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69-504: The Rajiv Gandhi Combined Cycle Power Plant or Kayamkulam Thermal Power Plant (also known as Rajiv Gandhi CCPP) is a combined cycle power plant located at shore of Kayamkulam Lake in Choolatheruvu, Muthukulam in Alappuzha district , Kerala , India. The power plant is owned by NTPC Limited . The power plant is fueled by imported and indigenous naphtha . Source of the cooling water

138-577: A gas mask . Diesel exhaust is the exhaust gas produced by a diesel engine , plus any contained particulates . Its composition may vary with the fuel type, rate of consumption or speed of engine operation (e.g., idling or at speed or under load), and whether the engine is in an on-road vehicle, farm vehicle, locomotive, marine vessel, or stationary generator or other application. Diesel exhaust causes lung cancer and other diseases such as asthma , and many premature deaths. Methods exist to reduce nitrogen oxides (NO x ) and particulate matter (PM) in

207-508: A heat recovery steam generator (HRSG) with a live steam temperature between 420 and 580 °C. The condenser of the Rankine cycle is usually cooled by water from a lake, river, sea or cooling towers . This temperature can be as low as 15 °C. Plant size is important in the cost of the plant. The larger plant sizes benefit from economies of scale (lower initial cost per kilowatt) and improved efficiency. For large-scale power generation,

276-510: A tailpipe filter installed, while the United States has mandated it for diesel only. In 2022, British testing specialist Emissions Analytics estimated that the 300 million or so gasoline vehicles in the US over the subsequent decade would emit around 1.6 septillion harmful particles. Carbon dioxide is a greenhouse gas . Motor vehicle CO 2 emissions are part of the anthropogenic contribution to

345-430: A 50.00 MJ/kg (21,500 BTU/lb) LHV: a 11% increase. Efficiency of the turbine is increased when combustion can run hotter, so the working fluid expands more. Therefore, efficiency is limited by whether the first stage of turbine blades can survive higher temperatures. Cooling and materials research are continuing. A common technique, adopted from aircraft, is to pressurise hot-stage turbine blades with coolant. This

414-634: A backup or supplementary power. It is named after American professor D. Y. Cheng who patented the design in 1976. The efficiency of a heat engine, the fraction of input heat energy that can be converted to useful work, is limited by the temperature difference between the heat entering the engine and the exhaust heat leaving the engine. In a thermal power station , water is the working medium. High pressure steam requires strong, bulky components. High temperatures require expensive alloys made from nickel or cobalt , rather than inexpensive steel . These alloys limit practical steam temperatures to 655 °C while

483-415: A business add plant capacity as it is needed. Multiple-pressure reheat steam cycles are applied to combined-cycle systems with gas turbines with exhaust gas temperatures near 600 °C. Single- and multiple-pressure non-reheat steam cycles are applied to combined-cycle systems with gas turbines that have exhaust gas temperatures of 540 °C or less. Selection of the steam cycle for a specific application

552-420: A catalytic converter up to 100,000 ppm (10%) for a richly tuned carburetor engine, such as typically found on small generators and garden equipment. Exhaust gas from an internal combustion engine whose fuel includes nitromethane will contain nitric acid vapour, which is corrosive, and when inhaled causes a muscular reaction making it impossible to breathe. People who are likely to be exposed to it should wear

621-446: A combined heat and power (CHP) plant. In general, combined cycle efficiencies in service are over 50% on a lower heating value and Gross Output basis. Most combined cycle units, especially the larger units, have peak, steady-state efficiencies on the LHV basis of 55 to 59%. A limitation of combined cycles is that efficiency is reduced when not running at continuous output. During start up,

690-520: A marine CCGT safer by permitting a ship to operate with equipment failures. A flexible stationary plant can make more money. Duct burning raises the flue temperature, which increases the quantity or temperature of the steam (e.g. to 84 bar, 525 degree Celsius). This improves the efficiency of the steam cycle. Supplementary firing lets the plant respond to fluctuations of electrical load, because duct burners can have very good efficiency with partial loads. It can enable higher steam production to compensate for

