The ratio, in weight, between air and ash used in a FLUIMAC system is around 2.5. That means that for each kg of ash, around 1.9 Normal Cubic Meters are required.

In the FLUIMAC system, there is the possibility to split the cooling process between the FLUIMAC and the Postcooler. In this case, cooling air will enter first in the Postcooler and flow from the Postcooler to FLUIMAC. The possibility to share the cooling process between these two equipments allows to better cope with the room availability.

Final temperature is more or less the same with normal air to ash ratio (2.5). But better cooling can be achieved increasing the air to ash ratio.

Air from FLUIMAC can be directed to:

The boiler via the secondary air duct. In this case, fans are needed to boost the air to the pressure of secondary air duct. Because air is hot and dusty, fans shall be designed in accordance. This solution is a little more expensive and complex than the next, but allows to recover a not negligible amount of energy and to improve the boiler efficiency.

The ECO hopper or some point at a negative pressure in the flue gas path. This solution is simple and not expensive. As it adds some air to the flue gas amount, it is applicable where the flue gas system has some margin.

To the ambient. In this case an exhausting system (filter + fan) is required.

Yes, up to a certain extent. Maximum recommended slope of a FLUIMAC is 15°.

The height necessary to arrange a FLUIMAC under a FBC boiler comes from the height of the FLUIMAC itself (around 2.5 meters, inclusive of the expansion joint) plus the drain pipe minimum height to ensure the sealing against the pressure of the furnace (1 meter starting from the primary air distribution plate.

To recovery the heat transferred from the ash to the cooling air, the best way is to utilize the cooling air as combustion air. Then the system configuration where the cooling air is boosted by a fan to the secondary air duct is suggested, like shown in the first figure. It is convenient to note that secondary air through the Air Heater will be a little less because of the subtraction of the FLUIMAC cooling air, and that requires the Air Heater to be designed accordingly.
The heat recovery is also possible in the configuration where cooling air from FLUIMAC is directed to the ECO hopper, as in the second figure. In this case the recovery is indirect in the sense that the FLUIMAC cooling air (after joining with the flue gas) will transfer the heat to the combustion air and in turn to the furnace. Also in this case the Air Heater operation is affected by the additional air from FLUIMAC and that has to be considered in the evaluation.

That heat recovery can be easily calculated case by case. As a typical figure, we can assume a FLUIMAC where 6 t/h of ash are cooled from 850°C down to 200°C. For such a case, around 15 t/h of air will be heated from ambient temperature (16 °C) to 250 °C, with 980 kW heat transfer from the ash to the air and then to the furnace.

The Superbelt, like in all the Magaldi conveyors, is the hearth of the FLUIMAC system and it is the only moving part of the system. Wearing of the Superbelt is very, very low because:

The belt speed is extremely low and therefore the wearing is negligible.

There is no relative motion between the belt (running) and the ash (conveyed by the pans of the belt) and hence there is no wearing due to the friction between ash and belt.

Superbelt used in MAC systems has shown an average life of more than 10 years; Superbelt in a FLUIMAC system is expected to have even a longer life becase of the less severe operating conditions. Guaranteed life is 5 years.

Air leaving the FLUIMAC is dusty air, and cannot be otherwise. Average particulate content is around 3 grams/Normal Cubic Meter.