EXPERIMENTAL STUDIES ON BIOGAS PRODUCTION AND ITS UTILIZATION IN A DIRECT INJECTION DIESEL ENGINE RUN ON DUAL FUEL MODE A THESIS Submitted by DEBABRATA BARIK (Roll No: 511ME120) In Partial Fulfilment of the Requirement for the Degree of DOCTOR OF PHILOSOPHY DEPARTMENT OF MECHANICAL ENGINEERING NATIONAL INSTITUTE OF TECHNOLOGY ROURKELA ROURKELA-769008 (INDIA) NOVEMBER 2016 EXPERIMENTAL STUDIES ON BIOGAS PRODUCTION AND ITS UTILIZATION IN A DIRECT INJECTION DIESEL ENGINE RUN ON DUAL FUEL MODE A THESIS Submitted by DEBABRATA BARIK (Roll No: 511ME120) In Partial Fulfilment of the Requirement for the Degree of DOCTOR OF PHILOSOPHY Under the Supervision of PROF. S. MURUGAN DEPARTMENT OF MECHANICAL ENGINEERING NATIONAL INSTITUTE OF TECHNOLOGY ROURKELA ROURKELA-769008 (INDIA) NOVEMBER 2016 Department of Mechanical Engineering National Institute of Technology Rourkela Rourkela-769008 India CERTIFICATE This is to certify that the thesis entitled “Experimental studies on biogas production and its utilization in a direct injection diesel engine run on dual fuel mode” being submitted by Mr. Debabrata Barik for the award of Ph.D. degree is a record of bonafide research carried out by him in the Department of Mechanical Engineering, National Institute of Technology, Rourkela, under my supervision. It is also certified that to the best of my knowledge the work reported here in, does not form a part of any other thesis or dissertation on the basis of which a degree or award was conferred on an earlier occasion for this or any other candidate. Place: NIT Rourkela Supervisor Date: (Prof. S. Murugan) Associate Professor Department of Mechanical Engineering National Institute of Technology Rourkela Rourkela- 769008, India Dedicated to My Beloved Parents And My Wife Susmita (Gelhi) ACKNOWLEDGEMENT Completion of work with a lot of hurdles put off all joys of life, because it brings the real ecstasy in the life. This may not happen without a continuous support of my supervisor. I would like to take the opportunity to express my humble gratitude and deep regards to my supervisor, Prof. S. Murugan, Associate Professor, Department of Mechanical Engineering, for his flawless guidance, monitoring and continuous motivation for the completion of the thesis. The regular counselling, and lessons for life given by him shall help me to proceed properly in a long journey of my life. I take this opportunity to express my deep sense of gratitude to Prof. Animesh Biswas, Director, NIT Rourkela for providing required infrastructural facilities. I would also like to express my heartfelt thanks to Prof. S.K. Sarangi, Ex-Director, NIT Rourkela for his indirect support by providing a good ambience and necessary facilities for carrying out the research. I express my sincere thanks to Prof. S.S. Mohapatra, HOD, Department of Mechanical Engineering, NIT Rourkela for providing me the necessary facilities in the department. I take this opportunity to express my deep sense of gratitude to my Doctoral Scrutiny Committee members, Prof. S.S. Mohapatra (Chairman) and Prof. A. Satapathy, Department of Mechanical Engineering, Prof. R.K. Singh and Prof. A. Kumar, Department of Chemical Engineering, for their constant encouragement and valuable suggestions while carrying out my research. The completion of this research work could not have been accomplished without the support of my research colleagues, Dr. R. Prakash, Dr. Pritinika Behera, Dr. Dulari Hansdah, Dr. Arun Kumar Wamankar, Mr. Abhishek Sharma, Mr. Harishankar Bendu, and Mrs. Kapura Tudu. I express my appreciation for their in debt help and useful ideas related to the improvement and completion of the research work. I am also thankful to Mr. N.P. Barik, Mr. Ramakrishna Mandal and Mr. N.K. Bisoi for their timely help and cooperation in completing the experimental work. This work is also the outcome of the blessing guidance and support of my father Mr. Charchil Kumar Barik, mother Mrs. Urmila Barik, my wife Mrs. Susmita Samal, brother Mr. Satyabrata Barik, and sister Mrs. Pradiptyimayi Barik. I would like to thank them for their great support, patience and unconditional love and care during my good and bad times. Last but not the least, there may be many who remain unacknowledged in this humble note of gratitude and there are none who remain unappreciated. Above all, I owe it all to Almighty God for granting me the wisdom, health and strength to undertake this research work and enabling me to its completion. (Debabrata Barik) ABSTRACT Biodiesel is considered as one of the potential liquid alternative fuels in many countries in the world. It is produced from edible and non-edible oils, animal fat, and algae by the transesterification process. In India, Karanja (Pongamia pinnata) a non-edible oil seed is considered as a potential feedstock for biodiesel production. The de-oiled cakes of Karanja seed obtained from expeller units are of