Process sequence

A thick ( 1 jum) field oxide layer is formed after the implant activation. The field oxide is generally deposited nsing low-pressnre CVD (LPCVD) or plasma-enhanced CVD (PECVD) process becanse the Si-face of SiC has very low oxidation rate and becanse consumption of the implanted layer must be minimized. The field oxide layer is then patterned by selectively etching to remove all oxide from the 

Vertical 500 mA/div Horizontal 500 mV/div Step Gen(A/V) 500 mA/Step Step Offset O.OOA 

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Metallization. Integrated circuits require conductive layers to form electrical connections between contacts on a device, between devices on a chip, between metal layers on a chip, and between chips and higher levels of interconnections needed for packaging the chips. It is critical to the success of IC fabrication that the metallization be stable throughout the process sequence in order to maintain the correct physical and electrical properties of the circuit. It must also be possible to pattern the blanket deposition. 

Fig. 5. Processing sequence for methanol from coal or fuel oil.

Fig. 1. Gel—sihca glass process sequence showing the process steps A, mixing B, casting C, gelation D, aging E, drying F, dehydration or stabilization ...

Process Sequence. The process sequence consists of recovery of tall oil soap from the pulping blackhquor, acidulation, ie, conversion of the soap into CTO with sulfuric acid, fractional distillation to separate rosin, and fatty acids and purification of the fatty acid fraction. 

It is recognized that the wastewater volume and characteristics from a specific industrial category will depend on such factors as plant age, size, raw materials used and in-plant processing sequences. 

Low-molecular-weight products, generally secondary metabolites such as alcohols, carboxyhc and an iino acids, antibiotics, and vitamins, can be recovered using many of the standard operations such as liquid-hquid extraction, adsorption and ion-exchange, described elsewhere in this handbook. Proteins require special attention, however, as they are sufficiently more complex, their function depending on the integrity of a delicate three-dimensional tertiaiy structure that can be disrupted if the protein is not handled correctly. For this reason, this section focuses primarily on protein separations. Cell separations, as a necessary part of the downstrean i processing sequence, are also covered. 

The review should emphasize developing an understanding of the processing sequence, the equipment, the equipment plot, the operating conditions, instrument and sample locations, the control decisions, and the operators perspectives. Wmle the preparation effort may be less for those who have been responsible for the unit for a long period of time, the purpose of the test requires that the types and locations of the measurements be different from those typically recorded and typically used. The condition of these locations must be inspected. Operating specifications may be different. Therefore, refreshment is always necessaiy... 

Process equipment function changes with different steps in process sequence (e.g., same vessel used as feed tank, reactor, crystallizer pump... 

Process equipment function changes with different steps in process sequence (e.g., same vessel used as feed tank, reactor, crystallizer pump used to pump in/out). Instrumentation and controls not kept in phase with the current process step (e.g., control set points, interlocks etc.). 

Can the process sequence be changed to improve the safety of the process ... 

The components produced by the process sequence outlined above are blended as required to meet final product rates and qualities. 

The processing sequence for the production of energetic composites mainly consists of the feed preparation, mix-... 

The success of continuous processing heavily hinges on the speed and continuity of the feed materials into the process. A main problem with the continuous processing of energetic composites is the surging in the solids feed, making the process sequence hazardous and product... 

Distillation, extractive distillation, liquid-liquid extraction and absorption are all techniques used to separate binary and multicomponent mixtures of liquids and vapors. Reference 121 examines approaches to determine optimum process sequences for separating components from a mixture, primarily by distillation. 

Processing sequence The following sequence is typical, although not all stages may be essential. 

For SNG manufacture, it is necessary to reduce the residual hydrogen to a minimum in order to achieve a high calorific value. This is best realized if the synthesis gas, instead of having a stoichiometric composition, contains a surplus of C02 which can be utilized to reduce the H2 content by the C02 methanation reaction to less than 1% according to equilibrium conditions. The surplus C02 must be removed at the end of the process sequence. It is, of course, also possible to operate a methanation plant with synthesis gas of stoichiometric composition then there is no need for a final C02 removal system. The residual H2 content will be higher, and therefore the heating value will be lower (cf. the two long term runs in Table II). 

F. Moeller If you want to realize a catalyst which can hold some ppm s of sulfur, you should realize that you need not just one catalyst. You need a catalyst which does the job at all temperatures. We know of catalysts that can have some sulfur in the feed gas at relatively high temperature levels. That s no problem. But if you go to the low temperatures that you need to get specification SNG so that you can put your gas into your pipeline, then you have a real problem. So if you look for a sulfur-resistant catalyst, it must be resistant over the whole process sequence. Personally, I cannot foresee a catalyst which will work at lof temperature and be insensitive to sulfur. 

Primary waste generation is small because of the high density nature of the fused salt operations. Nearly all primary waste residues show excellent potential for recycle. (The present main processing sequence for plutonium does not include significant reagent and residue recycle). 

This document will summarize our present main production sequence and discuss how it was arrived at. It will then discuss the status of our present recycle of plutonium values in residues. Third, it will discuss our proposed recycle of all plutonium in residues. Finally, it will discuss our goal of a fully integrated process sequence where plutonium and salt residues are recycled through the production sequence. 

Main Process Sequence For Conversion Of Plutonia To High-Purity Metal... 

A. Process Schematic. A schematic of the main process sequence for the conversion of plutonia scrap to high-purity metal is shown in Figure 2. Plutonia scrap is fed to both the direct oxide reduction (DOR) process and the plutonium tetrafluoride production/ reduction process. 

Molten Salt Extraction. The metal from DOR and PuF4 reduction is impure and proceeds to the next step in the process sequence... 

Molten Salt Extraction Salts Plutonium and Americium Recovery. We have demonstrated the ability to successfully strip the plutonium from the MSE salts. The resulting metal product now contains as much as 10% americium and as a result cannot be fed directly into the metal processing sequence. To use the plutonium we must remove the americium. 

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