Hazardous Chemicals Handbook 2 Episode 8 pot

Silver, platinum and Galvanized pipe or brass or tantalum, carbon, graphite bronze fittings for wet gas. At higher pressures use extra heavy black iron pipe. High- pressure steel, Monel or aluminium-iron-bronze valves Hydrogen selenide F T Aluminium and stainless steel are preferred but iron, steel or brass are acceptable Hydrogen sulphide F T Aluminium preferred. Iron and steel Many metals in the presence of are satisfactory. Brass, though moist gas tarnished, is acceptable Isobutane F Most common metals Isobutylene F Most common metals Krypton Most common metals Methane F Most common metals Methyl acetylene F Most common metals Copper, silver, mercury and their alloys Methylamine C F T Iron and steel Copper, tin, zinc and their alloys. Avoid mercury Methyl bromide C F T Most common metals when dry Aluminium and its alloys 3-Methyl-1-butane F Most common metals Methyl chloride F T Most common metals when Zinc, magnesium rubber and dry neoprene particularly when moist. Aluminium is forbidden Methyl fluoride F T Most common metals Methyl mercaptan F T Stainless steel and copper-free steel alloys and aluminium. Iron and steel for dry gas Methyl vinyl ether F Most common metals Copper and its alloys Neon Most common metals Nickel carbonyl F T Most common metals for pure gas. Copper or glass-lined equipment for carbonyl in the presence of carbon monoxide Nitric oxide T O Most common metals for dry gas. For moist gas use 18:8 stainless steel, PTFE Nitrogen Any common metal Nitrogen dioxide C T O Most common metals for dry gas. For moist gas use 18:8 stainless steel Nitrogen trifluoride T O Nickel and Monel are Plastics preferred. Steel, copper and glass are acceptable at ordinary temperatures Nitrogen trioxide C T O Steel for dry gas otherwise use 18:8 stainless steel Nitrosyl chloride C T O Nickel, Monel and Inconel. For moist gas tantalum is suitable Nitrous oxide O Most common metals Octofluorocyclobutane T Cast iron and stainless steel <120°C, Avoid the metals opposite steel ≤175°C, Inconel, nickel >500°C and platinum ≤400°C Oxygen O Most common metals On grease or combustible COMPRESSED GASES 269 Table 9.1 Cont’d Gas Hazard (1) Materials of construction for ancillary services (2) Compatible Incompatible 270 COMPRESSED GASES Oxygen difluoride T O Glass, stainless steel, copper, materials Monel or nickel ≤200°C. At higher temperatures only nickel and Monel are recommended Ozone F T O Glass, stainless steel, Teflon, Copper and its alloys, rubber or Hypalon, aluminium, any composition thereof, oil, Tygon, PVC and polythene grease or readily combustible material Perchloryl fluoride T Most metals and glass for dry Many gasket materials are gas at ordinary embrittled temperatures At higher temperatures many organic materials and some metals can be ignited Some metals such as titanium show deflagration in contact with the gas under severe shock Perfluorobutane Most common materials Perfluorobutene T Most common materials when dry Perfluoropropane Most common metals Phosgene C T Common metals for dry gas. Monel, tantalum or glass lined equipment for moist gas Phosphine F T Iron or steel Phosphorus pentafluoride F T Steel, nickel, Monel and Pyrex for dry gas. For moist gas hard rubber and paraffin wax Phosphorus trifluoride Steel, nickel, Monel and the more noble metals and Pyrex for dry gas Propane F Most common metals Propylene F Most common metals Propylene oxide F T Steel or stainless steel Rubber preferred though copper and brass are suitable for acetylene-free gas. PTFE gaskets Silane F T Iron, steel, copper, brass Silicone tetrafluoride C T Most common metals for the dry gas. Steel, Monel and copper