The biogas and bio-diesel dual fuel technology is more concerned with the rural need. For an equal power output of each of the diesel and dual fuel engines, the performance results were evaluated.
INTRODUCTION
Motivation
Greenhouse gas emissions from diesel engines are due to the use of fossil diesel fuel. Lower diesel fuel usage will undoubtedly improve GHG emissions from diesel engines.
H ratio
- Dual Fuel Concept
- Fuel Selection
- Objectives of the Present Investigation
- Thesis Organization
Maximum replacement of fossil petroleum diesel fuel by using biodiesel as pilot ignition in dual fuel mode. CDM potential study of gaseous fuel used in the CI diesel engine during dual fuel operation.
LITERATURE REVIEW AND SCOPE OF RESEARCH
The Gas Diesel Engine
- History
- Engine modification
- The combustion process
However, the combustion processes in gas-smoked dual-fuel engines using pilot injection have been identified to occur in five stages as shown in Figure 2.3. This effect is not visible with the dual fuel combustion processes, as pre-oxidation of the gaseous fuel starts before pilot fuel injection.
Dual Fuel Diesel Engine – Prospects
- Effect of load (a) Combustion
- Effect of speed (a) Combustion
- Effect of pilot fuel mass
- Effect of engine compression ratio (a) Combustion
- Effect of intake manifold conditions (a) Combustion
- Effect of type of gaseous fuel (a) Combustion
- Effect of pilot fuel quality
Selim (2004) investigated the effects of fuel injection timing of a dual-fuel diesel engine. Selim (2004) investigated the effects of the amount of gaseous fuel in a dual-fuel diesel engine.
Availability Analysis of IC Engines
Second law analysis provides insight into when and where available energy is lost or destroyed in the engine system. These findings help reduce availability loss to improve engine performance in terms of efficiency and power output (Kumar et al., 2004). From the point of view of the second law, the combustion of hydrogen showed qualitatively different from the combustion of hydrocarbon fuels.
Scope of the Work
It has been found from several published literatures that dual fuel operations behave differently with variations in operating and design parameters. Again, the characteristics of a dual fuel engine such as efficiency, ignition delay and emissions vary greatly due to differences in fuel composition. Furthermore, the impact of changes in the design and operating parameters of the dual-fuel system in terms of system losses can also be evaluated.
Summary
Researchers have suggested that dual-fuel mode with gaseous fuels should be used to mitigate greenhouse gas emissions from diesel engines. To solve this problem, the present contribution decides to carry out a systematic experimental investigation using gaseous fuels under dual-fuel operation mode. The conventional dual fuel (CDF) system is one of the methods used in this work.
The Engine Test Bed
Fuel Supply System
- Gaseous fuel
- Liquid fuel
Instrumentation on the Engine Setup
- Engine performance measurement
- Air and gas flow measurement
- Temperature measurement
- Emission measurement
The flue gas compositions were analyzed using a multi-component analyzer based on the chemical and infrared cell technique. These samples were monitored in a flue gas analyzer system for direct reading of CO, CO2, NO, NO2 and hydrocarbon (HC) emissions. The resolution, accuracy, and range of these gas measurements for the Quintox Make Kane Flue Gas Analyzer are shown in Table 3.2.
Engine Conversion Methodology
- Biogas operation
- Syngas–diesel operation
This typical laboratory arrangement of gas storage and supply equipment for biogas dual fuel operation is shown in Fig. The circuit diagram of the add-on gas installation in the basic diesel engine for dual-fuel operation with syngas gas is shown in Fig. The details of the laboratory setup for the synchronized gas Diesel dual fuel operation is shown in Fig.
Experimental Procedures
- Baseline tests
- Biogas dual fuel tests
- Syngas–diesel dual fuel tests
- Experiment repeatability
- Analysis procedure
- Uncertainty analysis
A homogeneous mixture of gas and air from the carburetor was then drawn into the cylinder to participate in dual-fuel combustion through the engine manifold. A homogeneous mixture of gas and air from the carburetor was then sucked into the cylinder to participate in the combustion of the dual fuel. For steady-state dual-fuel operation, the same manual input parameters as described for the baseline tests were again entered into the computer software program for efficiency and combustion results.
Summary
Performance parameters were measured three times according to the experimental design for both diesel and dual fuel modes and averaged for each operating point. The formulas used in the various performance and combustion parameter calculations of the basic and dual fuel modes are illustrated in Appendix A. The uncertainties associated with the diesel and dual fuel engine performance calculations were evaluated using perturbed techniques. sequential (Kline and McClintock, 1953; Moffat, 1982).
BIOGAS DUAL FUEL ENGINE EXPERIMENTS
- Experimental Design
- Performance Parameters
- Combustion Parameters
- Emission Characteristics
- Summary
The BSECs of both dual fuel modes were higher than those of the diesel mode for all. In this process, both dual fuel modes set higher exhaust gas temperatures (about 40 to 700 C) than that of the diesel mode (Fig. 4.5). However, CO2 emission in diesel mode was lower compared to both dual fuel modes.
THERMODYNAMIC ANALYSIS OF BIOGAS DUAL FUEL ENGINE OPERATION
Availability Analysis
This caused a reduction in both the fuel availability and work output of the dual fuel modes. This is due to the higher exhaust gas availability loss from the dual fuel operations. It can be noted that the maximum exergy efficiency of dual fuel modes (about 26%) is higher than the energy efficiency of base diesel engine (about 21%).
Summary
It is a combined effect of reduction of combustion irreversibility and increase in the maximum temperature of the cycle, which caused the efficiency gains. Although biodiesel has a lower energy capacity than diesel, the presence of oxygen content improved combustion at higher loads. Thus there was only a 2% decrease in maximum exergy efficiency for bio-diesel pilot in the diesel case.
SYNGAS–DIESEL DUAL FUEL ENGINE EXPERIMENTS
- Experimental Design
- Performance Results
- Combustion Characteristics
- Emission Characteristics
- Summary
This was due to the limited syngas flow (up to the engine misfire condition) for the dual fuel combustion. Heat release rates for dual fuel modes were higher than for diesel mode for the entire load range. HC emission increased with syngas dual fuel operation compared to diesel mode due to incomplete combustion of fuel gas.
THERMODYNAMIC ANALYSIS OF SYNGAS–DIESEL ENGINE OPERATION
Availability Analysis
At low loads (20% and 40%), the ash availability of dual fuel mode was very miserable compared to diesel mode (Fig. 7.7). The highest ash availability was found in the case of diesel mode compared to all the tested dual fuel modes for the entire load range. It was reported in Chapter 6 that the syngas dual-fuel operations produced higher exhaust gas temperature compared to diesel mode for the entire load range (Fig. 6.3).
Summary
Chapter – 8
CLEAN DEVELOPMENT MECHANISM POTENTIAL INVESTIGATION OF THE DUAL FUEL OPERATIONS
- The Clean Development Mechanism
- CDM Analysis of Biogas Dual Fuel Operations
- CDM Analysis of Syngas Dual Fuel Operations
- Summary
Biogas-fueled dual-fuel operations produced higher concentrations of CO2 emissions compared to diesel mode for the entire load range (Fig. 4.18). Therefore, only increases in CO emissions during biogas dual-fuel operations in diesel mode are considered for the CDM analysis. Beyond these loads, both biogas dual-fuel operations showed relatively lower CO emissions than the diesel mode.
Chapter – 9
CONCLUSIONS AND FUTURE SCOPE
Contribution of the Present Work
- Biogas dual fuel operations
- Syngas dual fuel operations
In general, dual fuel operations can save friction than that of diesel mode. Moreover, the heat release rate of dual fuel modes is reduced compared to the diesel mode. The following conclusions can be drawn from extensive emission measurements of the syngas dual fuel operations.
Application Potential
This shows that hydrogen is an effective gaseous fuel in a diesel engine under dual fuel operation. It can be achieved for target gas dual fuel modes by accessing, mainly, about 8 to 17% of the availability loss of the fuel exhaust gas. However, industrial and power generation uses can switch from methane to biogas/syngas dual fuel mode without major problems.
Scope for Future Work
Dual fuel mode showed poor thermal efficiency due to (mainly) less energy conversion during operation. Thus, a waste exhaust gas heat recovery system can be added with the dual fuel engine operation. At low load, dual fuel operation revealed a maximum reduction in efficiency compared to diesel mode.
ASME Journal of Gas Turbine and Power Engineering, Vol. 2001) 'Experimental Investigations on a Jatropha Oil Methanol Dual Fuel Engine'. International Journal of Hydrogen Energy, Vol. 2004) 'Experimental studies on energy utilization in a single cylinder diesel engine'. International Journal of Hydrogen Energy, Vol. 1995) 'Knocking Characteristics of Dual-Fuel Engines Fueled with Hydrogen Fuel'.
Appendix – A
Engine Performance Analysis Procedure
Efficiency Calculation
It is determined using the liquid fuel mass flow rate in liquid fuel mode m&Lf (kg/s) and the pilot fuel mass flow rate in dual fuel mode m&pf (kg/s). xiv) Stoichiometric air-fuel ratio( )λ. The relative amounts of oxygen enrichment and fuel dilution can be quantified by the stoichiometric mixture fraction. It depends on the calorific value of the fuel used and the stoichiometric need for air for its combustion.
Combustion Analysis
The energy density or energy content in the engine cylinder determines the power developed in that cylinder. By taking diesel as fuel in a diesel engine, the calculation of its energy density is obtained as indicated below.
Appendix – B
Design and Dimensioning of Gas Carburetor
Distance between gas inlet and the inlet to the engine manifold = 400 mm
The designed T-joint with the gas nozzle protruding into the gas carburetor, according to the input data of the base engine, is presented in Figure B1 with complete dimensions. Target Intake manifold cross-section, m2 Agn Nozzle cross-section, m2 Agc Gas carburetor cross-section, m2 Cim Collector suction speed. Cgn Gas nozzle speed, m/s dim Intake manifold diameter, mm dgn Fuel-gas nozzle diameter, mm Lgc Gas carburetor length, m n Number of cycles per minute Vair Volumetric air intake, m3/s Vs Engine cubic volume, m3 Vgc Volume of gas carburetor, m3 Nomenclature.
Appendix – C
Measurement Uncertainty Analysis
The uncertainty in the measurement of thermal efficiency of dual fuel mode is estimated.
Appendix – D
Thermodynamic Analysis Calculation
Energy Analysis
The physical property of the exhaust gas (Cpeg) is determined from the energy balance of the exhaust gas calorimeter. The amount of the uncounted losses is determined by performing an energy balance and is given by, Quncounted =Qin− ( Pshaft+ Qcw+ Qeg) , kW (D6).
Availability Analysis
The physical property of the exhaust gas (Reg) is determined based on the energy balance of the exhaust gas calorimeter and the products of complete combustion of the diesel fuel. The uncounted availability destruction is determined based on the availability balance as. destroyed in shaft cw e.g. D12). T4 Water outlet temperature calorimeter, K T5 Engine exhaust gas temperature, K (or) . Exhaust gas inlet temperature calorimeter, K T6 Exhaust gas outlet temperature calorimeter, K Symbols.
LIST OF PUBLICATIONS
Journals
Conferences
