Synthesis gas, ammonia and methanol

The production of mixtures of carbon monoxide and hydrogen from coal or coke was the basis for town gas manufacture from well before the turn of the century, and the processes were adapted to provide appropriate feeds for ammonia and methanol synthesis in Germany and elsewhere. 

Low prices for natural gas in the U.S. and naphtha in Europe prompted a change in feedstock. In the U.K., town gas was also produced by the steam reforming of naphtha, which provided about 90% of supplies in 1968, but was totally displaced by the newly found natural gas during the 1970s. European production of synthesis gas for chemical processing is now almost solely based on steam reforming of natural gas. 

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Figure 5-1. Important chemicals based on methane, synthesis gas, ammonia, and methanol. ...

There are different tubular and column plug flow reactors as well as screw reactors [1]. Plug flow reactors are used for various gas-phase reactions occuring within industrial-scale production, particularly for the reactions of nitrogen oxide oxidation, ethylene chloration, and high-pressure ethylene polymerisation. They are also used for some liquid-phase and gas-liquid reactions, e.g., styrene polymer production in a column, plastic and rubber production, synthesis of ammonia and methanol, and sulfation of olefins [2]. 

Oxygen enrichment of steel blast furnaces accounts for the greatest use of the gas. Large quantities are also used in making synthesis gas for ammonia and methanol, ethylene oxide, and for oxy-acetylene welding. 

The Texaco process was first utilized for the production of ammonia synthesis gas from natural gas and oxygen. It was later (1957) appHed to the partial oxidation of heavy fuel oils. This appHcation has had the widest use because it has made possible the production of ammonia and methanol synthesis gases, as well as pure hydrogen, at locations where the lighter hydrocarbons have been unavailable or expensive such as in Maine, Puerto Rico, Brazil, Norway, and Japan. 

Direct hydrogen cyanide (HCN) gas in a fuel oil gasification plant to a combustion unit to prevent its release. 4. Consider using purge gases from the synthesis process to fire the reformer strip condensates to reduce ammonia and methanol. 5. Use carbon dioxide removal processes that do not release toxics to the environment. When monoethanolamine (MEA) or other processes, such as hot potassium carbonate, are used in carbon dioxide removal, proper operation and maintenance procedures should be followed to minimize releases to the environment. 

As mentioned in Chapter 2, methane is a one-carhon paraffinic hydrocarbon that is not very reactive under normal conditions. Only a few chemicals can he produced directly from methane under relatively severe conditions. Chlorination of methane is only possible by thermal or photochemical initiation. Methane can be partially oxidized with a limited amount of oxygen or in presence of steam to a synthesis gas mixture. Many chemicals can be produced from methane via the more reactive synthesis gas mixture. Synthesis gas is the precursor for two major chemicals, ammonia and methanol. Both compounds are the hosts for many important petrochemical products. Figure 5-1 shows the important chemicals based on methane, synthesis gas, methanol, and ammonia. ... 

The two major chemicals based on synthesis gas are ammonia and methanol. Each compound is a precursor for many other chemicals. From ammonia, urea, nitric acid, hydrazine, acrylonitrile, methylamines and many other minor chemicals are produced (see Figure 5-1). Each of these chemicals is also a precursor of more chemicals. 

Synthesis gas, the third important intermediate for petrochemicals, is generated hy steam reforming of either natural gas or crude oil fractions. Synthesis gas is the precursor of two hig-volume chemicals, ammonia and methanol. 

The shift reaction can be conducted in a second reactor, catalyzed by a mixture of iron and chromium oxides. The product of reforming is known as synthesis gas, or syngas, and is mostly used in the manufacture of ammonia and methanol. One of the earliest steam reforming processes was developed in Germany by I.G. Farbenindustrie in 1926. See also catalytic reforming. 

The next 10 chapters cover a collection of petrochemicals not altogether related to each other. Synthesis gas is a basic building block that leads to the manufacture of ammonia and methanol. MTBE is made from methanol from synthesis gas (with a little isobutylene thrown in). The alcohols in Chapter 14 and 15, the aldehydes in 16, the ketones in 17, and the acids in 18 are all closely related to each other by looks, though the routes to get to them are perplexingly different. Alpha olefins and the plasticizer and detergent alcohols have the same roots and routes, but different ones from the rest. Maleic anhydride, acrylonitrile, and the acrylates— well, they re all used to make polymers and they had to be somewhere. 

Synthesis gas is a loose name for hydrogen/carbon monoxide mixtures of varying proportions. These two compounds are so basic, they are too simple to start with for most petrochemicals. The primary applications of synthesis gas are only ammonia and methanol manufacture and a little normal butyl and 2-ethylhexyl alcohol production. 

ATR is a stand-alone process which combines POX and SR in a single reactor. The ATR process was first developed in the late 1950s by Topsoe, mainly for industrial synthesis gas production in ammonia and methanol plants [27]. 

In Germany, before and during the Second World War, a large amount of ethylene was produced from acetylene derived from coke oven gas. Coke ovens also provided essentially all the aromatics in Germany. Coal was also gasified, giving synthesis gas, a mixture of CO and H2. Products such as ammonia and methanol were catalytically produced from this synthesis gas. Fischer-Tropsch technology was also developed to convert synthesis gas to motor fuels. 

The Rectisol process is very flexible and can be configured to address the separation of synthesis gas into various components, depending on the final products that are desired from the gas. It is very suitable to complex schemes where a combination of products is needed, for example, hydrogen, carbon monoxide, ammonia and methanol synthesis gases, and fuel gas sidestreams. 

The tubular reactor is a relatively common component on chemical plants. The reactants enter at one end and the products leave from the other, with a continuous variation in the composition and the temperature of the reacting mixture in between. It is common for the feed to consist of a mixture of gases, as in the case of ammonia and methanol synthesis, where the feed gas passes through a densely packed catalyst bed which promotes a number of different reactions simultaneously. 

The effect of various operating conditions on the recovery of the pulping chemicals and heat values in the case of a neutral sulfite semichemical (NSSC) spent liquor has been described recently (I). The thermodynamic equilibria and kinetics of gasification which seem to apply to this same set of experiments were discussed elsewhere (9). Gas compositions and yields examined in the latter study showed that under some of the operating conditions investigated, commercially significant quantities of ammonia and methanol synthesis gases could be produced from NSSC-type spent liquors. 

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