The Porcupine Processor -- Problem Solving Capabilities
Problem Solving Capabilities Bethlehem Porcupine ® Processor
One of the most common problems with indirect heat-transfer units is fouling of the heating surface. Breaker bars mounted on opposing side walls of the vessel promote more intense internal mixing. The differential velocity between the heated, rotating agitator and the process mass increase both heat transfer and the shear at the paddle surface. Fouling is frequently prevented by this shearing action.
Several fouling applcations can be solved by internal or exteral recycle. With recycle, a portion of the product is mixed with the feed stream to decrease the moisture content below that at which fouling tends to occur.
Industrial and municipal sludge, dewatered by filtration (centrifuge/press/vacuum), can be dried very effectively with the PORCUPINE® Processor. Dried municipal sludge can be converted to steam for heating the PORCUPINE® Processor. Resultant fuel savings make this technique the most cost effective means of municipal sludge disposal.
Most industrial sludges can be dewatered for economic land disposal. The uniformity of product material eliminates the need for further treatment of the waste. Mass and volume reduction created by the unique agitation of the PORCUPINE® agitator further enhance this means of industrial sludge disposal.
Dusting is created by high vapor velocities through -- or over -- solids of small particle size. High vaulted vapor space can drastically reduce the velocity of a vapor over the process bed and allow entrained particles to settle. Low speed of the agitator combined with the ability to operate without purge gas will minimize mechanical fluidization of the bed solids. This reduces the potential for entrainment. The PORCUPINE® provides one of the highest heating surface-to-volume ratios possible.
The unique hollow, cut flight agitator promotes highly efficient, localized mixing. This mixing action increases the intimate contact of the processed particles with the heat transfer surface of the agitator blades promoting close temperature control for heat sensitive products, high thermal efficiency and superior product quality.
The PORCUPINE® provides one of the highest heating surface-to-volume ratios possible. The very high area-to-volume ratio results in minimum residence ("dwell") time assuring a favorable time/temperature history. Vacuum operations or sparging with an inert gas may be employed to lower the partial pressure of a solvent.
HEAT TRANSFER MEDIUMS:
With two-zone temperature processing in a single shaft, it is possible to employ counter-current or concurrent flows in a parallel-series system for the heat-transfer medium and process mass. A complete spectrum of heat transfer mediums -- from 700°F hot oil to steam, hot or cold water or a special medium -- may be used.