WO2010134926A1 - Acidic gas capture by diamines - Google Patents
Acidic gas capture by diamines Download PDFInfo
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- WO2010134926A1 WO2010134926A1 PCT/US2009/045075 US2009045075W WO2010134926A1 WO 2010134926 A1 WO2010134926 A1 WO 2010134926A1 US 2009045075 W US2009045075 W US 2009045075W WO 2010134926 A1 WO2010134926 A1 WO 2010134926A1
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- thermally stable
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- stripper
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- stable amine
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/18—Absorbing units; Liquid distributors therefor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1493—Selection of liquid materials for use as absorbents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/30—Sulfur compounds
- B01D2257/304—Hydrogen sulfide
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/30—Sulfur compounds
- B01D2257/306—Organic sulfur compounds, e.g. mercaptans
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/30—Sulfur compounds
- B01D2257/308—Carbonoxysulfide COS
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/50—Carbon oxides
- B01D2257/504—Carbon dioxide
Definitions
- CO is removed from the solvent at 1.5 -2 atm and 90-130 0 C in a countercurrent reboiled stripper with trays or packing.
- Commercially used amines that are used by themselves in water include monoethanolamine, diethanolamine, methyldiethanolamine, diglycolamine, diisopropanolamine, some hindered amines, and others (Kohl and Nielsen (1997)). These amines are soluble or miscible with water at ambient temperature at high concentrations that are used in the process to maximize capacity and reduce sensible heat requirements.
- Other amines, including piperazine are used in combination with methyldiethanolamine and other primary amines.
- Piperazine is a diamine that has previously been studied as a promoter for amine systems to improve kinetics. In water at 25°C, solid piperazine has a solubility less than 2 M, so it cannot be used in traditional systems at
- HOU03 1 2 OO893 3 concentrations that give adequate CO 2 capacity for good energy performance.
- BASF has disclosed the used of piperazine in combination with other amines (such as alkanolamines) or highly water soluble organics (such as triethyleneglycol) to promote the water solubility of piperazine. It has also been claimed that number of potentially useful amines such as piperazine would be too volatile if used in high concentrations in aqueous solvents.
- the boiling point of piperazine (146.5 0 C) is lower that that of monoethanolamine (17O 0 C), so the use of Raoult's law would suggest that it would have a greater volatility at the top of the absorber.
- Figure 1 shows a typical flowsheet for aqueous amine absorption/stripping for CO2 removal.
- Figure 2 shows an exemplary double-matrix stripper configuration.
- Figure 3 shows an exemplary internal exchange stripper configuration.
- Figure 4 shows an exemplary multipressure stripper configuration with a split feed.
- Figure 5 shows an exemplary flashing feed stripper configuration.
- Figure 6 shows an exemplary double-matrix stripper configuration with exemplary operating parameters.
- Figure 7 shows an exemplary internal exchange stripper configuration with exemplary operating parameters.
- Figure 8 shows an exemplary multipressure stripper configuration with a split feed with exemplary operating parameters.
- Figure 9 shows an exemplary flashing feed stripper configuration with exemplary operating parameters.
- Figure 10 shows an exemplary multistage flash stripper configuration.
- Figure 11 shows an exemplary generalized flowsheet for multistage stripping.
- Figure 12 shows an exemplary generalized flowsheet for multistage stripping.
- Figure 13 shows a solid-liquid transition temperature for aqueous PZ.
- Figure 14 shows a comparison of solid solubility for aqueous PZ solutions.
- Figure 16 shows CO 2 solubility in aqueous PZ solutions ranging from 0.9 to 8 m PZ and from 40 to 100 0 C.
- Figure 17 shows a comparison of mass transfer coefficients in 8 m PZ and 7 m MEA from 40 to 100 0 C.
- Figure 18 shows a comparison of PZ and MEA volatility normalized to amine concentration.
- Figure 19 shows and exemplary flowsheet of a three stage flash.
- Figure 20 shows equivalent work for stripping with 5°C approach and rich P * co2 of 5 kPa for 8 m PZ.
- the present disclosure generally relates to compositions, systems, and methods for the removal of acidic gas.
- the present disclosure relates to compositions, systems, and methods for the removal of acidic gas from a gas mixture using a solvent comprising a thermally stable amine (e.g., piperazine) and carbon dioxide.
- Thermally stable amines generally refers to amines that are functional at elevated temperatures.
- thermally stable amines may be stable up to about 130 0 C, 140 0 C, 150 0 C, and 170 0 C.
- thermally stable amines include, but are not limited to, piperazine (PZ) and various substituted piperazines (e.g., methylpiperazine, dimethylpiperazine, ethylpiperazine, and diethylpiperazine), morpholine, 5-amino-l- pentanol, 2-amino-2-methyl-l-propanol (AMP), diglycolamine (DGA®), 4-amino-l-butanol, 3-amino-l-propanol, hydroxy ethylpiperazine (HEP), l-amino-2-propanol, methyldiethanolamine (MDEA), 2-amino-l-propanol.
