260t/h循环流化锅炉炉内脱硫效率分析

以一台石油焦与煤混烧260t/h的循环流化锅炉为对象,进行了炉内脱硫性能试验,分析了焦煤配比、Ca/S物质的量比、床温、石灰石粒径、飞灰再循环系统等对锅炉炉内脱硫效果的影响。试验表明,该锅炉控制床温在850~900℃,Ca/S比为2.4~3.2,石灰石中位径0.5mm,脱硫效率较高;投用飞灰再循环系统能够有效降低SO2排放浓度。     

钙基脱硫剂增压喷动流化床煤气化炉的炉内脱硫

用石灰石作为脱硫剂在热输入0.1 MW的加压喷动流化床试验台上进行了煤部分气化过程中的炉内脱硫试验研究。系统地考察了温度、压力、钙基脱硫剂粒径、钙硫摩尔比等参数对脱硫效率的影响。试验结果如下：随着温度的升高、压力的增加,脱硫效率均提高,但增长幅度减缓。随钙硫摩尔比的增加,脱硫效率提高,但当Ca/S（摩尔比）＝2后,继续增大Ca/S,脱硫效率提高有限。脱硫剂粒径减小,脱硫效率提高。     

燃煤流化床锅炉炉内脱硫工业化技术研究

采用石灰石作为燃煤循环流化床锅炉炉内脱硫剂,当石灰石粒径为1.5~2.0 mm,流化床锅炉炉内钙硫摩尔比为2.7,床温为880℃时,尾气中的SO_2排放浓度为173 mg/m~3,无需进行锅炉尾气二次脱硫即可满足《锅炉大气污染物排放标准》要求,同时,炉内脱硫反应对锅炉效率的影响甚微,锅炉运行综合经济及环保效益最佳。     

石灰石特性对1MW循环流化床SO_2排放影响的试验研究

为实现石灰石在循环流化床锅炉炉内脱硫过程的高效利用,在1 MW循环流化床试验平台中,考察了石灰石给料方式、粒径、Ca/S摩尔比对脱硫效果的影响;试验结果表明,细颗粒石灰石A的脱硫效率仅为67.4%,远低于粗颗粒石灰石B的96.6%,但继续增大石灰石粒径,则脱硫效率开始下降,适宜的石灰石粒度范围可以显著提高脱硫效率;Ca/S摩尔比从1.7增至2.5的过程中,脱硫效果提升接近一倍,但继续增至3,则脱硫效果基本不变;通过选择合适的石灰石粒径及Ca/S摩尔比,可将SO_2平均排放浓度降至39.3 mg/m~3,有望最终实现"超低排放"的目标。     

基于多经济因素的FGD联合脱硫试验

大型循环流化床发电机组在烟气污染物超低排放的限制下，仅靠炉内脱硫难以满足要求，需在炉外联用烟气脱硫系统，二者脱硫有机匹配能够降低综合脱硫成本。为确定电厂运行过程中两级联合深度脱硫最佳脱硫分配比例，实现满足排放标准下最低的脱硫成本。根据多种成本因素，建立技术经济计算模型分析不同炉内钙硫比(物质的量之比)对脱硫分配比例的影响及主要成本因素，并研究不同石灰石价格和厂用电价在不同炉内钙硫比下对综合脱硫成本的影响。结果表明，炉内钙硫比为1.0、1.1～1.5、1.6、1.7～2.1时，最佳炉内脱硫份额分别为70%、60%、85%和80%;炉内脱硫对锅炉热效率有较大影响，且钙硫比越高影响越大，当炉内钙硫比超过2.0时，炉内脱硫热损失会降低锅炉热效率；炉内脱硫的主要成本因素是石灰石粉和运行电耗成本，石灰石/石膏湿法烟气脱硫的主要成本因素为石灰石浆液和吸收塔运行电耗成本，且随脱硫分配比例不同有明显变化；不同的石灰石价格和厂用电价在不同炉内钙硫比下具有不同的最佳脱硫分配份额。     

纳米级石灰石钙基脱硫试验研究

考虑到纳米微粒的粒径小,比表面大的特点,在一维热态试验台上,研究了纳米级钙基吸着剂脱硫过程.结果表明,纳米级石灰石普遍具有很好的脱硫效果,不同纳米石灰石,由于其比表面积、粒径以及内部成份、结构等的不同,脱硫率明显不同;粒径,温度和SO2浓度是影响脱硫的关键因素,在最佳温度1000℃、粒径为100nm,Ca/S=1.5和SO2浓度为2000ppm的条件下,其脱硫率可达90%以上.     

