EnviTec Biogas, Evonik strategic partnership celebrates 5 years

By EnviTec Biogas | December 05, 2017

Following the successful commissioning of 20 EnviThan gas upgrading plants in Germany, U.K., France, China and Denmark, EnviTec also now looks back on a successful five-year partnership with Evonik, the technology leader for membrane-based gas separation. “As Evonik’s very first strategic partner, we are proud to have been a part of gas upgrading with SEPURAN Green from day one, so to speak – something that cannot be taken for granted in today’s market environment,” says Olaf von Lehmden, CEO of EnviTec Biogas AG, which is based in Lohne and Saerbeck, Germany.

First deployed for CO2 separation at EnviTec’s pilot plant in Sachsendorf, the high-selectivity membranes are now well-established on the market—and the partnership with EnviTec has also gone from strength to strength. “Our shared experience over the last few years has generated a number of other successful projects, even outside Europe’s borders,” says Goetz Baumgarten, business director membranes within Evonik’s High Performance Polymers division. “In 2017, EnviTec was once again the leading consumer for our modules in the biogas industry.” The three-stage membrane-based process for efficient gas separation patented by Evonik achieves a membrane yield of over 99 percent and makes the upgrading of biogas to biomethane significantly more cost- and energy-efficient.

The partnership between the two companies began in October 2012 with the commissioning of the first EnviThan plant in Sachsendorf, Brandenburg. By the spring of 2013, two further gas upgrading plants with an output of 350 normal cubic metres had already been commissioned in Sachsendorf and Köckte in Saxony-Anhalt. This was the green light for the commissioning of no less than 20 EnviThan plants, first in Europe and shortly afterwards in Asia, and there’s no end yet in sight—two new plants are now being built in France and Denmark.

“The SEPURAN membranes are made from a high-performance plastic we developed in-house that has excellent pressure and temperature stability,” explains Volker Wehber, director SEPURAN Green in the membranes business segment. “This plastic gives the membranes their ability to distinguish precisely between methane and CO2, so methane can be obtained with a purity level of over 99 percent from the crude gas.” Currently, EnviTec is the only provider that also completes the fitting of Evonik membranes into their pressure housing—“this is also a sign of our perfect teamwork,” says EnviTec gas upgrading specialist Stefan Laumann.

The modular design enables existing plant to be expanded without major structural effort: this option has already been chosen many times by customers and successfully installed by EnviTec. One decisive benefit here is the minimal period of interruption for expansion work. With EnviThan plants, membranes can even be retrofitted with zero downtime for the system.

Over the last five years, this innovative gas upgrading technology has seen a series of improvements. While all of the plants started by feeding biomethane into the existing natural gas grid, three plants are now manufacturing Compressed Natural Gas (bio-CNG) from biogas for the transport sector. “We see this particular application as a key driver in the move to sustainable transport in Germany,” says Stefan Laumann. “While we initially installed the membranes vertically, we ultimately switched over to a new, horizontal arrangement—and this is now the standard membrane design,” says Laumann. By using this horizontal arrangement, EnviTec is now able to install almost three times as many modules in a single container.

“Another change was introducing the option to source the feed-in compressor from EnviTec as well,” says Laumann. This compressor boosts the pressure of the biomethane produced from around 12 bar to the network pressure required by the various destination gas networks. Progress has also been made in developing smaller, more compact plants: EnviTec now offers a single-container model for biogas plants up to 300 Nm³/h. The new container design also provides dedicated space for up to two horizontal membrane racks: this is much more cost-effective, since it not only avoids using a second container but also saves on the pipework, cabling and base.