High-pressure Hastelloy reactor

In the BASF process, methanol and CO are converted in the liquid phase by a homogeneous Co-based catalyst. The reaction takes place in a high-pressure Hastelloy reactor. In recent decades the BASF process has been increasingly replaced by low-pressure alternatives mainly due to lower investment and operating costs. In the low-pressure Monsanto process methanol and CO react continuously in liquid phase in the presence of a Rhl2 catalyst. In 1996, BP developed a new attractive catalyst based on iridium (Cativa process) the oxidative addition of methyl iodide to iridium is 150-times faster than to rhodium. The search for acetic acid production processes with even lower raw material costs has led to attempts to produce acetic acid by ethane oxidation. In the near future ethane oxidation will most likely not compete with methanol carbonylation (even though ethane is a very cheap and attractive raw material) because of the low ethane conversions, product inhibition problems, and a large variety of by-products. 

The heart of the system is the oxidation vessel depicted in Figure 1. This vessel is a high pressure, 1000 cc, Hastelloy C-276, bolted closure reactor manufactured by Autoclave Engineers Inc. Hastelloy C-276 was chosen as the material of construction due to its excellent corrosion resistance to a wide variety of chemical process environments, which include processes utilizing strong oxidizers (5,6,7). The unit is fitted with 1/8" and 1/4" Hastelloy C-276 feed delivery and product outlet lines... 

This process operates in the aqueous phase at 250 C and 65.10 Pa absolute, in the presence of cobalt iodide as catalyst The high-pressure reactor lined with hastelloy C for corrosion resistance features internal agitation of the liquid obtained by gas injection ( air lift type). It is continuously supplied with a stream of methanol, dimethyl ether, carbon monoxide if required, and water preheated to between 40 and 80°C. The amount of water added is one-third of that of methanol by weight The arid mixture and the unreacted gases are collected at the top of the reaction tower, cooled, and brought to 1.10 Pa absolute in a flash drum. The methyl iodide and header components in, the Hashed gases are recovered by scrubbing with methanol feed. ... 

High pressure reactor with hastelloy vessel... 

The activity tests of the catalyst were carried out in a microflow reactor set-up in which all the high temperature parts are constructed of hastelloy-C and monel. The reactor effluent was analyzed by an on-line gas chromatograph with an Ultimetal Q column (75 m x 0.53 mm), a flame ionization detector, and a thermal conductivity detector. The composition of the feed to the reactor can be varied, besides the temperature, pressure, and space velocity. The influence of the recycle components CHCIF2 and methane was tested by adding these components to the feed. In total five stability experiments of over 1600 hours were performed. In each... 

Hastelloy X (HastX) is a nickel-based superalloy used in a variety of applications [Brown, 1992]. Its composition is 49% nickel, 22% chromium, 18% iron, 9% molybdenum, 1.5% cobalt and 0.5% tungsten. The melting point of HastX is about 1530 K, and it has a density of 8.22 g/cc. This material has been suggested as a possible reactor material for a variety of reasons. HastX is a material with decent high temperature characteristics. Hastelloy is also noted for excellent corrosion, oxidation and carburization resistance at the desired temperatures. Finally, Hastelloy-X is a commonly used metal whose properties are well understood. The expected peak temperature of Hastelloy-X is roughly 875 K when used for the pressure vessel of the reactor. 

The Monsanto process and the hi er pressure BASF processes have been reviewed [3,1012]. In the Monsanto process (Fig. 1) [9], methanol and carbon monoxide are fed to a continuous reactor system. The corrosive nature of iodine in an acid medium requires the use of a highly corrosion-resistant metal reactor (made of such material as Hastelloy C). The acetic acid produced is piuified by conventional distillation. The purified acetic acid is sent to a drying column. The dried acetic acid is removed as the bottom product and sent to the product column to reduce the small concentration of propanoic acid. The typical composition of the acetic acid from this process is [9] as follows ... 

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