Sridhar G - Profile on Academia.edu (original) (raw)
Papers by Sridhar G
Biomass Derived Energy Carriers as Fuels in Engines and Fuel Cells
cgpl.iisc.ernet.in
This paper reviews the use of biomass for power generation using IC engines or fuel cells. The di... more This paper reviews the use of biomass for power generation using IC engines or fuel cells. The different types of biomass and common features among them are examined. Their use in power generation is reviewed and gasification has been identified as a ...
This paper presents experimental results of a study on the feasibility of making highly densified... more This paper presents experimental results of a study on the feasibility of making highly densified fuel block from agro residues that could be used for applications such as domestic cooking and barbecuing. A strategy had been adopted to determine the best suitable raw materials which meet both the criteria of performance and economy. In this regard several experiments were conducted with various raw materials in different proportions and it was found that fuel block composed of 40% biomass, 40% charcoal powder, 15% binder and 5% oxidizer fulfills the requirement of performance as well as economy. The unique geometry of this kind of fuel block (cylindrical one with a number of holes extending from top to bottom unlike traditional biomass briquette with single or no holes) helps in smokeless operation with reasonably steady thermal output. The geometry of the fuel block is so designed that it operates in partially premixed mode of combustion thus leading to better combustion and thereby lower emission. A typical fuel block for cooking weighing about 700-800g provides a thermal output of 1.5 kWth, with a burn time of 1.5 hours. Water boiling tests have indicated a thermal efficiency in the range of 55-58%.
Experimental and Modeling Aspects of Producer Gas Engine
ABSTRACT
Biomass gasification is environmentally benign and holds large promise for the future. The resear... more Biomass gasification is environmentally benign and holds large promise for the future. The research on producer gas engines commenced about a decade ago at Indian Institute of Science, Bangalore and today IISc and Cummins India Limited are partnering in developing and deploying producer gas engines. There are nearly 5 MWe power plants installed in the country and gained a cumulative experience of over 60,000 hours. Cummins India Limited is now offering producer gas engines in India backed with all commercial warranties coupled with the gasification technologies developed at the Indian Institute of Science. A range of gas engines up to 250 kWe capacity has undergone rigorous testing. The trials include tests for gas quality on engine performance, power output, emission and engine's response to load changes. The gas engines currently adapted for power generation application are fitted with a patented producer gas carburetion system which ensures nearly constant air-to-fuel ratio at various load factors. The producer gas engine power plants are serving applications like captive power, grid linked independent power and for distributed power generation. Some of these plants have been closely monitored and reliability studies conducted by the engine manufacturer. The studies indicate the wear of the engine's components assessed at the end of 5000 hours of operation are well within limits when compared to natural gas engine.
Torrefaction of Bamboo
Bamboo is a fast growing fibrous plant grown in abundance in India. As a consequence to bamboo fl... more Bamboo is a fast growing fibrous plant grown in abundance in India. As a consequence to bamboo flowering, it becomes imperative to find additional ways and means of using bamboo within a short span of time. If not put to immediate use the one other way is to extend the shelf life of the bamboo. The current practices of bamboo usage can only consume a part of the excess bamboo generated thereby opening possibility for other usages. Torrefaction of bamboo is seen as one such possibility that apart from energy densification makes the product resistant to fungal attack. Under one of funded project, torrefaction of bamboo has been successfully attempted on a kiln of 1 ton/day input capacity. Prior to conceiving the design of the kiln, basic studies have been conducted between 180 and 350 °C temperature. Furthermore torrefied bamboo has been characterized for calorific value and elemental balance. Based on the analysis it is found that there is an enhancement in energy density by 20% agai...
