Department of Chemical and Biomolecular Engineering
Korea Advanced Institute of Science and Technology

About the Lab

Energy Fundamentals Design Laboratory

Energy storage materials ]

■ Energy storage carbon materials derived from Carbon dioxide (CO2)

 

 

 

Carbon dioxide (CO2) is one of the significant greenhouse gases that should be reduced. Therefore, many efforts have been made to capture and store CO2 to reduce its emission. However, CO2 is economical, non-toxic, and recyclable carbon source. The conversion of CO2 into useful carbon materials includes carbon nanotube (CNT), porous carbon, and graphene. However, conversion of CO2 requires severe reaction conditions of high pressure and temperature. To solve these problems, the central theme of this project is to convert CO2 into useful porous carbon materials in a benign condition using metal borohydride such as NaBH4. The resultant porous carbon derived from CO2 was used as electro-catalysts for oxygen reduction reaction in fuel cell and electrode materials for supercapacitors in this project.



■ Fuel cell catalyst using B-/N- doped activated carbon (AC)

 

 

 

Fuel cell has been paid great attention as an efficient energy conversion device which can directly convert chemical energy into electrical energy. Pt-based materials are widely used as fuel cell catalyst. However, commercialization of fuel cell is disturbed by scarcity, high cost, and low durability of Pt-based materials. Therefore, efforts to find alternatives for fuel cell catalyst have been performed. Among many alternatives, heteroatom (B, N, etc.)-doped carbon materials are mainly focused as research field. In our laboratory, a commercial activated carbon (AC) is used as a carbon source to produce fuel cell catalysts. AC is cheap and easily obtainable material, and B-/N-doped AC shows a remarkable oxygen reduction reaction (ORR) activity and catalytic durability. The objective of this research is production of B-/N-doped AC material which has comparable ORR activity to commercial Pt catalyst.



■ Secondary batteries and Supercapacitors

 

 

 

 To date, the electric generation demand have increased on the world. Today, most of electrical energy is obtained from fossil fuels. However, these sources generated large amount of CO2 emission, a greenhouse gas. The environmental concerns have invoked the interest in generating electricity from renewable energy. But, these energy sources, solar and wind energy are not reliable and constant. Therefore, the electrical energy storage will play a significant role in enhancing the reliability of the renewable power system. Supercapacitors have been studied by many research groups as a potential electricity storage device with an electrical double layer of a high surface area electrode. Recent efforts have been made to convert CO2 to B-doped porous carbon that is utilized for supercapacitor after KOH treatments and to upgrade a non-conducting polymer to nitrogen-doped porous carbon for supercap.



■ Secondary batteries and Supercapacitors

 

 

 

Recent publications

[1] Effect of boron-nitrogen bonding on oxygen reduction reaction activity of BN Co-doped activated porous carbons, Seoyeon Baik and Jae W. Lee, RSC Adv., 2015, 5, 24661

[2] Effects of Boron Oxidation State on Electrocatalytic Activity of Carbons Synthesized from CO2, A. Byeon, Seoyeon Baik, and Jae W. Lee, Journal of Materials Chemistry A, 2015, 3, 5843

[3] Concurrent Production of Carbon Monoxide and Manganese (II) Oxide through the Reaction of Carbon Dioxide with Manganese, Wonhee Lee and Jae W. Lee, ACS Sus. Chem. Eng., 2014, 2(6), 1503

[4] Boron-doped carbon/iron nanocomposites as efficient oxygen reduction electrocatalysts derived from carbon dioxide, J. Zhang and Jae W. Lee, Chem. Commun., 2014. 50(48), 6349

[5] Synthesis of Highly Electrocapacitive Nitrogen-doped Graphitic Porous Carbons using Polyacrylonitrile, Kyung Taek Cho, Sangbok Lee, and Jae W. Lee, J. Phys. Chem. C, 2014, 118, 9357





Energy storage materials ]


■ Intensification of reaction and separation

 

The intensification of reaction and separation proposes dramatic economic savings, a higher production yield, and a circumvention of pinch points. Dramatic economic savings come from the simplification of a complex process and the utilization of a reaction heat for a distillation. The shift in chemical equilibrium resulting from the simultaneous separation and removal of the products cause a higher production yield. Also this shift of chemical equilibrium leads to the circumvention of pinch points. The main task in realizing this technology is to visualize the interaction between reactions and separations on the basis of reaction and phase equilibriums.



