LSB Coal Gasification Environmental Protection Steam Boiler

1、 Structure Introduction
The LSB coal gasification environmentally friendly steam boiler adopts the most advanced combustion technology, where fuel is fed from the coal feeding port onto the grate for combustion, and then converted into coal gas. After being converted in the combustion chamber, the flue gas enters the upper part of the furnace and is ignited by an automatic ignition system to generate high-temperature flames, which radiate and convective heat transfer to the heating surface. The small carbon black and dust contained in the flue gas are cut and rotated by multiple layers of tube bundles, and the purified flue gas is re burned and discharged into the atmosphere through the chimney.
2、 Boiler characteristics
1. Boiler characteristics
(1) Compact structure, easy installation and migration, small footprint, and low infrastructure investment.
(2) The flue gas is forced to rotate and flush the convection tube bundle, fully utilizing the heating surface and improving boiler efficiency.
(3) Due to the multiple return and circulation of flue gas, the goal of dust removal in the furnace is fully achieved.
(4) Water sealed slag removal prevents the spread of dust and is a new type of green and environmentally friendly product.
3、 Factory Overview
1. Boiler host;
2. Chimney;
3. Valve instruments (see accessory list);
4. Technical documents; Provide factory technical documents to users along with the furnace.
Installation Instructions
4、 Preparation before installation:
After the boiler is transported to the site, in order to install it quickly, the following work must be done:
1. Determine the installation company and verify the qualification certificate. Organization and staffing:
The boiler installation unit must have a boiler installation qualification certificate issued by the superior competent department that meets the installation scope, be responsible for contacting the local boiler supervision agency, filling out the installation notice, and accepting the installation supervision and inspection of the local boiler inspection and testing unit. After installation is completed, the installation unit and the local boiler supervision agency jointly conduct installation quality acceptance. And timely handle the registration and household registration procedures for boiler use in accordance with relevant regulations. The unit using the boiler should have a dedicated person responsible for the boiler installation work. During the boiler installation, the boiler operator should participate and be equipped with plumbers, fitters, lifting workers, refrigeration workers, welders, and auxiliary workers.
2. Installation quality requirements:
① Boiler installation should comply with design requirements and meet the requirements of GB50273-1998 "Code for Construction and Acceptance of Industrial Boiler Installation Engineering".
② The insulation of boilers, their ancillary equipment, and thermal pipelines shall comply with the requirements of GB4272.
3. Seriously study relevant materials
Relevant personnel should carefully study the "Steam Boiler Safety Technical Supervision Procedure" (96), boiler drawings, installation and use instructions and other technical documents to understand and master installation, lifting, operation and other matters.
4. Determine installation location
(1) It is best to choose an installation location close to the steam consumption point, in order to shorten the pipeline, reduce infrastructure costs, and minimize heat dissipation losses.
(2) Convenient water supply and drainage.
(3) The storage and transportation of fuel and ash are convenient.
(4) The boiler should be installed and transported smoothly.
(5) The layout of the boiler room should comply with the provisions of Chapter 8 of the "Steam Boiler Safety Technical Supervision Regulations" (96) of the Ministry of Labor. The lighting should be sufficient, the ventilation should be good, and there should be no water accumulation on the ground. To ensure convenient operation and maintenance, there should be a gap of 3 meters in front of the boiler, 2.5-3 meters behind the boiler, and no less than 1 meter on both sides.
(6) It is strictly prohibited to stack toxic and flammable materials in the boiler room.
(7) The door leading to the outside of the boiler room should open outward, and the windows of the rest room should also open outward.
5. Foundation preparation
Construct the foundation according to the foundation map, and the thickness of the concrete can be determined based on the geological conditions. When mixing, the proportion of sand and gravel concrete should be appropriate. Please refer to the foundation drawing for specific dimensions and technical requirements.
5、 Installation of large boiler components
1. Acceptance of steam boiler equipment
(1) After the boiler is transported, the components are counted according to the manufacturer's factory list, and the integrity of the equipment is checked based on the boiler drawings. The large parts of the boiler are inspected for any damage or deformation during transportation.
(2) When unloading large boiler components, one end can be tied with steel wire rope on both sides of the base, and the other end can have a lifting ear inserted into another steel wire rope to find the lifting center and slowly lift the boiler. The lifting equipment has a capacity of not less than 10 tons. After the boiler leaves the vehicle, place the exchange rack in the appropriate position, slowly seat the boiler, and avoid damaging the pipe seat.
(3) When the boiler is in place, it must be in an upright position. When standing upright, the top lifting ears of the boiler should be lifted with lifting equipment, and no other parts should be tied.
(4) After the boiler is in place, the front, back, left, and right should be kept horizontal with a permissible inclination of no less than 5mm. Otherwise, the lower parts should be elevated with shims.
(5) There should be no large gap between the boiler and the foundation, and it is required to be tight without air leakage. Cement should be used to fill the gaps where there are gaps.
6、 Installation of chimney and air distribution equipment
When installing the chimney, asbestos ropes should be embedded between the flanges, and the inclination of the chimney should be checked using a lifting line. If there is a deviation, steel wire ropes and flower blue bolts can be used to tighten the flange connection. Note that the tension of the three iron wires should be roughly equal. When installing air distribution equipment, it should be ensured that the air valve is adjusted flexibly and there is no air leakage at the connection of the air duct.
7、 Installation of pipelines, valves, instruments, and accessories
1. Install according to the pipeline, valve, and instrument drawings. The electric pump should be fixed in the appropriate position and the foundation should be poured. After connecting the power supply, it should be tested for operation.
2. Safety valve
1. The safety valve should be installed after the boiler water pressure test is completed, and the working pressure of the safety valve should be adjusted during the initial ignition.
Adjust the pressure according to Table 7-2 of Article 143 of the "Steam Boiler Safety Technical Supervision Regulations" of the State Administration of Labor.
① Adjustment method for safety valve:
Remove the opening pin, remove the top cover, loosen the hexagonal lock nut, and then turn the adjusting screw to loosen or tighten the spring to achieve the required exhaust pressure of the safety valve. Tighten the locking nut after adjustment, and then install the remaining parts properly.
② The boiler is equipped with a safety valve, and the set pressure of the safety valve is detailed in Table 2
The set pressure of the safety valve for this model of boiler is 0.43MPa.
Table 2

Rated steam pressure MPa
Setting pressure of safety valve
≤0.8
Work pressure+0.03MPa
Work pressure+0.05MPa
After the safety valve reaches the specified set pressure, it should be sealed with lead. Unless the safety valve is calibrated, it is not allowed to dismantle the lead seal without authorization at any time.
③ When adjusting the safety valve, the water level in the drum should be slightly lower than the normal water level, and be prepared to allow water to enter at any time after the safety valve is opened.
④ Do not tap any part of the safety valve. Only the control rod on the valve can be used to open the safety valve.
⑤ The boiler must not be used before the safety valve is adjusted.
Regular attention should be paid to whether the safety valve is functioning properly. Due to the effect of water vapor, in order to prevent the valve disc and seat of the safety valve from sticking, regular exhaust tests should be conducted every 2-4 weeks to verify the opening and closing function of the safety valve. The safety valve should be installed after the hydrostatic test. The safety valve should be connected to the exhaust pipe to direct the steam to a safe location in the boiler room. The safety valve should be installed vertically. Valves are not allowed to be installed on guide pipes.
3. The sewage pipe should be connected to the sewage tank or other safe place, and the pipeline should be fixed to prevent accidents such as burns during sewage discharge.
4. The steam pipes outside the main steam valve shall be connected by the user unit, and there shall be at least one elbow on the main steam valve pipeline. Otherwise, expansion pipes shall be installed, and the outer wall of the pipeline shall be insulated.
5. The deviation between the water level gauge and the normal water level line of the drum is ± 2mm. The markings for the highest safe water level, lowest safe water level, and normal water level should be accurately marked. The water level gauge should have a drain valve (or drain plug) and a drain pipe connected to a safe location. The lower drainage pipe of the water level gauge must be connected to a safe place. The water level gauge cock should rotate flexibly and not leak water. Lighting equipment must be installed at the water level gauge for easy observation.
