Call for proposals on handling principles and methods for accident conditions such as oxygen cutoff in two-stage furnaces and other similar major unexpected abnormalities
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This post was last edited by Small and on 2017-9-10 01:20. It is a thread seeking principles and methods for dealing with situations such as oxygen interruption in two-stage reactors and other major unexpected abnormal incidents. Over the past year, as natural gas prices have dropped, methanol production plants that use natural gas have begun to operate again across various regions. In the natural gas to methanol process, the addition of pure oxygen in the second-stage furnace has a significant impact on the plant; not only does it affect the conversion rate of methane, but it also severely impacts the steam balance of the entire system. Therefore, addressing oxygen interruption in the two-stage furnace is most effective by approaching it from this perspective. Oxygen deprivation usually occurs suddenly, and a technical supervisor may not be present; it poses a severe test of the controller’s ability to react on the spot. What should be given up? What is to be protected at all costs? Do you have an idea of the future trend of the device’s operational status? These issues pose a significant challenge to the team leader’s overall perspective, as it is the team leader’s ability to take control of the device’s operation that determines the outcome of any actions taken. There are many similar typical accident handling scenarios, such as the shutdown of high-pressure boiler feed water pumps or interruptions in the hydrogen supply for cobalt-molybdenum hydrogenation processes. All experts are welcome to leave their comments.
This post was last edited by Small and on 2017-9-12 21:20. Let me start by talking about an atypical accident: a sudden loss of hydrogen supply during the operation of a cobalt-molybdenum hydrogenation process. The 400,000-ton per year methanol production plant is being commissioned; during this commissioning phase, the hydrogen supply comes from two ammonia synthesis units. Once operation is normal, the plant will rely on its own membrane separation system for hydrogen supply. One of the two ammonia synthesis units is under maintenance, while the other stopped operating suddenly. The 400,000-ton per year methanol plant has just completed the heating process of the synthetic nitrogen gas and is ready to send the conversion gas through the system, but it lacks a source of hydrogen for this process. I’ll recall the details carefully tomorrow and then send them.
This post was last edited by Small and on 2017-9-13 00:01. There are four sources of hydrogen for hydrogenation in this system; in addition to the hydrogen from the two ammonia synthesis units, there are two other sources. One of them is the membrane separation recycle stream, which serves as the source of hydrogen during normal operation. The other one is on the nitrogen circulation pipeline at the conversion outlet; it actually refers to the conversion gas. It is said that using this converted gas as a source of hydrogen is a \"genius idea\"; I’m not sure whether other new installations also feature this design. In any case, the converted gas can be used as a temporary hydrogen source. The installation of the fourth hydrogenation line was done in anticipation of extreme situations where the process isn’t started yet, and one set of external ammonia synthesis equipment needs to be overhauled while another stops operating. If the conversion process is already in operation, it allows the facility to hold on until the synthesis process is completed, after which hydrogen can be supplied again via membrane separation. Although there will be a period during which carbon buildup occurs, this is still acceptable. Unexpectedly, it was encountered within a few years; many people no longer knew where that valve was, as no one had ever touched it. In the end, everything turned out well and the system was brought out of danger. Soon, synthetic gas was generated, but then it reverted to membrane-based hydrogen production, with the converted gas being used for hydrogen production again. All these years have passed and it’s only happened once, haha; I really am unlucky.