759-552: A means of load control or load shifting since ice can be made during periods of low power demand and, potentially in the future the anticipated high availability of other resources such as renewables during certain periods. Combustion technology is a proprietary but very active area of research, because fuels, gasification and carburation all affect fuel efficiency. A typical focus is to combine aerodynamic and chemical computer simulations to find combustor designs that assure complete fuel burn up, yet minimize both pollution and dilution of

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828-422: A more efficient steam cycle. However, a multi-shaft system is about 5% higher in initial cost. The overall plant size and the associated number of gas turbines required can also determine which type of plant is more economical. A collection of single shaft combined cycle power plants can be more costly to operate and maintain, because there are more pieces of equipment. However, it can save interest costs by letting

897-407: A percentage of the lower heating value of the fuel consumed, can be over 60% when operating new, i.e. unaged, and at continuous output which are ideal conditions. As with single cycle thermal units, combined cycle units may also deliver low temperature heat energy for industrial processes, district heating and other uses. This is called cogeneration and such power plants are often referred to as

966-438: A single cycle steam power plant is limited to efficiencies from 35 to 42%. Many new power plants utilize CCGTs. Stationary CCGTs burn natural gas or synthesis gas from coal . Ships burn fuel oil . Multiple stage turbine or steam cycles can also be used, but CCGT plants have advantages for both electricity generation and marine power. The gas turbine cycle can often start very quickly, which gives immediate power. This avoids

1035-434: A single electrical generator on a single shaft. This arrangement is simpler to operate, smaller, with a lower startup cost. Single-shaft arrangements can have less flexibility and reliability than multi-shaft systems. With some expense, there are ways to add operational flexibility: Most often, the operator desires to operate the gas turbine as a peaking plant. In these plants, the steam turbine's shaft can be disconnected with

1104-602: A synchro-self-shifting (SSS) clutch, for start up or for simple cycle operation of the gas turbine. Another less common set of options enable more heat or standalone operation of the steam turbine to increase reliability: Duct burning, perhaps with a fresh air blower in the duct and a clutch on the gas turbine side of the shaft. A multi-shaft system usually has only one steam system for up to three gas turbines. Having only one large steam turbine and heat sink has economies of scale and can have lower cost operations and maintenance. A larger steam turbine can also use higher pressures, for

1173-556: A thermodynamic cycle that operates between the gas-turbine's high firing temperature and the waste heat temperature from the condensers of the steam cycle. This large range means that the Carnot efficiency of the cycle is high. The actual efficiency, while lower than the Carnot efficiency, is still higher than that of either plant on its own. The electric efficiency of a combined cycle power station, if calculated as electric energy produced as

1242-626: A typical set would be a 270 MW primary gas turbine coupled to a 130 MW secondary steam turbine, giving a total output of 400 MW. A typical power station might consist of between 1 and 6 such sets. Gas turbines for large-scale power generation are manufactured by at least four separate groups – General Electric, Siemens, Mitsubishi-Hitachi, and Ansaldo Energia. These groups are also developing, testing and/or marketing gas turbine sizes in excess of 300 MW (for 60 Hz applications) and 400 MW (for 50 Hz applications). Combined cycle units are made up of one or more such gas turbines, each with

1311-474: A waste heat steam generator arranged to supply steam to a single or multiple steam turbines, thus forming a combined cycle block or unit. Combined cycle block sizes offered by three major manufacturers (Alstom, General Electric and Siemens) can range anywhere from 50 MW to well over 1300 MW with costs approaching $ 670/kW. The heat recovery boiler is item 5 in the COGAS figure shown above. Hot gas turbine exhaust enters

