Abstract

Gasification is one of the prominent and technically efficient technologies for converting solids like coal, biomass or solid waste into useful gas known as “syngas.” Several configurations are in use today among which entrained flow gasifiers have several advantages over other configurations. Presently research is more focused on micro-level modifications in the configurations which have a significant impact on overall performance of gasification. Scant, literature is available for comparison of slurry over dry form of feedstocks, especially with low-grade coals. Hence, present research aims to establish a concrete finding regarding the impacts of slurry versus the dry condition of coal on the overall performance of gasification. To achieve this goal, a two-dimensional computational fluid dynamic (CFD) model of downdraft gasifier was developed in commercial CFD software FLUENT for performing numerical simulations with indigenous coal feedstock. Rich oxidant conditions (95% oxygen and 5% nitrogen) were maintained in the gasifier for the gasification. The performance of gasification was measured by comparing efficiencies of gasification and the quality of syngas produced with different coal forms. As per simulation results, coal forms and operating conditions caused a significant effect on overall gasification performance. In syngas composition, H₂ mol fraction reached at maximum, when the slurry form of coal was used for gasification. This effect is remarkable for generating hydrogen-rich fuel from lignite without consuming steam externally.

Graphic abstract

中文翻译：

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煤浆和干燥形式的低阶煤（褐煤）对合成气质量的影响

摘要

气化是将煤，生物质或固体废物等固体转化为有用气体（称为“合成气”）的重要技术高效技术之一。当今使用几种配置，其中夹带流化气化炉具有优于其他配置的多个优点。目前，研究更多地集中在对气化整体性能有重大影响的构型的微观水平修改上。很少有文献可以比较干形式的原料中的浆料，尤其是低级煤。因此，本研究旨在建立一个关于煤浆与煤干条件对气化整体性能的影响的具体发现。为了实现这个目标，在商用CFD软件FLUENT中开发了一个向下流式气化炉的二维计算流体动力学（CFD）模型，用于对本地煤炭原料进行数值模拟。在气化炉中保持浓的氧化剂条件（95％的氧气和5％的氮气）进行气化。气化性能是通过比较气化效率和不同煤型产生的合成气质量来衡量的。根据模拟结果，煤的形式和运行条件对整体气化性能产生了重大影响。在合成气中，H 气化性能是通过比较气化效率和不同煤型产生的合成气质量来测量的。根据模拟结果，煤的形式和运行条件对整体气化性能产生了重大影响。在合成气中，H 气化性能是通过比较气化效率和不同煤型产生的合成气质量来衡量的。根据模拟结果，煤的形式和运行条件对整体气化性能产生了重大影响。在合成气中，H 当使用煤的浆态形式进行气化时，最大分数为₂摩尔。对于从褐煤中生成富氢燃料而无需从外部消耗蒸汽的情况，此效果非常显着。

图形摘要