biogas technology - ahk...

BIOGAS TECHNOLOGY

Reasons why the industry is

being undermined in

Nigeria

Avenam Links International Limited

4C, F&F Plaza, 44 Awoshoga Street,

Oniwaya Estate, Cement

Mobile: 234 8174382159, 7030070291

Email: [email protected]

Website: www.avenamlinks.com

Nina Chioma Ani

NOVEMBER 6TH 2014

Seminar on "Biogas”

mailto:[email protected]

http://www.avenamlinks.com/

INTRODUCTION Biogas technology is an alternative energy source which utilizes various

organic wastes in order to produce Biogas (cooking, heating and lighting), mineralized water and organic fertilizers.

Some countries hampered by natural abundance or inadequate distribution of energy supplies have often adapted biogas generating equipment to meet rural energy needs. Family size biogas generating units

have been used in diverse climates and cultures. In the 1970s when renewable energy became recognized as a separate subject, a conference on Biogas was held at Imperial College, University of London. The participants agreed on the big potential for biogas technology in many parts of the world, particularly the developing world. Nepal’s programme started very much in the same way as the India one, with a government

initiative. Progress was steady with the aid of Agricultural Development Bank of Nepal and there was rapid expansion in the late 1980s.

Biogas: An untapped source for power

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CONT. Animal droppings from cow, pig, poultry and crop residues have been used

in different countries. The degree of success of biogas technology varied for the different countries that employed biogas technology for rural energy supply.

Pilot biogas plant projects have been executed in some parts of Nigeria by ECN, UNDP, JICA, and some Tertiary Institution. There was a 10 m3 biogas

plant at Achara, Nsukka LGA, Enugu State which was executed by NCERD\UNN, for women cooperative garri processing. The plant fed on droppings of domestic animals, cassava peels and waste from the milling of cowpea, and bambara nut from the nearby food processing plant. There are so many other biogas plants in other parts of the country that are currently not working due to an increase in the number of poor quality

constructions and it is damaging peoples faith in the technology.


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CONT. The Ifelodun farmer’s cooperative at Ojokoro, Agege, had a piggry farm of

about 3000 heads and within the farm they operate an abattoir which processes the swine to pork for sale to members. ECN – SERC/UDU in 1998 built 20 m3 fixed dome bio-digester which was fed on pig waste and produces gas for cooking and natural manure which members use in their farm. At NAPRI, Zaria, a 20 m3 biogas plant was constructed in 1996 by SERC and in 1998; the centre constructed 30m3 biogas digester for Zaria

prison, which fed from human wastes. UNDP sponsored construction of 10 – 20m3 digesters in Kano, Yobe, Kebbi States, etc. Unfortunately most of the biogas plants in Nigeria are no longer functional due to lack of maintenance.


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WHAT IS BIOGAS

A mixture of methane and carbon dioxide

CH4

CO2 • Methane or ‘swamp gas’, produced naturally in swampy ponds


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WHAT IS BIOGAS TECHNOLOGY

Biogas technology is the use of biological process, in the absence of oxygen, for the breakdown of organic matter into biogas and a high quality fertilizer. Biogas is a combustible mixture of methane and carbon dioxide. The process also eliminates organisms that cause disease in humans and animals. Biogas technology is a "carbon neutral process," meaning it neither adds nor removes carbon dioxide from the atmosphere. Potentially, this technology is a significant and profitable way of mitigating global climate change.


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BENEFITS OF BIOGAS TECHNOLOGY

ANAEROBIC DIGESTER

Economic Benefit

Health Benefit

Energy Benefit

Environmental Benefit

Waste Treatment

Benefit


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BIOGAS APPLICATION

• Biogas is a fuel used as an

energy source for light, cooking, heat or movement


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HOW IS BIOGAS PRODUCED & TYPES OF

ORGANIC WASTE THAT CAN BE USED

Biogas is produced by the breakdown of

organic waste by bacteria without oxygen

(anaerobic digestion or fermentation).

Leftover food from houses,

shops, restaurants and

factories

Cow, sheep

and chicken

manure

Sewage

Leftover meat

and blood from

abattoirs

Leftover straw

and crops from

farming


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OTHER SUBSTRATES

SUBSTRATES FOR ANAEROBIC DIGESTION

AGRICULTURAL WASTES

INDUSTRIAL WASTE & WASTEWATER

MUNICIPAL BIOWASTE

ENERGY CROPS


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FACTORS AFFECTING BIOGAS PRODUCTION

Various factors such as biogas potential of

feedstock, design of digester, innoculum,

nature of substrate, pH, temperature,

loading rate, hydraulic retention time (HRT),

C : N ratio, volatile fatty acids (VFA), etc.

influence the biogas production.


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TYPES OF BIOGAS TECHNOLOGY

1) The Fixed dome: This consists of an airtight container

constructed of brick, stone or concrete, the top and

bottom being hemispherical. Sealing is achieved by

building up several layers of mortar on the digesters

inner surface if brick is used for construction. It is

relatively cheaper to construct the fixed dome

digester than the floating gasholder type.


