Condensate splitters

All of the cracking operations use naphtha as feedstock. The future developments of Taiwan s petrochemicals business are linked to developments in the refinery sector which provide the feedstock. Until recently, the supply of petroleum products was in the hands of the government owned Chinese Petroleum Corporation (another CPC ) which operated three refineries and a condensate splitter. These operations supplied the downstream petrochemical plants with naphtha. However, the advent of Taiwan s entry into the WTO has broken this monopoly and FPC has established itself as Taiwan s first private refiner. The FPC refinery was built with the intention of facilitation feed supply to its new crackers. This opening of the petroleum market is allowing the entry of other players and some of the world oil majors have begun to enter the market. 

The economics of condensate splitters are variable and depend to a large extent on an attractive differential between the condensate and naphtha products. 

D. Seddon Gas Usage and Value , PennWeU, Tulsa, Oklahoma, 2006 FACTS Inc report on production and condensate splitters is reviewed in OU Gas Journal, Feb. 20, 2006, p. 50... 

In the separation train, the gas stream is partially liquefied before entering the demethanizer at 320 bar. The overhead vapor, containing methane and hydrogen, is sent to a membrane separator in which these products are separated. The pressure of the bottoms product is reduced to 270 bar and fed to the deethanizer. In this column, the ethylene and ethane are removed in the distillate, whose pressure is reduced to 160 bar before the species are separated in the C-2 splitter. The bottoms product from the deethanizer, containing propylene, propane, and the heavier species, is throttled to 190 bar, mixed with the bottoms product from the condensate splitter, and fed to the depropanizer. The overhead product of the depropanizer is a mixture of propane and propylene and the bottoms product is throttled to 50 bar and sent to the debutanizer. In this column, the butylenes and butadiene are separated from the SCN. 

Example 1 Calculation of FUG Method A large hutane-pentane splitter is to he shut down for repairs. Some of its feed will he diverted temporarily to an avadahle smaller column, which has only 11 trays plus a partial rehoiler. The feed enters on the middle tray. Past experience on similar feeds indicates that the 11 trays plus the rehoiler are roughly equivalent to 10 equilih-rium stages and that the column has a maximum top-vapor capacity of 1.75 times the feed rate on a mole basis. The column will operate at a condenser pressure of 827.4 kPa (120 psia). The feed will he at its huhhle point (q = 1.0) at the feed-tray conditions and has the following composition on the basis of... 

Problem A knockback condenser mounted on a C3 splitter reflux drum exhibited liquid carryover (as evidenced by the vent line icing-up). This indicated product loss from liquid caixying over rather than dripping back into the reflux drum. Also the vent line metallurgy would not withstand the cold temperatures produced. 

Fig. 1. Typical locations for CAM components, showing the photometer, 1 filter wheel, 2 monochromator, 3 shutter and aperture unit, 4 beam splitter, 5 accessories for polarized light such as a rotary analyzer and a compensator, 6 beam splitter for epi-excitation fluorescence, 7 objective lens, 8 stage, 9 substage condenser, 10 condenser aperture, 11 polarizer, 12 field aperture for photometry, 13 shutter, 14 primary illuminator, 15 arc lamp, 16 shutter, 17 monochromator, 18 filter wheel, 19 and ocular, 20.

J0. A Cj Splitter column uses vapor reoompression. Bei use of the low temperature required to stay below the critical temperatures of ethylene and ethane, the auxiliary condenser must be cooled by a propane refrigeration system. 

Take two pumps, a boiler, a turbine, a reheater, another turbine, a splitter, a mixing chamber (open feed-water heater), and a condenser from the inventory shop and connect the devices to form the regenerating Rankine cycle. Switch to analysis mode. 

Assume a process each for the eight devices (1) turbines as adiabatic with 80% efficiency, (2) splitters as nonisopar-ametric devices, and (3) condensers as isobaric processes. Notice that throttling devices are automatically constant enthalpy processes. 

The more volatile isobutylene product component flows upward through the upper distillation section 10 to a reflux splitter, 13, and then to a reflux condenser, 14, where it is cooled by room temperature water and withdrawn via line 14. Reflux is recirculated within the splitter 13 by a reflux line. 

It is of interest primarily for very uniform ultra-thin films and coatings (0.002-5 mils) in applications such as electrical resistors, thermistors, thermocouples, stator cores, connectors, fast-sensing probes, photo cells, memory units, dropwise steam condensers for recovery of sea water, pellicles for beam splitters in optical instruments, windows for nuclear radiation counters, panels for micrometeorite detection, dielectric supports for planar capacitors, encapsulation of reactive powders, and supports in x-ray and optical work. Any significant growth would depend upon a major breakthrough in process techniques and a consequent lowering in price. 

I well remember one pentane-hexane splitter in Toronto. The tower simply could not make a decent split, regardless of the feed or reflux rate selected. The tower-top pressure was swinging between 12 and 20 psig. The flooded condenser pressure control valve, shown in Fig. 3.1, was operating between 5 and 15 percent open, and hence it was responding in a nonlinear fashion (most control valves work properly only at 20 to 75 percent open). The problem may be explained as follows. 

Most volatile mixtures have a relative volatility that varies inversely with column pressure. Therefore, their separation requires less energy at lower pressure, and savings in the range of 20 to 40 percent have been achieved. Column pressure can be minimized by floating on the condenser, i.e., by operating the condenser with minimal or no restrictions. In some columns, such as the propylene-propane splitter, pressure can be left uncontrolled. Where it cannot, the set point of the... 

A beam splitter is placed in the light beam such that it is between the focal point of the condenser and the condenser. The light beam is divided into two beams which will be used as a sample and reference beam. After the sample and reference cells, quartz lenses are used to focus on entrance slits. 

The economics of VRD favors separations involving components with similar boiling points (e.g., the separation of propane and propylene in an oil refinery, in a column that is typically referred to as a C3 splitter ) so that the temperatures of the top and bottom streams of the distillation column are close. This reduces the power consumption of the compressor as well as the duty (and associated heat-transfer area) of the trim condenser. Given the above, we can make the following observations and assumptions concerning the various steady-state energy flows in the process. 

---