■ Feasibility of a continuous reactive distillation

 

The intensification of reaction and separation proposes dramatic economic savings, a higher production yield, and a circumvention of pinch points. Dramatic economic savings come from the simplification of a complex process and the utilization of a reaction heat for a distillation. The shift in chemical equilibrium resulting from the simultaneous separation and removal of the products cause a higher production yield. Also this shift of chemical equilibrium leads to the circumvention of pinch points. The main task in realizing this technology is to visualize the interaction between reactions and separations on the basis of reaction and phase equilibriums.

 

 

Figure 1. A basic schematic of a reactive distillation and tetrahedral composition space of reaction and phase equilibriums



■ Feasibility of a batch reactive and batch reactive extractive distillation

 

 

Figure 3. Circumvention of pinch points in batch extractive distillation


Recent publications

[1] Feasibility Evaluation of Quinary Heterogeneous Reactive Extractive Distillation, Dohyung Kang, Kang Wook Lee, and Jae W. Lee, Ind. Eng. Chem. Res., 2014, 53(31), 12387

[2] Estimation of Still Trajectory for the Feasibility Evaluation of Batch Reactive Distillation Systems, J. Chin and Jae W. Lee, Ind. Eng. Chem. Res., 2008, 47(11), 3930





Clathrate hydrates ]

 

Clathrate hydrates having both physical and chemical characteristic features of ice-like materials are crystalline compounds in which guest molecules such as methane, ethane, carbon dioxide, cyclopentane (CP), etc. are entrapped in host water cages formed by the hydrogen-bonded networks of water molecules. Clathrate hydrates are evaluated as not only one of main factors for pipeline blockage in oil and gas processes (flow assurance) but also a future energy storage media for natural gas. Our laboratory mainly focus on the flow assurance problem, especially the understanding and identification of dynamic adhesion behavior and crystal growth patterns in clathrate hydrate systems.




Figure 1. Conceptual image of hydrate plug formed in a subsea hydrocarbon pipeline



■ Dynamic Adhesion Behavior between Clathrate Hydrates and Solution Droplets

 

During the extraction process of oil and gas, the existence of water (host), gas (guest) can lead to the formation of hydrate inside the pipeline, and thus; hydrate particles can be aggregated and agglomerated down the pipeline. Through continuous growth of hydrate particles, hydrate plugging happens, which can lead to a halt of production due to the pipeline blockage. Therefore, the interfacial dynamic adhesion behavior has to be identified essentially to understand the interaction between hydrate particles and water droplets in the pipeline. 


The main goal of this proposal is to understand the dynamic adhesion interactions between clathrate hydrates and various oil-water interfaces. Elucidating the adhesion behaviors of hydrate particles in multi-phase systems consisting of gas, oil, water, and solid surfaces may provide fundamental insights into the avoidance of hydrate plugs in gas/oil delivery lines and processing units. To understand the adhesion behavior subject to the phase transition and fluid motion, the mechanism for capillary bridge formation and aggregation between hydrate particles, partially converted water droplets, and water droplets should be identified in a micro-scale domain. Then, this micro-scale adhesion mechanism can be interpreted to understand the macro-scale adhesion behaviors. We will quantify the changes in dynamic adhesion when accompanying surface-active agent (surfactants and nano-particles) injection, substrate (e.g. metal surfaces in the pipelines) aging and various surface properties of roughness, hydrophobicity, and hydrophilicity.



Figure 2. Variations of contact force between clathrate hydrates and solution droplet from contact to detachment



■ Understanding the Crystal Growth Pattern at the Water – Oil Interface

 

A batch distillation The continuous hydrate crystal growth at the interface of water – oil is evaluated as one of main factors for the hydrate plugging. In addition, the morphology, especially the size, shape and the structure of hydrates, should be considered for better understanding. Therefore, the identification of the feature of hydrate crystal growth at the water – oil interface is critical to understand the hydrate plugging mechanism in the pipeline.


