循环流化床料腿排灰装置调节特性实验研究

发布时间：2018-09-04 08:19

【摘要】：煤气化技术是高效、清洁利用煤炭资源的重要途径,符合我国当前“多煤、少油、缺气”的国情,其中循环流化床煤气化技术因其煤种适应性好、碳转化率高、易于脱硫等特点具有广阔的发展前景。对于循环流化床,循环倍率对碳转化率、炉内温度水平甚至脱硫效率等都有重要影响,而料腿排灰技术可以通过改变料腿的排灰量对循环倍率及飞灰夹带量进行调节。排灰量的调节与控制是料腿排灰技术的关键,高温条件下通常采用非机械阀进行控制。本文对U型返料阀进行了研究,并将U型返料阀用于料腿排灰,探讨了排灰阀的流动特性。设计并搭建了循环流化床及料腿排灰冷态实验台,以石英砂为床料、空气为流化介质,对循环流化床U型返料阀给料室松动风和返料室流化风的流动特性进行了研究。实验结果表明,松动风量与主床固体循环通量有较好的线性关系,可调性较高；返料室内充分流化后固体通量随流化风量的增加基本不再改变,可调性较差。通过采用不同粒径的石英砂,研究了颗粒粒径与主床固体循环通量的关系。结果表明,颗粒粒径越小U型返料阀的返料能力越强,达到同样固体通量所需的风量越小。实验发现,料腿内料位高度对U型返料阀内颗粒流动有所影响,料位越高立管内压降越大,U型返料阀的返料能力越强。对U型返料阀的阻力特性同样做了探讨,循环流化床内固体循环通量越高,U型返料阀阻力越小,有较好的自平衡能力。基于U型返料阀的原理,通过增加一个给料室,设计了料腿排灰调节阀,并开展了给料室和排灰室风量对排灰阀排灰特性的影响的研究。实验结果表明,水平孔口的大小对排灰量有所影响,将水平孔口面积不同的给料室相组合可得到不同的调节特性。对两个给料室的研究表明,两个给料室会相互影响,其同时开启时调节范围比单独开启之和要大。讨论了两个给料室的配合方式,使其能够在排灰阀总充气量尽量小的情况下获得足够大的调节范围。对于排灰阀,一个给料室主调,另一个给料室辅助,可以获得更灵活的调节能力以及更广的调节范围。对排灰阀的不足也进行了研究,提出了进一步的改进方法。
[Abstract]:Coal gasification technology is an important way to make use of coal resources efficiently and cleanly. It accords with the current situation of "more coal, less oil and less gas" in our country. Circulating fluidized bed coal gasification technology has high carbon conversion rate because of its good adaptability of coal type. The characteristics such as easy desulphurization have a broad development prospect. For circulating fluidized bed (CFB), circulating rate has an important effect on carbon conversion, temperature level and desulfurization efficiency, etc. The rate of cycle ratio and fly ash entrainment can be adjusted by changing the amount of ash discharged from feed leg. The regulation and control of ash discharge amount is the key of material leg ash removal technology, and the non-mechanical valve is usually used to control it under high temperature. In this paper, U type return valve is studied, and the flow characteristic of U type return valve is discussed. The cold test bench of circulating fluidized bed and leg ash was designed and built. The flow characteristics of loose air and fluidized air in feed chamber of U-type return valve in circulating fluidized bed were studied with quartz sand as bed material and air as fluidized medium. The experimental results show that the loose air flow has a good linear relationship with the flux of solid circulation in the main bed, and the solid flux is not changed with the increase of the fluidized air flow rate, and the adjustability is poor. The relationship between particle size and solid circulation flux of main bed was studied by using quartz sand with different particle sizes. The results show that the smaller the particle size, the stronger the recharge capacity of U-type return valve, and the smaller the air volume required to achieve the same solid flux. It is found that the height of the material level in the material leg has an effect on the flow of particles in the U-type return valve, and the higher the material level is, the greater the pressure drop in the vertical pipe is, and the stronger the return ability of the U-type return valve is. The resistance characteristics of U-type return valve are also discussed. The higher the solid circulation flux in circulating fluidized bed is, the smaller the resistance of U-type return valve is, and the better self-balancing ability is. Based on the principle of U-type return valve, a feed leg ash regulating valve is designed by adding a feeding room, and the influence of air volume in feed room and ash discharge chamber on the ash discharge characteristics of ash discharge valve is studied. The experimental results show that the size of the horizontal orifice has an effect on the ash discharge, and different adjusting characteristics can be obtained by combining the feed chamber with different horizontal orifice area. The study on the two feed chambers shows that the two feed chambers interact with each other, and the adjustment range of the two feeders is larger than that of the single opening at the same time. The matching mode of the two feeding chambers is discussed, which can obtain a wide enough adjustment range under the condition that the total air volume of the ash discharge valve is as small as possible. For ash valve, one feed chamber main tone, the other feed room auxiliary, can obtain more flexible adjustment ability and a wider range of regulation. The deficiency of ash-discharging valve is also studied, and further improvement method is put forward.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ545;TQ051.13

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