Impact of stream impurities on compressor power requirements for CO2 pipeline transportation

The economic viability of Carbon Capture and Sequestration (CCS) as a means of mitigating CO2 emissions is significantly dependent on the minimisation of costs associated with the compression and transportation of the captured CO2. This paper describes the development and application of a rigorous thermodynamic model to compute and compare power requirements for various multistage compression strategies for CO2 streams containing typical impurities originating from various capture technologies associated with industrial and power emission sectors. The compression options examined include conventional multistage integrally geared centrifugal compressors, supersonic shockwave compressors and multistage compression combined with subcritical liquefaction and pumping. The study shows that for all the compression options examined, the compression power reduces with the increase in the purity of the CO2 stream, while the inter-stage cooling duty is predicted to be significantly higher than the compression power demand. For CO2 streams carrying less than 5% impurities, multistage compression combined with liquefaction and subsequent pumping from ca 62 bar pressure can offer higher efficiency than conventional gas-phase compression. In the case of a raw/dehumidified oxy-fuel CO2 stream of ca 85% purity, subcritical liquefaction at 62 bar pressure is shown to increase the cooling duty by ca 50% as compared to pure CO2

First Cryo-scanning electron microscopy images and X-Ray microanalyses of mucoromycotinian fine root endophytes in vascular plants

Aims: Arbuscule-producing fine root endophytes (FRE) (previously incorrectly Glomus tenue) were recently placed within subphylum Mucoromycotina; the first report of arbuscules outside subphylum Glomeromycotina. Here, we aimed to estimate nutrient concentrations in plant and fungal structures of FRE and to test the utility of cryo-scanning electron microscopy (cryoSEM) for studying these fungi. Methods: We used replicated cryoSEM and X-ray microanalysis of heavily colonized roots of Trifolium subterraneum. Results: Intercellular hyphae and hyphae in developed arbuscules were consistently very thin; 1.35 ± 0.03 μm and 0.99 ± 0.03 μm in diameter, respectively (mean ± SE). Several intercellular hyphae were often adjacent to each other forming “hyphal ropes.” Developed arbuscules showed higher phosphorus concentrations than senesced arbuscules and non-colonized structures. Senesced arbuscules showed greatly elevated concentrations of calcium and magnesium. Conclusion: While uniformly thin hyphae and hyphal ropes are distinct features of FRE, the morphology of fully developed arbuscules, elevated phosphorus in fungal structures, and accumulation of calcium with loss of structural integrity in senesced arbuscules are similar to glomeromycotinian fungi. Thus, we provide evidence that FRE may respond to similar host-plant signals or that the host plant may employ a similar mechanism of association with FRE and AMF

Globular structures in roots accumulate phosphorus to extremely high concentrations following phosphorus addition

Crops with improved uptake of fertilizer phosphorus (P) would reduce P losses and confer environmental benefits. We examined how P-sufficient 6-week-old soil-grown Trifolium subterraneum plants, and 2-week-old seedlings in solution culture, accumulated P in roots after inorganic P (Pi) addition. In contrast to our expectation that vacuoles would accumulate excess P, after 7 days, X-ray microanalysis showed that vacuolar [P] remained low (3,000 mmol kg-1 ), potassium, magnesium, and sodium. Similar structures were evident in seedlings, both before and after P addition, with their [P] increasing threefold after P addition. Nuclear magnetic resonance (NMR) spectroscopy showed seedling roots accumulated Pi following P addition, and transmission electron microscopy (TEM) revealed large plastids. For seedlings, we demonstrated that roots differentially expressed genes after P addition using RNAseq mapped to the T. subterraneum reference genome assembly and transcriptome profiles. Among the most up-regulated genes after 4 hr was TSub_g9430.t1, which is similar to plastid envelope Pi transporters (PHT4;1, PHT4;4): expression of vacuolar Pi-transporter homologs did not change. We suggest that subcellular P accumulation in globular structures, which may include plastids, aids cytosolic Pi homeostasis under high-P availability.Megan H. Ryan, Parwinder Kaur, Nazanin K. Nazeri, Peta L. Clode, Gabriel Keeble‐Gagnèr