How is charring carried out in a vacuum furnace?

⑴Put on the protective equipment； ⑵Prepare tools and equipment such as walkie-talkies, ignition guns, F-wrenches, etc ； ⑶After shutting down, purge the furnace tubes thoroughly ； ⑷Isolate the furnace tube with a blind plate ； ⑸Remove the burnt wire blind flange ； ⑹Introduce unpurified air, and test each path for leaks to ensure smooth flow at the injection points ； ⑺Test the water supply and check for leaks in the cooling water lines at the furnace outlet and in the coking tank, and supply cooling water to these lines ； ⑻The oxygen content in the furnace and gas analysis is within acceptable limits ； ⑼After steam is supplied to the furnace tubes behind various control valves, the furnace is ignited and the temperature is raised at a rate of 80°C/h ； ⑽Control the heating rate properly, and raise the temperature of the furnace to around 500°C as specified ； ⑾Maintain a constant temperature; steam is supplied to each channel in turn and then stopped to remove coke, with one channel being processed at a time ； ⑿After the coking process is completed, and when the furnace temperature reaches 550°C, unpurified air is introduced gradually into each circuit, while reducing the steam supply to that circuit in order to carry out coking ； ⒀Keep the furnace temperature at around 600°C ； ⒁Adjust the ratio of steam to air to keep the color of the furnace tubes dark red ； ⒂Once the color of the furnace tubes darkens after full ventilation, it indicates that the burning process is complete; switch to full steam supply ； ⒃Cool down at a rate of 80°C/h; shut off the fire when the furnace temperature reaches 350°C, and use feedwater to flush the furnace tubes ； ⒄After flushing, drain the fluid, open all dampers, and allow natural cooling ； ⒅Tools and equipment such as walkie-talkies and F-wrenches should be put back in their proper places.