Equipment Outline

Byproduct gas from a sealed furnace for carbide production has a dust content of about 100-200g/Nm3, and because it contains ultrafine carbon and coal dust, this gas must be cleaned, removing dust to 10g/Nm3 in order to be used as a heat source. Dust from electric furnaces conventionally has properties that make it uncollectable, leading to difficulties with dry collection methods. Instead, a wet cleaning method is used, which washes the gas with a large amount of water, leaving wastewater that causes secondary pollution from SS, CN, and PH, requiring high costs for wastewater treatment.

Equipment Characteristics

The gas generated inside the furnace is a harmful, explosive gas with high temperature and dust content, and that dust is unstable. Furthermore, due to synergy with the tar content in the gas, it is also sticky and tends to deposit, so the structure and concept behind the conventional bag filter is impractical.

Thus, the equipment we have developed to overcome the adverse conditions of sealed furnace gas has the following characteristics:

1) Structure allows for an easily maintained seal against outside air in order to work with dangerous gases. Dust is discharged without shifting, with a single discharge outlet concentrated in the device’s center and a structure that avoids the rotating slider as much as possible.
2) In order to handle hot gases, it has a special structure that moderates the concentration of heat stress caused by temperature changes.
3) It has taken successful measures against reduction of cooling effect due to dust adhering to the inner surface of the gas cooler.
4) The device is compact with a small installation space, allowing for easy operation, maintenance, and management.

A sealed furnace is cut off from the outside atmosphere by the furnace roof, and when the gas chamber surrounded by the roof reaches a state of negative pressure, air is sucked in from each seal in the roof and burns inside the furnace leading to risk of explosion or damage to the furnace roof. Further, if the gas chamber pressure exceeds the external pressure, harmful and explosive gases will escape out from the roof seals, so the amount of suction gas must be controlled in order to keep the pressure equal to atmospheric pressure.