Protection atmosphere of ammonia decomposition hydrogen and nitrogen production machine - application in bright annealing furnace
To ensure the safe operation of ammonia decomposition hydrogen production, nitrogen generator, and bright annealing furnace equipment, this safety operating procedure is formulated. Operators must strictly follow this procedure:
1、 Operators must undergo three-level safety education and pass assessments before they can take up their posts.
2、 Furnace opening safety regulations:
1. Before starting the furnace, routine inspections must be conducted on electrical appliances and machinery. Electrical appliances and equipment must be in good condition and grounded firmly;
2. Turn on the ammonia decomposition furnace normally. To ensure the normal supply of gas.
3. When the annealing furnace temperature reaches 200 ℃, start to supply cooling water;
When the furnace temperature reaches 600 ℃, pass N2 and clean the furnace with N2.
When the furnace temperature reaches 800 ℃, the oxygen content in the furnace is less than 0. At 5%, release ammonia gas.
Strictly prohibit pouring steel strips.
7. After each shutdown, the H2 and N2 hoses must be disassembled.
Smoking and open flames are strictly prohibited in the workplace.
3、 Shutdown safety regulations
1. Cut off the power supply to each heating zone and cut off the power to cool down (100 ℃/time). The temperature balance in each district has decreased.
When the furnace temperature drops to 800 ℃, replace the ammonia decomposition gas with nitrogen gas. After the fire in the exhaust pipe is extinguished, continue to clean the furnace hall with low flow nitrogen until it reaches 600 ℃ and stop filling nitrogen.
3. Stop the fan when the furnace temperature drops to 300 ℃.
4. Stop water supply when the furnace temperature drops to 200 ℃.
5. After the annealing furnace is completed, there should be a guide strip left in the furnace for the next start-up.
4、 In case of a power outage, the power can be restored within 5 minutes. A small amount of nitrogen can be filled into the furnace, otherwise follow the shutdown safety regulations. If ammonia decomposition gas is cut off, nitrogen gas with a flow rate of 12m3/h will be immediately transported into the furnace. Ensure the normal pressure of the atmosphere inside the furnace. And shut down the furnace.
Operating rules for opening and closing the furnace
1、 Open the furnace
Before starting the continuous bright annealing furnace for strip steel, the ammonia decomposition furnace should be turned on normally. Dry the purification tower to ensure the dew point requirement of the atmosphere. And connect the nitrogen and ammonia decomposition gas stainless steel bellows.
2. Check whether the wool felt at the furnace mouth is well sealed, whether the guide belt is worn, whether the transmission electrical appliances, manual cutting, etc. are all normal.
3. Turn on the stove and slowly raise the temperature. Basically, it rises at a rate of 100 ℃ per hour. Turn on the cooling water at 200 ℃.
Turn on the air-cooled motor on the cooling section at 4.400 ℃.
At 5.600 ℃, nitrogen gas is injected at a rate of 8m3/h. Fill the furnace with nitrogen at a rate of 16m3/h when the O2 content is below 5ppm at 700 ℃.
At 6.700 ℃, turn on the oxygen controller. And notify ammonia decomposition to prepare for air supply.
When the furnace temperature reaches 800 ℃ and the oxygen controller is less than 2, replace nitrogen with ammonia decomposition gas. The gas supply gradually increases from small to large until it reaches 20m3/h. The nitrogen valve can only be turned off when it is completely stable.
After turning off the nitrogen for 15 minutes, ignite the exhaust gas released from the furnace head vent pipe.
When the furnace temperature reaches the working temperature, the following should be checked: cooling water temperature (not greater than 50 ℃), mixed gas pressure (greater than 150mm/water column), and furnace pressure (positive pressure). When the furnace reaches 1000 ℃, proceed with the test strip.
2、 Turn off the furnace
When the temperature drops to 800 ℃. It must be converted from ammonia decomposition gas to nitrogen gas, and the nitrogen filling time should be greater than 30 minutes. Control the flow rate at 15m3/h and slowly shut off the ammonia decomposition gas within 2 minutes. After the fire in the exhaust pipe is extinguished, nitrogen gas is added at a rate of 15m3/h for 10 minutes, and then nitrogen is added at a rate of 5m3/h until it reaches 400 ℃. Simultaneously turn off the oxygen meter.
When the furnace temperature reaches 300 ℃, turn off the air-cooled section motor, cooling water, and all power sources, and shut down the furnace. And remove the intake hose of nitrogen and ammonia decomposition gas.
