Plate Interceptor CPI

The size of CPI separator is based on the calculation of rise rate of oil droplets, determined as 

It is believed that the conventional separator is not effective for removal of droplets smaller than 150 pm (21). Theoretically, size of conventional separator that can remove very smaller droplets may be too large that the CPI separator would be more cost-effective. 

The size of the CPI separator can be calculated from the expected plate angle, D (as degrees), then identify the required total plate area, A. The degree of plate angle can be determined as follows  

Routine operational control and maintenance is needed for this type of oil-water separator. Plate cleaning is essential, in order to remove settleable solids, which accumulate on the plates. Moreover, installation of a trash rack or screening with the opening smaller than plate space will prevent this problem. 

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Another type of gravity separator used for small amounts of oily water, the oil interceptor, is widely used both offshore and onshore. These devices work by encouraging oil particles to coalesce on the surface of plates. Once bigger oil droplets are formed they tend to float to the surface of the water faster and can be skimmed off. A corrugated plate interceptor (CPI) is shown below and demonstrates the principle involved. However there are many varieties available. Plate interceptors can typically reduce oil content to 50-150 ppm. 

Plate coalescers. Various configurations of plate coalescers have been devised. These are commonly called parallel-plate interceptors (PPI), corrugated-plate interceptors (CPI) or cross-flow separators. All of these coalescers depend on gravity separation to allow oil droplets to rise to a plate sur-... 

Subsequent improvements involved the use of corrugated plates built as a pack within a box shaped frame. The pack was installed in the separator on an angle These designs are called corrugated plate interceptors (CPI)... 

Ftg, S—CPI, or corrugated-plate interceptor, olten used on offshore platforms, requires less deck space than conventional paraDel-oiaie designs. OH coalesces in channels formed t y plate corrugations. 

Fig. 6. Schematic diagram of corrugated plate interceptor separator (CPI). [Adapted from Romano (20).]...

Parallel plate interceptors, such as CPIs (corrugated plate interceptors) and cross-flow separators, can be effective at removing suspended solids from water. However, the solids tend to cling to the plates and plug the plate pack. For this reason, parallel plate interceptors are not normally used to remove large quantities of solids from water. 

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