Safe industrial boiler operation process

Boiler operating process and definition of boiler (boiler) is a pressurized device with the function of turning water into steam by means of heat energy obtained from burning fuel or converted from other energy sources such as electricity, atomic energy. Steam is supplied to industrial processes depending on the purpose. In addition, thermal power plants often use steam turbines to run generators, the steam used is superheated steam.

A. Check the boiler operating process system

Before burning and operating the coal-fired boiler, it is necessary to check the condition of the following parts:Before burning and operating the coal-fired boiler, it is necessary to check the condition of the following parts:

1. Valves, hand pump or electric pump, intermediate water supply tank (large pot), water tank, piping system have been assembled completely and according to technical requirements. Valves must be tight and easy to open and close.
2. Whether the assembled safety and measurement devices meet the technical requirements, the manometer must have a red line indicating the maximum allowable working pressure, the light tube must have a red line indicating the intermediate (horizontal) water level. between the water pipe) and the highest water level, the lowest water level is ± 50 mm from the average water level. The pressure-adjusted safety valve operates according to the rules:

• Valve working: adjustable at P_lv+ 0,2KG/cm²
• Check valve: set to P_lv+ 0,3KG/cm²

1. Inspect all boilers under pressure for damage.
2. Check whether the water supply for the boiler has enough reserve.
3. Check whether the fuel for the furnace has enough reserves and ensure the specifications.
4. The required operating tools are:

• 2m long spearhead crowbar
• Light rake 1.5m . long
• Double-toothed shovel 1.5m
• Hammer, wrench, wrench…

B. Boiler drying and kiln alkalizing

After installation, before putting the furnace into use, it is necessary to conduct drying and alkalizing the furnace to clean grease, rust, scale on the inner surface of the boiler operation process, to dry the bricks, mortar, furnace insulation.

1. Kiln drying and alkalizing are carried out simultaneously with the preparation for operation of the kiln and the starting of the kiln firing.
2. Chemicals to use kiln alkali are sodium hydroxide NaOH or trisodium phosphate Na .₃AFTER₄with the amount calculated to the alkalinity of the water l

The above chemicals, when used, must be mixed into a solution with a concentration of 20%, do not directly remove chemicals in solid form and the boiler operation process.

The drying and alkalizing of the boiler is done as follows strong :

• Pump the chemical solution into the pot, open the exhaust valve to let the gas out
• Pump the water supply into the pot to the highest line of the water pipe.
• Subsequent work is carried out such as preparing to operate the furnace and starting the furnace.
• During the period of about 6¸ 8h, maintain the small flame furnace and do not increase the pressure by venting the steam out according to the relief valve or the steam supply valve. Add more water to the oven if the water level drops.
• Close the relief valve, safety valve, or steam valve and increase the combustion mode to gradually raise the furnace pressure from 0 (P_lv-2)KG/cm²within 6 hours. When boiler pressure has been reached. (P_lv-2)KG/cm²maintain at that pressure for 12 24h
• During drying and alkalizing the kiln always keep the water level of the kiln at the highest line in the light tube.
• Stop burning the furnace for the furnace to depressurize and cool down, when the furnace pressure = 0KG/cm²and the temperature of furnace water <70⁰Open the drain valve to drain the water out.
• When the boiler has cooled completely, fill the furnace with clean water by turning the pump control knob by hand, then drain it. Pump like that for 3 times, then the job of alkalizing the furnace ends.

C. Furnace group and boiler operation process:

1. Prepare the furnace group:

Carry out the boiler operation procedures:

1. Exhaust valve, steam valve, safety valve close, open the air release valve to release gas, open the water supply valve for the furnace, open the circulation valve with the water pipe, open the 3-way valve of the manometer.
2. Close the power in the cabinet, the light indicates that the pump is on in manual mode. Pump water to the lowest level of the water pipe, check the tightness of the valves and flanges.
3. Close the water supply valve to the oven. Open the valve to pump water into the intermediate water supply, when it is full, close it.
4. Check the water level in the soft water tank if the water is dry it will not be able to start the burner
5. Put fuel into the combustion chamber by the following method:

• If burning firewood: Spread a layer of chopped dry firewood underneath, large firewood
• Substance above.
• If burning coal: Spread a thin layer of coal around the combustion chamber, in the middle of the dry wood.
• Open coal doors, vents, and smoke screens for naturally ventilated furnaces for about 15 minutes.
• Furnace group:

Use a dry rag soaked in igniter and put it into the combustion chamber. When the firewood is completely burned and the grate is covered with a layer of hot coal, we add a thin layer of coal on top, then close the furnace door and vent to let the wind blow weakly. The furnace grouping time is done slowly and lasts about 40 minutes.

When the furnace has steam, close the valves, increase the suction power and combustion process, check the status of the valves. Flush the water pipe, pressure gauge when the vapor pressure is from 1÷1.5kG/cm2 and important. monitor their activities. When the furnace pressure reaches 2kG/cm2, carefully use a short-hand wrench to block the nuts within the boiler. When the furnace pressure reaches the maximum working pressure, check the water supply system for the furnace by opening the steam valve, the water valve connecting the furnace and the intermediate water supply tank, if it is found that the water supplied to the furnace is normal. Raise the furnace pressure to work the safety valve, the safety valve must work and the manometer needle will exceed the red line a little.

The work of the furnace group is finished when the furnace pressure has been raised to the limit pressure and the operation of the furnace has been checked.

D. Boiler Operation Procedure

1. Oven burning mode

In the process of operating the boiler, the furnace must be in the correct combustion mode, ie, to ensure that the fuel is completely burned, if there is a lot of black smoke, it must provide more wind and increase the suction power; If the smoke cannot be seen clearly, it is necessary to limit the supply of wind and reduce the suction power. If the smoke is gray, it is a good combustion mode. Coal put into the furnace must be spread evenly on the plate and put in small amounts to maintain the burning on the plate. The operation of supplying coal and raking slag must be quick and then immediately close the door for coal.

The thickness of the layer of coal and firewood on the recording surface fluctuates around 300mm. Slag is scraped out by ash door, dust door. The scraping of slag and dust is carried out cyclically and the operation needs to increase the suction power of the furnace by expanding the smoke shield.

2. Steam level

When the pressure in the furnace is close to the maximum working pressure, prepare to supply steam. Before supplying steam, the clear water level should not be high. When supplying steam, the combustion mode must be stable.

When supplying steam, slowly open the main steam valve so that a small amount of steam heats up the steam pipeline and discharges all the standing water on the steam pipeline for about 10 15 minutes, while observing the expansion of the pipe and pipe rack. if it is normal, open the main steam valve all the way to supply steam. The opening of the steam valve must be slow, when fully open, turn back half a turn of the air valve steering wheel. To avoid the phenomenon of steam mixed with water, the water supplied to the furnace must be slowly, the water level in the furnace should not be higher than normal through the water pipe.

The above is a guide to safe boiler operation, students wishing to learn and obtain a certificate of boiler operation process, please contact us.