for moist gas Sulphur dioxide C T O Most common metals for dry gas. Zinc Lead, carbon, aluminium and stainless steel for moist gas Sulphur hexafluoride Most common metals. Copper, stainless steel and aluminium are resistant to the decomposition products at 150°C Sulphur tetrafluoride C T Stainless steel or ‘Hastelloy Glass for moist gas C’ lined containers. Glass suitable for short exposures if dry. ‘Tygon’ for low-pressure connections Sulphuryl fluoride T Any common metal at normal Some metals at elevated temperatures and pressures temperatures Tetrafluoroethylene F Most common metals Table 9.1 Cont’d Gas Hazard (1) Materials of construction for ancillary services (2) Compatible Incompatible Tetrafluorohydrazine T O Glass, stainless steel, copper or nickel to temperatures of 200°C. For higher temperatures use nickel and Monel Trichlorofluoromethane T Steel, cast iron, brass, Some of the opposite at high copper, tin, lead, temperatures magnesium aluminium under normal, alloys and aluminium coating dry conditions >2% magnesium. Natural rubber 1,1,2-Trichloro-1,2,2- As above As above trifluoroethane Trimethylamine C F T Iron, steel, stainless steel and Copper, tin, zinc and most of Monel. Rigid steel piping their alloys Vinyl bromide F T Steel Copper and its alloys Vinyl chloride C F T Steel Copper and its alloys Vinyl fluoride F Steel Copper and its alloys Xenon Most common materials C Corrosive F Flammable T Toxic O Oxidizing (1) Even non-toxic gases are potentially hazardous owing to asphyxiation (oxygen deficiency). Irrespective of material, all equipment must be adequately designed to withstand process pressures. (2) This is a guide and is no substitute for detailed literature. To prevent interchange of fittings between cylinders of combustible and non-combustible gases, the valve outlets are screwed left-hand and right-hand thread, respectively (Table 9.2). Primary identification is by means of labelling with the name and chemical formula on the shoulder of the cylinder. Secondary identification is by use of ground colours on the cylinder body. Unless specified in Table 9.2, gas and gas mixtures shall be identified by a colour classification indicating gas properties in accordance with the risk diamond on the cylinder label e.g. Toxic and/or corrosive Yellow Flammable Red Oxidizing Light blue Inert (non-toxic, non-corrosive, Bright green non-flammable, non-oxidizing The full scheme is given in BS EN 1089–3: 1997. This should be consulted for the colour coding of gas mixtures used for inhalation e.g. medical and breathing apparatus mixtures containing oxygen. COMPRESSED GASES 271 Table 9.1 Cont’d Gas Hazard (1) Materials of construction for ancillary services (2) Compatible Incompatible Table 9.2 Specific colour codes for selected compressed gases Gas Colour Acetylene Maroon Argon Dark green Carbon dioxide Grey Helium Brown Oxygen White Nitrogen Black Nitrous oxide Blue 272 COMPRESSED GASES Table 9.3 General precautions for handling compressed gases Consult the supplier for data on the specification, properties, handling advice and on suitable service materials for individual gases. Storage Segregate according to hazard. Stores should be adequately ventilated and, ideally, located outside and protected from the weather. Store away from sources of heat and ignition. Cylinders within workplaces should be restricted to those gases in use. Specially designed compartments with partitions may be required to protect people in the event of explosion. Take into account emergency exits, steam or hot water systems, the proximity of other processes etc. Consider the possibility of dense gases accumulating in drains, basements, cable ducts, lift shafts etc. Where necessary, provide fireproof partitions/barriers to separate/protect cylinders. Protect from mechanical damage. All cylinders must be properly labelled and colour coded (BS 349). Store full and empty cylinders separately. Use in rotation: first in, first out. Restrict access to the stores to authorized staff. Display ‘No smoking’ and other relevant warning signs. Ensure that all staff are fully conversant with the correct procedures when using pressure regulators. (For cylinders without handwheel valves, the correct cylinder valve keys should be kept readily available, e.g. on the valve. Only use such keys. Do not extend handles or keys to permit greater leverage; do not use excessive force, e.g. hammering, when opening/ closing valves or connecting/disconnecting fittings. The pressure regulator must be fully closed before opening the cylinder valve. This valve can then be opened slowly until the regulator gauge indicates the cylinder pressure but should not be opened wider than necessary. The pressure regulator can then be opened to give the required delivery pressure. When a cylinder is not in use, or is being moved, the cylinder valve must be shut. When a cylinder has been connected, the valve should be opened with the regulator closed; joints should then be tested with soap/detergent solution.) Clearly and permanently mark pressure gauges for use on oxygen. Do not contaminate them with oil or grease or use them for other duties. Cylinders that cannot be properly identified should not be used; do not rely on colour code alone. Never try to refill cylinders. Never use compressed gas to blow away dust or dirt. Provide permanent brazed or welded pipelines from the cylinders to near the points of gas use. Select pipe materials suitable for the gas and its application. Any flexible piping used should be protected against physical damage. Never use rubber or plastic connections from cylinders containing toxic gases. On acetylene service, use only approved fittings and regulators. Avoid any possibility of it coming into contact with copper, copper-rich alloys or silver-rich alloys. (In the UK use at a pressure greater than 600 mbar g must be notified to HM Explosives Inspectorate for advice on appropriate standards.) On carbon dioxide service, rapid withdrawal of gas may result in plugging by solid CO 2 . Close the valve, if possible, to allow the metal to warm up; this will prevent a sudden gas discharge. Replace the correct caps or guards on cylinder valves when not in use and for return to the supplier. Test and inspect cylinders and pressure regulators regularly in accordance with current legislation. Design and manage cylinder stores in accordance with suppliers’ recommendations. Wear appropriate personal protection when entering any store. Inspect condition of cylinders regularly, especially those containing hazardous gases (e.g. corrosive). Use Transport gases in specially designed trolleys and use eye protection, stout gloves (preferably textile or leather) and protective footwear. Do not roll or drop cylinders off the backs of wagons; never lift cylinders by the cap. Ideally, depending on the length of pipe run, locate cylinders outside (for hazardous gases, valves installed within the workplace can be used for remote control of the main supply from the cylinder in the event of an emergency). Site cylinders so that they cannot become part of an electrical circuit. Securely clamp, or otherwise firmly hold in position, cylinders on installation. (Unless otherwise specified, cylinders containing liquefied or dissolved gases must be used upright.) Avoid subjecting cylinders containing liquid to excessive heat. Table 9.3 provides