Scaling of biogas plants

Scaling of biogas plants

Scaling of biogas plants

Introduction
To calculate the scale of a biogas plant, certain characteristic parameters are used. These are as
follows for simple biogas plants
Daily fermentation slurry arisings (Sd),
-  Retention time (RT),
-  Specific gas production per day (Gd), which depends on the retention time and the feed material.

The following additional concepts and parameters are also used in the theoretical literature:

-  Dry matter (DM). The water content of natural feed materials varies. For this reason the solids or dry matter content of the feed material is used for exact scientific work (see table in Fig. 2).

-  Organic dry matter (ODM or VS). Only the organic or volatile constituents of the feed
material are important for the digestion process. For this reason, only the organic part of the dry matter content is considered.

-  Digester loading (R). The digester loading indicates how much organic material per day has to be supplied to the digester or has to be digested. The digester loading is calculated in kilograms of organic dry matter per cubic metre of digester volume per day  (kg ODM/m³/day). Long retention times result in low digester loadings. In a simple biogas plant, 1.5 kg/m3/day is already quite a high loading. Temperature-controlled and
mechanically stirred large-scale plants can be loaded at about 5 kg/m3/day. If the, digester loading is too high, the pH falls. The plant then remains in the acid phase because there is more feed material than methane bacteria
Example:
Calculation of digester loading
Digester volume (VD): 48001 (4.8 m³) Retention time (RT): 80 days
Daily amount of fermentation slurry (Sd): 60 kg
Proportion of organic matter: 5 %

R = 5x60/100 x 4.8 = 0.625 kg/m3/day

Retention time (RT or t) indicates the period spent by the feed material in the digester. It is chosen by economic criteria. The retention time is appreciably shorter than the total time required for complete digestion of the feed material.

Specific gas production may be quoted for the amount of fermentation slurry, the dry matter, content or only the organic dry matter. In practice, it represents the gas production of a specific feed material in a specific retention time at specific digester temperatures.

Degree of digestion is measured as a percentage. It indicates the amount of gas obtained as aproortion of total specific gas production. The difference from 100% indicates the proportion of feed material which is not yet fully digested. In simple biogas plants, the degree of digestion is about 50 %. This means that half the feed material is not used.
Biochemical oxygen demand (BOD) is an important parameter in effluent treatment. It indicates the degree of pollution of effluents or sewage. The BOD is a measure of the amount of oxygen consumed by bacteria in biological purification.

Scaling of the digester
The size of the digester - the digester volume (VD) - is determined by the length of the retention time (RT) and by the amount of fermentation slurry supplied daily (Sd). The amount of fermentation slurry consists of the feed material (e.g., cattle dung) and the mixing water.

 Example:
30 l dung + 30 l water = 60 l fermentation slurry

The digester volume is calculated by the formula

VD(l) = Sd(l/day) x RT (days)

Example:
Daily supply (Sd): 60 l
Retention time (RT): 80 days
Digester volume (VD):
60 l/day x 80 days = 4800 1 (4.8 m³)

For a specific digester volume and a known amount of fermentation slurry, the actual retention time is given by the formula

RT(days) = VD(l) -:-Sd(l/day)
Example:
Digester volume (VD): 4800 l
Daily supply (Sd): 60 l/day
Retention time (RT):
4800 l -:- 60 l/day = 80 days

If the digester size is given and a specific retention time is required, the daily amount of feed is
calculated by the formula

Sd (l/day) = VD (l) . RT(days)

Example:

Digester volume (VD): 4800 l
Retention time (RT): 80 days
Daily fermentation slurry requirement (Sd):
4800 l -:- 80 days = 60 l/day

If a biogas plant is loaded not daily but at relatively long intervals, the daily supply (Sd) decreases although the fermentation slurry proportion (S) remains the same. The retention time is correspondingly prolonged.

