Safetygram-18安全程序-18

1、Safetygram-18安全程序-18Carbon Dioxide二氧化碳General概述Carbon dioxide is nonflammable, colorless, and odorless in the gaseous and liquid states. The gas is approximately one and one-half times as heavy as air. Carbon dioxide is a minor but important constituent of the atmosphere, averaging about 0.03% or 30

2、0 ppm by volume. Since dry carbon dioxide is a relatively inert gas, special materials of construction are not required. In the event moisture is present in high concentrations, carbonic acid may be formed and materials resistant to this acid should be used. High flow rates or rapid depressurization

3、 of a system can cause temperatures approaching the sublimation point (-109.3°F-78.5°C) to be attained within the system. Carbon dioxide will convert directly from a liquid to a solid if the liquid is depressurized below76 psia (61 psig). The use of materials which become brittle at low te

4、mperatures should be avoided in applications where temperatures less than -20°F(-29°C) are expected. Vessels and piping used in carbon dioxide service should be designed to the American Society of Mechanical Engineers (ASME) or Department of Transportation(DOT) codes for the pressures and

5、temperatures involved. 在液态和气态时二氧化碳是不可燃、无色、无嗅的。气体比空气重大约1.5倍。二氧化碳是空气的含量较小但很重要的组成成分，体积比平均约为0.03%或300 ppm。由于干燥的二氧化碳是相对不活泼的气体，不要求特殊的建材。在水蒸汽浓度很高的情况下，可以生成碳酸，这时应使用对该酸有抵抗力的材料。系统的高流速或迅速降压可以在系统内获得接近升华点(-109.3°F-78.5°C)的温度。 如果液体压力降到76 psia (61 psig)以下，直接从液态转化到固态。在预期温度低于-20°F(-29°C)的应用中应该避免使用

6、在低温下变脆的材料。用于二氧化碳设施的容器和管道要根据相关的压力和温度按照美国机械工程师协会(ASME)或交通部(DOT)的规范来设计。Carbon dioxide can be stored as a bulk liquid in large storage vessels with capacities up to 50 tons and larger. The liquid in the tank is maintained between 245 psig and 305 psig. When the tank pressure reaches 305 psig, a mechanic

7、al air-cooled refrigeration unit is activated which cools the tank contents and thereby reduces the pressure to about 295 psig. When pressure drops to 245 psig, a portion of the liquid is passed through a pressure buildup coil which vaporizes the liquid in the coil, and the resultant vapor is sent t

8、o the tanks vapor space until a tank pressure of 255 psig is attained. In isolated instances where carbon dioxide usage is extremely low, heat leak into the tank is sufficient to maintain the contents above 245 psig and a pressure buildup coil is not needed. The bulk storage tank can either supply g

9、as from the vapor space or liquid from the bottom of the tank. If warmer carbon dioxide gas is desired, vapor is withdrawn from the vapor space in the storage tank and superheated. Bulk storage tanks are filled by liquid transport trailers. 二氧化碳可以作为液体大量储存在容量大到50吨和更大的大型储存容器内。容器内的液体压力维持在245 psig和305 p

10、sig。当容器压力达到305 psig时，启动机械空气冷却制冷设备，使容器内容物降温，从而压力降到约295 psig。当压力降到245 psig时，部分液体流过一个压力积累蛇管，蛇管使其内部的液体蒸发，产生的蒸气送到容器的蒸气空间，直到容器压力达到255 psig。在二氧化碳用量极低的隔热场合，泄漏进容器的热量足以使内容物的压力维持在245 psig以上，因此不需要压力积累蛇管。大容量储存容器能够或者从蒸气空间供应气体，或者从容器底部供应液体。如果需要温度更高的二氧化碳气体，可以从蒸气空间提取出蒸气，并使其过热。由液体运输拖车来灌装大容量容器。Carbon dioxide is also pu

11、mped as a liquid into high-pressure cylinders which are filled by weight. The amount of carbon dioxide gas contained in a cylinder is determined by multiplying the weight of the liquid by the specific volume at 68°F (20°C) and 1 atmosphere pressure, (8.70 cu. ft./lb.). The vapor pressure o

12、f the liquid stored in the cylinder 68°F (20°C) is 816 pounds per square inch gauge (psig).Cylinders can be supplied with standard valves for gas withdrawal or with siphon tubes connected internally to the valves for liquid withdrawal. 还可以把二氧化碳泵入根据重量来灌装的高压钢瓶。液体的重量乘以在68°F (20°C)和1

13、个大气压时的比容(8.70 cu. ft./lb.)，就是在钢瓶内容纳的二氧化碳气体的数量。储存在68°F (20°C)的钢瓶内的液体的蒸气压是816磅每平方英寸（psig）。钢瓶可以配有用于气体提取的标准阀门或在内部连接到阀门的用于液体提取的虹吸管。Carbon dioxide is also stored and shipped as a liquid in cryogenic cylinders at reduced temperature and at a pressure of about 300 psig. 二氧化碳还可以作为液体在压力减小到大约300 psig

14、的低温钢瓶内储存和运输，The molecular symbol for carbon dioxide is CO2.二氧化碳的分子式是CO2。Toxicity毒性Carbon dioxide does not support life and may produce immediately hazardous atmospheres. At concentrations in excess of 1.5%, carbon dioxide may produce hyperventilation, headaches, visual disturbances, tremor, loss of

15、consciousness, and death. Symptoms of exposure in the concentration ranges of 1.55% may be highly variable but typical symptoms of carbon dioxide intoxication are listed under Exposure Reactions. 二氧化碳不支持生命，可以立刻产生危险的空气。在浓度超过1.5%时，二氧化碳可以造成换气过度、头痛、视力紊乱、颤抖、失去知觉和死亡。在1.5到5%的浓度中暴露的症状有很多种，但是二氧化碳中毒的典型症状列在“暴露

16、反应”中。If the concentration of carbon dioxide exceeds 10%, exposure may produce profound metabolic aberrations, disturbances of the central nervous system, and cardiac irritability; unconsciousness can occur without warning, preventing self-rescue. At much higher concentrations, carbon dioxide displac

17、es the oxygen in air below levels necessary to support life.如果二氧化碳的浓度超过10%，暴露可以造成复杂的代谢失常、中枢神经系统紊乱和心过敏；没有警告就会造成意识不清，阻止了自救。在更高的浓度下，二氧化碳取代了空气中的氧，氧浓度降到维持生命所必须的浓度以下。Exposure Limit暴露极限The TLV-TWA for CO2, as listed by American Conference of Governmental Industrial Hygienists and by the Occupational Safety

18、 and Health Administration, is 5000 parts per million, or 0.5%.The CAS # for CO2 is 124-38-9.正如美国政府工业卫生学者会议和职业安全和健康管理局所列出的，对于二氧化碳的TLV-TWA值是百万分之5000或0.5%。对于二氧化碳，CAS #是124-38-9。Threshold Limit Value-Time Weighted Average (TLV-TWA) is the time-weighted average concentration for a normal 8-hour workday

19、and 40-hour workweek, to which nearly all workers may be repeatedly exposed, day after day, without adverse effect.阈值极限-时间权重平均值(TLV-TWA)是对于正常的8小时工作日和40小时工作周的时间权重平均值，在该值下，大多数工人日复一日的重复暴露在其中而不会受到有害影响。Manufacture生产Carbon dioxide is produced as a crude by-product of a number of manufacturing processes. C

20、arbon dioxide is a by-product of steam reforming of methane, propane or naphtha. The fermentation of sugar to alcohol and the production of lime and sodium phosphate also generate carbon dioxide. Additionally, carbon dioxide exists in natural wells. Once the product has been isolated, impurities are

21、 filtered out, moisture is removed in driers, and the purified carbon dioxide is compressed for liquefaction.二氧化碳是作为许多工业生产过程的天然副产品生产的。二氧化碳是甲烷、丙烷或石脑油的蒸气重整的一个副产品。糖发酵成酒精和石灰和磷酸钠的生产也产生二氧化碳。另外，二氧化碳存在于天然井里。产品分离出来以后，过滤掉杂质，在干燥剂里去除水蒸汽，净化了的二氧化碳被压缩液化。Uses用途Liquid carbon dioxide is used widely in the food indust

22、ry for freezing meats, poultry, vegetables, and fruits. Solid carbon dioxide (dry ice) is used to cool meats prior to grinding and also to refrigerate meat and poultry during transit. Soft drinks, wines, and beers are produced using gaseous carbon dioxide for carbonation. Carbon dioxide is used in w

23、ater treatment to neutralize alkaline water. Liquid carbon dioxide is also used to increase recovery from oil and gas wells. Other industrial uses include the production of chemicals, plastics, rubber, metals, and electronic components.液态二氧化碳在食品工业中得到了广泛的应用，用于冷冻肉类、家禽、蔬菜和水果。固态二氧化碳（干冰）用于在粉碎之前给肉类降温，还用于在

24、运输过程中冷藏肉类和家禽。使用气态二氧化碳利用碳酸化作用生产软饮料、葡萄酒和啤酒。在水处理中，二氧化碳用于中和碱水。液态二氧化碳还用于油井和气井以增加开采。其它的工业用途包括生产化学品、塑料、橡胶、金属和电子元器件。Containers容器Bulk carbon dioxide is typically stored as a liquid in storage tanks with capacities of 6, 14, 26, and 50 tons. Tanks are insulated by polyurethane foam with a vapor barrier which

25、provides weather protection. The tanks are fabricated from carbon steel according to ASME Standards. Carbon dioxide is maintained below 305 psig by a refrigeration unit and above 245 psig with a pressure buildup coil so that carbon dioxide can be stored for an in definite period without venting. Sma

26、ller liquid quantities are stored and shipped in cryogenic liquid cylinders with a capacity of 384 pounds (3352 standard cubic feet). Cryogenic liquid cylinders are vacuum-jacketed and can hold product for long periods without venting. Cryogenic liquid cylinders can either supply liquid or gas and l

27、iquid. A typical cryogenic liquid cylinder is illustrated in Figure 1.大量的二氧化碳典型地作为液体储存在容量为6、14、26、和50吨的储存罐里。用聚亚安酯泡沫把储存罐和防止恶劣天气的蒸气屏障隔离开。按照ASME的标准用碳素钢制造储存罐。通过一个制冷装置把二氧化碳维持在305 psig以下，同时通过一个压力积累蛇管把二氧化碳维持在245 psig以上，这样不用通风二氧化碳就可以储存一定的时间。较小量的液体在容量为384磅（3352标准立方英尺）的低温液体钢瓶中储存和运输。低温液体钢瓶带有真空夹层，可以不用通风而长期储存产品。

28、低温液体钢瓶可以或者供应液体，或者供应气体和液体。一个典型的低温液体钢瓶如图1所示。Properties 性质Molecular Weight分子量 . 44.01Boiling Point沸点 l atm (sublimes升华) . -109.3°F (-78.5°C)Freezing Point凝固点 76 psia . -69.9°F (-56.6°C)Critical Temperature临界温度 . 87.9°F (31.0°C)Critical Pressure临界压力 . 1070 psia (72.9 atm)De

29、nsity密度, Liquid液体 -35°F (-37°C), 11 atm . 68.74 lb./cu. ft.Density密度, Gas气体 68°F (20°C), 1 atm . 0.115 lb./cu. ft.Density密度, Solid固体 -110°F (-79°C), 1 atm . 97.4 lb./cu. ft.Specific Gravity比重, Gas气体(Air空气 = 1) 68°F (20°C), 1 atm . 1.53Specific Gravity比重, Liqui