6. After the pressure gauge is installed, a red line should be drawn on the dial to indicate the maximum allowable working pressure of the boiler. The pressure gauge cock should work flexibly and not leak water. The drainage should be unobstructed, and the pressure gauge tube should not be insulated.
7. It is strictly prohibited to use a pressure gauge in any of the following situations:
(1) When there is no pressure, the pointer of a pressure gauge with a limited stop pin cannot return to the limit pin after rotating; A pressure gauge without a limiting pin may have a pointer above zero when there is no pressure, exceeding the allowable error specified for the pressure gauge.
(2) The glass surface is broken or the dial scale is unclear.
(3) Seal damage or exceeding inspection period.
(4) Surface leakage or pointer jumping.
Instructions for Use
8、 Inspection before baking and boiling
Before baking and boiling, it is necessary to conduct a detailed inspection of the boiler and its components, with the following inspection items:
1. Whether the manhole and handhole are tight, and whether the accessory parts and devices are complete.
2. Whether the steam pipeline, water supply pipeline, and sewage pipeline are complete.
3. Is the smoke passage unobstructed.
9、 Oven and boiling furnace
After the installation of all components of the boiler, and after inspection and trial operation, it is confirmed that the conditions for safe start-up of each standard component are met, the process can begin.
1. During boiling, appropriate chemicals need to be added to the boiler to make the boiler water alkaline and remove impurities such as oil stains.
2. Boiling can use drugs such as sodium hydroxide (NaOH) or trisodium phosphate (Na3PO4.12HO), and the dosage is calculated based on the boiler volume per cubic meter of water. Use 2-3 kilograms of medicine per cubic meter. The above-mentioned drugs used for boiling should be prepared as a uniform solution with a concentration of 20%, and solid drugs should not be directly added to the boiler.
3. Close all pipe sockets and hand holes, main steam valve seat and water level gauge drain cock, open the upper manhole, pour the prepared drug solution into the boiler drum at once, then close the manhole and open the safety valve to allow air and steam inside the boiler to be discharged outward.
4. Inject the treated water into the boiler, and the inlet water temperature is generally not higher than 40 degrees Celsius. C， When the water level in the boiler reaches 2/3 of the water level gauge, close the water supply valve. After the water level in the boiler stabilizes, observe whether the water level has decreased, and check whether there is any leakage in the manhole cover, handhole cover, flange joint, and drain valve of the boiler. If there is any leakage, tighten the bolts.
5. Open the ignition door: Lay a layer of 100-200mm thick coal slag on the grate, and ignite it with firewood (strictly prohibited from using wooden boards with iron nails), cotton yarn or other ignition materials. Start gradually adding coal when the ignition material is on high fire.
6. The firepower should be gradually increased to avoid sudden heating. During this time, the blower should be turned on for forced ventilation. The primary air vent should be adjusted to 20%, and the secondary air vent should be adjusted to 30%. If the primary air is too strong at this time, coking is likely to occur. When the coal seam reaches about 300 millimeters and the furnace is in full swing, the coal seam should be thickened to about 800 millimeters. In general, the retention layer is 150-200 millimeters, the fire layer is 150-200 millimeters, the reduction layer is 200-300 millimeters, and the space above the coal is not less than 300 millimeters.
7. The boiler pressure gradually increases to 0.1 megapascals and is maintained for about 12 hours, then the combustion is stopped to gradually decrease the pressure by 0.05 megapascals, and the water temperature is below 70. After C, open the drain valve and release all the sewage.
8. After the boiler has cooled down, open the manhole and handhole covers, rinse the inside of the boiler with clean water, and inspect it. If any dirt is found, follow the above method (ignite with firewood, raise water for no less than 3 hours) to boil the boiler until there is no oil stain inside the boiler drum.
10、 Raise the fire
1. Before starting the boiler, a comprehensive inspection (including relevant accessories and management) should be conducted before supplying water. The drain valve must be closed before water enters. Open the safety valve to allow the air from the boiler to be discharged.
