dynamic simulation in hysys!!!!!!!!

[marchese85]

hello!
I am doing a dynamic simulation in hysys !!!... I'm having a big problem with a heat exchanger. The following message appears frequently

E-100 Very low efficiency flash failed. Increased efficiencies to 5% Which flash allowed to succeed.

The mass balances are not correct. In input there is 140 kg / h, in output flow rates are negative.

What does it mean ?????
how can I resolve this??

p.s. sorry for my english
thanks in advance

[Fdias]

Because ur heat exchanger is not sized properly .. u are getting the error .. size the H.E. K value for required press drop & flow , also check the pressure spec u have specified downstream ..it should less than the outlet press specified at the H.E. . if the problem still persist try setting the mass flow factor to -0.001

[marchese85]

what you say is correct .... but since the simulation is in the dynamic state, the flow entering in the heat exchanger is variable in the time !!!...if i consider a smaller volume, i find correct values of flow, but then I have to increase the size of H.E. because the flow is greater !!!!!!!

how do I fix this problem???

sorry for my english

thanks in advance