When reforming coal-fired boilers, the first thing we need to pay attention to is that the capacity of oil-fired boilers is relatively small. It is better to adopt the combustion mode of micro-positive pressure. The integrated burner is often used, on the one hand, the price is relatively low, on the other hand, the reconstruction construction is relatively easy. It can ensure safe and efficient operation.
Small coal-fired boilers need to choose burners according to the shape of the furnace when they are reformed to fuel oil and gas. Commonly used are ring, exhaust pipe or hearth type natural draft diffuser or atmospheric burner. The burner has simple structure and does not need blower. It is suitable for low-pressure gas in general civil gas pipeline network and is relatively safe.
The disadvantage is that the combustion efficiency is relatively low, and the design has a great influence on the combustion efficiency of the burner.
Attention should be paid to the following problems: the position of the vent should be under the burner, and the furnace above the burner should be sealed as far as possible. The chimney needs to add air regulating valve to improve combustion efficiency by controlling wind intensity to adjust air coefficient.
When the coal-fired boilers below 10T are reformed with gas, they usually choose the combustion mode of micro-positive pressure, and use higher one-time reformation cost to reduce the later operation cost.
The SZL and DZL water-pipe boilers are best equipped with an integrated burner. In the process of renovation, the back arches of SZL and DZL water tube boilers need to be removed. The back wall and the upper and lower header of the back arch pipe can be stretched to be the back wall pipe, and the part of the back arch pipe which enters the inner part of the pot drum from the middle needs to be removed.
At present, there are many kinds of all-in-one fully automatic gas burners at home and abroad, and there is little difference in combustion performance and control level. Selection can be made according to the type of fuel applicable, whether backpressure is available or not, valve assembly and other aspects. Because of the large price difference, it is necessary to be realistic when making choices.
SHL and DHL boilers generally have a small distance between the front and rear walls, so they can not meet the requirements of flame length combustion of an integrated burner. In addition to removing the grate, the burner installation elevation should be placed below the back arch, so that the flame can be placed in a lower return type.
Another modification method is to adopt a furnace bed diffusive or atmospheric burner, which is installed on the grate bracket (to remove grate sheets), and forced ventilation by using the air supply system. When micro-positive pressure combustion occurs, both the air pressure of blower and the gas supply pressure need to be increased correspondingly, but the integrated burner layout from bottom to top is not advisable.
Attention is needed:The investment of split burner with adjustable air regulator blades is relatively large.
The split burner with adjustable air regulator blades can be used in the retrofitting of large capacity coal-fired water pipe boilers above 10T. The self-designed dispersive burners can also be used, but the micro-barotropic combustion mode is still used. In order to ensure the combustion efficiency and safety of the boiler, it is better to equip the imported gas valve group and the full automatic control system of Wuxi ZOZEN boiler.
Attention is needed: The grate in the combustion space is not necessarily removed during the retrofit of the water pipe boiler, but can also be treated by covering the grate surface with heat insulation and refractory layer.
Above are the problems that should be paid attention to in the transformation of coal-fired boilers, which can be divided into small and medium-sized boilers below 10T and large-scale boilers above 10T. The specific coal-fired boiler transformation still needs to refer to the specific recommendations of manufacturers to implement.
