我国环境保护产业2004年发展评述

本文对2004年我国环境保护产业的发展情况及各重点领域市场作了分析,提出了目前存在的问题,并对2005年的产业发展趋势进行了展望。     

中国北方城市SO_2污染防治策略与总量控制方法

通过对中国北方城市SO2污染的季节性特点进行分析发现,减少采暖燃煤SO2排放,解决采暖期SO2污染,是SO2年日均值达标的关键。而改变采暖期能源结构和采暖方式,将传统燃煤取暖改为清洁能源取暖,提高电厂排放SO2占SO2排放总量中的比例,可以解决大多数北方城市采暖期SO2难以达标的问题。同时,通过电厂脱硫设施建设可有效控制SO2排放总量。     

Experimental investigations on direct injection diesel engines using grape seed oil methyl ester with different bowl geometries

In this paper, the performance of direct injection diesel engine was experimentally investigated under the influence of two different pistons’s geometry deep bowl combustion chamber (DBCC) and toroidal combustion chamber (TCC) compared with standard piston combustion chamber (SPCC) geometry. The experiments were carried out standard atmospheric conditions of 1.01325 bar and 30 ± 2 °C. The piston bowl was designed and developed without modifying the compression ratio of the engine. The investigations were carried out with B25 (25% GOME + 75% diesel), B50 (50% GOME + 50% diesel), B75 (75% GOME +25% diesel) and B100 (100% GOME) by volume blends for three different bowl geometries. The thermogravimetric analysis (TGA) was given the importance of higher in-cylinder temperature for the mass change of GOME leads to a more premixed phase of combustion. The results showed that DBCC has better combustion characteristics when compared with SPCC and TCC for all the blends. The B25 and B50 blends showed good combustion characteristics with DBCC and SPCC individually. While TCC showed average engine characteristics for all the blends categorically, the brake thermal efficiency for B25 blend confirmed a 4.7% higher than SPCC-diesel with DBCC piston, and the smoke, CO (Carbon monoxide), and HC (Hydrocarbon) are reduced by 9.2%, 30.7%, and 4.6%, respectively. Thus, the B25 blend in a DBCC piston engine was observed to be the distinction than other configurations. The results confirmed that the DBCC is a good option for B25 blend.     

对一次高炉煤气燃烧放散过程可吸入颗粒物浓度变化情况的分析

通过对环境空气中可吸入颗粒物浓度监测数据在一次高炉煤气燃烧放散过程中变化情况的分析,得出特殊的局地地形条件和局部地面气象条件可能造成污染物汇集和积累的结论,并就此提出高炉煤气燃烧放散时污染控制的建议。     

Analysis of emission characteristics of gas turbine engines with some alternative fuels

The paper concerns the comparative analysis of combustion characteristics of different alternative fuels such as Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK), cryogenic methane, bioethanol, biomethanol, biobutanol, dimethyl ether, biodiesel and conventional aviation kerosene Jet-A as well as analysis of emissions of NO_x, CO, CO₂, H₂O, HNO_y (y = 2,3) and organics for gas turbine engine operating on these fuels. The analysis has shown that the usage of all considered alternative fuels results in the increase of H₂O emission, compared to kerosene-fueled combustor, and, as consequence, in the growth of water vapor supersaturation that can increase the rate of the H₂O vapor condensation and enhance the formation of contrails and cirrus clouds in the atmosphere. The usage of all considered alternative fuels except FT-SPK, cryogenic methane and dimethyl can increase the CO₂ emission compared to using of kerosene. Emission of N-containing species can be reduced upon the usage of considered alternative fuels, except dimethyl ether, for which one can expect the increase in the emissions of HNO₂ and HNO₃ approximately by 10%. The emission of CO decreases for all fuels except biodiesel. The major decrease can be achieved upon the replacement of kerosene to bioethanol.     

