ICI low-pressure process

Figure 5-5. The ICI low-pressure process for producing methanol " (1) desulfurization, (2) saturator (for producing process steam), (3) synthesis loop circulator, (4) reactor, (5) heat exchanger and separator, (6) column for light ends recovery, (7) column for water removal.

Two versions of the MTG process, one using a fixed bed, the other a fluid bed, have been developed. The fixed-bed process was selected for installation in the New Zealand gas-to-gasoline (GTG) complex, situated on the North Island between the villages of Waitara and Motonui on the Tasman seacoast (60). A simplified block flow diagram of the complex is shown in Figure 6 (61). The plant processes over 3.7 x 106 m3/d(130 x 106 SCF/d) of gas from the offshore Maui field supplemented by gas from the Kapuni field, first to methanol, and thence to 2.3 x 103 m3/d (14,500 bbl/d) of gasoline. Methanol feed to the MTG section is synthesized using the ICI low pressure process (62) in two trains, each with a capacity of 2200 t/d. 

Fig. 22.3. Manufacture Of chemical or fuel-grade methanol from hydrocarbon feedstocks using ICI low-pressure process. (Hydrocarbon Processing, p. 144, Nov. 1986. Copyright 1985 by Guff Publishing Company and ussa by parmission of the copyright owner.)...

ICI Low Pressure Methanol A process for making methanol from methane and steam. The methanol is first converted to syngas by steam reforming at a relatively low pressure. The syngas is then converted to methanol over a copper-based catalyst ... 

LCM [Leading Concept for Methanol] A process for making methanol, combining the ICI Low Pressure Methanol process with the steam reforming section of the LCA ammonia process. Developed by ICI in 1990 and piloted in Melbourne, Australia, from 1994. Envisaged for floating factories in off-shore gas fields. 

Naphtha was the initial feedstock for the ICI low pressure methanol process because it was available to ICI at the time they developed the process. However, it is also the most ideal feedstock from a stoichiometric viewpoint as evidenced by the following reaction. 

Most modern processes are low pressure processes. Plant capacities range from 150-3000 tons/day. The plants differ mainly in reactor design and, interrelated with this, in the way the heat produced by the reaction is removed. In the ICI process an adiabatic reactor is used with a single catalyst bed. The reaction is quenched by adding cold reactant gas at different heights in the catalyst bed. The temperature profile in the bed has a sawtooth profile. A flow scheme of the ICI process is given in Fig. 2.20. 

Schiller A predecessor of the ICI Low Pressure Methanol process, developed by IG Farben. 

Anonymous, The ICI Low Pressure Methanol Process, Agricultural Division, Imperial Chemical Industries, Bilingham, England, No date. 

In 1963, Imperial Chemical Industries (ICI) PLC announced an innovative process using Cu/Zn0/Al203 catalysts, later called low-pressure synthesis. The major constituents of this catalytic system are Cu (reduced form of CuO) and ZnO on an A1203 support. The reaction pressure and temperature are 220-270 °C and 5-10MPa, respectively. The catalysts have been found to be susceptible to sulfur and carbonyl poisoning, sintering, and thermal aging. Nowadays, almost all of commercial methanol syntheses are carried out by low-pressure processes. 

Barriers to entry into the pseudocommodity business include all the barriers for commodities plus the all-important customer know-how. Lack of technical expertise and patent protection can be formidable barriers to potential producers of a pseudocommodity. Du Pont was the sole producer of nylon from 1939 to 1951. Barriers to entry were removed under threat of government antitrust action in 1951, with the licensing of Chemstrand, which later became part of Monsanto. Since then a number of companies have entered the nylon business. Technical know-how and patent protection played a major role in both high- and low-pressure polyethylene manufacture in the years shortly after World War II. ICI developed polyethylene, but Union Carbide had a superior high-pressure process. Ziegler, Du Pont, and Phillips Petroleum all developed low-pressure processes, which they subsequently licensed to other manufacturers. Many pseudocommodities eventually become commodities by the diffusion of technology, standardization of the product, and the entry of many firms into the business. 

The GTM plant employs the ICI low-pressure Methanol Process sub-licensed from Davy McKee, and incorporates two methanol trains each capable of producing 2200 tonnes per day of methanol. 

The processing area of the plant consists of three process units two methanol plants and the methanol to gasoline (MTG) conversion plant. The methanol units convert natural gas from the Maui Platform to crude methanol using the ICI low pressure synthesis process. Each methanol plant can produce 2200 tonnes of methanol per day. The methanol is fed directly to the MTG unit where it is catalytically converted to gasoline and small amounts of LPG. 

A block flow diagram for production of fuel grade methanol from biomass is depicted in Figure I. The gasification step is based upon the Purox process and is followed by shift conversion and gas purification steps. The clean gas, which is shifted to a H2/CO ratio of approximately 2/1, is converted to methanol in the ICI low-pressure methanol synthesis process. The process yields approximately 98% pure methanol with the remaining 2% consisting of water and some higher carbon number alcohols. 

The high-pressure process, which used to be exclusively operated, is carried out with Zn0/Cr203 catalyst at 250-350 bar and 350 00°C. The development of more active, copper-based catalysts allowed the process to be carried out in the pressure range 50-100 bar and at lower temperatures. This improved the economics of the process. The low-pressure processes were developed by ICI and Lurgi and introduced in the mid-1960s. 

The familiar polymers polyvinyl chloride (PVC), polystyrene (PS), and polymethylmethacrylate (PMMA), which were produced in the 1930s and 1940s in large-scale production plants, are examples of so-called radical chain polymerization. One way of replacing the high-pressure polymerization method used for ethylene (ICI), which involved radical catalysts, with a low-pressure process, was provided by anionic coordinative catalysts, for example titanium tetrachloride plus aluminum triethyl as a cocatalyst in the method according to K. Ziegler (1953). 

Methanol is manufactured from syn. gas by passing the latter at 230-270°C/50-100atm over a copper oxide catalyst (CuO.ZnO or CuO.ZnO.Al Oj) (ICI Low Pressure Methanol process). (The copper oxide is reduced to metal.)... 

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