Determination of thermal parameters for waste liquid and gas fluidized-bed incinerator

Equations are established for calculation of dense and dilute phase zone combustion temperatures, quantity of auxiliary fuel and thermal efficiency for a fluidized bed incinerator with coal burnt as auxiliary fuel, waste liquid burnt in dense phase zone and waste gas burnt in dilute phase zone while there is a heat transfer, thereby providing theoretical basis for design of waste liquid and gas fluidized bed incinerators.

NO_x emission from incineration of organic hazardous liquid waste containing hexamethylendiamine in fluidized bed

Experiments have been conducted to investigate  NO x concentration profiles along bed height and influences of temperature and excess air on  NO x emission in the range from 700 ℃ to 900 ℃, when waste water containing 5% Hexamethylenediamine incinerated in a bench scale hot fluidized bed. The testing results indicate that the concentration of NO 2 is larger than that of NO along bed height except in the freeboard at 900 ℃, where NO, NO 2 concentrations are zero. Temperature and excess air play significant role on  NO x emission. With increasing in temperature the  NO x emission decreases very rapidly in the range from 700 ℃ to 900 ℃. With increasing in excess air,  NO x emission increases considerably at 700 ℃, but it is almost independent of excess air at 800 ℃,and at 900 ℃  NO x emission is zero indicating that NH 2 from NH 2(CH 2) 6NH 2 has strong effect on de  NO x with increasing in temperature and excess air.  NO x concentration profiles decrease progressively with bed height because of reduction of  NO x by NH 2. The mechanism of  NO x formation and destruction is presented in the paper.

Novel Technology and Products: Fluidized Bed Incineration and Energy Recovery for Waste Disposal——Developed by the Institute for Thermal Power Engineering, Zhejiang University

The waste referred to includes solid waste and sludge. Solid waste is mainly from urban garbage and industrial waste. Sludge is from water treatment factories, paper mills, chemical factories, pharmaceutical factories, rivers and lakes. The waste and sludge are very harmful to water organisms, human health and drinking water, and directly affect the environment. Sludge and waste also occupy large areas of land. There are several methods to treat waste and sludge, such as burial, chemical treatment and incineration. Incineration is more effective than the

Polychlorinated dibenzo-p-dioxins and dibenzofurans in flue gas emissions from municipal solid waste incinerators in China

Polychlorinated dibenzo-p-dioxins and furans （PCDD/Fs） emissions in flue gas from two types of municipal solid waste incinerators （MSWIs） most commonly used in China were investigated in this study. The selected incinerators include two grate-type MSWIs： MSWI-A （350 t/d） and MSWI-B 050 t/d）, and two fluidized bed MSWIs： MSWI-C （400 t/d） and MSWI-D （400 t/d）, which are all equipped with semi-dry lime scrubber and bag filter except MSWI-D equipped with cyclone and wet scrubber （WS） as air pollutant control device （APCD）. Results indicated that the emission concentration and the international toxic equivalents （I-TEQs） of the PCDD/Fs from the stacks were in the range of 1.210-10.273 ng/Nm^3 and 0.019-0.201 ng I-TEQ/Nm^3, respectively. They were greatly lower than the emission regulation standard of PCDD/Fs in China （1.0 ng I-TEQ/Nm^3）. However, only the PCDD/Fs emission level from MSWI-C was below 0.1 ng I-TEQ/Nm^3. Although the homologue profiles were distinct, the contributions of the 2,3,7,8-subsituted congeners to the total I-TEQ were similar among all the investigated MSWIs. Two major 2,3,7,8-substituted congeners, 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD, account for 47% and 9% （average values） of the total I-TEQ values, respectively. The correlation between PCDD/Fs levels and composition of flue gas was also discussed.

