Oxidative degradation of a novel AMP/AEP blend designed for CO2 capture based on partial oxy-combustion technology

Versión aceptada. Embargo 24 mesesSolvent degradation and volatile compound emissions are two of the major concerns about the deployment of carbon capture technologies based on chemical absorption. In this context, partial oxy-combustion might reduce the solvent degradation due to the use of a higher CO2 concentrated flue gas. This work evaluates the oxidative degradation of a novel AMP/AEP blend, namely POS #1, under partial oxy-combustion conditions. The effects of temperature and flue gas composition were evaluated in terms of solvent loss, degradation rates, NH3 emissions and degradation products. The experiments were set at temperatures up to 70 °C and two levels of O2 concentration – 3%v/v and 6%v/v. The CO2 concentration of the flue gas ranged between 15%v/v and 60%v/v CO2. The novel solvent POS#1 showed high resistance to degrade and resulted in lower degradation rates than MEA in all the operating conditions evaluated in this work. The maximum degradation of AEP and AMP was 24% and 19%, respectively. MEA degraded almost double under the same conditions. Temperature and O2 concentration enhanced the oxidative degradation of POS #1. However, the use of higher CO2 concentration in the flue gas led to lower degradation rates of AEP and AMP and hence oxidative degradation was partially inhibited under partial oxy-combustion conditions. The presence of higher CO2 content in the flue gas decreased the NH3 production and a 70% reduction of its emissions was achieved as the CO2 concentration shifted from 15%v/v to 60%v/v. Other major degradation compounds such as formate and 2,4-lutidine were also decreased. New degradation products were not identified so that the suggested degradation pathways proposed in the literature were not influenced by the presence of higher CO2 concentrations.Ministerio de Economia y Competitividad CTM-2014-58573-RUnión Europea, European Development Research Fund (EDRF

Process intensification for post combustion CO₂ capture with chemical absorption: a critical review

The concentration of CO₂ in the atmosphere is increasing rapidly. CO₂ emissions may have an impact on global climate change. Effective CO₂ emission abatement strategies such as carbon capture and storage (CCS) are required to combat this trend. Compared with pre-combustion carbon capture and oxy-fuel carbon capture approaches, post-combustion CO₂ capture (PCC) using solvent process is one of the most mature carbon capture technologies. There are two main barriers for the PCC process using solvent to be commercially deployed: (a) high capital cost; (b) high thermal efficiency penalty due to solvent regeneration. Applying process intensification (PI) technology into PCC with solvent process has the potential to significantly reduce capital costs compared with conventional technology using packed columns. This paper intends to evaluate different PI technologies for their suitability in PCC process. The study shows that rotating packed bed (RPB) absorber/stripper has attracted much interest due to its high mass transfer capability. Currently experimental studies on CO₂ capture using RPB are based on standalone absorber or stripper. Therefore a schematic process flow diagram of intensified PCC process is proposed so as to motivate other researches for possible optimal design, operation and control. To intensify heat transfer in reboiler, spinning disc technology is recommended. To replace cross heat exchanger in conventional PCC (with packed column) process, printed circuit heat exchanger will be preferred. Solvent selection for conventional PCC process has been studied extensively. However, it needs more studies for solvent selection in intensified PCC process. The authors also predicted research challenges in intensified PCC process and potential new breakthrough from different aspects

Physicochemical Properties and Solubility of Piperazine Activated Aqueous Solution of ß-Alanine As A Solvent for CO2 Capture

Carbon dioxide is one of the major greenhouse gas (GHG) contributors. It is an obligation for the industry to reduce the amount of carbon dioxide emission to the atmosphere. Tremendous research and studies are being done in order to develop the most plausible absorber for carbon dioxide removal. Amino acids are being looked into by the industry as a potential solvent for absorption of carbon dioxide to replace alkanolamines due to its ability to resist oxidative degradation, low volatility due to its ionic structure and higher surface tension. In addition, the introduction of promoter-like piperazine to amino acid helps to further enhance the solubility effect by acting as catalyst to speed up absorption process. In this work, the effect of piperazine activated aqueous solutions of B-alanine on physicochemical properties and solubility of CO2 is studied for various correlations. The properties are measured over a wide range of temperature from (30-60) 0C. The effect of activator piperazine on the CO2 loading performance of selected amino acid under high-pressure conditions (1bar to 10bar) at temperature range of (30-60) 0C was studied. From the observations, the density and surface tension of piperazine activated aqueous solutions of B-alanine decreases when the piperazine concentration increases. It was noticed that the density and surface tension decreases with increasing piperazine concentration in the blends. Density, viscosity and refractive index decrease with increasing temperature. Surface tension of piperazine activated aqueous solutions of B-alanine increases with increasing temperature. The value measured for physicochemical properties were correlated as a function of temperature using least-squares method and the correlation parameters are reported together with it respective standard deviation. Solubility of CO2 increases with decreasing temperature and increasing pressure. Quadratic representation of solubility using Response Surface Methodology (RSM) is generated and from the findings, the most important parameter to optimize solubility is system pressure. Addition of piperazine to amino acids solutions can increase the solubility effect of the solvent

