FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
PKUVlSIUNAk / COMPLETE SPECIFICATION (See section 10 and rule 13)

1. TITLE OF THE INVENTION
"A TRIPHASIC BIOMETHANATION PROCESS."
2. APPLICANT (a) NAME : GANGOTREE RESOURCE DEVELOPERS PVT.LTD.
NATIONALITY, : An Indian Company, registered under the provisions of the Companies Act, 1956 (c) ADDRESS : Durga,92/2,Erndwana,Gangote Path,
Opp.Kamala Nehru Park, Pune 411004 Maharashtra State, India..
3. PREAMBLE TO THE DESCRIPTION
PROVISIONAL
The following specjfieattondescribes the invention COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

The present invention relates to a triphasic biomethanation process. More particularly, it relates a triphasic biomethanation process wherein a commercially available biomass that is rich in starch or sugar is converted into a combustible mixture of methane and carbon dioxide using microbial consortia.
The present invention is directed towards a process through which conversion of starch or sugar into a combustible mixture of methane can be brought in an efficient, reliable and reproducible manner for producing clean gaseous fuel at a competitive cost.
The purpose of the present invention is to develop a mixture of methane that is used for cooking purposes or for generating electricity. This mixture can also be converted to purified methane and compressed as CNG for use in vehicles.
The object of the present invention is to facilitate generation of a source of energy on tap, from commercially available, renewable commodities in a cost effective manner.
The main aim of the present invention is to develop a process that makes it possible to generate biogas for kitchen fuels, electrical power or transportation from renewable biomass in a cost effective manner as in immediate future stocks of fossil fuel will run out and zero carbon emission based process offers great potential.
The scope of present invention is to develop a process wherein energy in the form of biogas is obtainable from readily available agricultural commodities at competitive generation cost.


PRIOR ART:
In the conventional method, the gasification of biomass is done by heating the biomass with a controlled air supply to produce a mixture of hydrogen and carbon monoxide. This mixture is combustible and can be burnt as a source of energy.
Alternatively, many waste materials such as cow dung, sewage, spent wash or other effluents, are microbially converted into a combustible mixture of methane and carbon dioxide that can be used as an energy source. This conversion involves the stages of hydrolysis of biomass, its conversion into short chain fatty acids and their further conversion into a mixture of methane and carbon dioxide. The three stages of conversion, each brought about microbiologically, are invariably brought about using a single reactor, although in rare cases, the third stage is separated from the first two. The waste materials are utilized as and when available and the conversion is primarily aimed at reducing the polluting load in an economical manner. In case of cow dung the presently operated single stage system is ideally designed for domestic use in rural areas.
DEFICIENCIES OF PRIOR ART:
1. That the thermal gasification of biomass is essentially used for ligneous materials. It uses a substantial part of the feed for generating heat that brings about the conversion of carbonaceous matter into a mixture of hydrogen and carbon monoxide. The conversion efficiency is low.


