hptc_broschure_26.02.08

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HPTC Biogas Plant High Performance Temperature Controlled Biogas Plant

BME GmbH Deimel 1 84329 Wurmannsquick Germany

Ph +49(0)9954 – 90 240 F +49(0)9954 90 241 Email [email protected]

Rottaler Modell HPTC Biogas Plant

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Table of Contents

Background of the Rottaler Modell (RM) HPTC Biogas Plant ....3

RM HPTC Biogas Plant in Brief..................................................4

Advantages of an HPTC Biogas Plant .......................................5

Feedstock and its Biogas Potential ............................................6

Feedstock Production with Energy Crops ..................................7

Why Temperature Controlled? ...................................................8

Basic Equipment of a HPTC Biogas Plant .................................9

Basic Layout Plan – HPTC Biogas Plant..................................10

Economics................................................................................11

Checklist for the Engineering of an HPTC Biogas Plant ..........12

Contact .....................................................................................13

BME GmbH Deimel 1 84329 Wurmannsquick Germany

Ph +49(0)9954 – 90 240 F +49(0)9954 90 241 Email [email protected]


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Background of the Rottaler Modell (RM) HPTC Biogas Plant HPTC – High Performance, Temperature Controlled Availability of energy is critical to economic and technical development. In developing countries, the majority of the people have no access to energy and have therefore no opportunity for developing and improving their lives. To change this situation BME GmbH developed the high performance temperature controlled biogas plant (HPTC) for the production of gas for cooking and in combination with a genset for the production of electricity from biogas. The HPTC biogas plant is a high performance, small and modular biogas unit. Due to the special engineering and design a very high biogas production is possible. Different volumes and capacities are possible. The design is adapted to the demand and circumstances of the living conditions in rural areas especially in developing countries. Production of thermal and electrical energy from biomass or organic waste and production of fertilizer. Different locally available biomass as organic waste from households, markets, kitchen waste, villages or restaurants or from residues from food processing, but also biomass from the fields can be used as feedstock for the HPTC biogas plant. Due to the special design high fibrous material can be digested also. Local resources in rural areas can be used for the production of energy crops such as grass, sorghum or other available local plants. New jobs can be created for the feedstock production and also for the operation of the HPTC biogas plant. Availability of cooking gas and electricity causes development and enriches the whole region. The value remains in the community.


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RM HPTC Biogas Plant in Brief HPTC – High Performance, Temperature Controlled Applications at

Boarding schools, school kitchens Villages Restaurants

Products

Cooking gas for households or big kitchens for schools or orphan homesor similar applications Electricity: The biogas can be used in a genset to replace up to 80% of the diesel to produce electricity. Bio-Fertilizer: The digested feedstock is after the digestion a highly valuable fertilizer.

Feedstock Gras, Sorghum, Market waste Agricultural waste, Food processing waste Fish waste Kitchen waste Oil press cake

System Two-stage digestion system with 1) Hydrolysis and acidification 2) Methanisation

Performance

10-15 times higher than the manure biogas plants due to 1) temperature control 2) hydrolysis and acidification 3) high calorific feedstock

Digester volume

25 m3

Biogas production Ca. 60 m³ per day (20 m³ net digester volume x 3 m³ biogas per

m³ digestion volume per day) Methane content: 55-60% 60 m³ biogas x 60% =36 m³ methane. Equivalent to 26 kg LPG or 90 kg wood (100% dry) or 36 litre diesel

Temperature Controlled temperature, 37°C, insulation and solar heating system

Digester/Biogas bag material

Plastic bags with a 3 layer material

Safety devices “Flame arrester” for blocking fire backstroke “Overpressure Valve” for regulating the gas pressure in the gas system “Solenoid valve” for blocking the gas flow to the genset while not producing electricity

