Thermal hazard accident investigation of hydrogen peroxide mixing with propanone employing calorimetric approaches

Hydrogen peroxide (H₂O₂), historically, due to its broad applications in the chemical industries, has caused many serious fires and explosions around the world. Its thermal hazards may also be incurred by an incompatible reaction with other chemicals, and a runaway reaction may be induced in the last stage. This study applied thermal analytical methods to explore the H₂O₂ leading to these accidents by incompatibility and to discuss what might be formed by the upset situations. Thermal hazard analysis contained a solvent, propanone (CH₃COCH₃, so-called acetone), which was deliberately selected to mix with H₂O₂ for investigating the degree of thermal hazard. Differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2) were employed to evaluate the thermal hazard of H₂O₂. The results indicated that H₂O₂ is highly hazardous while mixed with propanone, as a potential contaminant. The time to maximum rate (TMR) was used as emergency response time in the chemical industries. Therefore, TMR of H₂O₂ was calculated to be 70 min for runaway reaction (after T₀) and TMR of H₂O₂/propanone was discovered to be 27 min only. Fire and explosion hazards could be successfully lessened if the safety-related data are properly imbedded into manufacturing processes.     

电袋复合除尘器中产生氧化性物质的研究

针对电袋复合除尘器前级电场电晕放电有可能会产生臭氧,而臭氧又迅速与烟气中NO反应生成NO2这一猜想,通过对实际工况下电袋复合除尘器中臭氧含量和NOX浓度进行的测试,得出电袋复合除尘器中并无臭氧产生,且NO2浓度也未增加。但烟气中NO2浓度已经接近除尘器PPS滤料在使用温度下(150℃)所能承受的最高限值,PPS滤料会因发生氧化而失效,缩短滤料使用寿命。     

矿用聚氨酯注浆材料阻燃及加固性能研究

为获得压缩强度和阻燃性能兼顾的聚氨酯注浆材料,通过L9(34)正交试验,研究Mg(OH)2含量、甲基膦酸二甲酯(DMMP)含量、异氰酸酯指数、辛酸亚锡含量对聚氨酯注浆材料的阻燃性能及压缩性能的影响。获得这种聚氨酯注浆材料的最佳制备条件。对比分析最佳制备条件试样及不加阻燃剂试样的热稳定性。结果表明:DMMP含量和Mg(OH)2含量对平均燃烧时间影响显著;Mg(OH)2还有补强加固作用,对压缩强度影响最为显著,其次为异氰酸酯指数。在Mg(OH)2,DMMP,辛酸亚锡质量分数分别为16%,24%和0.4%,异氰酸酯指数为1.10时,聚氨酯注浆材料兼顾阻燃性能和压缩性能,平均燃烧时间为13.9 s,压缩强度为19 MPa,其热稳定性明显优于不添加阻燃剂样品。     

理化因素对锰细菌Arthrobacter chlorophenolicus MN1409氧化Mn2+的影响

Arthrobacter chlorophenolicus MN1409是1株分离自锰矿样品的高效锰氧化细菌。为了建立该菌株氧化Mn2+的适宜条件,研究了接种量、装液量、摇床转速、温度、pH值、Fe2+初始质量浓度和Mn2+初始质量浓度等理化因素对其锰氧化效率的影响。结果表明,接种量、装液量、转速和Mn2+初始质量浓度在一定范围内变化对锰氧化率影响不大;而温度、pH值和Fe2+初始质量浓度变化对锰氧化率有较大影响。当接种量为4%,装液量为60 mL,温度为25℃,摇床转速为100r/min,pH值为7,且有一定的Fe2+存在时,Arthrobacter chlorophenolicusMN1409对锰的氧化效率最高。     

SO2对Ag/Al2O3催化剂上CH3OH还原NO性能的影响

用溶胶-凝胶混合法制备了Ag负载量为5%的Ag/A1₂O₃催化剂.研究了富氧条件下,SO₂对CH₃OH在催化剂上还原NO性能的影响.结果表明,反应气不含SO₂和H₂O时,NO还原活性温度较低,有显著量N₂O生成,这被归因为反应过程中,部分氧化态Ag被还原为金属Ag.添加SO₂或同时添加SO₂和H_{2相似文献}   

