纺织工业粉尘爆炸危险区域划分方法

根据国家标准,分析了爆炸性粉尘环境危险区域划分的方法和步骤,以粉尘释放源释放频率和形成爆炸混合物的可能性为指标,给出了危险区域划分方法,并以某纺织企业为例进行了说明,所得结果对纺织企业的安全生产具有借鉴意义。     

可燃气体燃爆特性综合试验装置构建与甲烷试验

为研究半开敞空间内可燃气体爆炸过程,设计带有泄压面的气体爆炸室,并在此基础上构建一套可燃气体燃爆特性综合试验装置。运用该试验装置,研究预混塔内甲烷气体分层现象以及甲烷爆炸浓度与最小点火能之间的变化规律。甲烷分层试验结果表明:静置一段时间后,预混塔中甲烷浓度随高度的增加而增大。最小点火能试验结果显示,当甲烷的试验爆炸体积分数在10%～13%时,其浓度与点火能之间呈现比较平缓的变化关系,而当其体积分数小于10%或大于13%时,浓度稍微变化,其点火能将发生明显变化。     

土介质炸点痕迹反演爆源特征的研究

论述了土介质炸点痕迹特征参量及其控制影响因素,通过对国内外现有研究成果的再分析和有效利用,得到爆源特征与炸点痕迹特征参量之间的关系。在此基础上,建立利用土介质上的炸点痕迹反演爆源特征的方法,并实现编程计算。通过实例分析说明了该方法的可行性。     

“8·29”充装台充装现场氧气瓶爆炸事故原因分析

介绍了较为少见的充装台充装过程中氧气瓶爆炸事故,描述了事故爆炸后的现场。对爆炸气瓶碎片进行化学成分分析、机械性能、金相试验、内壁附着物化学成分分析和能谱分析。通过分析认定,由于误操作油脂混进氧气瓶,高压氧气和油脂接触发生剧烈的自燃氧化放热,使瓶内的氧气迅速升温升压,超出气瓶承压极限导致气瓶爆炸。结合工作经验,提出要严格气瓶充装前的检验,加强气瓶使用和经销单位的安全监管等防范措施和建议,对氧气瓶的安全管理具有参考价值和实际意义。     

蒙德法在火电厂液氨储罐评价单元的应用

火电厂液氨储罐单元存在大量高纯度的液氨,一旦发生火灾、爆炸,后果极其严重。为了研究液氨储罐的火灾爆炸危险性及毒性,在对火电厂液氨储罐危险性辨识的基础上,依据液氨储罐单元的主要参数,运用蒙德法分别确定评价中需要的各种危险性系数,从而进行各项指标计算,查询危险性等级表,将各项指标进行等级划分,结论表明各项危险等级都很高。在得出结论基础上,进行安全措施补偿评价,补偿后的各种危险等级均降低,可见采取补偿措施后能够一定程度的降低火灾、爆炸、毒性的危险性,防止事故的发生。     

一种异形结构传爆药起爆威力实验研究

旨在研究一种新型高能传爆药装药结构,根据冲击波汇聚技术、拐角效应理论和有效装药理论等,设计了一种异形结构传爆药。利用主装药轴向钢凹法对多点同步起爆网络起爆的该异形结构传爆药柱起爆威力进行了实验研究。对实验数据进行对比分析,结果表明在达到相同起爆效果的情况下,利用多点同步起爆网络起爆的该异形结构传爆药柱相对于普通圆柱形传爆药柱的用药量有较大幅度的降低。研究成果对解决钝感弹药的起爆问题具有重大的现实意义。     

液化石油气钢瓶爆炸事故分析与思考

我国液化气钢瓶使用量大而广,液化气钢瓶事故时有发生。由于使用者安全意识不强,气瓶违法充装、超期不检、违规检验或修理改造报废气瓶等问题导致的气瓶事故仍居高不下,是造成我国液化气钢瓶事故的主要原因。另外,违法将二甲醚掺入液化石油气钢瓶,液化石油气钢瓶管理混乱也是事故发生的主要原因。该文在分析事故原因的基础上,提出调换液化石油气钢瓶,在使用时有人看管,液化石油气钢瓶必须直立使用,放置位置不要靠近热源等几条液化石油气安全使用要点分析与事故处置。以加大对液化石油气钢瓶事故灾害预防、隐患治理工作,加大对用户安全使用常识的宣传教育工作,杜绝事故的发生。     

