What are the different losses that occur in a steam turbine?
Losses due to leakage :- In Impulse turbine, leakage loss occurs between the shaft, bearings, nozzles and stationary diaphragms. For Reaction turbine, it may occur at the blade tips. This loss is due to the leakage of steam on each stage of the turbine. Total leakage loss is about 1 to 2% of total turbine loss.
What is an example of energy loss?
Some examples of these losses include: Heat energy, potentially as a result of air drag or friction. Light energy is frequently energy seen in combustion, and is a type of wave motion. Sound energy is another type of wave motion caused by the vibration of molecules in the air.
What type of energy is lost in every energy transformation?
heat energy
What are the losses in boiler?
The Boiler Efficiency Calculator takes into account only major energy losses‚ which typically represent 10 to 20 % of fuel input. The major energy losses associated with boilers fall into two categories: stack losses‚ and radiation and convection losses.
What is boiler efficiency?
Definition of Boiler Efficiency is “The percentage of the total absorption heating value of outlet. steam in the total supply heating value.” In other word, it is a rate how the boiler runs efficiently.
What is stack loss?
Stack loss refers to wasted heat, unburned fuel, and excess air that escape up the flue stack (venting system of residential, commercial, industrial plants and governmental buildings and facilities).
What causes stack effect?
Stack effect is air movement caused by thermal differences. Higher-temperature air is less dense than cooler air. As the warmer air rises, it creates a pressure difference, with lower pressure below and higher pressure above. During summer or in warmer climates, the stack effect is reversed.
What is the difference between chimney and stack?
When you think of a chimney, you may picture the brick structure on top of a roof, but that is actually known as the “stack”. The chimney stack is the part that is above the roofline.
How do you stop dry flue loss of gas?
1) Reducing DG in turn reduces the dry flue gas loss, LDG. The quantity of dry gas (DG) can be reduced by reducing the amount of oxygen in the flue gas i.e. by reducing the excess air. Good burners and precise combustion controls are necessary for good results.
What is the difference between dry flue gas loss and wet flue gas loss?
The dry flue gas loss accounts for the heat lost up the stack in the “dry” products of combustion, that is, CO2, O2, N2, CO and SO2. These carry away only sensible heat, whereas the “wet” products, mainly moisture from the combustion of hydrogen, carry away both latent and sensible heat.
What is dry flue gas?
Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. Quite often, the flue gas refers to the combustion exhaust gas produced at power plants.
How do you calculate the volume of a flue of gas?
If the stoichiometric flue gas volume is divided by H(N) (net calorific value or lower heating value) then the flue gas volume is related to the MJ energy input (m3/MJ fuel). 5 S = VGod / H(N) (m3/MJ) Page 17 -17- PGR/R&E 12-7222 This fuel factor, S, is essentially invariant for a given fuel type.
What is the composition of flue gas?
Flue gases are a mixture of combustion products including water vapor, carbon dioxide, particulates, heavy metals, and acidic gases generated from direct (incineration) or indirect (gasification and pyrolysis) oxidation of RDF or intermediate syngas.
What is the density of flue gas?
Pressure drop calculator, download version preview
| Temperature [OC] | cp [kJ/kgK] | ρ [kg/m3] |
|---|---|---|
| 0.0 | 1.042 | 1.295 |
| 100.0 | 1.068 | 0.95 |
| 200.0 | 1.097 | 0.748 |
| 300.0 | 1.122 | 0.617 |
How do you calculate excess air in a boiler?
When the air/fuel ratio is optimized, the resulting energy savings usually ranges from 5% to >25%. For example, if the oxygen dry reading in flue gas is 2.5%, then the excess-air calculation would be: 0.895 x 0.025 / (0.21-0.025) = 12.1% excess air. Too much excess air leads to lower flame temperature.
What do you mean by stoichiometric air/fuel ratio?
The stoichiometric mixture for a gasoline engine is the ideal ratio of air to fuel that burns all fuel with no excess air. For gasoline fuel, the stoichiometric air–fuel mixture is about 14.7:1 i.e. for every one gram of fuel, 14.7 grams of air are required.
What is excess air in boiler?
There is a theoretical amount of fresh air that when mixed with a fixed amount of fuel, and burnt will result in perfect combustion. In this situation all of the fuel will have been properly burnt and all of the oxygen in the air will have been consumed.
How do I reduce the air in my boiler?
To provide optimum efficiency, operators should clean and adjust burners as required. The most efficient burner mixes fuel and air to minimize excess air for the specific firing rate, ideally throughout the turndown ratio of the burner. Excess air tends to increase at lower turndown ratios.
What is air fuel ratio for boiler?
For natural gas-fired burners, the stoichiometric air required is 9.4-11 ft.3 / 1.0 ft. of natural gas or approximately an air-to-gas ratio of approximately 10:1. In this case, there is an excess oxygen level of 2%. In the combustion zone, it is challenging to measure excess air.
What is a rich AFR?
Lean or Rich Mixtures When an air/fuel mixture has too much fuel, it is rich. An AFR higher than stoich = lean. An AFR lower than stoich = rich. A lambda value higher than 1 = lean. A Lambda value lower than 1 = rich.
What air fuel ratio is too rich?
When the air-fuel ratio is lower than the stoichiometric ratio, the air-fuel mixture is called rich. For example, for a gasoline engine, an AFR of 16.5:1 is lean and 13.7:1 is rich….Air-fuel ratio, lambda and engine performance.
| Fuel | Chemical formula | AFR |
|---|---|---|
| Methane | CH4 | 17.19:1 |
| Hydrogen | H2 | 34.3:1 |
Which is better lean or rich mixture?
“Lean” means a lower fuel-to-air ratio; that is, less fuel in the mix; compared to something context-dependent. “Rich” means a higher fuel-to-air ratio; that is, more fuel in the mix; compared to something context-dependent.
Is backfiring lean or rich?
Lean Air/Fuel Mixture Not only can a rich air/fuel ratio cause a backfire, a mixture that doesn’t have enough gasoline can cause a backfire, too. When a lean mixture combusts, it burns more slowly, meaning there will still be some air and fuel that isn’t used up when the exhaust valves open — leading to a backfire.
How do I know if I am running lean or rich?
Signs Of Your Engine Running Lean
- 1: Bad Performance. Your car will have less power than it had before.
- 2: Car Won’t Start. Your may have trouble starting your car, or your engine may not turn over.
- 3: Spark Plugs Are Clean Or White. A common symptom of your car running lean is that your spark plugs are clean or turn white.