Active In SP
Joined: Nov 2009
26-04-2010, 10:57 AM
please could you send me the seminar and presentation on aqua silencer asap or could you atleast send me links. i really need it bad.
Active In SP
Joined: Apr 2010
01-05-2010, 11:49 PM
Air pollution is most important from the public health point of view, because every individual person breathes approximately 22000 times a day, inhaling about 15 to 22 Kg of air daily. Polluted air causes physical ill effect decides undesirable aesthetic and physiological effects. Air pollution can be defined as addition to our atmosphere of any material, which will have a deterious effect on life upon our planet. The main pollutants contribute by automobiles are carbon monoxide (CO), unburned hydrocarbon (UBHC), oxides of nitrogen (Nox) and Lead. Automobiles are not the only source of air pollution, other sources such as electric power generating stations, industrial and domestic fuel consumption, refuse burning, industrial processing etc. also contribute heavily to contamination of our environment so it is imperative that serious attempts should be made to conserve earthâ„¢s environment from degradation. An aqua silencer is an attempt in this direction, it is mainly dealing with control of emission and noise. An aqua silencer is fitted to the exhaust pipe of engine. Sound produced under water is less hearable than it produced in atmosphere. This mainly because of small sprockets in water molecules, which lowers its amplitude thus, lowers the sound level. Because of this property water is used in this silencer and hence its name AQUA SILENCER. The noise and smoke level is considerable less then the conventional silencer, it is cheaper, no need of catalytic converter and easy to install.
Basically an aqua silencer consists of a perforated tube which is installed at the end of the exhaust pipe. The perforated tube may have holes of different diameters. The very purpose of providing different diameter hole is to break up gas mass to form smaller gas bubbles The perforated tube of different diameter is shown in fig. 2. Generally 4 sets of holes are drilled on the perforated tube. The other end of the perforated tube is closed by plug. Around the circumference of the perforated tube a layer of activated charcoal is provided and further a metallic mesh covers it. The whole unit is then placed in a water container. A small opening is provided at the lop of the container to remove the exhaust gases and a drain plug is provided at the bottom of the container for periodically Cleaning of the container. Also a filler plug is mounted at the top of the container. At the inlet of the exhaust pipe a non-return valve is provided which prevents the back flow of gases and water as well.
As the exhaust gases enters in to the aqua silencer, the perforated tube converts high mass bubbles in lo low mass bubbles after that they passes through charcoal layer which again purify the gases. It is highly porous and posses extra free valences so it has high absorption capacity. After passing over the charcoal layer some of the gases may dissolved in to the water and finally the. exhaust gases escape through the opening in to the atmosphere. Hence aqua silencer reduces noise and pollution.
EFFECTS OF DISSOLVED GASES ON WATER
The water is a good absorbing medium. In aqua silencer the gases are made to be dissolved in water. When these gases dissolved in water they form acids, carbonates, bicarbonates etc, Action of dissolved SO2 :When Sox is mixed in water, it form SO2, SO3, SO4, H2SO4, H2SO, i.e. sulfur Acid ( H2SO3,), it forms Hydrogen Sulphide which causes fol rotten egg smell, acidify and corrosion of metals. Action of dissolved CO :2 The dissolved carbon dioxide forms bicarbonate at lower PH and Carbonates at higher PH. This levels 40-400 mg/liter. The form a scale in pipes and boilers. The carbon dioxide mixes with water to form Carbonic acid. It is corrosive to metals and causes green house effect. Effect of dissolved NOx :The Nitrogen in water under goes Oxidation to form ammonia, Nitrate, Nitrite, Nitric acid. This synthesis of protein and amino acids is effected by Nitrogen. Nitrate usually occurs in trace quantities in surface water. A limit of 10 mg per liters Nitrate is affordable in drinking water. METHODS TO CONTROL THE WATER POLLUTION In aqua silencer the water gets polluted by the dissolved gases As in above topics said these gases are mixed with water to form carbonate, acids like carbonic acid, sulfuric acid, and Nitrous acid etc. the petroleum products contains phenols which gives suffocating smell. The sulfur gas mixes with water to form hydrogen sulfide, which give rotten egg smell. These should be controlled to minimum the water pollution. There are two methods: 1) Lime water wash method 2) Absorption process
LIME WATER WASH METHOD
The water is treated with the calculated quantities of slaked lime. One should have the quantitative analysis of water to go for this process. After mixing the heavy precipitates settle down as sludge at the bottom of the tank are removed from time to time. Lime can neutralize any acid present in the water. SO2 , gases are removed from the flue gases forming calcium sulphate. The precipitates dissolved carbon dioxide as calcium carbonate and converts bicarbonate ions into carbonates. The equations are given below. The SO gas is removed from the flue gases forming calcium sulphate 2 Ca(OH) + SO ........ CaSO + H2o 2 2 3 Neutralizes any acid present in water 2HCL + Ca(OH)2 ..........Cacl2 + 2H2 H2SO4 + Ca (OH)2 ........... CaSo4 + 2H20 Precipitates bicarbonate as calcium carbonate CO2 + Ca(OH)2........CaCO3+2H2O Precipitates bicarbonate as calcium carbonate Ca(HCO3)2 + 2Ca (OH)2 ......... 2CaCO3 + 2H20 Converts bicarbonate ions (Like NaHCO , KHCO3 etc.) into carbonates. 3 NaHCO3 + Ca(OH)2 ............ CaCO3 + H20 + Na2 CO3
LIMITATIONS OF LIME WATER WASH METHOD
Amount of neutralization capacity is limited It is very difficult to handle Bridging and form are formed It is expansive Regeneration is possible Lime in any form it is difficult to handle
Activated charcoal is available in granular or powdered form. As it is highly porous and possess free valencies. So it posses high absorption capacity. Activated carbon is more widely used for the removal of taste and odorous from the public water supplies because it has excellent properties of attracting gases, finely divided solid particles and phenol type impurities, The activated carbon, usually in the powdered form is added to the water either before or after the coagulation with sedimentation. But it is always added before filtration. Feeding devices are similar to those used in feeding the coagulants.
ADVANTAGES OF ABSORPTION PROCESS.
It increases the coagulation power of the process. Its use reduces the chlorine demand. The excessive dose of activated carbon is not harmful. The treatment process is very simple and it requires nearly no skill. The efficiency of removing color, odour and taste is quite high. It can be easily regenerated It has excellent properties of attracting gases.
The aqua silencer is more effective in the reduction of emission gases from the engine exhaust using perforated tube and charcoal, v By using perforated tube the backpressure will remain constant and the sound level is reduced. v By using perforated tube the fuel consumption remains same as conventional system. v By using water as a medium the sound can be lowered and also by using activated charcoal in water we can control the exhaust emission to a greater level. v The water contamination is found to be negligible in aqua silencer. v It is smokeless and pollution free emission and also it is very cheap. This aqua silencerâ„¢s performance is almost equivalent to the conventional silencer. It can be also used both for two wheelers and four wheelers and also can be used in industries.
v Internal Combustion of Engines v v Environmental Pollution Analysis Engg. Chemistry Jain & Jain Khopkar M. L. Mathur R. P. Shrma
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