日开发龙卷式垃圾焚烧炉

日本正在研究开发一项新的垃圾焚烧炉技术，它采用气化反应燃烧方式，能够抑制二恶英等有害物质的排放量。 这种新型锅炉叫做“龙卷炉”，垃圾气化后，在炉子的中央部分燃烧，仿佛是由火焰形成的龙卷风，火焰不接触炉体内侧，因此不需要耐火材料，并且炉体分段建造，结构简单，便于搬运和安装。 目前长崎县境内的大学、企业及有关团体成立了“龙卷炉”研究会，并且已经制作出试验炉，这种试验炉每小时可焚烧湿度在50%以下的垃圾200公斤，点火时只需要少量的柴油，以水作为助燃剂，燃烧温度可达1200至1300报氏度。 (张石)     

某“W”型锅炉炉效低的综合治理

针对某锅炉经济性差的问题,从设备、运行及自动控制等方面分析,并进行了相应整改。影响炉效的主要因素有煤质恶化、灰渣含碳量高、排烟温度高和CO浓度高等,同时炉膛燃烧不稳定也是影响燃烧效率的重要因素。通过漏风整改、制粉系统优化、燃烧优化调整和控制系统优化等方法有效提高了锅炉经济性。研究表明：分析锅炉经济性降低的影响因素时应抓住主要因素,兼顾其他,科学的生产管理是保证锅炉运行经济性的重要基础;入炉煤质恶化是最主要的外在因素;良好的自动控制系统能有效稳定燃烧参数,提高燃烧效率;降低飞灰含碳量的主要工作应集中在制粉系统优化调整;完整而系统的燃烧调整试验能够保证锅炉运行控制参数的科学合理,并需要正确调整氮氧化物排放和锅炉效率之间的关系。     

“W”火焰超临界锅炉煤质变化时的燃烧调整研究

介绍了2×650 MW超临界机组“W”火焰锅炉燃烧系统组成及特性,指出影响煤粉炉燃烧的主要因素有炉膛温度、煤粉的浓度和细度、燃煤挥发分及燃煤发热量等.分析了燃用煤质偏离设计值时,“W”火焰超临界锅炉燃烧状况,并给出了调整方案.     

一项降低电厂Nox排放量的技术

对某厂现有锅炉的燃烧调整试验表明，针对不同的锅炉和煤种，通过调整锅炉运行的过剩空气系数或改变二次风配风方式，可达到降低NOx排放量的目的。     

钢铁企业发展垃圾发电大有可为

重庆钢铁集团公司充分发挥自身优势,转变观念,开拓创新,引进世界一流技术,掌握垃圾焚烧发电技术,建成全国最大的垃圾焚烧炉制造基地,取得良好的经济效益和社会效益,为发展循环经济,建立资源节约型和环境友好型的生态文明社会作出积极贡献。     

论YG-75/5.29-M18型循环流化床锅炉燃用煤泥的燃烧调整

介绍了循环流化床锅炉燃用煤泥的燃烧调整方法，阐述了燃用煤泥技术对电厂降低成本，提高经济效益及社会效益的积极意义。     

垃圾焚烧炉配套袋式除尘器的设计

详述了某垃圾焚烧炉配套袋式除尘器的设计实例，介绍了该场合下袋式除尘器及其配套设备的设计原则及注意事项。按此思路设计的5套袋式除尘器已投入运行。应用效果较好。     

信息与动态

矿渣成为生产沉淀型CaCO3的新来源Chemical Engineering,2010,118(1):14美国CarbonX股份有限公司开发了一项工艺,可用CO2及工业固体废弃物生产具有很好销售市场的矿物产品。通过该工艺,可以炼钢厂炉渣或燃煤电厂、水泥窑炉及市政垃圾焚烧炉产生的粉煤灰为     

电厂燃煤过程中汞控制技术研究

燃煤电厂汞控制技术分燃烧前、燃烧中和燃烧后脱汞,燃烧后脱汞技术为主要汞控制排放工艺,其中吸附剂吸附方法的研究较为广泛。基于国内外近几年燃煤电厂烟气脱汞技术的研究,综述了汞控制技术的最新进展。     

火电厂降低NOx排放的技术研究

NOx是燃煤电厂烟气排放三大有害物（SO2、NOx及悬浮颗粒物TSP）之一。从污染角度考虑的氮氧化物主要是NO和NO2,统称为NOx。介绍了NOx的生成机理,即热力型NOx和燃料型NOx,前者由参与燃烧的空气中所含的N2生成,后者由燃料本身的氮元素生成。分析了低氮燃烧技术、SCR烟气脱硝技术、SNCR烟气脱硝技术及SCR＋SNCR组合式等NOx控制技术。其中,在燃烧过程中降低NOx生成的主要手段是采用分级燃烧,降低燃烧区域的氧浓度和降低火焰温度;在燃烧后可采用烟气处理技术降低烟气中的NOx含量。     

Oxidation catalyst of iron oxide suppressing dioxin formation in polyethylene combustion