Theory to Practice, 2014
The work on thermo-chemical conversion of biomass was initiated at the Institute with the financi... more The work on thermo-chemical conversion of biomass was initiated at the Institute with the financial support from the Karnataka State Council for Science and Technology in 1981. During the first five years, one of the key question addressed was: Can a 3.7 kWe gasifier be built to produce engine consistent quality gas from woody biomass -even though small systems are prone to unfavorable thermal conditions? Studies showed that this question could be answered in the positive. The period 1985-90 was characterized by the demonstration of the possibility of new technologies that emerged from innovations in the laboratory. Soon there was a need to address requests for medium capacity systems. An automated 100-kWe gasifier with data acquisition system was set up at Port Blair. This system operated from 1990 led to several modifications and improved versions. The period 1990 -1995, was studded with 'crossing several milestones' related to 'technology improvement' and device longevity. The problems addressed during this period related to enhancing reactor life using ceramics. These efforts led to emergence of landmark reactor technology -rammed mass technology and hard high allumina tile face. The period of 1995 to 2000 was characterized by great interest from the Ministry of Non-conventional Energy Sources (MNES) and some interest from international groups, broadening the biomass feedstock types, adaptation to various type of engines, etc. The principal questions addressed were: Can feed stock range be enhanced to include other agro residues and urban solid waste. Can turbo-charged engines be run on producer gas without any technical problems? Can the issues related to gas engines be understood and technology elements built here. These led improving the scientific base. In doing so, many scientific questions were tackled. This period was also characterized by scientific developments involving, (a) modeling of combustion of individual biomass in specific geometric like sphere, (b) reactor as thermo-chemical device, (c) reactor design, (d) producer gas as a combustible medium, (e) physics of flame propagation vis-à-vis smooth burning in a high compression engines, heat balance and combustion in CI and SI engines has led to better science and engineering. This vast experience has enabled evolving, designing; field-testing and installing a large number of open top reburn gasification systems from 3 kW -1 MWe. Technological improvements on the reactor were accompanied by improvements in the gasifier subsystems also. Manufacturing process also has been examined to ensure good quality assurance. These studies have led to, a. interpreting gasification process as a two staged combustion process b. using a staged conversion process to achieve clean combustion-(high efficiency and low pollutant emission) c. adapting technology to low grade fuels like, agro wastes (sugar cane trash, agro residues), weeds (ipomea with high alkaline ash) and poorly segregated urban solid wastes.
Development of a Combustor to burn raw producer gas
Fuel Processing Technology, 2014
ABSTRACT
1 . India an oil -importing country, with nearly 70% of its population living in half million vil... more 1 . India an oil -importing country, with nearly 70% of its population living in half million villages and hamlets across the country and rich in bio -resources is ideally suited for biomass-based technologies. The Ministry of Non - conventional Energy Sources (MNES) has taken the initi- ative to develop research groups within India for techno - logy and manpower
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2006
A zero-dimensional modelling study has been conducted using wrinkled flame theory for flame propa... more A zero-dimensional modelling study has been conducted using wrinkled flame theory for flame propagation to understand the in-cylinder pressure behaviour with time in a reciprocating internal combustion engine. These are compared with experiments conducted on the engine operated on biomass derived from producer gas and air mixture. The required inputs on the laminar burning velocity and turbulence parameters are obtained from separate studies. The data related to laminar burning velocity for producer gas and air mixture at thermodynamic conditions typical of unburned mixture in an engine cylinder were obtained from one-dimensional flame calculations. The turbulence parameters were obtained by conducting a three-dimensional computational fluid dynamics study on a bowl-in-piston geometry to simulate motored or non-firing conditions. The above mentioned data were used in the zero-dimensional model to make pressure-time (p-θ) computation over the complete engine cycle, for a range of tes...
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2005
This paper discusses computational results concerning the laminar burning velocity of a biomass-d... more This paper discusses computational results concerning the laminar burning velocity of a biomass-derived producer gas and air mixture at pressures and temperatures typical of the unburned mixture in a reciprocating engine. The computations are based on solving conservation equations describing laminar one-dimensional, multicomponent, chemically reacting, and ideal gas mixtures that have been formulated by earlier researchers. Based on a number of calculations at varying initial pressures and temperatures, and equivalence ratios, an expression for estimating the laminar burning velocity with the recycled gas mass fraction has been obtained. Also, the effect of varying amounts of recycled gas on the burning velocity has been determined. These data on laminar burning velocities will be useful in predicting the burnrate in a spark ignition (SI) engine fuelled with a producer gas and air mixture.
Energy for Sustainable Development, 1996
the pulverisable fuels; accordingly, the same gasifier is able to successfully gasify sawdust and... more the pulverisable fuels; accordingly, the same gasifier is able to successfully gasify sawdust and sugarcane trash. Some issues related to handling sugarcane trash are also discussed. The treatment of the ash/residue is in the dry mode and therefore, the requirement of water is comparable to that in wood gasifiers and is much less than in Chinese fixed bed gasifiers. Another important aspect of the study is the measurement of the NOx in the engine exhaust which has shown that the NOx level for the dual-fuel mode is one-eighth of that in diesel-alone mode over the entire power range up to full load.