1380-430: A water washing procedure. A simpler and less expensive purification system will do the same job for light crude and light distillates. A magnesium additive system may also be needed to reduce the corrosive effects if vanadium is present. Fuels requiring such treatment must have a separate fuel-treatment plant and a system of accurate fuel monitoring to assure reliable, low-maintenance operation of gas turbines. Xcel Energy

1449-508: A wider range of temperatures or heat to electric power. Systems burning low quality fuels such as brown coal or peat might use relatively expensive closed-cycle helium turbines as the topping cycle to avoid even more expensive fuel processing and gasification that would be needed by a conventional gas turbine. A typical single-shaft system has one gas turbine, one steam turbine, one generator and one heat recovery steam generator (HRSG). The gas turbine and steam turbine are both coupled in tandem to

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1518-470: Is Achankovil river at Nalukettumkavala in Pallipad. There is a plan to expand the plant by three units with capacity of 350 MW each. New units would be fueled by re-gasified liquefied natural gas . Combined cycle The principle is that after completing its cycle in the first engine, the working fluid (the exhaust) is still hot enough that a second subsequent heat engine can extract energy from

1587-406: Is a simplified form of combined cycle where the steam turbine is eliminated by injecting steam directly into the combustion turbine. This has been used since the mid 1970s and allows recovery of waste heat with less total complexity, but at the loss of the additional power and redundancy of a true combined cycle system. It has no additional steam turbine or generator, and therefore it cannot be used as

1656-471: Is also bled-off in proprietary ways to improve the aerodynamic efficiencies of the turbine blades. Different vendors have experimented with different coolants. Air is common but steam is increasingly used. Some vendors might now utilize single-crystal turbine blades in the hot section, a technique already common in military aircraft engines. The efficiency of CCGT and GT can also be boosted by pre-cooling combustion air. This increases its density, also increasing

1725-419: Is also some development of modified Rankine cycles. Two promising areas are ammonia/water mixtures, and turbines that utilize supercritical carbon dioxide. Modern CCGT plants also need software that is precisely tuned to every choice of fuel, equipment, temperature, humidity and pressure. When a plant is improved, the software becomes a moving target. CCGT software is also expensive to test, because actual time

1794-537: Is called " combined heat and power " (CHP). In stationary and marine power plants, a widely used combined cycle has a large gas turbine (operating by the Brayton cycle ). The turbine's hot exhaust powers a steam power plant (operating by the Rankine cycle ). This is a combined cycle gas turbine (CCGT) plant. These achieve a best-of-class real (see below) thermal efficiency of around 64% in base-load operation. In contrast,

1863-539: Is colorless, odorless and tasteless, but highly toxic. It combines with hemoglobin to produce carboxyhemoglobin , which blocks the transport of oxygen. At concentrations above 1000ppm it is considered immediately dangerous and is the most immediate health hazard from running engines in a poorly ventilated space. In 2011, 52% of carbon monoxide emissions were created by mobile vehicles in the U.S. Chronic (long-term) exposure to benzene ( C 6 H 6 ) damages bone marrow . It can also cause excessive bleeding and depress

1932-418: Is determined by an economic evaluation that considers a plant's installed cost, fuel cost and quality, duty cycle, and the costs of interest, business risks, and operations and maintenance. By combining both gas and steam cycles, high input temperatures and low output temperatures can be achieved. The efficiency of the cycles add, because they are powered by the same fuel source. So, a combined cycle plant has

2001-707: Is estimated to kill over 5 million people each year. A 2013 study by the Massachusetts Institute of Technology (MIT) indicates that 53,000 early deaths occur per year in the United States alone because of vehicle emissions. According to another study from the same university, traffic fumes alone cause the death of 5,000 people every year just in the United Kingdom. Researchers from the University of California, Los Angeles School of Public Health say preliminary results of their statistical study of children listed in

