More extract from solids

New process including equipment to increase the efficiency of the ­treatment of very fine solids in counterflow liquids

Summary: A concept is presented according to which a uniform velocity of liquids is ­achieved in counterflow to solids over the cross-section of the vessel. Convections of ­higher liquid layers into lower ones can be excluded. The difficulty is the structure of the solid with many particle sizes in the range of approx. 20 to 0 mm as well as the input of a pulsation due to the gas flow. Amongst other things, this concept may be used for the ­extraction of wax from lignite or for the decontamination of soils in oil fields. The system impedes emissions, reduces the danger of explosion and can be operated under pressure.

1 Introduction

The continuous treatment of solids with liquids in counterflow in a vessel is a widespread field of process engineering. These are processes such as chemical reactions, the extraction of soluble substances from solids by means of a liquid solvent, sorption, dissolution and washing processes or others.


One of the most important prerequisites and the aim of such processes is the uniformness of the flow rate over the cross-section when passing the two phases in the vessel, i.e. the retention time of the liquid and of the solid must be very uniform when passing the vessel. These...

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