The main goal of this proposal is to understand the mechanism of nucleation, crystal growth of clathrate hydrate at the water – oil interface. We will introduce the water/oil soluble surfactant and/or nano-particles into the water – oil interface and observe the growth patterns of hydrate crystal. The effects of surface-active agent injection into the water – oil interface can be monitored by the optical microscope and Micro differential scanning calorimetry.



Figure 1. Conceptual hydrate crystal growth in the presence of oil soluble surfactant at the water – oil interface


Recent publications

[1] Tuning Behaviors of Methane Inclusion in Isoxazole Clathrate Hydrates, Minjun Cha, Seungjun Baek, Wonhee Lee, Kyuchul Shin and Jae W. Lee, J. Chem. Eng. Data., 2015, 60(2), 278

[2] Inclusion of Thiophene as a Co-Guest in Structure II Hydrate with Methane Gas, Minjun Cha, Seungjun Baek, Huen Lee, and Jae W. Lee, RSC Adv., 2014, 4(50), 26176

[3] Hydrophobic particle effects on hydrate crystal growth at the water - oil interface, Minjun Cha, Seungjun Baek, J. Morris, and Jae W. Lee, Chemistry Asian Journal., 2014, 9(1), 261

[4] Adsorption Isotherm of Gemini-surfactants onto Hydrates, O. Salako, C. Lo, A. Couzis, P. Somasundaran, and Jae W. Lee, J Colloid Interface, 2013, 412, 1

[5] Thermodynamic and Spectroscopic Identification of Methane Enclathration in the Binary Heterocyclic Aromatic Ring Compound Hydrates, Minjun Cha, H. Lee, and Jae W. Lee, J. Phys. Chem. C, 2013, 117(45), 23515




[Biomass convers]

 

 


Recently, biofuels have attracted public attention as a source of renewable energy for replacing fossil fuel. Microalgae can take carbon dioxide from the air and grow faster than terrestrial plants. Using microalgae, high-concentration culture is possible in large quantities and even in extreme environments. Producing biodiesel from microalgal lipids is feasible since microalgae can accumulate lipid levels that are greater than 50% of their dry cell weight. Usually microalgae are photoautotrophic microbes, but in addition to using free sunlight as an energy source, microalgae can be cultivated using the nitrogen, phosphorus and hydrocarbons in wastewater.


After extraction of the lipids from cultivated microalgae, the extracted oils are usually converted to fatty acid methyl ether (FAME) using methanol and acid catalyst in a transesterification reaction. Such FAME can be used as a biodiesel after purification. Because microalgae are grown in liquid media, extraction is usually classified as wet extraction or dry extraction depending on whether or not the culture broth was dried before the lipid extraction step. Most of the current extraction processes are carried out after drying the wet microalgae to increase the amount of lipid extracted from the biomass. However, this drying process is responsible for up to 59 % of the total energy consumed during the biodiesel production. 


To substantially reduce the impact of the energy consumed for the current drying process, improvement of the efficiency of wet extraction by adding other operations has recently emerged as a very important issue. Our current research focus is to combine the three processes of drying, extraction, and transesterification into one pot process (wet in-situ transesterification) to dramatically realize an efficient design of biodiesel production.


Recent publications

[1] In situ transesterification of highly wet microalgae using hydrochloric acid, B. Kim, H. Im, and Jae W. Lee, Bioresource Tech., 2015, inpress

[2] Concurrent lipid extraction and transesterification of wet microalgae, H. Im, H. Lee, M. Park, J. Yang, and Jae W. Lee , Bioresource Tech., 2014, 152, 534





Jae Woo Lee (이재우)
Professor


Office Phone: +82-42-350-3940
Fax: +82-42-350-3910
E-mail: jaewlee@kaist.ac.kr
Homepage: http://efdl.kaist.ac.kr

0

추천하기

0

반대하기

ProfessorJae Woo Lee

Hits2,251

  • 페이스북 공유
  • 트위터 공유
  • Google+ 공유
  • 인쇄하기