4 replies to this topic

[apex]

In my MDEA sweetening unit the flash gas generation is 6-7 times more than what I get from simulations of the unit (hysys & pretreat). We recently installed a new unit & in this unit this flash gas generation was high initially but subsequently it has come down drastically & is around 1.5-2 times of the simulated value. I had a talk with a consulting firm & they said that for design purpose they used to multiply the simulation value by a factor of 5. Can anyone throw some light on the solubility of light hydrocarbons in generic MDEA & amount of flash gas generation in MDEA sweetening units.

 

natural gas composition & FLOW:                              OUTLET GAS :  H2S< 4 PPMV

 6.3 MMSCMD     TEMP- 35 C                                    CO2 -- MAXIMUM SLIPPAGE

 

C1--- 80 MOL%                                                  MDEA ENTERING ON 9TH TRAY HENCE 5 TRAY IN

C2------7 MOL%                                                   OPERATION.

C3---- 4.3 MOL%                                                 CONTACTOR----- VALVE TRAY COL (14 TRAY)

 

IC4---- 0.8 MOL%                                                 REGERATOR -----VALVE TRAY COL (21 TRAY)

NC4---- 0.8 MOL%VALVE

IC5----  0.4 MOL%                                              CONTACTOR PRESSURE- 60 KG/CM2G 

NC5---- 0.3 MOL%                                              REGERATOR PRESSURE-1.1 KG/CM2    TEMP TOP - 105 C

C6+ ---- 0.2 MOL%                                                                                                                   TEMP BOT - 129 C

CO2 --- 6.2 MOL%

H2S ---- 200 PPM                                              FLASH DRUM PRESSURE - 8 KG/CM2 G

[gegio1960]

where is your flash? (it should be upstream of the absorber)

real flowrate is either 6-7 or 1.5-2 times more than the simulated figures?

which is the destination of the flashed gas?

which is the destination of the sour (stripped) gas?

[apex]

Flash is downstream of absorber & flashed gas is used as fuel gas . the sweetened gas is sent to dehydration unit for water removal.

[apex]

we have 9 units .out of which 7 are in operation. in 6 units the flash gas generation is very high while in the recently installed unit the flash gas generation is near to the simulation value.

[RockDock]

can you post the output reports for Hysys, ProTreat and the operating data?

 

Do Hysys and ProTreat agree with one another? Or do they have different predictions?

 

I think there may be a good explanation, but I will need to have a closer look.