High-pressure methanol synthesis

The alkalized zinc oxide—chromia process developed by SEHT was tested on a commercial scale between 1982 and 1987 in a renovated high pressure methanol synthesis plant in Italy. This plant produced 15,000 t/yr of methanol containing approximately 30% higher alcohols. A demonstration plant for the lEP copper—cobalt oxide process was built in China with a capacity of 670 t/yr, but other higher alcohol synthesis processes have been tested only at bench or pilot-plant scale (23). 

Thermal chlorination of methane was first put on an industrial scale by Hoechst in Germany in 1923. At that time, high pressure methanol synthesis from hydrogen and carbon monoxide provided a new source of methanol for production of methyl chloride by reaction with hydrogen chloride. Prior to 1914 attempts were made to estabHsh an industrial process for methanol by hydrolysis of methyl chloride obtained by chlorinating methane. 

Schuth, F., High-throughput screening under demanding conditions Cu/ZnO catalysts in high pressure methanol synthesis as an example, J. Catal. 2003, 216, 110-119. 

Many studies of simultaneous adsorption of hydrogen or water and CO or C02 have been carried out on the high-pressure methanol synthesis catalysts based on zinc oxide and one or several other oxides, but only three investigations (104, 113, 114) dealt with catalysts containing copper, and two of these were made in reference to the mechanism of the low-temperature shift reaction. 

Then, the surface species were investigated under high-pressure methanol synthesis conditions by DRIFT spectroscopy. DRIFT spectra were recorded as a fimction of time when the sulfided Ca/Pd/SiO2 (Ca/Pd=0.5) was exposed to the stream of syngas at 613 K and S.l MPa (Figure 5 (a)). 

Example 11.9 m-1 Simulation of a Fauser-Montecatini Reactor for High-Pressure Methanol Synthesis... 

Tests with catalysts containing copper were carried out by Imperial Chemical Industries Ltd., England, from about 1958 to 1962 and eventually a practical copper catalyst for methanol synthesis and the first Low-pressure Methanol Processes were brought onto the market. In the process developed by ICI the quench reactor, in which the reaction heat is removed by quenching with cold gases and which is known from high-pressure methanol synthesis, is used. 

Following the introduction of a copper chromite catalyst based on the DuPont recipe for zinc chromite, a further copper catalyst was developed from experimental work related to the high-pressure methanol synthesis process." " ... 

The low-pressure acetic acid process was developed by Monsanto in the late 1960s and proved successful with commercialization of a plant producing 140 X 10 metric tons per year in 1970 at the Texas City (TX, USA) site [21]. The development of this technology occurred after the commercial implementation by BASF of the cobalt-catalyzed high-pressure methanol carbonylation process [22]. Both carbonylation processes were developed to utilize carbon monoxide and methanol as alternative raw materials, derived from synthesis gas, to compete with the ethylene-based acetaldehyde oxidation and saturated hydrocarbon oxidation processes (cf. Sections 2.4.1 and 2.8.1.1). Once the Monsanto process was commercialized, the cobalt-catalyzed process became noncom-... 

Catalysts based on CuO-ZnO are of great industrial interest because they exhibit high activity for the low temperature-pressure methanol synthesis and the water-gas-shift reactions. It is known that the activity and useful life of catalysts depend mainly on the activation process and the thermal history they experience during the operation. In the low temperature water gas shift (LTWGS) process, prior to reaction, the catalyst is activated by gas reduction to convert copper oxide into metallic copper [1]. It has been observed that reduction conditions affect the activity and the stability of Cu-ZnO catalysts. For instance, sintering and formation of alloys must be avoided in the reduction step because they deactivate the catalyst [2-3] for the water-gas-shift reaction. 

Derivation (1) By high-pressure catalytic synthesis from carbon monoxide and hydrogen (2) partial oxidation of natural gas hydrocarbons (3) several processes for making methanol by gasification of wood, peat, and lignite have been developed but have not yet proved out commercially (4) from methane with molybdenum catalyst (experimental). 

Table VII presents the estimated investments. The methanol case investment reflects the same gasifier type as used for the IBG and SNG cases. A conceptual Chem Systems methanol synthesis step is used. EPRI is sponsoring the development of the Chem Systems technology (5 ). The ammonia case investment reflects the same wood gasification concepts, employs pressure swing adsorption for hydrogen gas purification (based on information provided by the Linde Division, Union Carbide Corporation), and uses a conventional high-pressure ammonia synthesis loop.

