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1 Interconversions
Published in Saeed Sahebdelfar, Maryam Takht Ravanchi, Ashok Kumar Nadda, 1 Chemistry, 2022
Saeed Sahebdelfar, Maryam Takht Ravanchi, Ashok Kumar Nadda
In Degussa BMA (Blausäure-Methan-Ammoniak‚ or HCN methane-ammonia) process for ammo(n)dehydrogenation, heat is provided by passing the gases through externally heated gas-fired ceramic tube bundles. Sintered corundum tubes coated with Pt, Ru or Al layer (∼15 microns thick) are used with a gauze catalyst or monolith (Maxwell, 2004). Model reactor studies showed that a special temperature profile is required within the reactor (Koberstein, 1973). The selectivity is 90%–91% based on CH4 and 83%–84% based on ammonia at 1,300°C. The downstream is similar to the Andrussow process. The advantages of the process are a CO2 -free product and valuable H2 waste gas. Due to high endothermicity, high investment and high maintenance costs for the converter are disadvantages of this process especially in larger scales. It is less important than the Andussow process, although it gives more HCN .
Analogue to Digital and Digital to Analogue Conversion
Published in John C. Morris, Digital Electronics, 2013
The major disadvantage of this type of converter is its speed of operation. The time taken for conversion to take place will depend upon the size of the analogue input. The worst case or longest time will occur for its maximum analogue input signal. For example, a 4 bit A–D converter has a clock frequency of 50 kHz. How long will it take to convert a full-scale analogue input signal?
The Alloys of Iron, Their Physical Nature, and Behavior During Deformation
Published in William L. Roberts, Cold Rolling of Steel, 2017
Today, steel is made in oxygen steelmaking furnaces, open hearth furnaces, electric furnaces, and less frequently nowadays, Bessemer converters. Until recently, all steel produced was cast into ingot molds, but the 1960’s saw the introduction of continuous casters, first for billets and then subsequently for slabs for conversion to hot rolled products.
Two new impedance source network topologies for inverter applications
Published in International Journal of Electronics, 2019
Ahmet Karaarslan, Othman Al-Darraji, Doğan Çalıkoğlu
In this study, the two novel proposed topologies, SL&ZSI and X-SL&ZSI, are combined, one-cell or two-cell switched inductor with ZSI, respectively. These circuits can be extended by adding multiple cells of X-SL&ZSI for further improving the circuit performance. The simulation results are obtained using National Instrument Multisim programs that are applied on both topologies. The BF is increased by SL&ZSI and X-SL&ZSI topologies of 133% and 266% at 0.4 duty cycle, respectively. The stress voltage ratio on the capacitor is decreased up to 58% and 70% respectively, compared with the classical ZSI topology. In addition, the continuous input power is obtained and the start-up inrush current is also eliminated by proposed topologies. The results that are obtained from the simulation and theoretical calculation are matched about 2%. The only disadvantage is increasing cost and size of converters which are not important for special and military applications. Besides, the proposed design can be also applied to other types of impedance source networks, especially for discontinuous input power topologies.
High Frequency Transformer Design and Optimization using Bio-inspired Algorithms
Published in Applied Artificial Intelligence, 2018
Jeyapradha Ravichandran Banumathy, Rajini Veeraraghavalu
Figure 2 shows the basic converter schematic and the associated waveforms of a half-bridge isolated dc–dc converter. The element for energy transfer is the leakage inductance of the transformer. The switches S1 and S2 are turned on with a phase shift of 180° and both experience a voltage stress equal to that of the input voltage, in contrast to twice the input voltage as in push–pull and forward converters (Vinnikov, Jalakas, and Egorov 2008). Also, the magnetization of the isolation transformer is bidirectional and hence there is no need for a demagnetizing circuit. Other advantages of this converter include less primary turns for the same input voltage and power, lesser winding costs, lower proximity effect losses, no danger of transformer saturation, reduced cost, and its ability to be scaled up to higher power levels.
Historical overview on the development of converter steelmaking from Bessemer to modern practices and future outlook
Published in Mineral Processing and Extractive Metallurgy, 2019
The main goal of converter process is to decarburise BF hot metal into low carbon steel. Converting is a batch process but blast furnace is a continuous reactor. Even hot metal tapping can be continuous, as is done in very big BFs today. Thereafter the subsequent hot metal treatments and converting are batch processes. Nowadays a batch or heat is made in 40 min approximately. Why not continuous converting? The idea was awaken in 1960s by several research groups e.g. in France, Australia, U.K., U.S. and Japan (Davies et al. 1967; Rhydderch 1967; Berthet et al. 1971; Eketorp 1971; Goss and Blough 1971; Nakagawa et al. 1971; Worner and Baker 1971). The French process was developed at IRSID research station in 1960–70s (Berthet et al. 1971). The reactor was divided into two compartments, in the first one carbon rich hot metal was fed in and blown with oxygen (Figure 8). Lime was added for slag formation. Then the steel-slag-gas emulsion reached a sill over which it was flowing to the second compartment, a kind of settler or decanting vessel to separate metal from slag. The decanting vessel was equipped with deslagging opening and steel was discharged via a siphon system. The process was successfully tested in pilot scale (10 t/h) and the following advances were reported: Lighter investment costs compared with conventional BOF with the same capacity due to smaller scale in all equipment due to continuous operationFlexible operation with high iron yield, simple maintenanceEasy and continuous recovery of off-gas in continuous operation without breaks under atmosphereEven and high steel quality, good dephosphorisation and end carbon control