Download Mariska_Biogas_examples

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Anaerobic digestion wikipedia, lookup

Flixborough disaster wikipedia, lookup

Biogas wikipedia, lookup

Landfill gas utilization wikipedia, lookup

Piper Alpha wikipedia, lookup

Transcript
Biogas for households
Mariska Ronteltap, PhD
Lecturer Sanitary Engineering and Resource Oriented Sanitation
Department of Urban Water Supply and Sanitation, UNESCO-IHE
Biogas systems
• Not so suitable for sole households without
animals
• Very suitable for block of households / in
combination with other wastes
• Relatively cheap; requires experience but no
high tech skills / equipment
Size of the system
• The size of the plant depends on the substrate
available
• Volume chosen for number of cattle/ pigs
• Larger plants = longer HRT = more gas
• But: amount of daily fed substrate more
important for gas production than digester
volume
Standard sizes
• In some countries where biogas systems are important,
standard sizes are chosen
• This simplifies construction, operation and maintenance;
makes material cheaper
Example:
• 16 m³ for gas for cooking and lighting for a normal family
• 12 m³-plant for places of little gas demand
• 30 and 50 m³-plants: fuel for big institutional kitchens
and special appliances (refrigerators, power engines)
Construction
The plant consists of
• non-load bearing bottom (A),
• lower slurry-tight digester (B),
• the upper gas-tight gas storage
part (C),
• neck (D) and gas-tight lid (E).
• Gas storage part and digester
are separated by the weak ring
(10) in order to allow free
reaction of the strong-ring (3)
and to prevent cracks which
have developed in the lower
part of the digester to "grow"
into the gas storage space.
Construction
• Plant rests on foundation ring (1),
bearing mainly the vertical loads of'
the construction and the soil cover
(7).
• The surrounding soil supports the
construction to resist gas pressure
(5) and slurry pressure (6).
• Concrete at the outside of the
lower layer of bricks (2) helps to
reduce tangential forces at the foot
point (9).
• The ring forces of the upper part
are absorbed by the strong-ring
(3).
Inlet and outlet
• Inlet and outlet pipe must be
placed in connection with bricklaying (Breaking holes spoils the
whole structure)
• The pipe rests below on a brick
projecting 2 cm to the inside.
• Above, it is kept in position at the
rim of the excavation.
• Inlet: 10 cm diameter; in line with
top of weak ring
• Outlet: 15 cm; starts at 4th brick
layer