筛板塔在湿法烟气脱硫中的应用

为考察筛板塔在湿法烟气脱硫中的脱硫效果.以石灰石料浆做脱硫剂,在筛板塔反应器中进行了湿法烟气脱硫实验.考察了液气比(L/V)、入口烟气SO2质量浓度、钙硫比(m(Ca):m(S))对脱硫效率的影响.结果表明,脱硫效率随着液气比的增加而增大,在液气比为2.2时,筛板塔脱硫效率可达到68%;随着进口 SO2质量浓度的增加,脱硫效率随之下降;且随着钙硫比的增加,脱硫效率增大.实验条件下,筛板塔以较小的液气比可以取得较高的脱硫效率,对降低湿法烟气脱硫成本有一定的意义.     

循环流化床锅炉高效炉内脱硫理论和关键技术

低成本、无废水、系统简单的炉内脱硫技术是循环流化床锅炉实现洁净燃烧有效和优选途径之一。由于影响因素众多及试验数据分散,目前仍缺少具有普遍适用的脱硫效率预测手段,对于实际应用过程中脱硫效率随Ca/S比增加出现下降现象的原因还未给出合理解释,单纯Ca/S比也无法反映实际参与脱硫的石灰石量,因而难以描述炉内石灰石的脱硫规律。为了探索决定炉内石灰石脱硫效率的本质,以锅炉炉内物料运动、分布规律为基础,通过探讨入炉石灰石随炉内物料运动及反应变化情况,对循环流化床炉内脱硫进行深入分析,提出"石灰石有效存有量"的概念,并根据灰平衡原理建立数学模型。通过与不同规模的燃烧颗粒煤和煤泥的工业循环流化床锅炉试验数据进行比较,验证了该模型的有效性。研究结果表明,实际决定炉内脱硫效率的最重要因素是"石灰石有效存有量",该理论的建立为有效提高炉内脱硫效率提供了依据,由此得出实现炉内高效脱硫的关键在于:①优化石灰石粒度分布以有效提高外循环石灰石量和石灰石炉内的停留时间;②合理排渣以减少石灰石有效存有量的损失;③提高气-固接触效率以充分利用有效石灰石的活性。     

基于半干法NGD脱硫技术的SO2超低排放试验研究

随着环保形势的日益严峻,国家对中小型燃煤工业锅炉的烟气污染物治理也提出了超低排放要求。采用半干法烟气脱硫技术是解决中小型燃煤锅炉尾部烟气SO_2污染问题并实现超低排放的有效途径之一。作为一种新型半干法烟气脱硫技术,NGD脱硫采用锅炉自生高钙粉煤灰作为脱硫剂,有效降低了脱硫剂运行成本。为验证该技术的SO_2超低排放效果和脱硫剂使用经济性,以神东某锅炉房配套40 t/h煤粉锅炉NGD脱硫装置为研究对象开展工业试验,同时考察了装置运行稳定性以及关键因素对脱硫效果的影响。试验结果表明,NGD反应器进出差压平均值约1 100 Pa,未出现曲线急剧上升或下降的现象,说明装置总体运行稳定性较好。外加适量Ca(OH)_2后,NGD脱硫装置的SO_2平均排放浓度(9%O_2)小于35 mg/Nm~3,达到超低排放效果。计算得到外加Ca(OH)_2与反应器入口SO_2的钙硫摩尔比n(Ca/S)=0. 9,由于主要利用锅炉自生粉煤灰中的活性钙,外加Ca(OH)_2量低于同类半干法烟气脱硫技术。研究发现,装置脱硫效率随增湿水量的增加而升高;在测试工况下,锅炉自生粉煤灰掺混少量Ca(OH)_2后,脱硫率由70%提高到90%以上。     

循环流化床锅炉石灰石消耗分析控制

循环流化床锅炉一般采用炉内喷石灰石粉脱硫。粒径适当的石灰石粉和良好的锅炉燃烧工况对保持高效的脱硫效率,提高锅炉经济运行至关重要。本文对洛阳石化循环流化床锅炉进行研究,通过分析石灰石粉性质、工艺燃料结构及实际SO2排放量,提出控制石灰石粒径、完善监督检测措施、提高设备运行稳定性及优化运行等降低石灰石消耗措施,降低成本,提高经济效益。     

