煤田火区碳排放量计算模型和关键参数研究

完善碳排放清单,是进行减排工作的基础,为了查明煤田火区对大气碳排放的贡献量,以煤氧复合作用学说为理论基础,从不同的研究思路出发,提出了烧失煤量法和排放通量法两种火区碳排放量计算模型。在明确模型中关键参数“释放因子”“排放系数α”“排放通量”“排放系数β”的具体含义的基础上,重点对各参数所对应的获取途径进行了研究论述：(1)释放因子通过在室内进行煤自燃模拟实验得出;(2)排放系数α通过煤岩吸附实验结合火区实地勘测得出;(3)排放通量通过对火区现场煤自燃气体排放及环境因素的实时监测得出;(4)排放系数β通过对遥感图像裂隙信息的提取得到。上述两种计算模型在我国乌达实验区进行了实际应用,并对其可实现性进行了检验。     

Study on the gas-curtain generation characteristics by the multiple gas jets in a liquid-filled tube

To further understand the gas-curtain generation characteristics during the launching process of the underwater guns, a simulated gas-injector with multiple nozzles is designed and the expansion process of these multiple combustion-gas jets is experimentally captured. Experiment results indicate that, with turbulent mixing between the gas jets and the liquid medium, the gas curtain is generated in the observation chamber. Based on the experiment, a three dimensional unsteady model is established to simulate the expansion process of the multiple jets. Numerical result shows, with the injection of the gas jets, pressure declines in the Taylor cavity along the axial direction at the beginning. During the expansion process, the multiple jets contact and interact with each other, and pressure rises in the mixing area. After merging, backflow vortexes interact and converge, and the vortexes move along the axial direction with the expansion of the combustion gas jets.     

Magnetic Susceptibility and Heavy Metals Distribution from Risk‐cultivated Soil around the Iron–Steel Plant,China

Magnetic susceptibility is a non‐conventional way that can be used for evaluating proxy soil heavy metals pollution. The paper monitors available heavy metals (Cu, Fe, Zn, and Mn) present in cultivated soils around iron–steel plant by soil magnetic susceptibility. Our study was located in an area with high pollution with small grid density of 250 m in China. Results showed that low field magnetic susceptibility was significantly correlated with available Cu, Zn, and Mn. No clear association exists between magnetic susceptibility and available Fe, soil organic matter, pH. Frequency dependent susceptibility >5% suggests the possible presence of super‐paramagnetic particles, fly ashes produced during coal combustion.     

综放采空区特性与氧浓度分布关系研究

在现场束管监测实验的基础上,分析总结了综放采空区特性。根据计算流体力学原理,采用FLUENT数值模拟计算软件,针对综放采空区的不同特性,分别对采空区氧化带和窒息带的关键划分指标＂氧浓度＂进行数值模拟。将模拟结果与实测结果进行比较,讨论了在考虑综放采空区不同特性情况下的数值模拟结果对采空区自燃＂三带＂,即＂散热带＂、＂氧化带＂和＂窒息带＂划分的影响。结果表明,综放采空区特性对于氧浓度分布起着非常重要的作用,在数值模拟过程中必须予以考虑;忽略采空区特性的数值模拟结果与实测结果存在较大差异;模拟结果的精确与否取决于对问题的了解程度和边界条件的设定精度。     

Lead concentrations and isotopes in aerosols from Xiamen, China

To investigate the magnitude and origin of lead (Pb) pollution in the atmosphere of Xiamen, China, 40 aerosol samples were collected from the coast of Xiamen from January to December 2003. All these samples were measured for Pb isotopic compositions (²⁰⁸Pb/²⁰⁶Pb = 2.10897 ± 0.00297, ²⁰⁷Pb/²⁰⁶Pb = 0.85767 ± 0.00159, n = 40) using a Multi-collector-Inductively Coupled Plasma Mass Spectrometer (MC-ICPMS). Thirty-five out of forty samples were also measured for Pb concentrations (79.1 ± 38.3 ng/m³, n = 35) by Atomic Absorption Spectroscopy (AAS). The results indicate that the Pb concentrations display significant seasonal variations while Pb isotopic ratios remain relatively constant. The Pb concentrations were high in January and February, abruptly decreased in March, remained relatively constant (but low) from April to August, and then gradually increased from September to December. This corresponds to the rainless climate in winter and rain scavenging in summer. The higher Pb concentration of Xiamen aerosols in winter and spring may be also caused by long-range transferred anthropogenic Pb during the northeastern monsoon seasons. Although the use of leaded gasoline in Xiamen was banned in 2000, our new data indicate that the Pb annual concentrations of aerosols in Xiamen increased about 12% when compared to the data measured between 1991 and 1993. Thus, Pb pollution in the atmosphere of Xiamen has not receded even after the phase-out of leaded gasoline. Our results further confirm the previous studies’ conclusion that the primary source of atmospheric Pb in China, especially in South China, is the vast combustion of lead-containing coal, not leaded gasoline.     

