Showing papers by "Preeti Aghalayam published in 2018"
TL;DR: In this article, the effects of different operating conditions, coal properties and design parameters on key performance indicators (e.g., exit gas quality, energy generation rates etc) were examined. And the authors demonstrated the importance of a process model to determine the best conditions for UCG process and to evaluate feasibility of the process for a coal seam under consideration.
14 citations
TL;DR: In this paper, a new power plant layout which uses part of the sequestered flue gas stream for high-pressure gasification of the coal within the framework of an IGCC power plant with CO2 capture was proposed.
Abstract: CO2 capture from coal-fired power plants is necessary for continued use of coal as a fuel. Proven CO2 capture techniques such as amine absorption and oxyfuel combustion entail significant energy penalty leading to considerable decrease in the net thermal efficiency of the power plant. Recent studies of high-ash Indian coals show that CO2 has sufficient reactivity for coal gasification in temperature ranges of interest to IGCC. Against this background, we analyse in the present study, a new power plant layout which uses part of the sequestered flue gas stream for high-pressure gasification of the coal within the framework of an IGCC power plant with CO2 capture. Detailed thermodynamic calculations of the new plant layout, referred to here as Oxy-RFG-IGCC-CC, using commercial power plant simulation software show that the optimized Oxy-RFG-IGCC-CC plant with CO2 capture produces power at an overall thermal efficiency of 34.2%, which is nearly the same as that of current generation of pulverized coal boiler-based power plants without CO2 capture or that of a conventional IGCC with post-combustion capture. The proposed simpler layout is also 1.9% more efficient than a comparable CO2-capture-enabled IGCC plant that uses steam for coal gasification.
4 citations
TL;DR: In this article, the authors developed a generic kinetic model applicable to various lean NOx traps (LNT) catalyst formulations and applied it to the design and analysis of the LNT reactor.
Abstract: Lean NOx traps (LNT) is an after-treatment technique that is used for NOx abatement in lean-burn engines. The objective of this work is to develop a generic kinetic model applicable to various LNT catalyst formulations and to apply it to the design and analysis of the LNT reactor. The kinetic model of 16 reactions is proposed using Langmuir–Hinshelwood kinetics. It is validated against experiments reported in the literature, performed for a family of catalyst formulations that use Pt-group metals as the active catalyst and barium-based NOx storage, and is capable of predicting the performance with minimal modification of parameters. A kinetic analysis highlights the contribution of each reaction to the overall kinetic scheme in order to determine the important steps and qualitatively validate the model. A reactor-level analysis is done by varying the operating conditions and the time scales of the lean and rich phases are optimized.
3 citations
01 Jan 2018
TL;DR: In this paper, the authors discuss various experiments and models of underground coal gasification cavities, with a focus on the effects of reaction chemistry and thermomechanical spalling on cavity evolution.
Abstract: Underground coal gasification is an in situ coal utilization technique that has immense potential as a future clean coal technology. UCG possesses a number of advantages including the ability to use deep and unmineable coals. The most important component of UCG is the underground “cavity”—which serves as a chemical reactor with rich interplay of kinetics and transport. Field and laboratory-scale experiments have revealed several interesting features of the UCG cavity. Modeling studies on the UCG cavity involve fundamental models and CFD simulations. In this chapter, we will discuss various experiments and models of UCG cavities, with a focus on the effects of reaction chemistry and thermomechanical spalling on cavity evolution.