Co2 Solubility In Aqueous Blend Diethanolamine (Dea) And Piperazine (Pz) Solution

The solvent blend diethanolamine/piperazine (DEA/PZ) has been investigated as an alternative for CO2 capture from coal fired power plants. Solubility data of carbon dioxide In aqueous mixtures of diethanolamine (DEA) with piperazine (PZ) have been measured at 30oC, 50oC and 70oC and at partial pressures of carbon dioxide between 200 and 1000 kPa. The mixtures of alkanolamlnes studied are 20 wt % DEA, 40 wt % DEA, 20 wt % DEA + 5wt%PZ, 20 wt % DEA + 10wt%PZ, 40 wt % DEA + 5 wt % PZ and 40 wt % DEA + 10 wt % PZ aqueous solutions. The solubility of carbon dioxide in aqueous solutions is reported as functions of partial pressures of carbon dioxide at the temperatures studied. Further physical properties (Refractive Index, density and viscosity) on aqueous blend solution also been done. All of the measured physical property values were correlated as a function of temperature

The characterization and removal of foam promoting impurities from blended methyldiethanolamine - piperazine solution using membrane

The removal of acid gases from natural gas stream is an important process in many gas processing plants and for environmental protection. The most widely used acid gas removal technology nowadays is the absorption process using amine-based solvent. Foaming is the major cause that leads operational problems, resulting in excessive solvent losses, failure to meet treated gas specification and a reduction in gas treating capacity. Therefore, the main objectives of this research were to study the foam characteristics and the surface tension phenomenon of alkanolamines solution and to reduce their foaming promoters. The effect of natural gas impurities (foam promoters) in the blended methyldiethanolamine (MDEA)-piperazine solution such as hydrocarbon liquids, iron sulfide (dissolved solid), sodium chloride (salt), acetic acid (organic acid), methanol (hydrate inhibitor) and glycol (dehydrating agent) were investigated. The concentration of MDEA was found to significantly influence the foam activity in the solution. Iron sulfide, hydrocarbon and sodium chloride present in the solution had been identified as the impurities which apparently contributed to the high foaming tendency. At 5000 ppm concentration of impurities, the foam height achieved was 425 ml. Iron sulfide appeared to be the major foam promoter in the range of concentration solutions studied. Response surface methodology and central composite design had been applied to optimize the three factors that affected the foaming phenomenon. These factors were then correlated to the surface tension and foaming tendency. Asymmetric mixed matrix membrane (MMM) was applied to remove foam promoters in the amine solvent in order to reduce its foaming tendency. The MMM characteristics and performance were tested using scanning electron microscope, differential scanning calorimetry, Fourier transform infrared and membrane filtration tests. The contents of iron sulfide, hydrocarbon and sodium chloride as the main foam promoters had been successfully reduced as indicated by reduction of surface tension values by 12 %, 6.3% and 16 % respectively. These results indicated that membrane is a promising and viable technology to enhance the effectiveness of gas treatment system through the reduction of foam formatio

Solubility of carbon dioxide in aqueous blends of 2-amino-2-methyl-1-propanol and piperazine

In this work, we report new solubility data for carbon dioxide in aqueous blends of 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ). A static-analytical apparatus, validated in previous work, was employed to obtain the results at temperatures of (313.2, 333.2, 373.2, 393.2) K, and at total pressures up to 460 kPa. Two different solvent blends were studied, both having a total amine mass fraction of 30%: (25 mass% AMP+5 mass% PZ) and (20 mass% AMP+10 mass% PZ). Comparisons between these PZ activated aqueous AMP systems and 30 mass% aqueous AMP have been made in terms of their cyclic capacities under typical scrubbing conditions of 313 K in the absorber and 393 K in the stripper. The Kent–Eisenberg model was used to correlate the experimental data

Thermophysical Behavior of Aqueous Blends of Piperazine and Potassium Carbonate as Carbon Dioxide Capture Solvent

This project concerns the thermophysical behavior of aqueous blends of Piperazine (PZ) and Potassium Carbonate as carbon dioxide, capture solvent. The blends of amine solution has the potential to increase the rate of absorption of . The objectives of this project are: (1) to find out the physical properties of PZ to activate potassium carbonate solution in water; (2) to study the effect of temperature change on the physical properties of PZ, potassium carbonate and blends of PZ and potassium carbonate solutions; (3) to study the effect of concentration change on the physical properties of the blends of amines and (5) compare the result with conventional solvent. The scope of study of this project covers the refractive index surface tension for the physical properties of the chemicals solution and also the effect of temperature change and concentration change on the amines. Different set of concentration of PZ and potassium carbonate will be prepared for the blends solution. This experimental based project also will be conducted on the different set of temperatures. Each of potassium carbonate solution will be blended with five different set of percentage (wt%) of PZ and water during the experiment. This experiment will be conducted at different temperatures which are from 293.15K to 323.15K. The result of the experiment will be the refractive index and surface tension for each blends solution. When the data is obtained, further analysis and appropriate discussion will be explained