30、d液体 -35°F (-37°C), 11 atm . 1.10Specific Volume比容 68°F (20°C), 1 atm . 8.70 cu. ft./lb.Latent Heat of Sublimation潜在升华热 . 10900 Btu/lb. moleSolubility in Water在水中的溶解度 68°F (20°C), 1 atm . 87.8% by volumeExposure ReactionsConcentration浓度 Effect影响1% . Slight increase in br

31、eathing rate.呼吸频率稍微增加2% . Breathing rate increases to 50% above normal level. Prolonged exposure can cause headache, tiredness. 呼吸频率增加到正常水平以上50% 。持续暴露会导致头痛、疲劳。3% . Breathing increases to twice normal rate and becomes labored. Weak narcotic effect. Impaired hearing, headache, increase in blood p

32、ressure and pulse rate.呼吸增加到正常水平的两倍和变得吃力。弱麻醉作用削弱了听力，头痛，血压和脉搏增加。45% . Breathing increases to approximately four times normal rate; symptoms of intoxication become evident and slight choking may be felt呼吸增加到正常水平的大约四倍；中毒症状变得明显，可以感到轻微的窒息。510% . Characteristic sharp odor noticeable. Very labored breathin

33、g, headache, visual impairment, and ringing in the ears. Judgment may be impaired, followed within minutes by loss of consciousness.特征性的强烈气味显而易见。呼吸非常吃力，头痛，视力减弱和耳鸣。判断力下降，几分钟内失去知觉。50100%. Unconsciousness occurs more rapidly above 10% level. Prolonged exposure to high concentrations may eventually resu

34、lt in death from asphyxiation.意识不清在10%水平上发生得更加迅速。持续暴露于高浓度会最终导致由于窒息而死亡。Carbon dioxide is shipped and stored as a liquefied compressed gas in hollow steel and aluminum cylinders. The cylinders have a concave base which allows the cylinders to stand upright and are tapered to a small opening on the top

35、. The tapered or open end is threaded to receive a cylinder valve or other suitable outlet connection. Safety relief devices are part of the cylinder valve or the outlet connections. A threaded neck ring is secured to the tapered end of the cylinder to allow a protective cylinder cap to be installed

36、. Cylinders are manufactured according to Department of Transportation(DOT) specifications. Cylinders in carbon dioxide service are hydrostatically tested upon manufacture, and every five years thereafter at 5/3 times the service pressure.二氧化碳作为液化压缩气体在空心钢瓶和铝瓶中运输和储存。瓶子底座是凹陷的，这样钢瓶可以垂直站立。钢瓶顶部是锥形的，最上端有个

37、小开口。锥形或开口端车有螺纹，可以安装阀门或排气口接头。车有螺纹的颈环固定在钢瓶的锥形端，可以安装保护性瓶帽。按照交通部的规范制造钢瓶。用于二氧化碳的钢瓶在制造时经过了流体静力学测试，之后每五年进行一次在5/3倍工作压力下的测试。Gas Cylinder Valves气体钢瓶阀门The Compressed Gas Association and the American National Standards Institute have adopted a thread size of 0.825 inch14 external right-hand threads per inchdesi

38、gnated as valve connection No. 320 for cylinders. This fitting incorporates a flat nipple and fiber washer for making the gas-tight seal. See Figure 2. For additional information on cylinder valves, request Air Products Safetygram-23: Cylinder Valves.压缩气体协会和美国国家标准化学会已经采用了0.825英寸的螺距每英寸14个右手外螺纹指定它作为阀门

39、的第320号接头用于钢瓶。这种装置结合一个平面螺纹接头和纤维垫圈，用于制造气密密封。见图2。要得到关于钢瓶阀门另外的资料，请参考Air Products的安全程序-23：钢瓶阀门。Safety Devices安全装置Bulk liquid storage tanks are protected against excessive pressures, which may result from heat leak, by reseatable relief devices. Cryogenic liquid cylinders are equipped with reseat able rel

