Maleic Anhydride (MAN)
The SD process produces MAN from n-butane at very high yields using a patented "Series Reactor" design and a continuous recovery system for the production of excellent quality product. Description: The concept of series reactor design allows the oxygen rich effluent air from the first reactor/recovery system to be fed to the second reactor operating in series. Thus, the air flow requirement is reduced to half. The unconverted butane from the first reactor, supplemented with fresh n-butane to make up the required concentration feeding the second reactor, also gets a second chance to convert to MAN and thereby a 10+ point improvement in the overall yield. The continuous recovery and refining system produces MAN in the form of very high quality molten product. N-butane and air are fed to the first fixed-bed reactor (1) to produce maleic anhydride. After heat removal, MAN is fully recovered in an absorber system (2). The effluent gas is mixed with makeup n-butane and fed to the second fixed-bed reactor (3) to produce more maleic anhydride. Once again, after heat removal, MAN is fully recovered in a second absorber system (4). This results in 50% reduction in air demand and a very significant reduction in power consumption. The overall butane conversion is increased resulting in a large increase in the overall yield of MAN. The effluent gas is incinerated to meet environmental emission standards and to recover heat value in the form of high pressure steam (5). Pure MAN is produced in a fully continuous recovery refining system (6). The expected recovery yield is 99%. Yields: The yield of MAN (kg per kg N-butane feed) is in the range of 108 weight % at the start-of-run (SOR). Commercial Plants: The series reactor design, which is a small deviation from the standard fixed bed design, has been successfully pilot tested for a continuous operation of over 6 months. It is ready for commercialization. The promise to offer (a) an overall high butane concentration, the likes of a fluid-bed process but without compromising the safety, and (b) high selectivity of a fixed bed system in one unique design has generated tremendous interest in the industry. Additional Information:
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