HOW TO CHECK COAL QUALITY BY VISUAL INSPECTION
Hi, all my power plant study users today we discussed a very important topic which is related to power plant operation you all know very well about in power plant electricity generation takes place with the help of combustion of coal into the boiler furnace and steam generation take place which is used in turbine for electricity generation. our company ordered coal from different-2 states for running the unit smoothly if coal quality is good then our fuel consumption is reduced if coal quality is not good in that condition our coal consumption will be maximized here the question is arises how to check coal quality by usual inspection before that coal sends to the laboratory for testing purposes. in this article, we mainly focus on this thing that how we can check the coal quality by usual inspection. With the help of power plant experts as well as power plant engineers we collected some data which is very useful for checking the coal by the usual method. Here are the observations which help you for knowing the quality of coal by usual inspection.
OBSERVATION REGARDING VISUAL INSPECTION OF COAL
| SR. NO. | OBSERVATION | Inference on coal quality (Probable limits are given for relative estimation) |
| 1. | Very bright shining coal jet black, in section all layers appear shining, the coal does not leave stains on palm fairly light can be easily broken by hand. | 1. Caking coal (brighter the lustre, stronger the caking) 2. Ash fusion (1000-1100 Deg. C) 3. Lower ash content (10-20%) 4. Low volatiles (15-20%) 5. Low inherent moisture (1-2%) 6. High calorific value (5500 to 6500 kcal/kg) |
| 2. | Moderately bright, jet black. In section alternate layers are shining and dull does not leave stains or palm, heavier than (1) above, not so easy to break by hand. | 1. Medium caking 2. Ash fusion little more (1100 to1200 Deg. C) 3. Ash content (15-20%) 4. Volatiles (20-25%) 5. Inherent Moisture (1-2%) 6. Calorific value (5000 to 6000 kcal/kg) |
| 3. | Moderately bright, in section alternate layers are bright and dull, but white streaks are seen between layers. Do not leave a stain. Reasonably light, not easy to break. | 1. Medium caking 2. Lower ash fusion (1000 to 1100 deg.C) 3. Higher ash content (20-30%) 4. Volatiles (20-25%) 5. Inherent moisture (1-2%) 6.Calorific Value (4500 to 5000 kcal/kg) 7. More unburnt expected. |
| 4. | Quite dull brown appearance. In section, no layers seen bur uniform smooth grain structure, curved surface acquired on breaking. Hard to break, fairly heavy. Do not stain your hand. | 1. Weakly caking or even non-caking. 2. High ash fusion (above 1200 Deg. C) 3. High ash content (25-35%) 4. High volatiles (25-35%) 5. Higher inherent moisture (3-5%) 6. Calorific Value (4800 to 5800 kcal/kg) |
| 5. | Dull black appearance. All fibrous structure, Very light. Looks exactly like charcoal. Leaves a heavy black stain on the hand. Very soft to break. | 1. Non-caking 2. Low ash fusion (1100-1200 C) 3. High ash content (25-30%) 4. Low volatiles (20-25%) 5. Moisture (1-25%) 6. Calorific Value (4500 to 5500 kcal/kg) 7. Very heavy fine formation on the grate |
| 6. | Dull brown colour. In section rough gains. Breaks with a flat surface. Very heavy. Leaves no stain. Cannot be broken easily. | 1. This is no coal at all, but either a shale piece. 2. Very high ash (70-80%) 3. Ash fusion (above 1100 Deg. C) 4. No volatiles 5. Little inherent moisture 6. Difficult to ignite and burn. 7. Very low Calorific Value (1200 to 1500 kcal/kg) |
I hope this article HOW TO CHECK COAL QUALITY BY VISUAL INSPECTION helps you clear all doubts regarding the visual inspection of coal if you like this article then shred this with your power plant job mates as well subordinates.