Why can’t the excess steam condensate be discharged?
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We have been modifying our system here to increase its production capacity. After the modifications, we realized that we had overlooked one issue: there was an excess of steam condensate that couldn’t be removed. This led to high pressure in the high-pressure expansion tank, and the liquid level in the separation tank didn’t drop, as a result of which the temperature in that tank couldn’t be increased and it was not possible to increase the amount of fluid being processed. We would appreciate it if fellow professionals could share their opinions on how this problem of unable to remove the water can be solved
Are there any foreign objects blocking the valves and control valves for discharging steam condensate?
Everything has been checked and there are no issues. The possible causes could be high pressure in the high-pressure expansion tank, a condensate temperature of 120 degrees, and the condensate pump not functioning properly. What could be causing the high pressure?
First, check for high pressure: 1. Are there any leaks (or openings) in the bypass lines of each heater? 2. Are the steam traps of each heater functioning properly? 3. Has the pressure on the steam side of each heater increased? Higher pressure means a higher saturation temperature of the water. Next, investigate why the water cannot flow out: 1. Is the pumping capacity of the water pump sufficient? 2. Are there any blockages in the inlet/outlet pipes of the water pump (are the pipe diameters adequate)? 3. Is the water pump capable of handling hot water? 4. Are the downstream units that receive the water operating properly? This is for reference only. Finally, examine the process design: when expanding production, was consideration given to the disposal of condensate water, and is the design reasonable?
If it is operated at the load level before your modifications, there will be no problem. It indicates that the pipeline is fine. Problems that occur under load may be due to inadequate design, pipe size, pump flow rate, and other factors.
Reply to 4# Xishui: We overlooked this issue during the renovation; the pump is fine and the pipes are not clogged. Here, a portion of the condensate flows to the high-pressure expansion tank, the liquid from that tank goes to the low-pressure expansion tank, and the water from the low-pressure expansion tank is sent to the thermal power plant. The problem is that the pressure in the low-pressure system is high and there is plenty of water, which prevents water from flowing into the high-pressure system. What can be done to address this high pressure?
It’s actually not bad, but the condensate water can’t be drained. The biggest problem is that the temperature of the heater doesn’t increase after expanding production. The pipes are fine, and so are the pumps; it is recommended to add another water pump, or use two pumps simultaneously, or replace the existing pump with one having a larger impeller. But what if the pressure in the low-pressure condensate tank is high? Perhaps the pressure will drop once the liquid level decreases. This is just for reference.
A high pressure in the low-pressure expansion tank is likely due to a too-small or clogged steam outlet valve, which results in high pressure; as a result, less secondary steam is generated from the condensate, causing the condensate level to rise.
Is there too much condensate returning to the low-pressure expansion tank? Find ways to use temporary measures to reduce the pressure and see if there is any improvement.
Right now, pressure is being relieved by releasing it on-site, but that’s not a solution either
Is there a pressure gauge on the low-pressure expansion tank? Can you install a pressure gauge to check it? What is the pressure on the high-pressure expansion tank? What is the low pressure? What is the relative elevation difference between the high-pressure expansion tank and the low-pressure expansion tank? Is it related to the bit difference? If the pressure difference between high and low pressure is too small to compensate for the positional difference on both sides, it also has an impact on the flow. (Are your two expansion tanks pressurized by themselves?) ) Is the pump you are referring to installed at the bottom of the low-pressure expansion tank? How is the pressure gauge at the pump outlet? What does it mean by saying that it doesn’t show a reading? Is the outlet pressure low, or is there air locking? Let me explain in more detail so everyone can use it as a reference. It’s best to draw a diagram.