Leakage issue in the waste heat boiler of a dual-pressure nitric acid plant
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A waste heat boiler for a dual-pressure nitric acid plant, with boiler water as the fluid in the tube side at a pressure of 3.8 MPa; nitrogen oxide gas is present on the shell side at a pressure of 0.35 MPa. When there is an internal leak in the device, does water leak into the nitrogen oxide gas, or does the nitrogen oxide gas leak into the water?
This post was last edited by lxq700918 on 2010-4-23 09:05. Based on an analysis of the operating pressures inside and outside the heat exchange tubes of the waste heat boiler, the pressure inside the tubes is much higher than that outside; it seems that water has leaked into the shell side That is, water leaks into the nitric oxide gas. However, this is purely a theoretical speculation; experts in the field of nitric acid should share their insights on whether this is indeed the case in practical operations.
Water must have seeped into the nitric oxide gas.
Our company has experienced an incident of this kind, where water seeped into the gas, causing the temperature of the gas entering the high-temperature heat exchanger to drop. If the amount of leakage is excessive, it can also lead to an increase in secondary air
The waste heat boiler in dual-pressure nitric acid plants is prone to failures; these are manifested first by a decrease in the concentration of condensed acid, with this amount increasing over time, as well as a drop in the temperature of nitrogen oxides in the oxidation furnace. Sometimes there are changes in the temperature of the furnace walls, at which point it is necessary to shut down the plant for inspection. In severe cases, this can affect the operation of the steam drum and even compromise the safety of the platinum mesh.
Water leaks into the nitric oxide gas, causing the temperature of the entire rear system to drop and the concentration of condensed acid to decrease
Based on the responses from the above-mentioned personnel, it is basically water from the high-pressure side that leaks into the nitrogen oxide in the low-pressure side, and this is a normal phenomenon. But I have found that nitric oxide from the low-pressure side has flowed back into the water on the high-pressure side ； Imagine there is a very small hole in the tube; the water on the high-pressure side will draw the nitrogen oxide from the low-pressure side into the water, just like a ejector, right? Could everyone discuss it?
I have a gentle question: what are the reasons for leaks in the tubes in the overheating section? How many years are pipes generally used for?
Leakage in the superheater tubes is caused by: oxygen corrosion, poor material quality, and overheating
The waste tank we are using is also leaking; water is leaking into the nitric oxide gas. What is the cause of the leakage in the waste tank? How to handle it?
Reasons for waste heat boiler leakage: Poor quality of boiler water, high salt content, which leads to scaling and uneven heating of the coils, resulting in leakage； Oxygen corrosion caused by inadequate deoxygenation of boiler water ； Improper heating and pressure increase during boiler startup and shutdown ； Material issue of its own