- PZ piperazine
- various substituted piperazines e.g., methylpiperazine, dimethylpiperazine, ethylpiperazine, and diethylpiperazine
- morpholine e.g., 5-amino-l- pentano
- HOU03 1200893 3 The present disclosure is based in part on the discovery of optimum stripper process configurations and operating conditions that result in unexpectedly high lean loading of CO 2 .
- Such process configurations may include the matrix, internal exchange, flashing feed, multipressure, and stripper processes described herein.
- Such operating conditions may include an unexpectedly low exchanger approach temperature. In some embodiments, such exchanger approach temperatures may be approximately 5 0 C.
- thermally stable amines may be less volatile in an aqueous solution than expected from Raoult's law.
- the activity coefficient of a thermally stable amine e.g., piperazine
- MEA monoethanolamine
- the present disclosure is also based in part on the discovery that when thermally stable amine solutions are loaded with about 0.1 to about 0.6 moles carbon dioxide per amine equivalent, the volatility of the thermally stable amine may be further reduced.
- loading refers to moles CO 2 /mole alkalinity where monoamine have one mole alkalinity per mole of amine and diamines have two moles of alkalinity per mole amine. In certain embodiments, the loading may be 0.25 to 0.45 moles carbon dioxide per amine equivalent. Such a reduction may occur at least in part because of the formation of carbamate ions. Such a reduction may result in the ability to produce concentrated solutions of thermally stable amine loaded with CO 2 which have a volatility acceptable for use in the methods of the present disclosure.
- the present disclosure is also based in part on the discovery that the total solubility of a solid thermally stable amine may be enhanced in solutions loaded with CO 2 .
- the present disclosure provides solutions comprising from about 3 m to about 20 m (moles thermally stable amine/kg water) total thermally stable amine when said solutions are loaded with from about 0.1 to about 0.6 moles CO 2 per amine equivalent. This increase in solubility may be due in part to the formation of carbamate ions.
- solutions comprising from about 4 m to about 12 m (moles thermally stable amine/kg water) total thermally stable amine.
- the solutions are loaded with from about 0.25 to about 0.45 moles CO 2 per amine equivalent.
- the present disclosure is also based in part on the discovery that concentrated aqueous thermally stable amines may be more stable to oxidative and/or thermal degradation as compared to conventional solutions, such as MEA.
- the presence of dissolved iron may catalyze the degradation of MEA at a higher rate than the degradation of thermally stable amine.
- solutions of thermally stable amine loaded with CO 2 may not degrade significantly even at temperatures as high as 150 0 C, whereas MEA may undergo significant degradation (up to about 50%) at 120 0 C.
- the present disclosure provides solutions comprising a thermally stable amine which may be used advantageously at higher pressures and/or temperatures.
- the solutions comprising a thermally stable amine may be used at temperatures less than 175°C. Such an ability to operate at higher pressures and/or temperatures may, among other things, reduce the amount of energy necessary to perform the methods of the present disclosure. In certain embodiments, such a reduction of the amount of energy may range from about 10% to about 30%.
- solutions comprising thermally stable amine may absorb CO 2 at faster rates. In certain embodiments, the use of solutions comprising a thermally stable amine may result in increased in CO 2 absorption rates ranging from about 20% to about 100%. Such increased CO 2 absorption rates may, among other things, enable absorber configurations which require less packing and pressure drop.
- the thermally stable amine may be recovered following absorption of CO 2 .
- such recovery may occur through an evaporation process using a thermal reclaimer.
- the present disclosure provides a method for the removal of acidic gases from a gas mixture comprising contacting the gas mixture with a solvent comprising a thermally stable amine in an amount from about 0.1 to about 0.6 moles carbon dioxide per amine equivalent.
- any acidic gas capable of removal by the methods of the present invention is contemplated by the present disclosure.
- acidic gases may include, but are not limited to, hydrogen sulfide (H 2 S) or carbonyl sulfide (COS), CS 2 , and mercaptans.
- the gas mixture may be any gas mixture comprising CO 2 for which CO 2 removal is desired and which is compatible with (i.e. will not be adversely affected by, or will not
- the gas mixture may comprise any gas mixture produced as the byproduct of a chemical process. Suitable gas mixtures may comprise one or more of natural gas and hydrogen.
- the present disclosure provides several process configurations that may be useful in the methods of the present disclosure.
- the choice of process configuration may depend upon a number of factors, including, but not limited to, the composition of the gas mixture, the desired amount of CO 2 removal, the concentration of thermally stable amine to be used, and resource or environmental considerations.
- One type of process configuration that may be useful in the methods of the present invention is a matrix stripper configuration.
- such a matrix stripper configuration may be a two-stage matrix, such as the configuration shown in Figure 2. In such a two-stage matrix configuration, the temperature change across the stripper may be reduced without the inefficiencies that may be associated with mechanical compression.
- the rich solution from the absorber may be split into two streams.
- the first stream may be sent to the first stripper at a higher pressure, which may result in a slightly superheated feed. Heat may be applied via reboiler steam.
- the lean solution from the first column may be the semirich feed to the middle of the second column, which may operate at a lower pressure.
- the other rich stream may be fed to the top of the second stripper.
- the second column may produce a semilean stream and a lean stream.
- the semilean stream may be crossexchanged with the rich feed to the second column, while the lean solution may be crossexchanged with the rich solution to the first stripper.
- the water vapor from the overhead of the second column may be condensed, and the CO2 may be sent to the first stage of the compression train.
- the water vapor in the overhead from the first column may be condensed, and the CO2 may be sent to the second stage in the compression train.
- the compression work in this configuration may be reduced due at least in part to recovery of a portion of the CO2 at a higher pressure, which may reduce the need for compression downstream.
- the lower pressure column may be set to 160 kPa for normal pressure operations. In certain embodiments, the lower pressure column may be set to 30 kPa for vacuum operations.
- the pressure of the higher-pressure column and the flow into the flash section may be optimized to minimize the total equivalent work of the system. Even though a
- two-stage matrix is described in the present disclosure, a three-stage matrix may also be used with reduced energy requirement.
- multistage flash stripper configuration Another type of process configuration that may be useful in the methods of the present invention is multistage flash stripper configuration.
- such multistage flash strippers may be configured as a multistage flash with a multistage intercooled compressor as illustrated in Figure 3.
- Cold rich solvent from the absorber is heated by cross exchange with hot lean solution from the last stage.
- At stage n rich solution is heated then flashed to a lower pressure (P n ) to release CO 2 with some water vapor.
- the vapor from the flash tank is combined with vapor from the next stage (n+1), intercooled to condense water and compressed to the pressure (P n-1 ) of the previous stage.
- Lean solution from the last stage is returned to the absorber through the cross exchanger.
- the process may be optimized to select a number of stages from 1 to 6, a pressure ratio (P n ZPn+ 1) from stage to stage of 1.2 to 10, and a heat rate at each stage from 0 to 200 kJ/mol CO 2 .
- the temperature of the flash tank may practically vary from 80 to 175 0 C. This configuration will be especially attractive with flash tank temperature from 120 to 17O 0 C when used with thermally stable amines such as piperazine that do not degrade at the elevated temperature.
- the most attractive configuration with concentrated piperazine solution might use 3 stages, each at 140 to 15O 0 C, with the about the same heat rate, and with approximately equal pressure ratios.
- an exchange stripper configuration is an exchange stripper configuration.
- such an exchange stripper configuration may be an internal exchange stripper, such as the configuration shown in Figure 4.
- this configuration integrates the stripping process with heat transfer.
- this configuration may approach the theoretical limit of adding and removing material and energy streams along the entire column. Similar configurations have been described previously by Leites et al. and Mitsubishi.
- this configuration may alleviate the temperature drop across the stripper by exchanging the hot lean solution with the solution in the stripper.
- the configuration may comprise a continuous heat exchange surface, which may allow for countercurrent heat exchange of the hot-lean solution with the solution passing through the stripper.
- a large overall heat transfer capability of 41.84 WZK- mol solvent per segment may be used. Such a heat transfer capability may
- HOU03 1 2 OO893 3 result in a typical ⁇ T of about 1.2 K and about 3 K in the internal exchanger for the vacuum operation, and for operation at normal pressure, respectively.
- a multipressure configuration may be a multipressure configuration with a split feed, such as the configuration shown in Figure 5. Similar multipressure configurations have been described in our previous work.
- this configuration may take a 10% split feed from the liquid flowing from the middle to the lowest pressure level in a multipressure stripper, and it may send this stream to an appropriate point in the absorber.
- the temperatures at the bottom of the stripper pressure sections may be equal, and heat may be added to each stripper pressure section to achieve isothermal operation in each section.
- this configuration may take advantage of the favorable characteristics of the multipressure configuration and the split flow configurations.
- the middle pressure may be configured to be approximately the geometric mean of the top pressure and the bottom pressure.
- FIG. 6 Another type of process configuration that may be useful in the methods of the present invention is a flashing feed configuration.
- this configuration may comprise special configurations of the split flow concept described by Leites et al. and Aroonwilas.
- at least a fraction of the rich stream may be sent to the middle of the stripper, where, after stripping, a lean solution may exit at the bottom.
- the rich solution may be cross- exchanged with the lean solution exiting the stripper bottom.
- the vapor leaving the stripper may then be contacted with the absorber rich flow in a five-staged upper section where the latent heat of water vapor may be used to strip the CO2 in the 'cold feed' and a semilean stream may be produced.
- the semilean product may be cross-exchanged with the rich solution fed to the upper section.
- the reboiler duty may remain substantially unchanged, and 'free stripping' may be achieved in the upper section.
- the split ratio of the rich streams into the middle and upper sections may be optimized to minimize equivalent work.
- HOU03 1200893 3 The choice of operating conditions for each of these process configurations may depend upon a number of factors, including, but not limited to, the composition of the gas mixture, the desired amount of CO 2 removal, the concentration of piperazine to be used, and resource or environmental considerations. Examples of suitable operating conditions are shown in Figures 7, 8, 9, and 10 for the double matrix, internal exchange, multipressure with split feed, and flashing feed stripper configurations, respectively.
