Innovative Wellhead Products for Landfill Gas Management

Transcription

1 Innovative Wellhead Products for Landfill Gas Management QED Environmental Systems Inc. Ann Arbor, Michigan - San Leandro, California Copyright QED Environmental Systems, Inc. 2013; all rights reserved. The information contained within this document may not be published, broadcast, rewritten or otherwise distributed without the prior written authorization from QED.

2 LFG Well Field Management Goals Maximize LFG energy content (flow rate and methane concentration) where gas is utilized Avoid NSPS violations for PTO exceedance Comply with LFG emission regulations Avoid odor complaints from neighbors Reduce time and labor spent for well field management Reduce and simplify well field maintenance and repairs Maximize gas collection efficiency while maintaining regulatory compliance, all at the lowest possible cost

3 Traditional LFG Wellhead Designs PVC gate valve for flow control is most commonly used low cost, widely available Union orifice plate, Pitot tube or venturi used for flow measurement (calculated from differential pressure) Flexible rubber couplings used for connections to the well riser and wellhead

4 Problems with Traditional Wellheads Gate valves were designed for controlling liquids, not for regulating gas flow small adjustments in valve opening can result in large changes in applied vacuum and resultant flow, often resulting in over-pulling on the well and air leaks into the landfill and the gas system Field techs can t determine valve position, so recording changes in valve settings is reduced to counting valve turns highly subjective, not truly reproducible Gas flow measurement can be highly inaccurate - pitot tubes, venturis and orifice plates all have accuracy limitations or can be difficult to use, resulting in flow measurement and reporting errors

5 Flow Control Using Gate Valves Advantages Lower initial cost Widely available Disadvantages Closed Non-rising stem - operator can t observe valve opening position Plastic threads can strip easily, plastic handle breaks off with age Seals fail, dirt and grit get into threads and gate track, and extreme cold and heat all make valve difficult or impossible to adjust or cause the valve stem to break when excessive force is applied Fully open in 3-4 turns out of 10 - flow adjustment isn t linear and can be difficult to regulate, especially at low flow rates Open

6 Precision Fine Tune Control Valve Patented flow-tuned valve design provides precise, linear control of flow from fully closed to maximum flow Rising stem design and highly visible metered scale allows observation of valve position setting, making it easy to quickly return to the exact setting if the valve must be closed Rugged stainless steel valve stem and handle make it more durable in harsh outdoor environments.

7 Precision Fine Tune Control Valve

8 QED Precision Valve vs. PVC Gate Valve PVC gate valve offers very little flow control, especially at lower flow rates, with maximum flow achieved at just four turns QED Precision Valve has nearly linear flow control across entire range of valve opening, with unparalleled control at flows under 20 CFM

9 Case Study South Texas Landfill Well 54 The QED Precision Fine-Tune Valve eliminated wide swings in methane concentration and air leaks into the well, improving the overall gas quality while avoiding NSPS violations

10 The Value of Better Flow Control Improved Gas Heat Content Additional Annual Gas 1% Methane Increase Gas Value ($/mmbtu) 1 CFM 5 CFM 10 CFM 25 CFM 50 CFM 100 CFM $1.50 $8 $40 $80 $200 $400 $800 $2.00 $11 $55 $110 $275 $550 $1,100 $2.50 $13 $65 $130 $325 $650 $1,300 $3.00 $16 $80 $160 $400 $800 $1,600 $3.50 $18 $90 $180 $450 $900 $1,800 $4.00 $21 $105 $210 $525 $1,050 $2,100 As little as a 1% increase in methane concentration at a gas value of $2.00/mmBtu in a 50 CFM well can pay for a QED Precision Wellhead and Stabilizer Well Cap in just one year Try the latest QED LFG Calculator at

11 Common LFG Flow Measurement Methods Pitot Tubes are intended to fit a wide range of flow rates, but can easily clog with condensate, mineralization and corrosion, and have poor accuracy at flows under 20 CFM (± 5-10% at best, ± 20% worst) Venturis are also a one size fits all device, but create significant pressure drop at high flows (>12 SCFM) and insufficient pressure drop for reliable measurement at flows under 25 SCFM Orifice Plate sizes can be selected to match changes in flow rates, but changing plates can be time consuming, requires shutting off gas flow and breaking pipe connections, and gas techs can t see the plate size without opening the pipe union

12 Quick-Change Orifice Plate Utilizes proven orifice plate technology for accurate and repeatable flow rates Plates can be swapped out by one person in seconds to achieve desired P with changes in gas flow rate No time wasted shutting down the control valve, breaking pipe connections or rebalancing the well Accessible plate housing allows for easy confirmation of plate size and placement reducing reporting errors Durable PVC construction with stainless steel orifice plates

13 Quick-Change Orifice Plate Quick-Change Orifice Plate can be changed in less than 60 seconds by one person without interrupting LFG flow, saving as much as 1-2 labor hours over traditional union orifice plates

14 Problems with Traditional Well Caps Flexible coupling stacks and donuts tend to leak air into gas system and leachate from foaming wells Couplings aren t very strong, so wellheads lean and wobble Liquid level measurement requires cap removal, shuts down gas flow, and exposes operator to LFG emissions

15 QED Stabilizer Well Caps First engineered LFG well cap that aligns and stabilizes the wellhead, minimizing air leaks and gas release Unique support ring molded directly into the cap (patent pending) takes the side load off Fernco and flex hose Watertight threads help reduce leachate leaks from the wellhead Minimizes air leaks into the gas system, greatly reducing the cost of gas treatment for gas-to-energy and high-btu LFG projects

16 QED Stabilizer Well Caps Easy liquid level measurement without removing the well cap or shutting off gas flow faster, safer, cleaner, easier Ports to accommodate pump fittings for dewatering applications and dedicated bubbler line or Easy Level indicator Caps are molded in high-visibility bright yellow, helping identify and protect the entire well from damage Durable, heavy-walled polyethylene construction makes it ideal for any climate Fits 6 and 8 wells with 2 or 3 LFG wellheads

17 QED Precision LFG Wellhead Designs All featuring the Precision Fine-Tune Control Valve Handle Lateral Handle Vertical Vertical with Quick-Change Orifice Plate System Horizontal with Quick-Change Orifice Plate System

18 Quick-Change Orifice Plate Wellhead Revolutionary Quick-Change orifice plate system for accurate flow measurement at any flow rate Precision Fine-Tune Valve for precise flow control over a broad flow range Emphasis on increasing the visibility of the wellhead includes diamond reflector tape and bright yellow labeling and wing-nut handle

19 Quick-Change Orifice Plate Wellheads Available in 2 and 3 pipe sizes for flows up to 300 CFM Brass barbs or quick-connects for flow measurement and LFG sampling Orifice plate kits contain a range of plate sizes to match flow range of valve

20 Wellhead System Drawings

21 Free QED Wellhead Trial Offer Try a QED Precision Wellhead for 60 days at no charge At the end of the Trial Offer you may purchase the unit or return it to QED

22 Questions? QED Environmental Systems, Inc. Ann Arbor, MI and San Leandro, CA Toll-free: Direct: Fax: