Dry ice colloquially means the solid form of carbon dioxide. It is commonly used for temporary refrigeration as CO2 does not have a liquid state at normal atmospheric pressure and sublimes directly from the solid state to the gas state. It is used primarily as a cooling agent, but is also used in fog machines at theatres for dramatic effects. Its advantages include lower temperature than that of water ice and not leaving any residue (other than incidental frost from moisture in the atmosphere). It is useful for preserving frozen foods (such as ice cream) where mechanical cooling is unavailable.
Dry ice sublimes at 194.7 K (−78.5 °C; −109.2 °F) at Earth atmospheric pressure. This extreme cold makes the solid dangerous to handle without protection from frostbite injury. While generally not very toxic, the outgassing from it can cause hypercapnia (abnormally elevated carbon dioxide levels in the blood) due to buildup in confined locations.
Dry ice is the solid form of carbon dioxide (CO2), a molecule consisting of a single carbon atom bonded to two oxygen atoms. Dry ice is colorless, odorless, and non-flammable, and can lower the pH of a solution when dissolved in water, forming carbonic acid (H2CO3). [1]
At pressures below 5.13 atm and temperatures below−56.4 °C (216.8 K; −69.5 °F) (the triple point), CO2 changes from a solid to a gas with no intervening liquid form, through a process called sublimation. [lower-alpha 1] The opposite process is called deposition, where CO2 changes from the gas to solid phase (dry ice). At atmospheric pressure, sublimation/deposition occurs at 194.7 K (−78.5 °C; −109.2 °F). [2]
The density of dry ice increases with decreasing temperature and ranges between about 1.55 and 1.7 g/cm3 (97 and 106 lb/cu ft) below 195 K (−78 °C; −109 °F). [3] The low temperature and direct sublimation to a gas makes dry ice an effective coolant, since it is colder than water ice and leaves no residue as it changes state. [4] Its enthalpy of sublimation is 571 kJ/kg (25.2 kJ/mol, 136.5 calorie/g).
Dry ice is non-polar, with a dipole moment of zero, so attractive intermolecular van der Waals forces operate. [5] The composition results in low thermal and electrical conductivity. [6]
It is generally accepted that dry ice was first observed in 1835 by French inventor Adrien-Jean-Pierre Thilorier (1790–1844), who published the first account of the substance. [7] [8] In his experiments, it was noted that when opening the lid of a large cylinder containing liquid carbon dioxide, most of the liquid carbon dioxide quickly evaporated. This left only solid dry ice in the container. In 1924, Thomas B. Slate applied for a US patent to sell dry ice commercially. Subsequently, he became the first to make dry ice successful as an industry. [9] In 1925, this solid form of CO2 was trademarked by the DryIce Corporation of America as "Dry ice", leading to its common name. [10] That same year the DryIce Co. sold the substance commercially for the first time, marketing it for refrigeration purposes. [9]
Dry ice is easily manufactured. [11] [12] The most common industrial method of manufacturing dry ice starts with a gas having a high concentration of carbon dioxide. Such gases can be a byproduct of another process, such as producing ammonia from nitrogen and natural gas, oil refinery activities or large-scale fermentation. [12] Second, the carbon dioxide-rich gas is pressurized and refrigerated until it liquefies. Next, the pressure is reduced. When this occurs some liquid carbon dioxide vaporizes, causing a rapid lowering of temperature of the remaining liquid. As a result, the extreme cold causes the liquid to solidify into a snow-like consistency. Finally, the snow-like solid carbon dioxide is compressed into small pellets or larger blocks of dry ice. [13] [14]
Dry ice is typically produced in three standard forms: large blocks, small (1⁄2 or 5⁄8 in [13 or 16 mm] diameter) cylindrical pellets and tiny (1⁄8 inch [3.2 mm] diameter) cylindrical, high surface to volume pellets that float on oil or water and do not stick to skin because of their high radii of curvature. Tiny dry ice pellets are used primarily for dry ice blasting, quick freezing, fire fighting, oil solidifying and have been found to be safe for experimentation by middle school students wearing appropriate personal protective equipment such as gloves and safety glasses. A standard block weighing approximately 30 kg (66 lb)[ citation needed ] covered in a taped paper wrapping is most common. These are commonly used in shipping, because they sublime relatively slowly due to a low ratio of surface area to volume. Pellets are around 1 cm (0.4 in) in diameter and can be bagged easily. This form is suited to small scale use, for example at grocery stores and laboratories where it is stored in a thickly insulated chest. [15] Density of pellets is 60–70% of the density of blocks. [16]
Dry ice is also produced as a byproduct of cryogenic air separation, an industry primarily concerned with manufacturing extremely cold liquids such as liquid nitrogen and liquid oxygen. In this process, carbon dioxide liquefies or freezes at a far higher temperature compared to that needed to liquefy nitrogen and oxygen. The carbon dioxide must be removed during the process to prevent dry ice from fouling the equipment, and once separated can be processed into commercial dry ice in a manner similar to that described above.