general guidance for handling compressed gases. The hazards and safety precautions for selected common compressed gases are discussed below to illustrate the general approach. More details should be sought from suppliers. Some methods for their preparation in situ are noted; full experimental details must be obtained from the literature. Acetylene Acetylene is manufactured by the controlled reaction between water and calcium carbide: CaC 2 + 2H 2 O → Ca (OH) 2 + C 2 H 2 Alternatively it is obtained from cracking low molecular-weight aliphatic hydrocarbons, or by the partial oxidation of natural gas. Because of its high chemical reactivity, acetylene has found wide use in synthesis of vinyl chloride, vinyl acetate, acrylonitrile, vinyl ethers, vinyl acetylene, trichloro- and tetrachloro- ethylene etc., in oxyacetylene cutting and welding, and as a fuel for atomic absorption instruments. Acetylene is a simple asphyxiant and anaesthetic. Pure acetylene is a colourless, highly flammable gas with an ethereal odour. Material of commercial purity has an odour of garlic due to the presence of impurities such as phosphine. Its physical properties are shown in Table 9.4. Acetylene, which condenses to a white solid subliming at –83 o C, is soluble in its own volume of water but highly soluble in acetone. Under certain conditions acetylene can explode when mixed with air, hydrogen or ethylene. Accidental heating of a small area of cylinder wall to 185 o C or above may promote an extremely dangerous condition. Violent reactions have occurred between acetylene and oxidants such as oxides of nitrogen (see later), nitric acid, calcium hypochlorite, ozone and halogens. In the free state acetylene can decompose violently, e.g. above 9 psig (0.62 bar) undissolved (free) acetylene will begin to dissociate and revert to its constituent elements. This is an exothermic process which can result in explosions of great violence. For this reason acetylene is transported in acetone contained in a porous material inside the cylinder. Voids in the porous substance can result from settling, e.g. if the cylinder is stored horizontally or through damage to the cylinder in the form of denting. Voids may enable acetylene to decompose, e.g. on initiation by mechanical shock if the cylinder is dropped. Fit approved cylinder pressure regulators, selected to give a maximum pressure on the reduced side commensurate with the required delivery pressure. (The regulator and all fittings upstream of it must be able to withstand at least the maximum cylinder pressure.) Fit in-line flame arresters for flammable gases and eliminate ignition sources. Use compatible pipe fittings. (Flammable gas cylinders have valves with left-hand threads; cylinders for oxygen and non- flammable gases, except occasionally helium, have valves with right-hand threads. Certain liquefied gas cylinders have two supply lines, one for gas and one for liquid, dependent on cylinder position.) Do not use oil, grease or joining compounds on any fittings for compressed gas cylinders. Fit an excess flow valve to the outlet of a regulator, selected to allow the maximum required gas flow. Use respirators and face protection etc. when changing regulators on cylinders of toxic gases. Turn off gas supply at the cylinder at the end of each day’s use. Consider the need for gas detection/alarms, e.g. for hazardous gases left in use out of normal hours. Periodic checks: Ensure no gas discharge when gauge reading is zero Ensure reading on gauge does not increase as the regulator valve is closed Check for ‘crawl’ due to wear on the regulator valve and seat assembly Ensure no leak between cylinder and regulator Overhaul regulators on