Image : http://www.flickr.com
Enter at your own risk! Security inflammatory signals may be affixed with its bright red flame graphics and the risk phrases say it all. You are in a limited area ...
Many people have a natural fear of chemicals that catch fire easily. In fact, I know some people who are so concerned that the chemical area, who have lost their concentration and playing with their activities, are visibly shaken. It is as if the whole place will explode in your faceat any time.
However, if this natural fear has the right to paralyze us, there will be no oil refineries, oil wells, or even service stations around the world. Industrial processes is a literary to a halt. People are so afraid to face these chemicals in their work.
This article find this natural fear, by the properties of flammable chemicals, so that people will take care of flammable chemicals, with respect, but not eliminate the fear.
Flashpoint
Chemicalsfuels are generally a low flash point. What is the lowest point flash? Is the temperature at which the chemical smoke to give enough to be caught fire when a lighted flame is brought near to it.
This means that a chemical flash point below ambient temperature under Enter vapors can ignite, even if they are stored at normal ambient temperature.
Thus, gasoline with a flashpoint of -20 degrees Celsius will already be able to captureFire at normal ambient temperature, when a flame of light is present, while kerosene has a flash point of 38 degrees Celsius, does not burn, though it remained at an ambient temperature of 30 degrees Celsius.
Well, this is completely false. To burn, they need three things at the same time present: fuel, oxygen and heat. When it comes to flash point, we speak of heat sufficient to produce gaseous vapors that can burn, but the chemistry will not burn, up to a higherThe temperature has been reached. This temperature is the point of ignition.
Ignition
The ignition can be achieved when a flame burning in the vicinity is to put the fuel gas or can be generated by a contact of electrical arcing or sparks even from mechanical shock. Very often, it can only generate sparks from static electricity.
Even if all these conditions are met, the fire will not start if there is not enough oxygensupport combustion. This is a very important factor to consider, especially for the storage of flammable chemicals.
Explosion limits
Have you heard the expression, a lean mixture or a mixture too rich? If I were really to be today with diesel or gasoline, surely know this. Auto mechanic to know that if the fuel in the engine, or too thin or too rich, the engine will not start. What does this mean?
Diesel and gasoline engines burn fuel veryfast. The combustion of fuel is so fast that the explosions inside the cylinder of the engine rather arise, they burn slowly like a gas stove.
The explosion of the air-fuel mixture is what gives the possibility of pistons that move the crankshaft of the engine again.
On the issue of the proper fuel mixture ...
There are a number of air-fuel mixture ratio that is right for the explosions. If the ratio is from this area, there can be no explosion.It is a lean mixture, if the amount of fuel is not enough to burn. Too much air to fuel is not enough.
When the fuel is further increased its holding, we reach the lower explosive limit or LEL. This is an explosive mixture.
If the fuel is further increased its stake, it becomes a fuel-air mixture ratio that is too rich to support combustion to achieve, which is too much fuel, too little oxygen. This point is the upper explosive limit or UEL. Both the LEL and UEL are expressed in percentageVolume.
Therefore, no percentage between the LEL and the largest error in the range of explosive. This is the range of explosive, which we have control of. In this area, the fuel is available, and air is present. We must be very careful not to get a spark or hot spot.
Let's take a hypothetical scenario. If someone has spilled flammable chemicals with low flash point in a room where the fumes will evaporate and fill the room. When the mixture of the lower limit of explosion, the whole mixture in space is obtainedcan explode if a source of heat inside This may take the form of an electric spark, is posed as if someone turns on the light.
If the chemical left over for a long enough time to fill the hall and to saturate the atmosphere. Then the mixture is too rich for combustion. E 'reached the upper limit of explosive, and the mixture will not explode, even if there is a spark. But this situation can be dangerous if a person opens the door andturn on the lights. The oxygen from the open door can only enough to reduce the rich mixture of an explosive mixture.
With this understanding, what do you think is more dangerous: a full of flammable chemicals, or a tank with only 1 / 4 full? If you're not sure is the answer of 1 / 4 full tank. With the two tanks have the same chance of heated pool, 1 / 4 full has more empty space, while the oxygen tank can holdalmost inevitably be saturated with fuel and do not have enough oxygen to burn.
But what happens when a chemical must be pumped into a tank full?
Inert Gas Systems
On tankers, if oil or other flammable oils is pumped out, the space occupied by the oil must be replaced, otherwise you will create a vacuum in the tank. This makes it impossible to continue the oil pump. To prevent the atmospheric air to the tank and suckingCreating an explosive mixture, inert gas, is conducted into the tank at a pressure slightly above atmospheric.
The inert gas containing mainly carbon dioxide and nitrogen, is produced by burning fuel in the boiler. The gas is pumped into the tank by means of fans. The oxygen content in exhaust gases are constantly monitored. Is usually around 5% and not support combustion. To prevent corrosion and contamination of oil to clean the exhaustpassing through a purification system. In this case, even if the tank is almost empty, the atmosphere on the chemical does not contain oxygen and not an explosive mixture.
Explosion Proof Fittings
It will be necessary during this type of flammable storage areas, chemical in order to avoid sources of heat that can cause an explosion. To avoid sparks, non-flammable storage of chemicals must follow certain safety rules with regard to ' Installationexplosion-proof and intrinsically safe electrical equipment, lighting, wiring and grounding.
Working with flammable chemicals should not be dangerous if you take the precautions necessary to avoid conditions that may be caused fires. So far we have talked about the technical. The other aspect of control is people. You must be competent.
Knowledge, training and development is necessary to avoid problems.
0 comments:
Post a Comment