A new iron oxide catalyst, which has a superior oxidation activity in carbon monoxide and polyethylene (PE) combustion, was synthesized by an aqueous solution reaction. Catalytic oxidation of carbon monoxide over six kinds of hematite obtained from the goethite was done using a microcatalytic pulse reactor, and the composition of the hematite with the highest oxidation activity was determined. With the aim of suppressing dioxin formation on combustion, incineration tests of solid wastes in PE refuse bags with and without the goethite were carried out using a commercial semibatch-type incinerator with a combustion chamber of 6.2 m³. The result confirmed that the concentration of dioxins in the flue gas decreased considerably when the refuse was incinerated in PE bags manufactured with goethite. Received: July 24, 2000 / Accepted: October 18, 2000     

Numerical simulation of municipal solid waste combustion in a novel two-stage reciprocating incinerator

A mathematical model was presented in this paper for the combustion of municipal solid waste in a novel two-stage reciprocating grate furnace. Numerical simulations were performed to predict the temperature, the flow and the species distributions in the furnace, with practical operational conditions taken into account. The calculated results agree well with the test data, and the burning behavior of municipal solid waste in the novel two-stage reciprocating incinerator can be demonstrated well. The thickness of waste bed, the initial moisture content, the excessive air coefficient and the secondary air are the major factors that influence the combustion process. If the initial moisture content of waste is high, both the heat value of waste and the temperature inside incinerator are low, and less oxygen is necessary for combustion. The air supply rate and the primary air distribution along the grate should be adjusted according to the initial moisture content of the waste. A reasonable bed thickness and an adequate excessive air coefficient can keep a higher temperature, promote the burnout of combustibles, and consequently reduce the emission of dioxin pollutants. When the total air supply is constant, reducing primary air and introducing secondary air properly can enhance turbulence and mixing, prolong the residence time of flue gas, and promote the complete combustion of combustibles. This study provides an important reference for optimizing the design and operation of municipal solid wastes furnace.     

Synthetic aggregates from combustion ashes using an innovative rotary kiln

This paper describes the use of a number of different combustion ashes to manufacture synthetic aggregates using an innovative rotary 'Trefoil' kiln. Three types of combustion ash were used, namely: incinerated sewage sludge ash (ISSA); municipal solid waste incinerator bottom ash (MSWIBA-- referred to here as BA); and pulverised fuel ash (Pfa). The fine waste ash fractions listed above were combined with a binder to create a plastic mix that was capable of being formed into 'green pellets'. These pellets were then fired in a Trefoil kiln to sinter the ashes into hard fused aggregates that were then tested for use as a replacement for the natural coarse aggregate in concrete. Results up to 28 days showed that these synthetic aggregates were capable of producing concretes with compressive strengths ranging from 33 to 51 MPa, equivalent to between 73 and 112% of that of the control concrete made with natural aggregates.     

Influence of bromine on metal volatilization in waste combustion

Co-combustion tests of municipal solid waste and bromine-containing waste plastics have been performed in the TAMARA test incinerator in order to investigate the fate of bromine in waste combustion. HBr is the main bromine combustion product. Approximately 50% of the bromine inventory stays in the grate ashes, which is much more than is found for chlorine. The percentage of bromine transferred into the fly ash also exceeds that of chlorine. There is a strong indication that bromine has a promoting effect upon the volatility of most of the heavy metals that are typically mobilized by chlorine. Received: February 2, 2000 / Accepted: March 3, 2000     

Correlations between homologue concentrations of PCDD/Fs and toxic equivalency values in laboratory-, package boiler-, and field-scale incinerators

The toxic equivalency (TEQ) values of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are predicted with a model based on the homologue concentrations measured from a laboratory-scale reactor (124 data points), a package boiler (61 data points), and operating municipal waste incinerators (114 data points). Regardless of the three scales and types of equipment, the different temperature profiles, sampling emissions and/or solids (fly ash), and the various chemical and physical properties of the fuels, all the PCDF plots showed highly linear correlations (R(2)>0.99). The fitting lines of the reactor and the boiler data were almost linear with slope of unity, whereas the slope of the municipal waste incinerator data was 0.86, which is caused by higher predicted values for samples with high measured TEQ. The strong correlation also implies that each of the 10 toxic PCDF congeners has a constant concentration relative to its respective total homologue concentration despite a wide range of facility types and combustion conditions. The PCDD plots showed significant scatter and poor linearity, which implies that the relative concentration of PCDD TEQ congeners is more sensitive to variations in reaction conditions than that of the PCDF congeners.     