高硫煤在循环流化床燃烧室内的脱硫研究

就某高硫煤在1MWth循环流化床（CFB）燃烧室中的脱硫性能进行了试验研究和分析。试验结果发现在钙硫摩尔比为2.2时可达到90%以上的脱硫效率，石灰石对脱硫程度的影响与加入炉内的石灰石量大小有关，CFB炉内物料石灰石浓度是评价石灰石脱硫效率的重要指标，炉膛上部的脱硫状况很大程度可能与SO2的最终排放浓度有关。     

300 MWCFB锅炉提高SO_2超低排放经济性试验研究

为了提高锅炉机组SO_2超低排放的经济性,在某300 MWCFB锅炉开展了实炉试验,研究了CFB锅炉炉内干法脱硫与CFB-FGD脱硫相结合的两级联合脱硫技术。结果表明:通过理论分析和试验室检测可优选出炉内干法脱硫和CFB-FGD的最佳脱硫剂品种。CFB锅炉运行参数中负荷的变化同时影响两级脱硫效率。随着锅炉负荷的升高,床温和脱硫塔入口温度均呈现上升趋势。床温的升高降低了炉内脱硫效率,脱硫塔入口温度的上升提高了CFB-FGD脱硫效率。按照推荐的石灰石和生石灰物化参数及两级脱硫系统匹配方式运行,锅炉净烟气SO_2浓度满足超低排放限值要求,炉内干法脱硫与CFB-FGD脱硫剂耗量均下降,提高了SO_2超低排放的经济性,降低了脱硫成本。     

Evaluation of the performance of a commercial circulating fluidized bed boiler by using IEA-CFBC model: Effect of primary to secondary air ratio

The performance of a commercial circulating fluidized bed boiler in the Yeosu thermal power plant, which has been operating since October 2011 by KOSEP, has been evaluated by using the IEA-CFBC model. To validate the calculation procedure of the model, the calculated results were compared with the operation values such as the temperatures, pressures, emissions of SO₂ and NO, particles size distribution and unburned carbon fraction of the CFB boiler at a certain actual condition. The calculated results were comparable to measured values from the CFB boiler, so these could conform to acceptable formats with a good accuracy. The effect of the primary to secondary air ratio on the performance of the CFB boiler was also determined. As the primary air ratio increased, the solid fraction and temperature in the furnace freeboard increased. As a result, the solid circulation rate and the heat absorption in the furnace increased with increasing the PA ratio. In the case of the amount of heat absorption, the wall tube of the furnace absorbed much more generation heat in the furnace than the wing wall tube. The SO₂ emission decreased due to increase of the limestone hold up in the furnace, and the combustion efficiency somewhat increased with increasing the PA ratio. Therefore, from these results, we could expect to control the boiler performance such as the furnace temperature, steam temperatures of superheater or reheater, gaseous emissions and combustion efficiency through the changing the PA ratio of the CFB boiler.     

Sulfur fate during bituminous coal combustion in an oxy-fired circulating fluidized bed combustor

To clarify the sulfur transformation behavior during oxy-fired circulating fluidized bed (CFB) combustion, experiments on SO₂ emission characteristics were carried out in a 50 kWth CFB combustor. Results show that SO₂ emission is quite dependent on the bed temperature in different atmospheres without limestone injection. With Ca/S=2.5, SO₂ emission in 21%O₂/79%CO₂ atmosphere is smaller than that in air atmosphere, but SO₂ emission decreases with the increase of O₂ concentration. The calcium forms in the ash prove the combination of calcination/carbonation and direct sulfation mechanism of limestone under oxy-combustion conditions. And the desulfurization efficiency of limestone (as deducting the self-retention efficiency from the total sulfur removal efficiency) increases from 40% to 52% as the O₂ concentration increases from 21% to 40%.     

以煤焦混合物为燃料的循环流化床锅炉SO2排放特性

在工业运行的410 t·h^-1循环流化床锅炉上进行烟煤、70％烟煤＋30％石油焦和50％无烟煤＋50％石油焦的燃烧试验,研究了运行参数对SO₂排放特性的影响。结果表明,3种燃料均能达到良好的燃烧效果,炉内温度场分布均匀。在相同燃烧条件下,不同燃料SO₂排放量与其中的含硫量呈正相关关系。SO₂排放量随温度的升高先减小后增大,存在最佳脱硫温度;随钙硫比的增大而减小;随过量空气系数的增大而减小;随飞灰再循环量的增大而减小。对于不同种类的石灰石,大比表面积和高比孔容积的石灰石对SO₂有较好的脱除效果。考察了燃用不同燃料的最佳温度、钙硫比和过量空气系数,阐述了飞灰再循环和石灰石微观结构在循环流化床锅炉脱硫中的机理和作用,以期对循环流化床的设计和运行工作提供指导。     

流化床内煤着火特性实验研究

为了对当前大量应用的带有床下启动燃烧器 CFB锅炉的启动运行提供指导 ,以及为从事循环流化床技术和煤燃烧理论研究提供参考 ,在电加热的小型流化床燃烧系统上 ,采用热烟气炉下点火的方式来研究煤粒在流化床内的燃烧特性 .测定了福建龙岩无烟煤的着火特性 ,分析了粒径、床温对着火点的影响 .并提出了煤颗粒在流化床内着火点测定的实验规范 .     

