Wilco Compressed Natural Gas Vessels

The 48-inch inside diameter, 33.5-cf spherical CNG storage vessel is for the commercial dispensing of compressed natural gas to motor vehicles at CNG fuel stations. The vessel can supply CNG at up to 5,500 psi to a fill-up nozzle.

The vessel assembly is custom designed for the end users, and is designed using the specifications and requirements from ASME Section VIII, Division 2, for National Board registration.

With relief and control valves installed, the unit is 85.2 in (2.165 m) tall with 54.5 inch (1.382 m) outside diameter. The empty assembly weighs 7,910-lb and 8,445-lb fully loaded with CNG.

The pressure vessel design employs a 3.250 inch (82.55 mm) thick spherical shell, and specially designed 1/2, 3/4 and 1-inch NPT couplings. The pressure relief valve nozzle has the same design as the other nozzles, except it has 3/4-inch NPT thread.

The vessel has a conventional skirt type support structure.

A drain line with a high pressure needle valve is located at the bottom of the vessel for easy maintenance cleanout.

An optionally provided high pressure "lock out" valve can be used to close off the vessel's relief nozzle during scheduled maintenance operations. This valve's use in design and practice are prescribed in ASME Section VIII, Division 2.

The vessel is designed for maximum allowable working pressure of 5,500 psi, at 120° F and a minimum design metal temperature of 0° F at 5,500 psi. Analysis of cyclic pressure loadings between 5,500 and 3,500 psi yields a vessel life of 40 years, which exceeds the ISO 11439 requirement of 20-years. The design also incorporates strength requirements for wind and seismic loads.

The 20-inch outside diameter, cylindrical CNG storage vessels are for the commercial dispensing of compressed natural gas to motor vehicles at CNG fuel stations. The vessels can supply CNG at up to 5,000 psi to a fill-up nozzle. Typical commercial systems supply CNG to the customer vehicles’ fuel tanks at ~3,500 to 3,000 psi.

The vessel assembly is custom designed for the end users, and is designed using the specifications and requirements from ASME Section VIII, Division 2, for National Board registration, non on-board unit.

The vessels overall length may be customer specified up to 24-ft. long. The footprint width is 42-inches (1.067 m). The height of the unit, with 3 vessels oriented horizontally and stacked vertically, one on top of the next, is 85 inches (2.159 m) tall.

The empty 24-ft. 3-tank assembly weighs 31,225-lbs. and 32,630-lbs. fully loaded with CNG.

The pressure vessel design employs a thick walled cylindrical shell, and specially designed 1/2, 3/4 and 1-inch NPT couplings. The pressure relief valve nozzle has the same design as the other nozzles, except it has 3/4-inch NPT thread.

The vessel has a saddle-type support structure, designed to allow stacking of the vessels in a variety of fashions.

A drain line with a high pressure needle valve is located at the bottom of each vessel for easy maintenance cleanout.

An optionally provided high pressure “lock out” valve can be used to close off the vessel’s relief nozzle during scheduled maintenance operations. This valve’s use in design and practice are prescribed in ASME Section VIII, Division 2.

SPECIFICATIONS

• Capacity: three (3) 12-ft. vessels is 16,437-SCF at 5,000 psi.

• Capacity: three (3) 24-ft. vessels is 33,840-SCF at 5,000 psi.

• Maximum allowable working pressure of 5,000 psi, at 120° F.

• Minimum design metal temperature of -20° F at 5,000 psi.

• Analysis of cyclic pressure loadings between 5,000 and 3,500 psi yields
a vessel life in excess of 109 years.

• Design also incorporates strength requirements for maximum wind & seismic loads.