2. Slowly inject the treated water into the furnace, with the inlet water temperature generally not exceeding 40 degrees Celsius. C， When the water level in the boiler rises to the lowest level on the water level gauge, close the feedwater valve and wait for the water level in the boiler to stabilize before observing whether the water level has decreased.
Special emphasis should be placed on carefully checking whether the coal filling port and inspection port meet the strict sealing requirements before starting the fire. If they cannot meet the requirements, the debris on the sealing surface should be removed and gaskets should be embedded to ensure strict sealing
The purpose of sealing. Due to the forced ventilation combustion of the furnace, no combustion gas is allowed to leak out during operation to avoid accidents.
3. When starting the fire, open the bottom coal feeding port and place the wood ignition material on the grate. After all the inspection ports are closed, ignite the ignition material. After the ignition material burns vigorously, start adding coal. When the coal seam burns vigorously, continue adding coal. After adding coal, close the furnace door, seal it tightly, and open the blower to allow the coal to continue burning. Strengthen the observation of the fire situation to gradually normalize the combustion.
4. When igniting, the temperature should not be too fast to avoid excessive thermal stress in different parts due to different heating, which may affect the service life of the boiler. The time from the cold furnace to the steam pressure to the working pressure during the initial ignition should be 3-4 hours. In the future, except for special situations where steam is urgently needed during ignition, the cold furnace should not be less than 2 hours and the hot furnace should not be less than 1 hour.
5. After raising the heat, attention should be paid to changes in the water level in the pot at all times, as the water level will rise after heating. If it exceeds the water level gauge, drainage can be carried out.
6. When steam is emitted from the opened safety valve, the safety valve should be closed and the pressure gauge pipe and water level gauge should be flushed. When the air pressure rises to 0.1 megapascal (1 atmosphere), check the manhole and handhole cover bolts, and at the same time, check whether the drainage is tight and leak free.
7. When the pressure inside the boiler gradually increases, attention should be paid to whether there are any special noises from various parts of the boiler. If there are any, the cause should be immediately checked, and if necessary, the boiler should be stopped immediately for inspection. Only after the fault is resolved can it continue to operate.
11、 Coal addition and slag removal
The consumption of different types of boilersThe coal loading interval can be determined according to the heat consumption and load requirements, depending on the amount of coal used. The coal entering the furnace must be granular coal with a uniform particle size of 15-65 millimeters and a coal powder content of no more than 5%. The slag discharge time, frequency, and amount are determined based on the amount of coal consumed.
It is generally required to observe the fire frequently, adjust it frequently, observe the color of the combustion chamber ignition through the observation hole, observe the combustion condition, and adjust the size of the primary and secondary air flow in a timely manner. The size of the secondary air flow is particularly important for the combustion of gas.
When you hear the whistling sound of gas burning, it may be that the combustion is not strong. At this time, turn off the blower first, and then turn the movable grate handle back and forth about several times. If you feel that the turning is easy, there may be slagging and empty shed on the grate surface. At this time, open the lower furnace door for ignition, and the thickness of the slag layer should not be less than 200 millimeters. If there is unburned red fire falling during slag removal, stop slag removal, close the slag removal door, open the upper furnace door for coal addition. Before adding coal, first burn the ignition coal on the grate vigorously, then turn on the blower and open all the air doors for 2-3 minutes. Quickly close the air doors, open the coal addition port for 2-3 minutes, and then add coal. Closing the fan and opening the coal filling port are continuous actions that cannot be delayed. If the air valve is closed and delayed for a period of time before opening the coal filling port, it may cause gas explosion and pose a danger. When opening the coal filling port, the operator must be on the side of the opening of the coal filling port. When opening the coal filling port, the skylight should be opened to avoid gas leakage and danger to the operator. After adding coal, close the furnace door and seal it strictly.