Copper leaching of MSWI bottom ash co-disposed with refuse: Effect of short-term accelerated weathering

Co-disposal of refuse with municipal solid waste incinerator (MSWI) bottom ash (IBA) either multi-layered as landfill cover or mixed with refuse could pose additional risk to the environment because of enhanced leaching of heavy metals, especially Cu. This study applied short-term accelerated weathering to IBA, and monitored the mineralogical and chemical properties of IBA during the weathering process. Cu extractability of the weathered IBA was then evaluated using standard leaching protocols (i.e. SPLP and TCLP) and co-disposal leaching procedure. The results showed that weathering had little or no beneficial effect on Cu leaching in SPLP and TCLP, which can be explained by the adsorption and complexation of Cu with DOM. However, the Cu leaching of weathered IBA was reduced significantly when situated in fresh simulated landfill leachate. This was attributed to weakening Cu complexation with fulvic acid or hydrophilic fractions and/or intensifying Cu absorption to neoformed hydr(oxide) minerals in weathered IBA. The amount of total leaching Cu and Cu in free or labile complex fraction (the fraction with the highest mobility and bio-toxicity) of the 408-h weathered IBA were remarkably decreased by 86.3% and 97.6% in the 15-day co-disposal leaching test. Accelerated weathering of IBA may be an effective pretreatment method to decrease Cu leaching prior to its co-disposal with refuse.     

Combustion characteristics of Malaysian municipal solid waste and predictions of air flow in a rotary kiln incinerator

Malaysia is in dire need of alternatives to landfilling for solid waste management. Recently, landfills have faced the problems of overfilling, overflowing of leachates leading to pollution of water resources, and uncontrolled dust emissions adversely affecting the local environment. With the rising cost of urbanization coupled with the high rate of waste generation, one possible method of waste treatment that is receiving particular attention by the government is incineration. Incineration of solid waste is rather new in Malaysia, with limited usage in handling small sources of waste generation such as the municipal solid waste (MSW) of resort islands; however, its potential in ameliorating the problems associated with solid waste treatment may make it an attractive alternative to landfill. This article presents the results of test runs conducted to investigate the performance of a locally designed and manufactured rotary kiln incinerator (RKI). The test runs were conducted using MSW collected from the Shah Alam municipality. The combustion efficiency was analyzed by looking at the temperature profiles and chemical species concentrations. To complement the combustion characteristics measurements, predictions of the air flow in the incinerator during the process were also investigated. The overall performance of the RKI suggests that it is suitable for treating MSW.     

On-line detection of metal pollutant spikes in MSW incinerator flue gases prior to clean-up

SUWIC's unique mobile metals emissions monitoring laboratory has been used to measure metal pollutant spikes in the flue gas from a municipal solid waste incinerator, prior to gas clean-up. The laboratory has a heated sampling probe that extends into the plant, allowing the simultaneous on-line measurement of the concentrations of more than 30 metals by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). As little is known about temporal variation in metal concentrations, this capability is seen as a major advance. The graphs of continuous measurements show that the elemental loading is far from uniform, and that concentrations fluctuate far more than may have been conventionally expected. There are occasional significant spikes in the emission profiles for cadmium and mercury, which are believed to be due to specific items in the waste feed material. Continuous monitoring measurements are of significant value for those seeking to model metal behaviour in combustion and in pollution control devices.     

Flow analysis of metals in a municipal solid waste management system

This study aimed to identify the metal flow in a municipal solid waste (MSW) management system. Outputs of a resource recovery facility, refuse derived fuel (RDF) production facility, carbonization facility, plastics liquefaction facility, composting facility, and bio-gasification facility were analyzed for metal content and leaching concentration. In terms of metal content, bulky and incombustible waste had the highest values. Char from a carbonization facility, which treats household waste, had a higher metal content than MSW incinerator bottom ash. A leaching test revealed that Cd and Pb in char and Pb in RDF production residue exceeded the Japanese regulatory criteria for landfilling, so special attention should be paid to final disposal of these substances. By multiplying metal content and the generation rate of outputs, the metal content of input waste to each facility was estimated. For most metals except Cr, the total contribution ratio of paper/textile/plastics, bulky waste, and incombustible waste was over 80%. Approximately 30% of Cr originated from plastic packaging. Finally, several MSW management scenarios showed that most metals are transferred to landfills and the leaching potential of metals to the environment is quite small.     

Effect of leachate recirculation on the migration of copper and zinc in municipal solid waste and municipal solid waste incineration bottom ash co-disposed landfill

Municipal solid waste incinerator (MSWI) bottom ash was allowed to be disposed of with municipal solid waste (MSW) in landfill sites in the recently enacted standard of China. In this study, three sets of simulated landfill reactors, namely, conventional MSW landfill (CL), conventional MSWI bottom ash and MSW co-disposed landfill (CCL), and leachate recirculated MSWI bottom ash and MSW co-disposed landfill (RCL), were operated to investigate the environmental impact of the co-disposal. The effect of leachate recirculation on the migration of Cu and Zn in the co-disposed landfill was also presented. The results showed that the co-disposal of MSWI bottom ash with MSW would not enhance the leaching of Cu and Zn from landfill. However, the co-disposal increased the Cu and Zn contents of the refuse in the bottom layer of the landfill from 56.7 to 65.3 mg/kg and from 210 to 236 mg/kg, respectively. The recirculation of the leachate could further increase the Cu and Zn contents of the refuse in the bottom layer of the landfill to 72.9 and 441 mg/kg, respectively. Besides these observations, the results also showed that the co-disposed landfill with leachate recirculation could facilitate the stabilization of the landfill.