Heat integration of bioethanol production

The goal of the project is to study how the production facility can be designed optimally depending on outer conditions such as the location of the facility and price level on byproducts.

Experiences from earlier studies has shown that an effective use of energy flows and byproducts is necessary  to make bioethanol facilities competitive. This means that the internal processes has to be energy integrated and that the facility itself is integrated with surrounding combined heat and power plants and/or industries.

Energy integration with surrounding industries

External energy integration with surrounding combined heat and power plants has been studied synoptically before, but few studies have been done on the internal processes. An energy integration of the internal processes means that the energy demand can be decreased by recycling heat, either through more efficient heat exchanging or adaption of the pressures in the process. Through pinch analysis the lowest theoretical steam demand can be found.

The external integration is dependent on the temperature levels on the steam that is needed in the production of ethanol, but also on the waste heat that this generated in the production. This creates questions on whether the waste heat should be used internally or if it should be used for district heating.

The project looks at how the integration differs between different production methods and in what situations the different processes are most suitable. The study will mainly look at the hydrolyze methods using dilute acids or enzymes. Which process that can be considered most suitable depends on what industries or combined heat and power plants that are located nearby as well as the expected price on raw material and byproducts.

Raw material

The study will mainly look at the use of rejected tops and branches and sorted waste as main raw material, but also other raw materials will be studied. Existing plants in Sweden produce ethanol from grain or lignocellulose, which makes this study special in choice of raw material.

Modeling tools

The process will be modeled in Aspen so that different process solutions can be tested. The different production processes will be compared to find the optimal process solutions at different surrounding conditions, e.g. heat and power plants and industries.

Funding

Swedish Energy Agency
Sparbankstiftelsen Sjuhärad
Industripartners

Time schedule

2009.04.01 - 2010.09.30

Project partners

University of Borås
Chalmers University of Technology
Sekab E-Technology
Profu
Borås Energi & Miljö
Åmål municipality

SP Technical Research Institute of Sweden, Box 857, SE-501 15 Borås Phone +46 10-516 50 00, E-mail info@sp.se