Chinese exporters of PSA technology for hydrogen purification? 

When people talk about Chinese exports of gas separation technologies, many people immediately think about cheap equipment and copies. But in the segmentPSA for hydrogenIt’s been about five years since a different story began - not just the supply of adsorbers, but the export of entire technological solutions, moreover, with adaptation to the customer’s raw materials. I went through this myself when we were choosing a unit for modernization at one of the refineries in the CIS. The main misconception is that the Chinese only work on a turnkey basis. according to their own rigid patterns. In fact, if you find the right supplier, you can go into deep study of the cycle, right down to the selection of adsorbents for the specific composition of associated gas. But there are also plenty of pitfalls.

From adsorbers to technology packages: how the focus has shifted

Previously, years before 2017, Chinese companies often positioned themselves as manufacturers of columns and control units. That is, in essence, they were selling “iron?” with basic loop logic. Now the trend is licensing technology and designing for the client’s raw material conditions. This is especially important for hydrogen plants, where outlet purity is a critical parameter and the composition of the feed stream (for example, from methane reforming or cracking units) may vary.

We had experience with an installation at 40,000 Nm3/h. The Chinese engineer immediately requested not only the passport composition of the gas, but also data on possible impurities over the past two years - hydrogen sulfide, CO, humidity. They were interested specifically in “tails?” distribution in order to provide a reserve for the capacity of adsorbents. This is no longer the level of a seller, but a technology partner. The key word here isPSA adaptation, not just delivery.

True, not everything is so smooth. There were also companies that offered a “standard” one. project for hydrogen from conversion, although we had a stream from coke oven gas. The difference in CO and carbon dioxide content is significant, and if the sequence of adsorbent layers and cycle time are not adjusted, the purity of the output will be unstable. I had to refuse such offers.

What to look for in a proposal: hidden nuances of operation

One of the main points that is often missed when choosing a supplier is not the pressure or degree of purification (everyone declares them), but the details on the management and recovery of adsorbents. Chinese engineers from powerful companies like to delve into the valve control algorithm when releasing pressure. Not only energy efficiency, but also the service life of molecular sieves depends on this.

For example, in one of the projects fromChengdu Yizhi Technology Co.(this is their website - yzkjhx.ru) drew attention to their approach to stepwise pressure release in columns. They don’t just use a standard four-stage cycle, but provide the ability to calibrate the time of each stage directly from the operator panel, depending on the actual load. This is a small thing, but it greatly simplifies life at the start of operation, when you need to “catch?” mode.

Another practical nuance is recommendations on the frequency of replacing adsorbents. Some suppliers give an optimistic 10-12 years, but in conditions of high sulfur or moisture content in the raw materials, this period can be halved. It’s a good sign when the commercial proposal has a separate section with an analysis of the influence of specific impurities and a schedule for monitoring the activity of adsorbents. Chengdu Yizhi, in the description of their design institute (authorized capital of 120 million yuan, which indicates serious resources), emphasizes support and maintenance, and not just sales.

Case study: successful and not so successful integration

I'll tell you about two real cases. The first one is successful. It needed to be modernizedhydrogen purificationat a chemical plant. The feed stream is hydrogen-containing gas from a methanol plant. The key goal was to increase the purity from 99.5% to 99.999% for use in ammonia synthesis. A Chinese contractor (I won’t name it, this is not an advertisement) proposed not just adding an adsorption stage, but revising the entire drying and pre-treatment scheme for CO2. As a result, we made a hybrid scheme: first absorption with monoethanolamine, then with PSA. The PSA unit itself was compact, using compressed adsorbents, which saved space.

And now about the failure, or rather, about the problematic start. At another facility, a Chinese PSA unit was purchased to separate hydrogen from reforming gases. All parameters seemed to agree. But after three months of operation, problems with cleanliness began. It turned out that the original stream periodically “slipped?” aromatic vapors for which the standard zeolite in the adsorber was not designed. The supplier responded, but the solution was expensive - replacing part of the layers with a specialized adsorbent. Conclusion: even the most detailed specifications need to be supplemented with an analysis of “non-standard”, but possible components in the raw materials. Chinese engineers sometimes rely too much on the "average" ones provided to them. data.

In both cases, it was critically important to have on the supplier’s side not just a sales manager, but a technology center capable of quickly modeling the process and suggesting configuration changes. This is where structures such as the mentioned Chengdu Yizhi Technology, created by Huaxi Technology, have an advantage. They are initially tailored for design and research tasks, and not for conveyor sales.

Trends and pitfalls logistics and service

Now many Chinese exporters are actively developing service centers in regions, including the CIS. This is a big plus. But there is a nuance: often these centers have mechanical and automation engineers, but there are no deep specialists in adsorption technology. That is, they will help you replace a valve or sensor, but they won’t help you adjust the controller program to optimize the cycle when the load changes. When choosing a supplier, you should immediately clarify who and how will carry out commissioning and training of your technologists. Ideally, it is the chemical technologist who comes to the launch, and not just the installer.

Another point is spare parts. Valves for PSA are specific, with high requirements for response speed and tightness. Some Chinese manufacturers use their own valves, while others purchase them from specialized German or American brands. The second option is usually more reliable in the long term, but is more expensive and may be more difficult to deliver promptly. You need to understand this policy in advance and include it in the contract.

What we've seen recently is a push by Chinese players to offer digital twins of PSA installations for remote monitoring and predictive maintenance. It sounds progressive, but in practice the functionality is often limited to basic data collection. Only a few can boast of real analytics and recommendations for changing modes (that same “adaptation” in real time). You should not overpay for this option if you are not sure of its actual fullness.

Conclusions for those who are searching

So, to summarize. Chinese technology marketPSA for hydrogenceased to be a source of simply cheap equipment. This is an area where engineering competencies and the ability to flexibly solve client problems compete. When choosing a supplier, you need to look not at a beautiful catalog, but at the history of projects with a similar type of raw material, the presence of its own design and research department (like Chengdu Yizhi Technology Co., Ltd.), and, very importantly, the composition of the team that will lead your project from technical specifications to launch.

You should be prepared for the fact that it's perfect out of the box. there is no solution. Even the most advanced technology will require fine tuning on site. And here it is important that the supplier is committed to dialogue, and not just shipped equipment according to specifications. The successful projects that I have seen have always been the result of close collaboration between the customer's technologists and the supplier's engineers at all stages.

Ultimately, the success of implementing a Chinese PSA plant for hydrogen purification rests on three things: in-depth diagnostics of the feedstock, competent adaptation of the process flowsheet and the availability of real, rather than declarative, service support after delivery. If these points are closed, you can get a very effective and cost-competitive solution. If not, history risks turning into a long and expensive fight against “childhood diseases?” not a fully developed project.