Table of Contents
Biogas - Application and Product Development ............................................................................. 4
Planning a biogas plant ................................................................................................................................... 4
Design............................................................................................................................................................. 4
Types of plants................................................................................................................................................ 5
Parts of a biogas plant..................................................................................................................................... 5
Construction details ........................................................................................................................................ 6
Starting the plant............................................................................................................................................. 6
Managing input- and output-material ............................................................................................................. 6
Biogas - Digester types ...................................................................................................................... 8
Fixed-dome plants .......................................................................................................................................... 8
Floating-drum plants..................................................................................................................................... 11
Biogas Plant Types and Design....................................................................................................... 15
Digester types in industrialized countries ..................................................................................................... 15
Selection of appropriate design..................................................................................................................... 16
Ballon plants ................................................................................................................................................. 17
Horizontal plants........................................................................................................................................... 17
Earth-pit plants.............................................................................................................................................. 17
Ferrocement plants........................................................................................................................................ 18
Parts of Biogas Plants...................................................................................................................... 19
Influent collecting tank ................................................................................................................................. 19
Inlet and outlet .............................................................................................................................................. 19
Digester......................................................................................................................................................... 20
Gasholders .................................................................................................................................................... 22
Gas pipe, valves and accessories .................................................................................................................. 24
Stirring facilities ........................................................................................................................................... 25
Optional Parts of Biogas Plants...................................................................................................... 26
Heating systems ............................................................................................................................................ 26
Pumps ........................................................................................................................................................... 26
Weak ring ..................................................................................................................................................... 27
Balancing Biogas Production and Energy Demand...................................................................... 29
Determining the biogas production............................................................................................................... 29
Determining the energy demand................................................................................................................... 29
Biogas Planning Guide .................................................................................................................... 32
Detailed planning guide for biogas plants..................................................................................................... 32
Step-by-Step Planning Checklist for Biogas Plants ...................................................................... 38
Sizing a biogas plant ........................................................................................................................ 39
Sizing the digester......................................................................................................................................... 39
Calculating the daily gas production G ........................................................................................................ 39
Establishing the plant parameters ................................................................................................................. 39
Sizing the gasholder...................................................................................................................................... 40
Siting of the Biogas Unit.................................................................................................................. 41
Stable ............................................................................................................................................................ 41
Biogas plant .................................................................................................................................................. 42
Substrate types and management................................................................................................... 43
Cattle dung and manure ................................................................................................................................ 43
Pig dung and manure .................................................................................................................................... 43
Goat dung ..................................................................................................................................................... 43
Chicken droppings ........................................................................................................................................ 44
Human excrements ....................................................................................................................................... 44
The problem of scum .................................................................................................................................... 44
Construction Details of Biogas Plants............................................................................................ 46
Checklist for building a biogas plant ............................................................................................. 46
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