Azota’s Cryogenic Plants

Background

In 1983, a small company of gas processing engineers built their first cryogenic high ethane recovery plant. It was a 50 MMSCFD plant located in East Texas and passed its performance test exceeding all guarantees; 92 % ethane recovered at greater than design capacity. That plant is still in operation, unaltered from its original design.

They went on to build many more plants and with each one we tweaked the design to improve performance and operability. In 2006, this group of entrepreneurs founded Azota and are still known for inventive designs and process expertise. We are seen as the midstream contractor with more gas plant process engineering expertise than any in the industry. Our plants are custom designed for each application with attention paid to the details and some of the best recoveries in the industry.

Our Secret Sauce

We are sometimes asked why our plants operate so well, and why they startup so easily.  There are of course many reasons for this. One response we typically give; “compare the area of our brazed aluminum exchangers with any other contractor’s plant of the same size.” The large surface areas which permit closer temperature approaches and better thermodynamic performance are what we call, “the gift that keeps on giving.” And as you visit an Azota plant you will inevitably notice that the towers stand taller than the typical plants due to the extra trays used for improved separation. Heat exchangers, towers, air coolers, compressors; the safety factors of an Azota plant do make a difference.

Our Process Design

There are no substitutes for good process design. One way to validate this is to examine the amount of energy needed to extract a gallon of NGLs. The compression horsepower associated with a cryogenic gas plant is a quick and accurate way of examining the plant efficiency. Azota consistently seeks to minimize compression horsepower, both in the residue compressor and, when present, in the refrigeration compression. 

Effective Modularization

There is art in the fabrication of a modern cryogenic plant. Our modularization techniques are tailored to ease field installation. Not only do we seek to provide a robust and easily operated skid mounted plant, but we take special efforts to ensure that the logical flow of operations from dehydration through product delivery is operator friendly and easily erected. 

The graph below compares a typical recycled reflux demethanizer plant to a single reflux demethanizer plant. Both show the horsepower vs. ethane recovery percentage for typical 200 MMSCFD plants. In order to increase the recovery of a traditional single reflux high ethane recovery plant it is necessary to lower the demethanizer pressure (increase the turbo-expander expansion ratio), which increases the required compression ratio of the residue gas compressors. The recycled refluxed system can achieve equivalent recoveries with less horsepower, or it can reach recovery levels unattainable with the single reflux design.

Azota may be able to retro-fit your older expander plant to a recycled reflux design for a surprisingly low cost.