Each time coal is added, the air damper should be closed once, and the blower should be turned off five minutes later, in order to allow the secondary air to burn off the unburned fire and blow out the residual gas in the furnace. After about ten minutes, the furnace door should be opened,
Special attention: When opening the furnace door, the operator must not stand directly in front of the door or approach the door to look inside the furnace. People should try to avoid the front of the observation hole to prevent flames from spraying and injuring people. After adding coal, close the furnace door and turn on the blower to allow the coal to burn slowly. When there is pressure inside the boiler, open the auxiliary steam valve to supply steam to the lower part of the grate. The opening of the valve should not be too large, and it is advisable to avoid coking in the furnace hall. This valve is always open during boiler operation. At this point, turn the air inlet of the blower to 50%, and after running for half an hour, all the air inlet of the blower will be opened, and the boiler will enter normal operation. The electronic igniter is an automatic device. When the blower igniter starts, it automatically works. After the furnace gas burns normally, the igniter automatically stops working; If the combustion chamber is extinguished and the automatic control system alarms, the stoker should promptly investigate the cause to ensure normal operation of the furnace; The stoker should regularly inspect and test the automatic ignition system; To prevent malfunction and the occurrence of explosions in the furnace (remember to follow the principle of "fire waiting for gas" instead of "gas waiting for fire").
12、 Supply of steam
When the steam pressure in the pot approaches the working pressure, prepare to supply steam to the outside. Before supplying steam, the water level in the pot should not exceed the normal water level, and the combustion in the furnace should be stable during steam supply.
When supplying steam, the main steam valve should be slightly opened to allow a small amount of steam to warm up the pipes. At the same time, the drain valve on the pipeline should be opened to release condensed water. The warm-up time depends on the length, diameter, steam temperature, and other conditions of the pipeline, generally not less than 10 minutes. During warm-up, attention should be paid to the expansion of the pipeline and the condition of the pipeline support. If any abnormal conditions are found, the warm-up should be stopped and the faults and defects should be resolved. After the pipeline is heated and the condensed water in the pipeline gradually decreases, the main steam valve can be fully opened. The opening should be done slowly, and attention should be paid to whether there are any special conditions in the boiler components. If necessary, the boiler should be checked immediately. If necessary, the boiler should be stopped for inspection. After the main valve is fully opened, the main valve wheel should be returned half a turn to prevent defects such as inability to rotate due to thermal expansion. After the boiler is supplied with steam, the auxiliary parts, valves, and instruments should be inspected again for any air leaks. Is the work functioning properly. To prevent the water level from flooding the glass tube under any circumstances due to hanging water (steam carrying water), and the main steam valve should not be opened too wide, it is generally controlled between 1-2 turns. Under normal combustion conditions, the rated output can be achieved.
13、 Normal operation
During boiler operation, it is required to ensure that the boiler water level is normal and the steam pressure is stable. Maintain the boiler room
Neat, do a good job in shift handover, prioritize human factors, and strengthen inspections of various mechanical equipment and instruments. Ensure safety and reliability, prevent accidents, pay attention to saving coal, and the stoker should regularly summarize experience and continuously improve their technical level.
1. Water supply requirements:
The boiler feedwater needs to be treated and meet the requirements of GB1576-2001 "Industrial Boiler Water Quality".
2. Pay attention to the water level in the pot and keep it within the range of ± 50 millimeters of normal water level. It should not be higher or lower than the highest or lowest water level. The water level in the water level gauge generally has a slight shaking phenomenon. If the water surface is still, there may be blockage in the water level gauge, and it should be flushed immediately.
3. Water level gauge:
Each shift should flush the water level at least once to keep the water level gauge glass clean and ensure that the water level is clear, correct, and reliable. If water or steam leakage is found in the glass gasket, it should be filled quickly. If the glass is blurry but clear, or the water level line is unclear, and even after rinsing, it still has no effect, it should be replaced.
4. Water supply equipment:
(1) All feedwater pumps should be checked for normal operation during shift handover, and any malfunctions should be repaired immediately.
(2) Boiler feedwater should adopt continuous water inlet as much as possible, and control the fine water flow at the outlet valve of the water pump.
5. Steam pressure:
Regularly pay attention to pressure changes, try to maintain stable pressure inside the pot, and do not exceed the maximum working pressure.
