US 5,200,085 A · Process and apparatus for extraction of solid matter containing fat and/or protein from sludge

Abstract

According to the process the sludge is homogenized and heated to 30.degree.-60.degree. C. temperature. The heated sludge is circulated under 2-4 bar overpressure, and its temperature is raised to about 130.degree.-150.degree. C. in 1-2 sec by conducting steam of 130.degree.-151.degree. C. and 2-4 bar pressure directly into the sludge, thus granulation is brought about in the sludge. The sludge of increased temperature --while its temperature and pressure maintained--is further circulated for about 60-300 sec. Then, the sludge is adiabatically expanded in 1-2 sec by reducing the pressure to about 0.01-0.02 bar. The expanded sludge is separated to water, fat containing water and solid impurity and wet solid phase containing protein. It is characteristic to the apparatus that it is provided with device for heating the sludge, and pipe (18) for passing on the heated sludge connected with the heating unit (5) where an expansion valve is built in. Pipe (22) joining the separating tank (7) is connected with the expansion valve (6). The apparatus is provided with separator for separation of the sludge leaving the tank (7) to water, fat and solid phase.

Claims14

Dependent claims

A process for the extraction of one or both of fat and protein containing material from waste water sludge, the process comprising the steps of:

circulating the waste water sludge in a circulating tank;
heating the waste water sludge to a temperature of 30.degree.-60.degree. C.;
pressurizing the waste water sludge to a pressure of 2-4 bar;
supplying the waste water sludge to a heating unit;
heating the waste water sludge to an increased temperature of approximately 130.degree.-150.degree. C. in 1-2 seconds in the heating unit to bring about granulation in the waste water sludge;
holding the waste water sludge in a heat holding pipe connected to the heating unit for approximately 60-300 seconds while the pressure of 2-4 bar and the increased temperature of 130.degree.-150.degree. C. are maintained;
expanding the waste water sludge adiabatically in 1-2 seconds by reducing the pressure to approximately 0.01-0.02 bar using an adiabatic expansion valve connected to the heat holding pipe;
supplying the waste water sludge to a separating tank;
and
separating the waste water sludge into water, water containing fat and solid impurity and a solid phase containing protein in a three-phase screw centrifuge connected to the separating tank.

7 more elements

An apparatus for the extraction of one or both of fat and protein containing material from waste water sludge, the apparatus comprising:

a sludge circulator for receiving and circulating the waste water sludge;
a first heating unit coupled to the sludge circulator for heating the waste water sludge during circulation;
a first pipe for supplying the waste water sludge from the sludge circulator to a steam injection heating unit for rapidly heating the waste water sludge to an increased temperature of approximately 130.degree.-150.degree. C. in 1-2 seconds;
a second pipe for holding the waste water sludge from the steam injection heating unit at a pressure of 2-4 bar and said temperature, and supplying said sludge to an expansion valve means including a compressed air pipe for adiabatically expanding the waste water sludge by reducing said pressure to about 0.01-0.02 bar in 1-2 seconds;
and
a third pipe for supplying the waste water sludge from the expansion valve to a separating means for separating the waste water sludge into water, water containing fat and solid impurity and solid phase containing protein.

3 more elements

Dependencies are inferred from the claim text.

Process and apparatus for extraction of solid matter containing fat and/or protein from sludge

Life of this patent

Process and apparatus for extraction of solid matter containing fat and/or protein from sludge

Life of this patent

Abstract

Claims14