… http://cgpl. iisc. ernet. in/site …, 2006
st thomas college of engineering and technol… 183 PUBLICATIONS 3,247 CITATIONS SEE PROFILE All in... more st thomas college of engineering and technol… 183 PUBLICATIONS 3,247 CITATIONS SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
On the operation of a high pressure biomass gasifier with gas turbine
15th European …, 2007
ABSTRACT: Gas turbine operations with liquid and gaseous fossil fuels are an established route fo... more ABSTRACT: Gas turbine operations with liquid and gaseous fossil fuels are an established route for power generation. Use of low calorific value fuel like producer gas in gas turbine is not well established and currently there are no Gas turbines designed for this fuel. This ...
Proceedings of 15th …, 2007
Biomass gasification technology offers a cost effective option of power generation at power level... more Biomass gasification technology offers a cost effective option of power generation at power levels up to 3 MWe, for a wide variety of applications such as captive power in industry, grid linked independent power producer and distributed power generation. Today this technology is being utilized for power generation applications at a number of industrial sites in India and abroad. In India there are nearly 6 MWe equivalent power plants which are based on the state-of-the-art IISc's (Indian Institute of Science) open top re-burn down draft biomass gasification technology. One among this is installed as an Independent Power Producer (IPP), which is the largest fixed bed gasification system in the country. The The grid linked power plant operates on a range of feed stocks such as coconut shell, Julifora Prosopis and converts into electricity. Apart from electricity the plant also generates value added product namely partially activated carbon. The specific biomass consumption is measured to be within 1.0 ± 0.1 kg/kWh with an overall efficiency of 24-26%. It is also found to be environmentally benign in terms of emissions; NOx and CO levels are found to be much lower than most of the existing emissions norms of various countries.
14th European …, 2005
In the recent times issues like the Green House Gas (GHG) emission reduction and carbon-trading t... more In the recent times issues like the Green House Gas (GHG) emission reduction and carbon-trading through Clean Development Mechanism (CDM) have gained large prominence as a part of climate change. Biomass gasification is one such technology which is environmentally benign and holds large promise for the future. These technologies are currently being utilized for power generation applications at a number of industrial sites in India and abroad. In India there are nearly 4 MWe equivalent power plants which are based on IISc's open top reburn down draft biomass gasification technology. In the field of power generation, there has been substantial effort in the development of producer gas engine; systematic experimental and modeling studies followed by long duration field monitoring. As a part of this effort, a gas carburetor has been designed for producer gas fuel and forms a part of the power package. The essential requirements of gas conditioning equipment are packaged to meet the engine quality gas as a power plant. Currently there are more than 3.0 MWe equivalent gas engines operating in the field; of this one is deployed in an Energy Service Company (ESCO), which sells green electricity to a textile industry. The company is located at Metupalyam in South India, near the city of Coimbatore. The power plant is configured with a 150 kg/hr gasifier coupled with a turbo charged after cooled Cummins make (GTA855G) gas engine. The plant is also provided with an effluent treatment plant and an engine-waste-heat based biomass drier. The plant commissioned in September 2003 has successfully completed over 7500 hours of operation, generating about 0.7 million units, thus saving a net CO2 of about 0.7 million Tons against a fossil fuel technology. The plant operates on a continuously to meet the end use requirement over 275 hours non stop operations hours of operation. The power plant utilizes a weed namely Julifora Prosopis which is abundantly available in the southern part of India and converts into green energy; additionally generates value added product namely partially activated carbon -Iodine no. of 400 -450. The paper reports specific biomass consumption and engine emission monitored over long duration. The specific biomass consumption is measured to be within 1.1 ± 0.1 kg/kWh with an overall efficiency of 22-24%. It is also found to be environmentally benign in terms of emissions; NOx and CO levels are found to be much lower than most of the existing emissions norms of various countries including the United States and European Union. The paper also highlights results from other installations using this technology.