Incineration of kitchen waste with high nitrogen in vortexing fluidized-bed incinerator and its NO emission characteristics

Some municipal solid waste （MSW） can be used as the fuel. Combustion of MSW with high nitrogen content is successfully conducted in a lab-scale vortexing fluidized-bed incinerator （VFBI）. Pigskin with 16.5 wt.% nitrogen content was used to simulate the high nitrogen content kitchen waste, and silica sand was used as the bed material. The effects of operating conditions, such as the bed temperature, freeboard temperature, excess oxygen ratio, and static bed height on the CO and NO concentrations at the exit of combustor and cyclone were investigated. The experimental results show that the freeboard temperature is the most important factor for CO emission. The order of operating conditions impact on the NO emission is： （1） excess oxygen ratio; （2） bed temperature; （3） freeboard temperature; and （4） static bed height. Utilizing cyclone can significantly reduce the CO emission concentration when the CO concentration released from the freeboard is higher than 50 ppm. On the other hand, the cyclone has no significant effect on the NO emission. Despite having high nitrogen content, a low conversion from fuel-N to NO was attained. Compared with other types of combustors, VFBI reduces the CO and NO emission concentrations much better when burning MSW with high nitrogen content.

Pollutant emission characteristics of rice husk combustion in a vortexing fluidized bed incinerator

Rice husk with high volatile content was burned in a pilot scale vortexing fluidized bed incinerator. The fluidized bed incinerator was constructed of 6 mm stainless steel with 0.45 m in diameter and 5 m in height. The emission characteristics of CO, NO, and SO2 were studied. The effects of operating parameters, such as primary air flow rate, secondary air flow rate, and excess air ratio on the pollutant emissions were also investigated. The results show that a large proportion of combustion occurs at the bed surface and the freeboard zone. The SO2 concentration in the flue gas decreases with increasing excess air ratio, while the NOx concentration shows reverse trend. The flow rate of secondary air has a significant impact on the CO emission. For a fixed primary air flowrate, CO emission decreases with the secondary air flowrate. For a fixed excess air ratio, CO emission decreases with the ratio of secondary to primary air flow. The minimum CO emission of 72 ppm is attained at the operating condition of 40% excess air ratio and 0.6 partition air ratio. The NOx and SO2 concentrations in the flue gas at this condition are 159 and 36 ppm, which conform to the EPA regulation of Taiwan.

烧结烟气的循环流化床焚烧处理方法

烧结烟气是钢铁生产的烧结工序产生的废气,含NO_(x)、SO_(2)、二噁英、挥发性有机物等污染物成分。用烧结烟气替代燃煤循环流化床锅炉空气以焚烧处理,既能有效资源化利用废气中CO和余氧,又能借助循环流化床中脱硫脱硝设备与高温环境,将烧结烟气中SO_(x)和NO_(x)等污染物与燃煤产生的污染物一并去除,有望成为高效的烧结烟气一体化污染物处理技术。然而,目前燃煤循环流化床燃烧背景下烧结烟气中二噁英、挥发性有机物等污染物脱除的研究尚不足。针对该问题,先通过化学反应动力学模拟,研究烧结烟气作为助燃剂燃烧过程,发现燃烧过程中产生的氢等自由基在二噁英分解过程中发挥重要作用,燃烧反应温度提高能显著促进二噁英及挥发性有机物的脱除,而燃尽烟气的余氧量降低对二噁英的脱除也有较显著促进作用。通过计算颗粒流体动力学的方法,模拟以烧结烟气为助燃剂的燃煤循环流化床锅炉运行情况,发现燃烧过程流态化情况好,烧结烟气中低浓度CO基本燃尽,旋风分离器出口CO质量浓度约100 mg/m^(3),燃烧温度达到去除污染物的要求,验证了将烧结烟气作为燃煤循环流化床锅炉中助燃剂的可行性。在唐山某钢铁企业开展了烧结烟气的循环流化床焚烧方法工程验证,测试发现低低温省煤器出口处烟气二噁英脱除率超过99.5%,低至0.0057 ng TEQ/m^(3),CO质量浓度低至108 mg/m^(3),此外烟气中NOx和SO2质量浓度低至38、24 mg/m^(3),满足超低排放要求。工程验证证实循环流化床烧结烟气一体化焚烧处理技术有效。

青浦污泥干化焚烧项目设计运行分析

青浦区污泥干化焚烧项目Ⅰ期工程设计处理规模为300 t/d(含水率为80%),处理青浦区的10座污水处理厂的脱水污泥。项目核心工艺采用“薄层干化+鼓泡式流化床”干化焚烧技术,设2条生产线,设置余热锅炉回收热量生产污泥干化所需的蒸汽,配套“炉内脱硫+选择性非催化还原(SNCR)脱硝+静电除尘+小苏打干法脱酸+活性炭喷射+布袋除尘+湿式脱酸+烟气再热”组合烟气净化系统;臭气按源头有效封闭、分区分类收集、分质处理和末端组合处理的原则进行,系统产生的混合废水与脱酸废水进行分类收集、分质处理。该项目克服了类似“孤岛”建设污泥项目的困难,整体运行稳定、环保达标,对类似项目具有一定的参考价值。

UASB和MBR组合工艺处理生活垃圾焚烧发电厂渗滤液的研究

上升式厌氧污泥床(Upward Anaerobic Sludge Bed,UASB)和膜生物反应器(Membrane Bio-Reactor,MBR)是目前较为流行的渗滤液处理技术,其组合工艺可有效处理渗滤液。生活垃圾焚烧发电厂可以综合运用两种技术,提升渗滤液处理能力,降低渗滤液对环境的危害。本文结合生活垃圾焚烧发电厂渗滤液产生量与设计进出水水质,设计渗滤液处理工艺,确定关键构筑物和设备参数,然后开展应用案例分析,验证渗滤液处理效果。经现场测试,UASB和MBR组合工艺可有效降低渗滤液的氨氮浓度,明显改善出水水质。

含盐废液焚烧过程中的废气排放控制策略探究

本研究旨在探讨含盐废液焚烧过程中的废气排放控制策略,以实现废弃物的无害化处理和资源化利用。通过分析焚烧技术的基本原理、关键技术以及废气排放控制的理论基础,本研究采用了稀释配合中和调节的预处理方法,以流化床焚烧炉作为焚烧设备,并对焚烧过程的参数进行了严格控制。结果表明,通过优化燃烧条件和烟气净化技术,能够有效降低烟气中有害物质的排放浓度,减少环境污染。此外,废盐处理与回收技术的应用有助于提高资源利用效率。

鼓泡流化床焚烧炉的热力学稳定性评估及市政污泥的入炉策略

市政污泥成分复杂,脱水后的市政污泥性质通常呈现一定的波动性,并影响市政污泥焚烧炉运行的稳定性。通过建立绝热型鼓泡流化床焚烧炉的热量平衡,从污泥热值及含水率波动、燃尽率、停留时间、焚烧炉自身抗热值波动能力、流化风温度和进料负荷的调节潜力等多个方面分析了市政污泥焚烧炉的热力学稳定性,结果表明,市政污泥焚烧炉对进料污泥性质较为敏感,而焚烧炉的自身稳定性相对有限,对热值的适应弹性空间约为6%。对于来源复杂的市政污泥,以收到基热值为基准,采取炉前分类及炉内混合对于达到相对稳定的进泥条件是必要的。

