半干法喷动床烟气脱硫技术最新进展

介绍了半干法粉未-颗粒喷动床（powder—particle spouted bed,PPSB）烟气脱硫技术的基本原理、主要优点、研究进展等,对影响脱硫效果的脱硫剂种类、脱硫剂粒径、钙硫摩尔比、气体停留时间、进口烟气温度与床层内脱硫温度、床层内气体湿度、进口SO2浓度及绝热饱和温差等因素的研究进展进行了综述。并与其它半干法脱硫技术进行了比较,说明其半干法粉未-颗粒喷动床烟气脱硫技术具有的优势和发展前景。     

双喷嘴矩形导流管喷动床脱硫性能的研究

针对半干法烟气脱硫方法,提出了一种新型的双喷嘴矩形导流管喷动床半干法烟气脱硫装置。在不同的钙硫摩尔比、静床层高度、表观气速、绝热饱和温差下,以消石灰为脱硫剂,研究了该装置的脱硫性能,并与未加导流管的双喷嘴矩形喷动床的脱硫性能进行了比较;研究了不同脱硫剂流量下导流管喷动床的喷动压降。实验结果表明:脱硫率与钙硫摩尔比、静床层高度成正比,与绝热饱和温差、表观气速成反比;喷动压降与脱硫剂流量成反比。并最终得出了实验条件下双喷嘴矩形导流管喷动床的最佳操作范围和脱硫率关联式。     

半干法烟气脱硫新技术--粉末颗粒喷动床技术

介绍国际上较流行的粉末颗粒喷动床技术(PPSB)半干法烟气脱硫新技术，阐述了PPSB的基本原理和实验方法以及相应的影响因素。说明该方法具有广泛的应用前景和良好的经济效益。     

喷动床技术在烟气脱硫中的应用及最新进展

从结构、特点等方面简介了近年来出现的几类喷动床,包括典型喷动床、多喷头喷动床、喷动-流化床、带导向管的喷动床、内循环喷动床等。对喷动床技术在烟气脱硫中的应用和最新进展进行了综述,叙述了粉末-颗粒喷动床半干法脱硫和喷雾-喷动床半干法烟气脱硫的基本原理、优缺点、影响脱硫的因素等;并对这两种脱硫方法的共性和个性进行了比较。说明了喷动床脱硫技术具有流态化性能好、传热传质效率高、脱硫效果好等突出优点,特别适合于中小型燃煤锅炉烟气脱硫。     

导流管的不同形式对喷动床颗粒循环量的影响

对于导流管喷动床,导流管的形式对颗粒物料的循环量影响不能忽略.研究了四种不同形式的导流管在导流管不同的安装高度、不同的床层料位高度以及不同的吹松气量对颗粒循环量的影响.结果表明:增加床层料位高度,在一定范围内增加导流管安装高度和吹松气量,会增大颗粒循环量;导流管形式对颗粒循环量影响至关重要.     

新颖环形喷动床颗粒喷动特性实验研究

一种新颖的环形喷动床由内外两个不同内径、同心的垂立圆筒组成,在环形空间底部设置多个喷口,在喷口两侧布置倾斜的导流板.研究颗粒在这种喷动床内的流动特性,探讨喷口结构、颗粒种类以及床内载料量对环形喷动床颗粒喷动特性的影响.实验结果表明:颗粒在环形喷动床内分为三个明显不同的区域,即颗粒填充移动区、密相喷动流化区以及稀相夹带区.当颗粒出现分区喷动后,随床内载料量的增多,填充移动区的高度维持不变,始终等于导流板的高度,而密相喷动区的高度不断增加.风量和颗粒种类对床层最大喷动量、密相喷动高度以及床层压力分布规律有着十分重要的影响.采用不同的喷口结构时,在相同的载料量下,直向喷口的密相喷动区高度更大,而且床内各测点的平均压力大于采用斜向喷口时的相应测点压力.     

双喷嘴矩形导流管喷动床喷动压降

引言 传统的柱锥形喷动床(CSBs)的应用受到一些因素的限制,例如处理物料能力、起始压力大及难以放大等,为此,Romankov等[1]最早提出了长方形截面的矩形喷动床结构,来克服CSBs的缺点.此后,Rocha等[2]用矩形喷动床进行了片剂包衣的研究.     