Biomass and Bioenergy, 2003
The paper addresses case studies of a low temperature and a high temperature industrial heat requ... more The paper addresses case studies of a low temperature and a high temperature industrial heat requirement being met using biomass gasiÿcation. The gasiÿcation system for these applications consists of an open top down draft reburn reactor lined with ceramic. Necessary cooling and cleaning systems are incorporated in the package to meet the end use requirements. The other elements included are the fuel conveyor, water treatment plant for recirculating the cooling water and adequate automation to start, shut down and control the operations of the gasiÿer system. Drying of marigold ower, a low temperature application is considered to replace diesel fuel in the range of 125-150 l h −1. Gas from the 500 kg h −1 , gasiÿer system is piped into the producer gas burners ÿxed in the combustion chamber with the downstream process similar to the diesel burner. The high temperature application is for a heat treatment furnace in the temperature range of 873-1200 K. A 300 kg h −1 of biomass gasiÿer replaces 2000 l of diesel or LDO per day completely. The novelty of this package is the use of one gasiÿer to energize 16 burners in the 8 furnaces with di erent temperature requirements. The system operates over 140 h per week on a nearly nonstop mode and over 4000 h of operation replacing fossil fuel completely. The advantage of bioenergy package towards the economic and environmental considerations is presented.
Biomass and Bioenergy, 2001
This paper uncovers some of the misconceptions associated with the usage of producer gas, a lower... more This paper uncovers some of the misconceptions associated with the usage of producer gas, a lower calorific gas as a reciprocating engine fuel. This paper particularly addresses the use of producer gas in reciprocating engines at high compression ratio (17 : 1), which hitherto had been restricted to lower compression ratio (up to 12 : 1). This restriction in compression ratio has been mainly attributed to the auto-ignition tendency of the fuel, which appears to be simply a matter of presumption rather than fact. The current work clearly indicates the breakdown of this compression ratio barrier and it is shown that the engine runs smoothly at compression ratio of 17 : 1 without any tendency of auto-ignition. Experiments have been conducted on multi-cylinder spark ignition engine modified from a production diesel engine at varying compression ratios from 11:5 : 1 to 17 : 1 by retaining the combustion chamber design. As expected, working at a higher compression ratio turned out to be more efficient and also yielded higher brake power. A maximum brake power of 17:5 kWe was obtained at an overall efficiency of 21% at the highest compression ratio. The maximum de-rating of power in gas mode was 16% as compared to the normal diesel mode of operation at comparable compression ratio, whereas, the overall efficiency declined by 32.5%. A careful analysis of energy balance revealed excess energy loss to the coolant due to the existing combustion chamber design. Addressing the combustion chamber design for producer gas fuel should form a part of future work in improving the overall efficiency.
A 20 kW reciprocating engine is operated using producer gas derived from a modern open top downdr... more A 20 kW reciprocating engine is operated using producer gas derived from a modern open top downdraft re-burn biomass gasifier that has been evaluated by rigorous laboratory performance testing over several hundred hours. The engine is operated at varying compression ratio (CR) from 11.5 to 17.0 and ignition timings from 30 to 6° before Top Centre (TC). The engine – alternator system is characterised for its performance by the simultaneous measurement of gas and airflow rates, gas composition (on-line), emission levels and power delivered. It is also instrumented to obtain the in-cylinder behaviour in the form of pressure-crank angle (p – θ) diagram to assess the thermodynamic behaviour of the engine. Three-dimensional (3-D) simulation of the flow field in the combustion chamber (involving piston-bowl arrangement) through the cycle up to the start of the combustion is used to obtain inputs on the turbulence intensity (u′) and length scale (l T ) for the modelling of the flame propaga...
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2004
This paper discusses the detailed three-dimensional modelling of a reciprocating engine geometry ... more This paper discusses the detailed three-dimensional modelling of a reciprocating engine geometry comprising a flat cylinder head and a bowl-in-piston combustion chamber, simulating the motoring or non-firing conditions. The turbulence is modelled using a standard k-1 model and the results are compared against experimental results from the literature. Computed velocity profiles at time steps close to top centre (TC) are presented. The effect of squish and reverse squish becomes significant in a high compression ratio reciprocating engine. This enhanced fluid movement during a reverse squish regime could have an effect on burn rate, particularly in a spark ignition engine fuelled with biomass-derived producer gas, which has optimum ignition timing close to TC.