6. Pressure gauge:
The pressure gauge bend should be flushed once per shift to check if the pressure gauge is normal. If any damage is found, the boiler should be immediately shut down for repair or replacement. To ensure the correctness of the pressure gauge, the selected pressure gauge should meet the requirements of relevant technical standards, and its inspection and maintenance should comply with the regulations of the national metrology department. Before installation, the pressure gauge should be calibrated and the next calibration date should be indicated. The dial of the pressure gauge should be marked with a red line, and the pressure gauge should be sealed after calibration. The accuracy of the pressure gauge should not be less than 2.5 levels.
7. Safety valve:
Pay attention to whether the safety valve is functioning properly. To prevent the valve disc and seat of the safety valve from sticking, the steam pressure should be increased every 2-4 weeks for exhaust testing to check the function of the safety valve.
8. Discharge valve:
Regular discharge (refer to the discharge chapter)
9. Normal operation
(1) The normal combustion conditions in the furnace should be: a flat fire bed, dense and uniform flames, and neat and consistent. It is generally required to observe the fire frequently and adjust it frequently. By observing the color of the combustion chamber through the fire observation hole, the size of the primary and secondary air flow can be adjusted. The size of the secondary air flow is extremely important for gas combustion.
(2) It is necessary to continuously adjust the boiler load and combustion chamber operating conditions according to the steam usage situation to ensure the stability of boiler steam pressure. The steam department should strengthen communication with the boiler. When there is a change in steam consumption, it is best to notify the boiler room half an hour in advance.
(3) Boiler and accessories (including pipelines, valves, instruments) are safe, sensitive, and reliable.
(4) The boiler room is clean and tidy, with bright lighting.
(5) Both parties involved in the shift handover must ensure thorough and serious handover, and record the situations and issues encountered during the handover in the operation log book.
14、 Water quality requirements
The feed water of the boiler is generally treated with chemical treatment outside the boiler. When conditions do not permit, it is allowed to use chemical treatment inside the boiler. When adding chemicals to the boiler, it is necessary to supervise the scaling, corrosion, and water quality of the boiler. The water quality requirements for boilers should comply with the relevant provisions of GB1576-2001 "Industrial Boiler Water Quality".
15、 Pollution discharge
Generally, water contains more or less minerals. After the feedwater enters the boiler and vaporizes, minerals remain in the boiler and concentrate to a certain extent, then settle down in the boiler. The greater the evaporation rate, the longer the operation time
The longer the sediment, the more sediment it will accumulate. To prevent boiler damage caused by scale and slag, it is necessary to ensure the quality of the boiler water. The alkalinity of the boiler water should not exceed 1.25 milliequivalents per liter. If it exceeds the above range, the boiler should be drained. Generally, when the testing conditions are not yet complete, it should be determined according to the specific situation, such as draining once a day per shift.
Attention should be paid to the following matters when discharging pollutants:
1. When two or more boilers use the same discharge manifold, attention should be paid to:
(1) It is prohibited to discharge two boilers simultaneously.
(2) If another boiler is undergoing maintenance, it must be separated from the drainage pipeline before discharging to prevent water from flowing back from the other boiler.
2. Wastewater discharge should be carried out at low loads and high water levels. When discharging, close attention should be paid to the water level inside the furnace, and it is advisable to lower the furnace water level by 25-50 milliliters per discharge.
3. If the end of the sewage pipe is not connected to the sewage box or sewage well, and there is no protective equipment, it must be confirmed that there is no one near the sewage pipe before discharging to avoid accidents during discharge.
4. The specific operation during discharge is as follows:
Each boiler is equipped with two drain valves. When draining, first fully open the second valve (the one far from the boiler), then slightly open the first drain valve (the one closest to the boiler) to preheat the pipeline. After the pipeline is preheated, slowly open the first drain valve. After draining, slowly close the first drain valve, and then close the second drain valve. The purpose of this operation is to use the first drain valve to maintain that the second one can still be used to control the drain when the first one leaks. If there is an impact sound in the discharge management during discharge, the first discharge valve should be turned down until the impact sound disappears, and then slowly turned up. Discharge should not be carried out continuously to avoid affecting water circulation.