3、 Unexpected fault handling
1. During work, there may be a situation where the ammonia decomposition gas is stopped due to power outages or ammonia shutdowns. The manual and electromagnetic valves for nitrogen filling should be turned on in a timely manner to maintain a stable intake volume. If there is a temporary shortage of nitrogen gas, the nitrogen filling bypass can be manually opened instead.
2. If there is a power outage during the operation of the equipment, the ammonia decomposition gas should be changed to nitrogen gas in a timely manner. If the amount of nitrogen is not enough, the nitrogen bypass can be opened manually, and the furnace should be powered off to cool down.
3. If the cooling water exceeds the temperature limit, the regulating valve on the cooling water outlet should be adjusted. Reduce the water resistance by increasing the flow rate and lowering the water temperature.
4. If the water supply is stopped during work, nitrogen should be filled and the temperature should be lowered to prepare for shutdown. Quickly identify the cause, and if it cannot be resolved in a short period of time, immediately shut down the furnace.
5. Strip breaking treatment: When the steel strip is broken in the furnace, the furnace is cooled to 800 ℃ and the nitrogen gas flow rate is changed to 18m3/h. Observe and ignite the vent pipe 2 minutes after the fire is extinguished. (1) If there is a fire, continue to charge nitrogen at a rate of 18m3/h. After 15 minutes of extinguishing the pipe, open the front and rear pressure plates and wool felt. Wear a belt. (2) If there is no fire, switch to a flow rate of 10m3/h. After 15 minutes, open the front and rear pressure plates, wool felt, and put on the straps.
4、 Several situations can be resolved:
1. There is a flame at the top of the ammonia decomposition reactor:
The reason may be a leakage in the reaction tank. Stop working, turn off the ammonia decomposition furnace inlet and outlet switches, and vent. Inject nitrogen gas into the furnace from the thermocouple sleeve, and shut down the furnace according to the shutdown operation rules. After the furnace temperature drops, drop it out for pressure testing and maintenance.
2. Freezing of evaporator and upper pipeline:
The reason for the excessive traffic is to reduce it appropriately. Just rinse with warm water or cooling water,
Fire at the mouth of furnace 3:
The reason is that the broken belt is broken from the hot state inside the furnace, which can be extinguished by nitrogen flushing or dry powder extinguishing. Be careful not to pull the hot steel strip out of the furnace when it breaks, in order to avoid accidents.
4. Mars falling inside the protective covers on both sides of the annealing furnace:
The reason is that there may be thermal looseness and ignition between the silicon carbon rod and the clamp. You can stop heating and tighten it or add a little aluminum foil. Be careful not to use force to prevent the silicon carbon rod from breaking. Restart heating.
5. There are sparks at the flange of the furnace and cooling section:
The reason is that the bolts at the flange connection are loose, and the asbestos packing has aged after long-term use. Nitrogen flushing can be used to extinguish the fire, or dry powder can be used to extinguish the fire. Then tighten the screws or replace the graphite packing after the furnace is shut down.
Instructions for the Operation Process of Bright Annealing Furnace
1、 Hot furnace start-up method:
A hot furnace refers to a furnace where the temperature must be above 800 ℃. Before injecting ammonia decomposition gas into the furnace, first use 99% pure nitrogen to inject from the ammonia decomposition device into the pipeline, flow meter, and muffle tank. When preparing to inject ammonia decomposition gas into the furnace, first open the vent valve and let it go. Then fill the furnace with ammonia decomposition gas.
2、 The normal operating temperature of ammonia decomposition equipment cannot be lower than 750 ℃. Do not introduce any hydrocarbon gases during use to prevent explosions. It is safer to start the nitrogen generator and blow it with nitrogen gas before passing ammonia to decompose hydrogen gas.
3、 Handling method for sudden power outage during normal use:
In the event of a short-term power outage (about 15 minutes), operators should not be nervous because both the furnace and ammonia decomposition furnace have a certain amount of heat, which is sufficient to ensure gas supply to the furnace within 15 minutes. If there is no call within 15 minutes. Shutdown the furnace according to the "Shutdown Safety Regulations".
4、 Shutdown treatment:
Shutdown the furnace to achieve balanced cooling, that is, all four temperature zones should reach the same temperature before cooling down. The reason for the decrease after 100 ℃ is due to the action of the fan. The cooling rate varies among the four temperature zones. Not conducive to the lifespan of muffle.
5、 When the furnace is shut down for a long time and restarted, the ammonia decomposition furnace and adsorption tower should be activated and regenerated. Ensure the dew point quality of ammonia decomposition gas during furnace start-up* Let's take turns baking towers A and B once.
Six. When replacing the felt, stop the air cooling section motor and turn on the nitrogen knife at the felt replacement furnace port. Seal the door and maintain the pressure inside the furnace.