Biomass Derived Energy Carriers as Fuels in Engines and Fuel Cells
cgpl.iisc.ernet.in
This paper reviews the use of biomass for power generation using IC engines or fuel cells. The di... more This paper reviews the use of biomass for power generation using IC engines or fuel cells. The different types of biomass and common features among them are examined. Their use in power generation is reviewed and gasification has been identified as a ...
This paper presents experimental results of a study on the feasibility of making highly densified... more This paper presents experimental results of a study on the feasibility of making highly densified fuel block from agro residues that could be used for applications such as domestic cooking and barbecuing. A strategy had been adopted to determine the best suitable raw materials which meet both the criteria of performance and economy. In this regard several experiments were conducted with various raw materials in different proportions and it was found that fuel block composed of 40% biomass, 40% charcoal powder, 15% binder and 5% oxidizer fulfills the requirement of performance as well as economy. The unique geometry of this kind of fuel block (cylindrical one with a number of holes extending from top to bottom unlike traditional biomass briquette with single or no holes) helps in smokeless operation with reasonably steady thermal output. The geometry of the fuel block is so designed that it operates in partially premixed mode of combustion thus leading to better combustion and thereby lower emission. A typical fuel block for cooking weighing about 700-800g provides a thermal output of 1.5 kWth, with a burn time of 1.5 hours. Water boiling tests have indicated a thermal efficiency in the range of 55-58%.
Experimental and Modeling Aspects of Producer Gas Engine
ABSTRACT
Biomass gasification is environmentally benign and holds large promise for the future. The resear... more Biomass gasification is environmentally benign and holds large promise for the future. The research on producer gas engines commenced about a decade ago at Indian Institute of Science, Bangalore and today IISc and Cummins India Limited are partnering in developing and deploying producer gas engines. There are nearly 5 MWe power plants installed in the country and gained a cumulative experience of over 60,000 hours. Cummins India Limited is now offering producer gas engines in India backed with all commercial warranties coupled with the gasification technologies developed at the Indian Institute of Science. A range of gas engines up to 250 kWe capacity has undergone rigorous testing. The trials include tests for gas quality on engine performance, power output, emission and engine's response to load changes. The gas engines currently adapted for power generation application are fitted with a patented producer gas carburetion system which ensures nearly constant air-to-fuel ratio at various load factors. The producer gas engine power plants are serving applications like captive power, grid linked independent power and for distributed power generation. Some of these plants have been closely monitored and reliability studies conducted by the engine manufacturer. The studies indicate the wear of the engine's components assessed at the end of 5000 hours of operation are well within limits when compared to natural gas engine.
Torrefaction of Bamboo
Bamboo is a fast growing fibrous plant grown in abundance in India. As a consequence to bamboo fl... more Bamboo is a fast growing fibrous plant grown in abundance in India. As a consequence to bamboo flowering, it becomes imperative to find additional ways and means of using bamboo within a short span of time. If not put to immediate use the one other way is to extend the shelf life of the bamboo. The current practices of bamboo usage can only consume a part of the excess bamboo generated thereby opening possibility for other usages. Torrefaction of bamboo is seen as one such possibility that apart from energy densification makes the product resistant to fungal attack. Under one of funded project, torrefaction of bamboo has been successfully attempted on a kiln of 1 ton/day input capacity. Prior to conceiving the design of the kiln, basic studies have been conducted between 180 and 350 °C temperature. Furthermore torrefied bamboo has been characterized for calorific value and elemental balance. Based on the analysis it is found that there is an enhancement in energy density by 20% agai...
