KILOWATTS FROM CORNOBS

Article Tools

Image Gallery

Print

E-mail

Comments

RSS

In effect, this not only reduces temperature variations within the combustion chamber, but also expands that zone to provide an increase in gas production without enlarging the 16" hearth diameter. (The design has, after 100 hours of running time, shown no slag buildup, minimal start-up times, and consist ent temperature levels, while still being stonesimple. In all fairness, though, a constantspeed powerplant, such as the type used with this generator, places relatively few requisites upon a gasifier ... because of the fact that gas demand doesn't ever fluctuate with varying engine speeds.)

The hearth's size, configuration, and composition were based upon the nature of the fuel and the cost of the hearth. Although historical data indicated that a specific hearth diameter was necessary to supply a given size of engine, and that a restriction within the chamber was desirable to maintain sufficient temperatures, Haug successfully used a 16"-diameter straight steel pipe, and merely installed a movable grate inside it to serve as a shaker. Because there appeared to be no need to "funnel down" the flow of gases, there was no reason to cast the hearth into a special shape. Thus additional savings were realized.

By the same token, it was decided-with an eye toward the eventual commercialization of the technology—not to try to upscale the unit to suit larger powerplants. Instead, a modular approach—in which additional small gasifiers could be added on line as required-seemed more desirable from both a technical standpoint (the single hearth for a 1,000-KW plant would need to be a flow-choking sixfeet in diameter), and a practical one (parts availability and interchangeability would be a problem in gargantuan-scale gasifiers).

Finally, in an effort to determine what the minimum assembly costs might be, the Odin team experimented with a variety of metal and PVC cooling mechanisms, wet and dry filters, and simple moisture traps ... all of which would serve to prepare the gaseous fuel prior to delivery to their 35-KW diesel generator. The best results were realized by using steel cooling towers housed in water jackets ... installing flat-nipple, vacuum-operated diesel truck water traps in the gas pipe ... and mounting a dry cyclone filter—followed by a percolating oil-bath chamber—in the line directly before the Detroit diesel generator's air inlet.

Since the standby powerplant used in their research wasn't equipped with a dual-fuel system, the Odin folks had to make do by merely introducing fuel gas into the engine's airstream. Unfortunately, the design of their particular powerplant didn't lend itself a full range of pilot fuel adjustment, so they, could only operate on a maximum of 80 corn gas. (Norwegian studies indicate that 24 little as 8% diesel pilot fuel can be used when the injection is properly adjusted, and that only a 20% sacrifice in output, as compared to that when diesel fuel alone is used, will occur under these conditions.)

RSS | Comments | E-mail | Print