2070-552: Is estimated to kill over 5 million people each year. Motor vehicle emissions are a common source of air pollution and are a major ingredient in the creation of smog in some large cities. The largest part of most combustion gas is nitrogen (N 2 ), water vapor (H 2 O) (except with pure-carbon fuels), and carbon dioxide (CO 2 ) (except for fuels without carbon); these are not toxic or noxious (although water vapor and carbon dioxide are greenhouse gases that contribute to climate change ). A relatively small part of combustion gas

2139-925: Is going to build two natural gas power plants in the Midwestern United States that can mix 30% hydrogen with the natural gas. Intermountain Power Plant is being retrofitted to a natural gas/hydrogen power plant that can run on 30% hydrogen as well, and is scheduled to run on pure hydrogen by 2045. However others think low-carbon hydrogen should be used for things which are harder to decarbonize , such as making fertilizer , so there may not be enough for electricity generation. Combined-cycle systems can have single-shaft or multi-shaft configurations. Also, there are several configurations of steam systems. The most fuel-efficient power generation cycles use an unfired heat recovery steam generator (HRSG) with modular pre-engineered components. These unfired steam cycles are also

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2208-435: Is important to the functioning of the catalytic converter of an internal combustion engine . It may be measured by an exhaust gas temperature gauge . EGT is also a measure of engine health in gas-turbine engines (see below). During the first two minutes after starting the engine of a car that has not been operated for several hours, the amount of emissions can be very high. This occurs for two main reasons: Comparable with

2277-430: Is limited on the multimillion-dollar prototypes of new CCGT plants. Testing usually simulates unusual fuels and conditions, but validates the simulations with selected data points measured on actual equipment. Exhaust gas Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas , gasoline (petrol) , diesel fuel , fuel oil , biodiesel blends, or coal . According to

2346-479: Is often readily available in rural areas. Gas turbines burn mainly natural gas and light oil. Crude oil, residual, and some distillates contain corrosive components and as such require fuel treatment equipment. In addition, ash deposits from these fuels result in gas turbine deratings of up to 15%. They may still be economically attractive fuels however, particularly in combined-cycle plants. Sodium and potassium are removed from residual, crude and heavy distillates by

2415-482: Is supplied to the low-temperature turbine. A super heater can be provided in the low-pressure circuit. Some part of the feed water from the low-pressure zone is transferred to the high-pressure economizer by a booster pump . This economizer heats up the water to its saturation temperature . This saturated water goes through the high-temperature zone of the boiler and is supplied to the high-pressure turbine . The HRSG can be designed to burn supplementary fuel after

2484-534: Is that emitted from ovens, furnaces and boilers. In steam engine terminology the exhaust is steam that is now so low in pressure that it can no longer do useful work. Mono- nitrogen oxides NO and NO 2 ( NOx ) (whether produced this way or naturally by lightning ) react with ammonia , moisture, and other compounds to form nitric acid vapor and related particles. Small particles can penetrate deeply into sensitive lung tissue and damage it, causing premature death in extreme cases. Inhalation of NO species increases

2553-410: Is the gas turbine power plant cycle is the topping cycle. It depicts the heat and work transfer process taking place in the high temperature region. The cycle a-b-c-d-e-f-a which is the Rankine steam cycle takes place at a lower temperature and is known as the bottoming cycle. Transfer of heat energy from high temperature exhaust gas to water and steam takes place in a waste heat recovery boiler in

2622-404: Is undesirable, noxious, or toxic substances, such as carbon monoxide (CO) from incomplete combustion, hydrocarbons (properly indicated as C x H y , but typically shown simply as "HC" on emissions-test slips) from unburnt fuel, nitrogen oxides (NO x ) from excessive combustion temperatures, and particulate matter (mostly soot ) from incomplete combustion. Exhaust gas temperature (EGT)

2691-440: Is useful to growing plants. When oxides of nitrogen (NOx) and volatile organic compounds (VOCs) react in the presence of sunlight, ground level ozone is formed, a primary ingredient in smog . A 2005 U.S. EPA report gives road vehicles as the second largest source of VOCs in the U.S. at 26% and 19% are from non road equipment which is mostly gasoline and diesel stations. 27% of VOC emissions are from solvents which are used in

