Holnam, Inc. has a unique relationship with the Alabama Power's Miller generating station near Birmingham, Alabama, USA. Holnam recovers and stores fly ash generated at the plant and operates a barge load-out facility to distribute the material.

The station supplies electric power to the city of Birmingham and the surrounding areas. The plant consists of four boiler units all using coal from the Powder River Basin. The fly ash being recovered by Holnam is from boiler units 3 and 4.

The fly ash is taken from the precipitators by a Nash vacuum system and accumulated into two 150-ton storage silos. The material is then pneumatically conveyed to two 1,500-ton truck/barge load-out silos located more than 2,300 ft (700 meters) away. A MODCO dual-pod conveyor is used to move material at 80 to 100 tph through a convey line that starts at 8-in. (200-mm) diameter and changes to 10-in. (250-mm) diameter at about half the distance to the barge facility.

The pod conveyor vessels incorporate sliding disc-type valves, which are said to be a better investment for systems operating at pressures greater than 15 psi (10,547 kg/m[superscript]2). The conveyor is supported by a two-stage blower package rated at 2,750 cfm (78 m3/min) at 35 psi (24,609 kg/m2) with 400 connected horsepower (298 kW). However, the system routinely conveys at its rated capacity using 22 to 25 psi of the available pressure, requiring only 275 hp (205 kW) for routine operation.

The system includes a local motor control center/control panel and a remote operating station at the barge facility. MODCO supplied the control valves and air gravity conveyors to transport fly ash from the storage silos to the dual-pod conveyor.

While the fly ash facility is located on Alabama Power property, it was built by Holnam and put into operation in September 1997. Holnam currently distributes fly ash by truck throughout the southeastern United States; barge distribution via the Warrior-Tombigbee waterway is scheduled to be in operation in early 1999.

Current production capacity from units 3 and 4 is 220,000 tpy, and this number is expected to double when units 1 and 2 come on stream in the near future.