桦甸油页岩半焦基础理化特性

油页岩半焦是油页岩干馏的主要副产物,半焦的合理利用是油页岩综合利用的基础。利用自建的实验台制备了吉林省桦甸3个矿区油页岩半焦样品,采用X射线衍射仪分析半焦样品的矿物组分,采用电感耦合等离子体原子发射光谱(ICP-AES)测定了半焦样品中部分痕量元素的含量并分析其富集特性,采用热重分析仪详细研究了各半焦样品的燃烧特性,测定了油页岩半焦的灰分特性、比热、密度、导热系数、可磨性等物性参数。研究表明:桦甸油页岩半焦属于高灰分、低热值和具有中等程度结渣倾向的劣质燃料;半焦中含有较多的石英、方解石、伊蒙混层等矿物质;半焦中痕量元素含量相对较高,并且表现出强富砷特性。利用燃烧实验数据建立的半焦燃烧动力学模型表明,半焦燃烧反应在不同的温度范围内具有不同的反应级数。     

Characterization of Regional Combustion Efficiency using ΔXCO: ΔXCO2 Observed by a Portable Fourier-Transform Spectrometer at an Urban Site in Beijing

Measurements of column-averaged dry-air mole fractions of carbon dioxide and carbon monoxide, CO₂ (XCO₂) and CO (XCO), were performed throughout 2019 at an urban site in Beijing using a compact Fourier Transform Spectrometer (FTS) EM27/SUN. This data set is used to assess the characteristics of combustion-related CO₂ emissions of urban Beijing by analyzing the correlated daily anomalies of XCO and XCO₂ (e.g., ΔXCO and ΔXCO₂). The EM27/SUN measurements were calibrated to a 125HR-FTS at the Xianghe station by an extra EM27/SUN instrument transferred between two sites. The ratio of ΔXCO over ΔXCO₂ (ΔXCO:ΔXCO₂) is used to estimate the combustion efficiency in the Beijing region. A high correlation coefficient (0.86) between ΔXCO and ΔXCO₂ is observed. The CO:CO₂ emission ratio estimated from inventories is higher than the observed ΔXCO:ΔXCO₂ (10.46 ± 0.11 ppb ppm^?1) by 42.54%–101.15%, indicating an underestimation in combustion efficiency in the inventories. Daily ΔXCO:ΔXCO₂ are influenced by transportation governed by weather conditions, except for days in summer when the correlation is low due to the terrestrial biotic activity. By convolving the column footprint [ppm (μmol m^–2 s^–1)^–1] generated by the Weather Research and Forecasting-X-Stochastic Time-Inverted Lagrangian Transport models (WRF-X-STILT) with two fossil-fuel emission inventories (the Multi-resolution Emission Inventory for China (MEIC) and the Peking University (PKU) inventory), the observed enhancements of CO₂ and CO were used to evaluate the regional emissions. The CO₂ emissions appear to be underestimated by 11% and 49% for the MEIC and PKU inventories, respectively, while CO emissions were overestimated by MEIC (30%) and PKU (35%) in the Beijing area.     

浙江省衢州市玳堰矿区石煤自燃地质环境治理

石煤自燃治理是我国地质环境治理的一大难题,衢州市玳堰石煤矿区石煤自燃已造成严重的地质和生态环境问题。为了有效治理矿区石煤自燃,恢复矿区生态环境,采用密闭采矿硐口、石煤自燃点削坡以及黄泥密闭的＂隔氧灭燃＂治理方法。治理效果表明,白坑5号、3号矿和煤山底矿石煤自燃已得到控制;矿区大气二氧化硫监测结果小于0.03mg/m3,地表水SO42-含量从7045.6mg/L降低到399mg/L,治理效果良好,为今后类似废弃矿山石煤自燃的治理提供了参考。     

民用煤室内燃烧条件下多环芳烃的排放特征

民用燃煤是我国最大的室外和室内空气污染源.为了研究不同煤种在民用燃烧条件下多环芳烃(PAH)的排放特征,对5种成熟度不同的煤种(4种烟煤和1种无烟煤)以蜂窝煤形式燃烧产生的烟气进行采集,对其中24种PAHs进行定量分析,并与原煤的二氯甲烷(DCM)抽提物进行对比.结果表明,不同煤种的PAH排放因子差别显著,无烟煤的排放因子比烟煤低3个数量级,24种PAHs总和仅为184 μg/kg,烟煤则为136～408 mg/kg;原煤PAH抽提率的情况与之相似,无烟煤为4 mg/kg,烟煤为96～156 mg/kg.各种类型PAH(母体PAH、甲基PAH和含O/S-PAH)所占比例在不同煤种之间存在差异,但在烟气中和原煤抽提物的情况一致,说明民用燃煤前后PAH具有一定的继承性.通过4组毒性当量参数的比较,发现无烟煤燃烧烟气中的PAH毒性当量比原煤抽提物明显减少,而烟煤则表现为不同程度的增加.     

高精度磁测在陕北煤田火烧区的应用

通过对陕北某井田实测地面高精度磁测异常的解译,总结利用高精度磁测有效圈定煤层自燃边界的方法和经验,并通过钻孔加以验证,为以后此类工作提供了借鉴.