Abstract: A method and apparatus are provided for enhancing the performance capability of an existing natural draft cooling tower(13). The cooling tower includes a structure (14) defining an open-topped internal passage (15) ofcircular cross section for the upward flow of air from one or more inlets (16) at the base of the structure. The method includes steps of providing within the passage (15), an impeller (27) adapted when mtated at a specified speed about an upright axis of rotation (28) centrally located in the passage to increase the overall flow rate of air in the passage beyond the overall flow rate obtainable in the same operatiny conditions by natural draft alone and provides support means for said impeller and drive means capable of rotating the impeller at the specified speed. The impeller (27) is supported by the supporn means above heat transfer means (19) (which may be a wetted packiny structure) of the cooling tower (13).

Abstract: A process for producing C1-C4 alkyl esters of fatty acids comprising the steps of: (a) reacting glycerine with a glyceride mixture containing levels of free fatty acids which inhibit trans-esterification with alkaline catalysts until the level of free fatty acids is reduced sufficiently to enable the use of an alkaline trans-esterification catalyst; (b) reacting the mixture resulting from step (a) with one or more alkaline trans-esterification catalysts and one or more C1-C4 alcohols until a mixture of one or more C1-C4 alkyl esters of fatty acids and crude glycerine forms; (c) recovering the one or more C1-C4 alkyl esters of fatty acids; and (d) recovering the crude glycerine, wherein at least a portion of the crude glycerine recovered in step (d) is used in step (a) of a subsequent process.