二维导流管喷动床离散颗粒动力学模拟

采用离散单元法(DEM)-计算流体力学(CFD)双向耦合数值方法对二维导流管喷动床进行了模拟,颗粒的运动通过DEM模型描述,而气体的运动用Navier-Stokes方程进行求解,气体和固体颗粒之间的相互作用通过曳力形式传递。文中将DEM和边界元方法(BEM)结合起来解决颗粒在具有复杂边界设备内的运动。通过采用BEM+DEM-CFD相结合的方法进行模拟计算,得到了喷动床的最小喷动速度,研究了不同表观气速下床内的流型,得到了二维导流管喷动床的床层压降与表观气速的关系,统计分析了喷射区、环隙区内颗粒的运动速度和相应的空隙率,全面地描述了二维导流管喷动床内的气固流动特征。     

带导流管液固喷动床的最小喷动速度研究

在截面为矩形有机玻璃喷动床内,使用四种粒径的窄筛分球形玻璃珠,以常温水作为喷动和辅助液体。综合考虑床体的几何尺寸、操作参数以及液体和颗粒的物性特征,系统研究带导流管喷动床的最小喷动速度,得出最小喷动速度的经验公式,为设计和操作提供参考。     

半干法烟气脱硫技术研究现状及进展

本文综述了半干法烟气脱硫技术的研究现状，说明了半干法脱硫技术不同脱硫方法的原理及特点，指出了半干法脱硫技，术涛在问题，并对其今后的发展趋势进行了分析，指出投资少，运行费用低，脱硫率高，无污染的脱硫工艺是今后半干法脱硫技术的发展趋势。     

Removal of SO2 from flue gas using a new semidry flue gas desulfurization process with a powder-particle spouted bed

A spouted bed of binary particle mixture was applied to a low temperature desulfurization process in order to develop a new type of semidry flue gas desulfurization (FGD) technology. We investigated the effects of operating parameters, such as type of SO₂ sorbent, diameter of SO₂ sorbent particles, apparent residence time of gas in the bed, approach to saturation temperature and Ca/S molar ratio, on SO₂ removal in a bench-scale powder-particle spouted bed. We also investigated the utilization rate of SO₂ sorbent and ways to enhance the efficiency of SO₂ removal and SO₂ sorbent utilization. The experimental results showed that SO₂ removal is significantly affected by the approach to saturation temperature and Ca/S molar ratio, and that a high SO₂ removal efficiency and effective sorbent utilization can be obtained under appropriate operating conditions. Thus, this new simple process of flue gas desulfurization is highly efficient and has little impact on the environment.     

Study of the hydrodynamics within a draft tube spouted bed system

Two dimensional Darcy and Ergun models are used to describe the hydrodynamics within the annulus of a spouted bed equipped with a draft tube. Experimental pressure and stream function data for water spouting are shown to be in good agreement with theoretical predictions. Verification of a general spout-annulus interfacial boundary condition is also established and it is shown that the entry region below the draft tube functions as a classical spouted bed. In addition, an experimental procedure for determining the location of the spout-annulus interface is presented. Fluid residence time distributions are calculated for a few cases of practical interest.     

Hydrodynamics of a gas-driven gas-liquid-solid spouted bed with a draft tube

A cylindrical gas-liquid-solid spouted bed, driven exclusively by gas flow, has been developed with a high potential for use in biochemical processes, such as a biological wastewater treatment. A plexiglass column with a 152 mm inner diameter was used in combination with a 53 mm inner diameter plexiglass draft tube. Three particle types were studied with densities ranging from 1044 kg/m³-1485 kg/m³ and average particle sizes ranging from 0.7-2.5 mm. Four flow regimes were observed when increasing the gas velocity, including fixed bed, semispouted bed, full spouted bed, and internal circulating fluidized bed. The transition gas velocities between those regimes were experimentally measured and termed as minimum spouting velocity, full spouting velocity, and minimum circulating velocity, respectively. A measurement of the downward particle flux in the annulus was used to identify the minimum spouting velocity, while the particle velocity and dense phase retraction in the annulus were monitored for the full spouting and minimum circulating velocities. All regime transition velocities increased with more dense particles and longer draft tubes. The minimum spouting velocity and full spouting velocity were not affected when varying the nozzle-tube gap, while the minimum circulating velocity increased with longer nozzle-tube gaps. Experiments without a draft tube were carried, though the spouting stability was significantly reduced without the draft tube.     

喷雾干燥半干法烟气脱硫效率主要影响因素的实验研究

为提高半干法烟气脱硫效率,通过改变喷嘴级数、脱硫剂类型和增加添加剂等,在自主设计和搭建的热态实验平台上,对半干法烟气脱硫进行了实验研究。结果表明：增加喷嘴级数可有效提高脱硫效率;双级系统脱硫效率在一、二级喷嘴供浆量各占60%和40%时达到最高,比相同工况下单级系统可提高15.2%;烟气温降和SO₂脱除主要发生在浆液雾化区;增加添加剂能有效地提高系统的脱硫效率,添加剂浓度小于0.8 g·L^-1时,脱硫效率随其浓度呈线性增加,作为添加剂NaOH较NaCl效果更为明显。     

带导流管多层流化床流体力学特性实验研究

多层流化床的应用范围受操作可调性和稳定性等因素限制。在改变传统筛板结构的基础上,研究了传统穿流板多层流化床和导流管多层流化床床层压降随表观气速和进料速率的变化规律,实验结果表明,导流管多层流化床不仅大幅减小了床层压降、提高了床体处理能力和可调范围,而且也改善了物料的流化质量。此外,当料层达到一定高度时,导流管多层流化床还具有喷动流化床的特性,同时导流管还具有溢流物料的作用,进一步加大了气固传质效率和床体处理能力。在流体力学分析的基础上,推导出导流管多层流化床床层压降的关联式,得到了床层压降随进气气速和进料速率的关系,与实验数据基本吻合。     

伊泰锅炉循环流化床烟气脱硫技术研究

为提高烟气脱硫效率,在分析循环流化床脱硫工艺的基础上,根据煤质分析,选取了系统的烟气设计参数和脱硫剂参数并对脱硫效率进行分析。结果表明,循环流化床烟气脱硫技术与炉内喷钙法相结合可以达到90%的脱硫效率,SO2的排放浓度小于200 mg/m3,可以满足《锅炉大气污染物排放标准》的相关要求。与湿法脱硫技术相比,循环流化床烟气脱硫技术具有设备紧凑,投资少,占地小,特别适用于现有机组的改造工程,脱硫剂利用效率高,脱硫产物为干灰,不会产生二次污染等优点。但循环流化床烟气脱硫技术也存在着脱硫效率较湿法脱硫技术偏低,对锅炉负荷的变化适应性差,运行控制要求较高等不足。     

Prediction of pressure drop and minimum spouting velocity in draft tube conical spouted beds using genetic programming approach

The smart method of genetic programming (GP) is used to predict the operating pressure drop (ΔP_s) and the minimum spouting velocity u_ms for conical spouted beds (CSBs) equipped with nonporous draft tubes. Accordingly, six dimensionless variables have been taken as model inputs, including crucial parameters associated with the bed and tube geometric and operating conditions. Two general correlations comprising almost all constitutive and operating variables have been derived for the first time by the GP approach. Both ΔP_s and u_ms values predicted by the GP technique are in a fair agreement with the values corresponding to the experiments, with average absolute relative errors (AARE) of 18.9 and 19.9 %, respectively. The results of the proposed correlations show that the GP method is a powerful tool to make reasonable estimates.     

Side-outlet spouted bed with draft tube: Effect of varying the position of the outlet

The vector form of the Ergun equation was used to numerically predict gas phase streamlines, residence time distributions, chemical conversions and pressure drops in the annulus of a side-outlet spouted bed with an internal draft tube. By varying the position of the side-outlet, it was demonstrated that there exists an optimum location for this outlet at which conversion is a maximum and which shows a greatly improved gas phase residence time distribution in the annulus compared with a conventional spouted bed unit.