Tanks, heating liquids

Ii takes 1800 s to heat a tank of liquid from 293 to 333 K using steam supplied to an immersed coii when the steam temperature is 383 K. How long will it take when the steam temperature is raised to 393 K The overall heat transfer coefficient from the steam coil to the tank is 10 times the coefficient from the tank to surroundings at a temperature of 293 K and the area of the steam coil is equal to the outside area of the tank... 

For jet fuel the energy of explosion is 18,590 Btu/lb and the molecular weight is 160. 6-30. You have decided to purchase a 500-gal tank of liquid propane (C3H8) to heat your house during the winter. You are concerned about tank rupture and the possibility of a vapor cloud explosion of all the propane. How far away (in ft) must the tank be from the house to ensure that your house will receive only minor damage from an explosion The specific gravity of liquid propane is 0.500, and the energy of explosion for propane is 503.9 kcal/g-mol. 

For tanks containing liquids with flash points greater than 140°F (60°C), no protection is required unless, under normal operation, the material entering the tank or in the tank is heated to within 30°F (15°C) of its flash point. 

Tanks are used in innumerable ways in the chemical process industry, not only to store every conceivable liquid, vapor, or solid, but also in a number of processing applications. For example, as well as reactors, tanks have served as the vessels for various unit operations such as settling, mixing, crystallization (qv), phase separation, and heat exchange. Herein the main focus is on the use of tanks as liquid storage vessels. The principles outlined, however, can generally be applied to tanks in other applications as well as to other pressure-containing equipment. 

An extremely important safety consideration for both heated and cryogenic tanks is that lower boiling liquids must not be introduced into the tank. These liquids can boil and cause a frothover or a violent evolution of vapor, followed by tank failure. 

Pitch. Pitch used to be stored in solid form at the tar distillery in open bays, from which it was removed by small explosive charges. Loading of the lump pitch by mechanical shovel created a dust hazard both at the tar installation and at the customers, where the lumps had to be ground before use. In the 1990s, pitch is stored in tanks heated by superheated steam or circulating hot-oil coils and transported in liquid form in insulated rail, road tankers, or ships. When transport as a hot liquid is not feasible, not acceptable by the customer, or for small amounts, the pitch is converted into a dust-free particulate form, ie, short rods termed pencils, pastilles, or flakes. 

There are two basic evaporator designs that are typically used atmospheric and vacuum evaporation (Metals Handbook 1987). Atmospheric evaporation principles are similar to those of a heated open tank, with the exception that the heated liquid is sprayed over plastic packing in order to increase its surface area and accelerate evaporation. Atmospheric evaporators on chrome plating lines have sometimes been used simultaneously as evaporators and as plating bath fume scrubbers. Atmospheric evaporators are considerably less expensive than vacuum evaporators. Typical atmospheric evaporator capital costs range from 2500 to 4000, while vacuum evaporator costs can be an order of magnitude or more higher. In atmospheric evaporator systems, however, vaporized water is not recovered, as it can be in vacuum systems. 

The rate of heat transfer from the tank to the surroundings = UtAj(T — 288) where Ut is the effective overall coefficient and AT the surface area of the tank and liquid surface. In this case ... 

In a fire, a tank containing liquid is most vulnerable in the shell at the vapor space because very little heat can be absorbed by the vapor, and the metal in the vapor space can heat up... 

Approximately 150 SCFM (standard cubic feet per minute) of nitrogen is required by a process facility. As shown in the diagram below, plans call for supplying the facility from a tank of liquid nitrogen (SG 0.81) at its normal boiling point (—SSO ) and 1 atm. Nitrogen vapor leaves the tank and is compressed and heated to obtain the desired conditions, 150 F and 600 psia. 

The actual heat consumption is several times higher than the above theoretical values, as a result of heat losses. The thermal efficiency of glass tanks heated with gaseous or liquid fuels is then in the range of 20 — 35%, that of all-electric furnaces amounts to 60—80% (not taking into account the efficiency of electric power generation). In the case of pot furnaces the thermal effiency is very low, about 10% or less. 

The simplest continuous evaporation system is the single stage flashing of a heated liquid into an expansion tank orflash which is maintained... 

In a batch-feed operation, 100 mol of pure liquid is added at the rate of 2 mol/min to a tank of liquid solution initially containing 100 mol of pure A. The tank is stirred, and its contents are assumed to be thoroughly mixed and uniform in composition at all times. The tank is jacketed to provide for heat removal to keep the tank contents at a constant temperature of 300°K. The pressure is constant at 1 atm. 

Turbines, propellers, and paddles power = 0.2 to 1.5 kW/m for mixing liquids with impeller discharge rate >20 x liquid flow rate into tank. Heat transfer, 0.4 to 2 kW/m but don t neglect heat input from the mixer mass transfer 2 to 4 kW/mT Turbines, propellers, and paddles power = 1 to 4 kW/m for mass transfer. Air agitation diffused air 0.3 to 0.5 NdmVs-m 1.5 to 6 dmVs m... 

The sulfur dioxide-rich citrate solution in the bottom of the absorber is fed by level control through a steam-heated exchanger to a three-stage continuous stirred tank reactor system countercurrent to a flow of hydrogen sulfide gas. For this installation the gas source is a tank of liquid hydrogen sulfide. 

Your family might use small tanks of liquid propane as fuel for your barbecue grill or larger tanks for heating and cooking. 

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