China: hydrogen from hydrocarbons - technology and ecology? 

When people talk about hydrogen in China, many people immediately imagine “green”. electrolysis. But the reality on earth, especially on an industrial scale, is still different. The main volume is still hydrogen from hydrocarbons, and here lies a lot of nuances that are often hushed up in industry reports. I myself have worked on several projects on steam methane conversion, and I can say: the conversation about ecology here cannot be reduced to simple slogans. It's a constant trade-off between economics, available technology, and that carbon footprint that everyone is now so vehemently concerned about.

Technological basis: not only SMR

Yes, steam methane reforming (SMR) is a classic. But in China it is being implemented with adjustments to local raw materials. We often work not with ideal natural gas, but with associated petroleum gas or even coke oven gas. The composition is unstable, hence the headache with catalysts. I remember a project in Shanxi, where, due to the high sulfur content in the raw materials, the pre-treatment scheme had to be completely revised. Standard solutions were not suitable; as a result, a hybrid system was developed with adsorbents based on zinc oxide and zeolites. Efficiency has reached the level, but the service life of the conversion catalyst is still reduced by 15%. This is the price of adaptation.

Partial oxidation (POX) is a different story for heavy feedstocks. The technology is energy-intensive and requires a complex and expensive oxygen unit. But in some cases you cannot do without it. At one of the refineries in Liaoning, they were just introducing a POX unit for processing tar. The main problem was not even in the process, but in the accompanying equipment - heat-resistant alloys for the reactor and heat exchangers. Constant problems with corrosion and erosion. Chinese analogues did not always hold up; expensive imported materials had to be purchased, which negated the economic benefits of the project at first.

There is currently a lot of buzz around autothermal reforming (ATR) as a more flexible technology. It is said to be better in terms of hydrogen yield and emissions. On paper - yes. But in practice, the key is precise control of the oxygen/steam/feed ratio. The slightest failure and instead of the optimal process you end up with either soot or unconverted methane. I saw an attempt to launch such an installation at a pilot complex. The control system was "sharpened" under ideal laboratory conditions, but in reality, pressure fluctuations in the gas line ruined everything. It took a month to fine-tune the algorithms. So the technology is promising, but still requires a lot of “running in”. in the field.

Ecological Paradox and the CCS Trick

This is the main stumbling block. Producing hydrogen from methane inevitably produces CO2. Many. Therefore, now all projects in China that claim to be “low carbon” come with the prefix “CCS-ready?” or ?carbon captured?. But readiness is one thing, and actual implementation is another. The main problem is not even the capture technology (although it is expensive), but logistics and storage. Where should this CO2 go? There are not many geological formations for storage on an industrial scale near factories.

Was involved in project evaluationhydrogen from hydrocarbonswith full cycle CCS in Xinjiang. Technically, everything is calculated: 90% capture, a pipeline to transport CO2 150 km to a depleted gas field. But the economy is shaky. The cost per ton of CO2 captured and buried eats up all the potential profits from “clean” CO2. hydrogen. The project was eventually frozen, awaiting greater government subsidies or higher prices for carbon quotas. So far, CCS in China is more of a demonstration project than a mass practice.

Another point is indirect emissions. Everyone counts the carbon from the conversion process itself, but they often forget about the “gray” part. footprint from the production of electricity for the operation of compressors, pumps, control systems. If the plant is located in a region where the network is connected to coal, then the overall emissions picture worsens by 20-25%. Therefore, now, when designing, they are increasingly using their own renewable energy installations, at least to partially cover the needs. But this again increases the price.

Equipment and localization: where are we now?

Previously, key equipment - reformers, Syngas compressors, PSA systems - was actively purchased from Linde, Air Products, Topsoe. The current trend is towards complete localization. Chinese manufacturers have already reached a good level in the manufacture of synthesis gas columns, heat exchangers, and control systems. But there are still difficulties with catalysts and some special alloys for high-temperature zones.

Working withChengdu Yizhi Technology Co.(this is a design institute created by Huaxi Technology), observed their approach. They don’t just replicate ready-made solutions, but often adapt technology packages for the client’s specific raw materials. Their websiteyzkjhx.ruis, in fact, a portfolio of such non-standard projects. They have their own development - a multilayer catalyst for methane conversion with increased resistance to sulfur poisoning. Implemented at an installation in Sichuan. The results are not bad, but again, for ideal conditions. With sudden changes in load, activity fell faster than that of the imported analogue. There is progress, but we still have to work to reach full parity.

An interesting case is the use of ready-made modular installations of low and medium power. This is a trend for decentralized hydrogen production, for example for gas stations. Chinese companies, including Yizhi Technology, are very active here. Assembled, connected, launched. But the reliability of such “out of the box” solutions in harsh winters in northern China or high humidity in the south is a big question. Frequent maintenance stops and filter replacement. Reliability is still inferior to large stationary complexes.

Intermediates: the role of synthesis gas

What is often overlooked is that producing hydrogen is not always the end goal. Synthesis gas itself is a valuable raw material. In China, with its powerful chemical industry, this is critically important. Many projects are initially conceived as flexible production: today we maximize the yield of hydrogen for refineries, tomorrow we switch the mode for the production of methanol or ammonia.

I came across a situation where, due to changes in market conditions (hydrogen prices fell, methanol prices rose), the operating system had to be urgently changed. This was not just a setup, but a physical replacement of cartridges in the hydrogen fine purification system (PSA) and readjustment of the compressor system. The downtime was almost a month. Now, when designing new installations, much greater flexibility is built in, but this again means an increase in capital costs.

Another aspect is the purity of hydrogen. Fuel cells require the highest degree of purification (up to 99.999%). Achieving it using hydrocarbon raw materials is difficult and expensive. The main impurities - CO and CO2 - are poisons to the fuel cell catalyst. Standard adsorption methods do not always give the desired result. You have to combine: high-temperature conversion, then low-temperature conversion, then PSA, and sometimes also membrane separation. Each additional stage is a loss of pressure, energy and, of course, money. Therefore, “hydrogen for transport?” from methane cannot yet compete in price with the same hydrogen for oil refining, where purity requirements are lower.

Looking ahead: what will happen to this segment?

Despite all the hype around green hydrogen, the gray and blue lines of hydrocarbons will dominate China for a long time to come. The reasons are infrastructure, cost and, most importantly, the availability of raw materials. The question is how to make this process acceptable from an environmental point of view. I think the future lies not in any one breakthrough, but in a set of measures: the gradual introduction of CCS where it is geographically and economically justified; hybridization with renewable energy sources for power supply of installations; and continuous work on the efficiency of catalysts and thermal circuits to reduce raw material and energy consumption per unit of product.

Much will depend on carbon pricing policies. If the cost of CO2 emissions becomes significant, the economics of the projects will change dramatically. Now many decisions are made based on short-term economics, rather than long-term ecology.

Personally, I am skeptical about the imminent complete abandonment of hydrocarbon feedstock for hydrogen. Rather, we will see its niche. Large, modern, possibly hybrid (partially using biomethane) complexes near consumption centers or CO2 storage sites. And for remote or small consumers, electrolyzers powered by renewable energy sources will be developed. But the base - the chemical industry, oil refining - will remain based on technologies for the conversion of methane and its analogues for another 20-30 years. The main thing is not to hush up problems, but to work honestly on them, taking into account all costs, including environmental ones.