I. BOILER OPERATION
1. Boiler firing mode
During the steam supply process, the furnace must be in the correct combustion mode, which means ensuring that the fuel burns completely and if there is a lot of black smoke, more air must be supplied to the furnace to increase suction power. If you cannot see the smoke clearly, you must limit the air supply and reduce the suction power. If the smoke comes out gray, it is the best burning mode. When putting coal into the furnace, it must be spread evenly on the grate and added in small amounts to maintain even burning on the grate. Providing coal and raking slag must be done quickly and then immediately closing the coal furnace door.
We also need to pay attention to the thickness of the layer of charcoal and firewood on the recording surface, which is about 300mm. The slag is raked out using an ash door and a dust door. The scraping of slag and dust is done periodically and the operation needs to increase the suction power of the furnace by widening the smoke shield.
2. Steam supply
Fire the furnace until the pressure in the furnace is nearly equivalent to the maximum working pressure, then begin preparing to supply steam. Before supplying steam, the water level should be higher than normal. When supplying steam, ensure that the combustion mode is stable.
When supplying steam, we slowly open the main steam valve so that a small amount of steam heats the steam pipeline and drains all the water from the steam pipeline for about 10 ÷ 15 minutes. During this time, observe the phenomenon of pipe expansion. and pipe rack, if found normal, open the main steam valve fully to supply steam. The steam valve must be opened slowly and if it is fully opened, turn the steam valve steering wheel back half a turn.
To avoid steam mixed with water, water must be supplied into the boiler slowly, and the water level in the furnace should not be higher than normal according to the water tube.
3. Water supply
During boiler operation, the water level in the boiler must be maintained and should not be allowed to operate at the lowest or highest level for a long time. The boiler always ensures periodic water supply, with an intermediate water supply tank or hand pump (electric pump) taking care of this.
The furnace's intermediate water supply tank can be used as the main water supply pump for the furnace with the following operating sequence:
4. Oven cleaning mode
Periodic cleaning of the boiler is carried out for valves 6 and 7 in the diagram
Depending on the water supply regime for each purpose of using the furnace, the number of dirty discharges per shift is determined. The harder the feed water is, the higher the alkalinity and the more times the boiler needs to be flushed. At least in one shift, you must rinse dirty twice, each rinse for 2 to 3 times, each rinse for 10 to 15 seconds. Before discharging, we should raise the water level in the boiler to an average water level of about 25 to 50mm along the water pipe. The water tube needs to be cleaned at least twice per shift. The furnace's safety valve must also be checked once per shift.
5. Require water for the furnace
Primary water has total hardness not exceeding 0.5 mgdl/liter: PH = 7 ¸ 10
II. STOP THE BOILER
1. Stop the oven normally
Normal boiler shutdown is carried out in the following sequence:
+ First, close the steam supply valve and the steam release valve to the atmosphere by using the safety valve and gradually reduce the pressure of the furnace while raising the water level of the furnace to the highest level of the water tube by adding water to the boiler.
+ Second, stop supplying coal and close the coal door, closing the smoke shield
+ Third is to wait for the furnace to cool slowly with regular supervision by the boiler operator.
Draining water from the boiler for cleaning must be approved by the person in charge of the boiler and the water can only be drained when the steam pressure is at its fullest and the boiler water temperature is 70 - 80 C and at the same time we carry out the safety valve channel. gradually increased.
2. Stop furnace problems
Stopping furnace malfunction is carried out in the following sequence
The first thing we do is stop supplying fuel and air to the furnace. The smoke shield closes almost completely.
Second, quickly rake burning coal out of the combustion chamber.
Third, after stopping the fire, we close all the valves and smoke shields.
Fourth, close the steam supply valve and start letting the steam out of the safety valve channel.
Thursday Fill the oven with water
+ Let the furnace cool slowly under the supervision of the boiler operator and absolutely prohibit the use of water to put out fire in the boiler.
III. OVEN MAINTENANCE
- When the boiler stops operating for 1 month or more, we maintain it using the dry maintenance method.
How to do it: After the boiler stops operating, drain all the water from the boiler, open the valves, use clean water to clean and dry the furnace, and open the valves. Open the pipe cleaning door on the boiler body and use about 8 ¸ 10kg of quicklime with a lower size from 10 to 30mm placed on the aluminum tray and put into the boiler. Pile up the valves. Every 3 months we check and if we see that the quicklime is broken into powder, we replace it with a new one.
- When the boiler stops operating for less than 1 month, maintain it using the wet maintenance method
After stopping the operation of the boiler, we drain all the water from the furnace, wash the structure in the furnace, fill the boiler with treated water and light the boiler gradually increasing the furnace water temperature to 1000C. And the safety valve channels up to start releasing air. Close all valves and put out the fire.
IV. OVEN CLEANING AND MAINTENANCE
1. Cleaning
- Depending on the level of water supply and level of use, the boiler is normally cleaned every 3 to 6 months.
- Cleaning inside the oven is done using chemical methods. Combined with mechanical craftsmanship thanks to the door to clean the plumbing and clean the bottom of the oven.
2. Maintenance
- When the boiler is in operation, the entire boiler must be checked once every 1 month. Pay special attention to valves, water pipes, pressure gauges, and steam generation pipes to see if there are any leaks. Does ash accumulate at the bottom of the furnace? Record whether it is sagging or burned, whether the heat-resistant mortar layers are damaged, or whether the furnace is burned. If damaged, it needs to be repaired or replaced.
- From 3 to 6 months of boiler operation, the boiler must be stopped for comprehensive inspection and repair and combined with cleaning the furnace of scale.
- Boiler repair must be performed by individuals and units recognized by state law and must comply with current boiler standards and regulations.