Liquid level issue in the waste boiler after the exit of the synthesis tower
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I would like to ask fellow sailors: What level should the liquid level in the waste tank be maintained at? What safety hazards could arise if it cannot be done? Should and must the steam pressure of a waste boiler be constant?
The liquid level in the waste boiler must be kept at its upper limit, so that the level is above that of the internal components; this is mainly beneficial for the safe and stable operation of the equipment. Its steam pressure should be equal to the steam pressure of your ammonia synthesis system.
The liquid level in the waste pot should be maintained at 30–60%. If the level is too low, the pot will dry out, which can lead to an explosion. If it is too high, steam will carry water, causing liquid slugging in the piping system. If the outlet temperature of the synthesis tower remains constant, the steam pressure in the waste heat boiler must also be constant.
The level of the waste boiler liquid should be between 35% and 45%; if the level is too high, steam may carry liquid with it, and in the case of steam used for turbine power generation, this can cause scaling on the superheaters and the turbine rotor. An excessively low liquid level can easily cause cracks in the welds at the tube sheet of the upper heat exchange tubes, as well as a dry-boiling condition. The operating pressure of the waste boiler should be maintained at a level that is 2–4 bar higher than the pressure in the steam network. However, it is important to note that changes in operating pressure and temperature can affect the density of the water in the boiler, which in turn leads to a discrepancy between the indicated liquid level and the actual liquid level. In such cases, the indicated level in the boiler does not correspond to the true level; therefore, adjustments must be made to the level indication in order to determine the actual liquid level.
In our facility, the liquid level is kept at 50%, and the pressure must be consistent with that of the steam pipeline network; a too high liquid level can cause surge phenomena and lead to accidents.
The analyses provided by the experts upstairs are all very reasonable and worth learning from*. The main principle for controlling the level of waste boiler liquid is to ensure that the heat exchange tubes of the waste boiler are completely submerged in the boiler water ； Under the aforementioned conditions, its liquid level must not be too high to prevent liquid from being carried in the steam. As long as these two conditions are met, the control objective is achieved.
Have there been any simulation calculations related to obsolete boilers?
For high-pressure gas, is it low inlet and high outlet, or high inlet and low outlet? Is this related to the liquid level? If the liquid level becomes too high and submerges the heat exchange tubes inside, isn’t there a risk of liquid leakage? The liquid level is controlled at around 30 percent; what’s causing the leak in the waste boiler?
In our company, the liquid level in the waste pot is generally kept between 40% and 60%. If the level is too low, it can cause the synthesis system to shut down automatically; moreover, it easily leads to a dry pot condition. In such a situation, the pot must be cooled down to room temperature before water can be added again, which disrupts production. If it is too high, steam will carry water, causing liquid slugging in the piping system.
It is necessary to determine whether the first waste boiler is a drum boiler or a straight-through boiler, and whether it is a vertical or horizontal device, in order to determine the liquid level