Hydrocarbon noncatalytic partial oxidation

As the molecular weight of the hydrocarbon increases (lower H/C feed ratio), the H2/CO product ratio decreases. The H2/CO product ratio is approximately 3 for methane, 2.5 for ethane, 2.1 for heptane, and less than 2 for heavier hydrocarbons. Noncatalytic partial oxidation of hydrocarbons is also used to produce synthesis gas, but the H2/CO ratio is lower than from steam reforming ... 

Partial Oxidation. Noncatalytic partial oxidation processes (see Fig. 22.6) react hydrocarbons with gaseous oxygen at very high... 

The noncatalytic partial oxidation of hydrocarbons by the Shell gasification process (SGP) takes place in a refractory-lined reactor that uses a specially designed burner. The oxidant is preheated and then mixed with steam... 

Several processes, including noncatalytic partial oxidation (POX), catalytic partial oxidation (CPO), and ATR may be used to perform partial oxidation of hydrocarbons. In all cases, some or all of the reactions listed in Table 4 are involved. Normally, these reactions are accompanied by the steam-reforming and shift reactions. The oxidation reactions are irreversible at all conditions of practical interest. 

The noncatalytic partial oxidation of fuel oil converts petroleum feedstock into synthesis gas, C02, CH4, and H2S if any sulfur is present. This process has the ability to handle sulfur compounds without pretreatment (sulfur removal). Eliminating a processing step from steam reforming techniques, however, requires additional equipment for oxygen addition in the reactor. The expected carbon deposition problem with hydrocarbon material containing low H C ratios is limited by the use of carbon recovery and extinction recycle schemes [28], The partial oxidation of fuel oil typically operates at a temperature range of 1200-1500°C and pressures of 30-80 bars in a refractory-lined reactor. 

At present, natural gas and light hydrocarbons are the predominant feedstocks for the production of synthesis gas. Synthesis gas can also be produced from heavy hydrocarbons or coal, but in that case noncatalytic partial oxidation processes will be used (see the section Hydrocarbon Steam Reforming). 

Supp, E. (1997) Noncatalytic partial oxidation and special gasification processes for higherboiling hydrocarbons, in UUmann s Encyclopedia of Industrial Chemistry, Fifth Edition on CD-ROM, Wiley-VCH Verlag GmbH, Wdnheim. 

Partial oxidation processes rank next to steam-hydrocarbon processes in the amount of hydrogen made. They can use natural gas, refinery gas, or other hydrocarbon gas mixtures as feedstocks, but their chief advantage is that they can also accept liquid hydrocarbon feedstocks such as gas oil, diesel oil, and even heavy fuel oil. All processes employ noncatalytic partial combustion of the hydrocarbon feed with oxygen in the presence of steam in a combustion chamber at flame temperatures between 1300 and 1500°C. For example, with methane as the principal component of the feedstock ... 

When air was used as the oxidant, the concentrations of hydrogen and carbon monoxide at the outlet of this converter reached 20% and 11%, respectively, which is dose to the thermodynamically equilibrium values. The possibility of an effective conversion of natural gas into syngas with a nearly optimal ratio of H2/CO = 2 was demonstrated. Permeable 3D matrices offer a way of designing relatively simple, compact, and efficient noncatalytic auto-thermal reformers for the partial oxidation of hydrocarbon gases of different origin and composition to syngas [331—332]. 

Synthesis gas may be prepared by a continuous, noncatalytic conversion of any hydrocarbon by means of controlled partial combustion in a fire-brick lined reactor. In the basic form of this process, the hydrocarbon and oxidant (oxygen or air) are separately preheated and charged to the reactor. Before entering the reaction zone, the two feed stocks are intimately mixed in a combustion chamber. The heat produced by combustion of part, of the hydrocarbon pyrolyzes the remaining hydrocarbons into gas and a small amount of carbon in the reaction zone. The reactor effluent then passes through a waste-heat boiler, a water-wash carbon-removal unit, and a water cooler-scrubber. Carbon is recovered in equipment of simple design in a form which can be used as fuel or in ordinary carbon products. 

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