Rear arch detachment, repair

It’s a chain grate furnace, I’ve encountered this type of furnace before; the rear arch is the ignition arch located behind the chain grate. Its function, in addition to serving to seal/isolate the furnace wall, is mainly to absorb radiant heat, thereby heating and igniting the coal in the latter part of the grate. The rear arch furnace walls usually have insulation/heat-insulating layers as well as refractory layers; even if the insulation layer comes off, the refractory layer remains, and its strength is generally higher than that of the insulation layer. Once the rear arch (insulation layer and fire-resistant layer) is completely removed, the convective tube bank becomes exposed, resulting in a short circuit between the furnace and the flue gases of the convective tube bank. This leads to a significant reduction in the boiler’s efficiency. As the negative pressure in the flue increases further downstream in the boiler, the flow rate of flue gases passing through a hole of 1 square meter becomes very high due to this short circuit. Therefore, it is recommended that the original poster handle it as soon as possible.