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xebec psa technology

PSA Technology

Xebec's licensed rotary valve technology replaces the complex and bulky network of piping and valves used in conventional PSA systems with two compact, integrated valves. These rotary valves are included in Xebec’s advanced purification and separation products, and they speed up (or intensify) the rate at which gas can be flowed into a PSA system that uses adsorbent beads in the separation process. In turn, the process intensification allows the PSA to be reduced in size, requiring smaller vessels (compared to conventional PSAs) to purify a particular volume of product gas. In addition, Xebec has a license to structured adsorbent material, which avoids the fluidization limitation of beaded adsorbents. Xebec's licensed structured adsorbent and rotary valve technologies are integrated into some of its advanced hydrogen and biogas purification products, which operate at significantly higher cycle speeds (up to 50 cycles/minute) than conventional PSA systems. This results in a direct reduction in the amount of adsorbent material, the size of equipment and the amount of energy required to purify a given volume of feed gas.

Membrane Technology

Xebec’s Membrane solution is another proven technology for biogas purification. When the product stream must be delivered at higher pressures (typically higher than 250 psig) or for smaller feed flow rates, Xebec offers high-performance, hollow fiber polymer membranes. When pressurized biogas feed enters the membrane modules, CO2 has a much stronger preference to diffuse and permeate through the polymer-based membrane than CH4 molecules. As a result, the product stream, which is rich in CH4, is retained in the pressurized side and can be sent directly to the natural gas grid.

Based on the desired degree of product purity and methane recovery, Xebec employs a two- or three-stage membrane system for biogas upgrading. These advanced membrane separation techniques are superior to market competitors in several ways:

  • The high methane recovery rate (up to 99.8%) generates very small amounts of CH4 (between 0.5- 1%) in the exhaust stream
  • The flexible membrane technology has the ability to produce product gas streams with different methane contents
  • Apart from the high purity product gas, a portion of the recycle stream, which contains about 40% CH4, can be withdrawn and used as a heating and electricity resource within the plant
  • The flow rate of the recycle stream from the multi-stage membrane system is about 30-60% less than that of other available membrane systems. This leads to enormous energy savings in the compressor section of the unit.

Hybrid Technology

Xebec has been designing advanced Helium (He) recovery systems for several years, but has just recently developed a hybrid helium purification and conditioning system that will take low helium concentrations from a gas well, typically 0.6 to 2.5% of helium, and purify the gas stream to 99.999% (5 nines) pure helium, while achieving recovery rates of up to 95+%. After the helium purification step, the product helium gas can be liquefied or compressed for further monetization. Due to the fast cycle PSA technology of Xebec and the utilization of high performance membranes, these helium purification systems have a relatively small footprint and can be deployed in remote areas.

The hybrid system benefits from positive aspects of both PSA and Membrane systems. As an example, the membrane system is only preferred over a PSA system when the operating pressure is higher than 250 psig; however, the hybrid system is able to operate in wide ranges of pressure (100-400 psig).

Filtration Technology

Xebec has been designing and manufacturing air and gas filters for decades. In 2014 Xebec launched a dedicated filter line for natural gas filtration. The high-grade, cast aluminum filter housings (XL and XM series) are chromatized for corrosion protection and finished with an impact and abrasion-proof powder coating on the outer side. High pressure carbon steel housings (XH series) are manufactured by means of iron phosphate passivation and have a nickel-coated finish. This multi-layer surface protection ensures high resistance and a long service life.