氯盐阻化剂对煤自燃极限参数影响的试验研究

阻化技术是防治煤自燃的常用技术之一,研究阻化剂对煤自燃极限参数的影响是确定阻化效果的关键.采用程序升温试验,分析气煤和长焰煤的原煤样和经MgCl2、KCl、CaCl2、NaCl 4种阻化剂处理后的煤样耗氧速率和放热强度,并计算自燃极限参数和阻化率.结果表明:氯盐阻化剂可降低煤自燃低温阶段的煤耗氧速率和放热强度;4种阻化剂中对气煤煤样的平均阻化率最高是MgCl2 (63.6％),对长焰煤则是CaCl2 (45.9％),平均阻化率与自燃极限参数变化率呈正相关;气煤经MgCl2处理后自燃极限参数变化率最大,长焰煤经CaCl2阻化处理后的自燃极限参数变化率最大,对于气煤4种阻化剂阻化能力由大到小为MgCl2 KCl、CaCl2、NaCl,对长焰煤则为CaCl2、MgCl2、KCl、NaCl;氯盐阻化剂中MgCl2对气煤自燃极限参数影响最大,阻化效果好,而对长焰煤则为CaCl2.     

烟煤颗粒燃烧生成PM_(10)粒径分布研究

为了对流化床炉燃烧产生细颗粒物的排放加以控制,本实验采用烟煤,在马弗炉静态燃烧条件下,改变燃烧时间、燃烧温度、煤颗粒的尺寸,对收集到的煤灰进行粒度分析,得出不同燃烧工况对细颗粒物生成的影响。实验结果显示:随着燃烧时间越长,在煤完全燃尽之前,产生细颗粒物粒度呈二次多项式分布,先逐渐减小,达到最小值后,又缓慢增大;采用较高的温度,有助于降低可吸入颗粒物的产生;不同粒径原煤对产生PM10粒度影响较大。     

高瓦斯易自燃矿井漏风规律测试分析与研究

针对高瓦斯易自燃矿井瓦斯抽采引起采空区和破裂煤柱区域漏风增大的问题,以试验矿井金一、金二采区为例,运用通风压能测定与示踪技术相结合的联合检测,研究了矿井开采过程中的漏风规律。研究表明,在瓦斯抽采作用下试验矿井的工作面、邻近层、采空区以及密闭之间存在大量的漏风通道,漏风风速较大,达到6.53~12.26 m/min,漏风问题比较严重。从控制漏风角度提出综合治理方法可以掌握漏风规律,严控漏风通道,加强自燃监测,预防自燃事故。根据漏风规律测试结果,在主要漏风通道处,应用增挂帘布、喷涂堵漏材料、飞灰充填或水砂充填等措施堵漏控制漏风,保证了矿井的安全生产。     

Chemical looping combustion: A new low-dioxin energy conversion technology

Dioxin production is a worldwide concern because of its persistence and carcinogenic, teratogenic, and mutagenic effects. The pyrolysis-chemical looping combustion process of disposing solid waste is an alternative to traditional solid waste incineration developed to reduce the dioxin production. Based on the equilibrium composition of the Deacon reaction, pyrolysis gas oxidized by seven common oxygen carriers, namely, CuO, NiO, CaSO₄, CoO, Fe₂O₃, Mn₃O₄, and FeTiO₃, is studied and compared with the pyrolysis gas directly combusted by air. The result shows that the activity of the Deacon reaction for oxygen carriers is lower than that for air. For four typical oxygen carriers (CuO, NiO, Fe₂O₃, and FeTiO₃), the influences of temperature, pressure, gas composition, and tar on the Deacon reaction are discussed in detail. According to these simulation results, the dioxin production in China, Europe, the United States, and Japan is predicted for solid waste disposal by the pyrolysis-chemical looping combustion process. Thermodynamic analysis results in this paper show that chemical looping combustion can reduce dioxin production in the disposal of solid waste.     

Numerical study of the effect of obstacles on the spontaneous ignition of high-pressure hydrogen

A numerical simulation of the spontaneous ignition of high-pressure hydrogen in a duct with two obstacles on the walls is conducted to explore the spontaneous ignition mechanisms. Two-dimensional rectangular ducts are adopted, and the Navier–Stokes equations with a detailed chemical kinetic mechanism are solved by using direct numerical simulations. In this study, we focus on the effects of the initial pressure of hydrogen and the position of the obstacles on the ignition mechanisms. Our results demonstrate that the presence of obstacles significantly changes the spontaneous ignition mechanisms producing three distinct ignition mechanisms. In addition, the position of the obstacles drastically changes the interaction of shock waves with the contact surface, and spontaneous ignition may take place at a relatively low pressure in some obstacle positions, which is attributed to the propagation direction and interaction timing of two reflected shock waves.