【Q&A Question 054】2018.02.23
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【Q&A Question 054】February 23, 2018: What is the purpose of stopping the alkali washing? After the shutdown, H2S remains in the reaction system; it reacts with the oxygen that enters the system to form polythionic acids. These acids can corrode the equipment, causing cracks or pores at the welds, which leads to internal leakage and reduces the equipment’s service life. Alkaline cleaning of the reaction system can neutralize the polythionic acids and form a protective layer on the equipment. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Due to the limitations on the number of posts in the “One Question per Day” section, “One Image per Day” has been moved to the registered devices section; you can access it through the directory I posted. For management purposes, if you need to access content from a few days ago, please go to the summary post below to enter the “My Registration Season” event – (Note: This event is currently underway in the Chemical Engineering section). https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=18978 For the daily questions section related to chemical engineering technology training in 2018: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888971 For the daily image section related to registration equipment in 2018: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888970 For the Q&A section related to hydrogen production and hydrogenation technologies in 2018: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888968 For the daily questions section related to LNG technology in 2018: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1888973 For the Q&A section from 2017 (updates have started): https://bbs.hcbbs.com/thread-1657793-1-1.html For the daily questions section from 2017 (updates have started): https://bbs.hcbbs.com/thread-1657794-1-1.html For the daily image section from 2017: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1875160 For the list of daily questions related to LNG in 2017: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1804162 For the Q&A section from 2016 (updates are complete): https://bbs.hcbbs.com/thread-1597792-1-1.html
It should be passivated, to prevent ferrous sulfide from catching fire; both the high-grade and low-grade materials need to be passivated together.
Answer: After the shutdown, H2S remains in the reaction system; it reacts with the oxygen that enters the system to form polythionic acids. These acids can corrode the equipment, causing cracks or pores at the welds, which leads to internal leakage and reduces the equipment’s service life. Alkaline cleaning of the reaction system can neutralize the polythionic acids and form a protective layer on the equipment.
After shutdown, H2S remains in the reaction system; it reacts with the O2 that enters the system to form polythionic acids. These acids can corrode equipment, causing cracks or pores at the welds, which leads to internal leaks and reduces the equipment’s service life. Alkali washing of the reaction system can neutralize the polythionic acids and form a protective layer on the equipment.
Answer: After shutdown, H2S remains in the reaction system; it reacts with the oxygen that enters the system to form polythionic acids. These acids can corrode equipment, causing cracks or pores at the welds, which leads to internal leakage and reduces the equipment’s service life. Alkali washing of the reaction system can neutralize the polythionic acids and form a protective layer on the equipment.
After the shutdown, H2S remains in the reaction system; it reacts with the oxygen that enters the system to form polythionic acids. These acids can corrode the equipment, causing cracks or pores at the welds, which leads to internal leakage and reduces the equipment’s service life. Alkaline cleaning of the reaction system can neutralize the polythionic acids and form a protective layer on the equipment.
Alkaline cleaning is also commonly referred to as alkaline etching or alkaline ablation. The purpose of this treatment process is to further remove dirt from the surface and completely eliminate the natural oxide layer on the aluminum surface, thereby revealing the pure metal substrate and laying a good foundation for uniform electrical conductivity during subsequent anodization and the formation of a uniform anodized layer
After the shutdown, H2S remains in the reaction system; it reacts with the oxygen that enters the system to form polythionic acids. These acids can corrode the equipment, causing cracks or pores at the welds, which leads to internal leaks and reduces the equipment’s service life. Alkaline cleaning of the reaction system can neutralize the polythionic acids and form a protective layer on the equipment.
It should be passivated, to prevent ferrous sulfide from catching fire; both the high-grade and low-grade materials need to be passivated together.
Alkaline cleaning is also commonly referred to as alkaline etching or alkaline ablation. The purpose of this treatment process is to further remove dirt from the surface and completely eliminate the natural oxide layer on the aluminum surface, thereby revealing the pure metal substrate and laying a good foundation for uniform electrical conductivity during subsequent anodization and the formation of a uniform anodized layer.
After the shutdown, H2S remains in the reaction system; it reacts with the oxygen that enters the system to form polythionic acids. These acids can corrode the equipment, causing cracks or pores at the welds, which leads to internal leakage and reduces the equipment’s service life. Alkaline cleaning of the reaction system can neutralize the polythionic acids and form a protective layer on the equipment.