2. That the generation of biogas from industrial waste/cow dung suffers from the following drawbacks:
Presently available plants/processes combine the three stages of
microbial conversion in one (in rare cases two) reactor. The
conditions prevailing in the reactor are thus sub-optimal for each
set of microorganisms. This results in slowing down of the
conversion process.
In conditions of overloading of feeds, whereas the conversion to
short chain fatty acids keeps pace with the feed input, the
conversion to methane does not. This increases the acidity of the
system, destroys methane generating microorganisms and leads to
a further accumulation of acids. The system goes in a tailspin and
the reactor stops functioning.
Whereas the cow dung based biogas plants keep getting a fresh
supply of microorganisms (from fresh dung) continuously, such is
not the case with waste based or other feed based biogas plants.
Hence when these plants turn acid and stop functioning, the
microbial consortia need to be built up all over again causing long
shut down periods.
The relatively low concentration of the organic matter in the feed
drain out larger volumes at high loading factors. This results in
increased reactor volumes and high capital costs.
Use with starch -rich substrates frequently results in ethanol as an
end product under anaerobic conditions.
PRESENT INVENTION:
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the preferred embodiment. The
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present invention enables generation of a source of energy on tap, from commercially available, renewable commodities in a cost effective manner. This is brought about by incorporating the following:-
(a) The overall reaction is segregated into three distinct stages and conditions of air access, pH retention time; microbial consortia etc. are optimized separately for each stage.
(b) Microbial consortia for each stage are separately grown to target a given feed and are made readily available, to cut down gestation periods at start-up or while commissioning.
(c) The hydrolytic reaction, which is the first stage of the process, is speeded up by providing appropriate physical/enzymatic/microbial environment.
(d) The retention period is reduced by increasing the concentration of microorganisms, thereby cutting down the plant size and consequent capital costs. Further, the microbial consortia are so adjusted as to block the formation of ethanol.
(e) The acid generation stage is segregated from the methane generation stage. This enables a controlled entry of acid in the third stage. The methane generating microorganisms are active in this stage and these are susceptible to high acidity conditions.
(f) Feed concentration to the system is slightly raised. This reduces the volume of feed entering and leaving the system and concomitant loss of methane generating microorganisms with the effluent.
(g) The dependence on ready availability of feed is overcome by switching over to commercially available commodities.


The present invention is a process in which energy in the form of biogas is obtainable from readily available agricultural commodities at competitive generation costs. The major factor that has enabled the cost reduction is the reduction of retention time of the feed material in the reactor. This has reduced the capital cost of equipment. Another factor is an improvement in the overall conversion efficiency by segregation of the three stages and optimizing the process conditions.
The retention time has been cut down mainly by increasing the population of the microbial population in each of the three segregated stages of the process. In the first stage of hydrolytic breakdown of biomass, the microbial process is preceded by use of physical/enzymatic/microbial attack to make the feed more vulnerable.
The segregation of the overall process into three distinct stages has made it possible to analyze the conversion efficiency of each stage and readjust its input/output levels as also the microbial population that brings about the conversion. Separation of the group of microbial consortium that converts the short chain fatty acids to methane from the other two stages has made it possible to protect this very susceptible group from high acidity levels and exposure to aerobic conditions. That by suitably adjusting the concentration of the organic matter that is allowed to flow through the system, it has become possible to reduce the volume of the effluent and thereby the loss of methanogenic microorganisms from the third stage. This has, in turn, conserved the population of this group, which are the slowest growers of all. Building up an independent stock of these three groups of microbial consortia in a separate facility has made it possible to commission or restart a plant with a relatively short gestation period.
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The present invention relates to a triphasic biomethanation process which
comprises the steps of:
adding agricultural feed into first reactor tank;
gelatinizing the feed by heating to a temperature of 40° C to 90 ° C;
subjecting the feed to moist heat;
hydrolyzing the feed by adding atleast one enzyme or microbial population
capable of producing required enzymes and allowing to react for 1 to 24
hours;
adding hydrolysate from the first reactor tank into second reactor for
conversion into short chain fatty acids;
adding enriched microbial consortia to the hydrolysate in the second reactor;
heating the hydrolysate to a temperature between 30 ° C to 50 ° C with
occasional stirring for 30 hours to 72 hours;
adding acid rich mixture obtained from second reactor in third reactor;
adding methanogenic microorganisms to the acid rich mixture in third reactor;
and
heating the mixture to a temperature between 30 ° C to 50 ° C for 70 to 96
hours under anaerobic conditions to obtain a methane rich gas mixture being
not less than 500 liters per kilogram of starch or sugary substance in the feed
and the methane content of the gas so evolved is not less than 55% .
Detailed description
Detailed descriptions of the preferred embodiments are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or matter.


