Distillation of ammonia water to produce liquid ammonia

When there is excess recycled ammonia water available, it could be considered. I’d like to know as well – what is the cost?

1. Ammonolysis tower process: The concentrated ammonia solution with an ammonia content of 130–140 tt, sourced from the pure ammonia tower’s circulation pump, is preheated to over 140°C in two series-connected preheaters A/B. It then enters the stripping section of the ammonolysis tower, where it comes into countercurrent contact with the hot gas stream rising from the bottom of the tower, thereby enabling the removal of ammonia gas from the ammonia solution. The ammonia gas stream, containing a certain amount of water vapor, rises and comes into countercurrent contact with the reflux ammonia coming from the upper distillation section; once the desired ammonia concentration is achieved, it is drawn out from the top of the tower and sent to an ammonia condenser for condensation. Part of the condensed ammonia is exported as a finished product, while another part returns to the system as reflux ammonia. A portion of the liquid in the bottom of the tower enters the reboiler, is heated with medium-pressure steam, and then returned to the ammonolysis tower ； A portion of the feed is sent to the shell side of preheaters B/A, where it exchanges heat in counterflow with the ammonia water flowing inside the tubes, thereby preheating the ammonia water ； At the same time, the reactor liquid itself is cooled. The kettle liquid coming out of the preheater enters the water cooler, where it is further cooled to room temperature before being sent to the dilute ammonia tank to be used cyclically as the absorption liquid in the pure ammonia tower. The designed operating pressure of the amination tower is 1.6 MPa; however, since no reflux ammonia is being added at present, the distillation section fails to function. Due to reasons such as the vapor at the top of the tower not being sent to the horizontal cooler, a pressure reduction operation is now being carried out, with the actual operating pressure at 0.4–0.5 MPa. In practice, in order to reduce steam consumption, the ammonia concentration in the reactor broth is kept high, generally above 20 tt; therefore, this reactor broth cannot be discharged to avoid environmental pollution. 2. Steam system: The medium-pressure steam used in the hydrolysis tower comes from the medium-pressure steam main in the boiler room, with a pressure of 2.5 MPa and a temperature of 430°C℃ ； The waste steam is returned to the low-pressure steam main at a pressure of 1.0 MPa. 3. Demineralized water: The demineralized water used in the ammonia removal tower is supplied from the high-pressure demineralized water pipeline network of the demineralization plant; its pressure is 3.0 MPa and temperature is at room level ； During operation, desalinated water is also supplied from this pipeline network to devices such as the net ammonia tower, dilute ammonia tank, and ammonolysis tower. 4. Cooling water system: This position is equipped with two water coolers: one for cooling the circulating absorption liquid in the pure ammonia tower, and the other for cooling the residual liquid in the ammonolysis tower. All cooling water comes from either the old desulfurization cooling circulation system or the carbonization cooling circulation system; after cooling the corresponding fluids, it returns to either of these circulation systems. Ammonia and ammonia water process: When the product recovered from the ammonolysis unit is liquid ammonia, the gaseous ammonia extracted from the top of the ammonolysis tower is first sent to the horizontal ammonia condenser in the freezing section; after being condensed into liquid ammonia, it enters a 100 m3 liquid ammonia storage tank ； The reflux ammonia used in the ammonolysis tower comes from a 100 m3 liquid ammonia storage tank. When the product recovered from ammonolysis is gaseous ammonia containing water vapor, it is sent directly to the carbonation absorption system for further processing into concentrated ammonia solution to produce ammonium carbonate. The ammonia water with a concentration of 130–140 tt produced by the net ammonia tower is sent not only to the ammonolysis tower but also to other units that require ammonia water, such as those for carbonization, desulfurization, and desalination.

What are the operating temperature and pressure of the ammonia purification tower? Must the deionized water used in this tower have a pressure of 3.0 Mpa?； What is the ammonia consumption per ton in the ammonia vaporization tower?