2760-596: The European emission standards EURO III as it was applied in October 2000 In 2000, the United States Environmental Protection Agency began to implement more stringent emissions standards for light duty vehicles. The requirements were phased in beginning with 2004 vehicles and all new cars and light trucks were required to meet the updated standards by the end of 2007. In spark-ignition engines

2829-410: The immune system , increasing the chance of infection . Benzene causes leukemia and is associated with other blood cancers and pre-cancers of the blood. The health effects of inhaling airborne particulate matter have been widely studied in humans and animals and include asthma , lung cancer , cardiovascular issues, premature death . Because of the size of the particles, they can penetrate

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2898-408: The super heater , then passes through the evaporator and finally through the economiser section as it flows out from the boiler . Feed water comes in through the economizer and then exits after having attained saturation temperature in the water or steam circuit. Finally it flows through the evaporator and super heater. If the temperature of the gases entering the heat recovery boiler is higher, then

2967-514: The bottoming cycle. During the constant pressure process 4-1 the exhaust gases from the gas turbine reject heat. The feed water, wet and super heated steam absorb some of this heat in the process a-b, b-c and c-d. The steam power plant takes its input heat from the high temperature exhaust gases from a gas turbine power plant. The steam thus generated can be used to drive a steam turbine . The Waste Heat Recovery Boiler (WHRB) has 3 sections: Economiser, evaporator and superheater. The Cheng cycle

3036-498: The capital costs of combined cycle power is relatively low, at around $ 1000/kW, making it one of the cheapest types of generation to install. The thermodynamic cycle of the basic combined cycle consists of two power plant cycles. One is the Joule or Brayton cycle which is a gas turbine cycle and the other is the Rankine cycle which is a steam turbine cycle. The cycle 1-2-3-4-1 which

3105-452: The deepest part of the lungs. A 2011 UK study estimates 90 deaths per year due to passenger vehicle PM. In a 2006 publication, the U.S. Federal Highway Administration (FHWA) state that in 2002 about 1 per-cent of all PM 10 and 2 per-cent of all PM 2.5 emissions came from the exhaust of on-road motor vehicles (mostly from diesel engines ). In Chinese, European, and Indian markets, both diesel and gasoline vehicles are required to have

3174-600: The energy harvested from solar radiation with another fuel to cut fuel costs and environmental impact (See: ISCC section ). Many next generation nuclear power plants can use the higher temperature range of a Brayton top cycle, as well as the increase in thermal efficiency offered by a Rankine bottoming cycle. Where the extension of a gas pipeline is impractical or cannot be economically justified, electricity needs in remote areas can be met with small-scale combined cycle plants using renewable fuels. Instead of natural gas, these gasify and burn agricultural and forestry waste, which

3243-488: The exhaust. In aircraft gas turbine engines, "exhaust gas temperature" (EGT) is a primary measure of engine health. Typically the EGT is compared with a primary engine power indication called "engine pressure ratio" (EPR). For example: at full power EPR there will be a maximum permitted EGT limit. Once an engine reaches a stage in its life where it reaches this EGT limit, the engine will require specific maintenance in order to rectify

3312-400: The expansion ratio of the turbine. This is practised in hot climates and also has the effect of increasing power output. This is achieved by evaporative cooling of water using a moist matrix placed in the turbine's inlet, or by using Ice storage air conditioning . The latter has the advantage of greater improvements due to the lower temperatures available. Furthermore, ice storage can be used as

3381-407: The failure of another unit. Also, coal can be burned in the steam generator as an economical supplementary fuel. Supplementary firing can raise exhaust temperatures from 600 °C (GT exhaust) to 800 or even 1000 °C. Supplemental firing does not raise the efficiency of most combined cycles. For single boilers it can raise the efficiency if fired to 700–750 °C; for multiple boilers however,

