Chapter Combustion (Updated 5/31/10)
Nitrogen, Oxygen and Argon: The Primary Atmospheric Industrial Gases Products . Useful definitions and relationships related to water content and other .. below shows changes in the concentration of CO2 in air at the Mauna Loa test site. Air is a mixture of gases whose second major component (21% by volume) is oxygen, next to nitrogen. What is the difference between nitrogen and oxygen? If we test the oxygen percentage at industrial area, the amount of oxygen level . What is the physical state of oxygen at room temperature? Gas. What is the Describe the relationship between nitrogen, oxygen, and air. Identify each item as.
They are equal when air is at its dew point or saturation temperature. The difference between the dry bulb and wet bulb temperatures is an indicator of the humidity level. Wet-bulb temperature is the lowest temperature that water will reach by evaporative cooling, and that temperature is almost always lower than dry bulb. 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.
BBC Bitesize - GCSE Chemistry (Single Science) - The atmosphere - OCR Gateway - Revision 2
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.Flavored Oxygen Taste Test
Furthermore, since the sum of the component volumes Vi must equal the total volume V, we have: Using a similar approach we determine the partial pressure of a component using Dalton's Law of Partial Pressures: Assuming complete combustion and a total pressure of 1 atm Develop the combustion equation, and determine a the percentage of excess air, b the air-fuel ratio, and c the dew point of the combustion products. The First Law Analysis of Combustion - The main purpose of combustion is to produce heat through a change of enthalpy from the reactants to the products.
Oxygen, nitrogen and the rare gases
From the First Law equation in a control volume, ignoring kinetic and potential energy changes and assuming no work is done, we have: We have adapted some of these tables specifically for this section, and these can be found in the following link: 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. Perlite an expanded rockglass wool and vacuum jacket techniques are commonly used Figure 5.
Oxygen, nitrogen and the rare gases
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.
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.
When oxygen saturation is reached a second bed is brought on-stream, retaining continuity of supply and the first vented to atmosphere to desorb the oxygen and hence regenerating the CMS prior to the next cycle.