40、ief devices and are additionally protected with burst discs. Gas cylinders are protected from rupture due to fire by a frangible disc sometimes backed by a fusible metal with a melting temperature of about 212°F(100°C).使用可以复位的减压装置来保护大容量液体储存罐，以防止可能由热泄漏产生的过大的压力。低温液体钢瓶配备有可以复位的减压装置，另外还用破裂盘来保护钢

41、瓶。用破裂盘，有时后候后面还有一个熔化温度为212°F(100°C)易熔金属，来保护气体钢瓶，防止由于起火而破裂。Identification: Gas Cylinders鉴别：气体钢瓶Each cylinder is identified between the neck ring and shoulder by: 在颈环和肩部之间鉴别每个钢瓶的是通过：1. The DOT specifications (3A, 3AA,etc.) controlling the manufacture of the container, followed by the service

42、pressure rating in pounds per square inch.控制容器制造的DOT规格(3A, 3AA等)，随后是以磅每平方英寸为单位的工作额定压力。2. Serial number of the container.容器的序列号。3. Manufacturers symbol and the owners symbol.制造商的标志和所有者的标志。4. Month and year of the container manufacture.容器制造的月和年。5. Month and year of subsequent 5-year retest of the cont

43、ainer.容器随后五年一次重新测试的月和年。6. Original inspectors identification stamp.最初检查者的鉴别印记。The neck ring usually is identified by the owners symbol or name.通常通过所有者的标志或名字来鉴别颈环。Identification: Cryogenic Liquid Cylinders鉴别：低温液体钢瓶Each cryogenic liquid cylinder is identified with the following information stamped per

44、manently on the shoulder or top head of the jacket, on a permanently attached plate, or on the head protective ring.通过下列信息来鉴别每一个低温液体钢瓶，这些信息永久性地印在外壳的肩部或顶部上，印在一个永久性的附属板上，或者在顶部保护环上。1. DOT-4L followed by the service pressure rating in pounds per square inch. DOT-4L，随后是以磅每平方英寸为单位的额定工作压力。2. Serial number

45、and identifying symbol; location of the number to be just below or immediately following the DOT mark; location of the symbol to be just below or immediately following the number.序列号和鉴别标志；数字的位置刚好在DOT标记的下面或紧随其后；标志的位置刚好在数字的下面或紧随其后。3. Month and year of the container manufacture.容器制造的月和年。Shipment of Car

46、bon Dioxide: Bulk二氧化碳的运输：大量Carbon dioxide is transported to bulk supply systems by insulated liquid tankers which must conform to DOT Regulations as set forth in the Code of Federal Regulations, Title 49. DOT 103/4" x 103/4" nonflammable gas placards are required on the trailer.通过隔热液体罐车来把

47、运输到大量供应系统。液体罐车必须符合DOT规格，正如Code of Federal Regulations, Title 49里阐明的。在拖车上要求有DOT的103/4英尺x 103/4英尺的不可燃气体张贴。Shipment of Carbon Dioxide: Cylinders二氧化碳的运输：钢瓶The shipment of carbon dioxide gas cylinders by surface transportation must conform to DOT Regulations, Title49, which describes labeling and identif

48、ication required. A DOT 4" x 4" nonflammable gas label or tag is required for common carrier shipments. Figure 3 illustrates the label (black printing on green) that is required.通过水陆交通的二氧化碳气体钢瓶的运输必须符合DOT规范的49条，它说明了所要求的标签和鉴别。对于公用运输业者运输，要求贴有一个DOT的4英尺x4英尺的不可燃气体标志或标签。图3说明了所要求的标签。Cryogenic liqu

49、id carbon dioxide cylinders are shipped under DOT Exemption Number 7638. A copy of this exemption must be carried aboard each vessel, aircraft or motor vehicle used to transport the cylinders. Each cryogenic cylinder must be plainly marked on both sides near the middle, in letters at least two inche

50、s high on a contrasting background, “DOT-E7638.” The DOT 4" x 4" green nonflammable gas label or tag is also required for common carrier shipments. Shipments by air must conform with Title 49 Code of Federal Regulations(FAA Regulations). The official publication of the Department of Transp

51、ortation concerning transport of hazardous materials by any mode is 49 CFR.低温液体二氧化碳钢瓶运输的DOT免税号是7638。用于运输钢瓶的每个船舶、飞机或汽车上必须携带一个免税的拷贝。必须在每个低温液体钢瓶的两边靠近中间的位置上用至少两英寸高的字母在对比强烈的背景上标明：“DOT-E7638”。对于公用运输业者运输，也要求贴有一个DOT的4英尺x4英尺的不可燃气体标志或标签。空运必须遵守Title 49 Code of Federal Regulations(FAA Regulations)。49 CFR是交通部的关于

52、以任何方式运输危险物质的官方出版物。Safety Considerations对安全的考虑Carbon dioxide is stored and transported as a liquefied compressed gas. The following hazards are associated with liquefied compressed carbon dioxide.二氧化碳是以液态压缩气体的方式储存和运输的。同液化压缩二氧化碳相联系的是下列危险。1. High pressure involved in storage and service equipment.同储存和使

53、用设备相关的高压。2. Carbon dioxide is 1.5 times heavier than air and will not readily disperse in the atmosphere. Asphyxiation may be a hazard in confined areas. 二氧化碳比空气重1.5倍，在空气中不易扩散。窒息是在狭窄区域的危险。3. Carbon dioxide in high concentrations is toxic to humans. See the toxicity section for effects on humans.高浓度二

54、氧化碳对人体有毒。关于对人体的影响，见毒性部分。4. Vaporizing carbon dioxide can produce very cold temperatures. Spillage of liquid carbon dioxide on the skin can cause freeze burn or frostbite. Carbon dioxide, solid below 61 psig, is very cold and sublimes so quickly that prolonged contact with the skin causes freeze burn

55、 or frostbite.正在蒸发的二氧化碳会造成极低的温度。液体二氧化碳溅到皮肤上会导致冻伤。压力在61 psig以下的二氧化碳固体温度极低，升华得非常快，持续接触皮肤会导致冻伤。Buildings建筑物1. Provide adequate ventilation. 提供充分的通风。2. The atmosphere in areas in which carbon dioxide gas may be vented and collect should be tested with a portable or continuous monitoring carbon dioxide g

56、as analyzer to ensure ventilation is adequate.应该用移动或连续的二氧化碳监测分析仪来测试可能排出或积累二氧化碳气体的区域，以保证通风是充分的。Handling and Storage操作和储存1. Never drop cylinders or permit them to strike each other violently. 禁止使钢瓶摔倒或使它们彼此剧烈碰撞。2. Cylinders should be assigned a definite area for storage. The area should be dry, cool, a

57、nd well ventilated, and preferably fire-resistant. Keep cylinders protected from excessive temperatures by storing them away from radiators or other sources of heat. 应安排有确定的钢瓶存放区域。该区域应该使干燥、凉爽、通风良好，最好是防火的。远离散热器或其它热源，使钢瓶接触不到过高的温度。3. Cylinders may be stored in the open, but in such cases should be prot

58、ected against extremes of weather and from damp ground to prevent rusting. 钢瓶可以存放在室外，但应防止受到恶劣天气的影响，同时不能接触潮湿的地面，以防生锈。4. The valve protection cap should be left in place until the cylinder has been secured against a wall, a bench, or placed in a cylinder stand, and is ready to be used. 在钢瓶靠着墙壁、工作台固定或放置在钢瓶座准备使用之前，阀门保护帽要一直留