• LNG and Energy System

    Tianbiao He Research Hub | Personal Website

    Hi there! I'm a Postdoc Research Fellow in the Department of Chemical and Biomolecular Engineering at the National University of Singapore with more than 7 years of experience on LNG and energy system research in both the academic and industrial fields.

     

    Currently I am focusing on LNG liquefaction process, LNG cold energy utilization, gas hydrate related technology and organic Rankine cycle.

     

  • Education 

    broken image

    Shanghai Jiao Tong University (SJTU)

    Ph.D. (2011.9-2017.4)

    Refrigeration and Cryogenic Engineering

    Supervisor: Prof. Yonglin Ju

     

    Awards

    • 2017,Xia Anshi – Heatcraft Award, (Only three Phd students won this award in China)
    • 2017, Shanghai Outstanding Graduate
    • 2016, Zhaozhumulan Third-Class Scholarship for Ph.D.
    • 2015, Zhaozhumulan First-Class Scholarship for Ph.D.
    • 2015, Student Travel Award, American Society of Cryogenics
    • 2014, National Scholarship for Ph.D.
    • 2014, Outstanding Student
    • 2013, Tang Youshuqi Scholarship
    broken image

    East China University of Science and Technology (ECUST)

    B.S. (2007.9-2011.6)

    Thermal and Power Engieering

    Supervisor: Prof. Yifei Wang

     

    Awards

    • 2011, Shanghai Outstanding Graduate
    • 2010, National Scholarship
    • 2009, National Inspiration Scholarship
    • 2009, Basf Scholarship
    • 2008, National Inspiration Scholarship
  • Experience

    broken image

    National University of Singapore

    Postdoc Research Fellow

    May 2017 - present

    Full time

    Department of Chemical and Biomolecular Engineering

     

    Collaborative Supervisor: A/Prof. Praveen Linga

    Collaborative Supervisor: Prof. Iftekhar A. Karimi

     

  • Publications

    Peer-reviewed papers and conference papers

    Note to Visitor: For a copy of our publications, contact us at cheht@nus.edu.sg

     

     

     

     

    broken image

    Tianbiao He*, Iftekhar A Karimi, Yonglin Ju*

    Chemical Engineering Research and Design, 2018, 132: 89-114.

    Liquefied natural gas (LNG) has been the fastest increasing fossil fuel in the world energy market due to its low carbon dioxide emission, high energy density, and ease of transport. However, the liquefaction of natural gas is one of the most energy-intensive industrial processes. Thus, it is very important to design new liquefaction processes and optimize the existing ones in order to reduce the energy consumption. In this paper, we present a state-of-the-art review of the recent progress on the design and optimization of NG liquefaction processes for onshore and offshore applications. The current onshore processes include the cascade, mixed refrigerant, and expander-based processes, of which the mixed refrigerant process has received the most attention. The common objective function of the onshore LNG process optimization is the minimization of the energy consumption. However, for the offshore applications, the single mixed refrigerant and nitrogen expansion processes have been considered to be the promising options. For these, deck space and sensitivity to platform waving need be considered apart from energy consumption. Finally, we propose several potential developments for NG liquefaction process design and optimization

    broken image

    Jitan Wu, Tianbiao He, Yonglin Ju*

    Journal of Chemical Engineering of Japan, 2013, 46(12): 811-820.

    The plate-fin heat exchanger (PFHE), which has been widely used in natural gas liquefaction (LNG) industry at present, has some disadvantages such as being sensitive to the impurities in the feed gas, such as water, CO2 and H2S. Compared with the PFHE, the brazed plate heat exchanger (BPHE), which has been applied in some boil-off gas (BOG) recycling LNG plants of small to middle size, has simpler inherent structure and higher impurity tolerance. In this study the BPHE is suggested to replace the PFHE to simplify or even omit the massive CO2 purification equipment for the LNG process. A set of experimental apparatus is designed and constructed to investigate the influence of the CO2 concentration of the natural gas on solid precipitation inside a typical BPHE meanly by considering the flow resistance throughout the LNG process. The results show that the maximum allowable CO2 concentration of the natural gas liquefied in the BPHE is two orders of magnitude higher than that in the PFHE under the same condition. In addition, the solid-liquid separation for the CO2 impurity is studied and the reasonable separating temperature is obtained. The solid CO2 should be separated below 135 K under the pressure of 3 MPa.

    broken image

    Tianbiao He, Yonglin Ju*

    Energy, 2016, 97: 350-358.

