Industrial gas is a group of gases that are commercially manufactured and sold for uses in other applications. The most common industrial gases are: air gases – Oxygen (O2), Nitrogen (N2) and Argon (Ar) rare gases – such as Helium (He), Krypton (Kr), Xenon (Xe) and Neon (Ne) and other gases like hydrogen (H2), Carbon Monoxide (CO), Carbon Dioxide (CO2) and Nitrous Oxide (N2O), Chlorine (Cl2), Hydrogen Chloride (HCl) and Sulphur Dioxide (SO2), Acetylene (C2H2), Methane (CH4) and Propane (C3H8). In addition, there are many different mixtures of these and other gases to meet the needs of specific applications.
Usage in the Industry:
The industrial and medical gases industry serves a very large number of customers in the whole community. Industrial gases are essential for almost all manufacturing. Large quantities of oxygen, nitrogen and argon are used in the basic and infrastructural industries. Shipyards and the automotive industry use acetylene, propane, mixtures of fuel gases and oxygen for cutting and welding. Liquid nitrogen is vital in recycling plastics, packaging and scrap tyres. The chemical industry employs all major industrial gases as a raw material or for inerting. The other smaller market segment consists of cylinder gas and mixtures.
In India, there are presently over 300 small & medium size plants and approximately 25 large tonnage plants all over the country. These gases are supplied through pipelines to captive customers in adjacent factories; in cryogenic transport tanks for bulk deliveries to long distance customers; or filled in cylinders. The present annual turnover of the gas industry, excluding captive production is about Rs. 3,000 crores ($650 million). With increased industrialization, the demand pattern of industrial gases is also changing fast. Modern application in the food processing industry, agro industries, healthcare and technology are growing at a tremendous pace. This has driven the industry to adopt stringent quality control systems and an efficient distribution network. Major players in India include BOC India, INOX Air Products Ltd., Jindal Praxair Oxygen Co. Ltd., Air Liquide India Holding P.Ltd. Aims Industries Ltd etc.
The Indian gas industry is growing at an average rate of 12 per cent per annum during the last couple of years, with the industrial oxygen growing consistently at 15-17 per cent per annum. The growth of industrial gas industry can be easily forecast on the basis of projections of the steel and other metallurgical industry.
Steel demand is seen rising by 10% in the fiscal year to march 2011, helped by higher spending on infrastructure will continue to drive growth of the gas industry. Natural gas comprises 9 % of India’s primary energy consumption and it will be 14% of energy mix by 2010. Demand for natural gas is also likely to increase at an average annual growth rate of 7.3%.Metals production and fabrication will continue to be the largest market for industrial gases, accounting for 31% of total demand in value terms in coming years. The second largest market will be the chemical processing/petroleum refining segment. The medical/healthcare market, though smaller in size, will be the fastest growing and record gains from the expansion of healthcare services in developing nations and rapidly increasing use of home healthcare respiratory therapies in advanced economics. Hydrogen is gaining prominence and most companies are striving to develop technologies that can efficiently exploit the potential of hydrogen. Increased use of natural gas will create an opportunity for higher production of argon and carbon dioxide. The Industrial gas industry has a very bright future in the coming years.
Global Industrial Gases Market Revenue:
According to the Freedonia Group, Inc., a Cleveland-based industry research firm, world demand for industrial gases is forecast to increase 6.9% annually to $36.8 billion in 2011, with volume exceeding 300-bcm (billion cubic meters). Asia/pacific is the largest consuming region because of rapid growth in developing industrial markets, especially those of china and India.
The four products viz. a) Compressed Oxygen, b) Liquid Oxygen, c) Nitrogen and d) Liquid Nitrogen are all produced from air in the same plant. Air, the raw material is liquefied cryogenically and the separation of the two components liquid oxygen and liquid nitrogen takes place in a fractional distillation column. Compressed oxygen and nitrogen gases are bottled into cylinders by compressors / pumps after vaporization of the respective liquid fractions.
The air is first compressed in 3 stages to a pressure of 30kg/cm2. Thereafter the removal of water vapor and carbon dioxide take place in a battery of molecular sieves. The out-going carbon dioxide and water vapor free air is further compressed to a pressure of 100 kg/cm2 and cooled substantially by external refrigeration. This high-pressure air is cooled further in heat exchangers by the outgoing product gases. Bulk of this cold air is allowed to expand through an expansion engine and the remaining air is routed through an expansion valve. The downstream air of the expansion engine attains a pressure of 5 kg/cm2 and a considerably reduced temperature. The other stream of air going through the expansion valve (Joule-Thomson valve) is expanded to also attain a pressure of 5kg/cm2) whereby partial liquefaction of air takes place.
Both the streams of air are mixed and introduced as a liquid vapor mixture to the bottom column of the double rectification column (fractional Distillation Column). Due to mass and heat transfer at every perforated tray in the column the nitrogen rich liquid vapor accumulate at the top trays and an oxygen rich liquid-vapor mixture collect at the sump of the column. The liquid nitrogen accumulating at the upper portion of the bottom column is drawn out as product for storage in Vacuum insulated cryogenic tanks. For production of nitrogen gas, this liquid nitrogen is pumped from the storage tank through vaporizers for gasification and bottling into cylinders.
The oxygen rich liquid-vapor mixture at the sump of the bottom column is routed to the top column of the distillation column, which is at a lower pressure of 0.5kg/cm2. In this low-pressure column further separation of oxygen and nitrogen vapor, take place through a mass and heat transfer process at the various trays within the column. The separated oxygen vapors again settle at the bottom of this column and condense to form liquid oxygen due to exchange of heat with the colder liquid nitrogen formed at the top of the bottom column. This liquid oxygen accumulating at the bottom portion of the top column is drawn out as product for storage in Vacuum insulated cryogenic tanks. For the production of compressed oxygen, this liquid oxygen can be vaporized by the heat exchange between the incoming process air and compressed by oxygen compressors for bottling into cylinders. Or else the stored liquid oxygen can be pumped through vaporizers for gasification and bottling into cylinders.
Depending upon requirements, the production modes of the plant can be altered to produce:
1) liquid nitrogen and compressed oxygen where the in-built vaporizers are used to fill compressed oxygen and 2) liquid oxygen only, where external vaporizers are used to fill compressed oxygen.
The raw material for the Oxygen and Nitrogen (gas and liquid) is atmospheric air. Besides this, the plant will require consumables like lubricants, greases, catalysts and chemicals, which are available indigenously.