Application of the ISCST3 model for predicting PCDD/F concentrations in agricultural soil in the vicinity of a MSWI plant in China

Based on the Industrial Source Complex Short-Term Version 3 (ISCST3) model, a simplified modeling approach was developed to predict concentrations of congeners of polychlorinated-p-dioxins and dibenzofurans (PCDD/Fs) of agricultural soil, within a radius of 3 km from a municipal solid waste incinerator (MSWI) plant after its 4-year operation in Hangzhou, China. Comparisons were made between the measured and estimated congener-specific concentrations and the international-toxic equivalent (I-TEQ) values of soil samples with respect to distance from the stack. The results indicate that the predictions of soil PCDD/F concentrations and I-TEQ values were generally lower than their observations, and that the higher the degree of under-estimation seems, the greater the further downwind one gets. Nevertheless, most of the predictions were in good agreement with the trend of measured ones and were within a factor of ten for samples located within 1 km of the plant. Besides, analysis of contributions of various deposition pathways confirms that in addition to wet particle deposition, the dry gaseous deposition is essential for realistic prediction of PCDD/F depositions to soil, especially for tetra-and penta-chlorinated dioxins.

Development of non-premixed porous inserted regenerative thermal oxidizer

In this study, a porous inserted regenerative thermal oxidizer (PRTO) system was developed for a 125 kW industrial copper-melting furnace, due to its advantages of low NO x emissions and high radiant efficiency. Zirconium dioxide (ZrO2 ) ceramic foams were placed into the combustion zone of a regenerative thermal oxidizer (RTO). Different performance characteristics of the RTO and PRTO systems, including pressure drop, temperature distribution, emissions, and energy efficiency, were evaluated to study the effects of the porous inserts on non-premixed CH4 combustion. It was found that the PRTO system achieved a significant reduction in the NOx emission level and a fuel saving of approximately 30% compared to the RTO system. It is most suitable for a lean combustion process at an equivalence ratio <0.4 with NOx and CO emission levels within 0.002%-0.003% and 0.001%-0.002%, respectively.

Naphthalene decomposition in a DC corona radical shower discharge

The naphthalene decomposition in a corona radical shower discharge (CRS) was investigated, with attention paid to the influences of voltage and initial naphthalene density. The OH emission spectra were investigated so as to know the naphthalene decomposing process. The by-products were analyzed and a decomposing theory in discharge was proposed. The results showed that higher voltage and relative humidity were effective on decomposition. The initial concentration affected the decomposing efficiency of naphthalene. When the initial naphthalene density was 17 mg/m3, the decomposition rate was found to be 70% under 14 kV. The main by-products were carbon dioxide and water. However, a small amount of carbonic oxide, 1,2-ethanediol and acetaldehyde were found due to the incomplete oxidization.

基于时间分辨粒子图像测速技术的水平轴风力机近尾迹特性的实验研究（英文）

目的：探索风力机运行在不同尖速比下近尾迹流场的瞬态和时均特性,揭示风力机近尾迹场的涡量、流速、湍流和雷诺应力演化规律,为相关的数值模拟提供实验对比数据支撑。创新点：将时间分辨粒子图像测速技术应用于风力机近尾迹测量可以捕捉到较高时间分辨率和高精度的流动信息,进而揭示风力机近尾迹详细的流动机理。方法：实验在风洞里面进行,利用时间分辨粒子图像测速技术获得风力机瞬时流场（图1-3）,通过调节风力机配套电机的负荷输出可以得到不同的运行尖速比。对测量得到的瞬时速度的后处理可以得到瞬时涡量以及湍动能和雷诺应力的时均值。结论：1.风力机近尾迹区域沿径向可分为速度增益区、速度保持区和速度亏损区,不同尖速比下速度恢复到主流速度的径向位置基本相同;2.在后半个半径长度区域内,径向平均速度沿径向方向有增加的趋势,而在叶尖以上,径向平均速度沿径向减小;3.近尾迹湍动能在径向方向上0.3倍和0.9倍半径高度处会出现峰值,而在0.6倍半径附近位置会出现湍动能最低值;4.在风力机近尾迹,雷诺剪切应力小于雷诺正应力,在叶根附近,轴向雷诺正应力大于径向雷诺正应力以及雷诺剪切应力,而在叶尖处,径向雷诺正应力大于轴向雷诺正应力以及雷诺剪切应力。

基于七个运行参数建立煤粉锅炉NO_x排放模型（英文）

目的:采用最小二乘支持向量机建立煤粉锅炉NO_x排放模型,即建立输入参数与NO_x之间的关系。合理选择输入参数不仅会降低模型的复杂度,而且会提高模型的精度。为此,本文探讨各输入参数对模型的影响,并最终保留合适数量的输入参数建立NO_x排放模型。创新点:1.采用最小二乘支持向量机建立NO_x排放模型;2.通过敏感性分析确定模型的最终输入参数。方法:1.根据专家知识及运行经验确定NO_x排放模型的初始输入参数(图2);2.根据锅炉的运行历史数据,采用最小二乘支持向量机建立NO_x排放模型;3.采用敏感性分析方法确定NO_x排放模型的最终输入参数(图11),并用其进行建模以验证模型的有效性。结论:1.采用最小二乘支持向量机建立的1000 MW超超临界前后墙对冲锅炉NO_x排放模型,可靠性和精度较高;2.经过敏感性分析,NO_x排放模型的输入参数由初始的33个降为7个,模型的复杂度降低且精度提高。