Influence of vent air valve opening on combustion characteristics of a down-fired pulverized-coal 300 MWe utility boiler

Industrial experiments have been performed on a down-fired pulverized-coal 300 MWe utility boiler with vent air valve opening of 100% and 40%. The gas temperature distribution along the primary air and coal mixture flow, gas temperature distribution in the furnace, and gas components such as O₂, CO, CO₂ and NO_x in the near-wall region were measured for the first time. The influence of vent air valve opening on coal combustion in the furnace was determined. The results indicate that ignition of the primary air and pulverized-coal mixture is delayed. The position of the gas temperature peak is above the arches. Emission of NO_x is up to 2101 mg/m³ (at 6% O₂ dry) with vent valve opening of 40%.     

双入口直切式旋风分离器流场内旋进涡核现象的研究

主要研究了双入口直切式旋风分离器流场中的一种涡核非稳态现象———旋进涡核。实验表明 ,旋进涡核存在于分离器排尘口下部及锥体中下部 ,在排尘口处涡核摆动最强烈 ,同时涡核的摆动在一定操作参数下具有一定的频率和幅值 ,因此势必会造成粉尘的夹带返混 ,致使分离器效率降低。与单入口旋风分离器相比 ,双入口直切式旋风分离器内旋进涡核频率降低 ,幅值减小 ,但范围不变。说明入口形式是否轴对称对旋进涡核的存在与否不起主要作用     

哈尔滨气化厂粗煤气除尘系统的改造

原粗煤气除尘系统分离效果不好,给后续的CO变换系统的正常运行带来了许多困难。为解决此问题,在原除尘系统增设2级E-Ⅱ型旋风分离器和高效过滤器进行分离。经生产实际考核,E-Ⅱ型旋风分离器适合用于以煤为原料生产的粗煤气除尘系统。     

旋风汽水分离器内液滴轨迹模拟研究

旋风分离器内部汽水两相流场是非常复杂的三维强旋转湍流流动,液滴运动非常复杂,且带有很大的随机性,因此很难通过解析的方法预报内部流动状况。使用fluent软件,运用计算流体力学的方法对旋风分离器内部的液滴流动进行了数值仿真研究。结果表明,小粒径液滴与较大的粒径的液滴相比,由相同位置进入,其运动轨迹有所不同。小粒径液滴受气流脉动影响和受大粒径液滴的携带作用较为显著,对分离性能的影响较大。所以,液滴粒径越大,分离效率越高。     

基于FPGA的CORDIC算法的改进及实现

介绍了CORDIC算法的基本原理,分析了其具体计算方法。针对利用CORDIC流水线实现FFT蝶形运算耗费资源多的问题,依据CORDIC计算迭代系数的方法改进了CORDIC流水线的结构形式,使其适应FFT算法。选用ALTERA公司CycloneII系列的EP2C35F672C6来实现整个FFT处理器,并对设计进行了时序仿真和硬件仿真。通过比较,计算结果与设计基本一致。     

Optimization and industrial application of recycled hydrogen desulfurization process in a hydrogenation unit

A novel gas-liquid cyclone operated under high-pressure conditions (13.7 MPa) was developed. For optimizing recycled hydrogen desulfurization system, an array of this type of cyclone separators was set in the top of the high-pressure separator and desulfurizing tower. The industrial application results illustrated that the average separation efficiency of the cyclone deliquid device was 85.4%. By adopting the optimized system, a large amount of investment cost was saved and a series of significant improvements were achieved.     

旋风筒阻降浅论

介绍了旋风筒阻降(压降)的定义及其测量方法、旋风筒阻降的计算公式,分析了操作参数和结构尺寸对旋风筒阻降的影响、旋风筒阻降的种类及各种减阻措施。     

旋风分离器排灰与进、排气系统对分离性能的影响

在大量常温试验研究的基础上,着重研究了排灰与进、排气系统对旋风分离器性能的影响。提出了排灰斗与料腿尺寸不宜过小、串联时第二级旋风分离器入口气流要尽可能没有旋转等新观念。     

Determining Cyclone Particle Holdup by Pressure Drop for a CFB Boiler

An experimental study was conducted to assess the possibility of determining particle holdup by measuring the pressure drop of a conventional cyclone used in a circulating fluidized bed (CFB) boiler. It was found that within a wide range of inlet solid concentrations, i.e., 0.54–4.42 kg/kg‐gas, the cyclone pressure drop increased linearly with inlet solid concentration at a given gas velocity, while the pressure drop between the dust exit and the vortex finder of the cyclone remained almost constant. Since particle holdup increases virtually linearly with solid flow rate, the particle holdup in the cyclone can be derived from the cyclone pressure drop, and therefore, an equation set was proposed to calculate the particle holdup from the cyclone pressure drop.     

Cyclone Washer Adapted from an American‐Type Cyclone Separator

A modified cyclone washer was designed, fabricated, and its collection efficiency evaluated. This equipment consists of an American‐type cyclone separator with a triple cone and a spray nozzle was introduced into its cylindrical body. The study consisted of an experimental evaluation of the operating conditions at ambient and higher than ambient temperatures, varying chimney height and water flow rate, with the purpose of humidifying the dust. The collection efficiency of the cyclone washer was evaluated particles of micronized quartz with an average diameter of 7.48 μm and a density of 2.650 g/cm³. The amount of particles varied from 20–100 mg/m³ of air. An average efficiency of 97.07 ± 1.03 % was obtained with four spray nozzles, a chimney height of 0.645 m and 0.358 m³/s of gas.