快速检测一氧化碳气体的方法探讨

如何快速监测一氧化碳气体,对安全工作、生产是极其重要的。本文主要讲述了一种新的检测方法即一氧化碳被动式检气管法。该方法基于气体分子扩散定律和化学吸收反应原理。检气管内的惰性载体涂渍上对一氧化碳有特效的显色剂:;氯化钯-稳定剂G-浓硫酸体系。一氧化碳通过检气管端口扩散进入管内,与惰性载体上的显色剂发生反应,从而产生颜色变化。检气管显色长度的平方与一氧化碳浓度及采样时间的乘积在80-800mg/m3范围内成线性关系,从而求出环境中一氧化碳的时间加权平均浓度,快速测定一氧化碳气体的浓度。     

微量分析氯乙烯检测管的研制

为了快速、简便、有效地测定作业环境中氯乙烯单体的浓度,提高环境质量,保护操作者身心健康,我们研制了氯乙烯检测管。现将研制情况简介如下。 检测原理 氯乙烯检测管由反应管和检知管组成。见图一 图一氯乙烯检测管 反应管主要装有在载体硅胶上添加铬酐和浓酸的混合液制成的氧化剂和白色去除剂。 检知管装有在载体硅石上添加二甲基黄的乙醇溶液制成的检知剂。     

气体检测器中扩散过程的模拟计算

从费克和二定律出发,推导了气体在装有固体颗粒的小直径圆形管中有限扩散距离内扩散－反应过程的浓度分布表达式以及气体深度与扩散时间和扩散距离的关系。得出在一定的扩散时间内,气体浓度与扩散深度之间为抛物线关系;一定浓度的气体通过固体颗粒层扩散－反应时,其扩散深化度的平方与扩散时间的比值为常数。理论分析与实验结果完全符合。     

氮氧化物的治理

一、概述氮氧化物(NO_x)废气俗称“黄龙”,是一种破坏动植物生长,腐蚀设备和建筑物,严重危害人体健康的有害性气体。当浓度高时呈现棕黑色。其中一氧化氮(NO)与人体血液中血红蛋白结合成不活泼的氧化氮血红蛋白,引起组织缺氧。二氧化氮(NO_2)刺激肺和气管引起咳嗽,血压下降及神经系统麻痹,最后由于血液变质而引起死亡,当浓度超过450～500毫克/立方米时,短时间立即死亡。人类活动产生的NO_x主要来源于燃烧、机动车排气以及某些化工过程。全世界排入大气的NO_x每年约为5千万吨。NO_x在大气中平均滞留时间约为     

纳米光触媒降解低浓度氨气效能检测方法开发

开发了一种低成本快速创新的检测方法,主要装置为紫外线/可见光分光光度计及石英比色槽,较以往使用气相层析/质谱仪、傅立叶转换红外线光谱仪检测光触媒材料对气体降解效能简单又快速.实验时先将特定浓度气体注入一个密闭的石英比色槽中,再将比色槽置入紫外线/可见光分光光度计内进行检测,以获得特定浓度气体吸收光谱图及制备检量线,氨气检量线浓度范围为1×10-6～4×10-5.在光触媒材料进行异相光催化降解氨气效能分析检测时,将两种TiO2纳米触媒材料定量在石英基板上,置入比色槽内并注入氨气.同时将比色槽用UV光照射,进行降解实验,随后再将比色槽用紫外线/可见光分光光谱仪进行测试,由吸收光谱图中吸收强度,比对检量线,获得气体浓度变化以及光触媒材料对气体的降解效率.实验结果显示,真空潜弧合成系统自制的SANSS-TiO2光触媒,可将氨气的浓度降至原有的10.18%,商用纳米TiO2,仅能降至原有的49.7%.本研究已成功的建立简单,快速可靠的解低浓度氨气效能检测技术.     

合成氨催化剂升温还原水汽浓度分析小结

0前言 目前，氮肥行业的合成氨催化剂还原水汽浓度分析多采用烧碱石棉吸收称量法，它较以往的电石法分析时间短、数据较为精确。其原理是将一定体积的出塔气体通过碱石棉吸水前后的增量，计算得到出塔气体中水分的浓度。分析原理较为简单，但实际操作中有多种因素影响称量值。     

