在双碳目标背景下,燃煤机组耦合生物质直燃发电是充分利用近零碳排放的生物质能源资源的可行和现实途径之一。目前,国内燃煤机组耦合生物质直燃发电的示范工程较少、技术成熟度还有待提升,存在燃料破碎和输运、燃烧组织、锅炉受热面腐蚀等问题。计算流体力学为能源与动力装置优化设计与运行提供了一种有效的研究方法。重点综述了生物质颗粒气固两相动力学模型的研究现状,总结了其存在的问题,并提出了研究建议。生物质颗粒较大,且呈不规则的非球形;在国内目前缺乏成熟技术方案和相关经验的情况下,准确模拟不规则、非球形生物质大颗粒的运动轨迹是准确模拟其燃烧过程的基础和关键,也是该领域的难点。但在稀相流条件下,目前还缺乏非球形生物质大颗粒气固两相动力学通用模型。建议加强生物质颗粒高效燃烧气固两相动力学模型的基础理论研究,通过颗粒分辨的直接数值模拟获得各种典型的非球形颗粒的曳力升力系数和力矩系数的新关联式,耦合非球形颗粒平移及旋转运动,构建适用于非球形生物质大颗粒的通用气固两相动力学模型,进一步开展试验验证后应用于工业界的多相流模拟中,为揭示生物质与煤粉直燃耦合过程中的颗粒输运和热转化特性提供支撑。

Co-firing biomass power generation in power plants is one of the feasible and realistic ways to make full use of biomass energyresources with near-zero carbon emissions in the context of dual carbon targets. Nowadyas, there are few demonstration projects of co-firing biomass power generation in power plants. The technical maturity needs to be improved. There are problems such as fuel crushing andtransportation, combustion organization, and boiler heating surface corrosion. Computational Fluid Dynamics (CFD) provides an effectiveresearch method for the optimal design and operation of energy and power plants. The research status of the gas-solid two-phase dynamic model of biomass particles was mainly reviewed. The existing problems were summarized, and the research suggestions were proposed.Biomass particles are large and exhibit irregular non-spherical. In the absence of mature technology and relevant experience in China, theaccurate simulation of the motion trajectory of irregular and large for non-spherical biomass particles is the basis and key to accurately simulate the combustion process, which is also a difficulty in this field. However, there is no general model of gas-solid two-phase dynamicsfor large non-spherical biomass particles under dilute phase flow conditions. It is suggested to strengthen the basic theoretical research onthe gas-solid two-phase dynamic model for efficient combustion of biomass particles. A new correlation of drag-lift coefficient and moment coefficient of various typical non-spherical particles is obtained by particle-resolved direct numerical simulation(DNS), which couples the translational and rotational motion of non-spherical particles. A general gas-solid two-phase dynamic model for large non-spherical biomass particles is constructed. After further experimental verification, it is applied to multiphase flow simulation in industry, whichprovides support for revealing the particle transport and thermal conversion characteristics in the coupling process of co-firing biomasspower generation in power plants.

0 引言

1 直燃耦合技术及应用

   1.1 耦合燃烧技术

   1.2 国内外直燃耦合生物质技术应用

2 直燃耦合数值模拟

3 非球形颗粒气固两相流模型研究现状

4 直燃耦合生物质气固两相动力学模型存在的问题

5 结语及展望