5. After the discharge is completed and the discharge valve is closed, the tightness of the discharge valve should be checked. The inspection method is to close the first discharge valve for some time, and then manually test the mold on the pipeline of the second discharge valve. If it is not cooled, there must be leakage in the discharge valve.
16、 Shutdown of furnace
1. There are generally three situations for boiler shutdown:
(1) In case of Sunday or other situations where steam is not needed in the short term, the furnace should be temporarily shut down.
(2) To clean, inspect or repair, the boiler should be completely shut down when the boiler water needs to be drained.
(3) In case of special circumstances, emergency shutdown of the furnace is necessary for safety and reliability.
The above three types of shutdowns have different requirements due to different situations. The specific explanations are as follows:
1. Temporary shutdown of the furnace.
When the boiler is operating normally and burning normally, if there is no steam needed for a short period of time or a malfunction occurs, the blower can be turned off instead of adding coal. When it is restarted, the blower can be turned on. Quickly located
If the fault cannot be resolved within 1-2 hours, it should be temporarily shut down according to the situation and the fault should be continued to be resolved.
2. Temporarily shut down the furnace
If the operation cannot be restored within 2 hours of shutdown, it is considered temporary furnace repair. The specific steps are as follows:
(1) First, close the air damper, and then turn off the blower after 5 minutes, in order to use secondary air to blow out the unburned residual gas in the furnace.
(2) 10 minutes later, open the furnace door for slag removal. When opening the furnace door, the operator should stand on the opening side to prevent flames from spraying and injuring people.
(3) After slag removal, open the upper furnace door and add coal to the furnace. The fire will not extinguish within 100 hours. When restarting, remove the slag first and then add coal. Check the water level and turn on the blower.
3. Complete shutdown:
Complete shutdown should be planned, usually every 1-3 months of operation, and attention should be paid to safety and equipment maintenance during shutdown. After following the steps for temporary shutdown, wait for the boiler water to slowly cool down to below 70 before releasing it. At this point, the safety valve must be lifted first to allow the inside of the drum to communicate with the atmosphere. If the cooling time needs to be shortened, cold water can also be introduced through the water supply pipe, and hot water can be discharged through the sewage pipe, but the water level must not be lower than the normal water level. After the boiler water enters and exits, open the manhole and hand hole and rinse the water stains with clean water.
4. Emergency shutdown:
When encountering any of the following situations during boiler operation, emergency shutdown should be taken and relevant departments should be notified.
⑴. The boiler water level is below the lowest visible edge of the water level gauge;
⑵. Continuously increasing the supply of water to the boiler and taking other measures, but the water level continues to decline;
⑶. The boiler water level exceeds the maximum visible water level (full water), but the water level cannot be seen even after draining;
⑷. All water pumps fail or the boiler water supply system malfunctions, preventing water from entering the boiler;
⑸. All water level gauges or safety valves have failed;
⑹. All pressure gauges installed in the vapor space have failed;
⑺. Damage to boiler components and endangering the safety of operating personnel;
⑻. Serious threats to the safe operation of boilers include damage to combustion equipment, collapse of furnace walls, or burning of boiler structures;
Other situations that endanger the safe operation of the boiler.
The specific steps are as follows:
A、 Turn off the blower and shake the grate handle;
B、 Quickly scoop out the coal stored in the furnace and clear out the unused coal. But it is forbidden to water the furnace.
17、 Maintenance and upkeep
1. Pay attention to the following points during the operation of the boiler:
(1) Continuously check the combustion chamber or smoke??? The accumulation of dust inside the box and the operation of supporting auxiliary equipment.
(2) There should be no standing water on the bottom floor of the boiler to prevent moisture and corrosion of the boiler base.
2. The boiler should be checked for dust accumulation inside the flue gas box every 2-3 weeks during operation.
3. The boiler should be shut down for comprehensive inspection and maintenance every 3-6 months after operation. There should be someone outside the boiler to supervise the internal inspection and maintenance of the boiler. If there are serious defects, they should be repaired in a timely manner. If the defects are not serious, they should be repaired during the next shutdown. If suspicious areas are found but do not affect safety production, records should be made for future reference. After inspection, apply boiler primer on the water surface to prevent corrosion.
