炼化尾气发电机组，氢气泄漏报警阈值到底是多少？

　　What is the threshold for hydrogen leakage alarm in the refining tail gas generator set?

　　做炼化行业的朋友们，尤其是接触高氢炼化尾气发电机组的，肯定都有一个关键疑问：氢气泄漏报警阈值到底设多少才安全？很多人可能听过铅酸蓄电池充电会产生氢气，却不知道高氢炼化尾气发电机组的氢气泄漏风险，比蓄电池大多了，一旦阈值设错、报警不及时，后果不堪设想。今天就实打实地跟大家唠明白，结合氢气的爆炸特性、炼化现场的实际情况，把报警阈值的事儿说透，不玩专业术语，新手也能一看就懂。

　　Friends in the refining industry, especially those who come into contact with high hydrogen refining tail gas generators, must have a key question: what is the safe threshold for hydrogen leakage alarm? Many people may have heard that charging lead-acid batteries produces hydrogen gas, but they do not know that the risk of hydrogen leakage in high hydrogen refining tail gas generators is much higher than that of batteries. Once the threshold is set incorrectly and the alarm is not triggered in a timely manner, the consequences can be unimaginable. Today, let me explain to you in detail the alarm threshold based on the explosive characteristics of hydrogen gas and the actual situation at the refining site. Even beginners can understand it at a glance without using professional terminology.

　　先跟大家铺垫一个核心知识点，不管是铅酸蓄电池产生的氢气，还是高氢炼化尾气泄漏的氢气，其爆炸特性都是一样的。按理论计算，氢气在空气中的爆炸极限是4.0%到75.6%（体积浓度），这句话通俗点说就是：如果氢气在空气中的体积占比，落在4.0%到75.6%这个区间，只要遇到一点火花--比如发电机组运行产生的电火花、现场的静电，就会发生爆炸；但如果浓度低于4.0%，或者高于75.6%，哪怕有火源，也不会爆炸。

　　First, let me lay the foundation for a core knowledge point. Whether it is the hydrogen gas generated by lead-acid batteries or the hydrogen gas leaked from high hydrogen refining tail gas, their explosive characteristics are the same. According to theoretical calculations, the explosion limit of hydrogen in air is 4.0% to 75.6% (volume concentration). Simply put, if the volume fraction of hydrogen in air falls within the range of 4.0% to 75.6%, an explosion will occur upon encountering a spark, such as the electric spark generated by a generator set or static electricity on site; But if the concentration is below 4.0% or above 75.6%, even if there is a fire source, it will not explode.

　　可能有朋友会说，那报警阈值设4.0%不就行了？刚好卡在爆炸极限的最低值，既不浪费，又能报警。这种想法真的大错特错，尤其是高氢炼化尾气发电机组，绝对不能这么设！大家别忘了，铅酸蓄电池充电产生的氢气，释放速度慢、浓度上升平缓，而高氢炼化尾气发电机组，一旦发生泄漏，氢气会快速扩散、积聚，而且炼化现场大多是密闭或半密闭空间，通风条件有限，浓度会在短时间内飙升，等达到4.0%再报警，根本来不及处置，瞬间就可能引发爆炸。

　　Some friends may say that setting the alarm threshold to 4.0% is enough? It happens to be stuck at the lowest point of the explosion limit, which is neither wasteful nor alarming. This idea is really wrong, especially for high hydrogen refining tail gas generator sets, which cannot be set up like this! Don't forget that the hydrogen gas generated by lead-acid battery charging has a slow release rate and a gradual increase in concentration. However, in the case of a leak in a high hydrogen refining tail gas generator set, hydrogen gas will rapidly diffuse and accumulate. Moreover, most refining sites are enclosed or semi enclosed spaces with limited ventilation conditions, and the concentration will soar in a short period of time. When it reaches 4.0%, an alarm will be issued, and there is no time to dispose of it, which may cause an explosion in an instant.

　　而且高氢炼化尾气中，除了氢气，还夹杂着其他可燃、有毒气体，氢气的扩散速度又极快，比空气轻很多，容易积聚在设备顶部、角落等隐蔽位置，很难被发现[1]。再加上发电机组运行时，本身就有高温、电火花等火源，泄漏的氢气一旦达到爆炸极限，爆炸的威力极大，不仅会损毁发电机组，还会波及整个炼化车间，造成人员伤亡和巨额财产损失，之前就有企业因为阈值设得过高，延误了报警时机，吃了大亏。

　　Moreover, in the tail gas of high hydrogen refining, in addition to hydrogen, other flammable and toxic gases are also mixed in. The diffusion speed of hydrogen is extremely fast, much lighter than air, and it is easy to accumulate in hidden positions such as the top and corners of equipment, making it difficult to detect. In addition, during the operation of the generator set, there are already sources of ignition such as high temperature and electric sparks. Once the leaked hydrogen gas reaches the explosive limit, the power of the explosion is extremely strong. It will not only damage the generator set, but also affect the entire refining workshop, causing casualties and huge property losses. Previously, some companies had delayed the alarm timing due to setting the threshold too high, resulting in significant losses.

　　结合《石油化工可燃气体和有毒气体检测报警设计标准》（GB/T 50493-2019）和高氢炼化现场的实际风险，今天就给大家一个明确的答案--高氢炼化尾气发电机组的氢气泄漏报警阈值，常规设置为低报0.8%-1.0%、高报1.6%-2.0%（均为体积浓度）。这个数值不是随便定的，每一步都有讲究，既兼顾了安全，又避免了误报警。

　　Based on the "Design Standard for Combustible Gas and Toxic Gas Detection and Alarm in Petrochemical Industry" (GB/T 50493-2019) and the actual risks of high hydrogen refining sites, today we will give you a clear answer - the hydrogen leakage alarm threshold for high hydrogen refining tail gas generator sets is usually set to a low alarm of 0.8% -1.0% and a high alarm of 1.6% -2.0% (both volume concentration). This value is not arbitrarily set, and every step is carefully considered to ensure safety and avoid false alarms.

