I would like to ask everyone about the methods for collecting, transporting, and reusing the remaining coal under the coal support plates of side-loading coal cars
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Since our coke ovens were converted from top-charging to side-charging, the excess coal remaining under the coal carrying plate of the side-loading trucks has been transferred into the truck’s hopper using tricycles, and then transported back to the coal yard for reuse in the coke production. However, every time the tricycle is used to dispose of excess coal (except on rainy days), it’s in complete darkness; the excess coal spreads everywhere like flour, which is very harmful to the health of the operators, even though they wear dust masks. It’s even more terrifying when there’s wind; that scene... is so vivid! There are two reasons for this: first, the fineness of the remaining coal is very low (over 90% is less than 3 mm in size); second, the coal powder is relatively dry. When it rains, the moisture level in the coal hopper increases, and although there is no leakage during discharge, the flow of coal is often impaired. Does anyone have any good suggestions?
That’s a great question; we face the same issue. We have 6 buckets along the coal conveyor belt, and at first, after some time, we failed to secure them properly, which caused the buckets to fall. Later on, we simply opened that door, and sometimes the coal would flow onto the main road; then it was cleaned along with the rest of the debris on that road. Is there any good way to handle this? I hope everyone can give some advice.
Remove the bucket directly? It’s not very good; if there’s wind, it will blow everything around! Spilling it along the way makes it difficult to clean up.
6.25-meter rammed coke ovens and 5.5-meter rammed coke ovens are equipped with coal-conveying belts installed outside the platform on the machine side; small belts are placed under the coal-supporting bottom plates, and these belts are used to transport the coal powder that leaks during the coal loading process, as well as the coal powder from the coal-loading vehicles, to the central coal bin. On already assembled haulers, this method can also be considered: a small belt is installed on the outside of the hauler’s tracks to transport the excess coal to the central coal bin, from where it can then be removed using sealed vehicles. The coal can also be transported directly to the coal feeding belt, thereby preventing the coal dust from falling to the ground and reducing losses.
That makes sense. I’ve heard that on larger side-loading coal trucks, first of all, the amount of coal that leaks through the coal support plates is actually very small; secondly, they’re equipped with scrapers or small belts to convey the coal to a single point for discharge. However, in our case, maintenance workers need to frequently go through the coal hopper beneath the chain in order to inspect the chain, as well as the beams at the bottom of the coal support plates and the side support ribs (which are severely corroded). If small belts and scrapers were to be installed, there might not be enough space, and it could also affect the existing equipment management system, making implementation difficult.
As for the scraper you mentioned, dust is still generated when coal is discharged. It still depends on a comprehensive consideration of factors such as one’s own environment. The wind is strong here; no matter what you do, it’s pitch black. The operating environment nowadays is much worse than before!
At present, there are only three types: scraper conveyors, plug valves, and belt conveyors. We encourage everyone to consider whether there are better options for technological upgrades in their own factories.
Is the wind direction relatively constant where you are?
It’s basically quite fixed: in one valley, it’s the south wind in the morning and the north wind at night. The operations involved have a significant impact on one another.
Wow! :) It’s really relatively fixed! I have thought of a method that might help alleviate the situation, but I can’t say it will solve the problem completely; moreover, it’s only applicable to my factory’s circumstances! Please offer guidance, discuss, and provide references! Specific methods: First, following the dust removal approach used with high-pressure ammonia in bridge pipes, a pipe can be installed on the side of each coal unloading port. Water nozzles that face inward and are positioned corresponding to the coal hopper’s discharge opening can be used; high-pressure water (pressure is key – the type of water isn’t important; 2.5 MPa to 3.0 MPa is sufficient) is sprayed to create a negative pressure effect, which helps in sucking away dust (coal powder). A dust collection port can also be installed at the coal discharge opening to further assist in dust removal. The coal dust sucked in by this vacuum pipeline and high-pressure water hose flows along the pipeline into the drainage ditch on the machine side; another pipeline (two pipelines in total) is placed at the bottom of this ditch, leading to a collection tank. After sedimentation, the coal dust is then removed and sent back to the coal storage area. Selection of high-pressure water: 1. An onboard option can be chosen, which involves installing the water tank and high-pressure pump directly on the vehicle ； 2. High-pressure ammonia water can also be used directly; the advantage is that there is no need to invest in onboard water tanks, pumps, etc., but the downside is that the ammonia smell in the collection tank and when transporting it back to the coal yard will be quite strong. Additionally, the ammonia pipes need to be connected to the main dust removal pipeline using flexible connectors, which must be pressure-resistant and leak-proof – this represents another practical challenge. Moreover, due to the high pressure, safety considerations are also necessary ； II. Similar to the first method, a high-pressure water main is required; the difference is that it’s more thorough, as no additional tricycle is needed to transport the coal ； In the upper middle part of each coal hopper, several water outlets are installed along the direction of the hopper wall; water is used to wash the coal powder, which then flows into the high-pressure water main. Nozzles are placed at the top of the main, directing the water in an inclined pattern for spraying, after which it flows into the water pipes located in the grooves on the side of the machine. At this point, the function of the high-pressure water nozzle is no longer to create negative pressure; it merely serves to increase the fluidity of the slurry water. Therefore, such high a pressure isn’t necessary – as for exactly how high it should be, I still lack experience in this regard! We are still exploring the above methods on our own at the moment, assessing their feasibility. If anyone has any good ideas or suggestions, please feel free to share them so we can discuss them together!
1. Place a cloth bag at the discharge opening of the remaining coal hopper, allowing it to hang inside the tray of the tricycle. 2. Increase the frequency of coal discharge – do not wait until the remaining coal is dry before discharging it