Carbon dioxide - SIAD Società Italiana Acetilene e Derivati
Carbon dioxide header
Carbon dioxide is an integral part of the basic life cycle in nature: it is exhaled by humans and animals, then used by plants to help them grow; plants, in turn, release oxygen, which people depend on for survival.
Product: carbon dioxide
Chemical formula: CO2
Purity level: ≥ 99.5%
Relative density (air = 1): 1.529
Aspect: colourless gas
Odour: odourless gas
Limit of flammability in air: non infiammabile
Carbon dioxide is used in several applications, which are listed below.
Food and beverage industry
In the food and beverage industry, carbon dioxide is used:
- for beverage carbonation
- as a natural anti-bacterial, to increase the shelf life of dairy products, protecting taste and texture, and reducing the need for both natural and artificial preservatives
- for food freezing and chilling
- for cryogenic and IQF freezing of foodstuffs
- for modified atmosphere packaging
- for mixer and blender cooling
- for ingredient cooling and conveying
- for in-transit refrigeration
- for cryo-blasting of food dyes and production plants
- in its solid form, known as dry ice.
Water treatment industry
In the water treatment industry, carbon dioxide is used:
- for the neutralisation processes. Carbon dioxide replaces harsher acids for the alkaline neutralisation process. It is safer and cheaper than sulphuric-acid systems, improves control, and there is less downtime and no labour to handle chemicals. It is also less corrosive, and easier to handle and store.
In metal fabrication, carbon dioxide is used:
- as a shielding gas during welding. It prevents atmospheric contamination of molten weld metal during the gas shielded electric arc welding process.
In nurseries, carbon dioxide is used:
- for plant growth. Carbon dioxide systems greatly improve growth and quality of plants in the greenhouse. Increasing concentrations of the gas results in larger, healthier and faster-growing plants and lower operating costs, especially during the winter, when it can reduce heating costs by 50%. Carbon dioxide replaces gas generators, saving fuel costs and eliminating harmful emissions.
Pulp and paper industry
In the pulp and paper industry, carbon dioxide is used:
- for several different applications within paper mills, all developed to reduce costs and recover valuable chemicals used within the mill process. A process using carbon dioxide, instead of sulphuric acid, to treat pitch build-up in screen rooms is proving very successful.
- to make precipitated calcium carbonate (PCC), which is used to reduce the use of virgin wood fiber in paper making.
Other important applications of carbon dioxide are:
- as an energy source. Storage of carbon dioxide at its triple point (the temperature-pressure combination at which carbon dioxide can exist simultaneously as a solid, liquid or gas) is being tested as a means of providing closed-loop refrigeration in order to shift electrical-energy demand to off-peak consumption hours
- in cleaning and solvent extraction, in its supercritical state (87.9°F (31.1°C) and 1070.6 psia (7.38MPa)), to replace chlorinated fluorocarbons to clean equipment components
- in cleaning and solvent extraction, in its supercritical state (87.9°F (31.1°C) and 1070.6 psia (7.38MPa)), to replace many volatile organic chemicals for operations such as decaffeinating coffee or extracting fat from food products
- in cryogenic cleaning. Carbon dioxide dry-ice pellets accelerated by compressed air can eliminate cleaning solvents and abrasive grit such as sand and plastic beads. This process also eliminates dust and toxic chemical vapours and minimises waste disposal. Carbon dioxide is non-conductive - safe for cleaning electrical components - and non-abrasive, non-explosive and non-flammable
- in fire fighting. Carbon dioxide smothers fires without damaging or contaminating materials and is used for fighting fires when water is ineffective, undesirable or unavailable.
To avoid harmful effects, producers and customers should follow strict safety guidelines for storage and handling, and consult our carbon dioxide Material Safety Data Sheet.
Hydrogen and carbon dioxide production is carried out through steam reforming, a process based on the reaction between methane and water vapour.
The main steps of the process are listed below:
- compression, heating at 260 °C and purification of the methane
- demineralisation, disoxygenation, pH correction and water vaporization (at 200°C)
- introduction of methane and water vapour into the reactor tubes
- reaction between methane and water vapour at 800 °C, thanks to the presence of a nickel based catalyst
CH4 + 2H2O + Q = 4H2 + CO2
- recovery of carbon dioxide contained in the raw hydrogen through absorption in extraction tower and following liquefaction
- purification and compression at 200 bar of the hydrogen produced.
The recovery and storage of carbon dioxide combines economic advantages with environmental topics, thanks to the resulting reduction of Greenhouse Effect gases emissions in the atmosphere.
Carbon dioxide supply options and services available to SIAD customers include:
- transport in cylinders, cylinder packs and tanks
- design and installation of gas distribution systems
- supply of equipment for the correct use of the gas
- assistance and technical consultancy for the transport, distribution and application of the gas.
Carbon dioxide can also be supplied:
- with grade 3.5 - 4.0 - 4.8 purity
- in special and in calibration mixtures with different composition upon request
- in mixtures for laser
- for therapeutic and diagnostic use.