垃圾焚烧电厂烟气降温模拟分析

采用fluent软件对江苏某垃圾焚烧厂的烟气2级喷水减温流程分别进行了模拟,并根据模拟结果分析了反应塔和冷却塔内烟气的温度、流速、湿度等在塔内的径向分布情况.结果表明,冷却塔和反应塔在不同进口烟气温度下将烟气温度降低到各自相应同一值时所需喷水量的模拟值和实际值均具有较好的一致性,模拟结果具有一定的可靠性;冷却塔内烟气温...     

Polychlorinated dibenzo-p-dioxins, dibenzofurans and 'dioxin-like' PCBs in flue gas emissions from municipal waste management plants

The aim of this work is to give representative data on polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyl (PCBs) from stack gas emissions of an urban solid waste management plant which has to comply with the limit of 0.1 ng I-TEQ/Nm3. In particular, the study is focused on 29 target compounds, the seventeen 2,3,7,8-PCDDs/Fs, four non-ortho PCBs and eight mono-ortho PCBs which configure so-called 'dioxin-like' PCBs (DL-PCBs). To this end, emission measurements were performed during one year over the three operating combustion lines in a selected waste management plant. In general, accurate methodology allowed characterizing all target compounds in almost all the samples analyzed. In addition, a typical pattern for DL-PCBs is reported. The pattern presented PCB #118 to be the highest, nevertheless the figures demonstrated DL-PCBs contribution to the total TEQ around 3% being PCB #126 the most important congener due to its TEF of 0.1. Finally, remarkable differences were achieved in comparison with both environmental and biological samples such as soils, sediments, human milk or fish since these matrices may present DL-PCB contribution to the total TEQ up to 77%.     

垃圾焚烧飞灰的资源化处置前景

对大量数据进行统计分析,得出垃圾焚烧飞灰中主要重金属元素和二噁英类物质的含量分布特征,并根据垃圾焚烧飞灰的综合特点,结合其他领域现有技术,初步提出了3个垃圾焚烧飞灰的资源化处置方案:①烧制陶粒;②作为凝石成岩剂的原料;③作为上流式厌氧污泥床(UASB)或膨胀式颗粒污泥床(EGSB)废水处理装置的生化反应促进剂.同时回收重金属,并对其前景进行了初步分析.若将上述3个方案逐步完善,不但能节约1000～2000元/t的垃圾焚烧飞灰处置费用,还能够产生很大的附加经济效益.     

A sulfur-resistant CuS-modified active coke for mercury removal from municipal solid waste incineration flue gas

Environmental Science and Pollution Research - Adsorption is a typical method for air pollutant removal from flue gas. A CuS-modified active coke (CuS/AC) sorbent was developed to improve the...     

医疗废弃物焚烧挥发性氯含量与热值测试与估算

通过测定上海某医疗废弃物处置公司设定燃烧工况条件下某时间段内烟气中HC l的平均排放速率,估算出上海地区医疗垃圾废物中的可燃烧转化氯含量在2.33%~2.64%左右;通过测定各较小采样时间段(2 m in)的烟气HC l浓度测定发现批次进料造成烟气中HC l浓度近4倍的波动,通过初步的热平衡估算得到医疗废弃物的热值大致在21.8 M J/kg,得到的结果可为我国医疗废弃物的焚烧工艺设计提供基础依据。     

Characterization of municipal solid waste incineration and flue gas emission under anoxic environment in Tibet Plateau

Environmental Science and Pollution Research - Waste incineration is a process of full combustion reaction between waste and oxygen at high temperature. It is a new problem whether the special...     

