42-square-meter boiling furnace – fails to start even after two attempts
Thread Content
A 42 square meter boiling furnace fails to start even when attempted twice; the fixed-bed boiling process does not work either. The fixed bed is 40–50 centimeters in size, and the pressure at the bottom of the furnace is only 4–5 KPa, yet the flow rate indicated is quite high. Just by increasing the air supply slightly, the flow rate exceeds 20,000 cubic meters. I would appreciate some advice from those with experience in this area. Thank you.
Could you be more specific about the situation? What material is used, where the driving takes place, and other parameters
This post was last edited by liziqiangyl on 2010-4-13 at 12:31. The furnace was originally designed for processing zinc ore concentrate, but it is now being used to process pyrite. The ore has been stored for over a year, and recently there were frequent occurrences of cold ash. After shutting down the furnace and cleaning it, the same problem arose once it was restarted again. The bottom material comes from the furnace after it has been cleaned and screened. The Pb content in the ore fed into the furnace is 1.72% – does this have any impact? 2# fuyun7118
With low bottom pressure, the flow rate is naturally high. There are two reasons: 1. There is air leakage from the furnace bed or air gaps exist; 2. The value of 40–50 for the fixed bed is too low – it should be increased to 65
1. Was a resistance test of the air cap conducted after the furnace was stopped and the debris removed? In other words, was it checked whether the air cap was severely blocked after cleaning it, as it is generally necessary to clean the air cap after such operations. If there is too much blockage, the air volume will not be sufficient. 2. Flow meter accuracy issues. It is better to bypass the flow meter and adjust the air volume based on experience, by observing the boiling condition of the material and pressure changes. 3. During the furnace startup process, it is necessary to monitor the changes in raw material particle size, air volume, and pressure.
It might be due to uneven air distribution; improve the air distribution in the ducts!
There is a problem of excessive size of the furnaces used for burning zinc concentrate; the roasting intensity is low, and the density of sulfur concentrate is relatively low, especially for ore that has been stored for a year as it becomes quite dry. It is recommended to increase the height of the material layer and raise the pressure at the bottom of the furnace accordingly； Reduce the size of the furnace ； Inspect the air cap and air chamber to check for any perforations in the air cap, as well as for any debris or damaged distribution plates in the air chamber ； The main reason is still the too low resistance, which causes direct perforation of the boiling layer; however, to identify the root cause of the problem, the available information is not sufficient
Overall, I agree with what was said above. The furnace used for zinc concentrate has been modified to burn sulfur concentrate. Due to its higher porosity, along with the lower density and particle size of sulfur concentrate – especially when the concentrate has been stored for a year and is quite dry – it is recommended to: 1. Increase the height of the material layer and raise the pressure at the bottom of the furnace accordingly ； 2. Increase humidity to maintain a moisture level of 8–9% ； 3. Check the air cap and air chamber: look for any perforations in the air cap, as well as any debris in the air chamber or damage to the distribution plate ； The main reason is still the low resistance, which causes direct perforation of the boiling layer; however, it is necessary to identify the root cause of the problem
Thank you to all the teachers; the problem has been resolved. After replacing the substrate, both the pressure and flow at the bottom of the furnace are now normal, and it has been operating successfully for over two hours. I guess the problem still lies in the base material. The material used before was slag removed from a dead furnace, filtered through a 5mm sieve; its particle size is large, and it does not match the flow rate required by the air cap holes.