Bio Gas Systems

Hi, first of all I want to say something about Biogas. As the name shown in the title "Biogas", it is a gas which can be used for multiple purpose like- cooking, lighting . generation of electricity etc. in India this gas is called Gobar Gas. the meaning of the world Gobar is sheet of cow, bull. To produce the biogas it is necessary to iinstall a plant called " Bio-gas plant". It could be of various capacity 01 cu. mtrs to 06 cu. mtrs. for domestic bio-gas plants. the latest model for the plant is called DINBANDHU Model Bio-gas Plant. Similarly we can install big size bio-gas plants also like 25 cu. mtrs, 60 cu. mtrs, 85 cu. mtrs , depending on tye row material available.

House hold toilet linked biogas plant with mixed feed of animal dungGeneration and utilization of biogas from human wastes has three in one properties- it improves sanitation, makes available energy at low cost and better quality of manure for agriculture purposes. There is financial support from the Ministry of New and Renewable Energy , Government of India for implementing biogas plant in IndiaHowever, biogas plant solely based on human waste for a family is not economically viable option. Because the rate of biogas production per person use of toilet per day is only one cubic foot i.e., in a family having 5 users of toilet per day only 5 cft of biogas would be produced per day. Minimum requirement of biogas for cooking for 2 hours a day for a small family is about 40cft. However, it can be made profitable when mixed with cattle dung along with human wastes. Biogas from dung of 2 nos. of cattle when mixed with human wastes can cater the need of cooking for a small familyQuantity of biogas production from different feed materials · From animal dung- per animal per day around 10 kg dung is available. Gas production rate from dung is about 0.04 cubic meter per kg, i.e., per animal per day 0.4 cum gas is produced · From human waste per person per day 0.4 kg of waste is produced and gas production from per kg of human wastes is 0.10 cum · A total amount of biogas of one cum can be produced per day from a family having 4 members and 2 cattle heads. Utilizations of biogasOne cum of biogas per day can be utilized in a family as follows: · Cooking of 3-4 family members for two times a day · Mantle lamps (2nos.) can be used for 6 hours per night. Such mantle lamps gives illumination equivalent to 4o watt bulb at 220 volt of electricity. · Can run an engine of one Horse Power for 2 hours Manure value of sludge from biogas plantBesides biogas, the manure of the plant has much plant nutrient value. It is directly used for agriculture purpose. The following is the comparative value of plant nutrients ( N,P,K, value ) from biogas manure and other compost Sl.No. Name of constituent Nitrogen Phosphorus Potash 1 Compost Manure (%) 0.50-0.75 0.70-0.80 1.20-1.50 2 Biogas slurry(%) 1.30-1.50 0 .85-0.9 2 1.50-1.65 Design of biogas plantFor family size biogas plant there are basically two designs (1) Floating drum type popularly known as KVIC model and (2) Fixed dome type ,popularly know as Deenbandhu Model. In the KVIC model gas holder is made up of iron sheet( mild steel). During winter season when temperature fall down to 10 degree Celsius or so, this model ceases to function as the iron sheet gas holder acts as good conductor of heat and inner temperature of the digester also attains the same temperature. Secondly, this gas holder requires regular care and maintenance to prevent from getting worn out because of corrosion. It has short working life. Manufacturing of gas holder requires sophisticated workshop facility that is rarely fond in rural areas. Therefore , in rural or in urban areas the success rate of this model of biogas plant is far below the level of satisfactionDeenbandhu model.—This model is predominately found in India. It is complete brick structure. It is a permanent structure having almost nil operation and maintenance costs. There is no separate gas holder , biogas is stored inside plant through liquid displacement chamber.. The cost of Deenbandhu plant is lesser than the KVIC model Detail drawings of Deenbandhu Model of biogas plant of different capacities (1cum,2cum,3 cum and 4 cum per day gas production) are as follows.

