Hitachi Zosen Inova BioMethan GmbH (HZIB), the biogas technology subsidiary of Switzerland-headed energy from waste technology providers Hitachi Zosen Inova AG (HZI) has announced that it has been awarded the contract by HAMBURG WASSER to build a biogas upgrading plant to process digester gas from wastewater sludge into biomethane. To be installed at the wastewater treatment plant (WWTP) in the Port of Hamburg, Germany, it poses particular construction challenges due to the maritime environment.
Hamburg’s wastewater treatment plant (WWTP) is already able to cover its entire electricity and heat requirements on a self-sufficient basis, using wastewater sludge and digester gas in addition to wind and solar energy. Surplus electricity and heat are fed into the public grid or supplied to the business premises and workshops of a neighbouring company.
Around 10 percent of the sewage gas is already upgraded to biomethane and fed into the natural gas grid. This share is now to be increased by constructing an additional treatment installation on the Köhlbrandhöft site, the contract of which was awarded to Hitachi Zosen Inova BioMethan (HZIB).
Expertise to meet challenging requirements
According to HZIB, the project poses particular challenges in terms of corrosion protection, as the gas treatment plant will have to contend with the salty air, the high air humidity and the brackish water of a maritime environment. Added to this is the “challenging composition” of the sewage gas from the wastewater sludge digesters.
HZIB scored highly on a number of counts in the public tender and convinced the client, Hamburger Wasserwerke GmbH (HAMBURG WASSER), to opt for a technology based on the pressureless amine scrubbing with flexible upgrading capacity.
HZIB says that this was a key consideration when it comes to building an economically efficient plant while dealing with the project’s nominal volumetric gas flow rate that fluctuates between 600 and 1 500 Nm³/h. Another factor is the physical proximity of the project partners, which will facilitate rapid project delivery and quick response times for on-site work.
The contract, the value of which has not been disclosed, covers a gas transportation skid comprising pressure rise and cooling, a condensate shaft, activated carbon filters for the removal of H2S and volatile organic compounds (VOC’s), foundations, the amine scrubbing upgrading unit with a capacity of up to 1 500 Nm³/h of raw gas, and an adsorption drying unit.
The project started earlier this summer with assembly scheduled to be completed by mid-April 2019 and the project to be completed two months later. The biomethane produced will be fed into the local natural gas grid and will be available for households as well as for industrial facilities.