The Energy Return on Investment for Algal Biocrude: Results for a Research Production Facility

This study is an experimental determination of the energy return on investment (EROI) for algal biocrude production at a research facility at the University of Texas at Austin (UT). During the period of this assessment, algae were grown at several cultivation scales and processed using centrifugation for harvesting, electromechanical cell lysing, and a microporous hollow fiber membrane contactor for lipid separation. The separated algal lipids represent a biocrude product that could be refined into fuel and the post-extraction biomass could be converted to methane. To determine the EROI, a second-order analysis was conducted, which includes direct and indirect energy flows, but does not include energy expenses associated with capital investments. The EROI for the production process evaluated here was significantly less than 1, however, the majority of the energy consumption resulted from non-optimized growth conditions. While the experimental results do not represent an expected typical case EROI for algal fuels, the approach and end-to-end experimental determination of the different inputs and outputs provides a useful outline of the important parameters to consider in such an analysis. The Experimental Case results are the first known experimental energy balance for an integrated algal biocrude production facility, and as such, are expected to be helpful for setting research and development priorities. In addition to the Experimental Case (based on direct measurements), three analytical cases were considered in this work: (1) a Reduced (Inputs) Case, (2) a Highly Productive Case, and (3) a Literature Model. The Reduced (Inputs) Case and the Highly Productive Case speculate the energy use for a similar system in an improved, commercial-scale production setting. The Literature Model is populated with relevant data that have previously been reported in the literature. For the Experimental Case, Reduced Case, Highly Productive Case, and Literature Model, the estimated second-order EROI was 9.2 x 10(-4), 0.074, 0.22, and 0.35, respectively. These results were dominated by growth inputs (96%, 89%, 87%, and 61% of the total energy requirement, respectively). Furthermore, the EROI was adjusted using quality factors that were calculated according to the price of each input, yielding a quality-adjusted EROI that parallels a partial financial return on investment analysis. For the Experimental Case, the Reduced Case, and the Highly Productive Case, the quality-adjusted EROI was 9.2 x 10(-5), 0.013, and 0.36, respectively

TLC screening of thraustochytrid strains for squalene production

Screenings of thraustochytrids (Labyrinthulomycetes) have been conducted for 176 strains isolated from various sites in the Asian region to investigate what type of species and strains accumulate high levels of squalene. Thin layer chromatography (TLC) screening for squalene production revealed that 38 strains were rated as "+" (high), 29 as "±" (medium), and 109 as "-" (low). Further, high performance liquid chromatography analysis strongly supported the TLC screening results. Besides the 18W-13a strain of Aurantiochytrium sp., which was previously recognized as a squalene-rich strain, several strains produced squalene at approximately 1 g L-1 of culture volume. Squalene production was strongly related to locality, colony color, and phylogenetic clade. Most strains with "+" squalene spots were isolated from Okinawa, a subtropical region of Japan, while the strains with "±" and "-" squalene spots were isolated from wide geographical regions from tropical to subarctic. Approximately half the strains with orange colonies on GTY medium plates produced a high amount of squalene, whereas the other strains with different colors showed less or no squalene spots on TLC. All the squalene-rich strains were assigned to the Aurantiochytrium clade. Overall, our results suggest that (1) the thraustochytrids show tendentious locality in terms of squalene production, (2) a relationship exists between the metabolic synthesis of carotenoid pigments and squalene production, and (3) the Aurantiochytrium clade may have evolved to accumulate squalene

Rapid growth of charged particle multiplicity in high energy e+e- annihilations

Hadron production by e+e- annihilation has been studied for c.m. energies W between 13 and 31.6 GeV. As a function of 1n W the charged particle multiplicity grows faster at high energy than at lower energies. This is correlated with a rise in the plateau of the rapidity distribution. The cross section sdσ/dx is found to scale within ±30% for x > 0.2 and 5 ≤ W ≤ 31.6 GeV. © 1980

Evidence for planar events in e⁺e^- annihilation at high energies

Hadron jets produced in e+e- annihilation between 13 GeV and 31.6 GeV in c.m. at PETRA are analyzed. The transverse momentum of the jets is found to increase strongly with c.m. energy. The broadening of the jets is not uniform in azimuthal angle around the quark direction but tends to yield planar events with large and growing transverse momenta in the plane and smaller transverse momenta normal to the plane. The simple qq collinear jet picture is ruled out. The observation of planar events shows that there are three basic particles in the final state. Indeed, several events with three well-separated jets of hadrons are observed at the highest energies. This occurs naturally when the outgoing quark radiates a hard noncollinear gluon, i.e., e+e- → qqg with the quarks and the gluons fragmenting into hadrons with limited transverse momenta. © 1979

High p<inf>T</inf> hadron production in photon-photon collisions

We have studied the properties of hadron production in photon-photon scattering with tagged photons at the e+e- storage ring PETRA. A tail in the pT distribution of particles consistent with pT-4 has been observed. We show that this tail cannot be due to the hadronic part of the photon. Selected events with high pT particles are found to be consistent with a two-jet structure as expected from a point-like coupling of the photons to quarks. The lowest-order cross section predicted for γγ → qq, σ = 3 Σ eq4 · σγγ → μμ, is approached from above by the data at large transverse momenta. © 1981