Mass Transfer Modelling for Compact Hybrid Membrane-Amine System in Removal of C02 from Natural Gas

The removal of CO2 from natural gas down to the pipeline quality is an important step before the natural gas can be sold to the end users. Typical natural gas treatment's specification requires that the composition of CO2 in the treated gas cannot be more than 2 mole%. Normally amine scrubbing process is extensively used to treat natural gas with low content of CO2. However, this is not efficient in dealing with natural gas with high CO2 content. Therefore, there is a proposal of using hybrid system in sequencing of membrane for bulk CO2 removal followed by amine solution for absorption process. However, there are some disadvantages for the hybrid system such as not applicable in offshore. All the disadvantages of the hybrid system will be overcome if the compact hybrid membrane-absorption column is brought into operation. This system uses the concept in which amine absorption is integrated together with the membrane permeation. The feedgas will flow along the membrane and permeate through the membrane and then will be absorbed into the amine solution. The main objective of this work is to develop a mathematical model for the removal of CO2 from natural gas in compact hybrid membrane amine system. The model has analyzed the permeability of CO2 and methane across membrane followed by absorption of CO2 in amine solution. The effect of various parameters, which consist of concentration of CO2 in feed gas, operating pressure of feed gas, flow rate of amine solution and membrane pore size, towards the permeability and separation factor of the compact hybrid membrane-amine system has been analyzed systematically. The model is developed using MATHCAD version 2000i and Microsoft Excel to represent the mass transfer of CO2 in the compact hybrid membrane-amine system. The performance of membrane separation is determined by the permeability of each component through the membrane and selectivity of the membrane for each component in the mixture. Based on the mathematical model developed, it was found that the permeability of CO2 and methane was independent of the concentration of each component in the feed gas. However, the permeability of CO2 and methane was a strong function of operating pressure at the feed gas and membrane pore size due to the effect of surface diffusion at small pore sizes, but this effect was lost at bigger pore sizes. For amine absorption, the mathematical model showed that the separation factor for removal of C02 from natural gas using compact hybrid membrane-amine system was strongly dependent on concentration of CO2 in the natural gas as well as flow rate of amine solution due to its effect on the rate of absorption. However, operating pressure of feed gas does not show any effect on the separation factor of CO2 removal. The model for compact hybrid membrane-amine absorption system is successfully developed and various operating parameters have been studied and discussed in the later section of this report

Heat Integration Study on Cryogenic and Product Recovery Unit of Gas Processing Plant

The production and consumption of natural gas is on the rise throughout the world as the result of its wide availability, ease of transportation and use as well as clean burning characteristics. The first and second generation gas processing plants, designed and built in the 1960s and 1970s were bogged down by operational inflexibility and CO2 freezing due to the rapid change of product values. Even most modern gas processing plants are encountering problems related to operating flexibility, instability of operational conditions due to vapor-liquid equilibrium, CO2 solid formation and energy efficiency. Ortloff have recently developed new NGL recovery processes on the basis of vapor-split concept. While the Ortloff processes offer relief to the first three problems in gas processing plants, huge energy consumption remains a major concern. A typical gas processing plant consists of two main processing sections, i. e. a cryogenic section and product recovery section. Of the two sections, cryogenic section consumes a huge amount of energy, especially by its cold utility due to the sub-ambient operating condition required. Meanwhile, steam generation for reboiling purposes at the product recovery section also contributes to the huge energy consumption. Ultimately, both result in substantial utility cost to the plant operations; therefore optimizing energy consumption in both areas is essential to improving plant profitability as it results in lower utility cost. This research looks for improvement opportunities in energy consumption in these two sections based on pinch analysis and maximizing the power generated from turboexpander. The study explores the utilization of available cold energy extracted from the feed in order to reduce the cold utility requirement in cryogenic area. The study is able to save 6% on refrigeration load for cryogenic area and generate 36% more power from the turbo expander. This could generate predicted annual savings of RM900k for this area. For product recovery area, this study introduces a prefractionator arrangement in place of a conventional depropansier and debutanizer arrangement. Although thermal coupling arrangement requires refrigeration for condenser cooling, nevertheless it generates 54% savings on steam consumption and 37% savings on cooling duty. This is equivalent to RM 2.9mil as predicted annual savings for the plant. Moreover, there are some loose end heat exchangers that could give about RM350k savings per annum for operating cost

An empirical study on factors influencing consumer impulsive purchase behavior: a case of Ho Chi Minh city in the 4.0 era

The fourth industrial revolution (the 4.0 era) has provided companies with more opportunities to attract potential clients across technology-based platforms, thus, bringing new factors that offer a tremendous incentive to buy impulsively, namely Contextual Targeting. Nevertheless, far too little attention has lately been paid to impulse buying behavior in Vietnam. This study offers a comprehensive view on how impulsive behavior is produced, analyzes factors having considerable significance to the impulsiveness, and proposes tactics businesses may use to maximize their sales. The data for this study were selected randomly from the population of Ho Chi Minh city via a survey in the second half of February 2020. From Exploratory Factors Analysis and Multiple Regression Analysis, results reveal that contextual targeting of advertising, packaging, and moods are strongly linked to impulse buying behaviors of Vietnamese consumers, especially in Ho Chi Minh city in the 4.0 era. The study proposes appropriate tactics for businesses to employ as a cheat-sheet, which helps manipulate customer mannerism to maximize profits

The causal relationships between components of customer-based brand equity for a destination: Evidence from South Korean tourists in Danang city, Vietnam

The main purpose of this study is to examine the causal relationships between components of customer-based brand equity for a tourist destination. We have collected data from 252 South Korean tourists in Danang City and tested some hypotheses by applying structural equation modeling (SEM). Results show that: (1) destination brand awareness has a significant and positive effect on destination brand image, but not on destination perceived quality and destination brand loyalty; (2) destination brand image has positive and direct influences on destination perceived quality and destination brand loyalty; and (3) destination perceived quality has significant positive impacts on destination brand loyalty. Lastly, these findings have managerial implications for decision makers

An investigation of the academic consulting competence of high school teachers in Vietnam

High school students must grapple with a host of issues and encounter difficulties when studying at schools, such as peer pressure, test anxiety, cyberbullying, unhealthy relationships, psychological distress, depression and possibly domestic issues. These obstacles create the need for academic consulting in order for high school students to develop essential skills and then solve problems. This study aims to examine the high school teachers' perceptions and the quality of academic consulting competence in the Vietnamese educational context. This study surveyed 1089 high school students and 289 teachers in Ha Noi and Ho Chi Minh City in Vietnam with the 43-item questionnaire. The main results showed that academic consulting competence had been noticed and trained professionally for high school teachers. Additionally, both students and high school teachers recognized the essential role of high school teachers' academic consulting competence in educational settings

Using learning games for fourth-grade students to teach Vietnamese lessons and teachers' perspectives on learning games

Students can learn   in   a   meaningful way through the use of educational games. When students apply their skills and information in order to progress through a game, a huge degree of engagement is generated among them in the classroom as a result both their capabilities and their learning   increase. 153 children from primary schools in Vietnam participated in this research. The children were split into two groups: an experimental and a control group. Both groups participated in two sessions of word and sentence practice as well as spelling instruction. According to the findings of the study, the educational outcomes of the students are greatly improved when games are used in their classrooms. In addition, research has shown that some teachers are against the use of games in the classroom since it makes it more difficult to prepare educational materials. Some educators believe that playing educational games is a more effective method of instruction as it allows for greater flexibility during the learning process. This makes a contribution to the theoretical framework that is necessary to guide educators and instructors in the process of improving learning game programs for children in primary schools and other learners