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Short-answer questions. 1. When the boiler load changes, what are the reasons for the changes in the drum water level? Answer: There are two reasons why changes in boiler load lead to changes in the drum water level. One is the disruption of the balance between the water supply and evaporation rates, and the other is that changes in load inevitably cause pressure changes, which in turn result in changes in the specific volume of the working fluid. 2. What are the purposes of regular and continuous blowdown in boilers? Answer: The purpose is to remove impurities from the boiler water in order to ensure its quality ； The regular drainage of the boiler is used to remove impurities and sediment from the boiler water; therefore, it should be connected at the lowest point of the evaporation system, usually at the lowest point of the lower header or downcomer of the drum ； The series arrangement is used to remove water with a high salt content from the boiler water, and it is generally located at the lower part of the drum. Fixed drainage also serves to enhance water circulation and reduce thermal gradients. 3. What principles are utilized in the operation of the steam-water separation device inside the boiler drum? Answer: The working principles of the steam-water separation device are as follows: First, it utilizes the principle of inertia to separate steam from water ； The second method is to use the principle of centrifugal force for steam and water separation ； Third, steam and water separation is achieved by utilizing the principle of adhesion. 4. Why is it still necessary to control the pressure increase rate during the later stages of boiler startup? Answer: (1) Although the temperature difference between the upper and lower walls of the steam drum gradually decreases at this time, due to the relatively thick walls of the drum, the temperature difference between the inner and outer walls remains significant; it may even increase ； ⑵Additionally, at the onset of operation, the drum is subjected to stresses close to the operating pressure. Therefore, it is still necessary to control the rate of pressure increase in the later stages to prevent an increase in stress on the drum wall. 5. What is the function of the ash discharge pipe at the lower part of the economizer? The ash hopper located at the lower part of the flue in the tail shaft collects a portion of the fly ash that separates from the flue gas due to gravity. This ash is then discharged into the ash trough via an ash pipe, thereby reducing the dust content in the flue gas and minimizing the risk of fouling in the preheater. Moreover, when a leakage occurs in the economizer, some of the water can be drained, thereby reducing the ash buildup on the heating surfaces of the air preheater. 6. What are the functions of a header? In the layout of the heating surfaces, the header serves to collect, mix, and distribute the working fluid, acting as the connecting hub for the arrangement of these heating surfaces (8 points). Additionally, some header tanks are also used to suspend the heating surfaces, and to install drain or sewage discharge devices. 7. How to flush the water level gauge? The sequence for flushing the water level gauge in the boiler drum is 2500 mm (adjustable); the ammonia preparation system stops automatically. 2) Close the pneumatic isolation valve on the liquid ammonia pipeline. 3) Shut down the demineralized water transfer pump. 180. Preparatory work before putting the boiler gas system into operation? 1. The pipeline tightness test for the fuel gas system has been passed; there are no leaks. 2. The valves at various locations (ball valves, pressure regulators, safety shut-off valves, globe valves, vent valves) operate smoothly and reliably, and seal tightly when closed. 3 Local and remote meters are in good condition and in operation. A isolation blind plate should be installed before the gas system of the 4th standby boiler to prevent gas leakage from the valves from entering the furnace. 181. What are the precautions for starting and stopping the boiler gas system? 1 After starting the furnace, wait until the oil gun is removed and combustion becomes stable before introducing gas. During shutdown, the gas system should be shut down first before reducing the boiler’s load, and blind flanges should be installed. When operating the 2-gas system, the operator must wear a portable gas detector, and another person must be assigned to supervise. 182. What are the inspection items during the operation of the boiler coal bunker unclogging machine? 1. Check that all mechanical components are operating without jamming, abnormal noises, or overheating. Check whether the motor is overheating or overflowing. 3 Check whether coal is being discharged properly before starting the block clearing machine. 