Published November 2012
Methanol carbonylation dominates the current era of acetic acid production, specifically the low water technologies using homogeneous catalysis, such as BP and Celanese. Celanese and BP dominate worldwide production, with Celanese being the main producer in the Americas and BP in Europe. The two companies seem to be dividing up Asia, with Celanese in China and Singapore, and BP in Korea, Malaysia, and Taiwan, although BP sites appear to be mainly joint ventures [CEH602.5000, CMAI120418, CMAI2011WAA]. The largest growth in acetic acid volume, however, stems from Chinese companies adding capacity to satisfy the growing Chinese demand.
Another concept, represented by the efforts of Chiyoda uses a heterogeneous catalyst. This review explores the effects of new technology and economy of scale on the Chiyoda process, since this process was last evaluated over a decade ago. World scale capacity at that time was 400 thousand metric tons per year (kta), and both BP and Celanese technologies were evaluated at that level [PEP037C]. Chiyoda technology was previously evaluated separately assuming a capacity of 363 kta, or 800 million pounds per year [PEP97-12]. Since then, world scale has risen to a maximum capacity of 650 kta [CEH602.5000, CMAI120418, CMAI2011WAA] established by Celanese in Singapore, in addition to a couple of 600 kta plants in China by both Celanese and Jiangsu Sopo.
Celanese appears to be targeting the 600 kta range, while BP seems focused on 500 kta. Both are adding incremental improvements, but Celanese seems to be setting the new world scale. Therefore, this review updates the Chiyoda technology to a 600 kta capacity, and includes recent technology developments illustrated in new patents and applications. The basis for the technology improvements stems from adding styrene and/or ethylbenzene to the polyvinylpyridine polymer support for the rhodium catalyst [US20120010371, WO2011099264]. Acidic cation exchange resins are also shown to improve the reaction. Even strong acids, added to the liquid flow, offer similar benefit, although at the expense of added separations. The benefit claimed is the accelerated hydrolysis of methyl acetate to improve reaction rates.