Thursday, December 31, 2009

Coal Handling

Coal is a solid fuel containing ash, therefore the use of coal would involve high costs for equipment required for handling and the combustion of coal. It aims to eliminate all dust and ashes. Coal handling security needs, because there are some problems in the handling of coal, among others:

a. Coal can be burned alone
b. Coal may cause explosion
c. Coal may cause pollution, if there are strong winds dust flying everywhere

Burned OWN
Coal can be burned themselves after experiencing a gradual process that is:
1. The first stage: first coal will absorb oxygen from the air slowly and then the temperature of coal will rise
2. The second stage: as a result of rising temperatures speed coal absorbs oxygen from the air temperature increases and then will reach 100-1400C
3. The third stage: after the temperature reaches 1400C, vapor and CO2 are formed
4. Step four: up to temperatures of 2300c, isolation of CO2 will continue
5. Stage five: when the temperature was above 3500C, this means that coal has reached the point quickly fired and will burn

Cause Burned Own
Coal is an organic fuel, and if touched directly by air in high temperature conditions (eg. prolonged drought) will burn itself. This situation will be accelerated by:
 a. Exothermic process (steam and oxygen in the air), this is the most common
b. Bacteria
c. Catalytic action of inorganic objects

While the possibility of burning yourself, especially among other things:
 a. Low carbonization
b. Sulfur high levels (> 2%). Threshold levels of 1.2% sulfur should

Fighting The Coal Burned Own
 When the accumulation of coal stockpiled a closed place (indoor storage) then the rules must be made so that the warehouse is clean of dust deposits of coal, mainly found in the surface equipment. Thus it is necessary to continue treatment and constant. If the landfill is open (outdoor storage) should be chosen so that the flat and not humid, it is to avoid infiltration impurities (impurities). For coal fly high substance spray should be used (sprinkler). Coal storage too long, too dangerous, we recommend a maximum of 1 month.

High Pile
The high pile of coal piles are difficult to determine because each landfills have their own conditions such as climate, humidity, radiation.

Symptoms Of Early Checking Burned
a. Checking Temperature
To determine the maximum temperature of the pile of coal can be 1-2m below the surface of the pile. Here's how: create a vertical hole assisted by perforated pipes. Utility pipes to the hole no longer being buried in coal use for the temperature inside the perforated holes with temperatures in the pile.

b. Coal may cause explosion
Coal dust explosion caused by:
1. Dust particle size: <20 mesh (= 0.833 mm) 2. There is a relationship between the substance and the degree of explosions fly Volatile (%) Volatile ratio = -------------------------------- Volatile (%) + Fixed carbon (%) If volatile ratio> 0.12 then the possibility of coal dust explosion is always there. When the components of coal ash in the dust> 70-80% will not need to fear the danger of explosion. Conditions for the burst will occur when the particles smooth floating time. Also the burning gases in the air can help the explosion.

c. How to control the explosion
1. Use an inert gas (N2 gas). Gas is expensive enough, but it evaporates too quickly, so always be checked pressure valve. Put this N2 gas cylinders in storage pulverized coal bin, also in part filter (B/F)
2. Cleaning done periodically to avoid the formation of coal dust deposits
3. Eliminates the possibility of achieving a point source of ignition point in the installation
4. Watch, look and find the source of the fire as early as possible
5. In the case of coal deposits is covered with plastic to keep your O2 concentrations less than 12%. In an open heap, use water spray using an automatic sprinkler system will be very helpful in preventing coal fires.

Following way : control panel operator (CPO) in the pipe put in heaps of coal and then fit in a certain temperature. If the temperature increases and the piles of coal-fit temperature exceeds the COP, the automatic sprinkler watering will work itself is a pile of coal.

Treatment of coal dust
Plastic sheets cover the coal pile is the best, sought not to use dark-colored plastic. Heap is compacted with a bulldozer to reduce the presence of oxygen in the sidelines of coal. On the open surface of coal heap pile should be sprayed with a hardened surface of liquids. This fluid is an additional product from oil refinery.