The process according to the present invention is segregated into three distinct stages and conditions of air access, pH retention time; microbial consortia etc. are optimized separately for each stage. The Microbial consortia for each stage are separately grown to target a given feed and are made readily available, to cut down gestation periods at start-up or while commissioning. Further, the hydrolytic reaction, which is the first stage of the process, is speeded up by providing appropriate physical/enzymatic/microbial environment. Further, the microbial consortia are so adjusted as to block the formation of ethanol. The acid generation stage is segregated from the methane generation stage. This enables a controlled entry of acid in the third stage. The methane generating microorganisms are active in this stage and these are susceptible to high acidity conditions. Feed concentration to the system is slightly raised. This reduces the volume of feed entering and leaving the system and concomitant loss of methane generating microorganisms with the effluent. The dependence on ready availability of feed is overcome by switching over to commercially available commodities.
According to the present invention, a triphasic biomethanation process for converting starch or sugary agricultural feed stock into a methane rich gas mixture comprises adding agricultural feed into the first reactor tank and subjecting it to moist heat. The temperature in the first reactor tank is maintained at 40 to 90 ° C. Further, atleast one enzyme or microorganism capable of producing the required enzyme, is added to the above-mentioned dissolved agricultural feed. The mixture of the feed and enzymes is allowed to react for a period of 1 to 24 hours in the first reactor.
The agricultural feed is preferably rich in starch or sugar. It is selected from the ones that are most suitable for a given plant location such as crude tapioca starch, maize powder, sorghum, sugarcane, rain damaged grains when available, high sugar containing palm saps, cakes left after extraction of non-edible oil seeds, starchy tubers of all kinds, etc. A preliminary analysis of the


agricultural feed helps in deciding the input level of the feed in the system and parameters for the first stage of attack.
The enzyme added maybe amylase, proteases, etc. The microorganisms added maybe Bacillus subtilis, Clostridium propionicum, etc.
Further, the hydrolysate obtained at the end of reaction from first reactor is added to the second reactor where it is converted into short chain fatty acids.
The hydrolysate is subjected to an enriched microbial consortium, specifically prepared for the hydrolysate of the particular feed. This consortium is specifically prepared for the particular feed as target and is enriched from natural microbial mixtures such as cow dung, sewage, etc. by a process of restricting its nutrition to the subject feed over a period of time. Once enriched the consortium is propagated and made available for deployment in the reactor. The reaction in the second reactor is carried out at a temperature between 30 ° C to 50 ° C for 24 to 72 hours along with occasional stirring.
The microorganisms for preparation of the enriched consortium may be selected from propagated from cowdung sewage or effluent ponds near industries using the identified feeds.
The acid rich mixture from the second reactor is introduced into the third reactor. The mixture maybe neutralized with lime during the first few days, if required. It is subjected to methanogenic microorganisms. The temperature is maintained between 30 ° C to 50 ° C for 70 to 96 hours and the mixture is stirred occasionally. The reactor is protected from exposure to oxygen in the air and monitored for acid accumulation.
The methane rich gas starts evolving by 24 hours. The gas so generated is not less than 500lit/kg of starchy/sugary substance in the feed and has


methane content of not less than 55%. It can be stirred suitably and used directly for burning or stripped of contaminating gases and used either as feed stock in internal combustion engines for power generation or compressed (CNG) and made available for use in vehicles.
The segregation of the overall process into three distinct stages has made it possible to optimize the conversion efficiency of each stage and readjust its input/output levels as also the microbial population that brings about the conversion. Separation of the group of microbial consortium that converts the short chain fatty acids to methane from the other two stages has made it possible to protect this very susceptible group from high acidity levels and exposure to aerobic conditions. That by suitably adjusting the concentration of the organic matter that is allowed to flow through the system, it has become possible to reduce the volume of the effluent and thereby the loss of methanogenic microorganisms from the third stage. This has, in turn, conserved the population of this group, which are the slowest growers of all. Building up an independent stock of these three groups of microbial consortia in a separate facility has made it possible to commission or restart a plant with a relatively short gestation period.
The process is versatile and can be carried out using any starch-rich or sugar-rich feed stock that is advantageous in a location
The triphasic biomethanation process for converting starch or sugary agricultural heed stock into a methane rich gas mixture is supported by quoting few examples, which are as follows:
Example No.1:-
One kilogram of karanja de-oiled cake was suspended in ten litre of water and subjected to the action of amylase followed by a protease at 70 degrees centigrade. After holding the feed at this temperature for one hour, it was cooled to 37 degrees centigrade and passed on to stage two of the system. The reactor


