In today's context, many aluminum plants in China utilize roasting and anode open roasting furnaces, with most of them following a 48-hour flame shift cycle. Typically, these systems operate with either six or seven furnace chambers, which has proven effective so far. However, this method is not without its drawbacks. After the baking process is completed, there is a need to transition from the 48-hour flame shift cycle to a 36-hour cycle suitable for normal production. Additionally, the operation must be shifted from six or seven chambers to five chambers. The conventional methods for such transitions involve using a transition curve or a hysteresis shift, both of which are time-consuming and complex.
Drawing on our experience with open-type roasters both domestically and internationally, and leveraging the advanced combustion heating control equipment imported from SETARAM, as well as the unique use of domestic fuel gas for calcining, we have introduced a new approach. This includes a 36-hour flame shift cycle and an eight-chamber operation system. Not only does this setup meet the required heating rates, but it also simplifies the transition from the oven curve to the normal production curve significantly.
The specific oven used in the roaster is a load-bearing type, featuring two flame systems and an 8-chamber configuration with a 36-hour flame shift cycle. The ignition starts in the 23rd furnace chamber, and initially, three chambers are connected in series. As temperature increases, the fourth chamber is added after three flame cycles, followed by one additional chamber per subsequent cycle until all eight chambers are active. Previously, the movement involved shifting the exhaust frame forward, but now, the entire system operates more efficiently.
The oven follows a 288-hour heating curve, with a 36-hour interval for each temperature rise and a cooling period of 432 hours. During the process, several challenges were identified. For example, controlling the negative pressure at the nozzle during ignition was critical. Once the flame stabilized, maintaining the right balance between the side and middle fire paths was essential. Additionally, the 800°C heat preservation section had some issues with curve control. Temperature differences between the upper and lower parts of the fire channels were observed, with variations up to 100-90°C in medium-temperature furnaces and about 50-60°C in low-temperature ones, influenced by flue gas volume.
After 12 days of heating and 18 days of cooling, the furnace chambers showed minimal deformation. There was no bulging, cracking, or material falling off. Some minor expansion was noted in certain areas, but overall, the structure remained intact. The thermal expansion of refractory materials matched expectations, and no significant sinking was detected.
This oven uses natural gas as fuel, and during the trial run, a 3-hour operating cycle with a 36-hour flame shift was implemented. Before ignition, two closed chambers were filled with filler materials, and then anode carbon blocks were loaded. The load-bearing design allowed for minimal negative pressure loss, reducing the risk of structural deformation. Moreover, the oven and production could run simultaneously, saving energy effectively.
Following the 288-hour heating curve, the transition to a 180-hour production cycle took only six flame shifts (nine days), losing one chamber every two cycles. The temperature remained stable throughout, and the quality of the anode carbon blocks was unaffected.
The physical and chemical properties of the produced anode carbon blocks met the necessary standards and were successfully used for electrolytic baking.
In conclusion, the 36-hour flame shift cycle of 288 hours proved simple to operate, with a smooth and stable transition to the normal production curve. The simultaneous operation of oven and production improved efficiency and saved energy. The controlled heating rate of 8°C/h ensured no damage to the furnace structure. Lastly, the trial-produced anode carbon blocks met all quality requirements and were used for the start of electrolytic baking.
Gift bag is a kind of packaging goods, it used to package gift bag. A beautiful gift bag can have a good effect on the gifts.Our company gift bag material is usually plastic with colorful PP material , support patterns and LOGO customization.Gift bags can be used many times in a cycle. Nowday more and more people using gift bags everywhere.Gift bags with custom designs and slogans also have a promotional functions
Gift Bag,Portable Gift Bag,Oil Resistant Gift Bag,High Grade Environmental Gift Bag
shaoxing chaofeng stationery manufacturing CO.,LTD. , https://www.chaofengstationery.com