Two-step preparation technology of amino sulfonic acid

Abstract

A two-step process for preparing aminosulfonic acid from SO3 gas generated by sulfuric acid plant features that the fire step features high reaction temp and limited addition of SO3 and the second step features low reaction temp and addition of sufficient SO3, resulting in high safety and low cost.

Description

technical field

[0001] The invention relates to a preparation process of sulfamic acid, in particular to an improved process for preparing dry sulfamic acid in two steps using urea, sulfuric acid and sulfur trioxide as raw materials. Background technique

[0002] There are many ways to prepare sulfamic acid, such as solvent cooling method, liquid sulfur trioxide excess method, solid solvent method, two-step method, etc.

[0003] The solvent heat dissipation method is to try to dissipate the heat of reaction through solvent vaporization-condensation, so as to control the progress of the reaction. U.S. Patent No. 4,386,060 discloses a method that uses chlorofluorocarbons as solvents to directly produce dry sulfamic acid with a content of 92%, but the product color is yellow, and chlorofluorocarbons will be banned in 2005, so it has been No practical significance.

[0004] The liquid sulfur trioxide excess method is to put the reactant urea and sulfuric acid into a large amou...

Examples

Embodiment 1

[0018] A continuous reaction device consisting of two reactors connected in series, 80 parts per hour of 20% concentration of fuming sulfuric acid, 40 parts of urea, and 25 parts of liquid sulfur trioxide are added to the first reactor, and the stirring and cooling are controlled at 50 ~40°C temperature range; then add 35 parts of liquid sulfur trioxide per hour to the second reactor, stir and cool to control the temperature range of 40~25°C; the complex formed by the reaction overflows continuously from the second reactor To the flaking machine, heated to 70 ~ 90 ° C to immediately produce dry sulfamic acid, and then remove sulfur trioxide through a degassing device, the final product sulfamic acid content is 93.58%, and the relative urea yield is 94.67%.

Embodiment 2

[0020] A continuous reaction device consisting of three reactors connected in series, 161 parts per hour of 31% concentration of fuming sulfuric acid and 40 parts of urea are added to the first reactor, stirred and cooled to control the temperature range of 55 to 45 ° C; Add 35 parts of urea and 50 parts of sulfur trioxide (the sulfur trioxide conversion gas of the sulfuric acid factory, containing 7.9% sulfur trioxide volume ratio) into the second reaction kettle at a rate of 35 parts per hour, stir and cool to control the temperature range of 46 to 40 °C. Finally, add the third reactor at a rate of 50 parts per hour of sulfur trioxide (same as above), and its material temperature is controlled at 40 to 20°C; Dry sulfamic acid is produced immediately at 70-90°C, and sulfur trioxide is removed through a degassing device. The content of sulfamic acid in the final product is 93.00%, and the relative urea yield is 93.56%.

Embodiment 3

[0022] A continuous reaction device consisting of four reactors connected in series, 181 parts per hour of 22% concentration of fuming sulfuric acid and 30 parts of urea are added to the first reactor, stirred and cooled to control the temperature of the feed liquid between 60 and 50 ° C, and then Add the second reactor at the rate of 30 parts of urea per hour, 35 parts of sulfur trioxide (one stage of sulfur trioxide conversion gas in sulfuric acid plant, containing sulfur trioxide volume ratio of 7.9%), and then add 27 parts of urea per hour, 35 parts of sulfur trioxide Sulfur trioxide (same as above) was added to the third reactor, and 40 parts of sulfur trioxide (same as above) was added to the fourth reactor per hour. ~25°C, the reaction materials overflowing from the first, second, third, and fourth reactors enter the second, third, and fourth reactors and flaking machine respectively. The complex flowing to the flaking machine is immediately heated to 70-90°C, and rapid...

technical field

[0001] The invention relates to a preparation process of sulfamic acid, in particular to an improved process for preparing dry sulfamic acid in two steps using urea, sulfuric acid and sulfur trioxide as raw materials. Background technique

[0002] There are many ways to prepare sulfamic acid, such as solvent cooling method, liquid sulfur trioxide excess method, solid solvent method, two-step method, etc.

[0003] The solvent heat dissipation method is to try to dissipate the heat of reaction through solvent vaporization-condensation, so as to control the progress of the reaction. U.S. Patent No. 4,386,060 discloses a method that uses chlorofluorocarbons as solvents to directly produce dry sulfamic acid with a content of 92%, but the product color is yellow, and chlorofluorocarbons will be banned in 2005, so it has been No practical significance.

[0004] The liquid sulfur trioxide excess method is to put the reactant urea and sulfuric acid into a large amou...

Examples

Embodiment 1

[0018] A continuous reaction device consisting of two reactors connected in series, 80 parts per hour of 20% concentration of fuming sulfuric acid, 40 parts of urea, and 25 parts of liquid sulfur trioxide are added to the first reactor, and the stirring and cooling are controlled at 50 ~40°C temperature range; then add 35 parts of liquid sulfur trioxide per hour to the second reactor, stir and cool to control the temperature range of 40~25°C; the complex formed by the reaction overflows continuously from the second reactor To the flaking machine, heated to 70 ~ 90 ° C to immediately produce dry sulfamic acid, and then remove sulfur trioxide through a degassing device, the final product sulfamic acid content is 93.58%, and the relative urea yield is 94.67%.

Embodiment 2

[0020] A continuous reaction device consisting of three reactors connected in series, 161 parts per hour of 31% concentration of fuming sulfuric acid and 40 parts of urea are added to the first reactor, stirred and cooled to control the temperature range of 55 to 45 ° C; Add 35 parts of urea and 50 parts of sulfur trioxide (the sulfur trioxide conversion gas of the sulfuric acid factory, containing 7.9% sulfur trioxide volume ratio) into the second reaction kettle at a rate of 35 parts per hour, stir and cool to control the temperature range of 46 to 40 °C. Finally, add the third reactor at a rate of 50 parts per hour of sulfur trioxide (same as above), and its material temperature is controlled at 40 to 20°C; Dry sulfamic acid is produced immediately at 70-90°C, and sulfur trioxide is removed through a degassing device. The content of sulfamic acid in the final product is 93.00%, and the relative urea yield is 93.56%.

Embodiment 3

[0022] A continuous reaction device consisting of four reactors connected in series, 181 parts per hour of 22% concentration of fuming sulfuric acid and 30 parts of urea are added to the first reactor, stirred and cooled to control the temperature of the feed liquid between 60 and 50 ° C, and then Add the second reactor at the rate of 30 parts of urea per hour, 35 parts of sulfur trioxide (one stage of sulfur trioxide conversion gas in sulfuric acid plant, containing sulfur trioxide volume ratio of 7.9%), and then add 27 parts of urea per hour, 35 parts of sulfur trioxide Sulfur trioxide (same as above) was added to the third reactor, and 40 parts of sulfur trioxide (same as above) was added to the fourth reactor per hour. ~25°C, the reaction materials overflowing from the first, second, third, and fourth reactors enter the second, third, and fourth reactors and flaking machine respectively. The complex flowing to the flaking machine is immediately heated to 70-90°C, and rapid...