CO2 Capture Using Amino Acid Salt Solution

The concern of climate change and global warming has consecutively risen to progress research fields pledging to find the possible solutions. Increasing use of fossil fuels leads to an increase in CO2 emission and has become a major task to be deal with. For industrial applications, aqueous solutions of amines are extensively used as chemical absorbent or solvent. However, amine reaction with CO2 results in stable carbamate formation, which in turn leads to high energy usage for regeneration and promote additional corrosion problems. To overcome these restrictions, this study proposes a methodology to analyze the performance of new solvent namely amino acid salt solution. Evaluation of solvent performance in terms of CO2 loading and designing of acid gas removal system, requires pressure solubility data and design properties like density, pH value and refractive index

Semi-empirical model for the direct simulation of power plant with integrated post-combustion CO2 capture processes by wet chemical absorption

AbstractIn this work, a semi-empirical column model is developed to represent post-combustion CO2 capture processes with chemical solvents in coal-fired steam power plants. The solvents are represented by empirical correlations on the basis of fundamental measurement data (CO2 solubility, heat capacity, density). The model of a CO2 capture process including the column model is coupled to detailed models of a hard-coal-fired steam power plant and of a CO2 compressor to evaluate and compare the impact of CO2 capture on the overall power plant process using six different solvents

Extension of a multi-criterion performance indicator model for post combustion Co2 capture using amine solvents.

Masters Degree, University of KwaZulu-Natal, Durban.Energy generation by carbonaceous fuel combustion has been identified as one of the predominant sources of CO2 emissions. Many scientists and researchers believe that rising CO2 levels have an adverse effect on the environment, therefore research on the capture and storage of CO2 is ongoing. Post-combustion capture with amine-scrubbing has been identified as a practical short-term solution to the problem. The alkanolamine, monoethanolamine (MEA) is the current solvent of choice for this application. However, due to disadvantages connected to its use, there is a need to identify alternative superior solvents or solvent blends. A quick and inexpensive method to identify alternative solvents is via process simulation and modelling. These tools enable the assessment of solvent viability on a large scale and the elimination of unsuitable candidates without the expense of extensive laboratory testing. The main units considered in a post-combustion CO2 capture simulation are the absorber, where the amine solvent is used to remove CO2 from a flue gas stream, and the stripper, which enables the separation of the CO2 from the solvent to facilitate recycle of the solvent for re-use in the absorber. User inputs into these simulations include the flow rate and composition of the flue gas to be treated, the solvent composition, and the desired CO2 capture rate. A multi-criterion performance model for the evaluation of solvents used for CO2 capture from a coal-fired power plant, was previously developed by Daya (2017) within the Thermodynamics Research Unit at the University of KwaZulu-Natal. The inputs to this performance indicator model are primarily solvent flow rates and equipment heat duties, which were obtained from ASPEN Plus® simulations. Among the other inputs required are price data for the various factors considered in the model, which include energy requirements, make-up flows and carbon taxes. The solvents investigated to test the performance model’s viability consisted of primary, secondary, tertiary and sterically-hindered alkanolamine solvents and their blends. MEA was used as the basis of comparison. In this study, the performance indicator model is used to evaluate the performance of the previously studied amines, n-methyldiethanolamine (MDEA) and 2-amino-2-methyl-1-propanol (AMP), in different blends as along with an additional component, piperazine (PZ). Different concentrations of the binary blends MDEA+PZ and AMP+PZ as well as the ternary blend, MDEA+AMP+PZ, were investigated. The solvent selected as the basis for the ratings was also changed from 30 wt.% MEA to 30 wt.% AMP, as AMP was previously proven to outperform MEA. The rating for the benchmark case calculated by the performance model formulae, is one. When the same calculations are applied to the other amine blends investigated, ratings below one show a performance inferior ABSTRACT v than the benchmark, whilst a rating above one show better performance compared to the benchmark. Of the blends studied, the solvent with composition 25 wt.% AMP + 5 wt.% PZ + 70 wt.% H2O was the best performing with an overall performance increase of approximately 35% (which corresponds to a rating of 1.359). This solvent was further studied using alternative process configurations: the absorber intercooling (ICA) and rich solvent splitting (RSS) configurations. These configurations have been reported to noticeably reduce the energy requirements for solvent regeneration, with minimum additional equipment. A rating of 1.483 was obtained for the ICA configuration, which is a 9% improvement on the rating of the conventional configuration with the same solvent. The results for the RSS configuration, however, shows no improvement on the performance of the conventional configuration.Only available in English