　　先说说低报阈值（0.8%-1.0%），为啥设这么低？核心就是为了预留处置时间。这个数值远低于4.0%的爆炸下限，一旦报警，说明现场已经有氢气泄漏，但浓度还很低，处于安全可控范围，工作人员有充足的时间去排查泄漏点--比如检查发电机组的管道、阀门、密封件，关闭相关阀门、加强现场通风，把泄漏隐患及时消除，避免浓度继续上升。

　　First, let's talk about the low reporting threshold (0.8% -1.0%). Why is it set so low? The core is to reserve time for disposal. This value is far below the explosion lower limit of 4.0%. Once an alarm is triggered, it indicates that there has been a hydrogen leak on site, but the concentration is still very low and within a safe and controllable range. The staff have sufficient time to investigate the leak point, such as checking the pipes, valves, and seals of the generator set, closing relevant valves, strengthening on-site ventilation, and promptly eliminating the leakage hazard to prevent the concentration from continuing to rise.

　　再说说高报阈值（1.6%-2.0%），这是一道紧急警戒线。一旦触发高报，说明氢气泄漏量在增加，浓度已经接近爆炸下限的一半，风险急剧升高，此时必须立即启动应急措施：停止发电机组运行，切断氢气来源，疏散现场人员，启动防爆通风设备，直到氢气浓度降至低报阈值以下，才能进行后续的排查和维修。

　　Speaking of the high reporting threshold (1.6% -2.0%), this is an emergency warning line. Once a high alarm is triggered, it indicates that the amount of hydrogen leakage is increasing and the concentration is approaching half of the lower explosive limit, with a sharp increase in risk. At this time, emergency measures must be immediately activated: stop the operation of the generator set, cut off the hydrogen source, evacuate on-site personnel, start explosion-proof ventilation equipment, and wait until the hydrogen concentration drops below the low alarm threshold before proceeding with subsequent investigation and maintenance.

　　这里必须跟大家强调一点，高氢炼化尾气发电机组的氢气泄漏报警，绝对不能省略，就像铅酸蓄电池必须装氢气浓度报警器一样，这是底线要求[1]。而且报警器的安装位置也有讲究，要装在氢气容易积聚的地方，比如发电机组的顶部、管道接口附近，还要定期校准，避免设备老化导致阈值漂移、误报警或不报警，毕竟报警器失灵，再合理的阈值也没用。

　　It must be emphasized here that the hydrogen leakage alarm of high hydrogen refining tail gas generator units cannot be omitted, just like lead-acid batteries must be equipped with hydrogen concentration alarms, which is a bottom line requirement [1]. Moreover, the installation location of the alarm also has its own requirements. It should be installed in a place where hydrogen gas is prone to accumulate, such as the top of the generator set or near the pipeline interface. Regular calibration is also necessary to avoid threshold drift, false alarms or no alarms caused by equipment aging. After all, if the alarm fails, even the most reasonable threshold is useless.

　　还有很多朋友会问，不同厂家的发电机组，阈值能不能不一样？其实常规情况下，低报0.8%-1.0%、高报1.6%-2.0%是通用标准，适合大多数高氢炼化尾气发电机组。如果现场通风条件特别好，或者氢气泄漏风险相对较低，可在专业人员指导下微调，但绝对不能高于2.0%；如果是密闭空间、泄漏风险高的场景，建议适当降低阈值，确保安全冗余。

　　Many friends may ask, can the threshold be different for generator sets from different manufacturers? In fact, under normal circumstances, a low report of 0.8% -1.0% and a high report of 1.6% -2.0% are universal standards that are suitable for most high hydrogen refining tail gas power generation units. If the ventilation conditions on site are particularly good or the risk of hydrogen leakage is relatively low, it can be fine tuned under the guidance of professionals, but it must not exceed 2.0%; If it is a confined space with high leakage risk, it is recommended to lower the threshold appropriately to ensure safety redundancy.

　　最后再跟大家总结一句，高氢炼化尾气发电机组的氢气泄漏报警阈值，核心是“提前预警、预留处置时间”，不是卡在爆炸极限上投机取巧。记住这个标准：低报0.8%-1.0%、高报1.6%-2.0%，装好用好氢气浓度报警器，定期校准、及时排查，才能避免氢气泄漏引发的爆炸风险。

　　Finally, to summarize with everyone, the hydrogen leakage alarm threshold of high hydrogen refining tail gas generators is based on "early warning and reserved disposal time", rather than being stuck at the explosion limit and taking shortcuts. Remember this standard: low report 0.8% -1.0%, high report 1.6% -2.0%. Install and use hydrogen concentration alarms properly, regularly calibrate and promptly troubleshoot to avoid the risk of explosion caused by hydrogen leakage.

　　做炼化行业，安全永远是第一位的，多花点心思搞懂报警阈值，提前做好防范，比事后补救强一万倍。希望今天的分享，能帮到做高氢炼化尾气发电机组相关工作的朋友们，再也不用为报警阈值发愁，守住安全底线，才能守住生产线、守住家人的牵挂。

　　In the refining and chemical industry, safety is always the first priority. Spend more time to understand the alarm threshold and take precautions in advance, which is 10000 times better than remedial measures afterwards. I hope today's sharing can help friends who are working on high hydrogen refining tail gas power generation units no longer have to worry about alarm thresholds. Only by guarding the safety bottom line can we protect the production line and the concerns of our families.