- FIG. 11 Another type of process configuration that may be useful in the methods of the present disclosure is a multistage stripper configuration and methods for multistage stripping that may be used at temperatures from about 12O 0 C to about 16O 0 C with thermally stable amines.
- the process and configuration also may be used at lower temperatures.
- An example of such a configuration is shown in Figure 11.
- Figure 11 provides a generalized flowsheet example for such an embodiment.
- rich solution is heated by exchange with hot lean solution.
- the hot lean solution, L 1-1 is preheated with steam or another convenient source of heat.
- the rich solution is then distributed at the top of a gas/liquid contacting section in the stage j stripper, usually a packed column.
- the stripper is reboiled with heat provided by steam or another convenient source to the maximum temperature, T j .
- the hot semilean solution, L is then sent on to stage J+l .
- the vapor from the stripper at pressure, P j is sent to the intercooler of stage J of the compressor.
- the intercooler may be cooled by cooling water or it may serve as a source of useful heat. Because the high temperature stripper produces vapor as hot as 15O 0 C, useful heat can obtained at 150 to 8O 0 C from both the sensible heat and latent heat of water vapor as the stream is cooled.
- the recovered heat could include boiler feedwater preheating.
- the recovered heat could also be used as in multieffect evaporation to heat a similar generalized multistage stripper at a lower temperature, such as 100 to 12O 0 C. Condensed water is separated from the cooled vapor. The CO 2 vapor is compressed to the pressure of the previous stage, Pj -1 .
- stage N the hot lean solution, L N , is cooled in the exchanger before being returned to the absorber.
- elements of the generalized flowsheet described above can be deleted to provide simpler effective flowsheets.
- a useful flowsheet will use a preheater without a reboiler or a reboiler without a preheater.
- One version of a simple two stage heated flash would delete the packing and reboiler in both stages. Both of the stages would operate at the same temperature, from 80 to 16O 0 C.
- the preferred temperature with an amine that is resistant to thermal degradation, such as piperazine, is 130 to 16O 0 C.
- a second version of the two stage heated flash would delete the packing and preheater in both stages.
- the present disclosure provides a multistage stripper configuration and methods for multistage stripping that may be used at temperatures from about 12O 0 C to about 16O 0 C with thermally stable amines with integrated heat recovery useing four compressor stages and two exchangers.
- the process and configuration also may be used at lower temperatures.
- An example of such a configuration is shown in Figure 12.
- In 70 to 90% of the rich solution would be fed to Exchangeri.
- the heated rich solution, L 1 is fed to Preheateri heated by steam to 15O 0 C. Without using packing or reboileri, the solution is flashed in Stripper 1 at 16 atm.
- the semilean solution, L 2 is heated in Preheater 2 to 15O 0 C with steam and flashed without packing or reboiler 2 in Stripper 2 at 8 atm.
- the hot lean solution is returned through Exchangeri to the absorber.
- 10 to 30% of the rich solution from the absorber is fed through Exchanges to Preheater 3 and heated by Heat Recoveryi and/or Heat Recovery 2 to HO 0 C.
- Preheater 3 and Heat Recoveryi may be the same heat exchanger. It is then flashed in Stripper 3 at 4 atm without packing or reboiler 3 .
- the semilean solution from Stripper 3 is fed through Preheater 3 and heated to HO 0 C at 2 atm.
- Preheater 4 is heated by and may be the same heat exchanger as Heat Recoveryi and/or Heat Recovery 2 . Preheater 4 may also use heat from high temperature intercooling of other compressor stages or from other sources such as hot flue gas before the flue gas desulfurization system.
- HOU03 1200893 3 solution is then flashed at 2 atm in Stripper 4 without packing or Reboiler 4 .
- the hot lean solution, L 4 is returned to the absorber through Exchanger ⁇
- Example amines were screened for thermal stability based on loss of all amines after 4 weeks at 135°C with a loading of 0.4 mol CO 2 /mol alkalinity. In this example, and under these conditions, thermally stable amines were those that demonstrated less than 37% degradation.
- Table 1 Thermal degradation screening for loss of all amines.
- MEA Monoethanolamine
- AEP Aminoethylpiperazine
- EDA Ethylenediamine
- DETA Diethylenetriamine
- HEEDA Hydroxyethylethylenediamine
- Concentrated, aqueous piperazine (PZ) was investigated as a novel amine solvent for carbon dioxide (CO 2 ) absorption.
- the CO 2 absorption rate with aqueous PZ is more than double that of 7 m MEA and volatility at 40 0 C ranges from 7 to 20 ppm.
- Thermal degradation is negligible in concentrated PZ solutions up to a temperature of 150 0 C, a significant advantage over MEA systems.
- Oxidative degradation of concentrated PZ solutions is appreciable in the presence of copper (4 mM), but negligible in the presence of chromium (0.6 mM), nickel (0.25 mM), iron (0.25 mM), and vanadium (0.1 mM).
- Initial system modeling suggests that 8 m PZ will use 10 to 20% less energy than 7 m MEA.
- the fast kinetics and low degradation rates suggest that concentrated PZ has the potential to be a preferred solvent for CO 2 capture.
- Aqueous piperazine solutions were created by heating anhydrous piperazine (99% pure, Fluka) with water until the solid crystals melted into a solution.
- the warm solution was transferred to a glass cylinder with a CO 2 gas sparger and the cylinder was placed on a scale. The scale was used to gravimetrically add CO 2 to achieve the desired loading.
- CO 2 loading through total inorganic carbon (TIC).
- concentration of CO 2 in solution was determined by total inorganic carbon analysis (Hilliard, 2008).
- the sample is diluted and then acidified in 30 wt% phosphoric acid to release aqueous CO 2 , carbamate, and bicarbonate species as gaseous CO 2 .
- the CO 2 is carried in a nitrogen stream to an infrared analyzer which detects and records changes in voltage. The resulting voltage peaks are integrated and correlated to CO 2 concentrations using a 1000 ppm inorganic carbon standard made from a mixture of potassium carbonate and potassium bicarbonate.
- CO 2 loading is reported as moles CO 2 per mole alkalinity or moles CO 2 per equivalence of PZ, where two moles of alkalinity per mole PZ is the conversion factor.
- HOU03 1 2 OO893 3 equivalence point represents the addition of two protons to the PZ molecule creating a diprotonated PZ molecule. Additional equivalence points seen prior to 3.9 were not used in the analysis.
- Viscosity measurements Viscosity was measured using a Physica MCR 300 cone and plate rheometer (Anton Paar GmbH, Graz, Austria). The apparatus allows for precise temperature control for measuring viscosity at temperatures ranging from 20 to 70 0 C. To determine viscosity, the angular speed of the top disk (cone) is increased from 100 to 1000 s "1 over a period of 100 seconds and the shear stress exerted by the solution is measured every 10 seconds. Reported viscosities are averages of these 10 individual measurements. Oxidative degradation.
- Oxidative degradation experiments were performed in a low gas flow agitated reactor with 100 mL/min of a saturated 98%/2% O 2 /CO 2 gas mixture fed into the headspace (Sexton, 2008).
- the reactor is a 500-mL jacketed reactor is filled with 350 mL of solvent.
- the jacket contains circulated water maintained at 55°C.
- the reactor is agitated at 1400 rpm to increase the mass transfer of oxygen into the solution.
- the reactor is operated continuously for 3-5 weeks, depending on the experiment. Liquid samples are taken every two days and water is added to maintain the water balance on the reactor contents.
- the liquid samples were analyzed for PZ concentration, CO 2 loading, and degradation products by acid titration, TIC, and cation and anion chromatography, respectively.
- Vapor-liquid equilibrium CO 2 solubility and amine volatility were measured in a batch equilibrium cell with gas recycle through a hot gas FTIR (Hilliard, 2008).
- the cell was a jacketed, glass reactor where temperature is controlled within 1°C.
- the inlet gas is sparged from the bottom of the reactor and there is additional mechanical agitation to enhance mass transfer.
- the gas in the headspace of the reactor is continuously sampled by an FT-IR.
- the gas leaves the reactor and passes through a mist eliminator and into a sample line heated to 180 0 C.
- the heated gas stream is then analyzed by the multi-component FTIR analyzer and recycled to the reactor as the inlet gas stream.
- Thermal degradation Thermal bombs were constructed from V 4 or 3 /8-inch stainless steel tubing with two Swagelok ® end caps (Davis, 2008). Bombs were filled with 2 or 10 mL of PZ solution, sealed, and placed in forced convention ovens at multiple different temperatures. Individual bombs were removed from the ovens each week and the contents were analyzed for degradation products, remaining amine concentration, and CO 2 loading.
- the wetted wall column counter-currently contacts an aqueous piperazine solution with a saturated N 2 /CO 2 stream on the surface of a stainless steel rod with a known surface area (Cullinane and Rochelle, 2006; Dugas, 2008).
- the wetted wall column can either perform absorption or desorption of CO 2 depending on the inlet CO 2 partial pressure of gas phase. By bracketing CO 2 partial pressures that result in absorption and desorption, the equilibrium partial pressure of the solution can be determined.
- the gas flow rate entering the wetted wall column is controlled via mass flow controllers.
- Inlet and outlet CO 2 concentrations are measured by Horiba CO 2 analyzers.
- Equation 1 the calculated CO 2 flux divided by the CO 2 partial pressure driving force provides an overall mass transfer coefficient for the experiment (K G ).
- the gas phase mass transfer coefficient, k g is correlated to experimental conditions and is a strong function of the geometry of the apparatus.
- the liquid film mass transfer coefficient, k g ' quantifies how fast the solution will absorb or desorb CO 2 . Results.
- Solid solubility The solid solubility of PZ was studied over a range of PZ concentration, CO 2 loading, and temperature. Solutions were prepared to cover the desired solution properties and were allowed to equilibrate at each condition with stirring before solubility observations were made.
- the transition temperature of 8 and 10 m PZ solutions over a range of CO 2 loading is shown in Figure 13. The transition temperature is the temperature at which a liquid solution will first precipitate when cooled slowly. The approximate temperature ramp for all transitions was 1°C every 5 minutes.
- the two dashed lines at rich loadings in Figure 13 represent soluble PZ solutions indicating that the solubility envelope extends at least this far.
- the transition temperature of unloaded PZ solutions The transition temperature of unloaded PZ solutions
- HOU03 1 2 OO893 3 ranging from 1.0 to 40 m PZ is shown in Figure 14 (The Dow Chemical Company, 2001; Bishnoi, 2000; Hilliard, 2008).
- Viscosity The viscosity of aqueous PZ solutions has been measured from 0.20 to 0.45 mole CO2 per mole alkalinity, 2 m PZ to 20 m PZ, and 25°C to 60 0 C. The viscosity of 8 and 10 m PZ is compared with other amines in Figure 15 (Huntsman Chemical, 2005; Closmann, 2008). The amine concentration is plotted in units of moles alkalinity per kilogram of water in order to compare mono- and diamines on a similar basis.
- Oxidative degradation Heavy metals are known to catalyze the oxidative degradation of amines (Goff and Rochelle, 2004). The results of oxidative degradation of concentrated PZ in the presence of several dissolved metals are shown in Table 1. The experiments simulated four scenarios: (1) leaching of stainless steel metals (iron, chromium, and nickel), (2) addition of a copper-based corrosion inhibitor, (3) addition of a vanadium-based corrosion inhibitor (low concentration), and (4) addition of a copper-based corrosion inhibitor and proprietary inhibitor "A". Oxidative degradation of concentrated PZ was found to be four times slower than that of MEA in the presence of stainless steel metals (Fe2+, Cr3+, and Ni2+) and a low
- HOU03 1 2 OO893 3 concentration of vanadium As with MEA solutions, PZ was determined to be highly susceptible to oxidative degradation in the presence of Cu2+ (Goff and Rochelle, 2006). The primary degradation products were found to be ethylenediamine (EDA), formate, oxalate, and N-formylpiperazine, the amide of formate and PZ (denoted as Formamide in the table). The N-formylpiperazine concentration was not measured directly, but inferred from formate production through the basic reversal of the N-formylpiperazine formation reaction. Also, as with MEA, Inhibitor "A” was able to vastly reduce this degradation to levels comparable with the stainless steel and vanadium cases (Goff and Rochelle, 2006).
- Thermal degradation was investigated in PZ solutions at slightly above stripper temperature (135°C) and much higher than stripper temperatures (150 0 C and 175°C). The thermal degradation results are shown in Table 2 and are reported as the percent of amine lost per week as compared with the initial amine concentration.
- PZ thermal degradation was determined to be negligible at 135 and 150 0 C as compared to 7 m MEA. At 175°C, PZ thermal degradation was observed as a loss of 32% of the initial PZ in 4 weeks. EDA was observed as a thermal degradation product at 175°C but not at lower temperatures. Addition of 5.0 mM Cu2+/0.1 mM Fe2+, 5.0 mM Cu2+/0.1 mM
- CO2 solubility The measured solubility of CO 2 in 2 m to 8 m PZ solutions ranging from 40 to 100 0 C is in given in Figure 16 and compared to previous studies (Dugas, 2008; Ermatchkov et al, 2006; Hilliard, 2008).
- the regression of the data is the equilibrium partial pressure of CO 2 in terms of temperature, T, in Kelvin, CO 2 loading, ⁇ , in mole CO 2 per mole alkalinity, and the universal gas constant, R, in kJ per mole-K, as shown in Equation 3.
- 8 m PZ provides a working capacity of 0.73 mole per kg (PZ+H 2 O), which is calculated based on a change in the equilibrium CO2 partial pressure from 7.5 kPa (loading of 0.415 mole CO 2 per mole alkalinity) to 0.75 kPa (0.33 mole CO 2 per mole alkalinity).
- the working capacity is 0.43 mole CO 2 per kg (MEA+H 2 0) based on a change in the equilibrium partial pressure of CO2 from 5 kPa (0.53 mole CO 2 per mole alkalinity) to 0.5 kPa (0.45 mole CO 2 per mole alkalinity).
- HOU03:1 2 00893.3 mass transfer coefficient based on a gas side driving force, kg', for 8 m PZ is shown compared to 7 m MEA in Figure 17 for 40, 60, 80, and 100 0 C (Dugas, 2008).
- the rate data at 60, 80 and 100 0 C are plotted as function of the equilibrium partial pressure of CO 2 of the solution at 40 0 C.
- this normalized flux, kg', for 8 m PZ is 2 to 3 times greater than for 7 m MEA.
- the kg' for 8 m PZ and 7 m MEA are 1.98 x 10-6 and 7.66 x 10-7 mol/s-Pa-m2, respectively.
