Photobioreactor estimation

The rate of H2 production by one unit of photobioreactor s volume is not useful for estimation of strain capabilities or for measurements of efficiency of light energy conversion. However, it is useful unit of measurements for optimization of hydrogen production by particular photobioreactor. From practical point of view it does not matter how much cells are in the photobioreactor or how much hydrogen is produced by one unit of illuminated surface. The rate of hydrogen production by the whole photobioreactor is of first importance. For a comparison of different photobioreactors it is better to express rate of hydrogen photoproduction per unit of its volume. So, it is practical unit for estimation of actual hydrogen photoproduction. 

Metis161 reported a preliminary cost study on a 500-L scaled-up modular photobioreactor, and outlined the following cost distribution for the unit based on operating it for a period of 6 months photobioreactor materials, 45% mineral nutrients, 39% labor 4% water supply, 4% land lease, 2% power, 1% and miscellaneous expenses, 5%. He reported the actual cost of the materials for the pilot photobioreactor unit as 0.75 m 2, but the material used and the lifetime of the unit was not stated. This cost is much lower that the often quoted estimates of up to 100 per meter square using glass covered structures. Glass does not appear to be a realistic material to use in a commercial photobioreactor system because of both initial and replacement costs. 

For a stand-alone photobiological (sulfur-deprived, algal) H2-production facility producing 300 kg/day of H2, the total capital investment was estimated to be 5 million with a H2 selling price of approximately 14/kg of hydrogen and a 15% return on investment. This system assumed moderate improvements in the H2-production rate and included PSA purification with high-pressure compressed H2 storage. The total photobioreactor area was 110,000 m with a 10-cm pond depth, 0.2 g/1 cell concentration, and 10/m reactor cost. ... 

In the earlier example, the local production rate was assumed to be known for the purposes of illustration. Nevertheless, as stated in Section 1 (and detailed in Section 5), is a function of the specific rate of photon absorption A. This is why photobioreactor studies require solution of the radiative transfer equation prior to estimation of the production... 

In this section, we present a Monte Carlo algorithm for estimation of the specific photon absorption rate (xq) at any location Xq within any photobioreactor s reaction volume confined by two diffuse-reflective surfaces (7Z and JF) with uniform reflectivity and p, respectively, where T is Lambertian emitting with uniform surface flux density n,i/ is non-... 

Figure 27 Calculation time for estimating the specific rate of photon absorption A within the reaction volume of the DiCoFluV photobioreactor, as a function of the number of light-diffusing optical fibers. The results were obtained in EDStar (Delatorre et al., 2014) by implementation of the algorithm presented in Section 4.1 for different versions of the geometric structure in Fig. 26B (containing different numbers of fibers).

When a Monte Carlo algorithm is used for estimation of any physical quantity B), a simple and fast additional procedure can be implemented that simultaneously estimates sensitivity of B to any parameter (Delatorre et al., 2014). This practically means that when Monte Carlo code is available that computes B, only a few additional lines of code are needed so that partial derivatives of B are also computed with respect to all the parameters ofinter-est. We are interested either in physical analysis (how does B evolve when a parameter is modified ) or in optimal design (what is the optimal value of the parameter for a target value of E ). A general overview of sensitivity estimation is available in Delatorre et al. (2014). This methodology was implemented in Dauchet et al. (2013) and Delatorre et al. (2014) to evaluate sensitivity of the radiation field within a DiCoFluV photobioreactor (see... 

This trend of vs /ph(0) can be better understood by calculating the efficiency of hght use and thus calculating the biomass yield on photons Vx/ph-For this we need the specific photon consumption rate qp. The [Pg.232]

Figure 33 Illustration of the graphical estimation of photobioreactor productivity expressed per of illuminated surface. Graph is based on hypothetical antenna size mutant with cix=1.75 m molx See Fig. 32 for more details.

The increased productivities achievable in photobioreactors versus open ponds were demonstrated by Tredici and Materassi (1992). However, comparison of open pond systans and various photobioreactors for a number of species, including Chlorella pyrenoidosa, Tetraselmis chui and Spirulina spp., made by Lee (2001) showed that productivities from photobioreactors need not surpass those of open pond systems. More recent estimates of productivities (Chisti, 2007 Wiffjels and Barbosa, 2010) suggest that photobioreactors will be essential to achieve the high production necessary for commercial production of bioenergy and other bioproducts. 

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