part 1: overview of cogeneration and its status in asia - Fire

More documents

Recommendations

Info

6 Part I: Overview of cogeneration and its status in Asia economic factors. The extraction points of steam from the turbine could be more than one, depending on the temperature levels of heat required by the processes. Fuel Boiler Steam Process Turbine Steam Turbine (i) Back-Pressure Turbine (ii) Extraction-Condensing Turbine Fuel Boiler Process Condenser Figure 1.2 Schematic diagrams of steam turbine cogeneration systems Cooling Water Another variation of the steam turbine topping cycle cogeneration system is the extractionback pressure turbine that can be employed where the end-user needs thermal energy at two different temperature levels. The full-condensing steam turbines are usually incorporated at sites where heat rejected from the process is used to generate power. The specific advantage of using steam turbines in comparison with the other prime movers is the option for using a wide variety of conventional as well as alternative fuels such as coal, natural gas, fuel oil and biomass. The power generation efficiency of the cycle may be sacrificed to some extent in order to optimize heat supply. In backpressure cogeneration plants, there is no need for large cooling towers. Steam turbines are mostly used where the demand for electricity is greater than one MW up to a few hundreds of MW. Due to the system inertia, their operation is not suitable for sites with intermittent energy demand. 1.4.2 Gas turbine cogeneration systems Gas turbine cogeneration systems can produce all or a part of the energy requirement of the site, and the energy released at high temperature in the exhaust stack can be recovered for various heating and cooling applications (see Figure 1.3). Though natural gas is most commonly used, other fuels such as light fuel oil or diesel can also be employed. The typical range of gas turbines varies from a fraction of a MW to around 100 MW. Gas turbine cogeneration has probably experienced the most rapid development in the recent years due to the greater availability of natural gas, rapid progress in the technology, significant reduction in installation costs, and better environmental performance. Furthermore, the gestation period for developing a project is shorter and the equipment can be delivered in a modular manner. Gas turbine has a short start-up time and provides the flexibility of intermittent operation. Though it has a low heat to power conversion efficiency, more heat can be recovered at higher temperatures. If the heat output is less than that required by the user, it is possible to have supplementary natural gas firing by mixing additional fuel to the oxygen-rich exhaust gas to boost the thermal output more efficiently.
The concept of cogeneration 7 Electricity Generator Fuel Air Flue Gases (~ 500 °C) Gas Turbine Boiler Exhaust Heat (~ 150 °C) Steam Water Figure 1.3 Schematic diagram of gas turbine cogeneration On the other hand, if more power is required at the site, it is possible to adopt a combined cycle that is a combination of gas turbine and steam turbine cogeneration. Steam generated from the exhaust gas of the gas turbine is passed through a backpressure or extractioncondensing steam turbine to generate additional power. The exhaust or the extracted steam from the steam turbine provides the required thermal energy. 1.4.3 Reciprocating engine cogeneration systems Also known as internal combustion (I. C.) engines, these cogeneration systems have high power generation efficiencies in comparison with other prime movers. There are two sources of heat for recovery: exhaust gas at high temperature and engine jacket cooling water system at low temperature (see Figure 1.4). As heat recovery can be quite efficient for smaller systems, these systems are more popular with smaller energy consuming facilities, particularly those having a greater need for electricity than thermal energy and where the quality of heat required is not high, e.g. low pressure steam or hot water. Though diesel has been the most common fuel in the past, the prime movers can also operate with heavy fuel oil or natural gas. In urban areas where natural gas distribution network is in place, gas engines are finding wider application due to the ease of fuel handling and cleaner emissions from the engine exhaust. These machines are ideal for intermittent operation and their performance is not as sensitive to the changes in ambient temperatures as the gas turbines. Though the initial investment on these machines is low, their operating and maintenance costs are high due to high wear and tear. 1.5 Classification of Cogeneration Systems Cogeneration systems are normally classified according to the sequence of energy use and the operating schemes adopted.
Page 1: PART 1: OVERVIEW OF COGENERATION AN
Page 4 and 5: 4 Part I: Overview of cogeneration
Page 12 and 13: State of art review of cogeneration
Page 36 and 37: Policy framework for promoting coge
Page 46 and 47: Cogeneration in Asia today 49 1.1 I
Page 48 and 49: Cogeneration in Asia today 51 4,000
Page 50 and 51: Cogeneration in Asia today 53 1.3 T
Page 52 and 53: Cogeneration in Asia today 55 1.3.3
Page 54 and 55: Cogeneration in Asia today 57 1.4.3
Page 56 and 57:
Cogeneration in Asia today 59 1.5.2
Page 58 and 59:
Cogeneration in Asia today 61 1.7 R
Page 60 and 61:
Cogeneration in Asia today 63 Every
Page 62 and 63:
Cogeneration in Asia today 65 Cogen
Page 64 and 65:
68 Part II: Cogeneration experience
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Cogeneration experiences around the
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90:
PART 3: SUMMARY OF COUNTRY STUDIES
Page 93 and 94:
98 Part3: Summary of country studie
Page 95 and 96:
100 Part3: Summary of country studi
Page 97 and 98:
Sample case study in a pulp and pap
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Summary of country study - Banglade
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Summary of country study - Viet Nam
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177:
show all

part 1: overview of cogeneration and its status in asia - Fire

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?