Everything has its pros and cons side, air compressor, too, it has the advantage to meet the needs of production, but the drawback has restricted the development of production, new air compressor can not be a large range of jobs is the best example. So how to solve it? We made the following recommendations: to improve the quality of crude ammonia a) improve the effect of sour water stripper stripper is a former stripper column Process transformation from hydrogen sulfide, sidecut export, under the column diameter consistent, opening rate They are also the same. However, since the lateral line take away 50% to 60% of the stripping steam, hydrogen sulfide stripping section vapor dropped load, power factor reduction valve hole, drop tray efficiency, stripping effect is not good, a lot of hydrogen sulfide gas was brought to the lateral line system, the crude ammonia hydrogen sulfide content. To this end, according to the calculation results of the check of hydrogen sulfide stripping section of the tray by a float valve 64 to block 38, so that the tray opening rate from 9.74% down to 5.78%, the valve hole power factor from 4.4 up to 9.5, greatly improve the hydrogen sulfide stripping section stripping effect, improves the lateral line gas a / S molecular ratio, the crude ammonia segregation after the ammonia content by a 97% rise to 99%, crude ammonia sulfide the hydrogen content by the 8000 × 10-6 (8000ppm) down to 5000 × 10-6 (5000ppm), provides for the further refining of crude high purity ammonia, ammonia gas refined quality greatly improved.
Improved stripper stripper temperature control system temperature, especially in the stripper, the upper temperature is stable is an important parameter affect the smooth operation, affecting the quality of ammonia. The original design is an overhead temperature and the cold feed amount cascade control to achieve tower, the upper temperature stability. Since the top temperature interference factors, lagging severely, can not operate. Actual production experience with both manual control of the feed amount of cold to complete the tower, the upper part of the temperature control, which resulted in the upper temperature fluctuations over a wide range, so that the operating fluctuations, unstable quality of ammonia. Instead of the more sensitive to changes in the feed amount of cold filler segment and the cold temperature cascade feed rate adjusted so stripper, an upper stable temperature control, stable operation, ammonia quality more stable.
Revamping guarantee refined quality, use high-speed pump ensure refining effect, ammonia liquid circulation pump is to ensure that one of the important equipment concentrated ammonia scrubbing ammonia refining effect, but because the production process of concentrated aqueous ammonia is saturated or supersaturated state, the original use gear pumps suited to working conditions, easily evacuated difficult to adjust after the pump and evacuated again on the amount of ammonia is often used without purification to enter the ammonia compressor, resulting in refining effect can not be guaranteed. For circulating fluid characteristics, the selection of good corrosion resistance, suitable process conditions GSBⅠ-speed pump. High-speed pump with open radial straight blade, blade before the installation of the axial flow inducer effective solution to ammonia liquid circulating pump evacuated the problem to ensure that the refining effect of making refined ammonia gas hydrogen sulfide content is controlled 40 × 10-6 (40ppm) or less.
After the change of ammonia purifier after crystallization tank ammonia purifier originally concentrated ammonia ammonia was bubbled through the control NH3 / H2S molecular ratio of greater than 30 to further remove hydrogen sulfide. But in practice, difficult to control, the application effect is not good. According to freeze crystallization process will be changed after the ammonia purifier crystallization tank, the tank added ammonia, ammonia gas was bubbled through liquid ammonia, hydrogen sulphide is formed ammonium hydrosulfide or ammonium sulfide precipitation of crystals to remove hydrogen sulfide. The method is easy to control, easy to control hydrogen sulfide content can be less than 10 × 10-6 (10ppm), and a lower operating temperature (-10 ~ 0 ℃), the ammonia compressor suction temperature controlled at -5 to 5 ℃.