Abstract: A system for recovering VOC contaminants from a surface or subsurface release. In one embodiment, the invention includes at least one horizontal trench having a perforated casing laid therein. One end of the casing is attached to a vacuum pump by means of a vertical riser. Clean stone is laid over the pipe to form an elongated collector and the surface of the trench is capped to minimize surface air and water infiltration. A suitable vacuum is applied and the VOC contaminates migrate first into the stone within the trench and then into the horizontal casing(s). The VOC contaminants move along the casings and up the vertical riser into a suitable container or directly discharged into the air. In a second embodiment, intermediate ones of the horizontal trenches are pressurized either by air or liquid fluids in either a heated or unheated state to improve the rate of migration of the VOC contaminates into the other alternating ISVE trenches exerting a negative pressure.

Abstract: The process of the present invention reacts a polyhydric alcohol and a second reactant selected from the group consisting of polycarboxylic acid, anhydride or an ester of a polycarboxylic acid in a first reactor to produce a flowable intermediate ester. During this reaction, volatile by-product is removed. The flowable intermediate ester is transferred to a holding vessel from which it is metered to a second reactor. Additional polyhydric alcohol may be added to the flowable intermediate ester which may be preheated by heat exchange with the finished polyester before introduction to the second reactor. A polyalkylene terephthalate feed is introduced to the second reactor in which it is reacted to form a finished polyester which is continuously removed from the second reactor. By altering the feeds to the second reactor, the physical characteristics of the finished polyester may be changed to meet various specifications.