Mercury removal from incineration flue gas by organic and inorganic adsorbents

Experiments were performed to investigate various adsorbents for their mercury removal capabilities from incineration flue gases. Four different materials were tested; Zeolite, Bentonite, activated carbon (AC), and wood char. Real incineration off-gas and in-lab simulated combustion flue gases (N2 + Hg) were used. Three cylindrical-shaped sorbent columns with 5 cm in diameter and 20 cm in length were used. The gas flow rate was fixed at 660 l/h at all times. Concentrations of NO, CO, O2, CO2, SO2, H2O, HCl, and mercury were continuously monitored. Mercury removal efficiencies of natural Zeolite and Bentonite were found to be much lower than those of the referenced AC. Amount of Hg removed were 9.2 and 7.4 microg/g of Zeolite and Bentonite, respectively. Removal efficiencies of each layer consisted of inorganic adsorbents were no higher than 7%. No significant improvement was observed with sulfur impregnation onto the inorganic adsorbents. Organic adsorbents (wood char and AC) showed much higher mercury removal efficiencies than those of inorganic ones (Zeolite and Bentonite). Mercury removal efficiency of wood char reached over 95% in the first layer, showing almost same effectiveness as AC which currently may be the most effective adsorbents for mercury. Amount of mercury captured by wood char was approximately 0.6 mg/g of wood char, close to the amount captured by AC tested in this study. Hence, wood char, made from the waste woods through a gasification process, should be considered as a possible alternative to relatively expensive AC.     

医疗垃圾焚烧飞灰重金属形态分析

利用原子吸收光谱仪分别对医疗垃圾焚烧飞灰重金属含量和重金属形态及其随颗粒度分布特性进行了分析,结果表明,飞灰中Cd、Zn、Pb等的浸出浓度远超标与这些重金属的可交换态和碳酸盐态含量较高有关;飞灰颗粒度主要在96 μm以下,96～150 μm的颗粒中Cd、Pb含量最高,且Zn、Cd的形态以可交换态为主.     

Dehalogenation potential of municipal waste incineration fly ash

BACKGROUND, AIMS AND SCOPE: It is well known that the fly ash from filters of municipal waste incinerators (MWI-FA) shows dehalogenation properties after heating it to 240-450 degrees C. However, this property is not general, and fly ash samples do not possess dehalogenation ability at all in many cases. Fly ash has a very variable composition, and the state of the fly ash matter therefore plays the decisive role. In the present paper, the function of important components responsible for the dehalogenation activity of MWI-FA is analysed and compared with the model fly ash. METHODS: With the aim of accounting for the dehalogenation activity of MWI-FA, the following studies of hexachlorobenzene (HCB) dechlorination were performed: The role of copper in dehalogenation experiments was evaluated for five types of metallic copper. The gasification of carbon in MWI-FA was studied in the 250-350 degrees C temperature range. Five different kinds of carbon were used, combined with conventional Cu(o) and activated nanosize copper powder. The dechlorination experiments were also carried out with Cu(II) compounds such as CuO, Cu(OH)2, CuCl2 and CuSO4. The results were discussed from the standpoint of thermodynamics of potential reactions. Based on these results, the model of fly ash was proposed, containing silica gel, metallic copper and carbon. The dechlorination ability of MWI-FA and the model fly ash are compared under oxygen-deficient atmosphere. CONCLUSIONS: The results show that, under given experimental conditions, copper acts in the dechlorination as a stoichiometric agent rather than as a catalyst. The increased surface activity of copper enhances its dechlorination activity. It was found further that the presence of copper leads to a decrease in the temperature of carbon gasification. The cyclic valence change from Cu(o) to Cu+ or Cu2+ is a prerequisite for the dehalogenation to take place. RECOMMENDATION AND OUTLOOK: Thermodynamic analysis of the dechlorination effect, as well as the comparison of dechlorination pathways on MWI-FA and model fly ash, can provide a deeper understanding of the studied reaction.     

氧化镁烟气脱硫废渣-硫酸镁废水-高钙粉煤灰脱氮除磷

在分析高钙粉煤灰（HCFA）对模拟废水脱氮除磷特性的基础上,先后采用氧化镁烟气脱硫废渣（MFGDR）、烟气脱硫（硫酸镁）废水和HCFA综合处理酸洗磷化废水和垃圾渗滤液。当酸洗磷化废水和垃圾渗滤液混合废水的NH3-N浓度为1 135 mg·L-1、PO43--P浓度为2 766 mg·L-1时,通过调整氮磷比,经过吸附、化学沉淀反应等,将污染物吸附、转化为磷酸铵镁等,并进行固液分离,NH3-N和PO43-P的去除率分别可达到98%和99%,废水经处理可达到排放标准。不仅同步解决了热电固废、硫酸镁废水、酸洗磷化废水以及垃圾渗滤液的处理处置问题,还以废治废,降低了药剂成本,具有良好的应用前景。     

Polycyclic aromatic hydrocarbons in weathered bottom ash from incineration of municipal solid waste

Polycyclic aromatic hydrocarbons (PAHs) were analysed in weathered bottom ash from different municipal solid waste incinerators. The sum of the 16 "USEPA" PAHs was found to vary from 480 to 3590 microg/kg. The amounts of carcinogenic PAHs were between 89 and 438 microg/kg ash. The maximum levels of carcinogenic PAHs exceed the Swedish generic guidelines for sensitive land use. The results showed that the amount of PAHs in fresh and weathered bottom ash are similar, indicating that the PAHs are strongly bound to the ash and only limited amounts are released to the surroundings.     

