What do fixed-row and continuous-row mean?

It is best to carry out blowdown on a daily basis during low-load night shifts; it is not necessary to do so just to meet certain metrics. Blowdown helps remove the sediment that forms due to the addition of chemicals, so it is very important. Performing blowdown at low load levels helps prevent issues with the water level in the steam drum. However, with large-capacity boilers, the requirements for water treatment are quite high, and these systems can meet the boiler’s requirements regarding water quality, making blowdown unnecessary in such cases

Continuous discharge constitutes a type of surface discharge; it involves removing the boiler water with a high salt concentration from the water surface, thereby keeping the salt content of the boiler water within acceptable limits. This helps to reduce boiler water expansion and foaming, as well as the humidity and salt content of the steam, and it can also minimize scaling inside the evaporation tubes； Regular sludge discharge is mainly to remove the sediment formed by hardness salts in the water after chemical addition.

Boiler blowdown is generally carried out every 8 hours, for 15–30 seconds at a time or as required; continuous blowdown means ongoing discharge, with the amount of discharge controlled by the valve opening.

According to the JB/T10354-2002 regulations for the operation of industrial boilers, the frequency of slag removal is determined manually based on the conditions of the boiler itself. The requirements for regular slag removal are as follows: a) Slag removal should be carried out when the boiler is shut down or operating at low load, and it should be done in short intervals; b) Before slag removal, the boiler’s water level should be adjusted to be close to the upper limit of the normal range, and the water level must be closely monitored during this process to prevent the boiler from running out of water; c) Those who operate the slag removal valve should, if they cannot directly see the water level indicated by the gauge, Discharge should be carried out in conjunction with the personnel monitoring the water level gauge; d) Discharge must be performed every eight hours. If multiple boilers share a single drain main, and there are no check valves on the drain pipes of each boiler, simultaneous draining is prohibited: e) No other operations should be carried out while draining; if such operations are necessary, draining must be stopped first: f) When draining, open the slow-opening valve that is closer to the boiler first, and then intermittently open and close the fast-opening valve that is further away from the boiler in order to achieve rapid drainage. After shutting off the drainage, first close the quick-opening valve, then the slow-opening valve; afterward, slightly open the quick-opening valve to drain any remaining water before closing it. g) Once the drainage operation is complete, after closing the drainage valve, check the outlet of the drainage pipe to ensure there are no leaks. Continuous blowdown is determined based on the water quality in the boiler’s drum. It is specified that when the boiler reaches 70% of its rated load and the water level is normal, the automatic adjustment devices for feedwater and combustion should be activated; the continuous blowdown valve should be adjusted promptly according to the results of water quality tests. The blowdown of steam boilers should ensure that the alkalinity and salt content of the boiler water remain within specified limits ； The blowdown of hot water boilers must ensure that the quality of the outlet water meets the requirements.

What was said on the 3rd floor is very correct; whether it’s fixed or continuous circulation, it’s all done to ensure the quality of the water in the boiler.

Our company has the following rules regarding scheduled and continuous discharge: for scheduled discharge, the number of times waste water is discharged per shift is determined based on the water quality conditions, but discharge must take place at least once per shift. The following points should be noted when scheduling regular drainage: a. The fully open time of the drain valves should not exceed 30 seconds, and the drainage time for one set of drain valves should not exceed 1 minute; b. When carrying out regular drainage, one set of valves should be opened first – the valve should be opened once initially, followed by a second opening ； To stop discharging wastewater, the sequence of operations is reversed: first close the secondary valve, then close the primary valve; afterward open the secondary valve to drain the water between the primary and secondary valves, and finally close it ； c. Regular blowdown is not allowed when the drum level is low (30 mm below the normal level) ； d. Discharging waste under high load is strictly prohibited. Keep it slightly open for an extended period.

Continuous discharge constitutes a type of surface discharge; it involves removing the boiler water with a high salt concentration from the water surface, thereby keeping the salt content of the boiler water within acceptable limits. This helps to reduce boiler water expansion and foaming, as well as the humidity and salt content of the steam, and it can also minimize scaling inside the evaporation tubes； Regular sludge discharge is mainly to remove the sediment formed by hardness salts in the water after chemical addition. The sewage discharge time is determined based on the results of water quality tests. The scheduled discharge usually takes place every 8 hours.