电镀工厂废气治理

从大气污染的角度看,电镀行业和一些主要的引起大气污染的行业如电力、冶金、化工等相比,它的排放量小得多,排放污染物的品种较少,其影响通常只限于电镀工厂周围的局部地区。我国目前电镀行业排放的大气污染物质主要是由硝酸分解产生的氧化氮,氧化氮有毒,对人体与环境有害。这里指的氧化氮包括一氧化氮与二氧化氮。一氧化氮是无色气体,二氧化氮则是红棕色的气体。电镀厂排放的氧化氮中以二氧化氮居多,因此俗称黄龙。虽然废气数     

我国水体中硝酸盐的污染现状及危害

我国水体中硝酸盐污染日益严重,水体中硝酸盐浓度过高会导致一系列的人类健康和环境风险。饮用水中高浓度的硝酸盐含量会增加人类患有高铁血红蛋白和"蓝婴综合征"的风险。过高的硝酸盐会诱发相邻地表水体的富营养化,藻类在活动过程中会产生毒素和减少水体的溶解氧含量,从而影响该区域的生物多样性。此外,硝酸盐在反硝化过程中会产生温室气体二氧化氮。     

钢铁合金及中低碳铬铁中磷含量的检测方法

根据国家标准与相关文献中磷的检测原理,本文研究了一个适用于钢铁合金及中低碳铬铁中磷含量的测定的更简便快速的检测方法,分别探讨了比色波长、显色时间、反应温度、酸度等因素对检测结果的影响,对检测条件进行了优化。在一定条件下,加入试剂后,不需要进行长时间的等待即可以直接对样品进行测定,可以节省大量时间。通过研究方法的准确性和稳定性,发现磷元素浓度在0～0.5μg/m L(非上限)范围内具有比较好的线性相关,且分析结果稳定可靠。     

轮胎快速充气嘴

由潘欣宝申请的专利 (专利号　 992 2 2 0 5 7,公布日期　 2 0 0 0 0 6 0 7)“轮胎快速充气嘴” ,其特点是由一个气管组成 ,气管上有一个与之连通的进气管 ,气管内安装了气门扳手。这种轮胎快速充气嘴结构简单 ,使用方便 ,可快速充气 ,并防止气体泄漏轮胎快速充气嘴     

气体泡沫驱油研究进展

气体泡沫驱油是在水驱油、化学驱油后再次进行驱油的主要手段。主要介绍了近年来研究较多的气体泡沫驱油的研究进展,包括氮气泡沫驱油、空气泡沫驱油、二氧化碳泡沫驱油、甲烷泡沫驱油四种驱油方式,对上述四种方法进行了评价和比较,并对今后的研究方向提出建议。     

Ethylene recovery from low grade gas stream by adsorption on zeolites and controlled desorption

Carbon dioxide was partially removed from a nitrogen stream, which also contained some ethylene, by adsorption on a 4A (Na-A) zeolite. The treated nitrogen stream was then passed over a 13X (Na-X) zeolite bed upon which ethylene and any remaining carbon dioxide were adsorbed. Ethylene was recovered by desorption at 68 Pa pressure into a slow flow of nitrogen as stripping gas. The ethylene concentration in the extracted gas was extremely dependent on the nitrogen flow-rate, whereas the concentration of carbon dioxide remained practically constant. Thus, it was possible to obtain a gas mixture greatly enriched in ethylene with a reasonably low content of carbon dioxide.     

光波导二氧化氮气敏传感元件的研究

本文用离子交换法制备K+交换玻璃光波导元件,并在其表面固定纳米级敏感层酞菁铜(CuPc)薄膜,利用光波导气体检测系统对NO2气体进行测试.结果表明,该传感元件常温下对NO2等气体有快速、可逆的响应,并具有重现性好,灵敏度高等特点.     

ECD检测器在痕量氧含量分析中的应用

使用气相色谱仪电子捕获检测器（ECD）检测大型空分装置所产高纯氮中痕量氧的含量,并与GB5831气体中痕量氧的测定方法进行对比,进行一些探索性研究。     

Composition of gaseous combustion products of polymers

The gaseous products generated by the flaming combustion of ten kinds of synthetic polymers and a kind of wood (cedar) under the same conditions (sample weight, 0.1 g; temperature, 700°C air flow rates, 50 and 100 l./hr) were quantitatively analyzed by infrared spectrophotometry, gas chromatography, and colorimetric tube method. The main hydrocarbons generated were methane, ethylene, and acetylene. The amount of acetylene generated by the flaming combustion of polymers was much larger than the amount of acetylene formed by pyrolysis at 700°C in nitrogen. Acetylene increased in quantity with increasing air. For nitrogen compounds, hydrogen cyanide was generated from every polymer containing nitrogen used, but ammonia was detected only for nylon 66 and polyacrylamide. Nitrogen monoxide and nitrogen dioxide were detected only in small amounts. Nitrous oxide was detected in the gaseous products generated by the nonflaming combustion of urea resin and melamin resin. It was also found that about 70% of the nitrogen in N-66 and PAA was converted into nitrogen gas (N₂) by combustion under the conditions described above.     

