Abstract: The object of the present invention is a method for the separation and recovery of furfural and organic volatile acids from a vapor mixture obtained in the process of preparation of furfural. According to the method, from a vapor mixture containing water vapor, furfural and organic acids and escaping from a reaction vessel operating on the counter flow principle, wherein the reaction to form furfural takes place, organic acids are separated and recovered before the vapor mixture is condensed and conducted to the furfural concentration process. The separation is performed by absorbing the organic acids from the vapor mixture into the concentrated furfural solution in an absorption tower operating on the counter flow principle and by subsequently separating the furfural and organic acids from each other by means of vacuum distillation.

Abstract: An apparatus for portioning of solid vegetable raw material from a storage space into a reactor under pressure. A sluice space closed by an upper and a lower slide type gate is provided between the storage space and the reactor for supplying the material into the reactor through the sluice space. Each gate comprises a chamber and a slide slideably provided therein for alternately opening and closing the connection between the storage space and the sluice space and the connection between the reactor and the sluice space respectively. The chamber of the slide chamber of the lower gate is connected at that end, which is positioned remote from the sluice space, by a pressure levelling channel to the storage space and the chamber of the slide chamber of the lower gate is at the corresponding end connected by a further pressure levelling channel to the sluice space.