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CONT.


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CONT. 2. The Floating gasholder: The design of this digester

was first developed by Indian’s Khadi and Village Industries Commission (IKVIC) and consists of a cylindrical container, the height to diameter ratio being in the order of 2.5 – 4.1:1, constructed of brick or concrete reinforced with chicken wire. The cover is usually constructed of mild steel. Cost, corrosion and maintenance of the cover have been the main problem of this design. However, the mild steel cover is gradually been replaced by plastic gasholder.


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CONT.

FLOATING TYPE BIOGAS PLANT


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CONT. 3. The Bag Digester This type of digester comprises of a long

cylinder, either polyvinyl chloride (PVC) or a material known as red mud, plastic – developed in 1974 from the residues of bauxites smelted in aluminum production plants. Incorporated in the Bag are inlet and outlet pipes for the feedstock and slurry and a gas outlet pipe. Gas produced is stored in the bag under a flexible membrane. The sizes varies from 2m3 to 50m3.

Some of the characteristics redmud-soft biogas bag is that the material pull good elasticity, anti-aging, good folding properties. To increase its performance, can be coated on the surface of Teflon coating to improve its anti-aging and self-cleaning ability, some of them have a life span of 15 years.


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CONT. Soft Bag Digester


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CONT. Soft Bag Digester


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PROBLEMS AND CHALLENGES OF BIOGAS TECHNOLOGY

PLANNING AND CONSTRUCTION

Site planning is an important factor. This comprises design issues concerning the construction, the gas distribution system, the feedstock storage, and as well as the utilization of by-products and the appropriate location.

The size of the biogas plant has to be suitable for the context. If the plant is over dimensioned, the

economical efficiency of the biogas plant decreases and the microbiological activity will be low


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CONT. Lack of Financial capabilities

Lack of financial capabilities to invest in biogas plants remain one of the biggest challenges.

A small household based biogas plant with a volume 6-8 m3 costs around N85,000 – N120,000.00. These figures are from China where the Chinese government also have subsidies making the investment even lower. Half of the investment is subsidised and the yields from the power plant will give an estimated yearly revenue of around N24,000.00 when taking into account savings from buying firewood and electricity, produced fertilizer etc. This makes the payback time less than two years in this example. This is affordable for most rural

households, even in poor areas.


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CONT. Lack of Public support

Public support is very important in the promotion of biogas. If the people don't have confidence in investing in biogas they will continue to use diesel fuel and other none renewable energy that are already available. Spreading information about biogas and it's positive effects is important. One approach is for the government to implement pilot biogas projects in rural agricultural areas to showcase the benefits of biogas technology. This is exactly what Avenam Links International is doing by constructing a 1,500 m3 biogas plant in phases.


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CONT.

LACK OF EFFECTIVE AND CLEAR POLICIES

The lack of effective and clear policies are a major hurdle to overcome in the dissemination of biogas technology. Governments need to actively set policies that promote biogas usage and encourage collaboration with governmental organisations (GO) and non-governmental organisations (NGO). If the Nigeria Government have little capacity of financing biogas projects collaboration with GO:s and NGO:s can increase chances of foreign funding and technological import. If our government doesn't have any policies to aid biogas promotion, eg. subsidies and loans, it will be much harder for local entrepreneurs and organisations to build biogas digesters for poor rural households.


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CONT. TECHNICAL PROBLEMS

There are several technical problems that can arise.

If there are heavy rains, biogas digesters that are below ground can get flooded and as a result have to be drained which adds to the maintenance time and costs. This can easily be avoided with better site design planning when the biogas plant is built.

Other technical issues are mostly related to bad maintenance. A common problem is that pipes get blocked due to lack of service. Leakage is also a problem that is not unusual with fixed dome biogas plants. Methane (biogas) is a poisonous gas as well as an aggressive GHG.


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Why Biogas technology is undermined

in Nigeria

We all know that the Biogas technology is gaining more recognition in Nigeria compared to years back but there is still this growing concern among many stakeholders if the plant will stand the test of time. From my little research carried out, I have come to realize that most potential clients who once had a demo plant have lost faith in the technology due to their past experience with their previous plant which failed as a result of poor quality construction executed by untrained mason constructing low quality plants.

Some of the State Government who have invested in the construction of the pilot plants that have failed have lost faith in the technology and not willing to promote it financially.

Banks do not have confidence in the industry because there are few or no plant in operation where they can work in an see the viability of the technology.

There are few stakeholders/Entrepreneur in biogas who can help to promote quality as well as quantity that can help boost confidence, which can help in expanding this technology into a widespread and sustainable industry in Nigeria.


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REASONS FOR FAILED BIOGAS PLANT

Examination of failed projects in Nigeria shows that the under listed were the major reasons for the malfunctioning of the biogas plants:

poor, imprecise construction techniques,

poor choice of materials due to inexperienced contractors and consultants

unsatisfactory technology

inadequate repairs and maintenance

Improper mixing of feed stock and over or under feeding of the plant


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biogas technology - ahk...

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