- the normalized volatility of PZ solutions is in the same range as the normalized volatility of MEA solutions. It was anticipated that PZ would have a higher volatility than MEA because the boiling point of PZ, 146°C, is lower than that of MEA, 170 0 C. However, the volatility of both 5 and 8 m PZ is slightly lower at 40 0 C. Modeling of PZ systems demonstrates this effect as a greatly reduced activity coefficient for PZ due to the solution's non-ideality (Hilliard, 2008). At 40 0 C, PZ volatility varies from 7 to 20 ppm at atmospheric pressure.
- thermodynamic model for PZ developed by Hilliard (2008) was modified to represent the new data for concentrated PZ.
- the stripper of a system for CO2 removal was simulated for 8 m PZ and compared with 7 m MEA.
- One set of these simulations included a simple stripper with CO2 compression to 15 MPa (150 atm), a 5°C cold side temperature approach for the cross heat exchanger, and a 10 0 C approach for the reboiler.
- the columns were simulated using the AspenPlus® RateSep tool that calculated heat and mass transfer rates but assumed reactions reached equilibrium. In each simulation, 15 meters of CMR NO-2P packing and an 80% approach to flood were used.
- HOU03 1200893 3 A second set of simulations was performed in AspenPlus® using two and three stage flash configurations.
- the flowsheet for the three stage flash is shown in Figure 19.
- the two stage flash is analogous with one less flash tank.
- hot, rich amine leaving the cross exchanger enters a series of flash tanks that are either heated or adiabatic.
- the figure shows the design used for these simulations, where each stage is shown heated with steam.
- a multistage flash collects CO2 at multiple pressure levels, therefore reducing compression work.
- One option is to use this heat to pre-heat the boiler feed water used in the coal- fired power plant (Gibbins and Crane, 2004).
- the 8 m PZ simple stripper system had a minimum equivalent work of 36.5 kJ per mole CO2.
- the two and three stage flashes using 8 m PZ had minimum equivalent works of 34.1 and 33.8 kJ per mole CO2, respectively.
- HOU03 1200893 3 amounts to a loss of only 0.44% of the original PZ per week.
- the most prevalent degradation products were EDA (1.2 mM/wk), formate (0.9 mM /wk), and N-formyl amides (2.3 mM/wk).
- EDA 1.2 mM/wk
- formate 0.9 mM /wk
- N-formyl amides 2.3 mM/wk
- Concentrated, aqueous solutions of PZ have shown promise for improved solvent performance in absorption/ stripping systems used for CO 2 capture.
- a CO 2 loading of approximately 0.25 mole CO 2 per mole alkalinity is required to maintain a liquid solution without precipitation at room temperature (20 0 C).
- the solubility of PZ at 20 0 C is approximately 14 wt% PZ, or 1.9 m PZ.
- the volatility of 8 m PZ systems was found to be between 7.3 and 20.2 ppm PZ at 40 0 C, which is comparable to 7 m MEA solutions.
- Oxidative degradation of concentrated PZ has been shown to be four times slower than 7 m MEA in the presence of the combination of Fe 2+ /Cr 3+ /Ni 2+ and Fe 2+ AV 4+ .
- oxidative degradation is an issue but can be drastically reduced with the use of Inhibitor "A”.
- Concentrated PZ is resistant to thermal degradation up to 150 0 C but does degrade at 175°C, losing 32% of the PZ over 4 weeks. The resistance of PZ to thermal degradation allows for the possibility of higher pressure strippers to improve energy performance.
- HOU03 1 2 OO893 3 of an 8 m PZ solution is 0.73 mole CO 2 per kg (PZ + H 2 O), nearly double that of 7 m MEA.
- Initial modeling of a simple stripper section indicate that the equivalent work required for stripping of an 8 m PZ solution will be approximately 10-20% lower than that of 7 m MEA.
- the use of a multi-stage flash also has demonstrated advantages for a high temperature operation that is feasible with the thermally stable 8 m PZ solution.