Drawing of Deenbandhu model 1 cum per day gas production capacity

Materials required to construct different capacities of biogas plants

Maintenance of Deenbandhu Biogas PlantThe Deenbandhu plant is simple to .operate and handle as far as the beneficiaries are concerned. The following simple guidelines far general care and maintenance will increase the operational life and working efficiency of the Deenbandhu plant several folds. · The gate valve should be opened only when the gas has to. be actually used. · Before opening the valves, one must ensure that all the preparation far cooking have been made. This would avoid the unnecessary, wasteful consumption of gas. · The air injector should not be closed very tightly on the side of the burner. The inflow of the air should be adjusted properly in the injector · The outlet tank of the plant should never be left uncovered. In addition to the above, the daily, weekly, monthly, yearly and five yearly care and maintenance should be done as per the schedule given below. Maintenance and General CareDaily(i) Add dung slurry to the plant. Keep ratio of dung and water at 1:1. (ii) Clean gas burner.MonthlyCheck gas pipeline for leaks with a soap solution.Annually · Check for gas and water leaks and repair them. · Check gas pipelines and renew, if necessary. · ) At intervals of some years or when the plant shows signs of leakage, it should be com¬pletely emptied to renew the sealing and plastering of the inside portion of the plant. Take the necessary safety precautions when performing this task. Five Yearly · Empty the plant and clean the sludge and inorganic material from the bottom of the plant. · Give a thorough check to the entire gas distribution system for possible leakage. · Repaint the ceiling of the dome and gas storage chamber with black enamel paint. · Recharge (reload) the plant with fresh slurry Do's and Dont's · Select the size of the biogas plant depending on the quantity of dung available with the beneficiaries. · Install the biogas plant at a place near the kitchen as well as the cattle shed as far as possible. · Ensure that the outer side of the plant must be firmly compacted with soil. · Ensure that the plant is installed in an open space, and gets plenty of sunlight for the whole day, all round the year. · Feed the biogas plant with cattle dung and water mixture in the right proportion-add 1 part of cattle dung to 1 part of water by weight to make a homogeneous mixture · Ensure that the slurry (mixture of dung and water) is free from soil, straw, etc. · For efficient cooking, use good quality and approved burners and gas lamps. · Open the gas regulator cock only at the time of its actual use · Adjust the flame by turning the air regulator till a blue flame is obtained this will give maximum heat. · Light the match first before opening the gas cock. · Cover the top of the inlet and outlet tank opening with wooden, stone or RCC cover, to avoid accidental falling of cattle and children. · Purge air from all delivery lines allowing gas to flow for a while prior to first use. Dont's · Do not install a bigger size of biogas plant if one doesn't have sufficient cattle dung or any other feed-stock to be used for biogas production · Do not install the gas plant at a long distance from the point of gas utilisation to save the cost of pipeline and loss of biogas. · Do not install the plant under a tree, inside the house or under shade · Do not compact soil loosely around the plant; otherwise it may get damaged · Do not add more than the required quantity of either dung or water-doing so might affect the efficient production of gas. · Do not make digested slurry pit more than 1.0 m (3 ft) deep · Do not allow the scum to form in the digester; otherwise the production of gas will reduce · Do not leave the gas regulator (valve) open when the gas is not in use. · Do not inhale the biogas as it may be hazardous. · Do not allow soil or sand to enter into the digester. · Do not burn the gas directly, i.e. from the gas outlet pipe even for the testing purpose as it can be dangerous. · Do not use burner in the open; otherwise there will be considerable loss of heat. · Do not use the gas if the flame is yellow. Adjust the flame by the air regulator till it is blue in colour. Do not hurry to get gas after initial loading of slurry, as it may take 10-25 days for gas production in freshly loaded plants. No foreign material should be added. · Do not let any water accumulate in the gas pipeline; otherwise the required pressure of gas will not be maintained and the flame will sputte Precautions · Never allow gas pressure to build up in the dome over 1,000 mm water column; other¬wise the dome will be damaged. · Never inhale biogas. · Never allow any person to enter the gas plant when it has slurry inside to avoid accidental fells that may cause even death due to methane gas inside plant. For cleaning purpose open the gas valve for a day or two only then one should enter into plant.. · Always keep the openings of the outlet and inlet chambers firmly closed by putting stone or concrete covers on them; small animals or children can fall into the slurry accidentally and die due to suffocation Use of other organic wastes in biogas plant along with animal and human wastes. It has been observed that in rural and other areas biogas plants are not functional due to lack of sufficient feed materials. To have more biogas plant with available feed materials one can use kitchen waste, green leaves, water hyacinth, grass clippings, etc. after, proper chopping and mixing with cattle dung. Before it is fed into plant. Such mixed feed biogas plant has additive effect on gas production. Addition of organic matters containing a high percentage of nitrogen. increases the gas production and improves the quality of manure.Fixed-dome biogas plants have been set up at altitudes of around 2000 m inHimachal Pradesh and the hill districts of Uttar Pradesh. In Chhattisgarh CREDA is the nodel agency for all type of re-newable energy sources and the Deen-bandhu model biogas plants arte very successfull in chhattisgarh. Since dome is underground variation in atmospheric temperature has least effect on biogas production..

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