a 3–6 month basis for corrosive gases, annually for others Train staff in hazards and correct handling procedures. ACETYLENE 273 Table 9.3 Cont’d 274 COMPRESSED GASES Table 9.4 Physical properties of acetylene Molecular weight 26.038 Vapour pressure of pure liquid at 21°C (not cylinder pressure) 43.8 bar Specific volume at 15.6°C, 1 atm 902.9 ml/g Boiling point at 1.22 atm –75°C Sublimation point at 1 atm –84.0°C Triple point at saturation pressure –80.8°C Specific gravity, gas at 15.6°C, 1 atm (air = 1) 0.9057 Density, gas at 0°C, 1 atm 1.1709 g/l Critical temperature 36.3°C Critical pressure 62.4 bar Critical density 0.231 g/ml Latent heat of sublimation at –84°C 193.46 cal/g Latent heat of fusion at triple point 23.04 cal/g Flammable limits in air 2.5–81.0% by volume Auto-ignition temperature 335°C Gross heat of combustion at 15.6°C, 1 atm 13.2 cal/cc Specific heat, gas at 25°C, 1 atm C p 0.4047 cal/g°C C v 0.3212 cal/g °C ratio C p / C v 1.26 Thermal conductivity, gas at 0°C 4.8 × 10 –5 cal/s cm 2 °C/cm Viscosity, gas at 25°C, 1 atm 0.00943 cP Entropy, gas at 25°C, 1 atm 1.843 cal/g °C Solubility in water at 0°C, 1 atm 1.7 vol/vol H 2 O Figure 9.1 illustrates the rise in cylinder pressure with temperature. Normally, acetylene cylinders are fitted with a fusible metal plug which melts at about 100°C. Acetylene can form metal acetylides, such as copper or silver acetylide, which on drying become highly explosive: service materials require careful selection. In addition to the general precautions for compressed gases in Table 9.3, the following control measures should be considered for acetylene: • Never use free acetylene at pressures above 9 psig (0.62 bar) unless special safety features are employed. • Store and use cylinders only in an upright position. • Store reserves separate from oxygen cylinders. • Ensure that no means of accidental ignition are in the area and provide adequate ventilation. • Consult local regulations for use of this gas. • Ensure that ‘empty’ cylinders have the valve closed to prevent evaporation of acetone. • Close cylinder valve before shutting off regulator, to permit gas to bleed from regulator. • When used e.g. for welding, avoid the careless use of flame which could fuse the metal safety plug in the cylinder. • In the event of fire issuing from the cylinder, close the gas supply if it is safe to do so and evacuate the area. • Consider the need for detection/alarm systems and in any event check periodically for leaks with e.g. soap solution, never with a naked flame. Air The physical properties of air are given in Table 9.5. Air is a mixture of nitrogen, oxygen, argon, 500 400 300 200 100 30 40 50 60 70 80 90 100 110 120 –1 41016212732 384349 °F °C Temperature Pressure (psia) carbon dioxide, water vapour, rare gases and trace quantities of ozone, oxides of nitrogen, acetylene, methane and other hydrocarbons. Its composition varies with altitude. Dry air is inert in its effect on metals and plastics. The hazards associated with compressed air, in addition to those associated with any pressure system (i.e. the potential for rupture of equipment or pipework), are: • From inhalation at pressures above atmospheric, used in tunnelling or diving, or from breathing apparatus or resuscitation equipment, if the pressure is too high or exposure is prolonged. This may cause symptoms from pain to dyspnoea, disorientation and unconsciousness; it may be fatal. • From particulate matter blown from orifices or surfaces, e.g. into the eyes. • From entry into any of the body orifices, which can result in serious internal damage. • From penetration of unbroken skin, or cuts. Foreign matter, e.g. grease, metal, concrete, may also be