China: Ionic desulfurizer on the market? 

When they talk about Chinese equipment for gas purification, many still mentally see cheap copies or devices “for one season?”. But with ionic desulfurizers, the story seems to have taken a different path - it’s not so much about price, but about whether the technology can catch on in real, complex conditions, and not just in presentations.

Where does this interest in ion technologies come from?

It all started with tightening emission standards, especially SO2. Traditional wet scrubbers are, of course, a classic, but for many small and medium-sized enterprises their operation turns into a story of high operating costs and constant fuss with reagents and waste. This is where the request arose for something more “closed”, where there is no need to constantly purchase tons of limestone or ammonia.

The ion desulfurizer, roughly speaking, works on the principle of low-temperature plasma. The polluted gas passes through a zone where, under the influence of an electrical discharge, active particles (the same ions and radicals) oxidize SO2 to SO3, which is then easily combined with water into sulfuric acid or with ammonia into ammonium sulfate. It sounds elegant, but that's the rub - elegant in theory. In practice, the key issue has always been and remains the reliability of the electrodes and power supply in conditions of constant work with dusty and sometimes wet flows.

I remember about five years ago the first samples from some Chinese manufacturers failed precisely for this reason - the plasma-forming unit could not withstand prolonged load, breakdowns began, and efficiency dropped. Then many people branded the technology as “crude”. But since then the water has flown under the bridge, and approaches have clearly changed.

What has changed in practice? Chengdu Yizhi Technology Experience

Here, for example,Chengdu Yizhi Technology Co.— their design institute is already more than ten years old, and they are from the category who do not work in haste. The registered capital of 120 million yuan is not about garage production. They don't just sell a box with the name "ionic desulfurizer", but they promote complete solutions, which, in my opinion, is the only right way for such technology.

Their approach is often built around pre-adaptation. That is, before offering a specific model, they can study the composition of your particular gas for quite some time - not only SO2, but also dust, humidity, and the presence of other impurities such as volatile organic compounds. This is critically important, because the same dust can “jam” plasma discharge or sintering on the electrodes. On their websiteyzkjhx.ruit is clear that they focus specifically on engineering, and not on the standard catalogue. This already hints at a deeper dive.

From conversations with colleagues, I know that they implemented their system at one of the cement plants in Sichuan. There was just a problem with high dust levels and fluctuations in SO2 concentration. According to reviews, the key was not the plasma core itself, but the gas pre-cleaning and cooling system, whichChengdu Yizhiindividually designed. Without this "buffer" any ionic desulfurizer would quickly stall. This is the very practical nuance that separates a working solution from a laboratory prototype.

Where does technology really work and where does it fail?

Now the most successful cases of ion desulfurizer in China are, oddly enough, not always huge thermal power plants. More often these are industrial boilers of medium power, roasting areas in metallurgy or, as in the example above, the cement industry. Where the gas flow is more or less stable in volume and temperature, and where it is possible to install a high-quality gas treatment system in front of the main apparatus.

But, as far as I know, there were problems with waste gases from waste incineration plants. The composition was too unstable, high corrosiveness, and frequent temperature fluctuations “finished off” sensitive electronics. One engineer I know complained that they actually had to completely redo the control system and install additional purification stages after the plasma reactor in order to catch what was not completely oxidized. As a result, the savings on reagents were partially eaten up by the cost of this modification and repairs.

Therefore, a rather sober view has now formed in the industry: an ion desulfurizer is not a “universal killer?” scrubbers. This is a specific tool for specific conditions. Its main advantage is the absence of constant costs for alkali and less liquid waste. But its Achilles’ heel is its demands on the purity and stability of the inlet gas flow and, so far, a higher (albeit decreasing) capital cost compared to a simple scrubber.

About components and pitfalls?

If you dig into the device, then in addition to the plasma generation unit that everyone is discussing, there are a lot of important little things. For example, the material of the electrodes. Previously, many used relatively simple alloys, which quickly corroded in an environment with residual chlorine or fluorine. Currently leading players, includingChengdu Yizhi Technology, switch to special coatings or composite materials. The service life is promised to be up to 5-8 years, but only time will tell the real data.

Another point is the ammonia supply system (if the ammonium sulfate process is used). This requires pinpoint precision in dosing. Too little - all the SO3 will not react, there will be a breakthrough. Too much is not only an overconsumption of the reagent, but also the risk of forming ammonia emissions at the outlet. I saw an installation where this problem was solved using multi-point injection and a fast feedback system based on data from output analyzers. It works, but again it complicates and increases the cost of the system.

And, of course, “brains”. The control program must not simply turn the discharge on and off. It must adapt power to changing loads in real time, monitor the condition of the electrodes, and predict the need for maintenance. This software part is often the weakest point of less experienced manufacturers. The good news is that Chinese companies are now actively investing in exactly this, hiring automation and data scientists.

Market and prospects: is there a future here?

The market is certainly growing, but not at an explosive pace, but rather at a steady pace. This is good because it means a gradual accumulation of experience, and not a rush that will then burst, leaving behind a mountain of non-functioning equipment. The main customers now are enterprises that have already completed the first round of modernization with the installation of simple scrubbers and are now looking for ways to reduce operating costs and get rid of problems with sludge disposal.

It's interesting to see how sellers' rhetoric changes. Previously, the emphasis was on “revolutionary technology”. Now in materials, for example, fromChengdu Yizhi Technology Co., Ltd., formulations about “hybrid solutions” are increasingly encountered. and “integration into existing technological chains”. This is a sign of maturity. They understand that their apparatus is often not the first, but the second or third stage of purification in the overall gas purification scheme of the plant.

Forecast? The technology will remain niche. It is unlikely that it will displace wet methods from large facilities such as coal-fired power units, where the scale and sophistication of processes play a key role. But for the medium and small industry sector, especially where there is a shortage of water or difficulties with the logistics of reagents, an ion desulfurizer from China can become a very valid option. Under one condition - if the supplier, like Chengdu Yizhi, is ready not just to sell the unit, but to take responsibility for its integration into your specific process and for its long-term operation. Without this, everything will remain just a beautiful picture from an exhibition.