Distillation towers condenser

Reboiler. The case shown in Figure 8 is common for reboilers and condensers on distillation towers. Typically, this AThas a greater impact on excess energy use in distillation than does reflux beyond the minimum. The capital cost of the reboiler and condenser is often equivalent to the cost of the column they serve. 

The feed to a distillation tower is normally heated either by indirect heat exchange with hot products and/or in a furnace. The products must be condensed and cooled. This is accomplished in part by heat exchange with other petroleum streams and in part by cooling water exchange. The arrangement and relative... 

A fractional distillation tower is used to separate different compounds in petroleum. The fuels condense at different enfi efttures and produce different products. 

UK. = Light key component in volatile mixture L/V = Internal reflux ratio L/D = Actual external reflux ratio (L/D) ,in = Minimum external reflux ratio M = Molecular weight of compound Mg = Total mols steam required m = Number of sidestreams above feed, n N = Number of theoretical trays in distillation tower (not including reboiler) at operating finite reflux. For partial condenser system N includes condenser or number theoretical trays or transfer units for a packed tower (VOC calculations) Nb = Number of trays from tray, m, to bottom tray, but not including still or reboiler Nrain = Minimum number of theoretical trays in distillation tower (not including reboiler) at total or infinite reflux. For partial condenser system,... 

In our example, we obtained a rather precise fixed-capital cost estimate from a private industry with high-pressure-technology experience. This estimate, updated to year 2000, was of 600,000 EUR for the plant sketched in Fig. 8.3-2, including all costs listed in the above paragraph. In case a distillation tower was needed to obtain pure CO2 for recycling, the chemical plant would be more expensive because a flash-type separator would be substituted with a distillation tower, with boiler and condenser. 

When a vapor condenses to a liquid, we say that the latent heat of condensation of the vapor is liberated. In a steam reboiler, this liberated heat is used to reboil the distillation tower. When a vapor, or more commonly a liquid, cools, we say that its sensible heat is reduced. For a small or slight temperature change, the change in latent heat might be large, while the change in sensible heat will be very small. 

For total condensers, there are three general schemes for controlling distillation tower pressure ... 

More insight is yet available from the data in Table II. In the refrigerated process, the two condensers and the throttle valve involve more than 50% of the lost work remaining. One way to eliminate the inefficiencies of the condensers is to recycle the latent heat of the overhead vapor in a heat pump (vapor recompression) system, as shown in Figure 3. The distillation tower pressure, and hence its overhead temperature are kept the same, but the overhead, instead of being condensed, is compressed to a pressure at which it will condense at 77°F (about 180 psig). 

Solvent recovery systems would also necessitate the specification of condenser duties, distillation tower sizes, holding tanks, piping, and valves. It is important to note that the engineering design of an adsorption system should be based on pilot data for the particular system. Information can usually be obtained directly from the adsorbent manufacturer. The overall size of the unit is determined primarily by economic considerations, balancing the operating costs against the capital costs. 

The bottoms of the CD, also known as atmospheric residue, are charged to a second fired heater where the typical outlet temperature is about 750-775°F. From the second heater, the atmospheric residue is sent to a vacuum tower. Steam ejectors are used to create the vacuum so that the absolute pressure can be as low as 30-40 mm Hg (about 7.0 psia). The vacuum permits hydrocarbons to be vaporized at temperatures below their normal boiling point. Thus, the fractions with normal boiling points above 650°F can be separated by vacuum distillation without causing thermal cracking. In this example (Fig. 18.14), the distillate is condensed into two sections and withdrawn as two sidestreams. The two side-streams are combined to form cracking feedstocks vacuum gas oil (VGO) and asphalt base stock. 

A random-packed distillation tower with an inside diameter of 6 in. is being operated at a condenser pressure of 100 mm Hg. The following data are obtained during operation ... 

A special test on the 6-in. distillation tower described in Prob. 8 indicates that the total pressure drop is 2.9 mm Hg when the gas rate is 50 lb/h. For this test, the condenser pressure was maintained at 100 mm Hg, the I/G ratio was the same as shown in Prob. 8, and temperature change was negligible. Operation can be considered to be under preloading conditions. Estimate the total pressure drop at the operating conditions indicated in Prob. 8 for the 12-in. column. 

The noncondensable gas separated in the distillation tower is passed through a water scrnbber to remove HCl if PVC is present. Then the NCG is contacted with refrigerated gasoline to condense some light fractions and finally the gas is passed through a flame arrestor to a burner in the flame stack. 

VOCs emitted from chemical processes need to be treated properly using several kinds of environmental processes including oxidation, adsorption, and condensation technologies, etc.[2]. Among these technologies, adsorption process could be the first candidate for the recovery of VOCs since it can enrich VOCs in an effective way. Therefore, adsorption beds are, in general, incorporated in the VOC recoveiy systems which also include distillation towers and/or condensation systems and/or absorption towers to form hybrid systems[l]. 

The water and hydrocarbon liquids are immiscible and are separated in a settling tank decanter The water is vaporized and heated (F)to produce the steam that mixes with the ethylbenzene feed to the reactor. The hydrocarbon stream leaving the decanter is fed to a distillation tower (actually, a series of towers), which separates the mixture into essentially pure styrene and ethylbenzene, each at 25 C after cooling and condensation steps have been carried out. The ethylbenzene is recycled to the reactor preheater, and the styrene is taken off as a product. 

On a process flowsheet, distillation towers, furnaces, reactors, and large vertical vessels often are arranged at one level, condenser and accumulator drums on another level, reboilers on... 

The accompanying figure represents the schematic flowsheet of a distillation tower used to recover gasoline from the products of catalytic cracker. Is the problem completely specified, that is, is the number of degrees of freedom equal to zero for the purpose of calculating the heat transfer to the cooling water in the condenser ... 

Vented Decanters When the liquid-liquid stream to be decanted also contains a gas or vapor, provisions for venting the decanter must be included. This often is the case when decanting overheads condensate from an azeotropic distillation tower operating under vacuum, since... 

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