High pressure strippers for use in urea plants

A system for production of urea comprising:

• a carbamate condenser;
• a urea reactor;
• and
• a shell-and-tube stripper for stripping a urea/carbamate mixture, the stripper comprising a top end in fluid connection with a bottom end through a plurality of tubes disposed within a shell;
• the tope end comprising an inlet for a urea/carbamate mixture and an outlet for a gas mixture comprising a stripping gas and one or more stripped compounds;
• the bottom end comprising an outlet for a urea/carbamate stream concentrated in urea;
• the shell-and-tube stripper further comprising a heating fluid inlet and a heating fluid outlet in fluid connection with a shell-side space disposed between the plurality of tubes and the shell, and a steam belt inlet;
• the shell-and-tube stripper having a longitudinal direction and lateral cross sections, the longitudinal direction being parallel to the tube and the lateral cross sections being perpendicular to the longitudinal direction;
• wherein a plurality of baffles are arranged in the shell-side space, the baffles defining a multi-pass crossflow in the shell-side space, wherein the baffles are parallel with the lateral cross sections within a margin of error of less than 1°;
• and wherein the stripper further comprises a plurality of deflectors positioned in a flow path, wherein the deflectors are at oblique or right angles with respect to the baffles.

A method for stripping a urea/carbamate mixture, the method comprising steps of:

• providing a shell-and-tube stripper for stripping a urea/carbamate mixture, the stripper comprising a top end in fluid connection with a bottom end through a plurality of tubes disposed within a shell;
• the top end comprising an inlet for a urea/carbamate mixture and an outlet for a gas mixture comprising a stripping gas and one or more stripped compounds;
• the bottom end comprising an outlet for a urea/carbamate stream concentrated in urea;
• the shell-and-tube stripper further comprising a heating fluid inlet and a heating fluid outlet in fluid connection with a shell-side space disposed between the plurality of tube and the shell, and a steam belt distributor and an inlet deflector for homogenizing a flow of steam near the healing fluid inlet;
• the shell-and-tube stripper having a longitudinal direction and lateral cross sections, the longitudinal direction being parallel to the tubes and the lateral cross sections being perpendicular to the longitudinal direction;
• wherein a plurality of baffles are arranged in the shell-side space, the baffles defining a multi-pass crossflow in the shell-side space, wherein the baffles are parallel with the lateral cross sections within a margin of error of less than 1°;
• and wherein the stripper further comprises a plurality of deflectors positioned in a flow path, wherein the deflectors are at oblique or right angles with respect to the baffles;
• providing the urea/carbamate mixture to the inlet for the urea/carbamate mixture;
• providing a heating fluid to the shell-side space by means of the heating fluid inlet;
• contacting the urea/carbamate mixture and the stripping gas in a tube-side space disposed within the tubes, and heating the urea/carbamate mixture by means of the heating fluid, thereby obtaining a urea/carbamate stream concentrated in urea;
• extracting the urea/carbamate stream concentrated in urea at the outlet for the urea/carbamate stream concentrated in urea;
• extracting a gas mixture comprising one or more stripped compounds at the outlet for the gas mixture, the one or more stripped compounds comprising NH3, CO2, and water;
• and
• extracting the heating fluid at the heating fluid outlet.