| 摘要 |
The invention relates to a water-tube boiler, the firing of which is converted from oil or gas to coal dust. The main aim of the invention is that the nominal steam generating capacity of the boiler and the steam states (pressure, superheating temperature) at the boiler outlet are the same after the conversion as before the firing conversion. In order to take into account the requirements for lower combustion chamber loading and reduced flue gas speed in the contact heating surfaces, and in order to allow for the greater flue gas quantity in the case of coal dust firing, the original oil or gas-fired water-tube boiler is equipped with one or more precombustion chambers and one or more downstream heating surface blocks. Moreover, to reduce fly ash accumulation in the combustion chamber, a deflector plate for the flames is arranged in it and tertiary air nozzles are arranged at the combustion chamber front wall. The firing conversion proposed here can be carried out with careful planning and preparation on medium-sized boilers during a summer period. <IMAGE>
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