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PCT/US2009/045075 WO2010134926A1 (en) | 2009-05-22 | 2009-05-22 | Acidic gas capture by diamines |
AU2009346379A AU2009346379B2 (en) | 2009-05-22 | 2009-05-22 | Acidic gas capture by diamines |
EP09845037.2A EP2432576A4 (en) | 2009-05-22 | 2009-05-22 | Acidic gas capture by diamines |
CA2765673A CA2765673C (en) | 2009-05-22 | 2009-05-22 | Acidic gas capture by diamines |
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8404900B2 (en) * | 2008-10-28 | 2013-03-26 | Korea Electric Power Corporation | Absorbents for separating acidic gases |
WO2013130997A1 (en) * | 2012-03-02 | 2013-09-06 | Research Triangle Institute | Regenerable solvent mixtures for acid-gas separation |
CN104853830A (en) * | 2012-12-07 | 2015-08-19 | 阿克工程及技术股份公司 | An aqueous co2 absorbent comprising 2-amino-2-methyl-1 -propanol and 3-aminopropanol or 2-amino-2-methyl-1 -propanol and 4- aminobutanol |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4064151A (en) * | 1976-05-17 | 1977-12-20 | United Carbide Corporation | Halosilyl carbamates |
US5492683A (en) | 1992-12-11 | 1996-02-20 | United Technologies Corporation | Regenerable supported amine-polyol sorbent |
US5622681A (en) | 1992-01-21 | 1997-04-22 | The Dow Chemical Company | Dialysis separation of heat stable organic amine salts in an acid gas absorption process |
JP2008056642A (en) | 2006-09-04 | 2008-03-13 | Research Institute Of Innovative Technology For The Earth | Method for producing highly concentrated piperazine-containing aqueous solution and method for recovering carbon dioxide |
-
2009
- 2009-05-22 EP EP09845037.2A patent/EP2432576A4/en not_active Withdrawn
- 2009-05-22 AU AU2009346379A patent/AU2009346379B2/en active Active
- 2009-05-22 WO PCT/US2009/045075 patent/WO2010134926A1/en active Application Filing
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Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4064151A (en) * | 1976-05-17 | 1977-12-20 | United Carbide Corporation | Halosilyl carbamates |
US5622681A (en) | 1992-01-21 | 1997-04-22 | The Dow Chemical Company | Dialysis separation of heat stable organic amine salts in an acid gas absorption process |
US5492683A (en) | 1992-12-11 | 1996-02-20 | United Technologies Corporation | Regenerable supported amine-polyol sorbent |
JP2008056642A (en) | 2006-09-04 | 2008-03-13 | Research Institute Of Innovative Technology For The Earth | Method for producing highly concentrated piperazine-containing aqueous solution and method for recovering carbon dioxide |
Non-Patent Citations (10)
Title |
---|
"Ethyleneamines", August 2001, DOW CHEMICAL COMPANY, pages: 48 |
A. SEXTON: "Catalysts and inhibitors for MEA oxidation", PRESENTATION AT GHGT-9, 2008 |
DIGLYCOLAMINE® AGENT - PRODUCT INFORMATION, DIGLYCOLAMINEE AGENT - PRODUCT INFORMATION, 2005, pages 60 |
F. CLOSMANN: "MDEA/piperazine as a solvent for C02 capture", PRESENTATION AT GHGT-9, 2008 |
J. DAVIS: "Thermal degradation of monoethanolamine at stripper conditions", PRESENTATION AT GHGT-9, 2008 |
J.T. CULLINANE; G.T. ROCHELLE: "Thermodynamics of aqueous potassium carbonate, piperazine, and carbon dioxide", FLUID PHASE EQUILIBRIA., vol. 227, no. 2, 2005, pages 197 - 213, XP004887505, DOI: doi:10.1016/j.fluid.2004.11.011 |
M.D. HILLIARD: "A Predictive Thermodynamic Model for an Aqueous Blend of Potassium Carbonate", PIPERAZINE, AND MONOETHANOLAMINE FOR CARBON DIOXIDE CAPTURE FROM FLUE GAS, 2008 |
R. DUGAS: "Absorption and desorption rates of carbon dioxide with monoethanolamine and piperazine", PRESENTATION AT GHGT-9, 2008 |
S. BISHNOI: "Carbon Dioxide Absorption and Solution Equilibrium in Piperazine Activated Methyldiethanolamine", 2000, THE UNIVERSITY OF TEXAS AT AUSTIN |
See also references of EP2432576A4 |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8404900B2 (en) * | 2008-10-28 | 2013-03-26 | Korea Electric Power Corporation | Absorbents for separating acidic gases |
WO2013130997A1 (en) * | 2012-03-02 | 2013-09-06 | Research Triangle Institute | Regenerable solvent mixtures for acid-gas separation |
US10065148B2 (en) | 2012-03-02 | 2018-09-04 | Research Triangle Institute | Regenerable solvent mixtures for acid-gas separation |
US10960345B2 (en) | 2012-03-02 | 2021-03-30 | Research Triangle Institute | Regenerable solvent mixtures for acid-gas separation |
US11559763B2 (en) | 2012-03-02 | 2023-01-24 | Research Triangle Institute | Regenerable solvent mixtures for acid-gas separation |
CN104853830A (en) * | 2012-12-07 | 2015-08-19 | 阿克工程及技术股份公司 | An aqueous co2 absorbent comprising 2-amino-2-methyl-1 -propanol and 3-aminopropanol or 2-amino-2-methyl-1 -propanol and 4- aminobutanol |
JP2016507355A (en) * | 2012-12-07 | 2016-03-10 | エイカー エンジニアリング アンド テクノロジー エーエス | Aqueous CO2 absorbent comprising 2-amino-2-methyl-1-propanol and 3-aminopropanol or 2-amino-2-methyl-1-propanol and 4-aminobutanol |
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Publication number | Publication date |
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EP2432576A1 (en) | 2012-03-28 |
EP2432576A4 (en) | 2013-04-24 |
CA2765673A1 (en) | 2010-11-25 |
CA2765673C (en) | 2016-07-19 |
AU2009346379B2 (en) | 2015-12-10 |
AU2009346379A1 (en) | 2012-01-19 |
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