Hello guys .

I was trying to enable Economic analysis in Aspen hysys v10 but a weird showed up !

the project is Natural Gas plant model / One the Hysys Examples that you can find it in hysys examples .

I previously ran the economics and it worked but after some days when I ran it there was an error : "ERROR> 'HE - 36' ERROR IN STREAM DATA: ICUST-IN

ZERO/NEGATIVE VALUES FOR VAPOR MASS DENSITY NOT ALLOWED

ERROR> 'HE - 36' ERROR IN STREAM DATA: ICUST-EX

ZERO/NEGATIVE VALUES FOR VAPOR MASS DENSITY NOT ALLOWED" in my Heat Exchangers

Nothing Changed from the last successful economics Run and I really don't know why this Error appeared unexpectedly !

I couldn't find any Zero or Negative values and all data is as same as the first time .

Thank you