The utilization of catalyst sorbent in scrubbing acid gases from incineration flue gas

Catalyst sorbents based on alumina-supported CuO, CeO2, and CuO-CeO2 were applied to a dry scrubber to clean up the SO2/HCl/NO simultaneously from pilot-scale fluidized-bed incineration flue gas. In the presence of organic compounds, CO and the submicron particles SO2 and HCI removed by the fresh catalyst sorbents and NO reduced to N2 by NH3 under the catalysis of fresh and spent desulfurization/dechloridization (DeSO2/DeHCl) catalyst sorbents (copper compounds, Cu, CuO, and CuSO4) were evaluated in this paper. The fresh and spent catalyst sorbents were characterized by the Brunner-Emmett-Teller method (BET), X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), inductively coupled plasma-mass spectrometry (ICP-MS), and the elemental analyzer (EA). The study showed that the performances of CuO, CeO2, and CuO-CeO2/gamma-Al2O3 were better than that of Ca(OH)2. The removal efficiency of SO2 and HCl was 80-95% in the dry scrubber system. Under NH3/NO = 1, NO could not be reduced to N2 because it was difficult to control the ratio of air/fuel in the flue gas. For estimating the feasibility of regenerating the spent catalyst sorbents, BET and EA analyses were used. They indicated that the pore structures were nearly maintained and a small amount of carbon accumulated on their surface.     

危险废物焚烧飞灰中重金属的稳定化处理

以上海市某危险废物焚烧厂飞灰为研究对象,采用Na2S、FeSO4、Na3PO4、和Na3C3N3S34种不同类型化学稳定药剂对飞灰进行了稳定化处理,并应用XRD、IR、SEM和连续化学提取法等仪器和手段对Na3C3N3S3处理焚烧飞灰的产物进行分析研究。研究结果表明,Na3C3N3S3对飞灰中的重金属Cr、Pb、Zn的稳定效果最好,Na3PO4对Cr无明显稳定效果。稳定后产物表面变得致密化,Na3C3N3S3与重金属离子生成的沉淀物干燥后无明显晶型存在。经稳定处理后飞灰中的重金属形态由弱酸提取态转化为可氧化态,减少了飞灰中重金属的浸出毒性。     

半干法烧结烟气脱硫灰的氧化改性

半干法烧结烟气脱硫灰中含有大量CaSO3,而CaSO3对于脱硫灰的稳定性具有重要影响,限制了脱硫灰的处理和综合利用。为了解决该问题,采用低温静态氧化改性实验和高温动态焙烧改性实验,在掺加和不掺加催化剂条件下,对含CaSO3的脱硫灰进行了氧化改性研究,并结合热重实验考察了半干法烧结烟气脱硫灰中CaSO3的高温动态氧化改性效果。结果表明,在低温为45、75和90℃时,掺入不同催化剂对半干法烧结烟气脱硫灰中CaSO3进行氧化改性2 h,效果依次为:MnO2 > Fe2O3 > 不掺催化剂 > V2O5,且CaSO3的氧化率均低于2.2%;在不掺催化剂的条件下,在350℃以上焙烧30~60 min,CaSO3的氧化率均可达到85%以上。结合热重分析结果发现,选择合适的焙烧温度和时间对提高CaSO3的氧化率有重要作用。     

城市生活垃圾焚烧飞灰的熔融分离处理

焚烧法处理城市生活垃圾已在世界先进发达国家广泛采用。垃圾焚烧飞灰含有大量的重金属,必须进行合理安全处置。在分析城市生活垃圾焚烧飞灰的物理化学性质基础上,研究了垃圾焚烧飞灰固化成型、熔融分离的无害化处理新工艺。实验结果表明：飞灰固化成球的适宜粘结剂为5%～7%消石灰,养护时间为10～12 d,固化球强度达0.24 kg/cm²以上,可以满足运输和熔化分离要求;固化后的飞灰在1 300℃左右熔融分离后,重金属的分离效果好,达到97%以上,可达到无害化处理标准;对1 300℃和1 400℃熔融分离后熔渣的重金属浸出毒性测试显示,重金属浸出毒性问题可以完全解除。研究结果表明,采用飞灰固化-熔融分离工艺处理城市生活垃圾焚烧飞灰是可行的。     