no use, and are disposed in the open. The disposal of such non edible oil cake in the open and land fill generates various anthropogenic gases, and may increase the global warming potential (GWP). The organic matters contained in these de-oiled cakes can be converted to useful energy by adopting a proper waste-to-energy conversion process. Hence, an attempt was made in this investigation to use the Karanja seed cake (SCK) as a potential feedstock for producing biogas by anaerobic digestion, and the produced biogas was proposed as an alternative fuel for CI engines. Initially, biogas was produced from four different proportions of SCK mixed with cattle dung (CD) in small scale rectors, to study the different parameters effecting the biogas production. The SCK-CD was mixed in the proportion of 75:25, 50:50, 25:75, and 0:100 in percentage on a mass basis, and the mixtures were denoted as S1, S2, S3, and S4 respectively. Important parameters, such as the pH, temperature, hydraulic retention time (HRT), and carbon/nitrogen ratio (C/N) were evaluated and analyzed. The results indicated that the sample S3 gave the best result, in comparison with the other samples, and the methane (CH4) and carbon dioxide (CO2) contents in the biogas were found to be about 73% and 17% respectively. The sample S3 was chosen for producing biogas in a large scale floating drum digester. The biogas obtained from the floating drum digester was stored in a gas bag and then characterized for its physiochemical properties, to ensure its application as a gaseous alternative fuel for CI engine. For ensuring its usage as an alternative fuel in a CI engine, it was tested in a single cylinder, four stroke, air cooled, direct injection (DI) diesel engine developing a power of 4.4 kW at a rated speed of 1500 rpm. The engine was modified to operate on the dual fuel mode. In the first module, the experimental results obtained from the diesel, KME, and dual fuel engine operated with diesel/biodiesel-biogas were validated by a three zone modeling using MATLAB. Combustion parameters, such as peak cylinder pressure, and ignition delay, and emission parameters, such as NO and smoke emission were validated. The validation i indicated that there was a deviation of only about 2-3% between the theoretical and experimental results. After the modeling work experimental investigation on the engine was performed. Two groups (A and B) of experimental modules were proposed to assess the dual fuel engine’s behavior. In group A, two experimental modules were proposed with diesel-biogas dual fuel. In the first module, diesel was used as an injected fuel (pilot) for initiating combustion, and biogas was inducted at four different flow rates in the suction of the engine, varying from 0.3 kg/h to 1.2 kg/h in steps of 0.3 kg/h. The combustion, performance and emission parameters of the engine were evaluated, analyzed and compared with those of diesel operation of the same engine. It was observed that the engine exhibited a drop in brake thermal efficiency and increase in CO and HC emissions throughout the load spectrum. Further, tests were conducted to determine the optimum injection timing of the pilot fuel in the diesel-biogas dual fuel mode, when the engine was operated at the optimum biogas flow rate of 0.9 kg/h. The injection timing of diesel (pilot fuel) was advanced to a maximum of 4.5 oCA in steps of 1.5 oCA, from the original injection timing of the engine. The engine behavior in terms of the combustion, performance and emissions was determined, and compared with those of the diesel-biogas dual fuel operation. Based on the experimental results, the advanced injection timing of 26 oCA was chosen as the optimum injection timing for the pilot injection. The data obtained with the diesel-biogas dual operation with the injection timing of 26 oCA were considered as reference data for further investigations in this study. After conducting experiments with the diesel-biogas, a few attempts were made in group B to run the engine only on two different renewable fuels (biodiesel and biogas) that were obtained from a single source of feedstock. In group B, as the first module, biodiesel was used as an injected (pilot) fuel instead of diesel and biogas was used as an inducted fuel. In this operation, biogas was inducted at different flow rates varying from 0.3 kg/h to 1.2 kg/h at regular intervals of 0.3 kg/h in the suction of the engine. From the results, it was observed that the ignition delay was reduced by about 2-4 oCA for the biodiesel-biogas dual fuel operation from that of the optimized diesel-biogas operation (26 oCA pilot fuel injection timing with biogas at 0.9 kg/h) at full load. In the second module, the injection timing of the pilot fuel (biodiesel) was advanced to a maximum of 4.5 oCA at regular intervals of 1.5 oCA and retarded to 1.5 oCA, from that of the original injection timing.