Sour Gas Compressors Oil & Natural Gas Applications

Transcription

1 Sour Gas Compressors Oil & Natural Gas Applications Model NFT391 two-stage compressor Solutions beyond products...

2 Vertical Reciprocating Gas Compressors Corken s reciprocating gas compressors are utilized in the completion and production phases of an oil well. Vapor recovery and casing gas removal are common applications. When a well is not connected to a pipeline, the extracted crude oil is temporarily stored in a tank battery at the well site. During this time, the natural gas within crude oil will build vapor pressure. To prevent the vapor from emitting to the atmosphere, a reciprocating gas compressor is used to recover and distribute to a gas gathering system. In a casing gas application, casing head gas collects in the annular space between the tubing and casing dramatically reducing the flow of the well. Our reciprocating gas compressors are used to reduce the back pressure allowing gas and crude to flow easily into the well bore. 2 When applying a reciprocating gas compressor into an oil and gas application, it is important to know whether it is a sweet or sour crude oil application. Sweet crude contains less than.5% hydrogen sulfide and is friendlier to the environment and the compressor. Our standard off-the-shelf compressor with carbon steel components is acceptable for sweet crude applications. In contrast sour crude has.5% or more hydrogen sulfide and is not friendly to the environment or the compressor. It is necessary to use proper materials of construction on several components to prevent sulfide stress cracking. When choosing a compressor technology, one of the primary factors to consider is the maintenance capability of the user. All compressors will require maintenance, but reciprocating compressors do not generally require special training or equipment in order to maintain them. Corken compressors are simple to understand and maintain. Typical top end repairs can be done in the field in a few hours. This results in minimal down-time and maximum productivity. Materials of Construction Corken NFD/NFT compressors use a number of material substitutions. These are based on NACE (MR-175) recommendations, field experience, and industry standards. In general, carbon steel components have been replaced by stainless steel in order to prevent sulfide stress cracking. As a result, compressor failures will be significantly reduced ensuring the NFD/ NFT series will provide safe operation and long service life. Our material selections were carefully chosen with three things in mind: 1. Safety Less toxic gas released to the atmosphere 2. Economic Relief Reduced maintenance costs, downtime, and compressor overhauls 3. Environmental Protection Significantly reduces leakage of volatile organic compounds (VOCs) Single and Double Distance Pieces Explained A distance piece is what makes any gas compressor unique and separates it from an ordinary air compressor. This is the center section of the compressor that contains the compressor s packing (seals). Corken NFD/NFT compressors use long type distance pieces that provide no rod overtravel from one set of packing to the next. This allows oilfree compression when needed, and provides one (D-style) or two (T-style) chambers that can collect any condensed liquids before they can contaminate the crankcase oil. Additionally, these chambers can be purged to control process gas leakage. Purge systems are often customized for the particular application or operating conditions. Purge gas can be nitrogen, propane, sweet gas, or other suitable gas. A very low purge gas flow rate will generally suffice (see page 8 for a detailed illustration). Cylinder Lubrication Large oilfield compressors always use cylinder lubrication to maximize the life of the piston rings, packing, and valves. These are the primary performance and wearing components of any piston type compressor. In Corken compressors, cylinder lubrication extends the life of these components by a factor of 4 or 5, and provides higher volumetric efficiency. This results in a significant decrease in downtime, lower repair parts cost and labor costs, and more efficient operation. Cylinder lubrication also helps prevents corrosion particularly in sour gas applications. The reduced corrosion minimizes or eliminates the need to replace the heavier iron parts of the compressor like the pistons, cylinders, etc. Cylinder lubrication is generally unavailable in other small gas compressors, but is a recommended option on all Corken NFD/NFT compressors.

3 Features & Benefits 3 lb RF ANSI Flange Color Key: Parts containing MC12 corrosion resistant coating. Upper packing (V-ring) Features: Materials of construction suitable for sour gas Corken s MC12 corrosion resistant coating used on all wetted ductile iron parts Flanged process gas connections (RF ASME 3#) Single (NFD) and double (NFT) distance piece versions available Cylinder lubrication available (recommended) Available with optional crankcase heater Upper distance piece Barrier 1 (purge, pad, or vent) Middle packing (V-ring) Lower distance piece Barrier 2 (purge, pad, or vent) Oil deflector ring Lower packing (V-ring) Adjustable packing screw Benefits: Safety benefits Reduces leakage of toxic H 2 S and health hazards Minimizes failures and leakage of flammable & toxic process gas Less maintenance and fewer site visits means less potential exposure to toxic gas Environmental benefits Helps maintain environmental compliance Reduces greenhouse gas Lower toxic H 2 S emissions Economic benefits Decreased downtime Lower long-term repair/ replacement costs Significantly longer service life Model NFT391 shown above Applications: Wellhead Casing Gas Reduction Vapor Recovery (VRU) Flare Elimination Gas Boosting Gas Gathering Gas Evacuation Gas Blanketing Fuel Gas Boosting Enhanced Oil Recovery 3

