Jiyong Kim

An optimization-based planning of investment strategies for a renewable energy supply system from biomass utilization

A strategic investment plan to establish renewable energy source (RES) systems plays an important role in various decision-making processes, from a stakeholder in business purposes to a policy maker for public benefits. In this study, we have developed a new optimization model to establish efficient investment strategies to design and operate a biomass to hydrogen (B2H2) system, which includes the features of RES (e.g., intermittent availability) and RES technologies (e.g., low conversion efficiency) along with various external factors on energy economy (energy price fluctuation and demand uncertainty). As a result, we identified the optimal long-term plan of investment strategy including timing, utilized amount, and capacity of facilities. In addition, we performed an economic sensitivity analysis for major parameters and evaluated a sustainability of the B2H2 system using additional metrics such as energy security and environmental protection.

The Influence of Impurities in Room Temperature Ionic Liquid Electrolyte for Lithium Ion Batteries Containing High Potential Cathode

상온 이온성 액체인 propylmethylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PMPyr-TFSI)를 리튬이차전지 전해질 용매로 사용 시 PMPyr-TFSI 내 수분 및 브롬 불순물이 전지의 성능에 미치는 영향을 연구하였다. 고전압 양극 물질인

Feasibility study and benefit analysis of biomass-derived energy production strategies with a MILP (mixed-integer linear programming) model: Application to Jeju Island, Korea

LiNi_{0.5}Mn_{1.5}O_4

Techno-economic evaluation of gas separation processes for long-term operation of CO2 injected enhanced coalbed methane (ECBM)

스피넬 구조 양극을 이용한 반쪽 전지의 전해질로 PMPyr-TFSI를 사용 하는데 있어, PMPyr-TFSI의 수분 함유량을 각각 12, 77, 1060 ppm으로 제어하고 전압 곡선 개형 및 쿨롱 효율 거동 추적을 통해 PMPyr-TFSI 수분량이 전지 성능에 부정적인 영향을 미치는 것을 구체적으로 확인하였다. 또한, PMPyr-TFSI 전해질 내의 브롬 이온 불순물 양 제어를 통하여, 전지 내에서 브롬 이온 불순물과 관련한 전기화학 부반응을 찾아 내었다. 이들 할로겐 불순물에 의한 초기 전지 쿨롱 효율저하는 눈에 띠었으나, 수명 저하에는 큰 변화가 없음을 확인하였다. 【We report the effect of the impurities including water and bromide in the propylmethylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PMPyr-TFSI) on the electrochemical performance of lithium ion batteries. The several kinds of PMPyr-TFSI electrolytes with different amount of impurities are applied as the electrolyte to the cell with the high potential electrode,

Feasibility and impact analysis of a renewable energy source (RES)-based energy system in Korea

LiNi_{0.5}Mn_{1.5}O_4

Optimization-based approach for strategic design and operation of a biomass-to-hydrogen supply chain

spinel. It is found that the impurities in the electrolytes cause the detrimental effect on the cell performance by tracing the cycleability, voltage profile and Coulombic efficiency. Especially, the polarization and Coulombic efficiency go to worse by both impurities of water and bromide, but the cycleability was not highly influenced by bromide impurity unlike the water impurity.】

Design and operation of renewable energy sources based hydrogen supply system: Technology integration and optimization

We developed a new approach to analyze the feasibility and benefits of biomass utilization strategies for energy production. To achieve this goal, we first generated a biomass-to-energy network which consists of different conversion technologies and corresponding compounds. We then developed new optimization models using a mixed integer linear programming technique to identify the optimal and alternative strategies and point out their major cost drivers. We applied these models to the biomass-derived energy supply problem on Jeju Island, Korea, to answer a wide range questions related to biomass utilization. What is the cheapest way to produce liquid fuels from available biomass on Jeju Island? How much demand can be satisfied by biomass-derived liquid fuels? What combination of technologies and biomass resources gives the best economic benefits or productivity? Based on the case study of Jeju Island, we could provide useful guidelines to policy-makers and stakeholders in the energy business.

An integrated decision support model for design and operation of a wind-based hydrogen supply system

Energy source diversification through development of coalbed methane (CBM) resources is one of the key strategies to make a country less dependent on simple energy resources (e.g., crude oil, natural gas, nuclear energy etc.). Especially, enhanced coalbed methane (ECBM) technology can be expected to secure the resources as well as environmental benefits. However, the raw CBM gas obtained from CO2 ECBM contains a considerable amount of CO2, and the CO2 content increases depending on the operation time of the facility. Considering the changes of the CBM composition, we developed process simulations of the CBM separation & purification processes based on the amine absorption to meet the design specifications (CH4 purity of product stream: 99%, CH4 recovery rate: 99%) with different CBM feed gas conditions. Using the developed simulation model, we performed an economic evaluation using unit methane production cost (MPC) considering coal-swelling types and facility operation time, and established an operation strategy under different natural gas market scenarios.