Insulation brick lining

When heavier refractories are required because of operating conditions, insulating brick is installed next to the shell and firebrick is installed to protect the insulating brick. Industrial experience in many fields of application has demonstrated that such a lining will successfully withstand the abrasive conditions in the bed for many years without replacement. Most serious refractory wear occurs with coarse particles at high gas velocities and is usually most pronounced near the operating level of the fluidized bed. 

Horizontal tube supports are made of refractory steel to withstand the high temperatures. Hangers for vertical tubes make for a less expensive construction per unit of tube surface. Furnaces are lined with shaped light weight refractory brick 5-8 in. thick. A 1 in. layer of insulating brick is placed between the lining and the metal shell. 

Clay fuses at from 2800 tit 3200T. tl53fi to 1760 0 the uppet limit being for flint clay and the lower for the plastic form which, due to its cc-mcming qualities, is especially valuable in fire-brick manufacture, Red brick is not suitable for refractory service, nor is insulating brick. There are several fire-clay furnace cements on the market that arc adaptable to monolithic lining. The standard sire of fire-brick and insulating brick is 9 inches by 4i inches by 2i inches 122.9 by 11.4 by 6.4 centimeters). 

The brick lining (if one is required to provide thermal insulation or mechanical protection to the bag membrane) is then laid within the bag. In cylindrical contoured vessels, properly designed, this type of lining has been moderately successful. It is not often recommended for rectangular shapes since the movement of the wooden walls is somewhat more difficult to control. It is important that, in such cases, the walls be adequately braced externally to prevent movement. The bands on cylindrical tanks and tie rods of rectangular vessels should be adjusted to the proper tension prior to the installation of any liner, and bands on the former be secured to shell wall to maintain their positions. 

As an internal insulation in a process vessel, reducing the surface temperatures on the membrane to an acceptable level. Examples (1) Steel pickling tank in a steel mill, lined with rubber sheet. Top service temperature of the rubber 160°F, but bath temperature 210°F. The brick lining provides sufficient insulation to get the surface temperature of the rubber sheet down to 140°F. (2) The same system to protect the membrane in process vessels or (3) to prevent live steam from cutting out the asphalt membrane on a floor. 

As the internal temperature rises to 200°F, the brick try to expand. The brick act as thermal insulation so that if the tank is standing in a room with an ambient temperature of 70°F, the steel shell temperature will be approximately 120°F. Although the steel has a much higher coefficient of expansion than the brick, it is only 50° hotter than it was when the brick lining was installed at 70°F. However, the brick (and mortar) on the inside face are now 130°F hotter than when they were installed, and they will expand accordingly. In addition. 

Brick cannot, of course, be used to line the underside of a flat cover, if the cover is fixed in place, and is a dome, then it can be brick-lined. What, then, can be done to provide insulation protection for the underside of a flat cover From at least the first decade of the 20th century to 1975, no insulation over the membrane could be provided. The following procedure has been used for concrete tanks. 

FIGURE 12.2 Cross-sectional diagram of a typical aluminum reduction pot using prebaked carbon anodes. The refractory brick lining and the frozen crust beside and on top of the molten electrolyte provide thermal insulation, which raises overall energy efficiencies. (Courtesy of Aluminum Co. of America.)... 

Rotating equipment, except brick-lined vessels, operated above ambient temperatures is usually insulated to reduce heat losses. Exceptions are direct-heat units of bare metal construction operating at high temperatures, on which heat losses from the shell are necessary to prevent overheating of the metal. Insulation is particularly necessary on cocurrent direct-heat units. It is not unusual for product cooling or condensation on the shell to occur in the last 10 to 50 percent of the cyhnder length if it is not well insulated. 

Officials from the Army and Westinghouse Anniston, which operates the chemical weapons incinerator for the government, said Thursday they believe the bolts broke because a lining of insulating bricks inside of the steel cylinder was replaced incorrectly after the last of the sarin was destroyed. 

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