In recent years, i met some of charcoal plant boss and technical man and talked much about the drying process for the charcoal briquettes, i list these question as follows and give my idea for you reference:
- Fire happened in charcoal plant in the drying process;
- Will drying temperature is high or low, which is good for charcoal briquettes?
- How to deal with the damage problem?
- Moisture of briquettes after dried is not evenly?why?
I show my answer to above these question:
1.Fire were happened in drying process, is not only one technical man met in charcoal briquette plant, which is the technical development problem. The vertical dryer were widely used before belt dryer. So much hot air are block inside the dryer and can not escape, which make the briquettes temperature so much,fire happened is always!
For mesh belt dryer, the reason for fire by two reason:
— Fired dust from furnace. Usually, the biomass materials or coal will be used for fuel for dryer. Following the air flow pumped by draugh fan, the fired dust will be pumped into the dryer and contact with briquettes, fire will be happened inside;
How to do to deal with this problem?
— From the fuel of furnace, heavy oil, steam, gas can be fuel also, without fly ash, depends on your local cost;
— Try to build some “fire wall” inside and out side the furnace to block the flash ash if the coal only used for fuel;
— Change some hot pipe inside the dryer to block these problem happened;
— Hot air touched with briquettes for long time in one place: the temperature from furnace is around 250-350degree, and the touched with briquettes around 100-200 degree, and temperature inside dryer is around 200 degree. If the hot air touch with one place with one briquettes for long time, these briquettes temperature will be much and easy fired;
In order to avoid this problem, we need do some special designing for dryer, pls contact with me to get more technical support, info@dmsmacchina.com
2. As for the temperature inside the dryer
As our these years experience of charcoal briquettes drying, temperature inside the dryer shall be around 180-200 degree, and drying time depends on your briquettes moisture content! For example, normally the moisture is around 30%-35%, the drying time shall be around 4 hours or 4 hours half, or it can not be complete dried!
As you known, the moisture inside the briquettes after briquette press is upto 35%, which is very very high. The wet briquettes touch the high temperature, so surface will be dried soon. Now the problem is coming, the water inside the briquettes need to escape by heating from hot air! So you will see much briquettes are broken if the drying temperature is so high. On the other hands, the speed of mesh is very slowly, high temperature is easily to make fire inside the dryer!
So we need to control the temperature inside the drier to ensure the wet briquettes to dried slowly before the surface are complete dried.
Of course, for different kinds of briquettes drying temperature can be greatly different, such as coal, can be 250 degree, and for some of mineral briquettes, the temperature can be 300 degree!
But do you know how to control the temperature inside the dryer? Pls contact belt dryer manufacturer info@dmsmacchina.com
3. How to deal with the damage during drying process?
We need to clear the reason of briquettes damage before deal with the problem:
1. The activity quantity: there are two different kinds of activity are used in plant, one kinds of powder activity, other is liquid activity! But powder activity is popular because of easy operation and easy to do the constant work!
2.Temperature inside the dryer: so high temperature inside the dryer will make the surface of briquettes dried soon and moisture inside the briquettes need to escape , so the briquettes will be very weak, easy to damage;
3.Drop and break from one layer to other layer; the damage because of drop will be happen between 2nd layer to 3rd layer, because in that period, the briquettes are very weak, after two or three time drop, 20%-30% will be damaged!
Based above reason, we need to do the following control to reduce the damage rate:
1. Strictly control the activity quantity based on good quality;
2. Control the temperature inside the dryer,we recommend 180-200 degree for reference;
3. Do some update work on the dryer to reduce the height of two layers and make sure the briquettes fall down the second layer slowly!
Pls check our new designing on the dryer, do you see the different? Pls contact with simba lee to get more information, Email: info@dmsmacchina.com