The most common use of dry ice is to preserve food, [1] using non-cyclic refrigeration.
It is frequently used to package items that must remain cold or frozen, such as ice cream or biological samples, in the absence of availability or practicality of mechanical cooling.
Dry ice is critical in the deployment of some vaccines, which require storage at ultra-cold temperatures along their supply line. [17]
Dry ice can be used to flash-freeze food [18] or laboratory biological samples, [19] carbonate beverages, [18] make ice cream, [20] solidify oil spills [21] and stop ice sculptures and ice walls from melting.
Dry ice can be used to arrest and prevent insect activity in closed containers of grains and grain products, as it displaces oxygen, but does not alter the taste or quality of foods. For the same reason, it can prevent or retard food oils and fats from becoming rancid.
When dry ice is placed in water, sublimation is accelerated, and low-sinking, dense clouds of smoke-like fog are created. This is used in fog machines, at theatres, haunted house attractions, and nightclubs for dramatic effects. Unlike most artificial fog machines, in which fog rises like smoke, fog from dry ice hovers near the ground. [14] Dry ice is useful in theatre productions that require dense fog effects. [22] The fog originates from the bulk water into which the dry ice is placed, and not from atmospheric water vapor (as is commonly assumed). [23]
It is occasionally used to freeze and remove warts. [24] However, liquid nitrogen performs better in this role, as it is colder, thereby requiring less time to act, and needs less pressure to store. [25] Dry ice has fewer problems with storage, since it can be generated from compressed carbon dioxide gas as needed. [25]
In plumbing, dry ice is used to cut off water flow to pipes to allow repairs to be made without shutting off water mains. Pressurised liquid CO2 is forced into a jacket wrapped around a pipe, which in turn causes the water inside to freeze and block the pipe. When the repairs are done, the jacket is removed and the ice plug melts, allowing the flow to resume. This technique can be used on pipes up to 4 inches or 100 mm in diameter. [26]
Dry ice can be used as bait to trap mosquitoes, bedbugs, and other insects, due to their attraction to carbon dioxide. [27]
It can be used to exterminate rodents. This is done by dropping pellets into rodent tunnels in the ground and then sealing off the entrance, thus suffocating the animals as the dry ice sublimates. [28]
Tiny dry ice pellets can be used to fight fire by both cooling fuel and suffocating the fire by excluding oxygen. [29]
The extreme temperature of dry ice can cause viscoelastic materials to change to glass phase. Thus, it is useful for removing many types of pressure sensitive adhesives.
Dry ice can be used for loosening asphalt floor tiles or car sound deadening material, making them easy to prise off, [30] as well as freezing water in valveless pipes to enable repair. [31]
One of the largest mechanical uses of dry ice is blast cleaning. Dry ice pellets are shot from a nozzle with compressed air, combining the power of the speed of the pellets with the action of the sublimation. This can remove residues from industrial equipment. Examples of materials removed include ink, glue, oil, paint, mold and rubber. Dry ice blasting can replace sandblasting, steam blasting, water blasting or solvent blasting. The primary environmental residue of dry ice blasting is the sublimed CO2, thus making it a useful technique where residues from other blasting techniques are undesirable. [32] Recently, blast cleaning has been introduced as a method of removing smoke damage from structures after fires.