    The utilization of small natural gas reservoirs has attracted more and more attention. Most of the optimization studies concentrated on mixed refrigerant liquefaction process at steady-state simulation. Only a few studies have reported dynamic simulation of mixed refrigerant LNG (liquefied natural gas) process. The main purpose of this study was to design a dynamic model of mixed refrigerant LNG process for small-scale LNG plant in skid mount packages and to investigate the dynamic behaviors of this process. The variations of natural gas temperature, composition, pressure, flow rate and water-cooler temperature were selected as disturbances to test the stability and dynamic responses of the process. The dynamic responses of LNG temperature and total compressor energy consumption were the criteria to investigate the influences of disturbances on the process. Finally, the dynamic responses of disturbances were obtained and discussed. The simulation results showed that LNG temperature could go back to its set point value after a few minutes, while compressor duty varied with the disturbances. It indicated that the mixed refrigerant liquefaction process for small-scale LNG plant in skid mount packages
    could overcome some disturbances and operate at stable state.

    broken image

    Tianbiao He, Yonglin Ju*

    Energy, 2015, 88: 268-280.

    The selection of liquefaction process is of great significance for distributed-scale LNG (liquefied natural gas) plant. This paper proposes four configuration strategies of expansion liquefaction cycle for distributed-scale LNG plant, namely multistage expanders, single precooling cycle, regeneration and mixture working fluid. FOM (figure ofmerit) is applied to evaluate the liquefaction cycles for distributedscale LNG plant. Sixteen feasible liquefaction cycles are configured based on the configuration strategies and then optimized by genetic algorithm to maximum FOM for optimal synthesis. The cost analysis and exergy analysis of system are investigated. The optimized liquefaction process (Case 8) has two cycles, namely R410A precooling cycle and parallel nitrogen expansion cycle. The results show that the FOM of the optimized liquefaction cycle is 0.566 for distributed-scale LNG plant.

    broken image

    Tianbiao He, Yonglin Ju*

    Industrial & Engineering Chemistry Research, 2014, 53 (13), 5545–5553.

    In this study, a novel mixed refrigerant cycle (MRC) integrated with NGL recovery process for small-scale LNG plant is proposed and optimized. The proposed process can be used to produce LNG and NGL with low energy consumption. Genetic algorithm is chosen as the optimization method for the proposed MRC-NGL process. The unit energy consumption as an objective function is optimized with key parameters. The optimization results show that the unit energy consumption and the molar flow rate of the mixed refrigerants can be reduced by 9.64% and 11.68%, respectively, compared with that of the base case. The effects of several key parameters on the process performance are also investigated and discussed based on the optimization results. Furthermore, the exergy analyses of the main equipment are also presented and analyzed. The economic analysis also shows that the proposed process has a good profitability and a short payback period.

    broken image

    Tianbiao He, Yonglin Ju*

    Energy. 2014, 75: 349-359.

    The utilization of unconventional natural gas is still a great challenge for China due to its distribution locations and small reserves. Thus, liquefying the unconventional natural gas by using small-scale LNG plant in skid-mount packages is a good choice with great economic benefits. A novel conceptual design of parallel nitrogen expansion liquefaction process for small-scale plant in skid-mount packages has been proposed. It first designs a process configuration. Then, thermodynamic analysis of the process is conducted. Next, an optimization model with genetic algorithm method is developed to optimize the process. Finally, the flexibilities of the process are tested by two different feed gases. In conclusion, the proposed parallel nitrogen expansion liquefaction process can be used in small-scale LNG plant in skid-mount packages with high exergy efficiency and great economic benefits.

    broken image

    Tianbiao He, Yonglin Ju*

    Applied Energy, 2014, 115: 17–24.