Example:

Digester volume (VD): 4800 l
Fermentation slurry proportion (S): 60 l
1. Daily loading, i.e. Sd= S = 60 l/day:
Retention time (RT):
4800l -:- 60 l/day = 80 days
2. Loading every other day, i.e.
Sd=S 2=30Q/day:
Retention time (RT):
4800 l -:- 30 £/day = 160 days
3. Loading twice a week, i.e.
Sd= S x 2/7 = 17.2 l/day:
Retention time (RT):
4800 l -:- 17.2 l/day = 279 days

Biogas Plant In Sialkot Pasrur Village Fatah Gujjaran Photos

Biogas Plant In Sialkot Pasrur Village Fatah Gujjaran Photos

Biogas Plant Design and Construction Consultancy by Dr Ashraf Sahibzada

Biogas Plant Design and Construction Consultancy by Dr Ashraf Sahibzada in Urdu / Punjabi / Hindi Videos

Video 1 

GOBAR GAS SARA E AALAMGIR DR.ASHRAF SAHIBZADA



DR.ASHRAF SAHIBZADA (a native of BHADDAR GUJRAT) is a world renowned Pakistani Agricultural Scientist. He extends free advisory service on all aspects of agriculture & livestock to famers of Pakistan as a noble deed. His Help no. is +92-333-5121879 and Email: a.sahibzada@hotmail.com He is currently residing in Islamabad.

Video 2
BIO GAS CALL FROM DOHA QATAR DR.ASHRAF SAHIBZADA



Video3
BIOGAS MANDI BAHAUDDIN PUNJABI DR.ASHRAF SAHIBZADA



Video 4

Biogas Information urdu



Video 5
Biogas Plant manufacturer contact number Pakistan



Video 6



DR.ASHRAF SAHIBZADA Bhaddar world famed Pakistani Agricultural Scientist replies to farmers quarries on all aspects of agriculture & livestock. He extends free advisory service to famers of Pakistan as a noble deed. His cell no. is 03335121879. You can call him from 1200 to 1400 hours daily and join in recording PAKISTANI ZARAT Program and watch on You Tube. His native village is Bhaddar Tehsil Kharian District Gujrat but resides in Islamabad. If anybody wants to meet him in person then before proceeding first check his availability.

Video | Biogas Plant

Biogas Plant Videos

Plastic Dome Biogas Plant

In this video man collecting the animal dung and adding some water and put in to plastic dome like bio gas plant and he showing stove where gas burns



Biological. West material i.e caw dung , vegetable west , food west as well agriculture west converted in to high pressure biogas. In absence of oxygen this process is accrue and biological partial converted in to high quality CH4 ( methane gas) generally it called BIOGAS.

Video 2
Storing biogas in a plastic trash bag



Description
I don't know why I didn't do this before. It simplifies things significantly. I had seen old black and white photos from China from the 60s and 70s where farmers stored biogas in large plastic bags in the rafters of their barns, but had chosen the path of trying to build hard tank gas holders. A case of over engineering and a lack of confidence in the safety of biogas I think. Or sheer stupidity. I had built Salchica plastic bag bio-digesters with Yair Teller and Beverly Goodman and Ilona Muallam and others at the Arava institute of Environmental Studies in Israel and visited Dominic Wanjahia's Simply Logic plastic biodigesters in Kenya so I was very familiar with the principle, but I ended up buying expensive robust plastic and PVC material (pond liner grade stuff) because I was going to use it for both the digester and the gas storage and knew it had to be strong enough to last. But today I reasoned "wait a minute -- I have my IBC tanks to make the biogas, I just need a simpler way to store it and pressurize it." And voila, a simple plastic garbage bag with a tank adapter and a valve, sealed with duct tape, using a blanket or throw rug for the pressure, does the trick. Simple and elegant and cheap, it obviates the need for a floating tank or other kind of storage system. Go on and try this one at home! I got 20 minutes of cooking from a single trash bag -- enough to make two bowls of soup.

Video 3

Biogas Plant Experiment

Biogas plant under construction in Poland

Biogas Plant Under Construction in Poland

Vechta, Germany based organic waste to biogas technology supplier, Weltec Biopower has begun construction of a 2.4 MW biogas plant in Darzyno, Poland.

