Hydrocarbon gases, origin

The oxidation of aromatic hydrocarbons originating from coal is one of the first organic gas phase oxidation processes carried out on an industrial scale. The development of these processes was initiated by the discovery that the V2Os catalyst used for the oxidation of sulphur dioxide was also applicable to the partial oxidation of benzene to maleic anhydride and naphthalene to phthalic anhydride. Remarkably, V2Os-based catalysts are still used in these processes today as they appear superior to any other type of catalyst. 

The inferiority of catalytically cracked gas oils, compared to virgin gas oils, as feed stocks (51) is attributable to higher concentrations of condensed-ring aromatics (95). The more-readily cracked hydrocarbons have already been converted, leaving behind the more-refractory hydrocarbons originally present in the fresh feed. In addition, some polycyclic hydrocarbons have been formed by the cracking operation. The polycyclic condensed-ring aromatics are not only difficult to crack but are also characterized by production of excessive yields of coke (79,345). 

Chlorine Chlorine gas produced in the various electrochemical processes is saturated with water vapor at high temperatures and may also contain brine mist and traces of chlorinated hydrocarbons (originating from piping and rubber-lined vessels), and is normally at atmospheric pressure. Before the chlorine can be used it must (in this order) be cooled, purified, dried, compressed, and if necessary liquefied. 

Sgc - hydrocarbon gas content as a percentage of the volume of the total pore space this gas is expressed in terms of gas equivalent original crude oil Sos - initial oil saturation (expressed as a fraction of 1)... 

Miscellaneous Sources. Additional sources consist of hydrocarbons in the naphtha range produced as condensates from natural gas processing and synthetically produced hydrocarbons originating from processes such as the Fischer-Tropsch process. 

The original method for the manufacture of ethyne, the action of water on calcium carbide, is still of very great importance, but newer methods include the pyrolysis of the lower paraffins in the presence of steam, the partial oxidation of natural gas (methane) and the cracking of hydrocarbons in an electric arc. 

When gases that are somewhat soluble in a Hquid concentrate are used, both concentrate and dissolved gas are expeUed. The dissolved gas then tends to escape into the atmosphere, dispersing the Hquid into fine particles. The pressure within the container decreases as the product is dispersed because the volume occupied by the gas increases. Some of the gas then comes out of solution, partially restoring the original pressure. This type of soluble compressed gas system has been used for whipped creams and toppings and is ideal for use with antistick cooking oil sprays. It is also used for household and cosmetic products either where hydrocarbon propeUants cannot be used or where hydrocarbons are undesirable. 

SASOL. SASOL, South Africa, has constmcted a plant to recover 50,000 tons each of 1-pentene and 1-hexene by extractive distillation from Fischer-Tropsch hydrocarbons produced from coal-based synthesis gas. The company is marketing both products primarily as comonomers for LLDPE and HDPE (see Olefin polymers). Although there is still no developed market for 1-pentene in the mid-1990s, the 1-hexene market is well estabhshed. The Fischer-Tropsch technology produces a geometric carbon-number distribution of various odd and even, linear, branched, and alpha and internal olefins however, with additional investment, other odd and even carbon numbers can also be recovered. The Fischer-Tropsch plants were originally constmcted to produce gasoline and other hydrocarbon fuels to fill the lack of petroleum resources in South Africa. 

Petroleum chemistry is concerned with the origin, composition, and properties of naturally occurring petroleum deposits, whether in liquid (crude oil or petroleum), gaseous (natural gas), or solid (tars and asphalts) form. All of them are essentially mixtures of hydrocarbons. Whereas natural gas contains a few lighter hydrocarbons, both crude oil and tar deposits may consist of a large number of different hydrocarbons that cannot be easily identified for molecular structure or analyzed for composition. 

British Foreign Minister Ernest Bevin once said that "The Kingdom of Heaven runs on righteousness, but the Kingdom of Earth tuns on alkanes." Well, actually he said "tuns on oil" not "runs on alkanes," but they re essentially the same. By far, the major sources of alkanes are the world s natural gas and petroleum deposits. Laid down eons ago, these deposits are thought to be derived from the decomposition of plant and animal matter, primarily of marine origin. Natural gas consists chiefly of methane but also contains ethane, propane, and butane. Petroleum is a complex mixture of hydrocarbons that must be separated into fractions and then further refined before it can be used. 

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