Method and system for controlling emissions from glycol dehydrators

In a system for extracting water from a gas stream containing quantities of water and of volatile organic compounds, which system includes a glycol regenerator including a heating section for heating moist glycol provided thereto to thereby separate and vent the moisture from same as steam and gasified volatile organics which have been absorbed by the glycol during contact with the gas stream;

• means to provide the moist glycol having contacted the gas stream to said glycol regenerator for heating, and means for discharging the dried glycol from said regenerator and recycle same for further drying of said gas stream;
• the improvement enabling control of emissions of volatile organic compounds which have been absorbed by the glycol during contact with said gas stream and which are vented with said steam, while minimizing the organic contaminants in the water streams produced;
• comprising:
• a cooling condenser means including in series an air-cooled condenser and a downstream water-cooled condenser;
• means for flowing the vented steam and gaseous volatile organics from the glycol regenerator as an input to said cooling condenser means to produce a condenser water stream having a relatively high content of said organic compounds;
• a cooling tower having means for establishing a flow of stripping air;
• means for passing said condenser water stream as an input to said cooling tower, and thence through said tower in counter-current or cross-current relation to said stripping air, whereby said condenser water stream is stripped of substantial parts of its organics content and emerges from said cooling tower as a stripped water stream having relatively low content of said organics;
• and
• means for recirculating at least part of said stripped water stream as a coolant for said water-cooled condenser.