Dry ice is also useful for the de-gassing of flammable vapours from storage tanks — the sublimation of dry ice pellets inside an emptied and vented tank causes an outrush of CO2 that carries with it the flammable vapours. [33]
The removal and fitting of cylinder liners in large engines requires the use of dry ice to chill and thus shrink the liner so that it freely slides into the engine block. When the liner then warms up, it expands, and the resulting interference fit holds it tightly in place. Similar procedures may be used in fabricating mechanical assemblies with a high resultant strength, replacing the need for pins, keys or welds. [34]
Dry ice has found its application in construction for freezing soil, serving as an effective alternative to liquid nitrogen [35] . This method reduces the soil temperature to approximately -70 to -74 °C, rapidly freezing the groundwater. As a result, the soil's strength and impermeability significantly increase [36] , which is essential for the safe execution of underground construction projects [37] .
It is also useful as a cutting fluid.
In laboratories, a slurry of dry ice in an organic solvent is a useful freezing mixture for cold chemical reactions and for condensing solvents in rotary evaporators. [38] Dry ice and acetone forms a cold bath of −78 °C (−108 °F; 195 K), which can be used for instance to prevent thermal runaway in a Swern oxidation.
The process of altering cloud precipitation can be done with the use of dry ice. [39] It was widely used in experiments in the US in the 1950s and early 1960s before it was replaced by silver iodide. [39] Dry ice has the advantage of being relatively cheap and completely non-toxic. [39] Its main drawback is the need to be delivered directly into the supercooled region of clouds being seeded. [39]
A "dry ice bomb" is a balloon-like device using dry ice in a sealed container such as a plastic bottle. Water is usually added to accelerate the sublimation of the dry ice. As the dry ice sublimes, pressure increases, causing the bottle to burst with a loud noise. The screw cap can be replaced with a rubber stopper to make a water rocket.
The dry ice bomb device was featured on MythBusters , episode 57 Mentos and Soda, which first aired on August 9, 2006. [40] It was also featured in an episode of Time Warp , as well as in an episode of Archer .
Following the Mars flyby of the Mariner 4 spacecraft in 1966, scientists concluded that Mars' polar caps consist entirely of dry ice. [41] However, findings made in 2003 by researchers at the California Institute of Technology have shown that Mars' polar caps are almost completely made of water ice, and that dry ice only forms a thin surface layer that thickens and thins seasonally. [41] [42] A phenomenon named dry ice storms was proposed to occur over the polar regions of Mars. They are comparable to Earth's thunderstorms, with crystalline CO2 taking the place of water in the clouds. [43] Dry ice is also proposed as a mechanism for the geysers on Mars. [44]
In 2012, the European Space Agency's Venus Express probe detected a cold layer in the atmosphere of Venus where temperatures are close to the triple point of carbon dioxide and it is possible that flakes of dry ice precipitate. [45]
Observations from the Uranus flyby by Voyager 2 indicates that dry ice is present on the surface of its large moons Ariel, [46] Umbriel [46] and Titania. [46] Scientists speculate that the magnetic field of Uranus contributes to the generation of CO2 ice on the surfaces of its moons. [47] Voyager 2 observations of Neptune's moon Triton suggested the presence of dry ice on the surface, though followup observations indicate that the carbon ices on the surface are carbon monoxide but that the moon's crust is composed of a significant quantity of dry ice. [48]
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Prolonged exposure to dry ice can cause severe skin damage through frostbite, and the fog produced may also hinder attempts to withdraw from contact in a safe manner. Because it sublimes into large quantities of carbon dioxide gas, which could pose a danger of hypercapnia, dry ice should only be exposed to open air in a well-ventilated environment. [30] For this reason, in the context of laboratory safety dry ice is assigned label precaution P403: "Store in a well ventilated place." Industrial dry ice may contain contaminants that make it unsafe for direct contact with food. [50] [ failed verification ] Tiny dry ice pellets used in dry ice blast cleaning do not contain oily residues.
