2 replies to this topic

[wingsofdreams]

hi...
I am working on to select the hot utility to heat up the process streams.....one of process stream need to be heated up from 300 to 370 C (4000kW) and the other from 640 to 658 C (3000kW).....My delta Tmin value for both streams is 10 C.......

We were discussing about which hot utility is less expensive as far as possible for both capital and operating cost is concerned (safety and operability also to be considered).....according to my view If i select a furnace (fuel:NG) than i can accommodate to heat up both the streams at respective temperatures mentioned above....( i am considering both the streams in different coils (tubes) in single furnace....)

some of my colleague also suggested to use thermic fluid at 370 C....ya its also good idea to avoid heating up of process stream into furnace coil (safety )

One of my colleague suggested that we can use the exhaust gas of gas turbine which is at 690 C......and can use gas exhaust to heat up the process streams in heat exchangers......I cant digest this Idea....The questions arise are following.......
1) Is this possible (practically and economically) to get a one fraction of stream from gas turbine exhaust which is upstream of HRSG.........
2) the area of heat exchanger (GT exhaust - process stream)? (I think it will be large)
3)reliability on gas turbine.....(if in case......gas turbine is down.? then...)

I will appreciate all of ur suggestions to select the hot utility at higher temperature.....

Thank you

[S.AHMAD]

1. Depending what type of facilities available on-sites, you should think of heat integration. For example, exhaust gas from furnace can be used to pre-heat the process stream or can pre-heat the combustion air and the turbine exhaust gas can be used to pre-heat process gas.
2. Develop several alternatives and conduct economic viability of each alternative.
3. The bottom line is economic return.
4. Heat recovery from exhaust gas is not new. Method of sizing is well established.

[breizh]

Hi ,

Consider this resource , it should support your query :

http://www1.eere.ene...ment/steam.html

Breizh