Method and apparatus for recovering waste oil

Claim 2

Method of recovering oil from a mixture of oil, water, including emulsions of oil and water, and suspended solids and polymers, which comprises the steps of: heating the mixture; adding a de-emulsifier to the heated mixture; passing the heated mixture with the de-emulsifier added thereto through a first vibrating screen to remove large particles and to mix thoroughly the de-emulsifier with the mixture; adding a surface tension reducer in the heated mixture after passing said mixture through said first vibrating screen; processing said mixture with said surface tension reducer added thereto through a hydrocyclone to remove suspended solids and to agglomerate polymers contained in said mixture; passing said mixture after said processing step through a second vibrating screen to remove said agglomerated polymers; and allowing said mixture passed through said second vibrating screen to settle, whereby the oil separates from the water.

Claim 3

The method as claimed in claim 1, wherein said heating step is performed in the range of 120° F. to 140° F.

Claim 4

The method of claim 1, wherein said processing step includes the steps of: depositing said mixture in a catch basin: withdrawing said mixture from said catch basin; subjecting said mixture to primary hydrocyclone separation to remove most of said particulate matter from said mixture and to agglomerate a portion of said polymers; depositing said primarily separated mixture into a receiving vessel; withdrawing primarly separated mixture from the lower portion of said receiving vessel; and subjecting said primarily separated mixture to secondary hydrocyclone separation to remove substantially all of said particulate matter from said mixture and to agglomerate substantially all of said polymers.

Claim 5

Apparatus for recovering oil from a mixture of oil, water, dissolved and suspended solids and dissolved polymers, which comprises: a holding tank for collecting and holding the mixture; means for heating the holding tank, thereby heating the mixture; means for removing the heated mixture for the holding tank; means for injecting into the heated mixture removed from the holding tank a de-emulsifier; a first vibrating screen separator positioned to receive the heated mixture with the de-emulsifier added thereto to remove debris and large solid particles from said mixture; means for receiving the mixture discharged from the first vibrating screen; means for injecting a surface tension reducer into the mixture discharged from the first vibrating screen; hydrocyclone means for separating solids suspended in said mixture and agglomerating polymers dissolved in said mixture to form a mixture of oil, water and suspended agglomerated polymers; a second vibrating screen separator positioned to receive the mixture of oil, water and suspended agglomerated polymers to separate the agglomerated polymers from the oil and water; and a settling tank positioned for receiving the oil and water discharged from the second vibrating screen and allowing the oil and water to separate from each other.

Claim 6

Apparatus for recovering oil from a mixture of oil, water, dissolved and suspended solids and dissolved polymers, which comprises: a holding tank for collecting and holding the mixture; means for heating the holding tank, thereby heating the mixture; means for removing the heated mixture for the holding tank; means for injecting into the heated mixture removed from the holding tank a de-emulsifier; a first vibrating screen separator positioned to receive the heated mixture with the de-emulsifier added thereto to remove debris and large solid particles from said mixture; means for receiving the mixture discharged from the first vibrating screen; means for injecting a surface tension reducer into the mixture discharged from the first vibrating screen; hydrocyclone means for separating solids suspended in said mixture and agglomerating polymers dissolved in said mixture to form a mixture of oil, water and suspended agglomerated polymers; a second vibrating screen separator positioned to receive the mixture of oil, water and suspended agglomerated polymers to separate the agglomerated polymers from the oil and water; and a settling tank positioned for receiving the oil and water discharged from the second vibrating screen and allowing the oil and water to separate from each other.

Claim 7

The apparatus as claimed in claim 4, wherein said liquid receiving means includes: a catch tank positioned to receive the mixture discharged from said first vibrating screen.

Claim 8

The apparatus as claimed in claim 5, wherein said hydrocyclone separating means includes: a plurality of liquid receiving vessels positioned adjacent said catch tank; first transfer means for receiving said mixture from said catch tank; a primary hydrocyclone bank connected to said first transfer means, said primary hydrocyclone bank including a plurality of hydrocyclones, each adapted to receive said mixture and separate therefrom a substantial quantity of said suspended solids and agglomerate a portion of said dissolved polymers; means for transporting the liquid discharged from said primary hydrocyclone bank to a first of said plurality of liquid receiving vessels; second transfer means for removing the liquid in said first liquid receiving vessel; a secondary hydrocylone bank connected to said second transfer means, said secondary hydrocyclone bank including a plurality of hydrocyclones, each adapted to receive said liquid and separate therefrom substantially all of the suspended solids and agglomerate substantially all of said dissolved polymers; means for transporting the liquid discharged from said secondary hydrocyclone bank to a second of said plurality of liquid receiving vessels; and means for transporting the liquid in said second liquid receiving vessel to said second vibrating screen.