Installation time 7 days


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Advantages of an HPTC Biogas Plant Various kinds of biomass are suitable The small biogas plants in developing countries are known for the digestion of cattle or pig manure. The HPTC biogas plant can use the same feedstock and is not limited to these kinds only. All kind of organic waste – market waste, agro-processing waste, etc – is a good feedstock for the biogas production. Further more the farmers can produce also energy crops like gras, sorghum or maize for biogas production. Below you can see different kinds of feedstock available for digestion in HPTC biogas plants. Grass Maize / Sunflower Sorghum Straw Dry grass Stems (banana i.e.) Stems (cutted) Leaves Vegetable Organic waste Everywhere! feedstock is available. In the suburbs of cities or remote villages. The HPTC offers the opportunity to produce biogas everywhere. Independently from livestock! Local Waste Management Waste is a nuisance everywhere. There is no use and everyone dump it – the results are bad smell, diseases and water pollution. With the HPTC the organic fraction of the waste can be used for producing energy and fertilizer. Coincidentally the bad smell can be avoided. Productive Use Development – especially in rural areas – is blocked almost by a lack of energy. The typical manure biogas plant doesn’t produce enough biogas for the operation of a genset. The HPTC provides enough biogas to run a genset for 10 hours a day. The electricity fuels milling machines and other productive applications. Savings for the Rural Community Diesel is the main fuel for electricity production in remote regions. Diesel is expensive and electricity from diesel drains the money from the villages. The HPTC uses local produced feedstock. Electricity from HPTC gives income for the local farmers and provides job opportunities for the local people.


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Feedstock and its Biogas Potential The biogas potential of the feedstock differs from each other. Some organic substances produce less biogas, some have a high biogas production rate. The daily feeding rate of the HPTC biogas plant has to be adjusted to the available feedstock and depends on how much biogas or electricity should be produced for the daily use. Daily Feeding Rate The table shows the feeding rate of the feedstock for the daily maximum biogas production of 60 m³ biogas per day. The biogas has a methane content of 60% and this results in a daily methane production of 36 m³.

Feedstock Feeding rateDry

Matter Volatile Solids Biogas

Methane yield per day

kg/day % % m³ CH4/kg VS m³ CH4 cattle manure (liquid) 1030 8 80 0,55 36 cattle manure (solid) 330 25 80 0,55 36 Grass (fresh) 470 21,1 91 0,4 36 Market waste 400 25 90 0,4 36 Vegetable waste/market waste 400 25 90 0,4 36 Fish processing waste 270 30 90 0,5 36 Food waste (from canteen kitchen) 185 40 98 0,5 36 Park and garden waste (fresh) 175 42 97 0,5 36 Organic waste (domestic) 90 75 90 0,6 36 Oil seed residue (pressed) 65 92 97 0,62 36

Source: Figures KTBL, own calculation One m³ of methane has an energy content of 10 kWh; this is the same as 1 litre diesel or 1 m³ natural gas. The maximum dailys biogas production can replace

• 26 kg LPG (liquified petroleum gas) or • 36 litres diesel or • 90 kg of wood (100 % dry)

To produce a methane yield of 36 m³ per day feeding rates between 1030 kg and 65 kg per day are necessary depending on the kind of feedstock. vegetable waste fish waste market waste grass


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Feedstock Production with Energy Crops Beside waste energy crops can be a source of feedstock for biogas production. The table shows an example how to calculate the farmland demand to run a HPTC. Qty. unit Methane production per day 36 m³ Methane production per ton of grass 77 m³ Grass as feedstock per day 0,470 tons Grass as feedstock per year 172 tons Grass yield per ha and year 40-60 tons Area demand for grass production 4,3 ha

Fig.: Gas bag installation in Mombasa With 1 ton of fresh grass 77 m³ methane can be produced. To reach the daily maximum biogas yield around 420 kg of fresh gras as feedstock has to be harvested and fed to the biogas plant. For one year the HPTC needs 125 tons of fresh grass. The yield of one hectare grassland is 40 tons per year. To run an HPTC around a year 4,3 hectares of land are necessary. With 4,3 hectares of land

• a village can produce enough biogas for cooking of 50 families • a boarding school can replace the fire wood for the kitchen • a genset with the elcectrical capacity of 12 kW can run 10 hours a day and

gives electricity for 120 families (100 watt/family) or drives machines for productive use like grain mills or oil mills.

