This blog gives knowledge about power plant engineering. Most of the posts are in the Question & answers form. Mainly mechanical & electrical engineering concepts are discussed in this blog.
why PA fan discharge less than ID fan discharge?
Get link
Facebook
X
Pinterest
Email
Other Apps
primary air density (cold air) more than flue gas (hot air)
1. Mass flow of primary air fan is less than mass flow of ID fan.
2.Temperature of air at Primary fan is less than temperature of flue gas ID fan. So density at primary fan is also higher than flue gas density at ID fan
Depending are two types of boiler depending on pressure:- Positive pressure :- When the pressure in combustion area of the boiler is more than atmospheric pressure, normally forced draft boilers, HRSG are positive pressure. Negative pressure :-When the pressure in combustion area of the boiler is less than atmospheric pressure. This is achieved in balanced draft boilers by using Forced draft fans to force air into boiler (pressuring it)and Induced draft fans to remove air from the boilers to create negative pressure. In general negative pressure boilers are preferred as any flames or exhaust from boiler don't have a tendency to spread outside as the pressure inside is lower. The air ingresses inside incase of small leaks between boiler tube fins( large boiler are not perfectly sealed and have small gaps between fins) and contains the flames in the boiler. It also reduces the risk of explosions in boilers w.r.t. positive pressure boilers.
Deaerator at height not only provides Available suction head at boiler feed pump at higher side than required NPSH but also makes recirculation valve discharge to remain in liquid state and not the gaseous state. because feed water temperature to the BFP (and also the temperature after the throttling in ARC valve) is lower than the saturation temperature of the return line of re-circulation to deaerator.
here's something you must ALWAYS remember Complete Combustion always produces the products of Carbion dioxide and Water. INComplete Combustion tends to produce the products of Carbon Monoxide and water... Carbon monoxide is produced from the lack of oxygen in the atmosphere during combustion, hence smaller carbon compounds are made... Ok...you HAVEN'T done the reaction yet, as seen in your question, so you CAN'T tell whether it's complete or not... go to the reaction and balance it out if there are CO2, then it was COMPLETE, and ... if there was CO, then it was INCOMPLETE Complete combustion: CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l) Incomplete combustion: CH4(g) + 1.5 O2(g) → CO(g) + 2 H2O(l) Incomplete combustion: CH4(g) + 1 O2(g) → C(s) + 2 H2O(l) Complete combustions needs the most oxygen. Insufficient oxygen produces incomplete combustion.
The overall coal plant efficiency ranges from 35 % to 48 %. The value varies with the technology, material, parameters (Temp., Pressure) used. At condenser comes the big loophole in plant efficiency. The steam is condensed for reuse. During this process the latent heat of condensation is lost to the cooling water. This is the major loss and is almost 40 % of the energy input.
The function of the Deaerator is to remove dissolved non-condensable gases and to heat boiler feed water. It consists of a pressure vessel in which water and steam are mixed in a controlled manner. When this occurs, water temperature rises, and all non-condensable dissolved gases are liberated and removed and the effluent water may be considered corrosion free from an oxygen or carbon dioxide stand point. Free air or other non-condensable gases should be vented prior permitting the fluid to enter the Deaerator. Deaerator protects the feed pumps, piping, boiler and any other piece of equipment that is in the boiler feed and return cycle from the effects of corrosive gases i.e. oxygen and carbon dioxide, to a level where they are no longer a corrosion fa...
Rating of transformer: Transformers are generally specified with Apparent power rating rather than active power rating due to following reasons: Reason (1) : Rating of a transformer depends upon temperature rise which depends upon the losses taking place in the Transformer. The temperature can be maintained within permissible limits by using proper cooling system. M ore the effectiveness of cooling system more will be the rating of transformer. For a given cooling system rating of any electrical machine is indirectly determined by the losses present in the machine In a transformer Constant losses depends on the voltage rating Variable Losses depend upon current rating Total losses depends upon v and I ratings ∴ Transformer rating is in terms of v*I which is called as Apparent power rating Reason (2) : During manufacture stage of the transformer, the manufacturer...
1. Mass flow of primary air fan is less than mass flow of ID fan.
ReplyDelete2.Temperature of air at Primary fan is less than temperature of flue gas ID fan. So density at primary fan is also higher than flue gas density at ID fan
This information is really awesome thanks for sharing most valuable information.
ReplyDeletePlant Engineering Services
3D Scanning Reverse Engineering