Piston-type process compressors: FAQs
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This post was last edited by zhangqi1234 on 2017-10-13 at 16:11. University graduated from: Graduated from the School of Mechanical and Thermal Engineering at Xi’an Jiaotong University in 2010, majoring in Compressor Engineering. Specialized skills: piston compressors, simple chemical and gas processing processes, basic instrumentation engineering. Work experience: 2012–2017 – Worked in design at a domestic compressor manufacturer. I parted ways with the company on August 25, 2017, and am not planning to look for a job for now. I had wanted to discuss this with Hai Chuan and 707 for almost 10 years, always fearing it might be considered advertising; now that I’ve left my job, I’m free to do so, so I’m discussing it with my diving friends. PS: Actually, it’s more of a discussion aimed at helping each other improve rather than just answering questions. Additionally, I will keep updating this post by uploading more materials in the future. High-quality materials are those that do not reveal any secrets and contain useful information. Key achievements during the work period: Designed what is believed to be the first set of skid-mounted equipment in China for the separation and recovery of propylene, C4, hydrogen, nitrogen, and four types of mixed gases ； Independently design a non-labyrinth BOG cryogenic compressor ； Participation in the surveying, mapping, and replication of three series of American KNOX WESTERN compressors ； Companies that have developed their own natural gas engine test benches include: Wuxi Diesel Engine, Wuxi FAW Engine, Anqing CSSC Diesel Engine, Jinan Zhangqiu CNHTC Diesel Engine Factory; before leaving the company, negotiations were in progress with Luotuo Diesel Engine Factory ； Several sets of wellhead gas purification and recovery units have also been designed ； Daily or weekly online time: 8:00~22:00, but response times are not fixed ； Messages can be left at QQ94134625 in the evening. Work experience: 8 years. (If you have different opinions, please post a new topic in the rotating equipment discussion area; after all, there are differences between people.) In front of real experts, I’m still just a beginner; thanks for your cooperation.）
Knox compressors are geared towards medium to high-speed natural gas compressors, with relatively low power levels; the maximum capacity is 4 stages, around 1000 KW. As for the TP model you are attempting to replicate (60-65-75-90-100-120-145-200-220-245-400-445)
Hello, nowadays compressors are equipped with variable-speed control systems to save energy, allowing the load on each stage to be adjusted from 0 to 100. Compressors are designed with consideration for axial force balance; however, the use of such variable-speed systems can sometimes result in unusual noises at the installation site. How can we ensure the normal operation of the compressor? Can this be achieved through the compression ratio?
The load regulation methods I am familiar with include variable frequency control, switchback control, proportional backflow control, and unloader regulation. I think the so-called stepless regulation you mentioned is a type of unloader regulation that allows for stepless adjustment from 0 to 100. However, I have not heard of a method that enables stepless regulation at any single level; it is theoretically difficult to achieve this. For example, with a differential cylinder arrangement, if a stepless adjustment from 0 to 100 is to be achieved using the regulation system you mentioned, it becomes impossible to maintain balance between the piston forces on the shaft side and the cover side. Unless the base components are chosen to be significantly enlarged, the production cost will become exorbitantly high, making it not worth it.
The stepless control system for reciprocating compressors from Herbig: the three-stage reciprocating compressor is equipped with three manual controls for stepless adjustment, allowing compression to be carried out at each stage
Why are the air valve arrangements in compressors still of the upper and lower type? The upper ones are fine, but it’s very inconvenient to service those at the bottom.
The unloader equipped with a position sensor – only Holbig makes this product; no one else produces it. If that’s what you’re referring to, I understand now. It’s still an unloader for adjustment, only one that is highly automated. Its components include a pneumatic diaphragm, a position sensor, manual unloading elements, and a remote control unit. Moreover, it’s not a regulation from 0 to 100 in terms of load; rather, it’s possible to adjust the displacement from 0 to 100. However, adjustment at any specific stage isn’t feasible. Only multi-stage compressors with double-acting cylinders arranged separately for each cylinder stage can allow adjustment at any stage. For example, a V-shaped arrangement of cylinders on one floor cannot be used for such adjustment, as this would result in a gas force imbalance between the shaft side and the cover side.