Free Water knockouts and Treaters

  1. Treaters or Heater Treaters: Treating systems have long been one of the most expensive and troublesome of all lease surface equipment. Also, there has been little data available for accurately sizing treating equipment, and as a result, treating equipment is frequently over or undersized. Selection of the best type of treating system and accurate determination of sizes required can save considerable expense.
  2. Selection criteria:
        1. Tightness of the emulsion
        2. Specific gravity of the oil and produced water
        3. Corrosiveness of the crude, oil, produced water and casing head gas
        4. Scaling tendencies of the produced water
        5. A quantity of the fluid to be treated and percent water in the fluid
        6. Availability of sales line for the casing head gas produced
        7. Desirable operating pressures for equipment
        8. Paraffin and asphaltene tendencies of the crude oil
  • Free Water Knockouts, Skimmers etc.: Where large amounts of free water are produced with the rude oil, such as in secondary recovery installations, it may be desirable to install free water knockouts ahead of the treating system. Free water knockouts which separate large amounts of free water from the crude oil emulsion offer advantages in reducing the size of treating equipment and the amount of heat and fuel required. Free water knockouts are often recommended where the incoming emulsion water cut exceeds 30% of the total volume. Sivalls has pioneered combination units with a built-in free water knockout section inside a treater.
  1. General equipment sizing and theory: in standard separation, one may normally expect the heavier water droplets to settle out of the oil phase due to the differences in densities between water and oil. There are two phenomena which may prevent this separation from occurring: Brownian Movement, and Electrical Charges due to Dissolved Ions. Brownian Motion occurs when droplets are too small in diameter causing them to be suspended indefinitely in the emulsion.  Dissolved Ions will cause droplets to repel each other, causing them to fail to coalesce into larger enough droplets to settle or rise rapidly. The settling rates for various diameter droplets may be calculated for any gravity and viscosity of the two fluids by Stokes Law. Stokes Law states that the settling velocity of spheres through a fluid is directly proportional to the difference in densities of the sphere and the fluid, and inversely proportional to the viscosity of the fluid and the square of the diameter of the sphere. From the settling rate of the spherical droplets and the cross-sectional area of the settling zone, we can calculate the capacity of any treating vessel for the conditions for which the settling rate was calculated.
  2. Your Sivalls Technical Sales Representative will be able to draw from experience in treating dating back to 1947, and recommend the optimal treating equipment, from vertical to horizontal treaters and free water knockouts, while taking into account the key factors of ambient conditions, retention time, heat required, specific gravity and viscosities as well as chemical makeup of your emulsion to treat you right!
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