The company said that once complete the anaerobic digestion facility will be used to produce biogas from a mixture of liquid manure maize and, which will be supplied by farmers from the vicinity. The plant will also process potato waste of a chip manufacturer.

Four tanks with a capacity of 5000 cubic meters each provide sufficient space for the digestate.

The company explained that the substrates at the plant - located 80km from Danzig - will be fed into the four 4438 cubic meters stainless-steel fermenters via the four storage tanks and a 50 cubic metres dosing feeder.

The facility will be operated by utility company NEWD, which has previously only operated wind farms, but is now developing the country's first biogas plant with Weltec's polish subsidiary, Weltec Polska.

According to Weltec, the conditions in Poland are ideal for generating biogas, with an agricultural area of around 18.5 million hectares - 1.5 million hectares more than Germany. Liquid manure from cattle, pigs, poultry and other renewable raw materials are readily available as substrate for biogas plants.

The company added that the infrastructure conditions in Poland are also ideal, with subsidised decentralised power and heat generation, and a highly developed infrastructure for the transport of gas and district heat.

Furthermore, Weltec said that Poland's government is currently implementing policies for the development of decentralised energy supply through laws and directives - especially for biomass and biogas.

Through the 'Biogas Development Programme 2010-2020', Poland is aiming to have at least one agricultural biogas plant installed in every municipality by 2020 - there are approximately 2500 municipalities.`

source: www.waste-management-world.com

A Biogas Research Institute will be established at the University of Agriculture Faisalabad

A Biogas Research Institute will be established at the University of Agriculture Faisalabad

A Biogas Research Institute will be established at the University of Agriculture Faisalabad (UAF) in collaboration with Biogas Institute of Ministry of Agriculture, (BIOMA) and People’s Republic of China. This was revealed during a meeting of UAF scientists with 4-member Chinese delegation headed by Ren Xiaobin, Deputy Director, Training and Information Research Centre BIOMA in New syndicate Hall of UAF here on Thursday.
UAF Vice Chancellor Dr Iqrar Ahmad welcomed the members of Chinese delegation and hoped that the proposed project would become a milestone for research and development activities in the field of renewable energy in the country. Dr Iqrar lauded the efforts of Punjab Chief Minister Muhammad Shahbaz Sharif for the promotion of research and development activities in the energy sector. He maintained that due to the absence of appropriate R&D mechanism, Pakistan could not have exploited its potential in renewable energy sector. He said that during last 35 years more than 7,000 biogas plants were set up but due to non-availability of sufficient human resource the system could not be sustained.
Mr Ren Xiaobin while addressing the scientists, said that Pakistan had great potential to generate renewable energy particularly through biogas. He urged the scientists to adopt latest technology in order to develop a sustainable environment friendly energy production in the country.
He said that BIOMA had set up 65 projects in various countries and provided training facility to 560 workers and experts. He added that BIOMA would provide all sort of technical assistance for the establishment of proposed Research Institute. Delegation also visited various sites of alternate energy.

Research Paper | Household Biogas Digesters

Household Biogas Digesters—A Review 

Karthik Rajendran *, Solmaz Aslanzadeh and Mohammad J. Taherzadeh 

School of Engineering, Universityof Borås, Borås 50190, Sweden;

E-Mails: Solmaz.Aslanzadeh@hb.se (S.A.); Mohammad.Taherzadeh@hb.se (M.J.T.)

*Author to whom correspondence should be addressed; E-Mail: Karthik.Rajendran@hb.se;

Tel.: +46-33-435-4855; Fax: +46-33-435-4008.

Received: 11 May 2012; in revised form: 27 July 2012 / Accepted: 30 July 2012 /

Published: 8 August 2012

Bio gas digester

Abstract:This review is a summary of different aspects of the design and operation of small-scale, household, biogas digesters. It covers different digester designs and materials used for construction, important operating parameters such as pH, temperature, substrate, and loading rate, applications of the biogas,the government policies concerning the use of household digesters, and the social and environmental effects of the digesters. Biogas is a value-added product of anaerobic digestion of organic compounds. Biogas production depends on different factors including: pH, temperature, substrate, loading rate, hydraulic retention time (HRT), C/N ratio, and mixing. Household digesters are cheap, easy to handle, and reduce the amount of organic  household waste. The size of these digesters varies between 1 and 150 m3. The common designs include fixed dome, floating drum, and plug flow type. Biogas and fertilizer obtained at the end of anaerobic digestion could be  used for cooking, lighting, and electricity.

