Debutanizer column

Figure 9-4. The Octol Oligomerization process for producing Os s and Ci2 s and Cis s olefins from n-butenes (1) multitubular reactor, (2) debutanizer column, (3) fractionation tower.

To make this an interesting, realistic problem, let s say the preceding feed analysis is to be fed to a debutanizer column at its bubble point. Find the feed bubble point at an 85-psig pressure, 99.7 psia. Running the program, we find that the system feed is all liquid at 202°F and has these resulting mass compositions at 203°F ... 

Example Continuing with the same debutanizer feed problem, now find the feed analysis of vapor and liquid if 50%, molar, of the feed is to be fed as a vapor to the debutanizer column. Also find the cooler duty for this condition. 

Two types of polymerization units are designed by Universal Oil Products Company. The U.O.P. Reactor-type unit contains the catalyst in tubes which are surrounded by water in a jacket for the purpose of removing the heat liberated by the exothermic polymerization reaction. The steam generated in the water jacket normally is used to preheat the feed. A feed-to-products heat exchanger furnishes the remaining heat requirements. Conventional depropanizer and debutanizer columns are used to fractionate the product. Figure 3 shows a flow diagram of a reactor type of polymerization unit. 

Description The TAC9 process consists of a fixed-bed reactor and product separation section. The feed is combined with hydrogen-rich recycle gas, preheated in a combined feed exchanger (1) and heated in a fired heater (2). The hot feed vapor goes to a reactor (3). The reactor effluent is cooled in a combined feed exchanger and sent to a product separator (4). Hydrogen-rich gas is taken off the top of the separator, mixed with makeup hydrogen gas, and recycled back to the reactor. Liquid from the bottom of the separator is sent to a stripper column (5). The stripper overhead gas is exported to the fuel gas system. The overhead liquid may be sent to a debutanizer column or a stabilizer. The stabilized product is sent to the product fractionation section of the UOP aromatics complex. 

The reformate produced in the OCR Platforming unit is sent to a debutanizer column, which strips off the light ends. The debutanizer bottoms are sent to a reformate splitter (3). The C7 fraction from the overhead of the reformate splitter is sent to a Sulfolane unit (4). The C8+ fraction from the bottom of the reformate splitter is sent to a xylene fractionation section. The Sulfolane unit extracts the aromatics and then individual high-purity benzene and toluene products are recovered in a BT fractionation section (5 6). 

Institut Frangais du Petrole (IFP) has developed a process, where pervaporation of methanol is used to debottleneck MTBE production. In the debutanizer columns used in MTBE processing, the MTBE/ methanol azeotrope results in a concentration of methanol at a point midway between the feed tray and the... 

A debutanizer column is to be designed to separate a hydrocarbon mixture. The following data is given ... 

EXAMPLE 15.3 DEBUTANIZER COLUMN—PACKING VERSUS TRAYS... 

Component Feed, Ibmole/hr Case 1, Deisobutanizer Column First, Ibmole/hr Case 2, Debutanizer Column First (fCs is HK), tbmole/hr Case 3, Debutanizer Column First (C Is Wff). Ibmole/hr ... 

Very high isobutene conversion, in excess of 99%, can be achieved through a debutanizer column with structured packings containing additional catalyst. This reactive distillation technique is particularly suited when the raffinate-stream from the MTBE unit will be used to produce a high-purity butene-1 product. 

A debutanizer column is considered as a typical case. A mixture of 50 mol% -butane ( C4) and 50mol% -pentane ( C5) is separated in a column with 61 stages. The feed flow rate is lOOkmol/h and the feed is introduced on Stage 23 (using the Aspen notation that the condenser is Stage 1). The design specifications are 1 mol% C5 impurity in the distillate and 1 mol% nCA impurity in the bottoms. The reflux-drum pressure is set at... 

Quench column 6 Gas purification 7 Drier 8 Low-temperature cooler 9 Hydrogen/ methane separation 10 Demethanization column 11 Deethanization column 12 Acetylene hydrogenation 13 Ethylene column 14 Depropanization column 15 Methylacetylene hydrogenation 16 Propylene column 17 Debutanization column 18 Depentanization column 19 Residue column... 

Air coolers Reaction effluent Debutanizer column overhead Fractionation column overhead Naphtha splitter overhead... 

The main equipment in the naphtha stabilizer section is the debutanizer. Similar to the previous discussions, we can identify key indicators for the debutanizer column ... 

Variability assessment starts with a simple statistical analysis of operating data. For example, the operating data for Cs% in the debutanizer column overhead product under normal conditions can be extracted from the historian as shown in Figure 4.5a with specification limit provided. To understand the variability, data in Figure 4.5a are converted to a normal distribution curve, which represents frequency of observations as shown in Figure 4.5b. In many cases, the operating data mimic the normal distributions. 

Let us look at an example that consists of a debutanizer column (Figure 14.1) for which White (2012) gave excellent explanations. This example gives perspective and guidelines in principles for optimizing a separation column and this example is reproduced here with permission from AIChE. 

The conclusion is that operating targets should be a function of energy costs rather than a fixed number even with fixed composition limits. It is common to observe separation columns operating at reflux rate that are 50% higher than the optimum. For the debutanizer column operation discussed here, such an operation could cost operating margins in excess of 500,000 per year. 

The cracked gas leaving the furnace section of a steam cracker contains many chemical components. They are separated by a series of fractionation columns. The bottom stream from the debutanizer column, known as the pyrolysis gasoline in the industry, contains the C5 and heavier fractions of the cracked gas. Typically, CPD plus DCPD constitute 15-25 wt% of the pyrolysis gasoline. Because CPD dimerizes readily, it is usually recovered in the form of the DCPD. 

Debutanizer—Column that removes C-4 hydrocarbons from the feed. 

---