Why does the pressure of the urea synthesis tower need to be increased to 80~~100kg/cm2 when it is initially started?
Thread Content
Why does the pressure of the urea synthesis tower need to be increased to 80~~100kg/cm2 when it is initially started? :o (This is the content of our exam)
The dissociation pressure of pure methane at 150°C is about 70kg/cm2. Since the temperature of the urine tower is already 150°C when feeding, in order to prevent the methane generated after feeding from decomposing, the operating pressure of the urea tower must be greater than the dissociation pressure of methane, so the pressure of the urine tower must be increased to 80~~100kg/cm2 before feeding.
Because the generation of urea is carried out in the liquid phase, in order to keep the synthesized methylammonium in a liquid state after feeding, the pressure of the ammonia boost is slightly higher than the vapor pressure of the melting point of pure methane ammonium, 9.2MPa (gauge pressure).
Three conditions for the generation of carboxamide: First, it must be carried out in the liquid phase, second, the temperature must be above 125 degrees Celsius, and third, the pressure must be above 8.0 MPa, so the pressure must be increased.
one. Urea can be generated by dehydration of methylammonium in the molten state. two. Pure methylammonium is in a molten state at 150 degrees. three. Methyl ammonium can be dehydrated to generate urea without decomposition at 150 degrees 70kg/cm2, that is, the dissociation pressure of methane ammonium at 150 degrees is 70 kilograms. Four. The operating pressure should be 10-20 kg higher than the dissociation pressure at that temperature. Therefore, during initial start-up, the temperature of the synthesis tower should be raised to 150 degrees and the pressure should be raised to above 80kg/cm2. This post was last edited by lxq700918 on 2009-2-10 17:21 ]
Just a little more humble opinion: High-pressure equipment also has requirements for the pressure increase rate. Generally, it takes about 2 hours from feeding to discharging. If the pressure increase rate is 30, it will basically be the designed reaction pressure by the time of discharging, which is good for the equipment and conversion rate. :)
This view is quite unique. Unfortunately, I have run out of ratings today, but I will definitely give you a rating tomorrow, haha! The angle of thinking about the problem is very unusual! ! ! ! This post was last edited by Boating Five Lakes on 2009-3-9 02:37 ]