Theory to Practice, 2014
The work on thermo-chemical conversion of biomass was initiated at the Institute with the financi... more The work on thermo-chemical conversion of biomass was initiated at the Institute with the financial support from the Karnataka State Council for Science and Technology in 1981. During the first five years, one of the key question addressed was: Can a 3.7 kWe gasifier be built to produce engine consistent quality gas from woody biomass -even though small systems are prone to unfavorable thermal conditions? Studies showed that this question could be answered in the positive. The period 1985-90 was characterized by the demonstration of the possibility of new technologies that emerged from innovations in the laboratory. Soon there was a need to address requests for medium capacity systems. An automated 100-kWe gasifier with data acquisition system was set up at Port Blair. This system operated from 1990 led to several modifications and improved versions. The period 1990 -1995, was studded with 'crossing several milestones' related to 'technology improvement' and device longevity. The problems addressed during this period related to enhancing reactor life using ceramics. These efforts led to emergence of landmark reactor technology -rammed mass technology and hard high allumina tile face. The period of 1995 to 2000 was characterized by great interest from the Ministry of Non-conventional Energy Sources (MNES) and some interest from international groups, broadening the biomass feedstock types, adaptation to various type of engines, etc. The principal questions addressed were: Can feed stock range be enhanced to include other agro residues and urban solid waste. Can turbo-charged engines be run on producer gas without any technical problems? Can the issues related to gas engines be understood and technology elements built here. These led improving the scientific base. In doing so, many scientific questions were tackled. This period was also characterized by scientific developments involving, (a) modeling of combustion of individual biomass in specific geometric like sphere, (b) reactor as thermo-chemical device, (c) reactor design, (d) producer gas as a combustible medium, (e) physics of flame propagation vis-à-vis smooth burning in a high compression engines, heat balance and combustion in CI and SI engines has led to better science and engineering. This vast experience has enabled evolving, designing; field-testing and installing a large number of open top reburn gasification systems from 3 kW -1 MWe. Technological improvements on the reactor were accompanied by improvements in the gasifier subsystems also. Manufacturing process also has been examined to ensure good quality assurance. These studies have led to, a. interpreting gasification process as a two staged combustion process b. using a staged conversion process to achieve clean combustion-(high efficiency and low pollutant emission) c. adapting technology to low grade fuels like, agro wastes (sugar cane trash, agro residues), weeds (ipomea with high alkaline ash) and poorly segregated urban solid wastes.
Development of a Combustor to burn raw producer gas
Fuel Processing Technology, 2014
ABSTRACT
1 . India an oil -importing country, with nearly 70% of its population living in half million vil... more 1 . India an oil -importing country, with nearly 70% of its population living in half million villages and hamlets across the country and rich in bio -resources is ideally suited for biomass-based technologies. The Ministry of Non - conventional Energy Sources (MNES) has taken the initi- ative to develop research groups within India for techno - logy and manpower
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2006
A zero-dimensional modelling study has been conducted using wrinkled flame theory for flame propa... more A zero-dimensional modelling study has been conducted using wrinkled flame theory for flame propagation to understand the in-cylinder pressure behaviour with time in a reciprocating internal combustion engine. These are compared with experiments conducted on the engine operated on biomass derived from producer gas and air mixture. The required inputs on the laminar burning velocity and turbulence parameters are obtained from separate studies. The data related to laminar burning velocity for producer gas and air mixture at thermodynamic conditions typical of unburned mixture in an engine cylinder were obtained from one-dimensional flame calculations. The turbulence parameters were obtained by conducting a three-dimensional computational fluid dynamics study on a bowl-in-piston geometry to simulate motored or non-firing conditions. The above mentioned data were used in the zero-dimensional model to make pressure-time (p-θ) computation over the complete engine cycle, for a range of tes...
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2005
This paper discusses computational results concerning the laminar burning velocity of a biomass-d... more This paper discusses computational results concerning the laminar burning velocity of a biomass-derived producer gas and air mixture at pressures and temperatures typical of the unburned mixture in a reciprocating engine. The computations are based on solving conservation equations describing laminar one-dimensional, multicomponent, chemically reacting, and ideal gas mixtures that have been formulated by earlier researchers. Based on a number of calculations at varying initial pressures and temperatures, and equivalence ratios, an expression for estimating the laminar burning velocity with the recycled gas mass fraction has been obtained. Also, the effect of varying amounts of recycled gas on the burning velocity has been determined. These data on laminar burning velocities will be useful in predicting the burnrate in a spark ignition (SI) engine fuelled with a producer gas and air mixture.
Energy for Sustainable Development, 1996
the pulverisable fuels; accordingly, the same gasifier is able to successfully gasify sawdust and... more the pulverisable fuels; accordingly, the same gasifier is able to successfully gasify sawdust and sugarcane trash. Some issues related to handling sugarcane trash are also discussed. The treatment of the ash/residue is in the dry mode and therefore, the requirement of water is comparable to that in wood gasifiers and is much less than in Chinese fixed bed gasifiers. Another important aspect of the study is the measurement of the NOx in the engine exhaust which has shown that the NOx level for the dual-fuel mode is one-eighth of that in diesel-alone mode over the entire power range up to full load.
