The oil-water separator API is a tool designed to separate gross crude oil and suspended solids from discharges of liquid waste from oil refineries, petrochemical plants, chemical plants, natural gas processing plants and other industrial oily sources.. This name derives from the fact that the separator is designed in accordance with the standards published by the American Petroleum Institute (API).
Video API oil-water separator
Description of design and operation
The API separator is a gravity separation device designed using Stokes' legal principles that determine the speed of oil droplets based on the density, size and nature of the water. The dividing design is based on the specific gravitational differences between oil and waste water because the difference is much smaller than the specific gravitational difference between suspended solids and water. Based on the design criteria, most suspended solids will settle at the bottom of the separator as a sediment layer, the oil will rise above the separator, and the waste water will be the middle layer between the above oil and solids. under. The API Design Standard, when applied correctly, makes adjustments to geometry, design and size of the separator outside of simple Stokes Law principles. These include allowances for the entry of water flow and loss of turbulence out and other factors. The API 421 specification requires a ratio of length to a minimum width of 5: 1 and a minimum depth-to-width ratio of 0.3: 0.5.
Particularly in the operation of the API separator, the oil layer, which may contain incoming water and suspended solids, continues to be bypassed. This removed oily layer can be reprocessed to restore a valuable product, or discard it. The heavier lower sediment layers are removed by chain and flight dredges (or similar devices) and mud pumps.
Maps API oil-water separator
Design Limitations
API design separators, and similar gravity tanks, are not intended to be effective when any of the following conditions apply to feed conditions:
- Oil droplet size in the feed is less than 150 microns
- Oil density greater than 925 kg/m3
- Suspended solids follow oil which means 'effective' oil density greater than 925 kg/m3
- The water temperature is less than 5 oC
- There is a high degree of dissolved hydrocarbons
According to Stokes' Law, heavier oils require more retention time. In many cases where refineries have switched to heavier crude slabs, the API separation efficiency has decreased.
Further treatment of API drainage
Due to performance limitations, water discharged from API type separators usually requires some further processing stages before treated water can be disposed or reused. Further water treatment is designed to remove oil droplets smaller than 150 microns, solutes and hydrocarbons, heavier oils or other contaminants not removed by the API. Secondary treatment technologies include dissolved air flotation (DAF), Anaerobic and Aerobic biological treatments, Parallel Plate Separator, Hydrocyclone, Walnut Shell Filter, and Media filters.
Alternative Technology
Plate separators, or Combined Combat Plates are similar to API separators, as they are based on Stokes' Law principles, but include slant plate plates (also known as parallel packets). The underside of each of the parallel plates provides more surface for the suspended oil droplets to merge into larger lumps. The incorporation plate separator may not be effective in situations where aqueous chemicals or suspended solids limit or prevent oil droplets united. In operation it is intended that the sediment will slide onto the top of each parallel plate, but in many practical situations, the sediment can be attached to plates that require regular cleaning and cleaning. The separator still depends on the specific gravity between suspended oil and water. However, parallel plates can increase the degree of oil-water separation to oil droplets above 50 microns in size. Parallel parallel splitteres are added to the API Separator design and require less space than conventional API separators to achieve the same level of separation.
History
The API separator is developed by API and Rex Chain Belt Company (now Evoqua). The first API separator was installed in 1933 at the Atlantic Distillation (ARCO) in Philadelphia. Since then, almost all refineries around the world have installed API separators as the first major stage of their oily wastewater treatment plant. The majority of refineries install API separators using original designs based on the specific gravitational differences between oil and water. However, many refineries now use plastic parallel plate packaging to enhance the separation of gravity. Today's rules often require an API separator with a fixed or float cover for the control of volatile organic compounds (VOCs). Also, most API separators must be above ground to detect spills.
Other oil-water separation applications
There are other applications that require oil-water separation. As an example:
- Oily oil separator (OWS) to separate oil from hulls accumulated in vessels as required by the international MARPOL Convention.
- Oil and water separators are commonly used in electrical substations. The transformers found in substations use large quantities of oil for cooling purposes. The ditches are built around an unclosed substation to capture all leaky oil, but this will also catch rainwater. Oil and water separators therefore provide faster and easier leakage of oil. â € <â € <
See also
- Pollution
- Waste Water
- Industrial wastewater treatment
- Industrial water treatment
- Centrifugal oil-water separator
- Induction flotation gas
References
External links
- Photos, drawings and design discussions API gravimetric separator
- Oil/Water Separators Diagrams and description of separators using plastic parallel packing plates.
- Oil-in-water separation A good discussion and explanation of wastewater treatment processes.
- Monroe Environmental API Manufacturer Separators, images, photos, diagrams, case studies, and descriptions.
- Oil Water Separator Features, Case Studies, Technology, Photos
Source of the article : Wikipedia
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