Dry ice is assigned a UN number, a code for hazardous substances: UN 1845. [51] Dry ice is not classified as a dangerous substance by the European Union, or as a hazardous material by the United States Department of Transportation for ground transportation. [52] [51] However, in the US, it is regulated as a dangerous good when shipped by air or water. International Air Transport Association (IATA) regulations require specific diamond-shaped black-and white labelling to be placed on the package. The package must have adequate ventilation so that it will not rupture from pressure in the event that the Dry Ice begins to sublime in the packaging. [51] The Federal Aviation Administration in the US allows airline passengers to carry up to 2.5 kg (5.5 lb) per person either as checked baggage or carry-on baggage, when used to refrigerate perishables. [53]
At least one person has been killed by carbon dioxide gas subliming off dry ice in coolers placed in a car. [54] In 2020, three people were killed at a party in Moscow after 25 kg of dry ice was dumped in a pool; carbon dioxide is heavier than air, and so can linger near the ground, just above water level. [55]
Dry ice is sometimes used to give a fog effect to cocktails. One bar patron who accidentally ingested pellets from a drink suffered severe burns to his esophagus, stomach, and duodenum, causing permanent problems with eating. [56] [57] Rapid sublimation could cause gas buildup that ruptures digestive organs or suffocation. Products that contain dry ice and prevent it from being accidentally ingested eliminate these risks while producing the desired fog effect. [58]
Carbon dioxide is a chemical compound with the chemical formula CO2. It is made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature, and as the source of available carbon in the carbon cycle, atmospheric CO2 is the primary carbon source for life on Earth. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, and seawater. When carbon dioxide dissolves in water, it forms carbonate and mainly bicarbonate, which causes ocean acidification as atmospheric CO2 levels increase.
Water vapor, water vapour or aqueous vapor is the gaseous phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Water vapor is transparent, like most constituents of the atmosphere. Under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation. It is less dense than most of the other constituents of air and triggers convection currents that can lead to clouds and fog.
Gasification is a process that converts biomass- or fossil fuel-based carbonaceous materials into gases, including as the largest fractions: nitrogen (N2), carbon monoxide (CO), hydrogen (H2), and carbon dioxide (CO2). This is achieved by reacting the feedstock material at high temperatures (typically >700 °C), without combustion, via controlling the amount of oxygen and/or steam present in the reaction. The resulting gas mixture is called syngas (from synthesis gas) or producer gas and is itself a fuel due to the flammability of the H2 and CO of which the gas is largely composed. Power can be derived from the subsequent combustion of the resultant gas, and is considered to be a source of renewable energy if the gasified compounds were obtained from biomass feedstock.
Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the liquid state. The verb form of sublimation is sublime, or less preferably, sublimate. Sublimate also refers to the product obtained by sublimation. The point at which sublimation occurs rapidly is called critical sublimation point, or simply sublimation point. Notable examples include sublimation of dry ice at room temperature and atmospheric pressure, and that of solid iodine with heating.
A supercritical fluid (SCF) is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist, but below the pressure required to compress it into a solid. It can effuse through porous solids like a gas, overcoming the mass transfer limitations that slow liquid transport through such materials. SCFs are superior to gases in their ability to dissolve materials like liquids or solids. Also, near the critical point, small changes in pressure or temperature result in large changes in density, allowing many properties of a supercritical fluid to be "fine-tuned".
In vacuum applications, a cold trap is a device that condenses all vapors except the permanent gases into a liquid or solid. The most common objective is to prevent vapors being evacuated from an experiment from entering a vacuum pump where they would condense and contaminate it. Particularly large cold traps are necessary when removing large amounts of liquid as in freeze drying.
A fog machine, fog generator, or smoke machine is a device that emits a dense vapor that appears similar to fog or smoke. This artificial fog is most commonly used in professional entertainment applications, but smaller, more affordable fog machines are becoming common for personal use. Fog machines can also be found in use in a variety of industrial, training, and some military applications. Typically, fog is created by vaporizing proprietary water and glycol-based or glycerin-based fluids or through the atomization of mineral oil. This fluid vaporizes or atomizes inside the fog machine. Upon exiting the fog machine and mixing with cooler outside air, the vapor condenses, resulting in a thick, visible fog.
A coolant is a substance, typically liquid, that is used to reduce or regulate the temperature of a system. An ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, chemically inert and neither causes nor promotes corrosion of the cooling system. Some applications also require the coolant to be an electrical insulator.
This page provides supplementary chemical data on carbon dioxide.
Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure.