4. Check all welded areas and flange connections in the coal bin for any air or powder leaks. 5 The swivel bearing should be lubricated every 100 hours of operation. 183. What conditions must be met for boilers to operate in parallel? The boiler is operating normally with stable combustion. 1) The steam pressure at the boiler outlet is 0.05–0.06 MPa lower than the main pipe pressure. 2) The difference between the steam temperature at the boiler outlet and the steam temperature in the main pipe must be less than 50°C. 3) The drum water level is around -50 mm. 4) The steam quality meets the quality standards. 184. What are the principles of coal transfer interlock? Principle 1: During operation, if a device fails and shuts down, the interlock mechanism will immediately stop all devices between that faulty device and the reciprocating feeder (including the reciprocating feeder itself), with the exception of the crusher. Principle 2: If the coal crusher fails and shuts down, the belt conveyor in Section 1 will also shut down as a result of the interlock. 185. What is the startup sequence for the equipment in the coal conveying system? Boiler side (A): Boiler horizontal belt → Boiler section inclined belt → Boiler side crusher → Boiler section 1 belt → Boiler side reciprocating coal feeder. Gasification side (B): Gasification side horizontal belt → Gasification section inclined belt → Gasification side crusher → Gasification section 1 belt → Gasification side reciprocating coal feeder. 186. What are the steps to start the coal conveyor belt? 1. Connect power to the control cabinet; check if the power indicator lights up. 2 Press the coal conveyor belt start button; the start indicator light comes on, and the motor that drives the conveyor belt rollers begins to rotate. The 3 drive roller motors drive the main roller to rotate, and the belt conveyor begins to operate. 187. What are the startup steps for a coal crusher? 1. Connect power to the coal crusher control cabinet; the power indicator light turns on. 2. First, press the start button for the motor of the slow roller in the coal crusher; the motor will then start. Pay attention to the current reading on the ammeter connected to the slow roller motor. If the current suddenly increases, immediately press the stop button and determine the cause. 3 Then press the fast roller motor start button, and the fast roller motor will start. 4 After the coal crusher is started, it should run idle for a few minutes first; feeding material can only be begun once the working toothed roller reaches its rated operating speed. 188. What are the steps to stop the crusher? 1 Check that the coal inside the roller screen of a belt conveyor has been completely removed. 2 First, press the “Stop” button for the fast roller; the indicator light will turn on ； Stop the fast roller. 3 Press the “Stop” button on the slow roller; the indicator light will turn on, stopping the fast roller ； The crusher has stopped. 189. What are the inspection items before starting the coal plow? 1. The push rod foot bolts and bracket fixing bolts should be complete and free from looseness. 2 The coal-unloading iron plate or rubber sheet should be intact, without excessive wear, and in proper alignment with the belt. 3 Check that there is no sticking in the mechanical transmission part. 4 Check that the upward and downward limit switches are in good condition, and that the motor wiring is intact. Before starting the 5 coal conveyor belt, the coal plow must be in a non-operational state. 190. Emergency shutdown procedure for the coal conveying system? 1 Directly pull the local emergency stop pull-cord switch ； 2 Immediately notify the coal yard to stop conveying coal into the upper coal hopper ； 3 Notify the on-duty shift leader and immediately investigate the cause of the emergency stop device malfunction. 191. Describe the process flow of the produced water treatment system? The raw water undergoes heat exchange with condensate in a plate heat exchanger, resulting in a temperature of 34–37°C. It then enters a steam-water heat exchanger where it exchanges heat with low-pressure steam, reaching a temperature of 40–42°C. After that, it passes through an activated carbon filter; following treatment by this filter, the water goes into a clean water tank. A clean water pump then transports the pre-treated water to a cation exchange resin for further treatment. After carbon removal, the water enters an intermediate water tank, and an intermediate water pump sends this water to an anion exchange resin and a mixed ion exchange resin. The resulting desalinated water goes into a desalination tank, and a desalination pump transports it outside for use in the boiler system and various process units throughout the plant. Ammonia is added to this water before it is used in those systems. 