Effective incineration technology with a new-type rotary waste incinerator

The technology of steady combustion in a new type of rotary incinerator is firstly discussed. The formation and control of HCl,NOx and SO_(2) during the incineration of sampled municipal organic solid waste are studied with the incinerator. Results showed that the new model of rotary incinerator can effectively control and reduce the pollutant formations by post combustion.

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

Typical Refractories Design of Rotary Kiln Hazardous Waste Incineration System

This paper summarizes the current situation of China’s industrial hazardous waste treatment,the disposal technology and the characteristics of rotary kiln incineration system,analyzes the refractory lining design of rotary kiln incineration system in China,and puts forward optimization suggestions according to the process characteristics.

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.

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.

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.

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.

New Developments in Spinning Fluidised Bed Incineration Technology

At the present time, the sewage treatment plants in the UK produce about 25 million tons of sewage sludge each year at a concentration of 4% solids. New regulations forbid sea dumping and in the near future new incinerators will be required to dispose of about 5 million tons per year. Bubbling fluidised bed incinerators are widely used to burn sewage sludge at a typical consumption rate of about 0.02kg(dry)·s -1 ·m 2 , and it follows that over 300 conventional fluidised bed incinerators of 3m diameter could be required to cope with the increased demand.\;At Sheffield University Waste Incineration Centre (SUWIC) research work is being carried out to develop a novel spinning fluidised bed incinerator. The key factor to note is that when air flows up through a bed of near mono sized particles, it fluidises when the pressure drop across the bed is equal to the weight of the bed. Normally, the weight of the bed is determined by gravity. However, if the bed is contained by a cylindrical air distributor ‘plate’ that is rotating rapidly about its axis, then the effective weight of the bed can be increased dramatically. The airflow passing through the bed can be increased proportionally to the “g” level produced by the rotation and it follows that the process has been intensified. In exploratory tests with a spinning fluidised bed we have achieved combustion intensities with coal combustion as high as 100MW/m 3. A problem with burning coal is that it was difficult to remove the heat and rotating water seals had to be used to transfer cooling water into the bed. In the case of sewage and other sludges, this problem does not exist since the flue gases can remove the small amount of heat released. The rotating fluidised bed sludge incinerator is a novel device, which is very compact. It is able to solve the turndown problem encountered with conventional fluidised beds by simply changing the rotation speed. Bearing in mind that a centrifugal sludge de watering unit is already used on sludge incineration plants, it is likely that the rotating fluidised bed can be combined with the de watering unit, resulting in further process integration and intensification. Furthermore, our ash sintering system can be added to render the ash non toxic and unleachable thus reducing the cost of its disposal.

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.

Development and prospects of municipal solid waste (MSW) incineration in China

With the lack of space for new landfills,muni-cipal solid waste(MSW)incineration is playing an increasingly important role in municipal solid waste man-agement in China.The literatures on certain aspects of incineration plants in China are reviewed in this paper,including the development and status of the application of MSW incineration technologies,the treatment of leachate from stored MSW,air pollution control technologies,and the status of the fly-ash control method.Energy policy and its promotion of MSW-to-energy conversion are also elucidated.

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.

流化床污泥焚烧炉Pyrofluid~技术及应用

介绍了流化床污泥焚烧炉Pyrofluid系统的构成及特点，着重介绍了其能量回收和烟气处理系统的独特设计。全球应用实例证明，该工艺是一种简单、清洁和环保的污泥处理工艺。

危废综合焚烧回转窑经济高效运行的技术难点及对策

随着国内危险废物处理产业化快速发展,回转窑综合焚烧技术得到了广泛应用,但其工业化应用存在回转窑工况不稳定、焚烧性能差、灰渣率高等问题,严重影响焚烧效率和运行成本。以危废综合焚烧的灰渣率为切入点,从回转窑焚烧机理、工艺设计、工艺控制、工艺运行等方面分析了灰渣率高的原因,并提出了相应的解决对策和建议,为危废综合焚烧回转窑经济高效运行和产业高质量发展提供参考和借鉴。

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。

回转窑炉渣对刚玉-莫来石砖的侵蚀研究

对某公司危废焚烧回转窑燃烧带用后刚玉-莫来石砖进行取样,采用XRD、SEM结合EDS对残砖进行显微结构和成分分析,探索危废焚烧回转窑用刚玉-莫来石砖在含卤素及高含量钠盐炉渣侵蚀下的蚀损机制。结果表明:熔渣中的钠盐、钾盐及Br、Cl等元素侵蚀渗透能力强,在基质中产生的NaCl、KBr及方钠石等低熔点、低密度物质,一方面导致燃烧带的砖体高温性能降低,加快了物料对砖体的侵蚀磨损;另一方面导致砖体产生不可逆的体积膨胀,从而在回转窑运行过程中出现剥落。

Method for determining effective flame emissivity in a rotary kiln incinerator burning solid waste

Temperature is the most important parameter for the improvement of combustion efficiency and the control of pollutants.In order to obtain accurate flame temperatures in a rotary kiln incinerator using non-intrusive thermographic method,the effective flame emissivity was studied.A combined narrow-and wide-band model and Mie scattering method were used to calculate the radiative properties for gases and fly-ash particles under different combustion conditions.The effects of the air/waste ratio and fly-ash particles on the effective flame emissivity were discussed.The results of numerical calculations showed that the effective emissivity decreased from 0.90 to 0.80 when the air/waste ratio increased from 1.0 to 1.8,and the effect of the fly-ash particles was ignorable under the conditions discussed in this paper.Experimental measurement results indicated that the accuracy of the thermographic temperature measurements improved significantly if the setting of the flame emissivity was adjusted according to the air/waste ratio.

干化—焚烧工艺处理炼化企业固体废物工程实践

采用干化—焚烧工艺处理广东石化炼化一体化项目生产过程和污水处理过程中所产生的含油污泥和生化污泥,介绍了干化—焚烧装置的工艺流程、设计特点和运行情况。结果表明:干化—焚烧工艺能够实现大型炼化企业污泥及危险废物的减量化、无害化和稳定化;处理过程中产生的废水送至厂区内污水处理厂进行达标处理,所排放的烟气经脱硫、脱硝和除尘后,满足《危险废物焚烧污染控制标准》(GB 18484—2020)的要求,炉渣和飞灰送至满足环保资质要求的填埋场进行填埋。该装置的建设和运行对大型炼化一体化企业固体废物的处理处置具有借鉴意义。

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。