Carbon dioxide gas
plants are carbon dioxide generating systems. Carbon dioxide (CO
2),
a chemical compound made up of two oxygen atoms covalently bonded to a
single carbon atom, is a slightly toxic, odorless, colorless gas, used for
various industrial purposes. CO
2 is a gas at standard
temperature and pressure. Its existence in Earth's atmosphere as a small but
important constituent of air is in the form of a gas with a slightly
pungent, acid taste. Being one of the most abundant gases in the atmosphere,
CO
2 plays a vital role in plant and animal process, like
photosynthesis and respiration. Large quantities of carbon dioxide are
produced and consumed at industrial sites making fertilizers, plastics and
rubber. Manufacturers and suppliers dealing with gas plants usually supply
complete carbon dioxide recovery, purification and liquefaction plants on a
turnkey basis or on an equipment sale.
Manufacturing Process
The combustion and biological processes including decomposition of organic
material, fermentation and digestion leads to the formation of carbon
dioxide plants. In atmosphere, it combines with water to form carbonic acid
which corrodes limestone, marble and metals. The concentration of carbon
dioxide in atmosphere is not high enough to make it commercially recoverable
as a product. Commercial production depends on separating and purifying CO
2-rich
gases which are produced by biological or combustion processes. If these
gases are not recovered, they are vented to the atmosphere. That is why in
gas plants, the commercial CO
2 is mostly recovered as by-product
of other processes.
Sources of CO2
Most gas plants produce CO
2 from the following sources:
- Steam methane and naptha reformers
- High pressure wells
- Ammonia plants
- Breweries
- Heavy fuel burning facilities
- Hydrogen plants
- Commercial alcohol plants
Some common sources of producing CO
2 commercially include
the following:
- The gas plants which produce hydrogen or ammonia from coal, natural
gas, or other hydrocarbon feedstock produced CO2.
- CO2 is also produced in gas plants where large-volume
fermentation operations take place.
- For example: the production of ethanol by fermentation and the
manufacture of ammonia leads to the production of CO2 as a
by-product.
- Some commercial CO2 is produced from the combustion of
coke or other carbon-containing fuels.
- Breweries producing beer from various grain products also produce
carbon dioxide.
In gas plants, the carbon dioxide that is formed is available
commercially as:
- High pressure cylinder gas.
- Dry ice or relatively low pressure (about 300 psig) refrigerated
liquid.
Carbon dioxide plants gas can recover CO
2 from high-purity
or low-purity feed streams depending on various sources like ammonia,
ethanol or hydrogen plants. Feed gas clean-up technologies include PSA,
amine, and membrane systems.
Properties of Carbon
Dioxide
There are several physical and chemical properties of carbon dioxide which
we are depicting in the table below:
| Property |
Value |
| Critical density |
468 kg/m3 |
| Specific gravity |
1.53 at 21oC |
| Molecular weight |
44.01 |
| Stability |
High |
| Concentration in air |
370,3 * 107 ppm |
| Liquid |
Pressure < 415.8 kPa |
| Solid |
Temperature < -78oC |
| Henry constant for solubility |
298.15 mol/ kg * bar |
| Water solubility |
0.9 vol/vol at 20oC |
The carbon dioxide gas plants produce CO
2 which can be classified into
three categories:
- Ultra Pure - 99.999% pure CO2
- Industrial Grade - 99% pure CO2
- Beverage and Food Grade - 99.985% pure CO2
Uses of Carbon Dioxide
Carbon dioxide produced in gas plants are in two forms-liquid and solid CO
2
which are used as refrigerants, especially in the food industry. Solid CO
2
is called "dry ice" and is used for small shipments. CO
2 is widely
employed during the transportation and storage of ice cream and other frozen
foods. Some of the uses of CO
2 are mentioned below:
- Beverage: This gas is used to produce carbonated soft drinks
and soda water.
- Pressured Gas: It is used as a nonflammable pressurized gas
which is inexpensive. Pressured CO2 are inside canisters in life
jackets. Compressed CO2 gas is used in airguns, paintball
markers, for inflating bicycle tires.
- Fire Extinguishers: CO2 extinguishes flames.
- Welding: It also find its use as an atmosphere for welding.
- Solvent: Liquid CO2 is considered a good solvent
for many organic compounds. Here it can be used to remove caffeine from
coffee.
- Plants: Plants require CO2 to carry out
photosynthesis, and greenhouses can boost plant growth with additional
CO2.
- Medicine: In medicine, up to 5% CO2 is added to
pure oxygen. This helps in stimulating breathing and to stabilize the O2/CO2
balance in blood.
- CO2 Laser: The CO2 laser, a common
type of industrial gas laser uses CO2 as a medium.
- Oil Wells: Carbon dioxide is commonly injected into or
adjacent to producing oil wells.
- Metals Industry: It is used in the manufacture of casting
molds so as to enhance their hardness.
- Chemical Industry: It is used as a raw material in the
chemical process industry, especially for urea and methanol production.
Buyer's Guide
Specifications to consider for CO
2 gas plants are:
- Compression
- Contaminant remova
- Liquefaction and purification
- Refrigeration
- Water cooling
- Dehydration and water removal
Carbondioxide
Gas Plant
