Comparison between NHD devolatilization operation and tannin vanadium

In situations with large scale and high pressure for conversion, if the sulfide concentration is high (without prior gas desulfurization), using the tannin method for desulfurization results in significant losses of carbon dioxide (including hydrogen), and complete desulfurization cannot be achieved even in a single stage; moreover, the cost of multiple stages of desulfurization is relatively high. Therefore, the tannin method is not used in such cases, and instead low-temperature methanol washing or NHD is employed for desulfurization (and decarburization). NHD desulfurization requires a certain scale, mainly to ensure that the regenerated acid gas (sulfides) can be recovered using the Claus process. Some manufacturers burn this regenerated gas in boilers, which is obviously not feasible. The purification unit associated with Huaihua’s 200,000-ton Texaco gasification plant uses this process; when the concentration cannot be brought up to the desired level, the acid gas recovery system (low-concentration Claus process) cannot be put into use for a long time. At a larger scale, low-temperature methanol washing is used. The reason why there are so few NHD desulfurization manufacturers at home and abroad is self-evident. The preliminary conclusion is that NHD desulfurization incurs much higher investment and costs compared to tannin-based desulfurization. (The benchmark is the condition where charring can occur.) ）