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Water Treatment
Published in Carl Bozzuto, Boiler Operator's Handbook, 2021
Some plants cannot tolerate the additional dissolved solids that result from sulfite addition. These are primarily nuclear plants, heat recovery steam generators (HRSGs), and super critical (or once-through) boilers. These plants will use all volatile treatment (AVT). This treatment uses hydrazine as the oxygen scavenger. The hydrazine reacts with oxygen to form water and nitrogen gas. The water is desirable. The nitrogen must be removed first in the condenser and then in the deaerator. Hydrazine is hazardous and must be handled with care. Wear that protective clothing.
Chemicals from Non-hydrocarbons
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
Also, because of the weak nitrogen–nitrogen bond, it is used as a polymerization initiator. As a reducing agent, hydrazine is used as an oxygen scavenger for steam boilers. It is also a selective reducing agent for nitro compounds. Hydrazine is a good building block for many chemicals, especially agricultural products, which dominates its use. Hydrazine is also used as a propellant in space vehicles to reduce the concentration of dissolved oxygen in and to control pH of water used in large industrial boilers.
Steam Production and Cooling Tower Water Treatment
Published in Paul N. Cheremisinoff, Handbook of Water and Wastewater Treatment Technology, 2019
In this method, no solid chemicals are added to the boiler or preboiler cycle. As a result, the volatile carryover of solids is eliminated and turbine deposits are avoided. Cycle pH is controlled between 9.0 and 9.5 with a volatile amine such as ammonia. Hydrazine, or a suitable substitute, is added as an oxygen scavenger. With volatile treatment the feedwater must not contain hardness or condenser leak constituents.
Potential effective criteria for selection of polymer in enhanced oil recovery
Published in Petroleum Science and Technology, 2022
Scrutiny is a must while preparing polymer solutions. To avoid any degradation (mechanical), the solutions were prepared with a low degree of agitation. First, distilled water was put on a stirring machine at 400–600 rpm in a 500 ml beaker. Precise control of rpm was maintained, so to avoid any mechanical degradation. Then, using a magnetic stir bar a vortex was created. After the vortex was created the powdered polymer was slowly sparked on the shoulder of the vortex. To prevent excessive air which contains oxygen to be available to the system as it can adversely affect the formation of the polymer solution, the top of the beaker was covered and for that purpose aluminum foil was used. As when more and more polymer was dissolved in water it increased the viscosity of the solution. After 60–120 minutes polymer solution appeared as a homogeneous solution. The solution was stirred for 20 hours to secure full hydration. The solution which contained NaCl (to check the effect of monovalent ions on polymer solution) was stirred for 40 hours. This process was repeated until the polymer became homogeneous. In this study, the temperature was set to 301.5 K and maintained for all the experiments with no addition of biocides or oxygen scavenger.
Atomization gas type, device configuration and storage conditions strongly influence survival of Lactobacillus casei after spray drying
Published in Drying Technology, 2022
Katarina Jokicevic, Sarah Lebeer, Filip Kiekens
The viability of L. casei AMBR2 was examined via the nett effect of different device configurations, i.e., open and closed system, different gas carriers, with and without the presence of ascorbic acid (Figure 2). Interestingly, comparable viability (with 0.5 log reduction in viability) was obtained when cells were dried in an open and closed mode using atmospheric air as a carrier. Contrarily to what we expected, the addition of ascorbic acid (vitamin C) as an oxygen scavenger to reduce and prevent oxidative damage of cells, actually resulted in a significant decrease in CFU counts in both open and closed air-based systems (0.80 and 1 log reduction CFU, respectively). Furthermore, the oxygen depletion by using a 99.5% nitrogen as a gas carrier also resulted in a significantly lower CFU numbers in comparison to the air carrier systems. Vitamin C fortification of the suspensions dried in the nitrogen inert and closed system also did not result in an improved survival, yet in similar outcomes as without any additions, or a 0.85 log reduction.
Evaluation of DNA intercalation study and biological profile of a series of Schiff base metal(II) complexes derived from amino acid
Published in Inorganic and Nano-Metal Chemistry, 2021
Chandrasekar Thiravidamani, Nazia Tarannum
The oxidative cleavage study was performed utilizing (2 µL, 10 µM) pBR322 super coiled plasmid DNA, in buffer (Tris–HCl, 50 mM) with sodium chloride (50 mM, pH 7.2) and dealt with synthesized metal compounds (30 μM) and ascorbic acid (10 M) pursued by reduction in concentration with buffer solution to a final quantity of 20 μL.The incubation of the samples was done for about 1 h at 35 °C. The 25% bromophenol blue was used as loading buffer. The process of oxidative cleavage was executed for 1 h at 40 V in Tris acetate EDTA (TAE) buffer using agrose gel (1%) with 1.0 μg/mL of ethidium bromide. The damage of calf DNA helix was scrutinized by the use of gel electrophoresis process. The agrose gel was envisaged under a UV illuminator by fluorescence of intercalated ethidium bromide. The measurement of the oxidation of calf-DNA was through formative aptitude of the synthesized compounds to change super coiled-DNA (SC-DNA) to linear form and nicked circular (NC) form. The inhibition reaction was conceded by the process of prior incubation of pUC19 DNA with sodium azide (100 μM) (singlet oxygen scavenger) and DMSO (4.0 μL) (hydroxyl radical scavenger).