Measuring Small-Scale Biogas Capacity and Production
Development Goal for energy (SDG 7)
"to ensure access to affordable, reliable, sustainable and modern energy for all."
-Survey of standardised plant types -Survey of biogas plant dimensions
(PLant Capacity) it then presents two options for colelcting this data:
1 MJ = 277.777778 Wh
1 MJ = _______Wh
1m^3 = 1000 liters
1m^3 = _____ liters
Biogas
A gas that is mostly methane and carbon dioxide
Khadi and Village Industries Commission (KVIC) digester
A popular design of a floating drum digester
75%, 25%
A review of the literature on ballon digesters suggests that the digester volume is around _____ of the total plant volume and the gas storage volume is around ____.
applicance use
A second method to estimate biogas production
Appropriate Rural Technology Institute (ARTI)
A variation of a floating drum digester is the small-scale above ground floating drum plant developed in India by the ______.
Digester
An air tight container in which bacteria break down organic waste through a process of anaerobic fermentation
liquid waste (slurry)
As more material is added to the digester, a ___ is also produced, which can be used as a fertilizer.
Bioga Institute of the Ministry of Agriculture in China
BIOMA stands for:
Anaerobic fermentation
Bacteria break down organic waste through a process of _______.
Latin American countries
Balloon digesters are often used in______.
megajoules(MJ)
Biogas data is usually reported in _____
-Carbon dioxide -nitrogen -small amounts of hydrogen
Biogas will also contain other gases such as:
Biogas
Can be used for cooking, heating and lighting, or it can be used to generate electricity
-National energy statistics -Project and policy monitoring -Tracking progress towards targets -Measuring environmental impacts -International energy statistics
Cite some examples on how biogas statistics may be used and the sorts of data that might be needed.
- 1m^3 of biogas = 0.65m^3 of methane - 1m^3 of methane = 34MJ of energy - 1m^3 of biogas = 22MJ of energy - 1m^3/day of biogas = 8060MJ / year
Conversion factors
-Vietnam (KT Model) -Tanzania (CAMARTEC Model) -Cambodia (modified Deenbandhu Design)
Countries that use Fixed dome plant (Hemisphere Design)
Plant Capacity
Estimate production from capacity data using capacity utilisation figure
Estimation methodology: -Plant capacity -Appliance use -Feedstock use -Fuel Subsitution -Direct Measurement
Five different methodologies for calculating or estimating biogas production and consumption:
China
Fixed dome plant was originally developed in _____.
Fixed Dome Plant (Hemisphere Design)
For this type of biogas plant, it is only necessary to measure the diameter of the base of the digester (D)
-by reducing emissions from fuel use -By reducing methane emissions from animal waste used in the digester -by using slurry from the digester as fertilizer (replacing commercial fertilizer produces with high energy inputs)
Households switching to biogas may reduce emissions in three ways:
weight of the dry matter divided by the total (wet) weight of the feedstock and is recorded as a percentage of the total(wet) weight.
How to get the total solid content
The volatile solid content is measured as the weight of the volatile solids in the matrial divided by the total weight of solids in the material and is recorded as a percentage of ther total solid content.
How to get the volatile solid content
International Renewable Energy Agency
IRENA stands for
plant capacity or plant size
In India, the exoected amount of gas produced each day may be called_____ or ____.
digester, gas storage tank
In a floating drum plant, the larger cylinder is the ____, which may be partly or totally underground and the smaller cylinder is the ____, which is placed on top and inside this.
20C-45C
In small-scale biogas plants, the bacteria that produce biogas work most effectively when the temperature of the slurry is ____
k = 0.4r
In volume calculation in deenbandhu design, k = _____
-Fixed dome plant (Hemisphere, Deenbandhu and Chinese Designs) -Floating drum plant -Ballon/bag digester
Key Digester Types
- An airtight environment with no oxygen - Moderate temperatures -No light -Small feedstock particles with broken-down fibers and minimal lignin(wood) content -For some feedstocks, a starter is also necessary
Key Requirements for Digester Operation
-Plant capacity -Total feedstock volume -Feedstock properties -Feedstock retention time -Temperature
Main Parameters are:
Digester
Main part of the biogas plant
65%
Methane content of a biogas was about_____.
moisture content
Most organic material contains a significant amount of water. This is known as its_______, as it is only water, does not contribute to biogas production.
National Domestic Biogas and Manure Program
NDBMP stands for:
-Mixing Pit -Steel gas drum -Central guide -gas outlet pipe - biogas -slurry outlet pit -inlet pipe -slurry -partition wall -outlet pipe
Part of a Floating Drum Plant
-Mixing pit -biogas -gas outlet pipe -displacement tank -inlet pipe -slurry -outlet pipe
Parts of a fixed dome plant
m^3/ day
Rated daily gas production was measured in ______.
