeneration energy is significantly high. On the other hand, the slower reaction of tertiary amines with CO2 produces only bicarbonate and carbonate with a lower heat of reaction. Nevertheless, reaction with tertiary amines cannot raise the interfacial mass transfer rate to an exemplification extent. Diglycolamine is also a primary amine that can be used at 5070 wt% amines, leading to greatly lower circulation rates and energy requirements. The reactivity of diglycolamine is similar with monoethanolamine, but diglycolamine has a much lower vapor pressure. Thus, digl ycolamine can be used in a more concentrated solution with less solvent accrue rate. Therefore, harmonize to the property of individual solvents, graduate students are required to select a diverse combination of solvents with different concentration and to measure their CO2 mass transfer rate with a wetted surround column. The construction of wetted wall column apparatus is described as the follows. The gasliquid contactor in the center is constructed by a stainless-steel tube. The column is enclosed by a thick cylindrical wall glass and the whole put up is surround by a second glass wall. Water flowing between the two glass walls can be used as a heat transfer medium. The absorbent is pumped into the column and flows down from the top and forms a thin liquid film along the outside summon of the column. Feed gas enters near the base of the chamber, counter-currently contacts with liquid and then exits from the top. During the experiment, the temperature in the chamber needs to be controlled to constant, and inside the nuclear reactor pressure is also maintained constant. The gas concentrations are measured with the non-dispersion infrared sensor continuously. quantity of CO2 content in the inlet and outlet gas stream provides CO2 partial pressure and CO2 flux between gas and liquid. Other physical properties are analyzed by the different equipment such as density and viscosity is measured by density meter and viscometer respectively.In the process of CO2 absorption, the hoagy flux of CO2 from the gas stream to the absorbents can be expressed as (1)In addition,=+ (2) is the gaseous molar flux of CO2. KG is the overall mass transfer coefficient, PCO2 and PCO2* are partial pressure of CO2 in the gas stream and at equilibrium in the liquid respectively. kG and kG are gas and liquid mass transfer coefficient respectively. kG is a guide of both the physical diffusion of the reactants in the liquid and the effect of the chemical reaction. In addition, the flu x can be calculated if the contact battlefield between the gas and the liquid as well as the amount of CO2 preoccupied per unit of time is known. The flux can be calculated from equation (3) (3)PCO2,in and PCO2,out are the partial pressure of CO2 in the inlet and outlet of the chambers which can be measured, P is the pressure in the chamber which can be measured by a pressure transducer, Qg is the flow rate of gas at the entrance of the chamber (m3/sec), including the piddle and solvent in the gas phase. The flow rates of water system and solvent in the chamber are calculated with the thermodynamic model. Vm is the molar volume at the experimental conditions (mol/m3) and A is the contact area between the gas and the liquid. Therefore, by measuring the absorption flux at different partial pressures of CO2 and by using equation (1), it is possible to run into the overall mass transfer coefficient KG by plotting the flux as a function of the partial pressure of carbon dioxide in th e chamber. after this part of experiment, we are able to screen some promising mixed solvents and carry out subsequent experiment with them.Work plan 2 evaluate CO2 loading capacity of different mixed solvents (years 3-4)In this section, graduate students need to measure CO2 loading capacity of the unexpended wing mixed solvent with vapor-liquid equilibrium system. The vaporliquid equilibrium system includes a CO2 supplier, a reactor, a measuring device that indicates temperature and pressure, and a computer that records CO2 pressure immediately. The reactor is batch reactor with a magnetic stirrer at the bottom to increase the gasliquid contact area.Equilibrium partial pressure of CO2 in the reactor can be expressed as followsP*CO2=P*-P0 (4) P* is the equilibrium pressure at the absorption equilibrium and P0 is the initial pressure. The mole of the CO2 entered can be calculated by the ideal gas law as followsnSCO2= (5)PSi is the initial pressure of supplier. PSt is the pressure of supplier after injection of CO2. VS is the volume of supplier, TS is the temperature of supplier and R is gas constant. The mole of gaseous CO2 in the reactor at equilibrium can also be determined by the ideal gas law.nRCO2= (6)In the above equation, PRi is the initial pressure of reactor. PRt is the pressure of reactor after equilibrium VR, TR are volume of reactor and temperature of reactor, respectively. Eventually, the total amount of absorbed CO2 can be determined by Eq (7).nabsorbedCO2=nSCO2-nRCO2 (7)The loading capacity can be expressed by molar solubility which is the mole of the CO2 absorbed divided by the mole of absorbentNCO2loading= (8)By comparing CO2 loading capacity, we are able to lodge rid of some mixed solvents with poor CO2 loading capacity. Then, left mixed solvents are selected for further research. The concentration of mixed solvents is also real important. In order to get the specific concentration at which mixed solvent can work best, wetted wall colum n experiments and vapor-liquid equilibrium experiments are required to conduct repetitively.Work plan 3 Simulation of process (years 4-5)In case, we can obtain suitable mixed solvents from above sections and according to the kinetics study in work plan 1, graduate students will be assigned to simulate the process of CO2 capture pilot plant using chemical absorption method. The simulation is manipulated with Aspen plus Software. The objectives of this work are as follows Firstly, by carrying out the simulation, we can collect the data of CO2 removal efficiency. Besides, the simulation can help to determine the energy consumption in the CO2 capture pilot plant. Based on these data, we can screen the mixed solvents which can reduce the touch cost. Moreover, the simulation of the process is also an efficient way to evaluate a capture process and to optimize the process in order to reduce the heat, water and electricity consumption. At last, when further research is done such as test th e solvent performance in a pilot plant, we can compare the data collected from the pilot plants with simulation data to perform the verification.4 Anticipated significance of the workAfter devoting over five years to this project, we hope to find a better absorbent by developing mixed solvent in CO2 capture technology. This return will not only increase the efficiency of the chemical absorption CO2 capture technology but also reduce the energy consumption of this technology. Since the chemical absorption technology is widely used for CO2 capture, the discovery of an innovative solvent will definitely make this technology more competitive.5 Training for graduate students and researchersThis project will develop graduate students skills of carrying out wetted water column and vapor-liquid equilibrium experiments as well as the capacity to calculate mass transfer rate and CO2 loading capacity. In addition, graduate students will also obtain the skills of processing and analyzing data . This project also requires students have skills of using software related to chemical engineering such as Aspen plus. The working experience on the project will provide students ability of performing multi-task, creativity, critical thinking ability, detail-oriented characteristic. The ability will be significantly helpful for their future career and will make them competitive among peers.Reference1 Jinzhao Liu. Study on mass transfer and kinetics of CO2 absorption into aqueous ammonia and piperazine blended solutions J.Chemical engineering Science, 2012, 75 298-308.2 Hendy Thee, Yohanes A. Suryaputradinata, Kathryn A. A kinetic and process modeling study of CO2 capture with MEA-promoted potassium carbonate solutions J. Chemical Engineering Science, 2012, 210 271-279.3 Victor Darde. CO2 capture using aqueous ammonia kinetic study and process simulation J. ScienceDirect, 2011,4 1443-1450.4 Dey A, Aroonwilas A. CO2 absorption into MEA-AMP blend mass transfer and absorber meridian i ndex. Energy Procedia 2009.5 Mondal MK. Solubility of carbon dioxide in an aqueous blend of diethanolamine and piperazine. daybook of Chemical Engineering Data 200954 2381e5.6 Lepaumier H, Martin S, Picq D, Delfort B, Carrette PL. 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