Fully circulating aqueous solution with high-pressure coil

The transformation of the high-pressure column is actually carried out by referring to the carbon dioxide and ammonia stripping processes. The high-pressure column at Shandong Hualu Hengsheng has been in operation for many years, and we have completed the transformation here as well. It has been running for almost a year, and overall the performance is good. The conversion rate can reach 72%. The inputs and costs haven’t been calculated yet, and the operation process is pretty much the same; indeed, ammonia consumption has decreased significantly

The last edit to this post was made by 1025199692 on 2009-10-28 at 18:11. The \"high-pressure section\" mainly includes equipment such as the urea synthesis tower, stripping tower, high-pressure ammonium methoxide condenser, and the second synthesis tower

This post was last edited by lxq700918 on 2009-12-1 20:28. Where was this urea production technology developed? Could you provide a brief overview of the process? Is the ammonia/carbon ratio still 4.0–4.2? The investment required is substantial; the synthesis tower can be reused, but the stripping tower and high-pressure ammonium methoxide condenser are not cheap, along with the high-pressure pipelines as well.

A full circulation of the aqueous solution with a high-pressure coil should not increase the conversion rate. It is mainly to reduce power consumption and steam consumption. As for ammonia consumption, it doesn’t have much to do with this.

After the modification, the H2O/CO2 molecular ratio in the synthesis tower decreases, the operating pressure increases, the operating temperature is around 190°C, and the conversion rate of CO2 improves.

The high-pressure coil is mainly used to increase the conversion rate, which naturally leads to a reduction in ammonia consumption. Of course, reducing power consumption and steam consumption are also certainly goals as you mentioned

The last edit to this post was made by 1025199692 on 2009-10-28 at 18:14. It’s not a new technology – it has already been implemented in many aqueous solution manufacturers. The investment required is quite substantial; however, it is said that by using a stripping tower, a high-pressure ammonium methoxide condenser, and a second urea synthesis tower, the return on investment is quite good, with an estimated recovery period of 2.5 years

The operating pressure should decrease, right? From 25MPa to 17MPa.

This post was last edited by Xieshui on 2009-10-26 at 19:01. The conversion rate doesn’t seem to increase much; the main benefit is energy savings. It’s just a guess (superficial, as I’ve never seen this process before): by adding another stripping column, the pre-separator/first column can be eliminated, leaving only two stages. With the addition of a high-pressure ammonium methoxide condenser, the steam generated in-house can be used for heating in the second stage and the first distillation stage, so the N/C ratio should decrease. Otherwise, the composition of the feed material for stripping will be incorrect, and it won’t be possible to maintain thermal balance in the urea synthesis tower. What about the gases emitted from the synthesis tower? Would a high-pressure scrubber need to be added? Assuming all of the above is in place, it would be a CO2 stripping process (with materials flowing under gravity, and the main structure being several dozen meters tall). All process parameters would need to be adjusted, such as N/C ratio, temperature, pressure, H/C ratio, oxygen content, as well as the requirement for 2.5 MPA steam. Is that correct? “Full circulation of the aqueous solution along with high-pressure stages.”

The first synthesis tower in the high-pressure train, the ammonium methane condenser, the stripping tower, the steam drum, and the steam saturator are the main new equipment; the original synthesis tower, which is the second synthesis tower, now operates at a pressure of around 14 MPa. The operating pressure of the new high-pressure loop is around 20 MPa. The material flows from the ammonium methylate condenser to the first synthesis tower and then to the stripping tower; the liquid phase exiting the stripping tower goes to the pre-distillation unit, while the gas phase proceeds to the second synthesis tower where it reacts with methylamine and carbon dioxide. The material exiting the second synthesis tower enters the aqueous solution processing stream.