【作者】 徐进；

【导师】 魏新利； 刘宏；

【作者基本信息】 郑州大学 ， 化工过程机械， 2009， 硕士

【摘要】 本文主要针对生物质热解实验设备中冷凝系统经常发生堵塞的问题进行研究,在此基础上,设计新的冷凝用换热器进行实验并用Fluent软件进行优化。主要的研究成果如下:1.利用气相色谱和气质联用仪分析了生物油和堵塞物的物质组成和含量比例,分析引起堵塞物形成的主要成分。2.造成冷凝器管路堵塞的机理是由于生物质热解气携带了大量细微的炭颗粒进入冷凝用换热器,在换热器表面形成气溶胶、液固溶胶,通称为换热器的微粒污垢。污垢物质不断堆积,最终导致冷凝用换热器管路堵塞。3.热解反应温度和气固分离的程度对污垢的形成有至关重要的作用。实验发现当热解温度控制在500-520℃时对热解形成的炭产量有很好的抑制。4.设计加装了两级旋风分离器,对热解气和炭颗粒分离效果明显改善。设计了新冷凝换热器。换热器内筒结构选用浮头式;换热管采用U型管;换热器外筒增设水夹套。利用Fluent模拟换热器内流体流动,优化换热器结构。安装调试完成后进行热解实验,达到预期的缓解堵塞的效果。更多还原

【Abstract】 This paper mainly research the problem of block happened in the condensation system of biomass pyrolysis equipments. The heat exchanger, based on the results above, had been designed for new structure and optimize by the CFD code fluent. The following introductions are the main research results.1. Via GC and GC/MS, to analysis the composition and quality rate of bio-oil and substances of block. The main aim is to find out the vital substance what causes the block.2. The principle of block in condensers is that pyrolysis gas carry with a great amount of char to flow into the condensers and the mixture form the gas dispersoid and liquid-soild dispersoid usually called small particles fouling of condensers. With the increasing volume of fouling, it finally causes the block of tubes.3. The main influencing factors of fouling are the temperature of pyrolysis and the degree of separation of gas and char by cyclones. When the pyrolysis temperature had been controlled in the range of 500 and 520℃, the forming of fouling had been suppressed better.4. Installing the second level of cyclone, it can make the better separation of gas and char than before. The new structure of the heat exchanger had been designed. The structure of new heat exchanger consists of floating head condenser, U-tube as the inner tube of heat exchanger and the jacket outside cyclinder. The structure of heat exchanger might be optimized via stimulation of fluid flow by CFD code Fluent. After the installing and adjustment for new heat exchanger, the anticipated aim of releasing block had been accomplished.更多还原