List of figures

Fig. 1: A fannyard biogas plant
Fig. 2: Feed material tables
Fig. 3: Simple biogas plants
Fig. 4: Fixed-dome plant
Fig. 5: Floating-drum plant
Fig. 6: Digester and gasholder
Fig. 7: Gas production from cattle manure
Fig. 8: Gas production from pig manure
Fig. 9: Graphic determination of gasholder volume (1)
Fig. 10: Graphic determination of gasholder volume (2)
Fig. 11: Digester/gasholder ratio
Fig. 12: Dependence of shape on retention time (floating-drum)
Fig. 13: Dependence of shape on retention time (fixed-dome)
Fig. 14: Biogas plants for a test programme
Fig. 15: Measuring gas production on the plant
Fig. 16: Shape and load-bearing capacity
Fig. 17: Same volume - different shape
Fig. 18: Pattern of stresses in a fixed-dome plant of mesonry construction .
Fig. 19: Cracks in the gas space of a fxed-dome plant
Fig. 20: The bottom slab
Fig. 21: Construction of a spherical shell from masonry
Fig. 22: Testing of mortar sand
Fig. 23: Mixing tank at inlet
Fig. 24: The inlet
Fig. 25: Path of the fermentation slurry in the digester
Fig. 26: Hemispherical plant with partition wall
Fig. 27: Stirring facilities in the digester
Fig. 28: Outlet (overflow) of a floating-drum plant
Fig. 29: The gas drum
Fig. 30: Forces on the gas drum
Fig. 31: Floating-drum guide frame
Fig. 32: Unsuitable guidance systems for floating-drums
Fig. 33: The water jacket
Fig. 34: Comparison of floating drums for waterjacket plants and for plants with internal gas outlet
Fig. 35: Correct height of compensating tank
Fig. 36: Shape of compensating tank
Fig. 37: Detail of a fixed-dome entry hatch
Fig. 38: Biogas: properties and utilization (tables)
Fig. 39: Pressure drop in gas pipes
Fig. 40: Condensate trap
Fig. 41: Diagram of a gas burner and a lamp
Fig. 42: Gas connection to diesel engine
Fig. 43: Drawing: floating-drum plant with funnel
Fig. 44: Drawing: floating-drum plant
Fig. 45: Drawing: floating-drum plant with an internal gas outlet and no water jacket
Fig. 46: Calculation of dimensions
Fig. 47: Drawing: floatingdrum plant with water jacket
Fig. 48: Drawing: fixed-dome plant without upper opening
Fig. 49: Drawing: fixed-dome plant with upper opening
Fig. 50: Drawing: floating-drum plant (vertical)
Fig. 51: Drawing: plant with extremely low VD/VG ratio
Fig. 52: Drawing: channel-type digester with folia
Fig. 53: Tables: Units of measurement
Fig. 54: Cubic metres and cubic feet; powers of ten
Fig. 55: Fundamental geometric formulae
Fig. 56: Fundamental static formulae
Fig. 57: Water pressure and earth pressure
Fig. 58: Change in volume of ideal gases under pressure and temperature
Fig. 59: Cross sections of common steels and pipes