Vertical furnace

Multiple hearth furnace Vertical pressure vessels... 

Experimental and computational results are shown in Fig.2 to Fig.5, and Table 1. Fig.2 to Fig.4, provide description of the species distribution for case 1, respectively CO, Oj and UHC, both in the x-y plane at the middle of the furnace (vertical cut), and in the x-z plane, in the height of the measured points (horizontal cut). An extra cut in the top of the furnace called M-10) is also presented to show the effect of the flying char combustion in the upper part of the furnace. Fig.5 presents the temperature profile in the x-y plane, at the middle of the fiimace. Table 1, finally, summarizes the calculation results of CO emissions at the outlet, together with experimental results for both case 1 and case 2. 

Horizontal straight-line continuous furnaces are more common than rotary hearth furnaces, rotary dram furnaces, vertical shaft furnaces, or fluidized bed furnaces. 

The theoretical draft (lift, suction) of a tall column of hot gas, as in a furnace, vertical duct, or stack is ... 

Submerged-Arc Furnace. Furnaces used for smelting and for certain electrochemical operations are similar in general design to the open-arc furnace in that they are usually three-phase, have three vertical electrode columns and a shell to contain the charge, but dkect current may also be utilised They are used in the production of phosphoms, calcium carbide, ferroalloys, siUcon, other metals and compounds (17), and numerous types of high temperature refractories. 

Most furnace shells are short vertical cylinders but may also be triangular, elliptical, or rectangular in plan view. Single-phase furnaces may have one or two movable electrodes. Three-phase furnaces usually have three movable electrodes, but some have six (three paks, two electrodes for each phase). 

The Stuckofen or old high bloomery appeared in Germany in ca 1300 AD. This type of furnace was 3—5 m high and enclosed a tapered vertical shaft that was 1—1.2 m in diameter. Small openings near the bottom were provided for no22les (tuyeres, pronounced tweers) that permitted air, suppHed by bellows, to be blown into the furnace. Modem blast furnaces have essentially the same fundamental design. 

Heat Recovery and Seed Recovery System. Although much technology developed for conventional steam plants is appHcable to heat recovery and seed recovery (HRSR) design, the HRSRhas several differences arising from MHD-specific requirements (135,136). First, the MHD diffuser, which has no counterpart ia a conventional steam plant, is iacluded as part of the steam generation system. The diffuser experiences high 30 50 W/cm heat transfer rates. Thus, it is necessary to allow for thermal expansion of the order of 10 cm (137) ia both the horizontal and vertical directions at the connection between the diffuser and the radiant furnace section of the HRSR. 

In fossil fuel-fired boilers there are two regions defined by the mode of heat transfer. Fuel is burned in the furnace or radiant section of the boiler. The walls of this section of the boiler are constmcted of vertical, or near vertical, tubes in which water is boiled. Heat is transferred radiatively from the fire to the waterwaH of the boiler. When the hot gas leaves the radiant section of the boiler, it goes to the convective section. In the convective section, heat is transferred to tubes in the gas path. Superheating and reheating are in the convective section of the boiler. The economizer, which can be considered as a gas-heated feedwater heater, is the last element in the convective zone of the boiler. 

A jet of gaseous oxygen is blown at high velocity onto the surface of a bath of molten pig iron and scrap at the bottom of the furnace by a vertical water-cooled retractable lance iaserted through the mouth of the vessel (Fig. 4). The furnace is mounted ia a tmnnion ring and can be tilted backward or forward. 

Incineration can be accompHshed ia multiple-hearth furnaces, ia which the sludge passes vertically through a series of hearths. In a fluidized-bed sludge, particles are fed iato a bed of sand fluidized by upwardly moving air. 

Multiple-Hea.rth Roasters. The circular types consist of a series of hearths arranged vertically in such a way that the ore entering the top is rabbled and dropped down from hearth to hearth, until it is completely oxidized. The hearths are usually stationary and the plows revolve, such as in the Wedge, Herreshoff, Ord, Skinner, and other roasters (21). In other furnaces, the hearths revolve and the rabbles are fixed, eg, the deSpirlet and its modification, the Barrier. 

At first, batchwise horizontal retorts were used for smelting, and later continuous vertical retorts, both externally fired. Continuous, internally heated furnaces such as the electrothermic furnace followed, and the last important development was the Imperal Smelting blast furnace. 

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