192. Describe the process flow of condensate purification? The condensate is collected in the condensate tank and pumped by a condensate pump to a plate heat exchanger where it exchanges heat with the water used in production. After this heat exchange, the liquid passes through a tubular precision porous filter. The filtered condensate is then sent to a refined mixed ion exchanger for further treatment, after which it is delivered to the desalination tank. 193. What is the process flow of a reverse osmosis wastewater treatment system? The wastewater in the neutralization tank is pumped by a sewage pump to the 1501# reverse osmosis wastewater treatment system and its water tank. From there, it is sent to multi-media filters and activated carbon filters for filtration. It then passes through a plate heat exchanger to exchange heat with low-pressure steam, thereby heating the neutralized water to 25°C. After that, it goes through a safety filter for further purification. Finally, a high-pressure pump is used to boost the pressure of the neutralized water and send it to the RO reverse osmosis treatment unit. The treated clean water is discharged, while the concentrated brine is collected in a concentration tank and sent to the coal yard for use in dust suppression. 194. How to operate an activated carbon filter? The operator contacts the dispatcher regarding the consumption of process water. After the operator verifies that the system is in order, they test the turbidity at the filter inlet for analytical purposes. 1) When the turbidity at the filter inlet is ≤7mg/L, open the inlet door and the drain door. 2) When the turbidity at the discharge outlet of the test filter is ≤ 3 mg/L, open the outlet valve, close the discharge valve, and adjust the flow rate to supply water to the clean water tank. 3) Check the operation of the filter; if any abnormalities are detected, report to the shift leader. 195. What are the inspection items before starting the anion bed? 1) The valves in the anion bed process pipelines have not been overhauled, but have passed the calibration ； 2) The pressure test of the cation bed pipeline passed ； 3) The equipment instruments are in good condition and have passed calibration ； 4) The equipment surface is undamaged, and the anti-corrosion paint is in good condition ； 5) The regeneration system is equipped with ； 196. What are the steps to put the anion bed into operation? 1) Start the clean water pump to supply water to the anion exchange bed ； 2) Open the cation bed inlet door and air discharge door ； 3) Once water is detected at the exhaust valve, close the inlet valve and the exhaust valve ； 4) Pre-commissioning wash: Open the wash drain valve and inlet valve of the cation exchange resin bed; if the effluent is colorless and the Na+ concentration is less than 100µg/L, the wash is successful, and water can be supplied to the intermediate water tank. 197. What are the steps to put the anion bed into operation? 1) Start the intermediate water pump to supply water to the anion bed ； 2) Open the inlet door and air discharge door of the anion bed ； 3) Once water is detected at the exhaust valve, close the inlet valve and the exhaust valve ； 4) Pre-commissioning rinsing: Open the forward flushing drain valve and inlet valve of the cation exchange resin bed. If the effluent is colorless, has a conductivity of less than 5µs/cm, and a silica content of less than 100ug/L, then the rinsing is successful and water can be supplied to the mixed-bed resin bed. 198. Startup of the waste steam recovery system? 1. Upon receiving instructions from the shift supervisor, start the waste steam recovery feed pump. 2 Open the pump’s inlet valve and vent the air from the pump body. 3 Press the local start button, and check whether the pressure gauge and current are normal ； ) 4 Once the standby pump is running stably, open the outlet valve and adjust the flow rate to supply water to the waste steam recovery unit at the 24-meter level of the boiler. 5. During operation, conduct regular inspections of the pump motor’s temperature, motor current, and pump outlet pressure. If any abnormalities are detected, identify the cause immediately and take action to address it. 199. What are the startup steps for a mixed-bed? 1) Open the drain valve, air valve, and inlet valve of the mixed-bed regeneration system; adjust the inlet flow rate to above 100 t/h, and close the air valve once water starts flowing from it ； 2) Perform forward flushing for about 20 minutes. After testing, if the conductivity of the effluent is less than 0.2 µs/cm, open the outlet valve of the mixed bed and close the forward drain valve to put it into operation. 200. What are the steps to shut down a mixed-bed system? 1) Close the mixed-bed outlet valve and open the forward wash drain valve ； 2) Close the sampling tube and conductivity meter door ； 3) For mixed beds requiring maintenance, the inlet and outlet primary valves must be closed ； 4) Stop the desalination water pump according to external water supply requirements.