Keywords:biogas; household digesters; bioenergy; waste management; fixed dome digesters; floating drum digesters; plug flow digesters

1. Introduction
Due to the increasing prices of fossil fuels and taxes on energy sources, finding alternative, clean
and economical sources of energy has nowadays become a major concern for households’ and nations’
economies. In addition, economic prosperity and quality of life, which are linked in most countries to
per-capitaenergy consumption, is a great determinant and indicator of economical development
Energy demand is a critical reason for extensive climate change, resource exploitation, and also
restricts the living standards of humans [5,6].  By the time fuel and fertilizer reaches rural areas, the end price is relatively expensive due to high  transport costs, leaving people to find alternative resources other thanoil [7]. Starke [8] reported wood  as the traditional source of fuel to produce energy for domestic purposes for 2.5 billion people in Asia. Many of the rural communities in developing countries are forced torely on the traditional energy  sources such as firewood, dung, crop residues, and paraffin. These traditional methods are often expensive and/or time-consuming [9–11]. Cooking accounts for 90% of energy consumption in the households of developing countries [12]. Furthermore, access to electricity in rural areas is relatively scarce [13]. Biogas is a substitute for firewood and cattle dung that can meet the energy needs of the rural population [14,15]. Biogas is a renewable source of energy that can be used as a substitute for natural gas or liquefied petroleum gas [16]. There are different models to assess the energy content of different energy sources, which includes water boiling test, controlled cooking test and kitchen performance test [17]. The energy content of 1.0 m3 of purified biogas is equal to 1.1 L of gasoline, 1.7 L of bioethanol, or 0.97 m3 of natural gas [16]. The application for rural and urban waste biogas production is widely spread. It is a challenge for engineers and scientists to build an efficient domestic digesters with the materials available, at the same time taking the local and economical considerations into the account. Although many digesters have been built, additional research and awareness are needed to meet the changing needs and conditions [18]. Biogas production can be carried out in very small reactors ranging from100-mL serum bottles in the lab up to 10,000 m3large digesters as normally used, for example, in Europe. This review deals with a summary of different household biogas digesters, their operating parameters, cost and materials used to build them, startup, and maintenance, the variety of applications employed, and associated social and environmental effects. 

 Biogas
Biogas, the metabolic product of anaerobic digestion, is a mixture of methane and carbon dioxide with small quantities of other gases such as hydrogen sulfide [19,20]. Methane, the desired component of biogas, is a colorless, blue burning gas used for cooking, heating,and lighting [21]. Biogas is a clean, efficient, and renewable source of energy, which can be used as a substitute for other fuels in order to save energy in rural areas [22]. In anaerobic digestion, organic materials are degraded by bacteria, in the absence of oxygen, converting it into a methane and carbon dioxide mixture. The digestate or slurry from the digester is rich inammonium and other nutrients used as an organic fertilizer [11,23–27]. Methane formation in anaerobic digestion involves four different steps, including hydrolysis, acidogenesis, acetogenesis, and methanogenesis. Different bacterial/archaea communities work in a syntrophic relationship with each other to form methane. In hydrolysis, complex carbohydrates, fats, and proteins are first hydrolyzedto their monomeric forms by exoenzymes and bacterial cellulosome. In the second phase (acidogenesis), monomers are further degraded into short-chain acids such as: acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, caprionic acid,lcohols, hydrogen, and carbon dioxide. During acetogenesis, these short-chain acids are converted into acetate, hydrogen, and carbon dioxide. In the last phase, methanogens convert the intermediates produced into methane and carbon dioxide. Almost one-third of methane formation is due to reduction of carbon dioxide by hydrogen

Download full research Paper Household Biogas Digesters