Requirements for metal-sealed ball valves in coal gasification units

Black water ball valves, as well as valves used for slag and ash containment, are difficult to manufacture domestically. Even imported versions do not last very long. Coal gasification plants generate a lot of dust, and solid particles have a significant impact on the sealing surfaces of these valves, leading to easy damage. I’ve seen imported valves used in a coal gasification project in Shanghai that cost over 500,000 yuan each; four such valves were purchased at once, and on average, none of them lasted more than three months before becoming unusable. Last edited by xuqinger on 2009-2-18 16:49

Wear-resistant metal ball valves feature hardened sealing surfaces, as well as dust-proof designs for the valve stem and spring chambers. Many manufacturers in China claim to be able to use the HVOF process, but it seems that the quality of these valves is still not up to standard. I heard recently about an American brand called KINDER – do you know it? Could it be a fake product? Its price is much lower than that of ARGUS and NELES

In response to the original poster’s question, based on my experience, in gasification units, the investment in oxygen valves, slag valves, and lockhopper valves is indeed substantial. So far, no domestic oxygen valves have been used in such devices; we are working on developing them, but it’s quite challenging and requires significant investment (**with very high requirements regarding qualifications**). For slag valves and lockhopper valves, imported ball valves are still the most common choice. The best-performing valves available currently have a service life of around 1 year. There are two domestic companies that attempt to replicate foreign ball valves, but their products have a much shorter lifespan and inferior quality. Our current approach is to use a special structure for disc valves, which theoretically allows for a service life 3–4 times longer than that of imported ball valves, in terms of both cost and durability. Unfortunately, we yet to have any practical results to prove this. Although we have achieved success in applications related to silicon chemistry and the crude synthesis of gas in coal chemical processing, with good feedback, and we have also completed tests using coal powder and coal slag, what’s still lacking are actual practical results.

Foreign-made valves are really good! The domestic manufacturing level simply cannot keep up, and moreover, people in this country focus on economic benefits; they pay little attention to investment in long-term research and development, having a rather short-term perspective! However, the efforts put into valves in China over the past few years have been quite good! There are some that I think can still be applied; we are using one of them, and it’s working fairly well for now, but its performance remains to be seen!