• Clean Technology
• /
• v.18 no.4
• /
• pp.347-354
• /
• 2012

In this study, simulation works have been performed for the $CO_2$ removal process contained in the DME production process using NMP (N-methyl-2-pyrrolidone) as a solvent. PRO/II with PROVISION release 9.1 at Invensys was used as a chemical process simulator and NRTL activity coefficient model with Henry's law option and Soave-Redlich-Kwong equation of state were used for thermodynamic models. For the determination of the binary interaction parameters in NRTL model, regression works have been performed to match the experimental thermodynamic data. Optimal feed tray location which minimizes the reboiler heat duty was determined.

• Clean Technology
• /
• v.22 no.4
• /
• pp.241-249
• /
• 2016

In this study, comparative work has been performed between two-columns and three-columns configurations for an extractive distillation process to produce highly purified ethanol with not less than 99.7 wt% using dimethyl sulfoxide (DMSO) and ethylene glycol (EG) as extracting agents. Optimal ethanol concentration at a concentrator top stream which minimized the total reboiler heat duties was determined for a three-columns configuration for two different solvents. For the thermodynamic model, NRTL liquid activity coefficient model was used and PRO/II with PROVISION 9.4 at Schneider electric company was utilized. DMSO was proved to be a better solvent than EG and three-columns configuration is better than two- columns configuration in the total utility consumptions since some of the liquid water contained in the feed stream was removed at a concentrator bottom liquid stream.

• Clean Technology
• /
• v.17 no.2
• /
• pp.156-165
• /
• 2011

The process for bioethanol production from lignocellulosic biomass was studied through process simulation using PRO/II. Process integration was conducted with concentrated acid pretreatment, hydrolysis process, SMB (simulated moving bed chromatography) process and pervaporation process. Energy consumption could be minimized by the heat recovery process. In addition, material and energy balance were calculated based on the results from the simulation and literature data. A net production yield of 4.07 kg-biomass and energy consumption value of 3,572 kcal per 1 kg ethanol were calculated, which is indicating that 26% yield increase and 30% energy saving compared to the bioethanol production process with dilute-acid hydrolysis (SRI report). In order to make it possible, sugar conversion yield of cellulose and hemi-cellulose is to be reached up to 90% and fermentation of xylose needs to be developed. In order to reduce the energy consumption up to 30%, the concentration of acid solution after being separated by 5MB should exceed 20%. If acid/sugar separation by SMB process is to be practical, the bioethanol process designed in this study can be commercially feasible.

• Applied Chemistry for Engineering
• /
• v.31 no.2
• /
• pp.153-163
• /
• 2020

Compared to gaeous hydrogen, liquid hydrogen has approximately 1/800 volume, 800 times higher volumetric energy density at the same pressure, and the advantage of lower explosion risk and easier transportation than gaseous hydrogen. However, hydrogen liquefaction requires larger scale facility investment than simple compression storage method. Therefore, the research on energy-saving hydrogen liquefaction processes is highly necessary. In this study, helium/neon (mole ratio 80 : 20) refrigeration cycle was investigated as the main refrigeration process for hydrogen liquefaction. Process simulation for less energy consumption were carried out using PRO/II with PROVISION V10.2 of AVEVA. For hydrogen liquefaction, energy consumption was compared in three cases: Using a helium/neon refrigerant cycle, a SMR+helium/neon refrigerant cycle, and a C3-MR+helium/neon refrigerant cycle. As a result, the total power consumptions of compressors required to liquefy 1 kg of hydrogen are 16.3, 7.03 and 6.64 kWh, respectively. Therefore, it can be deduced that energy usage is greatly reduced in the hydrogen liquefaction process when the pre-cooling is performed using the SMR process or the C3MR process, which have already been commercialized, rather than using only the helium/neon refrigeration cycle for the hydrogen liquefaction process.

• Korean Journal of Metals and Materials
• /
• v.50 no.7
• /
• pp.531-538
• /
• 2012

In this study, we evaluated the fluidity of the Al-Zn based alloys which exhibit excellent mechanical properties. We conducted computer simulations of fluid flow using the results of DSC, DTA analysis and Java-based Materials Properties software (J. Mat. Pro). Such computer simulations were then compared with the results obtained from experimental observations. The computer simulation results and the experimental results were very similar in fluidity length. It was found that the fluidity length of Al-Zn alloys is improved by increasing the Zn content while decreasing the solidus temperature of an alloy. In addition, we elucidate the effect of Zn addition on variations in different mechanical properties and the microstructure characteristics of (Al-xZn3Cu0.4Si0.3Fe) x=20, 30, 40, and 45 wt% alloys fabricated by gravity casting.

• Transactions of the Korean hydrogen and new energy society
• /
• v.30 no.4
• /
• pp.297-302
• /
• 2019

In this paper, the power generation efficiency increase has been studied for a Rankine cycle using both supercritical carbon dioxide as a working fluid and LNG as a coolant with PRO/II with PROVISION release 10.0 from Aveva company. Peng-Robinson equation of the state model with Twu's alpha function was selected for the modeling of the power generation cycle using LNG cold heat. Power generation efficiency was increased from 24.82% to 57.76% when using LNG as a coolant for supercritical carbon dioxide power generation cycle.

• Transactions of the Korean hydrogen and new energy society
• /
• v.30 no.2
• /
• pp.188-192
• /
• 2019

Comparative studies between single- and two-stage expansion process using LNG cold heat have been performed for a closed Rankine power generation cycle. PRO/II with PROVISION release 10.0 from Schneider Electric Company was used, and the Peng-Robinson equation of state model with Twu's alpha function was selected for the modeling and optimization of the power generation cycle using LNG cold heat. In two-stage power generation cycle, 6.7% more power was obtained compared to that of single-stage power generation cycle through the optimization works.

• Transactions of the Korean hydrogen and new energy society
• /
• v.30 no.5
• /
• pp.473-477
• /
• 2019

In this paper, cold heat price contained in the 1 ton/h of LNG has been evaluated using PRO/II with PROVISION release 10.2 from Aveva company when LNG is used to liquefy several refrigerants instead of using vapor recompression refrigeration cycle. Normal butane, R134a, NH3, R22, propane and propylene refrigerants were selected for the modeling of refrigeration cycle. It was concluded that LNG cold heat price was inversely proportional to the refrigerant supply temperature, even though LNG supply flow rate is not varied according to the refrigerant supply temperature.

• Transactions of the Korean hydrogen and new energy society
• /
• v.33 no.3
• /
• pp.261-265
• /
• 2022

In this paper, comparative studies between Linde, Claude and advanced cycle for the liquefaction of nitrogen have been completed. PRO/II with PROVISION release 2021. 1 from AVEVA company (Cambridge, UK) was used, and Peng-Robinson equation of the state model with Twu's alpha function was selected for the modeling of the condensation of nitrogen. When using Claude liquefaction, we can reduce the total compression power by 49.25% for the comparison of Linde cycle. And finally, we could conclude that 90.41% of total compression power was saved when using an advanced cycle being compared to Linde liquefaction cycle.

• Transactions of the Korean hydrogen and new energy society
• /
• v.33 no.4
• /
• pp.446-450
• /
• 2022

In this paper, comparative studies between Linde-Hampson and Claude cycle for the liquefaction of oxygen have been completed. PRO/II with PROVISION release 2021. 1 from AVEVA company (Cambridge, UK) was used, and Peng-Robinson equation of the state model with Twu's alpha function was selected for the modeling of the condensation of oxygen. When using Claude liquefaction cycle, we could reduce the total compression power by 59.51% for the comparison of Linde-Hampson cycle.