Page 178 - Advances in bioenergy (2016)

the pipelines.

Steam gasification is advantageous for this process because of the high content of methane in
the product gas, which gives a higher overall efficiency for the process. Agnion uses in the
distributed SNG concept no cold gas cleaning, because of the heat loss. As the heat pipe
reformer is operated at 5 bars, the condensation of the steam in the product gas can be done at
a temperature level, where additional district heat can be provided. In this way the overall
efficiency is quite high, as also the condensation heat of the steam can be used. So the chemical
efficiency from biomass to SNG is up to 70% and the overall efficiency above 90%. 56

A fixed bed methanation process, suitable for decentralized SNG production was studied by
57
Kienberger et al. In this process, catalytic methanation and catalytic tar-reforming was
combined within one reactor. The influence of the gasifier operation parameters (temperature,
residence time, input steam content) on syngas quality and composition was discussed.
Actually the gasification technology of heat pipe reformer is demonstrated only for CHP in
Germany.

Large-Scale FT Synthesis (Choren)

On January 31,1990, UET Umwelt- und Energietech-nik Freiberg GmbH (later the Engineering
division of CHOREN Industries GmbH) was formed. The portfolio included process
technology for steam fluidized bed drying, analysis services for optimizing power plant

equipment and many other energy processes. 58
®
The construction and commissioning of a 1 MWth Carbo-V pilot plant in 1998 marked an
important milestone. The plant's objective was to demonstrate the effectiveness of Carbo-V ®
technology for the production of fuel gas and synthesis gas from carbonaceous feedstocks. The
®
process was then thoroughly tested from 1998 to 2004. The Carbo-V pilot plant was
successfully operated with a wide variety of feedstocks (such as untreated wood, various types
of waste timber, ‘dry stabilate’ material from waste processing, meat and bone meal, hard
®
coal, and lignite). In 2001, a 150-kW gas engine successfully ran under load on Carbo-V gas
®
for 600 h, thus verifying the potential of the Carbo-V process for electrical power production
from biomass.

R&D activities for production of renewable transport fuels began in 2000. A FT test rig for
fuel production was built. In September 2001, a joint research project with DaimlerChrysler
was started with funding from ZIP, an innovation program from the German Federal Ministry
for the Environment. Subsequently, Volkswagen joined the research activities being pursued by
CHOREN and DaimlerChrysler in September 2002. One objective was the physical use of the
®
raw gas from Carbo-V gasification to produce renewable synthetic fuels. A synthesis pilot
plant was thus built, initially for methanol synthesis and later for FT synthesis, as an extension
®
®
of the already existing Carbo-V pilot plant. The Carbo-V pilot plant with FT synthesis was
later named the a-Plant. By the end of 2004, the plant had been operating successfully for more
than 22,500 h.