3450-470: The flexibility of the plant should be the major attraction. "Maximum supplementary firing" is the condition when the maximum fuel is fired with the oxygen available in the gas turbine exhaust. Combined cycle plants are usually powered by natural gas , although fuel oil , synthesis gas or other fuels can be used. The supplementary fuel may be natural gas, fuel oil, or coal. Biofuels can also be used. Integrated solar combined cycle power stations combine

3519-407: The gas turbine. Supplementary burners are also called duct burners . Duct burning is possible because the turbine exhaust gas (flue gas) still contains some oxygen . Temperature limits at the gas turbine inlet force the turbine to use excess air, above the optimal stoichiometric ratio to burn the fuel. Often in gas turbine designs part of the compressed air flow bypasses the burner in order to cool

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3588-480: The gases resulting from combustion of the fuel and air mix are called exhaust gases. The composition varies from petrol to diesel engines, but is around these levels: The 10% oxygen for "diesel" is likely if the engine was idling, e.g. in a test rig. It is much less if the engine is running under load, although diesel engines always operate with an excess of air over fuel. The CO content for petrol engines varies from ≈15 ppm for well tuned engine with fuel injection and

3657-580: The growth of CO 2 concentrations in the atmosphere which according to the vast majority of the scientific community is causing climate change . Motor vehicles are calculated to generate about 20% of the European Union's man-made CO 2 emissions, with passenger cars contributing about 12%. European emission standards limit the CO 2 emissions of new passenger cars and light vehicles. The European Union average new car CO 2 emissions figure dropped by 5.4% in

3726-578: The heat in the exhaust. Usually the heat passes through a heat exchanger so that the two engines can use different working fluids. By generating power from multiple streams of work, the overall efficiency can be increased by 50–60%. That is, from an overall efficiency of the system of say 34% for a simple cycle, to as much as 64% net for the turbine alone in specified conditions for a combined cycle. Historically successful combined cycles have used mercury vapour turbines , magnetohydrodynamic generators and molten carbonate fuel cells , with steam plants for

3795-607: The hot exhaust gases. Some combustors inject other materials, such air or steam, to reduce pollution by reducing the formation of nitrates and ozone. Another active area of research is the steam generator for the Rankine cycle. Typical plants already use a two-stage steam turbine, reheating the steam between the two stages. When the heat-exchangers' thermal conductivity can be improved, efficiency improves. As in nuclear reactors, tubes might be made thinner (e.g. from stronger or more corrosion-resistant steel). Another approach might use silicon carbide sandwiches, which do not corrode. There

3864-426: The input temperature to the turbine (the firing temperature), is relatively high (900 to 1,400 °C). The output temperature of the flue gas is also high (450 to 650 °C). This is therefore high enough to provide heat for a second cycle which uses steam as the working fluid (a Rankine cycle ). In a combined cycle power plant, the heat of the gas turbine's exhaust is used to generate steam by passing it through

3933-399: The low temperature "bottoming" cycle. Very low temperature bottoming cycles have been too costly due to the very large sizes of equipment needed to handle the large mass flows and small temperature differences. However, in cold climates it is common to sell hot power plant water for hot water and space heating. Vacuum-insulated piping can let this utility reach as far as 90 km. The approach

4002-431: The lower temperature of a steam plant is fixed by the temperature of the cooling water. With these limits, a steam plant has a fixed upper efficiency of 35–42%. An open circuit gas turbine cycle has a compressor , a combustor and a turbine . For gas turbines the amount of metal that must withstand the high temperatures and pressures is small, and lower quantities of expensive materials can be used. In this type of cycle,

4071-427: The lowest in initial cost, and they are often part of a single shaft system that is installed as a unit. Supplementary-fired and multishaft combined-cycle systems are usually selected for specific fuels, applications or situations. For example, cogeneration combined-cycle systems sometimes need more heat, or higher temperatures, and electricity is a lower priority. Multishaft systems with supplementary firing can provide