The person upstairs mentioned a lot about the functions related to fixed exhaust systems, and their explanation was quite comprehensive. So, the original poster might want to pay attention to the installation location of the boiler’s fixed exhaust systems. The fixed exhaust system is installed near the steam drum and is used for regular drainage from the steam drum, while the exhaust system is located on the ground floor. The structure of this equipment is relatively simple; it belongs to the category of tank-type devices. When designing it, it is necessary to consider the placement of exhaust vents, taking into account the safety of the equipment

Continuous drainage constitutes a form of surface drainage; it involves discharging boiler water with a high salt concentration from the water surface, thereby keeping the salt content of the boiler water within acceptable limits. This helps to reduce boiler water expansion and foaming, as well as the humidity and salt content of the steam. It also helps to minimize scaling in the evaporation tubes. Generally, the drainage rate is adjusted so that continuous drainage occurs, and the water flows into a continuous drainage expansion tank. The heat energy contained in this water can be utilized by a heat exchanger to preheat the deionized water before it enters the deaerator, after which it is discharged through a regular drainage expansion tank. Regular slag discharge is usually carried out at the bottom of the boiler or in the lower header of the water wall, with the aim of removing impurities. It is typically done once per shift, but attention must be paid to the water level and load. At the same time, it can also be used to appropriately activate fixed drainage during the early stage of boiler startup, when the water circulation has not yet been fully established; this helps to promote the establishment of water circulation in the water wall, ensures that the tubes in the boiler’s water wall are not subjected to localized heating, and thus serves to protect the water wall.

Boiler blowdown 1 Precautions for boiler blowdown 1 To ensure that the quality of steam and water meets the specifications and requirements set out in the \"Quality Standards for Water and Steam in Thermal Power Generation Units and Steam Power Equipment,\" it is necessary to carry out boiler blowdown. The discharge pipeline should be warmed up before discharging waste, to prevent water hammer. Before setting the discharge rate, increase the drum water level appropriately. Drainage should be carried out circuit by circuit; it is generally not allowed to have two or more drainage points operating simultaneously in order to maintain a relatively stable drum water level and ensure the safety of the water circulation. Discharge should be carried out when the load is stable, and the discharge rate should be as fast as possible ； 2 During normal operation, the opening degree of the control valve and the blowdown timing should be adjusted as appropriate, based on the requirements for steam and water quality control as well as the test results, in order to carry out continuous blowdown ； 3 When the boiler is not operating properly or an accident occurs (except for a water-overflow accident), or when there is a malfunction in the blowdown system, etc., blowdown must be stopped immediately.

Continuous discharge constitutes surface discharge, involving the release of boiler water with a high salt concentration at the surface, thereby keeping the salt content of the boiler water within acceptable limits； Regular sludge discharge is mainly to remove the sediment formed by hardness salts in the water after chemical addition.

Continuous discharge constitutes surface discharge, involving the release of boiler water with a high salt concentration on the water surface, while periodic discharge is primarily used to remove the sediments formed by hardness salts resulting from the addition of chemicals to the water.

Waste discharge: The slag present in the boiler water, along with accumulated salts and other impurities, is discharged in appropriate amounts to ensure the quality of the boiler water. The purpose of regular sewage discharge is to remove the sludge at the bottom of the steam drum and waste boilers, preventing this sludge from blocking the pipelines. Regular drainage can also remove some of the boiler water with a high concentration of dissolved solids from inside the furnace, thereby reducing the salt and alkali content in the boiler water and ensuring that its quality remains satisfactory. Periodic discharge is also known as intermittent discharge. The characteristic of periodic sewage discharge is a short duration and high flow rate, so that the sediments can be carried away by the rapidly flowing boiler water. The interval and amount of regular blowdown depend on the dosage of chemicals added to the boiler water, the degree of turbidity of the boiler water and test results, as well as the quality of the feed water. Generally, the wastewater discharge does not exceed 5% of the water supply volume. It is best to carry out this operation when the steam load is low. Before discharge, the liquid level should be kept 30–50 mm higher than the normal level, and the accuracy of the level gauge should also be checked. During discharge, monitor the changes in the liquid level gauge while controlling the discharge. The regular sewage outlet is located at the lowest point of the boiler, where dissolved solids and sediments accumulate. The procedure for regular sewage discharge is as follows: first open the second valve, then slightly open the first valve for a while, and finally fully open the first valve. After the discharge is complete, close the first valve first, then the second valve. Note: Sludge discharge should be carried out at a high water level, and the amount of sludge discharged should be such that the quality of the boiler water remains satisfactory. Continuous discharge: Continuous discharge involves using surface drain pipes located within the drum to continuously remove boiler water with high salt and alkali concentrations from the boiler, thereby reducing the salt and alkali levels in the boiler water and ensuring the quality of the steam. Continuous discharge is also known as surface discharge. The collector pipe for continuous drainage is located about 80 mm below the steam-water interface in the drum; this is precisely the area where steam is released, and it is the spot with the highest salt concentration in the boiler water. By draining a portion of this boiler water continuously from here, it is possible to keep the salt content in the boiler water as well as the salt content in the steam within specified limits.

Fixed discharge: Regular sewage discharge; Continuous discharge: Continuous sewage discharge