Sulfuric Acid Alky
Our alky unit refrigeration compressor is limited by low suction pressure. The suction pressure gets down to one psig or less, but contactor temperature is 60°F or more. So, we slow down the compressor (turbine driver), to bring up the suction pressure, but then the contactors get hotter still. Any suggestions would be appreciated.
May I suggest you reduce your depropanizer bottoms temperature by 5°F. This will allow propane to build in your refrigerant recyle and raise compressor suction pressure, but without raising contactor temperature. You need to make moves on the depropanizer bottoms temperature slowly, as it will take several hours for the refrigerant recycle propane content to respond. Note, that if your compressor discharge pressure is at max, this will not work.