ONE SOURCE ONE PURPOSE MANY SOLUTIONS Utility Users Group Meeting Orange Beach, AL August 4, 2015 GUIDELINES & TECHNIQUES FOR THE EFFECTIVE CONTROL OF.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
ONE SOURCE ONE PURPOSE MANY SOLUTIONS
Utility Users Group MeetingOrange Beach, AL
August 4, 2015
Steam Surface Condensers: GUIDELINES & TECHNIQUES FOR THE EFFECTIVE CONTROL OF CONDENSATE DISSOLVED OXYGEN
(DO2) IN STEAM SURFACE CONDENSERSPrepared and Presented by
Darren M. NightingaleDirector of Engineering, TEi Condenser Division
GUIDELINES & TECHNIQUES FOR THE EFFECTIVE CONTROL OF CONDENSATE DISSOLVED OXYGEN IN
STEAM SURFACE CONDENSERS:
Low levels of dissolved oxygen in the condensate produced within steam surface condensers, is highly desirable and an increasingly important aspect related to the efficient operation of today’s power plants. The presence of high levels of dissolved oxygen within condensate can quickly contribute to accelerated corrosion & additional treatment requirements as well as increased maintenance and operational challenges. Under certain operating conditions, steam surface condensers can be expected to produce condensate with pre-defined, or guaranteed, levels of dissolved oxygen. However, these levels can only be achieved by a combination of following design guidelines and not exceeding operational limitations - this is not always the case. This 20min presentation includes the latest design guidelines, operational limitations and general considerations, as well as practical techniques, for minimizing dissolved oxygen levels for condensate produced within the condenser.
• HENRY’S LAWBased on Henry's Law formulated by the English chemist William Henry states that at a given temperature, the solubility of a gas is directly proportional to the pressure of the gas directly above the liquid.
• LE CHATELIER’S PRINCIPLELe Chatelier's principle states that a change in any of the factors determining equilibrium will cause the system to adjust to the changes in order to restore equilibrium.
Le Chatelier's principle predicts that the solubility of a gas willincrease as a system loses heat, and will decrease as a system gains heat.
• Steam Surface CondenserNeeds to operate with maximum efficiency to remove as much Dissolved Oxygen as possible, however, this IS limited by Operational Parametrics!
• Most Condensers should not exceed 42ppb under practical operating conditions. [BWR-Nuke, 10-50ppb]
• Condensers can achieve as low as 7ppb and 14ppb given stable operation at the Design conditions (100% Duty!).
• Condensers do NOT perform well when they…• …Operate at LOW LOAD Conditions!• …Cycle or have Transient Operation!• …Have to deal with High Quantities of Make-Up < TSat!!
• 1. Connection (Re)Design Convert Baffles to Spray Pipes! Revised Location to ABOVE Bundle, not side, or below Install a properly designed Spray Pipe (Reheat)
Spray Pipe above vs Baffle on side of Bundle!! Increased Distribution Area & Volume. Improved the Contact/Residence Time. Reheating was vastly improved. Dissolved Oxygen liberated IN Bundle. Dissolved Oxygen removed from Bundle via
Air Draw Off, Vent Duct & Vacuum Equipment Eliminated “Spikes” in DO2 during Make-Up. Reduced DO2 by up to 21 ppb.
• LOW (Transient) LOADS (Reheat).• LOW C.W. Temperatures (Winter).• Simple Control (On/Off).• Popular in Combined Cycle Plants.• And.…Base Loaded Fossil Units that now Cycle!• Auxiliary Steam (typ. 50psiG @ 350°F & 1,200+ Btu/lb)• When to Operate a Hotwell Sparger? V. IMPORTANT!