Two-time Calibration at Both Ends for Sulfur Measurement by Using High Frequency Induction Infrared Absorption Method

High frequency induction heating infrared absorption method is a relative measurement method, and it requires calibrating the analyzer during the measurement process. Usually, one-time calibration on an analyzer is made for high sulfur value by using standard substances. The method proposed by this paper calibrates carbon-sulfur analyzers with a method of two-time calibration at both ends, which eliminates the impact of sulfur blank and thus improves the accuracy and precision of ultra-low sulfur measurement. The method extents the lower limit of measurement of sulfur in high temperature alloy, to 0.00005%, namely, 0.5ppm.

Antioxidant Activity Test of Effervescent Granules Morinda citrifolia L Leaf Extract with DPPH Free Radical Absorption Method

Morinda citrifolia. L leaf is a plant that has the potential as an antioxidant due to the presence of compounds in the form of flavonoids and other phenolic compounds that can function as natural antioxidants. In connection with this, research was carried out to Morinda citrifolia. L formulate leaf extract in the form of effervescent granules. Morinda citrifolia leaf extract was macerated with ethanol 96% as solvent. Phytochemical screening showsthat the extract contains flavonoids, tannins, saponins and alkaloids. The extract was formulated with various concentrations of F1 (20%), F2 (25%), F3 (4%). Determination of antioxidant activity using the DPPH free radical immersion method. The results showed that the concentration in the granules influenced antioxidant activity with IC50 values of 109.05 ppm, 101.33 ppm and 73.28 ppm, respectively

COMPARATIVE ANALYSIS OF THE EFFICIENCY OF WATER AND WATER-AMINE ABSORPTION PROCESSES FOR EXTRACTING CO2 FROM BIOGAS

The production of biomethane from biogas energy costsfor the most widely used amine and water processes for extracting carbon dioxide from biogas were analyzed using computer simulation. Combined water-amine absorption method of biogas purification from CO2 wasincluded in the comparative analysis. For the CO2 content of the biogas from 32 to 42 %, the specific energy costs when using water absorption to extract carbon dioxide from biogas are, on average, in ~ 2.5 times lower than amine absorption, but the loss of CH4 by water absorption was 7.1–7.6 % due to its watersolubility with practically zero CH4 loss when using amine absorption and insignificant loss (0.17–2.8 %) using water-amine technology. Using preliminary water absorption of CO2 saved CH4 can compensate the power consumption of the biogas compressor or the heatcosts of saturated amine absorbent regenerating. This will allowto reduce energy consumption to almost equal to water absorptionone. The results of simulation of carbon dioxide extraction from biogas can be used to optimize technological absorption schemes for the production of biomethane — an analogueof natural gas. Bibl. 13, Fig. 5, Tab. 6.