During the dry season the fresh grass can be replaced by grass silage, which is produced during the rainy season.


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Why Temperature Controlled? A constant temperature is crucial for many biological processes. Biogas bacteria come from cattle stomaches, which are mammals and require a constant body temperature of 37 oC. The biogas plants in developing countries are designed to digest cattle or pig manure without any technical controll or heating system. Therefore the biogas yield per m³ digester volume and day is very low. And these systems can’t digest waste, energy crops and other high calorific feedstocks. Temperature controll for the HPTC Temperature is one important key for a high performance digestion system and therefore a high biogas production. Also temperature is important for a stable biology in the digester. To maintain a constant temperature on the mammal level without mayor fluctuations to digester bag is insulated on the top. A solarthermal heating system with heating coils in the digester heats the liquid.

The picture shows the performance curve of biogas plants depending on the temperature level. The optimum temperature is at 37 oC and 55 oC. Above and below the performance is reduced. Solar heating systems for HPTC biogas plants in Kenya and India

Temperature in the Digesters

Mesophilic digestion Temperature: ~ 35 oC

Thermophilic digestion Temperature: ~ 55 oC

Activity at T oC in % Activity at 35 oC

20 30 40 50 60 oC

150 100 50

thermophilic

mesophilic


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Basic Equipment of a HPTC Biogas Plant The Standard HPTC Biogas Plant is composed of:

• 25 m³ digester bag (with insulation) • 20 m³ biogas storage bag • two 4 m³ hydrolysis units • overflow unit to store the recirculate / fertilizer • solar heating system to heat the digester

(heating pipes, circulation pump, solar control system)

• desulphurisation pump • bio filtering system for filtering the hydrolysis

gas generating in the hydrolysis unit • gas pipes Digester bag • pipes (gas pipe, hydrolysis pipe to the digester,

overflow of the digester) • over pressure valve and condensation trap • others (roofage), civil engineering, ground

work • operating instructions and manual

Services:

• installation of the HTPC biogas plant • workshop and training of the local staff Gas storage bag • start up

Genset Overflow units / Digester bag unit


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Basic Layout Plan – HPTC Biogas Plant


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Economics The following calculation shows the comparison to LPG. Revenue or Energy Savings in Comparison to LPG quantity unit country Biogas production per day 60 m³ Methane content 60% Methane production per day 36 m³ Weight of methane 0,72 kg/m³ Methane production per day 25,9 kg Volume of 1 LPG cylinder 13 kg Kenya Price of 1 LPG cylinder 23 US$ Kenya Methane production in LPG cylinder equivalent 2,0 cylinders LPG Value of the biogas production in comparison to LPG per day 45,9 US$ Value of the biogas production in comparison to LPG per year 16.738 US$ 13.391 € Investment in a 25 m³ HPTC Biogas Plant Cost in € Material and Installation 30.000 € Operating Costs Feedstock 860 € Energy crop production per ha in € 200 Hectare per year 4,3 Operator 600 € Salary per month in € 50 1.460 Profit per year 11.931 Payback period 2,5 years


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Checklist for the Engineering of an HPTC Biogas Plant

Questions Comment Amount Which feedstock is available?

Is the feedstock available throughout the year?

If not, is there any possibility for conservation and production of silage?

Biogas usage: thermal or electrical use?

Local electricity price? (money per kWh) Local LPG price?

Electricity: Describe the demand curve during the day. Highest demand?

Operator: Is a person as operator available?

Temperature curve throughout the year

Soil: Which soil is at the planned site? Sandy, clayey, rocky, firm, profound

How is the groundwater level?

Is the site free from floods?

Are craftsmen locally available for the construction?

Other relevant comments?


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Contact For questions to the HPTC Biogas Plant please contact: Dipl.Ing.agr. Walter Danner

[email protected] Dipl.Ing.agr. Ulrich Gams

[email protected] BME GmbH Deimel 1 84329 Wurmannsquick Germany ℡ +49 (0) 9955 – 90 240

+49 (0) 9954 – 90 241 [email protected]

Created by BME GmbH – 2/2008

hptc_broschure_26.02.08

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