AC operation of the three-in-one graphite hydrochloric acid synthesis furnace
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The plant is equipped with three sets of identical three-in-one hydrochloric acid synthesis furnaces of the Nantong Huanaitai model, namely A/B/C (furnace structure comprising synthesis section, cooling section, and absorption section); an exhaust gas absorption tower using pure water for absorption; and an exhaust gas alkali scrubbing tower to control the exhaust gases). Furnace C operates most stably, followed by furnace B, while furnace A presents unresolved issues. Operation issue 1: The factory is located in the south, and the hydrogen entering the furnace contains saturated condensate water; therefore, frequent drainage through the drain lines is necessary. There is a plan to improve the heat exchange efficiency of the hydrogen cooler located before the furnace, with the consideration of adding an automatic system for removing condensate water.Operation issue 2: The flow meters for chlorine and hydrogen in the three furnaces exhibit significant deviations. When the ratio of hydrogen pressure (36 kPa) to chlorine pressure (100 kPa) is around 2, a slight decrease in hydrogen pressure results in the formation of free chlorine, making it difficult to achieve proportional automatic control.
Operation issue 3: During the startup process, Furnaces A and B often experience a sudden drop in hydrogen flow, along with an increase in the acid flow temperature by more than 50°C; Furnace C does not have this problem ； A sudden drop in hydrogen flow indicates a fault with the control valve or the flow meter; it is suspected that the chlorine-to-hydrogen ratio control is unbalanced, with an excess of hydrogen preventing its entry, as well as excessively high temperatures in the acid absorption process. Issue 4: After operating stably for a period of time, Furnace A’s chlorine and hydrogen flows will suddenly drop to 0, triggering an emergency shutdown mechanism ； This has not happened in BC furnaces. Have any experienced professionals in this field encountered the third or fourth issue? Please share your insights – how is it possible to have no traffic at the same time? :dizzy:. . . .
Regarding the third issue, the sudden drop in hydrogen flow rate suggests that it is necessary to check the entire gas supply system, including pipes and valves, for any blockages or leaks, as these can cause unstable gas supply. At the same time, considering the possibility of insufficient pressure at the gas supply source, it is necessary to check and adjust the pressure at the source of gas supply. Regarding the fourth question, the chlorine and hydrogen flow rates in Furnace A were both reduced to 0; this situation may be related to the supply stability of the gas supply system. It is necessary to check all the components in the gas supply line to ensure that they are functioning properly, including pressure regulators, flow meters, valves, etc. Additionally, consider whether there is a fault in the electrical control system that could lead to erroneous operations or wrong signals triggering the shutdown interlock. It is recommended to conduct a comprehensive system diagnosis to check for any issues with the interaction between the control system and the gas supply system. Both of these issues are related to the stability of the gas supply and control systems; it is recommended to conduct comprehensive inspections and maintenance from these two aspects. .
Thank you for your reply! In our factory, basically two furnaces operate simultaneously; when such a problem occurs with Furnace A, the other one still functions normally. The valves and instruments related to the gas supply have been checked and found to be in good condition. When both the chlorine and hydrogen flow rates dropped to 0, the backend data showed that there was no flow first, and only then did the flame-out interlock mechanism close the gas inlet valve. Therefore, we suspect that the hydrogen that could not be completely burned got trapped and could not escape, resulting in the furnace pressure rising above the pressure of the gas supply and the gas inlet flow rate dropping to 0 suddenly.
If the hydrogen flow rate decreases, is it possible that the hydrogen lamp nozzle is blocked?
Is it possible that all these problems are caused by the first issue? With such a high level of water in the hydrogen gas, could this lead to blockages in the pipelines? Could it affect the readings of the flow meter? Given that the ratio of hydrogen to chlorine flow rates is so high, have you considered the possibility that it might be a problem with the choice of flow meter?
Personally, I think we should give more consideration to the impacts caused by the high water content in hydrogen
Pay special attention to water accumulation in hydrogen pipelines. When water flows through, water blockages can easily occur in the flame arrester or at other locations.
This post was last edited by freegoto on 2025-3-3 at 12:02. Regarding the issue of \"Problem 2: The flow meters for chlorine and hydrogen in the three furnaces show large deviations; when the ratio of hydrogen (36 kPa) to chlorine (100 kPa) is around 2, a slight reduction in hydrogen pressure results in the formation of free chlorine, making it difficult to achieve automatic proportional control\", there are two suggestions: 1. The ratio should not be based on pressure, but rather on flow rates; 2. A cascade control system can be used, with a detector to monitor the hydrogen level in order to adjust the ratio
For suggestions 3 and 4, it is also advisable to check whether the hydrogen flame arrester is clogged