Apparatus for continuous hydrolysis

An apparatus for continuous hydrolysis of sludge comprising material of biological origin, the apparatus comprising:

• a reactor
• an inlet for feeding sludge into the reactor in a feeding zone thereof,
• an inlet for feeding steam into the apparatus in a steam feeding zone of the apparatus, thereby injecting steam into the sludge,
• an outlet for allowing processed sludge to exit the reactor,
• wherein at least a part of the reactor forms a first ascending zone in which the sludge during use flows in an upwards direction, and a first descending zone in which the sludge during use flows in a downwards direction,
• the apparatus further comprising:
• a first gas collecting zone defined in a transition between the first ascending zone and the first descending zone, the first gas collecting zone comprising a first gas outlet which is arranged such that a part of the gas collected in the first gas collecting zone can be removed from the apparatus, via the gas outlet, and a part of the gas collected in the first gas collecting zone remains in the first gas collecting zone when the first gas outlet is opened.

A method for operating an apparatus for continuous hydrolysis of sludge comprising material of biological origin, the method comprising the steps of:

• feeding sludge into a feeding zone of a reactor,
• feeding steam into a steam feeding zone of the apparatus, and injecting steam into the sludge,
• passing the sludge, in an upwards direction, through a first ascending zone,
• passing the sludge, in a downwards direction, through a first descending zone,
• collecting gas in a first gas collecting zone defined in the transition between the first ascending zone and the first descending zone, and
• removing at least a part of the gas collected in the first gas collecting zone, via a first gas outlet, while allowing a part of the gas collected in the first gas collecting zone to remain in the first gas collecting zone.