4 Performance Curves and Specifications Two-Stage NFD391/NFT391 Performance Curves psig Capacity (MCFD) psig 1 psig 5 psig Suction Pressure (psig) 2 psig 5 psig Horsepower psig 1 psig Suction Pressure (psig) Curves based on Natural Gas, Specific gravity =.7, N = 1.26 All data at maximum RPM or HP Lubricated cylinders Site elevation = 1 ASL (35 m) Specifications NFD391 D-style (double packed) NFT391 T-style (triple packed) Available with a lubricator Viton 1 (standard), PTFE (optional) Standard packing, Vacuum & Purge (optional) Available with optional crankcase heater Extended crankshaft & heavy duty flywheel standard 1 Registered trademark of the DuPont Company. Bore - first stage inches (mm) 4.5 (114.3) Bore - second stage inches (mm) 2.5 (63.5) Stroke inches (mm) 3. (76.2) Speed range RPM Maximum power rating HP (kw) 15 (11) MAWP psig (barg) 6 (41.3) Rod load rating lb (kg) 4 (1814) Maximum temperature rating F ( C) 35 (177) 4

5 Performance Curves and Specifications Single-Stage NFD491/NFT491 Performance Curves 8 3 psig 7 Capacity (MCFD) psig 1 psig 2 psig Suction Pressure (psig) psig 3 psig Horsepower psig 1 psig Suction Pressure (psig) Curves based on Natural Gas, Specific gravity =.7, N = 1.26 All data at maximum RPM or HP Lubricated cylinders Site elevation = 1 asl (35 m) Specifications NFD491 D-style (double packed) NFT491 T-style (triple packed) Available with a lubricator Viton 1 (standard), PTFE (optional) Standard packing, Vacuum & Purge (optional) Available with optional crankcase heater Extended crankshaft & heavy duty flywheel standard 1 Registered trademark of the DuPont Company. Bore - x2 cylinders inches (mm) 4. (11.6) Stroke inches (mm) 3. (76.2) Speed range RPM Maximum power rating HP (kw) 15 (11) MAWP psig (barg) 335 (23.1) Rod load rating lb (kg) 4 (1814) Maximum temperature rating F ( C) 35 (177) 5

6 Outline Dimensions Two-Stage NFT391 with Lubricator Inlet: 1-1/4" 3 lb. RF ANSI Flange Outlet: 1-1/4" 3 lb. RF ANSI Flange Cylinder Oil Drain 1/4" NPT Pressurization Tube For F Packing Only 18-3/4 (476) 4-3/8 (1,25) 35-11/16 (97) 5 Groove Flywheel Lubricator Assembly 5-7/8 (149) 9-3/8 (238) 4-11/16 (119) 4-11/16 (119) 13-7/8 (352) 1/2" Holes (13) 5 (127) 13-3/16 (335) 4-1/8 (15) 27-1/16 (687) 3-1/2 (89) 13-7/8 (352) All dimensions in inches (centimeters) 6

7 Outline Dimensions Single-Stage NFT /8 (143) Inlet: 1-1/4" 3 lb. RF ANSI Flange 5-5/8 (143) Outlet: 1-1/4" 3 lb. RF ANSI Flange 5 Groove Flywheel 39-1/16 (992) 35-5/8 (95) 18-3/4 (476) 5-7/8 (149) 11/16 (18) 4-1/8 (15) 13-3/8 (34) 26-9/16 (675) 5 (127) 4-11/16 (119) All dimensions in inches (centimeters) 1/2" Holes (13) 4-11/16 (119) 7

8 A Distance Piece Purge System is Available for All D- and T-Style Compressors Gas Suction PI PI Gas Discharge Purge gas, process gas leakage, and condensed liquids are returned to the compressor s suction scrubber PI Regulator A Suction Scrubber PI Regulator B Virtually all gas leakage from the crankcase vent is purge gas Gas Entrained Liquid Purge Gas Flow Purge Gas Tank Contact your local distributor for more information. Solutions beyond products... CORKEN, INC. A Unit of IDEX Corporation 385 N.W. 36th St., Oklahoma City, OK U.S.A. Phone (45) FAX (45) Visit our website at us at cocsalesdept@idexcorp.com PRINTED IN THE USA JULY 215