【JST-021】One-on-one consultation office for experts in cryogenic air separation/natural gas liquefaction technology
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This post was last edited by Firefly on 2015-4-10 08:25. Specializations: Cryogenic air separation, natural gas liquefaction process design. Work experience: 8 years. Online hours: Monday to Friday, 9:00–17:00. I am often on business trips, but I will respond as quickly and thoroughly as possible. Special note: 1) This post mainly discusses issues related to manufacturing processes, allowing everyone to exchange ideas and improve together. 2) This post is intended for one-on-one discussions between those seeking help and those who are experts in this technology; other users are not allowed to discuss it here. If you have different opinions, please create a new thread in the Air Separation Technology discussion area. Thank you for your cooperation!
Currently, regular packing is basically used in the upper columns of air separation units. But for a project I’m working on now, sieve plates are used in the area above the argon extraction port in the middle and in the section where the expanded air enters the tower. A problem arises: in the design, the pressure drop across the upper tower should be as low as possible. But why is a sieve plate chosen for this section?
The technology of installing approximately 5 sieve trays above the argon fraction extraction point in the upper tower is based on Praxair’s technology from the United States; it was used in domestic projects between 2002 and 2006. Its main purpose is to take advantage of the high liquid holding capacity of sieve tray towers in order to improve the stability of the argon fraction, and temperature monitoring is usually also required. However, the actual performance was not significant, and additional investment was required, so it was rarely used after 2006.
This post was last edited by shenyu0 on 2012-3-30 at 10:49. It is planned to replace the stop valves, throttle valves, safety valves, and valve actuators located outside the cold box of the 6500 oxygen production distillation tower (based on Hangyang’s design from 2001; these valves are situated on the outer wall of the cold box and are severely damaged by acidic rain in the environment)； What guidelines should be noted? The manufacturer says it can be replaced directly after shutting down the machine.
Should gas-phase connectivity be considered when loading liquid nitrogen? Thank you
You mean that the tank truck is connected to the storage tank’s gas system, right? The main purpose of this connection is to recover the gaseous substances. In the LNG industry, it’s necessary to consider the recovery of BOG, but this practice is not common in the air separation industry. Firstly, there’s little benefit to such recovery (unless a filling device is installed, especially for argon), and secondly, releasing the gas directly poses no safety issues. I believe that gas connectivity is limited to the process of installing a charging pump, and is not applicable to the self-pressurization charging process using storage tanks.
If you merely want to replace the valve and accessories, simply purchase a valve with the same pipe size; then decide based on the situation whether flaw detection, pressure testing, or cold testing is required. If you want to consider corrosion protection, special requirements will apply to the materials and paints; it is recommended that you consult SH3022 \"Technical Specifications for Corrosion Protection Coatings on Petrochemical Equipment and Pipelines.\" This will, however, result in increased costs and longer delivery times.
Where can I find the isothermal adsorption curves for molecular sieves? Thank you!
At present, no molecular sieve manufacturers can provide adsorption curves; I’m sorry I can’t help you. When our company first started manufacturing adsorbers in the early 1990s, there were many charts, but unfortunately they weren’t preserved.
I have a question. I just graduated and have been working in the field of natural gas liquefaction. I would like to ask you for advice on how to gradually become a competent engineer – where should I start, what should I learn every day? Any guidance would be greatly appreciated. Thank you
Haha, it really depends on the individual; everyone has a different path of growth, and their methods of learning also vary. Today’s technicians all have at least a university degree, meaning they possess a basic theoretical foundation; what’s lacking is experience and knowledge in systematizing engineering projects, and this can only be acquired by learning more, observing more, thinking more, and asking more questions. You can start by reading Professor Gu Anzhong’s introductory book, \"Liquefied Natural Gas Technology\", and at the same time examine your company’s process flow diagrams. Then focus on each component in detail using the operation manuals – for example, the process, principles, and operating methods of the decarburization system, as well as the principles and operating methods of heat transfer oils. After understanding the basic process, you can try to conduct simulated calculations to understand the mutual influence of various parameters and gain a deeper insight into the manufacturing process. Finally, spend more time on-site to gain a more intuitive understanding of various machines and equipment. Good luck to you~~~