Plug flow fermenter for a biogas plant

A plug flow fermenter for a biogas plant, said plug flow fermenter comprising:

• a reactor vessel comprising a tubular body having a longitudinal axis that extends in a horizontal orientation, said tubular body defining a reactor interior configured to direct substrate along said longitudinal axis in a generally linear flow path;
• wherein said reactor vessel includes at least one inlet positioned at a first longitudinal end of said reactor vessel, and at least one outlet positioned at an opposite longitudinal end of said reactor vessel spaced apart from said at least one inlet, said at least one outlet permitting discharge of fermented substrate from said reactor interior along said longitudinal axis;
• wherein a plurality of separate agitator devices are arranged in said reactor interior, said plurality of separate agitator devices being spaced apart in linear fashion along said longitudinal axis, each agitator device comprising a shaft with at least one agitator blade mounted thereon, said shafts being oriented perpendicular to said longitudinal axis and configured to impart localized mixing of said substrate as said substrate flows along said longitudinal axis;
• and
• wherein at least one of said plurality of separate agitator devices is mounted within a vertically oriented installation opening formed in an upper portion of said reactor vessel, said installation opening being dimensioned such that said agitator shaft and said at least one agitator blade can be inserted through and removed through said installation opening without removal of adjacent reactor components during a fermenting operation.