4140-402: The manufacturer of paints and paint thinners and other uses. Ozone is beneficial in the upper atmosphere, but at ground level ozone irritates the respiratory system , causing coughing, choking, and reduced lung capacity. It also has many negative effects throughout the ecosystem. Carbon monoxide poisoning is the most common type of fatal air poisoning in many countries. Carbon monoxide

4209-568: The need for separate expensive peaker plants , or lets a ship maneuver. Over time the secondary steam cycle will warm up, improving fuel efficiency and providing further power. In November 2013, the Fraunhofer Institute for Solar Energy Systems ISE assessed the levelised cost of energy for newly built power plants in the German electricity sector . They gave costs of between 78 and €100 /MWh for CCGT plants powered by natural gas. In addition

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4278-407: The pollution of exhaust gases using a catalyst. Scrubbers in ships intend to remove the sulfur dioxide (SO 2 ) of marine exhaust gases. The regulations on marine sulfur dioxide emissions are tightening, however only a small number of special areas worldwide have been designated for low sulfur diesel fuel use only. Air pollution from fossil fuel use by industry, power generation, and transportation

4347-430: The problem. The amount the EGT is below the EGT limit is called EGT margin. The EGT margin of an engine will be greatest when the engine is new, or has been overhauled. For most airlines, this information is also monitored remotely by the airline maintenance department by means of ACARS . In jet engines and rocket engines , exhaust from propelling nozzles which in some applications shows shock diamonds . Flue gas

4416-481: The risk of lung cancer and colorectal cancer. and inhalation of such particles may cause or worsen respiratory diseases such as emphysema and bronchitis and heart disease. In a 2005 U.S. EPA study the largest emissions of NO x came from on road motor vehicles, with the second largest contributor being non-road equipment which is mostly gasoline and diesel stations. The resulting nitric acid may be washed into soil, where it becomes nitrate , which

4485-508: The second cycle can take time to start up. Thus efficiency is initially much lower until the second cycle is running, which can take an hour or more. Heat engine efficiency can be based on the fuel Higher Heating Value (HHV), including latent heat of vaporisation that would be recuperated in condensing boilers , or the Lower Heating Value (LHV), excluding it. The HHV of methane is 55.50 MJ/kg (23,860 BTU/lb), compared to

4554-428: The temperature of the exiting gases is also high. In order to remove the maximum amount of heat from the gasses exiting the high temperature cycle, a dual pressure boiler is often employed. It has two water / steam drums. The low-pressure drum is connected to the low-pressure economizer or evaporator. The low-pressure steam is generated in the low temperature zone of the turbine exhaust gasses. The low-pressure steam

4623-413: The turbine blades. The turbine exhaust is already hot, so a regenerative air preheater is not required as in a conventional steam plant. However, a fresh air fan blowing directly into the duct permits a duct-burning steam plant to operate even when the gas turbine cannot. Without supplementary firing, the thermal efficiency of a combined cycle power plant is higher. But more flexible plant operations make

4692-425: The type of engine, it is discharged into the atmosphere through an exhaust pipe , flue gas stack , or propelling nozzle . It often disperses downwind in a pattern called an exhaust plume . It is a major component of motor vehicle emissions (and from stationary internal combustion engines ), which can also include crankcase blow-by and evaporation of unused gasoline. Air pollution from burning fossil fuels

4761-692: The year to the first quarter of 2010, down to 145.6 g/km . Vehicle exhaust contains much water vapour . There has been research into ways that troops in deserts can recover drinkable water from their vehicles' exhaust gases. Emission standards focus on reducing pollutants contained in the exhaust gases from vehicles as well as from industrial flue gas stacks and other air pollution exhaust sources in various large-scale industrial facilities such as petroleum refineries , natural gas processing plants, petrochemical plants and chemical production plants. However, these are often referred to as flue gases . Catalytic converters in cars intend to break down

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