injected into subcutaneous tissues. • From whipping of an unsecured hose on rapid gas release. Figure 9.1 Acetylene (in acetone): full cylinder pressure versus temperature Table 9.5 Physical properties of air Density @ 20°C, 1 atm 0.0012046 g/l Critical temperature –140.6°C Critical pressure 546.8 psia (37.2 atm) (38.4 kg/cm 2 absolute) Critical density 0.313 g/ml Viscosity @ 0°C, 1 atm 170.9 micropoises AIR 275 276 COMPRESSED GASES The precautions include: • Prohibition on playing around with compressed air hoses, e.g. aiming directly at any individual. • Avoidance of blowing away dust or dirt from equipment, the floors, or clothing etc. (which may also produce a dust inhalation or explosion hazard). • Direction of the exhaust air from tools away from the operator. • Proper training and instruction for anyone required to use air-fed breathing apparatus. Restriction of exposures to compressed air to safe levels. Ammonia Ammonia can be made on a small scale by heating an intimate mixture of ammonium chloride and dry slaked lime in a ratio of 1:3, respectively: Ca(OH) 2 + 2NH 4 Cl → CaCl 2 + 2NH 3 + 2H 2 O Industrially, production is either from the Haber process at high pressure: N 2 + 3H 2 → 2NH 3 or the cyanamide process CaC 2 + N 2 → CaCN 2 + C CaCN 2 + 3H 2 O → 2NH 3 + CaCO 3 At room temperature and atmospheric pressure ammonia is a colourless, alkaline gas with a pungent smell. It dissolves readily in water. Physical properties are summarized in Table 9.6. The effect of temperature on vapour pressure of anhydrous ammonia is shown in Figure 9.2. Ammonia is shipped as a liquefied gas under its own vapour pressure of 114 psig (7.9 bar) at 21°C. Uses are to be found in refrigeration, fertilizer production, metal industries, the petroleum, chemical and rubber industries, domestic cleaning agents and water purification. Aqueous solutions of ammonia are common alkaline laboratory reagents; ca 0.88 solution is the strongest available. Ammonia gas is expelled on warming. Ammonia gas is irritating to the eyes, mucous membranes and respiratory tract. Because of its odour few individuals are likely to be unwittingly over-exposed for prolonged periods. Table 9.7 summarizes the physiological effects of human exposure. Clearly at high concentrations the gas becomes corrosive and capable of causing extensive injuries. Thus 1% in air is mildly irritating, 2% has a more pronounced effect and 3% produces stinging sensations. On contact with the skin, liquid ammonia produces severe burns compounded by frostbite due to the freezing effect from rapid evaporation from the skin. Moist ammonia attacks copper, tin, zinc and their alloys. Ammonia is also flammable with flammability limits of 15–28%. Ammonia can also react violently with a large selection of chemicals including ethylene oxide, halogens, heavy metals, and oxidants such as chromium trioxide, dichlorine oxide, dinitrogen tetroxide, hydrogen peroxide, nitric acid, liquid oxygen, and potassium chlorate. Besides the control measures given in Table 9.3, the following precautions are appropriate: • Wear rubber gloves, chemical goggles and, depending upon scale, a rubber apron or full chemical suit. • Never heat ammonia cylinders directly with steam or flames to speed up gas discharge. • Use under well-ventilated conditions and provide convenient safety showers and eye-wash facilities. • Ensure that gas cannot be accidentally ignited. • Check for leaks, e.g. with moist litmus paper or concentrated hydrochloric acid (which forms dense white fumes of ammonium chloride). • In the event of accident, administer first aid (see Table 9.9). Carbon dioxide Carbon dioxide is present in air and is a constituent of