A method for replacing ammonia in a liquid ammonia storage tank

Abstract

The invention relates to a replacement method of ammonia gas in a liquid ammonia storage tank. The replacement method comprises that: a, after the liquid ammonia level in a liquid ammonia storage tank decreases to zero, water is filled into the liquid ammonia storage tank while the ammonia gas concentration in the liquid ammonia storage tank is monitored through a detector, the filling of the water into the liquid ammonia storage tank is stopped when the concentration is 0 ppm, all liquid ammonia storage tank connection ports with the outside are closed, soaking is performed for 24 h, and the water in the liquid ammonia storage tank is completely drained; and b, compressed air purging is continuously performed on the internal of the liquid ammonia storage tank from the sewage discharge door on the bottom portion of the liquid ammonia storage tank, ventilation is performed on the internal of the liquid ammonia storage tank through an exhaust fan after the purging is performed on the liquid ammonia storage tank for 4 h, ventilation is stopped when the oxygen content in the tank and detected by an oxygen content detector is 18-22%, and the maintenance personnel can enter the liquid ammonia storage tank to perform maintenance work, wherein the pressure in the liquid ammonia storage tank during the purging is more than or equal to 0.4 Mpa. With the replacement method of the present invention, advantages of cost saving, time saving and construction period shortening are achieved under the premise of assurance of the safe and smooth completion of the maintenance work.

Description

technical field [0001] The invention relates to a method for replacing ammonia in a liquid ammonia storage tank. Background technique [0002] Existing liquid ammonia generally all adopts liquid ammonia storage tank to store, because ammonia is a colorless gas with a pungent smell, it can burn the mucous membranes of the skin, eyes, and respiratory organs, and if people inhale too much, it can cause lung swelling, even die. And when the ammonia air ratio is greater than eight, it is very easy to burn and explode. For ammonia with huge liquid ammonia reserves, safety is the most important indicator. To ensure the safety of storage, it is necessary to regularly overhaul the liquid ammonia storage tank. Existing maintenance After the liquid ammonia in the liquid ammonia storage tank is used up, the residual ammonia gas in the tank is replaced and eliminated, so as to ensure that the maintenance task can be completed smoothly. However, the existing replacement uses nitrogen rep...

AI Technical Summary

Problems solved by technology

[0002] Existing liquid ammonia generally all adopts liquid ammonia storage tank to store, because ammonia is a colorless gas with a pungent smell, it can burn the mucous membranes of the skin, eyes, and respiratory organs, and if people inhale too much, it can cause lung swelling, even die

And when the ammonia air ratio is greater than eight, it is very easy to burn and explode. For ammonia with huge liquid ammonia reserves, safety is the most important indicator. To ensure the safety of storage, it is necessary to regularly overhaul the liquid ammonia storage tank. Existing maintenance After the liquid ammonia in the liquid ammonia storage tank is used up, the residual ammonia gas in the tank is replaced and eliminated, so as to ensure that the maintenance task can be completed smoothly. However, the existing replacement uses nitrogen replacement, so during the replacement process It consumes a lot of nitrogen, which makes the maintenance cost high and takes a lot of time, and the replacement cycle is also long