Three-phase decanter

The separation section will change accordingly (Figure 10.11). The lean gas with only 25% VAM from the initial gas and free of acetic acid is sent to the absorption column (C-l). The column (C-2) is no longer necessary. The bottom from (T-l) is led directly to (C-3). Less water means lower reflux from the three-phase decanter. In consequence, the duty of the column (C-3) can be reduced from 30 MW to about 8.5 MW, which represents a considerable energy saving of about 70%. In this way the reboiler duty of (C-3) can be covered entirely by the steam produced in the reactor. 

The three-phase decanter is a common variant for the separation of oil, water and solids. In these designs the cake is separated and removed as in the... 

This type of decanter is patented [3] and built by Westfalia. and is used for countercurrent extraction. It is similar to a three-phase decanter, except that the second liquid phase is purposely added separately to pass, in the bowl, through the first liquid phase. The two liquid phases are caused to run countercurrently in the bowl and the wanted product is leached from one phase into the other. Separate designs are available each for heavy and light raffinate. This type of decanter is often used in the pharmaceutical industry. 

The gaps under cones are usually around half the pond depth. However, much smaller gaps have been used in vegetable oil refining (in a three-phase decanter). Uniquely in vegetable oil refining a double concentric cone has been used where the caustic soda wash is fed between the cones, rhe wash exits at the periphery of the cones under the surface of the oil. 

A further modification of these five basic uses is the three-phase decanter, in which two immiscible liquids exist as well as the suspended solids that are involved in the separation. Here good clarification of both liquids is usually required, as well as "dewatering of the solids from both liquids. 

For any waste which is produced carrying an oily liquid as well as water, then the oil can be recovered separately from the water and the suspended solids, by the use of the three-phase decanter. This will occur especially in the oil refining and blending processes, but also in several food industry applications. The treatment of refinery slop oils is an important decanter application. 

As with other major industries, there are many components of the food industry, using water in the processing, which give rise to liquid wastes carrying material in suspension. It is unlikely that these wastes can be processed for full recycle, but several can recover some value (for animal feed, for example). All will need dewatering, before final discharge. Where fat or oil are involved, as well as water, then the three-phase decanter can be used in the dewatering process. 

The press effluent is separated in a three-phase decanter into oil, water, and residual meal. In addition to its three-phase design, the fish meal decanter will have full erosion protection, with standard tiles, and a variable speed back-drive. 

Three-phase decanter tests generally do not require polymer, although some waste oil processes have used polymer. However, by definition, a second... 

The total flow of thickened cake is usually obtained by calculation, but a check can be made by measuring the time intervals between discharge of the sump tank. This would be how the oil flow is measured from a three-phase decanter. 

First, the coagulator, which worked as a long slightly elevated transportation screw that doubled as a steam driven heat exchanger, pulled up product while heating and liquidizing its fat content. The product then entered the press machine where mechanical pressure separated liquid from solid product. The liquid was pumped to three-phase decanters in which it got separated into liquid raw fat, wastewater and a... 

The raw starch milk streams are freed from insolubles - small gluten particles, fibers and insoluble pentosans by rotating screens, DSM screens or jet refiners. These by-products are collected and shipped directly as slurry for feeding or may be concentrated and/or dried together with concentrated solubles and bran as wheat gluten feed. Solubles may appear in the B-starch stream or in the light phase effluent of a three-phase decanter centrifuge. They contain the soluble pentosans, low-molecular carbohydrates and peptides, minerals and the d.s. of recycled production liquids. 

The disc-stack centrifuge is easily able to separate two liquids (for which it was originally designed), and somewhat less easily a separate solid phase. The decanter was developed as a way to clarify a single liquid stream effectively, with quite high feed concentrations. However, a decanter has now been developed that can handle two immiscible liquids. The three-phase decanter has the same kind of solid discharge (except that the upper liquid layer may be kept from the beach), but has two sets of liquid layer discharges at the other end. 

---