why IBD Vent is kept at higher elevation than CBD ?

Answer Posted / shahnawaz ahmad

Intermittent blowdown better known as bottom blowdown or mud drum blowdown is done to remove undissolved solids from the mud drum of a boiler or from the bottom of the shell of a fire tube boiler. Some boilers operated at high pressure with super clean water dont need this very often. The pipe from the mud drum goes to a tank the purpose of which is to reduce the pressure to atmospheric and to reject heat so that the water/mud mixture is cool enough not to damage the sewer lines or whatever fixtures it flows to. This tank is the intermittent blowdown tank or the atmospheric blowdown tank since it is vented to atmosphere.

The continuous blowdown tank is a flash tank used to collect heat from the water that is continuously drawn from the steam drum in order to control the dissolved solids. As water is boiled off to steam in the steam drum anything that will not evaporate is left behind and this will increase the concentration of dissolved solids in the boiler water. This is bad because the solids will precipitate out and form scale which must be removed chemically and water with high solids concentration will start to foam which will cause level control problems and will also result in material carrying over with the steam resulting in deposits in the superheater tubes and headers. To control this some of the high concentration boiler water is drawn off and replaced with lower concentration feed water.

This flows to a tank at a lower pressure than that in the drum and some of the water flashes to steam, which can be used to heat feedwater or what have you. The liquid left over can be used in a heat exchanger to heat make-up water or it can flow through a standby boiler to keep it warm and to maintain the chemicals in the water or to the circulating water in a cooling tower or to the atmospheric blow down tank.

Is This Answer Correct ?    5 Yes 1 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

How to calculate power press toneage

1565


what is the trip circuit supervision in an electrical meaning?

1447


procedure of how to generate power in solar plant.

1381


How do you consider that you can improve and what assistance do you need to achieve this

1339


LAPT working in alternator / generator

2559






Why superheated are started before I'd and rd fan?

1700


im try to calculating seawater flow required for SW-FGD system. I need a guide, equation or method to do it, can some one help me! Thanks very much

1484


why is the in steam turbine axial displacement of active side thrust pad is positive and non active side thrust pad is negative.

2772


DCS marshaling Cabinet Power supply can be replace during plant running time? Answer Yes it is possible. I am talking about the controller and cards power supply modules. They are always redundant and connected through diode so that if one power supply fails the other can take the charge immediately.so it is possible to replace one of them in running plant if the other one is healthy. MY question is how switching done.

519


how to differentiate between "ALL fuel lost" and "All Fuel Lost" in Boiler MFT condition?

1239


What is difference between secondary Air & Tertiary Air and Their use.?

1483


why do you consider yourself a suitable candidate for this position

6992


what's the moog valve

1060


By any way can we increase the B check hours from 300 to 500

1701


what does mean by kva rating

1000