used for this stage contained a suitable enriched consortium of micro organisms capable of converting the hydrolysed organic matter into short chain fatty acids. The reactor was maintained at 37 +/- 2 degrees centigrade and stirred occasionally. This was followed by a similar addition on the following day. On the third day, ten litre of acid mixture was passed on to the third stage that was carried out in a similar reactor, held at 37 +/- 2 degrees centigrade and similarly stirred, that contained an enriched microbial consortium of methanogenic bacteria. This addition was repeated into the reactor on five successive days to fill up this reactor to 50 % of its capacity. Form the sixth day, ten litre of the reaction mixture from the third stage was discarded every day and was replenished with ten litre of acid mixture. The gas got generated daily, as a result of conversion in this stage, and was collected in a conventional manner and measured 550 litres comprising of 60% of methane. The whole process is repeated in a continuous fashion so that the system received one kilogram of cake every day and gave out not less than 500 litre of gas every day.
Example No. 2:-
One kilogram of tapioca starch is used as feed in place of deoiled Karanja Cake mentioned in example land the rest of the process was carried out in the same manner as in example no.1 except a small alteration in the mixture of enzymes used. The daily generation of gas in this system is not less than 620 litres comprising of 62% of methane.
Example No. 3:-
One kilogram of maize powder was used as feed in place deoiled Karanja Cake mentioned in example 1 and the process is repeated as in example 1 except that the enzyme ration is optimized to suit the analysis of maize and any un-reacted solid residue at the end of Stagel was removed and discarded. The daily generation of gas is not less than 580 litres comprising of not less that 60% of methane.


The system is quite versatile and will use any starch-rich or sugar-rich feed stock that is advantageous in a location. It is designed around the feedstock and employs microbial consortia and reaction conditions for each stage targeted for a given feed stock.
ADVANTAGES OF THE INVENTION:
1. It uses renewable starch -rich/sugary agro-products as feedstock to generate a combustible gas, in a cost effective manner.
2. It cut down start up or re-commissioning period for a plant.
3. It uses three segregated stages to bring about the conversion whereby reactions in each stage are carried in a highly efficient manner and under optimal conditions thereby substantially increasing efficiency and reducing plant size.
4. It prevents the formation of alcohol.


WE CLAIM:
1. A triphasic biomethanation process which comprises the steps of:
adding agricultural feed into first reactor tank;
gelatinizing said feed by heating to a temperature of 40° C to 90 ° C;
subjecting said feed to moist heat;
hydrolyzing said feed by adding at least one enzyme or microbial population
capable of producing required enzyme and allowing to react for 1 to 24 hours;
adding hydrolysate from the first reactor tank to second reactor for conversion
into short chain fatty acids;
adding enriched microbial consortia to said hydrolysate;
heating said hydrolysate to a temperature between 30 ° C to 50 ° C with
occasional stirring for 30 hours to 72 hours;
adding acid rich mixture obtained from second reactor to third reactor;
adding methanogenic microorganisms to said acid rich mixture in third
reactor; and
heating said mixture to a temperature between 30 ° C to 50 ° C for 70 to 96
hours under anaerobic conditions to obtain a methane rich gas mixture.
2. A triphasic biomethanation process as claimed in claim 1, wherein said agricultural feed is crude tapioca starch, maize powder, sorghum, sugarcane, rain damaged grains, high sugar containing palm saps, cakes left after extraction of non-edible oil and starchy tubers.
3. A triphasic biomethanation process as claimed in claim 1, wherein said enzymes added in first reactor are proteases, amylases, and lipases.


4. A triphasic biomethanation process as claimed in claims 1 to 3 substantially as herein described with reference to the foregoing description and examples.
Dated this 1st day of September 2005.

M.D. BHATE
(AGENT FOR APPLICANT)