TCR technology: CO2-neutral energy sources from biogenic waste

Fraunhofer TCR technology can be used to convert a broad spectrum of biogenic residual and waste materials into storable energy sources. These products are the starting point for, next-generation synthetic fuels or basic materials for the chemical industry.

»Crude« Oil from the TCR process
© Fraunhofer UMSICHT
The CO2-neutral oil from the Fraunhofer TCR process can be processed into standard-compliant fuels

Liquid energy sources and raw materials from fossil sources currently still account for approximately 98 percent of the driving energy in transport and 22 percent of heating energy in Germany. In addition, 16 percent of the mineral oil is consumed in the chemical industry. Several sectors of the economy will continue to depend on liquid energy sources with a high energy density or mineral oil equivalent raw materials in the future, including air traffic, shipping, heavy road haulage and the chemical industry.

Mineral oil equivalents from biomass

Fuels and chemical feedstocks based on biomass can play an important complementary role in these applications to reduce GHG emissions. Especially if they are produced from biogenic waste materials, so that their production does not compete with food production and a plate vs. tank discussion can be avoided. The EU Commission aims to phase out the use of conventional biofuels (»biodiesel«) for the period after 2020 and sets a minimum target for advanced biofuels in transport. [EU Directive 2015/1513]

New process improves oil quality

Biomass combustion, gasification and conversion generally have to contend with restrictions regarding the range of possible input materials, compliance with emission standards and overall energy efficiency. The quality of the products obtained from biogenic residues has also been unsatisfactory to date. Against this background, the Fraunhofer Institute UMSICHT in Sulzbach-Rosenberg has developed a new process for the utilization of biomass residues within the framework of the Center for Energy Storage, which was funded by the Bavarian Ministry of Economic Affairs at the Fraunhofer sites in Sulzbach-Rosenberg and Straubing with more than €16 million: thermocatalytic reforming.

Technology: thermo-catalytic reforming

© Fraunhofer UMSICHT
The TCR process converts biogenic feedstock into oil, synthesis gas and carbonate.
TCR plant
TCR pilot plant at Fraunhofer UMSICHT in Sulzbach-Rosenberg
© Fraunhofer UMSICHT
Technical center hall for the TO-SYN-FUEL project in the Hohenburg market, Amberg-Sulzbach district.

In »thermo-catalytic reforming« (TCR® process), residual biomass is converted into synthesis gas, carbonate and liquid bio crude oil, which forms the starting material for synthetic fuels.

In a first stage, the biomass is gently broken down into biochar and volatile components in a continuously operating screw reactor in the absence of oxygen at medium temperatures (< 500 °Celsius). The formation of tar and other pollutants is prevented by optimized process conditions in the various reactor zones.

Second stage: In a post-reformer, the coal and vapors are catalytically refined further at temperatures of up to 700 °Celsius to improve gas yield and product quality. The vapors are then cooled. During condensation, oil and process water are separated. The remaining gas is cleaned.

Three products: oil, gas, coal

 Synthesis gas, a dust-free product gas with a very high hydrogen content, which can be up to 50 percent.
 Carbonisate (»biochar«) with a high carbon content, which is used in-situ as a catalyst in the TCR process itself, can serve as a soil conditioner or can be stored.
 A pyrolysis oil with a petroleum-like consistency, which has a high calorific value and very low acid values (comparable to vegetable oils). It can either be refined together with mineral crude oil in refineries (co-processing) or further processed into products such as petrol and diesel.

The new development and optimisation of downstream process routes for mineral oil substitutes, e.g. pyrolysis oils, synthesis gases, halogenated hydrocarbons or Fischer-Tropsch products, plays a major role here.

Climate-neutral crude oil

The resulting products are climate-neutral. The energy required is generated from the residues used, so there are hardly any CO2 emissions in the process. The input materials themselves, by definition, have no »CO2 rucksack« (unlike biomass, which also has a small proportion of CO2 emissions due to cultivation).

The coal can be introduced into soils as long as the feedstock is not contaminated. The carbon contained in the coal is then permanently removed from the atmosphere. (The coal from the TCR process is extremely stable due to the low oxygen and hydrogen contents and is not decomposed in the soil). If the carbon is sequestered in this way, the products, i.e. the oil and gas, get a negative CO2 balance.  

In the case of fuel production, the hydrogen required from the feedstock is also provided by the synthesis gas. This means that the fuels produced by the TCR process also have an almost neutral CO2 balance.

Functional principle of TCR technology

Animation of the functional principle of the TCR process

Benefits of the TCR® process

TCR technology stands out from other pyrolysis processes due to its high energy efficiency, a wide range of input materials and, above all, high product quality.

The heat required to operate the plant is generated from the residual biomass. Alternatively, surplus electricity can be used for this purpose. The gas can be used on site in a combined heat and power plant to generate electricity and heat or for the synthesis of fuels. The oil can be used in the mixture as a storable fuel. The biochar can be gasified or used for soil improvement.

Wide range of applications for waste materials

The TCR process works with a broad spectrum of biomasses and residues with a dry content of 70 percent or more, e.g. sewage sludge, fermentation residues from biogas plants, wood residues, landscape conservation material, industrial biomass residues such as spent grains or sludge from paper recycling, biowaste fractions, straw and other agricultural residues up to animal excrements.

Robust process with high energy efficiency

The process ensures high operational stability by preventing dust and tar formation and can process feedstock with moisture levels of up to 30 percent. At the same time, it provides heat for pre-drying biomass with a moisture content of over 50 percent. About 75 percent of the energy from the calorific value of the feedstock is used in the products. If the heat provided for biomass drying is taken into account, around 90 percent of the energy used is available for sustainable use. The containerised plant design allows decentralised plant sizes to be realised in an economically viable way from as little as 300 kWel.

Large-scale plant

There are currently several TCR pilot plants of different sizes: in Chile, Switzerland, Italy and Canada, there are plants with a processing capacity of two kilograms of sewage sludge per hour. 30 kilograms per hour are processed in Birmingham, in Sulzbach-Rosenberg and in future in Edmonton. In Hohenburg (district of Amberg-Sulzbach), a large-scale demonstration plant with a capacity of 500 kilograms per hour was built as part of the EU project »TO-SYN-FUEL«. It processes dried sewage sludge as a feedstock. 

Mobile plant design

The TCR technology was developed for a containerized, compact plant design. The technology thus represents a decentralised solution for the recycling of biogenic residues of various kinds all over the world.

© Fraunhofer UMSICHT
Flexibility on site due to mobile, compact plant design
© Fraunhofer UMSICHT
TCR systems have already been used in Switzerland, Italy, Chile, UK and Canada.
© Fraunhofer UMSICHT
Depending on the region of the world, different biogenic residues are produced. The TCR platform is adaptable for different input materials.