natural gas escaping from mineral springs and fissures in the earth’s surface. It is also the ultimate product of combustion of carbon and its compounds. Laboratory scale preparation usually entails reaction between dilute hydrochloric acid and marble (calcium carbonate): 2HCl + CaCO 3 → CaCl 2 + H 2 O + CO 2 Industrially, it is obtained as a by-product of fermentation of sugar to alcohol: C 6 H 12 O 2 → 2C 2 H 5 OH + 2CO 2 or by burning coke/limestone mixture in a kiln: CaCO 3 → CO 2 + CaO Table 9.6 Physical properties of ammonia Molecular weight 17.031 Vapour pressure at 21°C (cylinder pressure) 7.87 bar Specific volume at 21°C, 1 atm 1.411 ml/g Boiling point at 1 atm – 33.35°C Triple point at 1 atm – 77.7°C Triple point pressure 1.33 mbar Specific gravity, gas at 0°C, 1 atm (air = 1) 0.5970 Density, gas at boiling point 0.000 89 g/ml Density, liquid at boiling point 0.674 g/ml Critical temperature 132.44°C Critical pressure 113 bar Critical density 0.235 g/ml Flammable limits in air 15–28% by volume Latent heat of vaporization at boiling point 327.4 cal/g Specific heat, liquid at –20°C 1.126 cal/g K Specific heat, gas at 25°C, 1 atm C p 0.5160 cal/g°C C v 0.4065 cal/g °C ratio, C p / C v 1.269 Thermal conductivity, gas at 25°C, 1 atm 5.22 × 10 –5 cal/s cm 2 °C/cm Entropy, gas at 25°C, 1 atm 2.7 cal/g °C Heat of formation, gas at 25°C –648.3 cal/g Solubility at 0°C, 1 atm in water 42.8% by weight in methanol, absolute 29.3% by weight in ethanol, absolute 20. 95% by weight Viscosity, gas at 0°C, 1 atm 0.009 18 cP Viscosity, liquid at –33.5°C 0.266 cP CARBON DIOXIDE 277 278 COMPRESSED GASES Boiling point 2252001751501251007550250–25–50–75–100°F 10793796652372510–4–18–32–46–60–73°C Temperature 1000 900 800 700 600 500 400 300 200 100 90 70 60 50 40 30 20 10 9 8 7 6 5 4 3 2 80 1 Vapour pressure (psia) Liquid carbon dioxide is discussed on page 261. Carbon dioxide gas is commonly used for carbonating drinks, in fire extinguishers, for gas-shielding of welding and in shell moulding in foundries. Its physical and toxicological properties are summarized in Tables 8.5, 8.6 and 5.29. The gas is non-flammable, and is used for inert gas purging. Because it is 1.5 times heavier than air it may accumulate at low level. The general handling precautions are those in Table 9.3. Figure 9.2 Ammonia vapour pressure versus temperature [...]... Butane 58. 1 1.15 isoButane 58. 1 21 .6 530.6 – 42. 07 – 187 .69 1.5503 0.5505 (20 °C) 2. 02 96 .8 42 0 .22 0 101.76 19.10 – 399.5 –0.5 –1 38. 3 2. 076 0.5 788 (20 °C) 2. 70 1 52 37.5 0 .22 5 92. 0 19.17 0.5636 405 .8 –11.73 –159.6 2. 01 0.563 (15°C) – 135 37 .2 0 .22 1 87 .56 18. 67 0.5695 0. 388 5 0.3434 1.13 1.131 22 .8 0.39 08 0.3566 1.1 1.096 30.0 0. 38 72 0.3530 1.1 1.097 29 .8 0.0 080 3 (16°C) 0.0016 0.0 084 (15°C) 0.0011 0.00755 (23 °C)... event of exposure, apply first aid as in Table 9.9 (refer also to Table 13.17)  28 2 COMPRESSED GASES 1000 900 Critical pressure 11 18. 7 psia at 144°C 80 0 700 600 500 400 300 Vapour pressure (psia) 20 0 100 90 80 70 60 50 40 30 20 Boiling point °F 10 –50 25 0 25 50 75 100 125 150 175 20 0 22 5 25 0 27 5 °C –46 – 32 – 18 –4 10 25 37 52 66 79 93 107 107 135 Temperature Figure 9.3 Chlorine vapour pressure versus... 0.3566 1.1 1.096 30.0 0. 38 72 0.3530 1.1 1.097 29 .8 0.0 080 3 (16°C) 0.0016 0.0 084 (15°C) 0.0011 0.00755 (23 °C) – 16.49 (–50°C) 6.5 ( 18 C) 2. 2–9.5 467 .8 0 .86 0 .25 21 55 0.45 16. 02 (–10°C) – – 1.9 8. 5 405 0 .86 0 .25 21 30 0. 38 15 . 28 ( 20 °C) 1.7 (17°C) 1 .8 8. 4 543 – – – – 45 32 41 29 – – from an appliance in which the flame has been extinguished Any fire near an LPG cylinder may cause it to overheat and catch... Cp /Cv Thermal conductivity, gas at 0°C Viscosity, gas at 20 °C, 1 atm Viscosity, liquid at 20 °C Solubility in water at 20 °C, 1 atm 70.906 5 .88 bar 337.1 ml/g –34.05°C –100. 