چكيده به لاتين
One of the most widely used methods to capture CO2 gas is chemical absorption by amine solvents. Given the high cost of these solvents, it seems necessary to find solutions to improve their absorption capacity. The purpose of this project is to improve the absorption process of CO2 gas through nano and ultrasound technologies. In the first step, amine-based nanofluids were prepared, and their performance was investigated without ultrasonic radiation. For this purpose, four types of nanofluids containing hexagonal boron nitride nanostructures (hBNNs), SiO2, ZnO, and graphene oxide (GO) were synthesized, and absorption tests were performed in a batch system. Results showed that ZnO nanofluids have better performance compared to other nanofluids. In the next step, the effect of simultaneous application of nanoparticles and ultrasound waves on the absorption process was studied in a batch system. Based on the results of the design of experiments method, among the different parameters, ultrasonic power has the greatest effect on the absorption process. Also, RSM optimization showed that the best model to describe the process behavior is the quadratic model. A polynomial relation was presented in terms of factors affecting the process. Then, the optimal value of the parameters was determined to achieve the maximum absorption rate. According to the findings, using ultrasound wave irradiation with a low power of 3.9 watts, the mean absorption rate increased significantly by 632%. After investigating the effective factors and optimizing the process, the effect of the nanoparticle type on the process was investigated using different nanoparticles including ZnO, hBNNs and SiO2. The results indicated the positive effect of SiO2 nanoparticles on the ultrasound-assisted absorption process. However, this positive effect was small compared to the positive effect of ultrasound waves. After studying the effect of the nanoparticle type, the influence of the amine type was investigated. According to the results, among different nanofluids, the highest enhancement in the ultrasound-assisted absorption rate by nanoparticles was observed for MEA-based nanofluids. In the final step, the absorption process was studied in the simultaneous presence of nanofluid and ultrasonic waves in a continuous system. For this purpose, a continuous absorption measurement device was designed. The results showed that, unlike the batch process, the simultaneous application of ultrasound waves and nanofluid in the continuous process causes a significant improvement in the absorption process. This can be due to the intensification of the bubble breakage mechanism in the presence of ultrasound waves, the facilitation of the movement of nanoparticles in the liquid phase due to continuous streams, and the weakening of the effect of ultrasound waves against the effect of nanoparticles in the continuous system. Based on the results, by using the simultaneous application of ultrasound waves and SiO2 nanofluid, the performance of a simple continuous amine absorption system (without the presence of nanoparticles and application of ultrasound waves) is improved by 224.7%, which is a significant enhancement compared to the single application of ultrasound waves (146.9%). The results of this research show that the simultaneous use of ultrasonic waves and nanofluids can be an effective method to improve CO2 absorption.
