Coke gasification

Coal gasification to produce syngas can be regarded physically as a gas/solid reaction. From a chemical point of view, it can be considered as the partial oxidation of carbon or as the reduction of water with carbon. However the total process is much more complex and only describable using numerous 

Some other important reactions that take place are  

The different gasification processes can be characterized 1) by the type of coal used and 2) by the coal s physical and chemical properties. On the other hand, the processes differ in the technology involved. For example the heat supply can be allothermal (i.e., external heating) or autothermal (i.e selfheating) and the reactor can be fixed-bed, fluidized-bed or entrained-bed. Furthermore, the actual gasification reaction and the gas composition are determined by46  

Preferred feedstocks lignite, reactive bituminous coals, wastes bituminous coals, petcoke, wastes lignite, bituminous cants, cokes, biomass, wastes lignite, reactive bituminous ooals. wastes lignite, reactive bituminous coals, petcokes 

Ash content no limitation 25% referred no limitation no limitation 25% referred 

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The furnace (Fig. 2) maybe divided into four zones (from bottom to top). (/) Hearth and raceway as the coke descends through the furnace, it is heated by the ascending gases to about 1370°C. When it reaches the raceway in front of the tuyeres, it reacts immediately with the oxygen in the hot blast air. Equation 1, however, is actually the combination of coke combustion (eq. 6) and coke gasification (eq. 7, also referred to as solution loss). 

Coke gasification occurs just outside the raceway area where gaseous oxygen is no longer available to completely combust the CO to CO2. This reaction goes essentially to completion at temperatures between 1500 to 2100°C. The net heat effect is exothermic, as shown in equation 1. The endothermic equation (eq. 2) allows control of the temperature in front of the tuyeres by controlling the moisture in the hot blast. 

Breckenridge, W. et al., Use of SELEXOL Process in Coke Gasification to Ammonia Project, Proceedings ofLaurance Reid Gas Conditioning Conference, http //www.uop.com/objects/92Selex CokeGasifAmm.pdf, March 2000. 

Gray, D. and Tomlinson, G., Opportunities for Petroleum Coke Gasification Under Tighter Sulfur Limits for Transportation Fuels, Paper presented at the 2000 Gasification Technologies Conference, San Francisco, CA, October 8-11, 2000. 

Geosits, R. and Mohammad-Zadeh, Y., Coke Gasification Power Generation Options and Economics. Power-Gen Americas, Dallas, TX, November 1993. 

Jahanke, F. C., Falsetti, J. S., and Wilson, R. F., Coke Gasification, Costs, Economics Commercial Applications. 1996 NPRA Annual Meeting, San Antonio, TX, March 1996. 

Coke gasification, 24 501 Coke oven gas, commercial gas absorption processes for, 2 26t... 

Flexicoking integrates coke gasification with fluid coking. Product coke is converted to low heat content fuel gas reducing net coke production. Sulphur dioxide emissions are comparatively low. 

Fe(CN)6]3, as the free acid, has been used as a corrosion inhibitor for metal surfaces 55 K2[Fe(CN)6] has also been reported as being effective for this purpose.56 Both hexacyano ions act as combustion inhibitors for aromatic polymers.57 In the production of carbon monoxide by coke gasification for use in blast furnaces, additives are needed to enhance the reduction of any carbon dioxide formed back to the monoxide. Trisoxalatoiron has been found effective for this... 

Synthesis gas (CO and H2) production contributes a large fraction, approximately 60%, of the cost of methanol. The synthesis gas for methanol used to be manufactured by coke gasification, but now is almost exclusively produced by steam reforming of natural gas. 

Coal and Coke Gasification. In coal gasification the exothermic partial combustion of carbon and the endothermic water gas formation represent the actual gasification reactions 46... 

In 2000 Farmland Industries in Kansas started up a petroleum coke gasification plant to make ammonia. The plant uses Texaco s process to make 1000 tonnes per day of ammonia.185, 186 In 2004 Rentech purchased an 830-tonne-per-day ammonia plant in Illinois and plans to convert it from natural gas to coal feedstock. Startup of the conversion is expected in 20 07.300... 

The results of this investigation have indicated the importance of several variables relative to rates of coke deposition and of coke gasification. Both deposition and gasification depend, in some complex manner, on the surface composition. The present investigation indicates that important information can be obtained with the scanning electron microscope. 

The flexicoking process is an adaptation of the fluid coking process that uses the same reactor as a fluid coker but has an integrated gasification unit available for coke gasification to produce, in addition to the typical fluid coking slate of products, a low-BTU gas. 

The system of Fig. 4 is the alternative of the system of Fig.l. In this system, coal is pre-treated by liquefaction process, and the coke is used for the gasification of the system of Fig. 1. Also, two kinds of liquid fuel of oil and methanol are produced. The H2 required for liquefaction can be supplied from the gasification of coke. This system will take an important role for production of syn-oil, when oil is shortage. In this system with SCOT-solar farm (500mx600m), we assumed that 180t/day coal is treated, and that 90t/day oil (conversion efficiency =50%) by the liquefaction process and 410kl/day of methanol by the solar-assisted coke gasification are... 

In countries with cheap coal (e.g. South Africa) hydrogen is being increasingly produced by coal and coke gasification (before World War II 90% of hydrogen was produced in this way). This reaction proceeds as follows ... 

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