产酸脱硫反应器中碳硫比对群落生态特征的影响

通过产酸脱硫反应器处理高浓度含硫酸盐废水的连续流试验,从群落动态的角度研究碳硫比(COD/SO₄^2-)从4.2降低到2.0的过程中,pH值、氧化还原电位(ORP)、碱度(ALK)和末端产物(VFAs)组成、优势种群分布等群落生态特征的变化规律试验证明,在此过程中ORP和ALK提高,而pH值和VFAs中乙酸的分布比例降低,群落类型由高碳硫比稳定型转化为低碳硫比亚稳定型,但仍未改变乙酸型顶极群落的典型特征.     

产酸脱硫反应器中COD/SO42-比制约的群落生态演替规律

通过产酸脱硫反应器的动态试验和配套的静态试验,考察致变因子 COD/SO₄^2-比制约的乙酸型顶极群落的结构、优势种群的组成和生态演替的规律; 阐明乙酸型代谢和乙酸型顶极群落是产酸脱硫生态系统的典型特征;揭示乙酸型顶极群落内平衡与反馈调节的生理代谢机制,并以因变因子**pH值、氧化还原电位和碱度来表征生态演替过程中优势种群的三维实现生态位.     

磷酸三苯酯(TPP)和磷酸三(2-氯异丙基)酯(TCPP)诱导人胚肾细胞HEK293凋亡的机制研究

磷系阻燃剂对人体的潜在毒性作用引起了国内外研究者的广泛关注。肾脏是机体重要的排毒器官,若肾脏细胞受损,可能影响肾脏功能的正常发挥。本研究以人胚肾细胞HEK293为研究对象,结合传统毒理学实验,筛选出磷酸三苯酯(TPP)及磷酸三(2-氯异丙基)酯(TCPP)诱导人胚肾细胞HEK293凋亡的关键靶标基因p53。在此基础上采用分子对接模拟和光谱法分析发现,TPP和TCPP分别以嵌插方式和沟槽方式结合p53-DNA,改变基因片段的框架结构,启动分子起始事件,通过影响相关基因(Bax、Hrk、Bcl-2和Bad)的表达量,导致线粒体途径释放cyt c,最终激活Caspase 7实现细胞凋亡。研究结果阐明了此类污染物诱导凋亡的作用机制,为毒害化学品的污染防控提供理论依据。     

Emission reduction and profit-neutral permit allocations

The present paper addresses two policy objectives: to implement a market for pollution permits and to make regulation acceptable for businesses. Profit-neutral permit allocations are defined as the number of permits that the regulator should give for free so that post-regulation profits (i.e. a firm's profits in the products market plus the value of the allowances granted for free) are equal to pre-regulation profits. The proposed model is developed by assuming that firms use polluting technologies and compete “à la Cournot”. The paper demonstrates that a low number of free allowances is sufficient to meet these two goals. Moreover, the regulator can fully offset losses, even when the reduction in emissions is high, provided that the sectors concerned are not monopolies, both for isoelastic and linear demand functions.     

Do energy prices affect employment? Decomposed international evidence

This paper analyzes the energy price-employment nexus and contributes to the literature by showing that it is important to decompose the regulatory effect into demand, cost, and factor-shift effects. This is done by means of a cross-country multi-sectoral dataset. The results show that both rising energy prices and shadow prices of energy have no significant effect on net employment when the manufacturing sectors only are analyzed. While finding significant variations across countries, the average employment effects become significantly positive once jobs in the economy as a whole are considered. This change is driven mainly by larger positive cost effects, which more than offset the negative demand effects and reductions in the positive factor-shift effects. Moreover, the paper reveals that the often implemented approach of using a simple regulation regressor, instead of decomposing the employment effect, can result in biased estimates.