1、 Overview

The ammonia distillation tower is subordinate to the desorption tower and is an operating equipment that evaporates and releases ammonia dissolved in circulating water through the heat transfer of a heat carrier.

The working principle is to use a general heat carrier steam as the heating agent, so that the equilibrium vapor pressure of ammonia on the circulating water surface is greater than the partial pressure of ammonia in the heat carrier. The vapor-liquid two phases are in countercurrent contact for mass and heat transfer, gradually releasing ammonia from the circulating water. A mixture of ammonia steam and water steam is obtained at the top of the tower, and relatively pure circulating water is obtained at the bottom of the tower.

The heating method for the tower kettle can be direct steam or indirect steam (reboiler). The liquid phase condensed by the top ammonia condenser is directly introduced into the tower for reflux, and the rich ammonia water evaporated from ammonia is converted into ammonia wastewater and flows out from the bottom of the tower.

2、 Structural features and classification

Ammonia distillation towers are divided into plate towers and packed towers according to their internal structure. A plate tower consists of a tower body and internal components (trays). Commonly used plate trays include sieve tray and bubble cover tray (Figure 1); A packed tower consists of a tower body, a packing layer, and a liquid distribution device.

A packed tower is a mass transfer equipment that uses the packing inside the tower as the contact component between gas and liquid phases. The packed tower belongs to continuous contact gas-liquid mass transfer equipment, and the two-phase composition changes continuously along the tower height. Under normal operating conditions, the gas phase is the continuous phase and the liquid phase is the dispersed phase.

The ammonia distillation towers produced by our company are mostly plate towers with circular bubble caps, vertical bubble caps, and other internal components. They mainly consist of skirts, tower bodies, tower internals, tower kettles, hanging columns, and connecting pipes. The top connecting pipe flange is usually connected to the flange of the ammonia separator. Generally, 15-30 layers of trays are installed inside the tower, and the tower internals and outer shell are made of stainless steel material, divided into 2-3 sections and welded together on site.

The efficiency of the ammonia distillation tower directly affects the concentration, yield, and steam consumption of the ammonia vapor at the top of the tower. Therefore, increasing the dispersion of the liquid phase to shorten the ammonia molecule transfer path, increase and rapidly update the phase interface is a way to improve the transfer efficiencyThe fundamental purpose of quality and speed.

Fault analysis and troubleshooting:

The possible faults that may occur during trial production and production process, the cause analysis and handling methods are as follows, for reference only: