Backing line vessel

High-quality bricks and tiles are used for lining vessels, ditches and to cover floors. The linings are usually backed with a corrosion-resistant membrane of rubber or plastic, placed behind the titles, and special acid-resistant cements are used for the joints. Brick and tile linings are covered in a book by Falcke and Lorentz (1985). 

Polypropylene is used to line vessels and piping. The material may be joined by thermal fusion. In order to be bonded to a substrate, polypropylene sheets must have a backing imbedded since PP by itself can not be bonded. If no backing is imbedded, the liner will be loose. Piping is lined with extruded material and installed in the pipe as a loose Uner. 

Install flame arresters on atmospheric vents to prevent fire on the outside of the tank from propagating back into the vapor space inside the tank. Provide fire resistant insulation for critical vessels, piping, outlet valves on tanks, valve actuators, instruments lines, and key electrical facilities. Provide remote controlled, automatic, and fire-actuated valves to stop loss of tank contents during an emergency provide fire protection to these valves. Valves should be close-coupled to the tank, and must be resistant to corrosion or other deleterious effects of spilled fluids. Vessels should be provided with overpressure relief protection. 

Use minimum flow recirculation lines piped back to feed vessel... 

Pilot-operated valves have the advantage of allowing operations n the set point v/ith no leakage, and the set position is not affected by ba pressure. However, they will not function if the pilot fails. If the sens line fills with hydrates or solids, the valve will open at 25% over pressure trapped above the disc (usually the normal operating pre the vessel). For this reason they should be used with care in dirty vice and liquid service. They are used extensively offshore where all platform relief valves are tied into a single header because up to 5 back-pressure will not affect the valve capacity. 

Positive pumps are normally fitted with relief valves. These are not usually fitted to centrifugal pumps unless the process material is likely to explode if it gets too hot. As an alternative to a relief valve, such pumps may be fitted with a high-temperature trip. This isolates the power supply. Or a kick-back, a small-diameter line (or a line with a restrietion orifice plate) leading from the delivery line baek to the suction vessel, may be used. The line or orifice plate is sized so that it will pass just enough liquid to prevent the pump from overheating. Small-diameter tines are better than restriction orifice plates as they are less easily removed. 

When the reboiler was brought back on line, the water was swept into the heat transfer oil lines and immediately vaporized. This set up a liquid hammer, which burst the surge tank. It was estimated that this required a gauge pressure of 450 psi (30 bar). The top of the vessel was blown off in one piece, and the rest of the vessel was split into 20 pieces. The hot oil formed a cloud of fine mist, which ignited immediately, forming a fireball 35 m in diameter. (Mists can explode at temperatures below the flash point of the bulk liquid see Section 19.5.)... 

Disk burst pressure to be 10 psig. MAWT of vessel is 50 psig. Discharge line back pressure is 1 psig. 

Never connect the cylinder directly to vessels of liquid since suck-back into the cylinder may result in violent reaction. Insert a trap in the line between the chlorine supply and the receiver of sufficient capacity to accommodate all the liquid. 

Noncondensable gases leaving the condensation vessels were depressurized (by means of an electronic back-pressure, Brooks Instrument model 5866), totalized (by means of an on-line flow gas meter, Ritter model TG05-5), and periodically analyzed with an on-line GC (Hewlett-Packard model 6890) equipped with three columns and two detectors for the analysis of Cj-C10 hydrocarbons (A1203 plot capillary column connected to a flame ionization detector), H2, CH4,... 

The procedure is reversed for placing the vessel back into service. In this case the procedure begins at point B in Figure 6-7, with the vessel containing air. If the vessel is closed and methane is pumped in, then the gas composition inside the vessel will follow the air line and finish at point A. Again, the mixture is flammable as the gas composition moves through the flammability zone. 

An extended line, sometimes called a dip leg or dip pipe, reduces the electrical charge that accumulates when liquid is allowed to free fall. When using dip pipes, however, care must be taken to prevent siphoning back when the inlet flow is stopped. A commonly used method is to place a hole in the dip pipe near the top of the vessel. Another technique is to use an angle iron instead of a pipe and to let the liquid flow down the angle iron (see Figure 7-21). These methods are also used when filling drums. 

Blood is pumped away from the heart through arteries it permeates the tissues through networks of very small capillaries where nutrient delivery, gas exchange and waste removal occur and is finally returned to the heart via the veins. The structures of the arteries and veins differ in important ways. First, the veins have one-way valves which prevent the back-flow of blood and second, the walls of the arteries are much thicker, due largely to the layer of smooth muscle cells. Both types of vessel are lined on their inner surface with endothelial cells. Refer to Figure 5.2. 

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