Heating is one of the main energy consuming processes in countries with moderate temperatures. Heat is mostly produced from fossil fuels such as natural gas and fuel oil. A sustainable alternative energy source is biomass. However, combustion of biomass results in harmful emissions to the environment, such as emission of SO2, CO, NOx, fine particles and Polycyclic Aromatic Hydrocarbons (PAHs). Moreover, the remaining ashes cannot be reused. Biological wood oxidation has been proposed as a new technology for heat production at temperatures around 40-55 °C.
Wood oxidation, or aerobic wood oxidation, is a process in which wood is composted by microorganisms in the presence of oxygen. In this process, sustainable heat is produced. Compared to wood combustion, only CO2 and H2O are released to the atmosphere (see the following equation). Besides, the residue from this process is peat instead of ash. Peat soil is rich in organic matters and can be used as fertilizer.
CH1.5O0.7 + 1.03O2 → CO2 + 0.734H20 + Heat
The central challenge is to increase the rate of biological wood degradation. This rate is determined by, for example, types of microorganisms, types of wood, and wood size. Other factors, such as the nutrient supply (i.e. N, P, K), moisture content, temperature and aeration will also influence heat production.
Besides, the assessment of heat production from wood oxidation is unknown.
The main challenges are:
(1) To optimize the temperature, moisture content, aeration strategy, and nutrient
(2) To study the heat production for different types of woods, different wood sizes
(3) To study the suitability of the wood residues as soil improver
(4) To operate a scale-up reactor for heat recovery from wood
(5) To assess the application of heat production from wood oxidation to urban heating system
Key words: wood oxidation; heat production; urban heating system
Fan, S., Li, A., Ter Heijne, A., Buisman, C. J., & Chen, W. S. (2020). Urine Addition as a Nutrient Source for Biological Wood Oxidation at 40 C. ACS Sustainable Chemistry & Engineering, 8(46), 17079-17087.
Fan, S., Sun, Y., Ter Heijne, A., Chen, W. S., & Buisman, C. J. (2020). Effect of nitrogen, phosphorus and pH on biological wood oxidation at 42° C. Science of the Total Environment, 726, 138569.