污水厂出水回用于污泥焚烧烟气的净化

开展了污水处理厂出水回用于污泥焚烧烟气净化的实验研究。生化出水净化吸收污泥焚烧烟气的效果与气水比、进气浓度、进水pH、进水碱度和水温等因素有关。研究结果表明,气水比10∶1,进水pH为7条件下,生化出水能够有效吸收污泥焚烧烟气中的各种污染物质,出气中气体污染物低于《生活垃圾焚烧污染控制标准》（GB18485-2001）的排放限值要求,吸收后出水各指标均低于《污水综合排放标准》（GB8978-1996）中污染物排放限值的要求。该工艺脱硫效率可达90%,具有系统简单可靠、以废治废、不产生二次污染等优点。     

Chlorobenzenes removal from municipal solid waste incineration fly ash by surfactant-assisted column flotation

The organic contaminants in municipal solid waste incineration (MSWI) fly ash, including chlorinated aromatic compounds and polycyclic aromatic hydrocarbons, have high toxicity and a potential negative impact on the environment. An effective and low energy consumption technique to remove the organic contaminants from MSWI fly ash is required urgently. Organic contaminants, such as chlorobenzenes (CBzs), in MSWI fly ash are known to become enriched in the unburnt carbon (UC) fraction. It is proposed that removal of UC from fly ash will result in the effective removal of most organic micropollutants. In this research, we use a technique of surfactant-assisted column flotation to decontaminate MSWI fly ash by removal of the CBzs-enriched UC from MSWI fly ash. We find that 39.8% of CBzs can be removed from fresh MSWI fly ash with 61.7% UC removal efficiency, whereas only 33.2% of CBzs can be removed from weathered MSWI fly ash with a low UC removal efficiency of 33.7%. By adding a mixture of two kinds of surfactants: sorbitan mono-oleate and polyoxyethylene (20) sorbitan mono-oleate to the weathered fly ash, 47.0% of CBzs were removed at the hydrophile lipophile balance value of 13.5, while the UC removal efficiency increased to 49.0%. The results show that surfactants can enhance CBzs and UC removal efficiencies during the column flotation process. Higher CBzs and UC removal efficiencies can be expected by further optimizing the conditions of surfactant-assisted column flotation.     

The preparation of slow-release fertilizers with biomass ash and water/waste acid solutions from desulfurization and denitrification of flue gas

Environmental Science and Pollution Research - In this study, a method of preparing fertilizers with the fly ash from biomass power plants and the waste acid solution from flue gas desulfurization...     

CaCO3类吸收剂净化焚烧烟气中HCl气体的研究

通常烟气中的酸性气体采用Ca(OH)2净化,然而当烟气温度在300 ℃以上时,Ca(OH)2喷入到烟气中将快速生成CaCO3.研究了两种CaCO3的反应特性,比较了200～900 ℃内CaCO3类吸收剂和Ca(OH)2与烟气中HCl气体的反应率,发现在600 ℃左右和800 ℃及以上,CaCO3类吸收剂的反应率与Ca(OH)2相当或更高;CaCO3类吸收剂、特别是改性CaCO3可替代Ca(OH)2作为干式净化HCl气体的吸收剂,合适的反应温度在600 ℃左右.     

CaCO3类吸收剂净化焚烧烟气中HCI气体的研究

通常烟气中的酸性气体采用Ca（OH）2净化，然而当烟气温度在300℃以上时，Ca（OH）2喷入到烟气中将快速生成CaCO3。研究了两种CaCO3的反应特性，比较了200-900℃内CaCO3类吸收剂和Ca（OH）2与烟气中HCl气体的反应率，发现在600℃左右和800℃及以上，CaCO3类吸收剂的反应率与Ca（OH）2相当或更高；CaCO3类吸收剂、特别是改性CaCO3可替代Ca（OH）2作为干式净化HCl气体的吸收剂，合适的反应温度在600℃左右。