Study on inversion method of spectrum parameters for slurry in direct absorption reactor

Abstract A direct absorption reactor can increase its temperature by using the internal biogas slurry to absorb and scatter the solar spectrum, where the fermentation process can be well maintained. Therefore, the optical properties of the biogas slurry have direct impact on the solar energy utilization rate of the reactor, which are the basic parameters to be used to simulate the interior photochemical conversion process. Since it is difficult to directly obtain the optical parameters of the biogas slurry with particles, a hierarchical method is proposed in this paper. The absorption coefficient of the biogas slurry without particle is firstly obtained via parameter inversion, and the numerical simulation and experimental comparison are subsequently performed to obtain the scattering coefficient of particles. The results show that the double thickness method can achieve higher calculation accuracy compared with the forward model, especially at weak absorption regions, the calculation accuracy of the optical cavity transmittance can be effectively improved by using strong forward scattering. In the below parameter inversion of the particle scattering coefficient, certain scattering conditions are set for different situations.