Comparison between the shock wave and chemical initiation in detonation of acetylene—oxygen mixtures

Detonation of different compositions of acetylene-oxygen mixtures by both chlorine gas injection and a shock wave as initiators is studied in this research. The chlorine gas is injected into the detonation tube through a reticular plate nozzle at the moment when a thin aluminum foil separating the injection system from the detonation tube is torn by a pressurized nitrogen gas. The results of experiments show that chemical initiation may be as effective as direct initiation of detonation and, therefore, replace more complicated methods of initiation. The best results are obtained in acetylene— oxygen mixtures with the molar ratio of 1: 1.     

糖精钠生产过程中废气的回收利用研究与探讨

在糖精生产过程中有氨气、氯化氢、二氧化氮、二氧化硫等废气放出。其中氨气用水吸收生成的氨水可吸收氯化氢、二氧化氮,所得溶液经处理可制成氮肥再利用;二氧化硫气体经洗涤后,用柠檬酸钠缓冲溶液吸收,再经解析、干燥、压缩后得到二氧化硫液体,然后供生产使用。     

The reaction of low levels of nitrogen dioxide with methyl linoleate in the presence and absence of oxygen

The reaction of methyl linoleate with low levels of nitrogen dioxide in a carrier gas, such as helium or air, at nitrogen dioxide concentrations ranging from 2 to 228 ppm was studied and the products formed were monitored. In both aerobic and anaerobic conditions, low concentrations of nitrogen dioxide reacted with methyl linoleate predominately to form allylic products. When a 1∶1 mixture of methyl palmitate/methyl linoleate was layered over an aqueous buffer and a nitrogen dioxide stream was passed from underneath, so that the stream passed through the aqueous layer before contacting the organic layer, allylic products again predominated. In the absence of air, the allylic products consisted of allylic nitro and nitrite derivatives of linoleate, whereas in the presence of air, allylic hydroperoxides were the principal products. The findings suggest that fatty acids with doubly allylic hydrogen atoms react preferentially by a hydrogen atom abstraction reaction rather than by the addition of nitrogen dioxide to a double bond.     

Separation of CO2/N2 Gas Mixture through Carbon Membranes: Monte Carlo Simulation

Abstract

Monte Carlo simulation method is employed to investigate separation behavior of gas mixture composed of carbon dioxide and nitrogen through a model carbon membrane under the different conditions. The simulation gives insight into the separation mechanism to a certain extent, which is based on the loading and diffusion of carbon dioxide and nitrogen in the carbon membrane with different pore size. The simulation results indicate that the carbon dioxide can be adsorbed on the surface of membrane wall more strongly, whereas the diffusion rate of nitrogen is more prominent. When the separation condition alters, the influence of the two main factors mentioned above on transport of gas molecules in membranes becomes different. Therefore, the equilibrium selectivity of nitrogen and carbon dioxide changes correspondingly.     

The influence of sorption processes on gas stresses leading to the coal and gas outburst in the laboratory conditions

The seepage of gas through coal and in particular through coal briquettes has already been a quite well known phenomenon. This also refers to its influence on certain initial conditions of coal and gas outbursts such as threshold values of so called gas stresses. In turn a detailed research on the influence of sorption processes on these conditions has been neglected until now. There is, however, an opinion that (fast) desorption is crucial for rock and gas outburst initiation and continuance, although many examples contradict such a thesis. The goal of the studies described here was to investigate a part of this ambiguity, namely the influence of sorption processes on gas stresses leading to coal and gas outbursts carried out in laboratory conditions.A series of laboratory experiments concerning provoking coal and gas outbursts was conducted. Coal briquettes and two gases: nitrogen and carbon dioxide were used. The experimental data was computed out into the gas stresses and the most important information was extracted. The obtained results showed that in experiments with nitrogen slightly higher gas stresses and thus more intensive provoking were needed in order to initiate outburst than in experiments with carbon dioxide. It indicates that sorption may be the factor that promotes outbursts. Comparative analysis implied also that for a given level of gas stresses the more sorptive the gas was, the longer it took to initiate an outburst. Moreover, in the experiments with nitrogen the global maximum of gas stresses occurred deeper inside of the briquette for any given time than in experiments with carbon dioxide. All the found differences were weak, though easily noticeable.