    A novel process for small-scale pipeline natural gas liquefaction is designed and presented. The novel process can utilize the pressure exergy of the pipeline to liquefy a part of natural gas without any energy consumption. The thermodynamic analysis including mass, energy balance and exergy analysis are adopted in this paper. The liquefaction rate and exergy utilization rate are chosen as the objective functions. Several key parameters are optimized to approach the maximum liquefaction rate and exergy utilization rate. The optimization results showed that the maximum liquefaction rate is 12.61% and the maximum exergy utilization rate is 0.1961. What is more, the economic performances of the process are also discussed and compared by using the maximum liquefaction rate and exergy utilization rate as indexes. In conclusion, the novel process is suitable for pressure exergy utilization due to its simplicity, zero energy consumption and short payback period.

    broken image

    Tianbiao He, Yonglin Ju*

    Cryogenics, 2014, 61(5): 111-119.

    Liquefaction of natural gas is usually a kind of high energy consumption process. Therefore, any performance improvement of the liquefaction process will definitely reduce the energy consumption. Nitrogen expansion liquefaction process is regarded as a suitable process for small-scale LNG plant due to its simplicity, quick startup and convenient maintenance. However, the disadvantage of the process is highenergy consumption. An efficient way to lower its energy consumption is to add a precooling cycle. In this paper, two different precooling cycles including propane precooling cycle and R410a precooling cycle are proposed to the nitrogen expansion liquefaction process to improve the liquefaction process performance. Unit energy consumption as an objective function is optimized in terms of several key operating parameters. Based on the optimization results, the effects of the liquefaction rate and methane recovery rate on the process performance are investigated. The thermodynamic analyses are adopted to the processes as well as the two precooling cycles. Furthermore, the exergy analyses of the main equipment are also presented and discussed. The results show that the unit energy consumption for the nitrogen expansion process with R410a precooling and with propane precooling reduce by 22.74% and 20.02% respec-
    tively, compared with nitrogen expansion process without precooling.

    broken image

    Tianbiao He, Yonglin Ju*

    Applied Thermal Engineering, 2013, 57(1): 1-6.

    Transmission pipelines carrying natural gas across long distances usually work at high pressures (up to 10 MPa). At city gate stations the gas pressure is regulated through a set of pressure reducing processes, which are normally realized by a throttling device and waste much pressure energy. In this paper, a novel natural gas expansion liquefaction process is designed and simulated by Aspen HYSYS to utilize the pressure energy. The unit energy consumption and liquefaction rate are selected as the objective functions and are optimized with several key variables of the process. The available specific work of the gas pipelines at different pressures is also calculated and discussed. Furthermore, the exergy losses of different equipment in the process are evaluated and analyzed in details. The results show that although the liquefaction rate of this process is much lower than that of normal liquefaction processes, the novel natural gas expansion liquefaction process is suitable to utilize the gas pipeline pressure due to its low unit energy consumption, simplicity and flexibility.

    broken image

    Tianbiao He, Qiuying Li, Yonglin Ju*

    Journal of Chemical Engineering of Japan, 2013, 46(12): 811-820.

    Adsorption is an effective method for removing carbon dioxide (CO2) from natural gas. Herein, an adsorption/desorption experimental apparatus was designed and constructed to examine the performances and adsorption capacities of three typical 13X-type molecular sieves, 13X-PG, 13X-HP, and APG-II, for removing CO2 from a methane (CH4)/CO2 mixture. The effects of varying initial CO2 contents and adsorption pressures on the adsorption performance were investigated and discussed, and it was found that increasing the adsorption pressure could increase the adsorption capacity of the three molecular sieves. However, the breakthrough time for each molecular sieve was shortened at increased initial CO2 contents in the gas mixture. Moreover, the effects of varying the nitrogen-heating temperatures and flow rates on the desorption performance were investigated, and it was found that increasing the nitrogen-heating temperature and flow rate shortened the desorption times. Thus, a high nitrogen-heating temperature and a large nitrogen-flow rate are
    beneficial for improving the desorption performance of the molecular sieves.

  • ACADEMIC ACTIVITY

  • EXPERTISE

    Expertise

    • Process simulation
    • Energy system modeling
    • Optimization and control
    • Techno-economic analysis
    • Cryogenic system

    Methodology

    • Multi-objective stochastic optimization
    • Single-objective optimization
    • First princile modeling
    • Experimental study

    Computing 

    • Aspen HYSYS
    • Matlab
    • Python
    • Data analysis
    • Machine Learning

     

    Equipment

  • Projects

    A selection of research projects I have worked

    broken image

    Energy minimization at the Singapore LNG regasification terminal

    2017.5 - Present, NUS

    • First principle modelling LNG tank with multi-components and two phase
    • Compiling detail design specification and operational data.
    • Developing comprehensive model cover the operational window.
    • Achieving state objectives by applying optimization methodology.
    broken image

    LNG Cold Energy Utilization to Desalinate Seawater Employing the Hydrate Based Desalination (HBD) Process

    2017.7 - Present, NUS

    • Optimize guest gas composition, porous media properties and operating conditions to maximize the separation efficiency (salt removal, water recovery) for the HBD process.
    • Design, build and test a prototype of HBD process for sea water desalination utilizing LNG cold energy.
    • Minimize the energy requirement of the HBD process by optimizing heat exchanger networks and by process and systems integration.
    broken image

    Process Optimization and Experimental Study of Cold Box on Small-Scale Liquefied Natural Gas Plant with Skid-Mounted Packages

    2011.9 - 2017.4, SJTU

    • R&D on small-scale LNG systems in skid-mounted packages to liquefy and recover coal-bed methane for saving energy, decreasing GWP and preventing mine hazard.
    • Designed and simulated (by ASPEN-HYSYS) a single mixed refrigerant liquefaction process and a parallel nitrogen expansion liquefaction process for small-scale skid-mounted packages LNG plant with liquefaction capacity of 50000 Nm3/d.
    • Optimized two processes by adopting genetic algorithm to obtain the maximum Figure of Merit (FOM) and the minimum energy consumption.
    • Built dynamic simulation model of the single mixed refrigerant liquefaction process and investigated the dynamic behaviors of the process.
    • Designed the control structure for the single mixed refrigerant liquefaction process.
    • Building an experimental system of novel cold box with BPHEs to investigate CO2 frozen phenomenon with different CO2 concentrations in CH4/CO2 mixture gas at 3MPa.
    broken image

    Study of Floating Production Storage and Offloading (FPSO) for Offshore Oil Field Associated Gas

    2011.9 - 2012.7, SJTU

    • Designed adsorption system for LNG-FPSO to remove CO2 from natural gas. The adsorption system could reduce the size of purification system on LNG-FPSO.
    • Designed and constructed an adsorption/desorption experimental apparatus to examine the performance and adsorption capacities of three typical 13X-type molecular sieves, 13-XP, 13X-HP and APG-II.
    • The adsorption capacities with different CO2 concentrations of natural gas and different natural gas pressures were obtained and analyzed. The experimental results indicated that if CO2 concentration was lower than 2%, the molecular sieves could remove most of CO2 and the natural gas could reach the purification requirement before entering the cold box.
    broken image

    Design a Novel Cold Box with Plate Heat Exchanger for Small-scale LNG Plant (Sponsored by SWEP)

    2014.9 - 2017.4, SJTU

    • Proposed and designed a prototype of novel cold box with plate heat exchanger in order to replace the traditional cold box with plate-fin heat exchanger. The main advantage of the novel cold box is high CO2 tolerance in natural gas.
    • Studied on the CO2 frozen phenomenon with different CO2 concentrations in CH4/CO2 mixture gas at 3MPa.
    • Designed a Solid-Liquid Separator to separate solid CO2 in LNG. Different separation temperatures were obtained with different CO2 concentration.
  • Awards

    broken image

    Outstanding Reviewer of Energy Conversion and Management, 2017

    broken image

    Outstanding Reviewer of Applied Thermal Engineering, 2018

  • Download Resume

    Get a copy of my resume. Or contact me for more info.

  • Let's grab a cup!

    Available to chat about research, life and anything