Abstract: Method of pretreating citrus waste to break cell structure, pasteurize or sterilize citrus waste solids and remove inhibitory peel oil components (e.g., limonene) involving optionally reducing the particle size of the citrus waste prior to preheating, preheating the citrus waste through indirect heating in a preheater reactor to form preheated citrus waste and conveying the preheated citrus waste to a main reactor, heating the citrus waste through a combination of (simultaneous) indirect heating and direct heating to produce treated citrus waste solids that are pasteurized and a vapor containing water and peel oil components, separating the pasteurized citrus waste solids and the vapor containing water and peel oil components, and collecting the separated vapor containing water and peel oil components by condensation. The method optionally includes cooling the pasteurized citrus waste solids followed by saccharifying with enzymes and fermentation to produce ethanol or other products.

Abstract: A method and apparatus for vacuum cooling heated viscous and/or high solids mixtures employs at least one cooling tank (1) having inwardly sloping side walls (15) from a top (14) to an opening that is attached to a outlet pump or valve (7) located at the tank bottom, a rotational spreader (8) near the top and at least one vacuum pump (5, 6) to maintain the predetermined vacuum in the tank, and input and output pumps (20, 21). The rotational spreader (8) breaks up the heated viscous and/or high solids mixture (9) and distributes it onto the side walls of the tank to form a film (10) which is cooled as it travels to and slides down the sides to the bottom where the viscous and/or high solids mixture is outputted from the tank by a pump or valve (7, 21, 26). Multiple stages of the apparatus may be employed preferably with progressively greater vacuum pressure in each stage to accomplish even further cooling of the viscous and/or high solids mixtures.

Abstract: Method for producing ethanol from solid citrus waste by reducing the concentration of limonene in citrus waste to allow fermentation. In one embodiment ground solid citrus waste is partially hydrolyzed and pasteurized by heating using a jet cooker and then injected into a flash tank to remove limonene. The heated citrus waste is then cooled, hydrolyzed with enzymes and fermented to ethanol. The remaining solids and liquids may be processed further to yield other byproducts. More particularly, the solids may be dried and pressed for use in cattle feed and the liquids may be further fermented or processed to yield additional ethanol, acetate, galacturonic acid monomers and polymers, five carbon sugars and other products.

Abstract: Processes for producing ethanol from citrus waste by reducing the concentration of limonene in citrus waste to allow fermentation are disclosed. In one embodiment a slurry of ground citrus waste 1 is partially hydrolyzed by heating using a jet cooker 2 and then injected into a flash tank 4 to remove limonene 5. The heated citrus waste is then cooled, hydrolyzed with enzymes and fermented to ethanol. An alternative method of limonene removal uses enzymatic hydrolysis followed by centrifugation 27 to separate sugar-containing liquid from residual citrus waste solids containing limonene. Sugars are fermented and ethanol is distilled from the fermented mixture/beer. The remaining solids and liquids may be processed further to yield other byproducts. More particularly, the solids may be dried and pressed for use in cattle feed and the liquids may be further fermented or processed to yield additional ethanol, acetate, galacturonic acid monomers and polymers, five carbon sugars and other products.