4. The boiler and boiler base should be painted at least once a year.
5. There are two maintenance methods for boilers that are not used for a long time: dry and wet methods. If the boiler is shut down for more than a month, dry maintenance should be used, while wet maintenance can be used if the boiler is shut down for less than one month.
(1) Dry maintenance method:
After the boiler is shut down, drain the boiler water, cut the internal dirt to the bottom, rinse it clean, and dry it in the furnace with low heat (be careful not to use high heat). Then, install 10-30mm block shaped quicklime in separate pots and place them in the furnace drum so that the quicklime does not come into contact with metal. The weight of quicklime is calculated based on 8 kilograms per cubic meter of the drum volume. Then close all manholes, handholes, and pipeline valves, and check them every three months. If the quicklime is crushed into powder, it must be replaced immediately. When the boiler is restarted, remove the quicklime and tray.
(2) Wet maintenance method:
After the boiler is shut down, put in the discharged water to thoroughly remove the internal dirt, rinse it clean, refill with treated water until full, and heat the boiler water to 100. C， Let the gas in the water be discharged from the furnace, and then close all valves. In cold climates, wet maintenance methods should not be used to prevent boiler water from damaging the boiler.
18、 Inspection of pressure components and hydrostatic testing
1. According to the Safety Technical Supervision Regulations for Steam Boilers (96), if any of the following situations occur in the boiler, external inspection and overpressure test should be carried out on each pressure bearing component:
(1) After installation, modification, and relocation.
(2) Stop running for more than a year and need to resume operation.
(3) After major repairs to pressure components.
(4) When it is suspected that the equipment status must be checked based on the operation of the boiler.
2. The boiler should be completely shut down before inspection. Thoroughly remove internal scale and external smoke and dust, with the following key inspection points
(1) Is the weld seam of the drum normal and is there any leakage.
(2) Whether there is corrosion, grooving, deformation and other phenomena inside and outside the boiler steel plate.
(3) Whether the heating tube is deformed, and whether there are cracks at the end of the tube, the head, the gallbladder, and the weld seam.
(4) Are there any suspicious points at the connection between the water supply pipe, sewage pipe, and drum flange.
3. If the corrosion is severe, strength calculation should also be done before conducting the overpressure test.
4. The hydrostatic test pressure is 1.5 times the rated steam pressure.
5. Water pressure test steps:
(1) During the hydrostatic test, the inlet water temperature should be maintained at 20-30 degrees Celsius. Around C, if the temperature is too low, it will cause dew to condense on the outer wall of the boiler and confuse it with water seepage, making it difficult to inspect. If the temperature is too high, it will cause water droplets to evaporate and prevent leakage from being detected.
(2) After the water is full, gradually increase the pressure for a tightness check, and tighten the nuts of the flange, manhole door, and handhole cover if necessary.
(3) During the water pressure test, the water pressure should slowly rise. When the water pressure reaches the rated steam pressure of 0.4MPa, the pressure rise should be paused to check for water leakage or abnormal phenomena. Then increase the pressure to the test pressure of 0.6 MPa and maintain it for 20 minutes. If the pressure does not decrease, check when it drops to the rated steam pressure of 0.4 MPa.
(4) Any situation discovered should be recorded for repair when it drops to atmospheric pressure.
6. The hydrostatic test is considered qualified if it meets the following conditions:
(1) There are no water droplets or mist on the metal walls and welds of the pressure components.
(2) No residual deformation was found after the hydrostatic test.
7. Safety measures and precautions:
(1) During the hydrostatic test, there should be particularly clear isolation signs around the test site
Unauthorized personnel are not allowed to enter the experimental area.
(2) During the hydrostatic test, the operator shall not stand directly in front of the flange and valve.
(3) Personnel unrelated to the hydrostatic test are not allowed to stand in the test area and stop to observe.