Oxygen cycle - Wikipedia
Except for helium, which is mostly extracted from natural gas, oxygen, nitrogen and the other rare gases are extracted from the air that makes up Earth's. Keywords: Heat of combustion, stoichiometric air, excess air, natural gas Air contains Oxygen: Nitrogen in the proportion of or 1 mole of oxygen is. They are also the 2 major components of earth's atmosphere. compounds together like nitrous oxide, but there isn't a special relation ship b.
Wet bulb temperature is a critical parameter for sizing, and measuring the performance of evaporative-cooled cooling water systems. Otherwise, relative humidity is the percentage of the amount of water vapor actually present in the air, to the maximum amount that the air could hold under those temperature and pressure conditions. With the aid of a psychrometric chart, or its computerized equivalent, absolute values for water content such as weight fraction of ambient air, or weight-per-unit-volume of ambient air can be determined for any combination of dry bulb and wet bulb temperatures, or combination of dry bulb temperature and relative humidity.
This measurement is required to design various types of moisture removal or humidification systems.
Psychrometric Charts and Online Psychrometric Calculations: Psychrometric charts graphically represent the thermodynamic properties of air. They depict inter-relationships between multiple properties, such as temperature, moisture content, density and energy enthalpy. Charts can be drawn for various elevations.
For each elevation two known properties allow determination of all other properties plotted on the chart. Download psychrometric charts in pdf format, drawn for sea level one atmosphere conditions. International System SI Units Or use an online psychrometric calculator to generate properties for air. The liquid containing oxygen and argon is further purified by distillation in a second column. To obtain high purity oxygen, further distillation is needed and argon is removed.
Since air separation plants operate at low temperatures, construction materials have to be chosen carefully.
Aluminium alloys and stainless steel are frequently used. They do not become brittle at low temperatures. Efficient plant insulation is necessary to make the process economic and safe.Percent Oxygen in Air
Perlite an expanded rockglass wool and vacuum jacket techniques are commonly used Figure 5. Pressure swing adsorption can provide this and produce up to about tonnes a day. To produce oxygen, a stream of clean air is passed through a bed of alumina to dry the gas and then through a bed of zeolite molecular sieve.
Nitrogen is preferentially retained adsorbed leaving an oxygen-enriched gaseous stream to pass through Figure 7.
When the zeolite becomes saturated with nitrogen it is necessary to regenerate it. This can be achieved simply by reducing the pressure, whereupon the nitrogen is released desorbed back into the gaseous phase and rejected as waste. The sieve is totally regenerated in this way and is ready to repeat the cycle. Two beds are usually used in rotation.
Oxygen, nitrogen and the rare gases
One is used to produce the oxygen while the other is being regenerated. The full cycle time can vary between 2 and 8 minutes depending upon actual performance requirements. Instead of using a zeolite as in the manufacture of oxygen, nitrogen is produced from air using beds of carbon molecular sieve CMS.
Clean, dry, compressed air is passed through a bed of CMS typically at 7-I2 atm. Oxygen is adsorbed on the surface of the CMS and nitrogen passes through to storage.
- Oxygen, nitrogen and the rare gases
Analysis of the Products of Combustion - Combustion always occurs at elevated temperatures and we assume that all the products of combustion including the water vapor behave as ideal gases. Since they have different gas constants, it is convenient to use the ideal gas equation of state in terms of the universal gas constant as follows: In the analysis of the products of combustion there are a number of items of interest: This requires evaluation of the partial pressure of the water vapor component of the products.
This allows a simple method of determining the actual air-fuel ratio and excess air used in a combustion process. For ideal gases we find that the mole fraction yi of the i'th component in a mixture of gases at a specific pressure P and temperature T is equal to the volume fraction of that component.
Since from the molar ideal gas relation: