Layout of fire protection facilities in areas at risk of leakage of highly volatile and flammable materials
Thread Content
In a batch fixed-bed reactor area, multiple reactors are arranged side by side. Due to the frequent start-up and shutdown of these reactors, there are significant fluctuations in the temperatures at their inlets and outlets, which leads to frequent leaks at the flanges of these reactors as well as those of the associated heat exchangers. The materials that leak out are high-temperature, flammable, and explosive, posing a risk of fire and explosion. What should be done regarding the layout of fire protection facilities in this area, or what technical measures can be taken at the leakage points to reduce the risk of fire and explosion?
1. From a process perspective, it is necessary to address the issue of heat exchanger flange leaks caused by the frequent start-up and shutdown of various reactors； 2. Install fire-fighting equipment specifically at the locations where leaks occur frequently, taking into account the characteristics of the media involved ； 3. Prepare emergency plans and conduct regular drills ； 4. Strengthen control over areas where leaks occur frequently, and implement appropriate isolation measures for protection. ,
The reactor flanges are constantly leaking – what kind of production facility is this? Is it due to bubbling feeding or sealing issues? What are the properties of the material?
It should be controlled at the source; one shouldn’t think of dealing with it afterwards! Leakages are no small issue, especially since the substances involved are flammable and explosive. **The State Administration for Work Safety has issued relevant regulations: the \"Guiding Opinions of the State Administration for Work Safety on Strengthening Leak Management in Chemical Enterprises\" (An Jian Zong Guan San [2014] No. 94)**
Hello, thank you for your reply. We are working on a liquefied gas and naphtha aromatization project, and for the reactors, heat exchangers, and associated pipelines, 304H material is used. Since it is a fixed-bed reactor, the catalyst must be regenerated approximately once a month; this requires switching to the regeneration mode. During the start-up and shutdown processes, if the rate of temperature change is too slow, it can cause significant changes in the composition of the reaction products, which has a major impact on subsequent processing steps (such as the cold box). Therefore, it is difficult to reduce the rate of temperature change. The pipes at the inlet and outlet of the reactor, as well as the flange bolts of the heat exchanger, are all made of 304H, grade M30+, and our operating pressure is 0.5 MPa ； We are currently considering adding disc springs to the bolts in order to reduce the impact of temperature changes on the flanges. We’re not sure whether this approach will be effective. Additionally, we would like to know what benefits using a hydraulic wrench for tightening can bring in terms of reducing such leaks
Is the poster referring to leaks at the flange? Could you tell me what kind of gasket is being used?
Based on the description of the reactor you provided, the operating conditions are not particularly stringent, and it is considered a low-pressure device. Was the process regeneration an issue from the original design, or did it arise during later production? If it is a problem that arises later on, equipment calibration analysis is required. If the original design is like this, it is possible to consult the original design firm to find out how such a problem can be resolved. Hydraulic wrench tightening technology is primarily used for tightening high-pressure flange bolts; since these areas are subject to high temperatures and pressures, the leakage rate must be kept at an extremely low level. The bolts are tightened by calculating the appropriate torque.
Thank you for your reply. We have already consulted with the design firm and visited manufacturers of similar types; two of them encountered the same problem as us. The measures they took were to install disc springs on the bolts and add fire steam curtains around the flanges. The other conventional measures are more or less the same. Our current plan is to use disc springs first, as well as to install fire steam curtains throughout the areas prone to leakage.
It is recommended to post the photo so that everyone can learn together*.
It hasn’t been modified yet; we will carry out the major maintenance in April, and we’ll share the details with you once it’s completed.