粒径对福建无烟煤在CFB锅炉中燃尽的影响

建立了福建无烟煤细颗粒燃烧模型,计算了其在容量35 t/h循环流化床锅炉炉膛内的燃尽时间和一次通过炉膛的停留时间,分析了不同粒径煤颗粒在不同燃烧温度和不同烟气流速时在CFB锅炉内的燃尽时间和停留时间的变化差异. 实验研究了福建无烟煤粒径对飞灰碳含量的影响及燃尽的影响. 结果表明,细煤颗粒的燃尽时间与停留时间均随粒径增大而增长,但燃尽时间增幅更明显,颗粒一次通过炉膛完全燃尽的临界粒径约为0.15 mm;粒径越大的颗粒其停留时间和燃尽时间对烟气流速和燃烧温度变化越敏感;无烟煤入炉粒径明显影响CFB锅炉飞灰含碳量,选用粒度为3~8 mm的偏粗颗粒为宜.     

Coal combustion characteristics in a pressurized fluidized bed

The characteristics of emission and heat transfer coefficient in a pressurized fluidized bed combustor are investigated. The pressure of the combustor is fixed at 6 atm. and the combustion temperatures are set to 850, 900, and 950 °C. The gas velocities are 0.9, 1.1, and 1.3 m/s and the excess air ratios are 5, 10, and 20%. The desulfurization experiment is performed with limestone and dolomite and Ca/S mole ratios are 1,2, and 4. The coal used in the experiment is Cumnock coal from Australia. All experiments are executed at 2 m bed height. In this study, the combustion efficiency is higher than 99.8% through the experiments. The heat transfer coefficient affected by gas velocity, bed temperature and coal feed rate is between 550-800 W/m² °C, which is higher than those of AFBC and CFBC. CO concentration with increasing freeboard temperature decreases from 100 ppm to 20 ppm. NO_x concentration in flue gas is in the range of 5-130 ppm and increases with increasing excess air ratio. N₂O concentration in flue gas decreases from 90 to 10 ppm when the bed temperature increases from 850 to 950 °C.     

Combustion and De-SOx behavior of high-sulfur coals added with calcium acetate produced from biomass pyroligneous acid

This paper first aims to evaluate the possibility of synthesizing organic calcium through the use of pyroligneous acid and raw limestone. The factors affecting this reaction were investigated including the particle size of limestone, the type of pyroligneous acid and reaction conditions as well. Secondly, two low-rank coals were mixed with the calcium-enriched pyroligneous acid to evaluate the possibility of desulfurization in the combustion furnace. The soluble calcium within pyroligneous acid is in the form of calcium acetate having a low decomposition temperature around 400 °C, far lower than that of raw limestone being about 700 °C. Due to its solubility, calcium within pyroligneous acid was loaded readily on the coals, forming the ultrafine particles in the impregnated coal matrix. During coal combustion, the loaded calcium underwent quick decomposition prior to char combustion and subsequently, the formed ultrafine calcium oxide captured the evolved sulfur oxide. Around 85% desulfurization efficiency was achieved for coal combustion. S/Ca molar ratio around 1.0 was formed for the particles less than 1.0 μm, whereas it decreased gradually with the increasing particle size.     

新型半干法流化床烟气脱硫技术的研究

提出了一种新型的半干法流化床烟气脱硫技术。研究了钙硫比、饱和接近度与脱硫剂活性等因素对脱硫效率的影响,并进行了机理分析。结果表明,钙硫比、饱和接近度与脱硫剂的活性对脱硫效率影响非常明显;石灰石的脱硫效率虽然不及消石灰,但由于脱硫剂停留时间长,气、液、固三相接触好的特点,以及可以对石灰石进行研磨与活化,因此,利用石灰石作脱硫剂的半干法流化床烟气脱硫工艺完全可以达到理想的脱硫效率,同时也可以保持较好的经济性。