Question

Oil and gas pipelines, which are at an elevated pressure (about 3 MPa) and sub-ambient temperature (below 298 K), may get blocked by the formation of solid hydrates. One of the strategies adopted to inhibit the formation of hydrates is the injection of Thermodynamic Hydrate Inhibitors (THIs) into the reservoir fluid.
Identify all suitable chemicals that are commonly used as THIs.

• A. Sodium Chloride
• B. Methanol
• C. Polyvinylpyrrolidone
• D. Sodium Dodecyl Sulphate

Hint:

Methanol is the most commonly used THI, and it is often injected in pipelines to prevent hydrate blockages.

Answer 1

The Correct Option is A, B

Step 1: Thermodynamic Hydrate Inhibitors (THIs) are chemicals used to prevent hydrate formation by either lowering the hydrate formation temperature or shifting the equilibrium pressure.

Step 2: Methanol is commonly used as a THI because it inhibits hydrate formation by reducing the temperature at which hydrates form. Sodium chloride can also act as a THI by lowering the freezing point.

Step 3: Polyvinylpyrrolidone and Sodium Dodecyl Sulphate are not typically used as THIs for hydrate inhibition.
Thus, the correct answer is (A) Sodium Chloride and (B) Methanol.