Figure 3.19 Flow diagram of the Haldor Topsoe A/S low pressure methanol synthesis process. (1) desulfurizer, (2) process steam generation unit, (3) primary reformer, (4) oxygen-blown secondary reformer, (5) superheated high-pressure steam generator, (6) distillation section, (7) single-stage syngas compressor, (8) synthesis loop, and (9) is recirculator compressor for recycle gas. Source [9,14],...

High pressure technology transfer and diversification took many avenues, though most new innovations continued to appear from BASF. First, in 1923, was methanol production at the Leuna ammonia factory, and based on the work of Matthias Pier. BASF had patented a high pressure methanol process in 1914, but no further studies were carried out until after G. Patart in France applied for a similar patent (1921). In this case the same equipment could be used to manufacture ammonia or methanol, according to demand. Synthesis gas, the mixture of hydrogen and carbon monoxide, was used directly, without separation, to prepare methanol. In a similar way, isopropanol was manufactured under high pressures. 

In the traditional high pressure -or rather high temperature-methanol synthesis processes Zn-Cr-catalysts were used. These catalysts require temperatures in the range 330-410 C, and at these temperatures pressures above 300 bar are required to obtain reasonable equilibrium conversion even in stoichiometric CO/H mixtures with low CO concentration. 

Even though form amide was synthesized as early as 1863 by W. A. Hoffmann from ethyl formate [109-94-4] and ammonia, it only became accessible on a large scale, and thus iadustrially important, after development of high pressure production technology. In the 1990s, form amide is mainly manufactured either by direct synthesis from carbon monoxide and ammonia, or more importandy ia a two-stage process by reaction of methyl formate (from carbon monoxide and methanol) with ammonia. 

Because the synthesis reactions are exothermic with a net decrease in molar volume, equiUbrium conversions of the carbon oxides to methanol by reactions 1 and 2 are favored by high pressure and low temperature, as shown for the indicated reformed natural gas composition in Figure 1. The mechanism of methanol synthesis on the copper—zinc—alumina catalyst was elucidated as recentiy as 1990 (7). For a pure H2—CO mixture, carbon monoxide is adsorbed on the copper surface where it is hydrogenated to methanol. When CO2 is added to the reacting mixture, the copper surface becomes partially covered by adsorbed oxygen by the reaction C02 CO + O (ads). This results in a change in mechanism where CO reacts with the adsorbed oxygen to form CO2, which becomes the primary source of carbon for methanol. 

High pressure processes P > 150 atm) are catalyzed by copper chromite catalysts. The most widely used process, however, is the low pressure methanol process that is conducted at 503—523 K, 5—10 MPa (50—100 atm), space velocities of 20, 000-60,000 h , and H2-to-CO ratios of 3. The reaction is catalyzed by a copper—zinc oxide catalyst using promoters such as alumina (31,32). This catalyst is more easily poisoned than the older copper chromite catalysts and requites the use of sulfiir-free synthesis gas. 

Methanol Synthesis. Methanol has been manufactured on an industrial scale by the cataly2ed reaction of carbon monoxide and hydrogen since 1924. The high pressure processes, which utili2e 2inc oxide—chromium oxide catalysts, are operated above 20 MPa (200 atm) and temperatures of 300—400°C. The catalyst contains approximately 72 wt % 2inc oxide, 22 wt % chromium (II) oxide, 1 wt % carbon, and 0.1 wt % chromium (VI) the balance is materials lost on heating. 

The performance of many metal-ion catalysts can be enhanced by doping with cesium compounds. This is a result both of the low ionization potential of cesium and its abiUty to stabilize high oxidation states of transition-metal oxo anions (50). Catalyst doping is one of the principal commercial uses of cesium. Cesium is a more powerflil oxidant than potassium, which it can replace. The amount of replacement is often a matter of economic benefit. Cesium-doped catalysts are used for the production of styrene monomer from ethyl benzene at metal oxide contacts or from toluene and methanol as Cs-exchanged zeofltes ethylene oxide ammonoxidation, acrolein (methacrolein) acryflc acid (methacrylic acid) methyl methacrylate monomer methanol phthahc anhydride anthraquinone various olefins chlorinations in low pressure ammonia synthesis and in the conversion of SO2 to SO in sulfuric acid production. 

Higher molecular primary unbranched or low-branched alcohols are used not only for the synthesis of nonionic but also of anionic surfactants, like fatty alcohol sulfates or ether sulfates. These alcohols are produced by catalytic high-pressure hydrogenation of the methyl esters of fatty acids, obtained by a transesterification reaction of fats or fatty oils with methanol or by different procedures, like hydroformylation or the Alfol process, starting from petroleum chemical raw materials. 

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