A dry ice bomb is a simple explosive device. While their simplicity, ease of construction, high bursting pressure and loud noise make them appealing for recreational purposes, they can be unpredictable and dangerous. These bombs have led to many injuries and are illegal in many jurisdictions.
Charles-Saint-Ange Thilorier was a student at the École polytechnique in the class / year of 1815, who was mistakenly believed to have been the first person to create solid carbon dioxide. Actually, a French inventor, Adrien-Jean-Pierre Thilorier (1790–1844), discovered dry ice.
Theatrical smoke and fog, also known as special effect smoke, fog or haze, is a category of atmospheric effects used in the entertainment industry. The use of fogs can be found throughout motion picture and television productions, live theatre, concerts, at nightclubs and raves, amusement and theme parks and even in video arcades and similar venues. These atmospheric effects are used for creating special effects, to make lighting and lighting effects visible, and to create a specific sense of mood or atmosphere. Recently smaller, cheaper fog machines have become available to the general public, and fog effects are becoming more common in residential applications, from small house parties to Halloween and Christmas.
Dry-ice blasting is a form of carbon dioxide cleaning, where dry ice, the solid form of carbon dioxide, is accelerated in a pressurized air stream and directed at a surface in order to clean it.
A carbon dioxide scrubber is a piece of equipment that absorbs carbon dioxide (CO2). It is used to treat exhaust gases from industrial plants or from exhaled air in life support systems such as rebreathers or in spacecraft, submersible craft or airtight chambers. Carbon dioxide scrubbers are also used in controlled atmosphere (CA) storage and carbon capture and storage processes.
The planet Mars has two permanent polar ice caps of water ice and some dry ice (frozen carbon dioxide, CO2). Above kilometer thick layers of water ice permafrost slabs of dry ice are depositioned during a pole's winter, lying in continuous darkness, causing 25–30% of the atmosphere being depositioned annually at either of the poles. When the poles are again exposed to sunlight, the frozen CO2 sublimes. These seasonal actions transport large amounts of dust and water vapor, giving rise to Earth-like frost and large cirrus clouds.
Martian gullies are small, incised networks of narrow channels and their associated downslope sediment deposits, found on the planet of Mars. They are named for their resemblance to terrestrial gullies. First discovered on images from Mars Global Surveyor, they occur on steep slopes, especially on the walls of craters. Usually, each gully has a dendritic alcove at its head, a fan-shaped apron at its base, and a single thread of incised channel linking the two, giving the whole gully an hourglass shape. They are estimated to be relatively young because they have few, if any craters. A subclass of gullies is also found cut into the faces of sand dunes, that are themselves considered to be quite young. Linear dune gullies are now considered recurrent seasonal features.
Carbon dioxide cleaning (CO2 cleaning) comprises a family of methods for parts cleaning and sterilization, using carbon dioxide in its various phases. Due to being non-destructive, non-abrasive, and residue-free, it is often preferred for use on delicate surfaces. CO2 cleaning has found application in the aerospace, automotive, electronics, medical, and other industries. Carbon dioxide snow cleaning has been used to remove particles and organic residues from metals, polymers, ceramics, glasses, and other materials, and from surfaces including hard drives and optical surfaces.
The dry ice color show is a demonstration of the chemical formation of carbonic acid by the dissolution of dry ice in water. The dry ice color show is usually performed in classrooms to demonstrate the properties of acids and bases, their effect on pH indicators, and the sublimation of dry ice. Setup is simple and generally involves only minor hazards, the main one being the low temperature of dry ice, which can cause frostbite upon skin contact. The carbonic acid formed in the demonstration is a weak acid and is not hazardous, being present in numerous consumer products including tonic water, soda, and beer.
Liquid carbon dioxide is the liquid state of carbon dioxide, which cannot occur under atmospheric pressure. It can only exist at a pressure above 5.1 atm, under 31.1 °C (88.0 °F) and above −56.6 °C (−69.9 °F). Low-temperature carbon dioxide is commercially used in its solid form, commonly known as "dry ice". Solid CO
2 sublimes at 194.65 K at Earth atmospheric pressure — that is, it transitions directly from solid to gas without an intermediate liquid stage. The uses and applications of liquid carbon dioxide include decaffeinating coffee, extracting virgin olive oil from olive paste, in fire extinguishers, and as a coolant.