… http://cgpl. iisc. ernet. in/site …, 2006
st thomas college of engineering and technol… 183 PUBLICATIONS 3,247 CITATIONS SEE PROFILE All in... more st thomas college of engineering and technol… 183 PUBLICATIONS 3,247 CITATIONS SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
On the operation of a high pressure biomass gasifier with gas turbine
15th European …, 2007
ABSTRACT: Gas turbine operations with liquid and gaseous fossil fuels are an established route fo... more ABSTRACT: Gas turbine operations with liquid and gaseous fossil fuels are an established route for power generation. Use of low calorific value fuel like producer gas in gas turbine is not well established and currently there are no Gas turbines designed for this fuel. This ...
Proceedings of 15th …, 2007
Biomass gasification technology offers a cost effective option of power generation at power level... more Biomass gasification technology offers a cost effective option of power generation at power levels up to 3 MWe, for a wide variety of applications such as captive power in industry, grid linked independent power producer and distributed power generation. Today this technology is being utilized for power generation applications at a number of industrial sites in India and abroad. In India there are nearly 6 MWe equivalent power plants which are based on the state-of-the-art IISc's (Indian Institute of Science) open top re-burn down draft biomass gasification technology. One among this is installed as an Independent Power Producer (IPP), which is the largest fixed bed gasification system in the country. The The grid linked power plant operates on a range of feed stocks such as coconut shell, Julifora Prosopis and converts into electricity. Apart from electricity the plant also generates value added product namely partially activated carbon. The specific biomass consumption is measured to be within 1.0 ± 0.1 kg/kWh with an overall efficiency of 24-26%. It is also found to be environmentally benign in terms of emissions; NOx and CO levels are found to be much lower than most of the existing emissions norms of various countries.
14th European …, 2005
In the recent times issues like the Green House Gas (GHG) emission reduction and carbon-trading t... more In the recent times issues like the Green House Gas (GHG) emission reduction and carbon-trading through Clean Development Mechanism (CDM) have gained large prominence as a part of climate change. Biomass gasification is one such technology which is environmentally benign and holds large promise for the future. These technologies are currently being utilized for power generation applications at a number of industrial sites in India and abroad. In India there are nearly 4 MWe equivalent power plants which are based on IISc's open top reburn down draft biomass gasification technology. In the field of power generation, there has been substantial effort in the development of producer gas engine; systematic experimental and modeling studies followed by long duration field monitoring. As a part of this effort, a gas carburetor has been designed for producer gas fuel and forms a part of the power package. The essential requirements of gas conditioning equipment are packaged to meet the engine quality gas as a power plant. Currently there are more than 3.0 MWe equivalent gas engines operating in the field; of this one is deployed in an Energy Service Company (ESCO), which sells green electricity to a textile industry. The company is located at Metupalyam in South India, near the city of Coimbatore. The power plant is configured with a 150 kg/hr gasifier coupled with a turbo charged after cooled Cummins make (GTA855G) gas engine. The plant is also provided with an effluent treatment plant and an engine-waste-heat based biomass drier. The plant commissioned in September 2003 has successfully completed over 7500 hours of operation, generating about 0.7 million units, thus saving a net CO2 of about 0.7 million Tons against a fossil fuel technology. The plant operates on a continuously to meet the end use requirement over 275 hours non stop operations hours of operation. The power plant utilizes a weed namely Julifora Prosopis which is abundantly available in the southern part of India and converts into green energy; additionally generates value added product namely partially activated carbon -Iodine no. of 400 -450. The paper reports specific biomass consumption and engine emission monitored over long duration. The specific biomass consumption is measured to be within 1.1 ± 0.1 kg/kWh with an overall efficiency of 22-24%. It is also found to be environmentally benign in terms of emissions; NOx and CO levels are found to be much lower than most of the existing emissions norms of various countries including the United States and European Union. The paper also highlights results from other installations using this technology.
