China: prospects for PSA hydrogen purification? 

When you hear “PSA of hydrogen purification in China?”, the first thing that comes to mind is gigantic scale, endless construction projects and cheap equipment. But this is superficial. In fact, over the past 5-7 years there has been a quiet revolution in the understanding of the process. They no longer simply copy old UOP or Linde schemes, but actively adapt them to their own, sometimes unique, raw material flows and purity requirements. The main challenge now is not to make the installation, but to ensure that it works stably and economically in real, “dirty” conditions. Chinese hydrogen gas, where the composition can jump so much that any model in Aspen cries. Many projects have stumbled over this.

From theory to practice: where are the pitfalls?

Take, for example, a typical gas from a refinery reformer. Looks like a PSA classic. But Chinese refineries often operate on heavy, sour crudes, and traces of higher mercaptans or aromatics can slip through pre-treatment. For adsorbents this is death. I remember one project in Shandong, where six months after launch the purge pressure had to be changed almost manually every week - the adsorbent began to prematurely lose capacity due to impurities not taken into account in the technical specifications. We had to install an additional adsorption stage at the inlet, which ate up part of the profit. It turned out that the supplier of raw materials changed the batch of catalyst at the reformer, and the composition changed slightly, but critically.

Or another aspect - energy efficiency. In pursuit of lower capital costs, some local manufacturers have simplified the valve design and controls. As a result, hydrogen losses due to purging and re-compression were 10-15% higher than those of competitors. The customer pays less for installation, but then overpays for electricity for decades. This is a question of design culture, not just technology.

Here it is worth mentioning companies that have approached the issue systematically. For example,Chengdu Yizhi Technology Co.(their website isyzkjhx.ru), as a design institute that grew out of the chemical technology company Huaxi, often relies on deep customization. They don’t just sell a box with “PSA” written on it, but first conduct a long analysis of the raw materials in their own pilot plant. It's more expensive at the FEED stage, but then there are fewer surprises. Their approach is precisely a consequence of the accumulated experience of working with capricious Chinese raw materials.

Market and drivers: what drives demand besides refineries?

Yes, traditionally the engine has been oil refining and ammonia production. But now new powerful drivers are emerging. Firstly, it is synthesis gas from coal (CTO, coal-to-olefins). There, huge volumes of hydrogen are needed, and it is often recovered from the CO-rich stream. PSA units here operate at the limit of selectivity; there is a constant struggle for the purity of H2 and to reduce its losses with waste gas. The installations are colossal, 200-300 thousand Nm3/h and more.

Secondly, and this is the most interesting thing, hydrogen energy. So far we are mostly talking about “blue?” hydrogen from natural gas with CO2 or associated gases captured. In provinces rich in renewable energy sources, pilot projects are beginning to appear to combine electrolysis and PSA to purify hydrogen from oxygen and moisture. The purity requirements here are prohibitive, 99.999% and higher, but the volumes are still small. It's more of a testing ground for technology.

Thirdly, metallurgy. Hydrogen as a reducing agent is a trend. But gases from coke ovens or converters are a hell of a mixture. Development is ongoing, but I have not yet seen commercial PSA projects for such conditions in China. More talk and R&D.

Technology Trends: Where is Engineering Heading?

The main trend is hybridization. PSA alone often fails. That’s why you increasingly see schemes like “absorption + PSA?” or “membranes + PSA?”. For example, for deep cleaning from CO2, an amine wash is installed before the PSA. This increases complexity, but dramatically increases the reliability and service life of the adsorbents. This is especially true for gases with high CO2 partial pressure.

The second is intelligent control. Not PID controllers, but systems capable of adapting to changes in the composition of raw materials in real time, predicting the moment of impurity breakthrough and optimizing the cycle. Chinese engineers here are actively experimenting with machine learning algorithms, training them on historical data from operating installations. UChengdu Yizhi Technology, by the way, in the description of their approaches as a design institute, one can feel this emphasis on integrated design and life cycle management, and not on the sale of equipment.

The third point is materials. Development of new, more capacious and selective adsorbents for specific impurities. Chinese scientific institutes and companies like Huaxi (parent of Yizhi) publish a lot of articles on modified zeolites and carbon molecular sieves. The question is how quickly these developments will leave the laboratories and enter commercial columns.

Economy and the future: is the game worth the candle?

The prospects are enormous, but so are the risks. China is building dozens of new refineries and chemical complexes, and almost every one has aHydrogen cleaning PSA. The market for engineers and suppliers is a bonanza. However, the competition is tough. Prices are pressing, project deadlines are being compressed. In pursuit of a winning tender, some make dangerous simplifications.

On the other hand, the demand for service, modernization and digitalization of existing installations is growing. This is where real experience is needed, and not just the ability to make a drawing. Companies that can not only build, but also “tweak” a working unit, increasing its hydrogen recovery by a couple of percent, will be in demand.

As for ?green? hydrogen, PSA will remain a critical purification technology. But her role may change. Perhaps more compact, fast and flexible modular solutions for distributed energy will appear. This is already a challenge for traditional suppliers accustomed to giant stationary units.

As a result, there are prospects, and they are associated not with thoughtless replication, but with deepening into details, adaptation to complex raw materials and integration into broader technological chains. Those who understand this, like the same team from Chengdu, will remain afloat. The rest may become suppliers of cheap but problematic hardware, the reputation of which will circulate throughout the market in the form of terrible tales from operators.

Personal observation: operating culture as a key factor

In conclusion, I want to say something that is rarely written about in technical articles. The most advanced PSA unit can be ruined in a month by improper use. In China, I saw amazingly organized control centers at new factories, where operators understand the nuances of the cycle better than other engineers, and a terrifying picture at old factories, where valves are leaking, and the control logic is broken and no one is repairing it.

Therefore, the future of technology here depends not only on design engineers, but also on personnel training and knowledge transfer. Design institutes that include lengthy commissioning and training in their contracts benefit in the long run. Because their installations then work like clockwork, and the client returns.

So it turns out that the question of PSA’s prospects in China is not a question of “what?”, but “how?”. How they will design, how they will adapt, how they will serve. The technology is proven, world-class. But local specifics and the depth of its elaboration are the very field on which the real struggle is now taking place. And judging by some projects, Chinese specialists are gradually winning this battle, gaining their own unique experience.