Boreum Lee

Parametric studies for CO2 reforming of methane in a membrane reactor as a new CO2 utilization process

A one-dimensional reactor model was employed to perform parametric studies for CO2 reforming of methane in a membrane reactor to investigate its feasibility as a new CO2 utilization process. The effect of key variables such as hydrogen permeance and Ar sweep gas flow rate to facilitate H2 transport from a shell side (retentate) to a tube side (permeate) on the performance in a membrane reactor was studied at various temperatures with numerical simulation validated by experimental results. In addition, increase in CH4 conversion and H2 yield enhancement observed in membrane reactor was successfully confirmed by profiles of H2 partial pressure difference between shell and tube sides. From the numerical simulation studies, the feasibility of using a membrane reactor for CO2 reforming of methane was confirmed by increased CH4 conversion and H2 yield enhancement compared to a packed-bed reactor at the same condition, which in turn leads to significant cost reductions due to a reduced operating temperature. Moreover, a window of H2 permeance and a guideline for Ar sweep gas flow rate for the efficient membrane reactor design was obtained from this study.

Process simulation and economic analysis of reactor systems for perfluorinated compounds abatement without HF effluent

AbstractNew and efficient reactor systems were proposed to treat perfluorinated compounds via catalytic decomposition. One system has a single reactor (S-1), and another has a series of reactors (S-2). Both systems are capable of producing a valuable CaF2 and eliminating toxic HF effluent and their feasibility was studied at various temperatures with a commercial process simulator, Aspen HYSYS®. They are better than the conventional system, and S-2 is better than S-1 in terms of CaF2 production, a required heat for the system, natural gas usage and CO2 emissions in a boiler, and energy consumption. Based on process simulation results, preliminary economic analysis shows that cost savings of 12.37% and 13.55% were obtained in S-2 at 589.6 and 621.4 °C compared to S-1 at 700 and 750 °C, respectively, for the same amount of CaF2 production.

Sorption enhanced catalytic CF4 hydrolysis with a three-stage catalyst-adsorbent reactor

In this study, we developed a three-stage catalyst-adsorbent reactor for the catalytic hydrolysis of CF4. Each stage is composed of a catalyst bed followed by an adsorbent bed using Ca(OH)2 to remove HF. The three stages are connected in series to enhance the hydrolysis of CF4 and eliminate a scrubber to dissolve HF in water at the same time. With a 10 wt-% Ce/Al2O3 catalyst prepared by the incipient wetness method using boehmite and a granular calcium hydroxide as an adsorbent, the CF4 conversion in our proposed reactor was 7%–23% higher than that in a conventional single-bed catalytic reactor in the temperature range of 923–1023 K. In addition, experimental and numerical simulation (Aspen HYSYS®) results showed a reasonable trend of increased CF4 conversion with the adsorbent added and these results can be used as a useful design guideline for our newly proposed multistage reactor system.

Techno-economic analysis of a biological desulfurization process for a landfill gas in Korea

ABSTRACT We report techno-economic analysis of a biological desulfurization process to remove H2S and to produce sulfur from a landfill gas (2000 m3 h−1) produced in Korea. With a process simulation model developed using Aspen Plus®, parametric assessment to determine the effect of various operating parameters such as a NaOH flow rate, a NaOH concentration, and a recycle ratio has been carried out. Based on results from process simulation, economic analysis was conducted to evaluate feasibility of this technology in Korea through a cash flow diagram, net present value (NPV), and discounted payback period (DPBP). It was demonstrated that DPBP of 6.9 years and NPV of 0.39 MM

Economic evaluation with sensitivity and profitability analysis for hydrogen production from water electrolysis in Korea

were obtained with a 10% discount rate.