Biomass and Bioenergy, 2003
The paper addresses case studies of a low temperature and a high temperature industrial heat requ... more The paper addresses case studies of a low temperature and a high temperature industrial heat requirement being met using biomass gasiÿcation. The gasiÿcation system for these applications consists of an open top down draft reburn reactor lined with ceramic. Necessary cooling and cleaning systems are incorporated in the package to meet the end use requirements. The other elements included are the fuel conveyor, water treatment plant for recirculating the cooling water and adequate automation to start, shut down and control the operations of the gasiÿer system. Drying of marigold ower, a low temperature application is considered to replace diesel fuel in the range of 125-150 l h −1. Gas from the 500 kg h −1 , gasiÿer system is piped into the producer gas burners ÿxed in the combustion chamber with the downstream process similar to the diesel burner. The high temperature application is for a heat treatment furnace in the temperature range of 873-1200 K. A 300 kg h −1 of biomass gasiÿer replaces 2000 l of diesel or LDO per day completely. The novelty of this package is the use of one gasiÿer to energize 16 burners in the 8 furnaces with di erent temperature requirements. The system operates over 140 h per week on a nearly nonstop mode and over 4000 h of operation replacing fossil fuel completely. The advantage of bioenergy package towards the economic and environmental considerations is presented.
Biomass and Bioenergy, 2001
This paper uncovers some of the misconceptions associated with the usage of producer gas, a lower... more This paper uncovers some of the misconceptions associated with the usage of producer gas, a lower calorific gas as a reciprocating engine fuel. This paper particularly addresses the use of producer gas in reciprocating engines at high compression ratio (17 : 1), which hitherto had been restricted to lower compression ratio (up to 12 : 1). This restriction in compression ratio has been mainly attributed to the auto-ignition tendency of the fuel, which appears to be simply a matter of presumption rather than fact. The current work clearly indicates the breakdown of this compression ratio barrier and it is shown that the engine runs smoothly at compression ratio of 17 : 1 without any tendency of auto-ignition. Experiments have been conducted on multi-cylinder spark ignition engine modified from a production diesel engine at varying compression ratios from 11:5 : 1 to 17 : 1 by retaining the combustion chamber design. As expected, working at a higher compression ratio turned out to be more efficient and also yielded higher brake power. A maximum brake power of 17:5 kWe was obtained at an overall efficiency of 21% at the highest compression ratio. The maximum de-rating of power in gas mode was 16% as compared to the normal diesel mode of operation at comparable compression ratio, whereas, the overall efficiency declined by 32.5%. A careful analysis of energy balance revealed excess energy loss to the coolant due to the existing combustion chamber design. Addressing the combustion chamber design for producer gas fuel should form a part of future work in improving the overall efficiency.
A 20 kW reciprocating engine is operated using producer gas derived from a modern open top downdr... more A 20 kW reciprocating engine is operated using producer gas derived from a modern open top downdraft re-burn biomass gasifier that has been evaluated by rigorous laboratory performance testing over several hundred hours. The engine is operated at varying compression ratio (CR) from 11.5 to 17.0 and ignition timings from 30 to 6° before Top Centre (TC). The engine – alternator system is characterised for its performance by the simultaneous measurement of gas and airflow rates, gas composition (on-line), emission levels and power delivered. It is also instrumented to obtain the in-cylinder behaviour in the form of pressure-crank angle (p – θ) diagram to assess the thermodynamic behaviour of the engine. Three-dimensional (3-D) simulation of the flow field in the combustion chamber (involving piston-bowl arrangement) through the cycle up to the start of the combustion is used to obtain inputs on the turbulence intensity (u′) and length scale (l T ) for the modelling of the flame propaga...
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2004
This paper discusses the detailed three-dimensional modelling of a reciprocating engine geometry ... more This paper discusses the detailed three-dimensional modelling of a reciprocating engine geometry comprising a flat cylinder head and a bowl-in-piston combustion chamber, simulating the motoring or non-firing conditions. The turbulence is modelled using a standard k-1 model and the results are compared against experimental results from the literature. Computed velocity profiles at time steps close to top centre (TC) are presented. The effect of squish and reverse squish becomes significant in a high compression ratio reciprocating engine. This enhanced fluid movement during a reverse squish regime could have an effect on burn rate, particularly in a spark ignition engine fuelled with biomass-derived producer gas, which has optimum ignition timing close to TC.