Ethylene glycol consumption

[MT47]

Hi Please help me:
I want to estimate ethylene glycol (50%) consumption for indirect fire heater.Design duty of fire heater is 19.2 MMBtu/hr.Is there any one to help me for calculation?
thank you .

 

[TD2K]

What do you mean by consumption? Losses from your system?

 

[MT47]

My mean is Ethylen glycol for start-up and losses during operation.
Thank you

 

[TD2K]

I'm still not clear where your losses are coming from. Can you explain your system in more detail.

 

[MT47]

Salty crude should be heated before desalting unit up to 69'C .Indirect fired heater is used as crude heater.The bath of the heater is water- ehylene glycol(50%).
I need to estimate the value of ethyene glycol as bath in start-up and losses during normal operation.
Is there design criteria for calculation of liquid value(Water & glycol)of indirect fired heater.
Thank you

 

[hawkeyes]

If you want some help with this one you'll have to be clearer. Are you using hot Glycol/water in a heat exchanger to heat the crude?

 

[1969grad]

TD2K and Hawkeyes:

I think that MT47 is referring to a water bath heater such as made by NATCO and others. This type of heater has a fire tube and pipe heating coil both immersed in a tank of EG-water mixture at atm pressure. Heat transfer is from the fire tube to the EG-water and then from the EG-water to the heating coil - hence the term indirect. The water bath is static - no external circulation.

My suggestion to MT47 is to call the manufacturer for their advice. However, if I were ordering a quantity of EG for fill plus leakage, etc. the later quantity will be small. Just order an extra barrel of EG-water mix and move on.

 

[TD2K]

I think you are right Grad. MT47, if you are talking about losses, those should be minor if you properly precommission the system and ensure all connections are tight. If you are talking about the startup volumes, that should be listed in the operating manual. Be sure you remember the glycol/water mixture is going to expand as it's heated to operating temperature and you need to allow sufficient room in the vessel for it but this should be discussed in the operating/startup manual.

If you need more help we'll need more details just what you are trying to answer.

 

[MT47]

Thank you from everyone to replay me.
TDK2 has true idea about the indirected fire heater system.
I want to determine the volume of ethylen glycol as one of the chemical for the proposal step ,there for in need to estimation of chemical consumption ,but i couldn't find vendor or a good vendor catalog to guide me.If you help me i will be thankful.

 

[TD2K]

For "volumen of ethylene glycol" are you talking about the amount to fill the system initially?

 

[1969grad]

I think the problem is that MT47 lacks the ability to communicate what he is trying to do. Until he is able to define the problem adequately then we cannot help him. Perhaps he should get some additional guidance from a senior engineer at his company or the person sizing the heater.

Seems to me that he is going to have to make a preliminary heater selection from the a vendor's web site, natco for example, then he knows how big the heater shell is. These types of heaters are very common so there should be lots of catalog data available if you spend the time to look.

Like I said before, the volume of operating losses (leakage for example) is very, very small compared to the shell fill volume. So make a preliminary heater selection, calculate or look up the amount of fill and then add a contengency.

Glycol is sold in 55 gallon barrels. So whatever fill volume you determine then you have to round up to a number of barrels. To account for operating losses you just add a barrel.

There is no correlation between heat duty and the volume of operating losses. Furthermore, the quantity of operating losses is dependent or how good a job the installation contractor does.

Bottom line is that the quantity of operating losses is not an exact calculation.