Perforated floors

Hargreaves-Robinson A process for making sodium sulfate and hydrochloric acid by passing a mixture of wet sulfur dioxide and air through a series of vertical chambers containing briquettes of salt lying on a perforated floor, the temperature being maintained at approximately 500°C. 

A liquid level is maintained with an overflow weir while the vapor comes up through the perforated floor at sufficient velocity to keep most of the liquid from weeping through. Hole sizes may range from 1/8 to lin., but are mostly l/4-l/2in. Hole area as a... 

The application of forced airflow is necessary for drying products in static beds, which form a comparatively large flow resistance in the bed. Such products include grains and hay. One solution is to build a solar room dryer [13] as shown in Figure 14.7a. The grains to be dried are placed as a bed 1 on a perforated flooring. Collectors 2 are located on the southern wall and the roof of the building. The air warmed... 

One variation of the batch-in-bin process is to use alternate heating and cooling cycles. This reduces the moisture differential between the drier grain near the perforated floor and the damper grain near the top of the grain column. 

A heater fen unit is installed below the perforated floor that blows warm air up through the grain. 

Dryers suitable for drying of the biomass include batch through-circulation dryer (perforated floor bin dryer), PMB or continuous through-circulation dryer, direct rotary dryer (rotary cascade dryer), indirect rotary dryer (steam-tube rotary dryer), fluidized bed dryer (pressurized steam fluid bed dryer), and pneumatic conveying dryer (flash dryer) (Amos 1998 Brammer and Bridgwater, 1999 Wimmerstedt, 2006 Roos, 2008). Drying media can be flue gas, hot air, or superheated steam. 

Holes (in electrical conductivity). The absence of an electron from a compound or crystal structure leaves a hole. Holes move through the crystal or compound under the action of an electric field, in the opposite direction to that taken by electrons. They thus behave much like electrons, but carrying positive charge. Holey Boy. A type of perforated floor in intermittent downdraught kilns firing salt-glazed pipes. 

A peat bed facility, as described by Valentin, consists of a concrete-lined rectangular pit, a raised perforated floor to support the peat bed, and an underfloor distribution area for the polluted air feed. The peat bed is typically a mixture containing about one-half sphagnum or trichophorum peat and about one-half woody heather or brush wood, which is added to minimize consolidation of the peat. The bottom layer is entirely heather to aid in air distribution, and the entire bed is about 1 m (39 in.) deep. A plastic membrane is used at the walls to prevent air bypassing. 

---