Volatilization of heavy metals during incineration of municipal solid wastes

Incineration experiments with MSW, which had been impregnated with heavy metals, were presented to obtain information on the volatilization behavior of the elements cadmium(Cd), lead(Pb), and zinc(Zn) under different conditions. Experiments were carried out in a bubbling fluid bed system connected to a customized inductively coupled plasma optical emission spectroscopy(ICP-OES) for analyzing metals in the flue gas. The results indicated that the combustion temperature, the gas atmosphere, and the chlorine content in the flue gas could affect the volatilization behavior of heavy metals. In the fluidized bed combustion, a large surface area was provided by the bed sand particles, and they may act as absorbents for the gaseous ash-forming compound. Comparer with the metals Cd and Pb, the vaporization of Zn was low. The formation of stable compounds such as ZnO·Al 2O 3 could greatly decrease the metals volatilization. The presence of chlorine would enhance the volatilization of heavy metals by increasing the formation of metal chlorides. However, when the oxygen content was high, the chlorinating reaction was kinetically hindered, which heavy metals release would be delayed.

Performance evaluation of circulating fluidized bed incineration of municipal solid waste by multivariate outlier detection in China

This first nationwide survey was conducted to evaluate the overall performance of the circulating fluidized bed （CFB） incineration of municipal solid waste （MSW） in 2014-2015 in China. Total 23 CFB incineration power plants were evaluated. The data for monthly average flue gas emission of particles, CO, NOx, SO2 and HCl were collected over 12 consecutive months. The data were analyzed to assess the overall performance of CFB incineration by applying the Mahalanobis distance as a multivariate outlier detection method. Although the flue gas emission parameters had met the Chinese national emission standards, there were 11 total outliers （abnormal behavior） detected in 6 out of 23 CFB incineration oower olants from the oersoective of the MSW incineration performance. The results demonstrate that it is more important for a better perlbrmance of CFBs to reduce the lrequencles ot the MSW load changes, rather than the magnitudes of the MSW load changes, particularly reducing the frequencies in the range of 10% and more of the load changes, under the same and stable conditions. Furthermore, the overloading occurs more often than the underloading during the operation of the CFB incineration power plants in China. The frequent overloading is 0% to 30% ot the designed capacity. To achieve the stable performance of CFBs in practice, an appropriately designed MSW storage capacity is suggested to build in a plant to buffer and reduce the frequency of the load changes.

流体悬浮床配合细节护理对严重烧伤治疗患者外观及功能恢复的影响

目的:探讨流体悬浮床配合细节护理对严重烧伤患者创面外观及身体功能恢复的影响。方法:回顾性分析2018年1月-2022年1月进行治疗的98例严重烧伤患者临床资料,根据其护理方式与治疗床的不同分为两组,对照组(n=50,常规护理+传统翻身床),观察组(n=48,细节护理+流体悬浮床)。比较两组患者创面恢复相关指标、创面外观、功能恢复、创伤后成长水平及并发症。结果:干预后,观察组创面愈合时间、抗生素使用时间短于对照组(P<0.05),体温低于对照组(P<0.05);干预后6个月,观察组创面外观优良率高于对照组(P<0.05),观察组健康调查简表(36-item short form,SF-36)各维度评分均高于对照组(P<0.05),观察组创伤后成长评定量表(Chinese-posttraumatic growth inventory,C-PTGI)各维度评分均高于对照组(P<0.05);住院期间,观察组总并发症发生率低于对照组(P<0.05)。结论:流体悬浮床配合细节护理可以促进严重烧伤患者早日康复,且能改善患者创面外观,促进患者功能恢复,提高患者创伤后成长水平。

医疗废物流化床焚烧过程中多孔氧化铝床料抑制PAHs生成的机理

焚烧是医疗废物处置的主要方法,但在医疗废物焚烧过程中会产生大量的持久性剧毒有机污染物如多环芳烃(PAHs)、二噁英等。提出利用多孔氧化铝替代传统石英砂作为流化床焚烧炉床料,研究了流化床不同运行工况下多孔氧化铝对医疗废物焚烧过程中PAHs生成的影响规律,获得了多孔氧化铝床料抑制医疗废物焚烧过程中PAHs生成的最优工艺参数,并从传热、催化和吸附角度揭示了多孔氧化铝抑制医疗废物焚烧过程中PAHs生成的机理。结果表明:采用多孔氧化铝床料替代传统石英砂床料后,医疗废物焚烧烟气中PAHs浓度和其毒性当量浓度均可以降低50%以上;多孔氧化铝床料主要通过传热、催化和吸附作用降低了烟气中PAHs前驱物的浓度,削减了PAHs的生成;当焚烧温度为800℃、过剩空气系数为1.50时,多孔氧化铝床料抑制烟气中PAHs生成的效果最佳。