98 C 2. 49 1.41 3 .21 4 g/l 1.4 68 g/l 144°C 77.1 bar 0.573 g/ml 68. 8 cal/g 22 .9 cal/g 0 .22 6 cal/g °C 0.115 cal/g °C 0. 085 cal/g °C 1.355 1 .8 × 10–5 cal/s cm2 °C/cm 0.0147 cP 0. 325 cP 7.30 g/l The following safety measures supplement the... Specific heat, gas at 0 20 0°C, 1 atm Cp Cv ratio Cp/Cv Thermal conductivity at 0°C Viscosity, gas at 15°C, 1 atm Solubility in water at 15.6°C, 1 atm 2. 016 11 967 ml/g 25 2.9°C 25 9.3°C 0.069 52 0. 089 9 g/l 0.07 08 g/ml 24 0 .2 C 12. 98 bar 0.03136 g/ml 106.5 cal/g 13 .87 5 cal/g 4.0–75% by volume 585 °C 3.44 cal/g °C 2. 46 cal/g °C 1.40 0.00040 cal/s cm2 °C/cm 0.0 087 cP 0.019 vol/vol H2O The main danger with... its own vapour pressure of ca 109 psig at 21 °C Its pressure/temperature profile is given in Figure 9.7  28 8 COMPRESSED GASES 1000 900 80 0 700 Critical pressure 1309 psia at 100.4°C 600 500 400 300 Vapour pressure (psia) 20 0 100 90 80 70 60 50 40 30 20 Boiling point °F 10 –100 –75 –50 25 0 25 50 75 100 125 150 175 20 0 22 5 °C –73 –60 –46 – 32 – 18 –4 10 25 37 52 66 79 93 107 Temperature Figure 9.5 Hydrogen... Viscosity (gas) @ 0°C, 1 atm Entropy (gas) @ 25 °C Heat of formation (gas) @ 25 °C 28 .01 13 .8 cu.ft/lb (86 1.5 ml/g) –191.5°C 20 5.01°C 115.14 mm Hg 0.96 78 1444 cal/mole 20 0.9 cal/mole 12. 5–74% 650°C 0 .24 91 cal/g °C 0.1774 cal/g °C 1.4 0.0166 centipoise 47 .26 6 cal/mole °C 26 .417 kcal/mole 28 0 COMPRESSED GASES CO + Cl2 → COCl2 Liquid carbon monoxide in the presence of nitrous oxide poses blast hazards... Viscosity (gas) @ 1 atm, 4.4°C 16.04 1479.5 ml/g –161.5oC –1 82 . 6°C –1 82 . 5°C 0.115 atm 0.5549 0. 72 g/l 0. 425 6 g/l – 82 . 1°C 673.3 psia (45 .8 atm) 0.1 62 g/ml 121 .54 cal/g 1.307 5.3–14% 540°C 0 . 28 mJ 188 0°C 11.5% 0.0106 cP Since it is chemically inert no special materials of construction are required Selected physical properties are listed in Table 9 .20 Nitrogen is non-toxic but will cause asphyxiation through... 30.006 81 1 ml/g –151.7°C –163.6°C 1.34 02 g/l 1 .26 9 g/l –93°C 940 .8 psia (64 atm) 0. 52 g/ml 110 .2 cal/g 0 .23 28 cal/g °C 0.1664 cal/g °C 1.4 0.01 78 cP 7.34 ml/100 g water Nitric oxide combines readily with atmospheric oxygen at ambient temperature to produce brown fumes of pungent nitrogen dioxide, and in the presence of charcoal with chlorine to form nitrosyl chloride: 2NO + O2 → NO2 2NO + Cl2 → 2NOCl... ml/g 89 .5°C –90 .84 °C 1.530 1.907 g/l 1 .26 6 g/l 36.5°C 1054 psia (71.7 atm) 0.457 g/l 89 .9 cal/g 0 .20 98 cal/g °C 0.1610 cal/g °C 1.3 0.013 62 centipoise 1.3 volumes/volume of water NITROGEN OXIDES 29 7 1300 Vapour pressure (psia) 1000 500 100 °F °C 80 – 62 –60 –51 0 – 18 60 16 100 38 Temperature Figure 9.9 Nitrous oxide vapour pressure vs temperature properties of nitric oxide are given in Table 9 .22 This . 1 .8 × 10 –5 cal/s cm 2 °C/cm Viscosity, gas at 20 °C, 1 atm 0.0147 cP Viscosity, liquid at 20 °C 0. 325 cP Solubility in water at 20 °C, 1 atm 7.30 g/l CHLORINE 28 1 28 2 COMPRESSED GASES 27 525 022 520 0175150 125 100755 025 0 25 –50°F 135107107937966 523 725 10–4– 18 32 46°C Temperature 1000 900 700 600 500 400 300 20 0 100 90 70 80 0 40 80 60 50 30 20 10 Critical pressure 11 18. 7. GASES 27 525 022 520 0175150 125 100755 025 0 25 –50°F 135107107937966 523 725 10–4– 18 32 46°C Temperature 1000 900 700 600 500 400 300 20 0 100 90 70 80 0 40 80 60 50 30 20 10 Critical pressure 11 18. 7 psia at. COMPRESSED GASES 1000 900 80 0 700 600 500 400 300 20 0 100 90 80 70 60 50 40 30 20 10 22 520 0175150 125 100755 025 0 25 –50°F 107937966 523 725 10–4– 18 32 46°C Temperature –75 –60 –100 –73 Vapour pressure