The Blue Tower uses regenerative feedstock for energy production. It produces a clean, CO2-neutral gas, called Blue Gas. The conversion from regenerative feedstock to Blue Gas (reforming) takes place in multiple, separate process steps. That is why the process is also referred to as staged reforming.
1. Decomposition of regenerative feedstock
First, regenerative solid waste (e.g. garden waste, roadside green cuttings, olive stones, or chicken manure) is fed into the Blue Tower. Temperatures of approx. 600°C lead to thermal decomposition of the feedstock (pyrolysis). 80 percent of this feedstock is converted into a gas; 20 percent remains as solid material (coke) which is subsequently used to generate the process heat required by the Blue Tower.
2. Refinement of the gas into Blue Gas
Secondly, at a temperature of approx. 950°C, the gas produced in the first step is refined into a clean, CO2-neutral product gas called Blue Gas by adding steam (reforming). The Blue Gas is very high in hydrogen (approx. 50% hydrogen content) and low in tar. It can be filtered and used in gas motors for electricity generation or it can be processed to pure hydrogen.
3. Provision of process heat
Heat required for thermal decomposition (step 1) and gas refinement (step 2) is provided by heated ceramic beads. These ceramic beads move through the process steps from top to bottom in the Blue Tower in a closed cycle and dissipate their heat step-by-step. The solid material (coke) described above (in step 1) is burned in order to heat up the beads. The processes can run continuously. In doing so, Blue Tower can produce large amounts of Blue Gas, approx. 3,000 m3 per hour. A Blue Tower pilot installation was operated between 2001 and 2006 in Herten, Germany. After the expiration of the permit for this pilot operation, the installation was decommissioned and dismantled. The pilot operation proved the efficiency of Blue Tower technology. During the pilot operation of this first Blue Tower, a number of optimization potentials were identified. These will be realized in a demo installation in Herten, Germany as of 2009. It is the goal of this R&D project to prove the marketability of this technology.
Further information on the Blue Tower: