Constructal thermodynamic optimization for dual-pressure organic Rankine cycle in waste heat utilization system

In this study, a novel system comprising of a two-stage organic Rankine cycle, driven by geothermal energy and coupled with a proton exchange membrane electrolyser, is investigated and optimized from thermodynamic and exergoeconomic viewpoints. Various working fluids are considered so as to ascertain the effects of thermophysical properties on the performance of the system. The electricity output from the two-stage organic Rankine cycle is employed to produce hydrogen through electrochemical reactions in the proton exchange membrane electrolyser. The effects are assessed on key parameters of variations in geothermal water temperature and the pressure ratio of high-pressure organic Rankine cycle turbine. Considering three distinct cases, a thorough optimization is performed utilizing a genetic algorithm. It is concluded that a 2-3 percent-point improvement in energy efficiency, as well as a 35% to 41% increase in hydrogen production and a 9.5% to 12% reduction in cost per unit exergy of hydrogen can be achieved via optimization. R123 is shown in the optimization to perform the best among the considered working fluids, with isopentane performing second best.

Evaluation and optimization of a novel geothermal-driven hydrogen production system using an electrolyser fed by a two-stage organic Rankine cycle with different working fluids

With massive coal consumption in the industry, the increasing requirements for improving combustion efficiency and environmental protection raise widespread interests. Laser-induced breakdown spectroscopy (LIBS) shows the merits of high-speed, minimally destructive, simple preparation, etc. Combining it with the analytical chemistry methods have become a promising way for coal analysis. In this work, LIBS instruments for collecting coal spectra, pretreatment methods for coal samples, preprocessing of coal data, and analytical chemistry methods for coal analysis were summarized. Moreover, LIBS applications, including coal ranks, combustion efficiency, and environmental protection, are provided. Finally, this review proposes a description of limitations and the potential developing trend for this topic.

A review of laser-induced breakdown spectroscopy for plastic analysis

Analysis and optimization of a fuel cell integrated with series two-stage organic Rankine cycle with zeotropic mixtures

Vanadium redox flow battery (VRFB) has attracted much attention because it can effectively solve the intermittent problem of renewable energy power generation. However, the low energy density of VRFBs leads to high cost, which will severely restrict the development in the field of energy storage. VRFB flow field design and flow rate optimization is an effective way to improve battery performance without huge improvement costs. This review summarizes the crucial issues of VRFB development, describing the working principle, electrochemical reaction process and system model of VRFB. The process of flow field design and flow rate optimization is analyzed, and the battery attributes and metrics for evaluating VRFB performance are summarized. The focus of the research is the methods of flow field design and flow rate optimization, and the comprehensive comparison of battery performance between different flow field designs. Literature analysis shows that reasonable flow field design can improve the uniformity of electrolyte, improve battery attributes and metrics, and thus improve the overall performance of VRFB and reduce the cost. 

Vanadium redox flow batteries: Flow field design and flow rate optimization

Laser-Induced Breakdown Spectroscopy (LIBS) technique is used to determine the emission intensity of inorganic elements, such as Si, Fe, Mg, Al, Ca, Na, and K in coal samples. The average emission intensity of the inorganic elements increases with the ash content of the coal sample with R2 = 0.82. Using the LIBS data, partial least square regression (PLSR)-based multivariate analysis was performed to determine the coal ash content. The PLS approach combined with the LIBS technique resulted in the coefficient of correlation R2 = 0.93, root-mean-square error RMSE = 3.5%, standard deviation SD = 11.7% and resolution = 3.7% corresponding to the reference ash data.

Determination of Ash Content in Coal Using Laser-Induced Breakdown Spectroscopy with Multivariate Analysis

Effect of electrolyte parameters on the discharge characteristics of planar zinc‐air flow battery with polymer gel electrolyte as separator

A novel method of spectrum analysis based on frequency of absorption spectrum is developed. Gas sensing of Sulphur dioxide in 200-220 nm has error due to spectral interference from absorption of other gases. This is minimized by analysing frequency component of spectra obtained by continuous wavelet transform which represents only Sulphur dioxide.

Application of continuous wavelet transform for elimination of spectral interference in UV spectroscopy

The origin, formation mechanism, and emission persistence time of atomic (C I) and molecular (CN Violet system and C2 Swan system) carbon emissions from coal plasma generated by laser ablation were studied using Time-resolved LIBS.

Understanding the mechanism of molecular carbon emissions using time-resolved LIBS during online coal characterization

Process industry mostly uses steam as an indispensable source of energy. We are presenting a technique to measure quality in real time where single laser diode tuning capabilities is being utilized to generate arbitrary modulated laser intensity for non-absorbing and absorbing wavelength of water vapor and eliminates uses of multiple laser source.

Satyanarayanan Seshadri

Papers

Determination of Ash Content in Coal Using Laser-Induced Breakdown Spectroscopy with Multivariate Analysis

Effect of electrolyte parameters on the discharge characteristics of planar zinc‐air flow battery with polymer gel electrolyte as separator

Application of continuous wavelet transform for elimination of spectral interference in UV spectroscopy

Understanding the mechanism of molecular carbon emissions using time-resolved LIBS during online coal characterization

Real-time Steam Quality Measurement using Tunable Diode Laser Absorption Spectroscopy for Process Industries