Is China a leader in coke oven gas purification? 

When you hear such a headline, the first thought is another marketing ploy. The industry is full of myths: someone shouts about breakthrough technologies, but in reality they are slightly modernized old scrubbers. But if we put aside the hype and look at the actual volumes of implementation, especially at new coke-chemical complexes, the picture begins to become clearer. The point is not that China has invented something radically new, but the scale and speed of adaptation of technologies to specific, often very stringent, environmental standards. And here there is no time for beautiful presentations - there is daily work, where every failure costs millions.

From theory to "dirty" hands: evolution of approaches

Previously, about ten years ago, many, including us, thought that the task of cleaning was primarily a matter of choosing the right imported equipment. German, Japanese solutions... It seemed that I bought it and the problem was solved. Bitter disappointment came quickly: the samecoke oven gas, coming out of our coke ovens, the composition of impurities could be radically different from the European one. The raw materials are different, the carbonization modes are different. As a result, the expensive installation for removing naphthalene simply “suffocated”. per month, requiring unimaginable cleaning frequency.

This period of trial and error, in my opinion, became key. We had to move away from the role of simple integrators and start digging deeply into the chemistry of the processes. It’s not easy to “clean”, but to understand the chain: from the parameters of the charge and temperature in the furnace to the behavior of each fraction of resin and ammonia water at subsequent stages. It was then that the first serious design institutes appeared, focused specifically on this task. Here, for example,Chengdu Yizhi Technology Co.— their appearance in 2013 coincided with this turning point in the industry. This is not a random office, but a dedicated division with a solid authorized capital, which immediately hints at long-term and capital-intensive developments.

Their approach, like that of other market leaders, is no longer hardware based. It has become technological. That is, they do not sell a scrubber, but a guaranteed output result: the content of H2S, NH3, cyanide, benzene hydrocarbons. And how to achieve this - a combination of physical washing, chemical catalysis or biological treatment - is their headache. This is the very transition from purchasing hardware to implementing know-how, which creates leadership.

Specifics that you can’t read in a textbook

Let's take a seemingly routine step - the capture of tar and naphthalene. In theory, everything is simple: cool, condense. In practice it's a nightmare. The composition of this mixture is so variable that predicting the temperature at which naphthalene begins to crystallize is a difficult task. The heat exchangers get clogged - and that’s it, production stops. You have to resort to tricks, for example, introducing pre-washing systems. gas with recirculating oil with precise selection of its fractional composition. This is not according to GOST, it is developed through experience, often at a specific plant.

Or another nuance - the fight againsthydrogen sulfide. There are a lot of methods: from classic vacuum-carbonate to direct oxidation. Chinese engineers, in my opinion, have succeeded in adapting the so-called “flexible” ones. schemes Why? Because the customer often sets the condition: “I want to later have the opportunity to switch to the production of elemental sulfur if the market changes?” This means that your desulphurization plant must be built with the possibility of modernization without stopping for a year. Designing with such a foundation is already aerobatics.

It’s worth mentioning here a resource that is often overlooked -coke industryChina generates gigantic amounts of data. Each new complex consists of thousands of sensors. Analysis of this big data allows you to fine-tune modes, predict catalyst wear, and optimize reagent consumption. Empirics backed by statistics gives a huge advantage. On their websiteyzkjhx.ruit is clear that the emphasis is on complex “turnkey” solutions, which implies deep analytics at the design stage.

Not only successes: the cost of mistakes and dead-end branches

It would be dishonest to talk only about victories. The race for efficiency also created blind alleys. I remember a story at one of the factories in Shanxi, where they decided to use a super-active imported hydrogenation catalyst to remove organic sulfur compounds. The technology is cool, but the catalyst turned out to be wildly sensitive to the slightest traces of oxygen and mechanical impurities. And to guarantee perfect pre-cleaning on worn-out Soviet equipment from the 70s... In general, an expensive load turned into useless powder in three weeks. The project was scrapped and we returned to cruder but more reliable methods. It was a lesson worth millions of yuan: the most advanced technology is useless unless it is integrated into an existing, less-than-ideal technology cycle.

Another sore subject is the disposal of purification by-products, such as thiocyanate pulp or sludge. It is possible to make clean gas, but then storing this waste in a landfill for years is not a solution. Now the vector has shifted to creating waste-free cycles, where waste from one stage becomes raw material for another. But this is the ideal. In reality, you often come up against economics: processing the same thiocyanate into a commercial product is unprofitable at current prices. And here you sit, looking for a compromise between environmental regulations and commercial feasibility.

It is in such dead ends that truly interesting solutions are born. For example, joint disposal of gas purification waste with other enterprise streams (for example, wastewater) in a single installation. This requires incredibly complex interdisciplinary design, but it kills several birds with one stone. A highly specialized Western contractor often refuses such “hybrid” ones. problems, and local institutions, like the aforementioned Yizhi Technology, are forced to solve them - there is simply no other way out.

The role of local players and import substitution

Five to seven years ago, key equipment - compressors, high-precision valves, automation systems - was still purchased in Europe or Japan. Now the situation is changing. The pressure of sanctions and the policy of “dual circulation” stimulated the development of their own mechanical engineering. And what is important, the designers began to work closely with these manufacturing plants “from scratch”, explaining exactly what parameters are critical for working withcoke oven gas: resistance to deposition of ammonium salts, specific requirements for explosion protection, resistance to cyclic temperature loads.

This synergy pays off. A domestic pump for pumping ammonia water with a special coating may turn out to be one and a half times cheaper than its German counterpart and at the same time last longer in these specific conditions, because it was originally designed for them. The design institute acts as a connecting link here, translating practical operating experience into technical specifications for machine builders. Their websiteyzkjhx.ruin essence, it is a showcase of just such an integrated approach, where they position themselves not as sellers, but as partners in solving technological problems.

As a result, we have a situation where the full cycle - from fundamental research in the field of coking chemistry to the manufacture of a specific valve - can be closed within one country. This doesn't mean everything is perfect, but it does result in incredible iteration speed and lower cost of ownership. Western companies often lose not in the quality of hardware, but in flexibility and speed of response to customer problems.

So is he a leader or not? View from the workshop

Returning to the title. If we talk about theoretical breakthroughs or the creation of fundamentally new cleaning methods, perhaps not. Fundamental discoveries still often come from other countries. But if we evaluate leadership as the ability to solve real, large-scale and “dirty” decisions. industrial tasks efficiently and in a short time - the answer is most likely yes.

Leadership here is not a gold medal, but a daily routine. This is when you can come to a plant where gas analysis shows wild jumps, and after a couple of days, having tinkered with the settings and adding a pre-washing step, bring the process to a stable mode. This is knowledge that is not in the installation passport, but in the engineer’s notebook. These are thousands of working installations, each of which is a unique case.

Therefore, looking at the new giant coke-chemical complexes that are being built from scratch? with such indicators of gas purity that many European plants have never dreamed of, you understand that enormous practical experience has been accumulated here. And companies that have gone this way from blind copying to creating adaptive, integrated solutions are precisely the bearers of thisleadership. This leadership is not about loud statements, but about the ability to make everything work day after day, in conditions far from laboratory ones. And in this sense, yes, there is a lot to learn.