78 research outputs found
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
Mass transfer modeling for compact hybrid membrane-amine system in removal of CO2 form natural gas/ By Nguyen, Thi Quynh Nga, TN 880 .N576 2005
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
Heat integration study on cryogenic and product recovery unit of gas processing plant / by Nguyen Thi Quynh Nga, TP 350 .N576 2007
Heat integration study on cryogenic and product recovery unit of gas processing plant / by Nguyen Thi Quynh Nga, TP 350 .N576 2007
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
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