城市垃圾焚烧发电技术及运用分析

基于城市垃圾利用率不足、垃圾焚烧发电技术落后问题,选取西安某垃圾焚烧发电厂作为研究对象,分析燃烧发电技术的运用思路,通过做好热解炉、炉排、流化床焚烧,采取垃圾储存、烟气处理与渗滤液处理技术方案,使焚烧发电的效果达到预期。研究结果表明,焚烧发电技术的应用价值较高,不仅能实现对城市垃圾的环保化、无害化处理,而且有利于清洁发电技术推广,对落实节能减排发展理念具有借鉴价值。

热处置CFB焚烧飞灰作混合材对水泥性能的影响

在使用循环流化床(CFB)焚烧技术处置城市生活垃圾过程中,会产生大量垃圾焚烧飞灰(简称CFB灰),它是Cu、Zn、Cr、Pb等重金属离子浸出和二噁英含量超标的危险固废,不经安全处置不能直接填埋或资源化利用。故此,本文研究了热处置对CFB灰用作水泥混合材的改性效果,结果表明:CFB灰直接用作水泥混合材的火山灰活性很低,仅为21.68%;所含少量Al单质的反应会导致水泥浆体膨胀,氯盐和二噁英含量高不符合作为水泥混合材要求;经1200℃,60min热改性后,火山灰活性提高至65.89%,氯离子和二噁英含量降低至1.08%和0.98ng TEQ/kg,当掺量不大于10%时满足制备P·O42.5水泥要求。

流化床反应器结构优化

简单说明了流化床反应器的发展,并对流化床反应器的主要结构以及流化床反应器的分类进行了分析。在此基础上,以某规格为2 400 mm×10 000 mm的流化床反应器为例,对该流化床反应器的原有结构缺陷以及使用中存在的问题进行了解析与探索,并以此为切入点提出了一套流化床反应器结构的优化与改进方案。结果表明,流化床反应器结构优化后,原有缺陷问题得到有效解决,流化床反应器使用年限得以延长。

循环流化床垃圾焚烧炉CO排放控制优化措施及实例应用

本文以某垃圾焚烧厂CO排放改造工程为例,介绍了循环流化床垃圾焚烧炉一氧化碳排放的主要影响因素与排放优化措施,为采用循环流化床工艺的垃圾焚烧厂的达标排放提供参考。

激光电离飞行时间质谱在线检测二[口恶]英系统在某生活垃圾焚烧厂的应用

利用激光电离飞行时间质谱在线检测二[口恶]英系统对某生活垃圾循环流化床焚烧炉烟气中二[口恶]英排放进行连续在线监测,通过调整焚烧工况,探究不同工况对二[口恶]英排放的影响。结果表明:活性炭用量从10 kg/h提升至30 kg/h,对二[口恶]英浓度降低效果并不显著,二[口恶]英稳态浓度仅下降13.33%;烟气中投用抑制剂,可使异常状况导致的高浓度二[口恶]英排放能更快地恢复至正常低浓度排放水平;减少入炉垃圾量,启用辅燃,二[口恶]英排放低且稳定,其毒性当量(TEQ)浓度均值为0.028 ng/m^(3)。稳定焚烧工况,使垃圾充分燃烧,从源头减少二[口恶]英生成,是控制二[口恶]英排放较有效的方法;二[口恶]英与14种锅炉运行参数之间的相关性较弱,其排放是一个综合性的问题,与诸多因素有关,不能用单一参数进行衡量。