Reconsideration on the effect of nitrogen on mixed culture polyhydroxyalkanoate production toward high organic loading enrichment history

Effect of nitrogen on mixed culture PHA production was reconsidered. Enrichment history of PHA accumulating culture was discussed. Higher PHA content and biomass growth were achieved in presence of nitrogen. Enrichment strategy toward higher PHA accumulation was investigated. Microbial community succession in PHA accumulation phase was investigated. In most of the operating strategies for mixed microbial cultures polyhydroxyalkanoate (PHA) production, moderate organic loads and low nitrogen concentrations are used, however, the real waste streams contain variable concentrations of carbon and nitrogen. To evaluate the effect of enrichment history on PHA producer and production the various carbon and nitrogen levels were utilized during the accumulation phase. Different operating strategies were applied in three sequencing batch reactors (SBRs) subjected to aerobic dynamic feeding. The maximum PHA production of the enriched cultures under nutrient excess, limitation and starvation (Cmol/Nmol ratio of 8, 40 and ∞, respectively) was evaluated in batch assays. A higher PHA content and biomass growth were achieved in the nutrients presence in comparison to the nutrient starvation condition. The cultures from the SBR treated under short sludge retention time, high organic loading rate, short cycle length (SBR#3) and nutrient excess reached the maximum PHA content (54.9%) and biomass increase (38.9%). Under nutrient limitation, the negative biomass growth was observed under nutrient starvation because of the sampling loss. The succession of microbial communities in SBRs and batch assays was analyzed using terminal restriction fragment length polymorphism. The SBR#3 had the best overall PHA production performance considering its high PHA content and productivity in all nutrient content, it indicates that nitrogen has a substantial impact on PHA yield especially when high organic loading rate enrichment history is involved.     

Influence of vacuum degree on the effect of gas explosion suppression by vacuum chamber

In order to study the influence of vacuum degree on gas explosion suppression by vacuum chamber, this study used the 0.2 mm thick polytetrafluoroethylene film as the diaphragm of vacuum chamber to carry out a series of experiments of gas explosion suppression by vacuum chamber with the vacuum degree from −0.01 MPa to −0.08 MPa. The experimental results show that: under the condition of any vacuum degree, vacuum chamber can effectively suppress the explosion flame and overpressure; as vacuum degree changes, the effect of gas explosion suppression using vacuum chamber is slightly different. Vacuum chamber has obvious influence on propagation characteristics of the explosion flame. After explosion flame passes by vacuum chamber, the flame signal weakens, the flame thickness becomes thicker, and the flame speed slows down. With the increase of the vacuum degree of vacuum chamber, the flame speed can be prevented from rising early by vacuum chamber. The higher the vacuum degree is, the more obviously the vacuum chamber attenuates the explosion overpressure, the smaller the average overpressure is, and the better effect of the gas explosion suppression is. Vacuum chamber can effectively weaken the explosion impulse under each vacuum degree. From the beginning of −0.01 MPa, the vacuum chamber can gradually weaken explosion impulse as the vacuum degree increases, and the effect of gas explosion suppression gradually becomes better. When the vacuum degree is greater than −0.04 MPa, the increase of vacuum degree can make the explosion overpressure decrease but have little influence on the explosion impulse. Therefore, the vacuum chamber has the preferable suppression effect with equal to or greater than −0.04 MPa vacuum degree.     

Flame propagation in lycopodium/air mixtures below atmospheric pressure

Industrial processes are often operated at conditions deviating from atmospheric conditions. Safety relevant parameters normally used for hazard evaluation and classification of combustible dusts are only valid within a very narrow range of pressure, temperature and gas composition. The development of dust explosions and flame propagation under reduced pressure conditions is poorly investigated. Standard laboratory equipment like the 20 l Siwek chamber does not allow investigations at very low pressures. Therefore an experimental device was developed for the investigations on flame propagation and ignition under reduced pressure conditions. Flame propagation was analysed by a video analysis system the actual flame speed was measured by optical sensors. Experiments were carried out with lycopodium at dust concentrations of 100 g/m³, 200 g/m³ and 300 g/m³. It was found that both flame shapes and flame speeds were quite different from those obtained at atmospheric pressure. Effects like buoyancy of hot gases during ignition and flame propagation are less strong than at atmospheric conditions. For the investigated dust concentrations the flame reaches speeds that are nearly an order of a magnitude higher than at ambient conditions.