0.65
The Digester Volume (Vd) can be calculated by multiplying Vp to ____
0.35
The Gas Storage Volume (Vg) can be calculated by multiplying Vp to ____
Voaltile solid content
The ___ is the proportion of the solid material that can be digested by the bacteria and turned into biogas in the digester.
Total Plant Volume
The ___ is the sum of two components: the digester volume and the gas storage volume
Waste volume
The ___ is the volume of organic material added to the digester
Chinese Design
The ____ design of a fixed dome plant consists of a hemisphere on top of a cylinder with a curve or flat bottom.
Rated daily gas production
The ____ is the volume of gas that a biogas plant is designed to produce each day if operated under optimal conditions.
Temperature
The ____ within the digester is an important variable that affects the speed of gas production (production per day) and the total amount of biogas that can be produced from any feedstock.
Deenbandhu Design
The _____ design combines a hemisphere with a curved base
the total solid content and the volatile solid content
The amount of material (feedstock) that can be digested will depend on two variables: the __ and the ___ of the material added to the digester.
Dead zone volume
The digester volume may also include a safety margin or ____
India
The floating drum plant was designed and developed in ______.
digester volume divided by the total feedstock volume
The retenstion time is measured in days and is simply calculated as the ________ divided by the ______.
cylindrical digester with a round top and flat or curved buttom
The typical Chinese fixed dome plant often consists of a _______ digester with a ______ top and _____ or ___ bottom.
Total feedstock volume
The___ is the average amount of aterial added to the biogas plant each day.
Hemisphere Design
This plant design consists oa a hemisphere with a flat bottom
Chinese Design
This type of digester is common in China and may also be found in other countries that have received assistance and training from BIOMA
Balloon digesters
This type of digester is usually amde from a large, strong plastic bag connected to a piece of drain pipe at either end.
-Biogas Plant designs and Capacities - Sampling and Interpretation of Results -Annual updating between surveys
Three important use of administrative data
m^3/day
Total feedstock volume is measured in_____.
Vp = (2/3)pi(D/2)^3
Total plant Volume formula for a hemisphere design
Vd = 0.75 Vp Vg = 0.25 Vp
Vd, Vg formula of a balloon digester
Vd = pi (D/2)^2 H Vg = (30/70) Vd Vp = Vd + Vg
Vd, Vg, Vp formula for a floating drum plant
Vp = D^3 / 2.2368
Vp formula for Chinese Design
Vp= (2/3)pi r^3 + (1/6)pi k (3r^2 + k^2)
Vp formula for a Deenbandhu Design
Vp = pi (D/2)^2 L
Vp formula of a balloon digester
Total plant volume
Vp is the symbol for
Balloon Digester
When fully expanded the shape of a _____ will be similar to that of a cylinder.
Water and feedstocks
___ and ____ are combined in the mixing pit which then flows into the underground digester through thte inlet pipe.
International Renewable Energy Agency (IRENA)
___ is intended to help countries collect and report their biogas data in an internationally comparable format
Total solid content
___ is the amount of dry matter present in the materal.
gas storage volume
____ is the amount of gas it can hold when full of slurry.
digester volume
____ is the maximum amount of slurry that the plant could hold.
Plan Capacity
____ is the maximum total volume of gas and slurry that can contain.
Floating Drum Plants
_____ are usually circular, so their volume can be calculated as the volume of two cylinders.
total plant volume
_____ if the calculations art referring to the volume of the plant
rated daily gas production
_____ in calculations when the calculations used an expected daily prioduction level
Safety margin or dead zone volume
_____ is used to prevent waste overflow on days when biogas production is higher than normal or biogas use is usually low.
Deenbandhu (developed in INDIA)
______ have a dome on top and a curve base.
CAMARTEC model (designed by GIZ for use in Tanzania)
______ is built as a series of brick rings in the shape of a dome on top of a flat base
40%
based on the specification of a number of different sizes of Deenbandhu digesters given in Kudaravelli(2013), the depth of the curve based on this design (k) is usually about ____ % of the radius (r) of the digester
direct measurement
biogas production is recorded over a perios of time by mechanical devices (flow meters)
appliance use
collect data on appliance us (hours per day and gas per hour) and use this estimate consumption.
feedstock use
collect data on digester size, technology and feedstock use and calculate the expected level of gas production
fuel substitution
collect data on fuel use in households with/without or befor/after connection to biogas and estimate consumption from the use of other fuels
Ratio 1:1
most biogas manuals recommend adding water to the waste in a ratio of ____
-Inlet pipe -biogas -gas outlet pipe -slurry outlet -slurry
parts of a Balloon/bag digester
Feedstock retention time
the ___ is the average amoun of time that feedstock will saty in the digester before they are pushed out throught the outlet pipe.
plant capacity
this method is the simpliest way to estimate annual biogas production
m^3
total plant volume is measure in_____.
Added water volume
volume of water being added to the feedstock