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“Air and flue gas system”- related faq

  • How to deal with too much damage of the dust collecting cloth bag of the biomass-fired boiler? 2018-07-12
    Question details (Performance):Dust collecting cloth bag damages a lot. Answer: The cause of the problem: As the biomass-fired boiler fuel moisture is high, and bag material is general PPS, which will reduce the base fabric of the bag in the case of high temperature, high humidity, hydrolysis, oxidation, and cause damage; In addition, the fuel moisture is high and it cannot be completely burned in the furnace, so it burns in the dust collector, which is also an important reason for the damage of the cloth bag.Troubleshooting:(1) Design by full consideration of high fuel moisture, choosing the appropriate induced draft fan, if the existing design is not enough then consider change the induced draft fan.(2) If induced air volume is sufficient, a proper distribution of the first and second wind should be considered. Generally, the fuel with high moisture and light quality such as wood chips, straw and wheat straw hood, the secondary air volume should be increased. For bark, miscellaneous
  • What if combustion of biomass fuel boiler is not sufficient? 2018-07-12
    Question details (Specific performance):Biomass environmental protection and energy saving fuel made of straw and livestock etc., their combustion is not full. Answer: The cause of the problem:1. Air quantity is insufficient or too big.2. Outer flame position is not proper.Troubleshooting:1.Sufficient temperature: sufficient combustion of biomass boiler needs high temperature, combustion rate is proportional to the temperature, to raise the temperature as much as possible but guarantee there is no slagging.2. Proper air volume. If the air volume is too large, it will reduce the temperature of the furnace and increase the incomplete combustion of fuel. If the air volume is insufficient, the combustion efficiency will be reduced, and the waste of fuel will also increase the emission of smoke.3. Sufficient mixing of fuel and air. During the burning stage of biomass boilers, the sufficient mixing of air and fuel should be ensured and the disturbance should be strengthened during the burnin
  • How to solve the problem of coking in circulating fluidized bed boiler operation? 2018-07-12
    (Question Details) Specific Performance:(1) The bed temperature has risen sharply.(2) The oxygen level drops even to zero.(3) The current of the primary blower is reduced, and the wind pressure in the wind chamber is high and fluctuates.(4) The furnace negative pressure increases and the induced draft fan current decreases.(5) Difficulties in slagging.(6) If coking in low temperature, the bed temperature, bed pressure distribution is uneven, the deviation is too large, the bed pressure, the plenum pressure, the bed temperature is not normal, and the local bed temperature measurement point is not normally raised or lowered.(7) The bed pressure indicator value fluctuates little. Answer: causes of failure :(1) Improper operation, resulting in overheated bed temperature and coking.(2) The primary air volume during operation is kept too small, which is lower than the minimum fluidized air volume, so that the material can’t be well fluidized but piled up, the temperature field of the entire
  • Why the slag discharge tube of circulating fluidized bed boiler will be blocked? 2018-07-12
    (Details on the problem) Specific Performance:Slagging pipe blocks during operation of circulating fluidized bed boiler. Answer:cause of failure:(1) The internal shape is caused by the limited expansion of the wear-resistant material inside the slag discharge pipe. The internal components of the slag cooler are deformed, affecting the fluidization of the slag cooler; the slag cooler is deactivated for a long time or a single slag cooler is selected for slagging, and the bed material in the deactivated slag cooler is bonded under the influence of steam, which being low temperature coke.(2) The operating personnel did not grasp the ratio of the fluidized air volume of the slag cooler. Inappropriate air volume ratio resulted in poor ash slag fluidization in the slag cooler. Troubleshooting:(1) Operation personnel should strengthen understanding of boiler operating conditions, adjust boiler parameters in a timely manner, set up the concept of boiler material dynamic balance, control boiler
  • Why are there percussive sounds and vibrations in the boiler drum or pipe of a coal-fired boiler? (water impact) 2018-07-12
    Question details (Performance):The steam pipe vibrates violently and has a dull impact sound.Answer:  fault reason: There is air in pipeline  ; automatic air vent valve is not turned on; or it is out of order. Troubleshooting: Check all the air release valves on the water supply pipe and the air release valves on the top of the boiler tube for gas storage. If the valve fails, it should be replaced immediately.
  • What causes the fan bearing to vibrate during boiler operation? 2018-07-12
    Question details (Performance):1. High temperature of motor, fast temperature rise.2. Overload, high outlet pressure and frequent safety valve open often.3. The vibration is intensified, the side vibration of the fan motor coupling is large, and the fan body never vibrates to vibration.4. No obvious vibration was found in no-load test of fan motor. Answer:  Fault reason:Fan bearing vibration is common fault in the operation, the vibration of the fan will cause damage of bearing and blade, bolt looseness, chassis and wind damage, fan vibration rises abruptly in the operation. this is because when the gas enter impeller and the rotating blade working face has certain angle, according to the principle of fluid mechanics, gas from non-working face must be a spiral blade, so the dust particles in the gas will slowly sedimentation due to vortex. Airfoil blades are very easy to accumulate dust. When the accumulated ash reaches a certain weight, a part of the large amount of accumulated ash wi
  • What is the reason for the failure of the coal economizer pipe of the coal-fired boiler? 2018-07-12
    Question details (Performance):1. The furnace wall at the coal economizer leaks water and steam with abnormal sound.2. The water level in the boiler drops sharply, and the water supply is obviously greater than the evaporation capacity.3. Smoke exhaust temperature and water outlet temperature rise.Answer: Fault reason:1. The water quality does not reach standard, and the oxygen in the water is decomposed into corroded pipe walls when the temperature rises.2. The low feed water temperature and smoke exhaust temperature make the inner and outer wall of the coal economizer pipe produce acid corrosion, or flying ash wear the pipe wall thin. 3. The pipe is blocked by impurities, causing overheating.4. Poor materials, defects in manufacturing, installation and maintenance. Troubleshooting:1. When economizer is slightly broke, it still maintains boiler operation, and the gap seems will not expand rapidly, in this case, load operation should be reduced, and start the spare boiler immediately,
  • What is the reason for pump in the gas-fired boiler does not transfer oil? 2018-07-12
    Question details (performance):A pump in a gas boiler does not transfer oil. Answer: Fault reason:(1) Pump failure.(2) Oil pressure and power are reduced.(3) The oil inlet valve is not sealed.(4) The inlet pipe is not sealed.(5) The interceptor valve is closed.(6) The filter is contaminated.(7) The filter is not sealed.(8) The tubing is not sealed.(9) Pump suck air inlet.(10) The vacuum degree in oil tube is too high.Troubleshooting:(1) Replace with new pump.(2) Remove the inlet valve and clean or replace it.(3) Seal the inlet pipe.(4) Open.(5) Cleaning.(6) Replace the sealing ring.(7) Tighten and exhaust.(8) Clean the filter and valve.