Steam Purification Research Articles

Safety Instrumented Systems to Investigate the System of Instrumentation and Process Control on the Steam Purification System

This paper explains the SIS to investigate the system of instrumentation and process control on the steam purification systems in the geothermal power plant. The research objectives include (i) analysis based on SIL against the BPCS, (ii) determining the component specifications of SIS, (iii) the design of SIS in the form of drawing, and (iv) simulation aided the application of PLC Simulator against the design of SIS result. Analysis step based on SIL conducted on the existence of BPCS. There are two potential danger of SIL-2, namely the condensate water entered the turbine and the steam pressure drop. The component specification is a consideration for the installation of two actuators with a redundant system. The design of SIS in the form of drawing namely the investigating for the instrumentation and process control through the block diagram, so that the function of the SIS as a protection system against personal safety, environmental, and operating facilities, in addition to the publication of the company's reputation. The simulation against the design of development results namely the conditioning of the operation of the emergency valve for drain to the gain of certainty, that the valve is opened when signals from LSH or logic 1 is received and the valve is closed again after signal reception from LSL or logic 0, so the valve can be operated in accordance with logic operation 1 and 0.

Highly aligned arrays of super resilient carbon nanotubes by steam purification

Steam treatment has been applied to our prefabricated highly aligned areas of electrospun carbon nanotube composite nano-fibres, leading to controlled and targeted removal of polymeric and amorphous carbon materials, resulting in areas of highly aligned, highly crystalline, pure nanotubes. Raman analysis shows how the ID to IG intensity ratio was reduced to 0.03, and the radial breathing mode peak intensity, used for nanotube diameter calculation, changes. Therefore, suggesting that some carbon nanotubes are more resistant to steam assisted oxidation, meaning that specific carbon nanotube diameters are preferentially oxidised. The remaining carbon nanotubes have displayed a significant improvement in both quality, with respect to defect density, and in crystallinity, resulting in an increased resistance to oxidation. These steam treated super resilient carbon nanotubes are shown to withstand temperatures of above 900°C under ambient conditions. Applying this purification method to electrospun nano-fibres leads the way for the next generation of composite materials which can be used in high temperature extreme environments.

Rear side passivation of PERC‐type solar cells by wet oxides grown from purified steam

AbstractTo considerably improve the conversion efficiency of industrial solar cells, the effective passivation of the rear surface is a prerequisite. Thermal grown silicon oxides provide an excellent level of surface passivation on lowly doped p‐type surfaces. However, dry thermal oxidation processes require relatively high temperatures (∼1000°C) and, due to the low growth rate, long process times. To decrease both oxidation temperature and process time, the dry oxidation process can be replaced by a wet oxidation. The most common way to introduce high purity water vapor into the oxidation tube is the pyrolytic generation from high purity gases (H2 and O2). A more easy and cost effective option for the supply of water vapor that was applied within this work is the direct purification of steam. The passivation quality of dry and wet oxides, the latter grown from pyrolytic generated water vapor and purified steam was compared within this work. The passivation quality obtained for the wet oxides grown from purified steam was found to be comparable to those oxides grown from pyrolytic generated water vapor. On laser fired contacts (LFC) solar cells conversion efficiencies well above 20% could be achieved independent of the oxide that was applied for the rear side passivation. Copyright © 2010 John Wiley & Sons, Ltd.

Enhanced Sidewall Functionalization of Single-Wall Carbon Nanotubes Using Nitric Acid

When a sample of as-made single-walled carbon nanotubes (SWNTs) is treated with nitric acid, oxidation debris are formed due to the functionalization (mainly carboxylation) of the amorphous carbon present in the sample and a continuous coating along the carbon nanotube walls is created preventing the sidewall functionalization of the SWNTs. This oxidation debris can be easily removed by an aqueous base wash leaving behind a sample with a low degree of functionality. After removal of the amorphous carbon (by steam purification) from a sample of as-made SWNTs, the resulting purified SWNTs are readily carboxylated on the walls by nitric acid treatment. The use of steam for the purification of SWNTs samples allows the removal of the amorphous carbon and graphitic layers coating the metal particles present in the sample without altering the tubular structure of the SWNTs. The exposed metal particles can then be easily removed by an acid wash. Comparison between the steam treatment and molten sodium hydroxide treatment is made.

Steam Purification for the Removal of Graphitic Shells Coating Catalytic Particles and the Shortening of Single‐Walled Carbon Nanotubes

Purification and shortening of single-walled carbon nanotubes (SWNTs) is carried out by treatment with steam. During the steam purification the graphitic shells coating the catalytic metal particles are removed. Consequently, the exposed catalytic particles can be easily dissolved by treatment with hydrochloric acid. No damage to the carbon nanotube tubular structure is observed, even after prolonged treatment with steam. Samples are characterized by HRTEM, TGA, magnetic measurements, Raman spectroscopy, AFM, and XPS.

Purification and Opening of Carbon Nanotubes Using Steam

Purification and opening of carbon nanotubes has been carried out by treatment of as-made single-wall carbon nanotubes (SWNTs) with pure steam at 1 atm pressure. Treated samples have been characterized by high-resolution transmission electron microscopy and IR and Raman spectroscopy. Comparison between the steam purification and the standard nitric acid purification treatment shows that steam is less aggressive toward damage to the tubular nanotube wall structure and forms fewer functional groups.

Investigation of the scale separators of general-purpose evaporators

The authors investigate the efficiency of operation and the hydraulic resistance of scale separators in general purpose evaporators. A diagram illustrates the design of the apparatus and charts present data on the dependence of the purification of steam on the axial and circumferential speed of the steam in the scale separator, on the dependence of entrainment on the speed of the steam in the inlet pipe, and on the dependence of pressure losses on the circumferential speed of the steam.

Use of porous fluorinated plastic filtering materials for the purification of steam

Use of porous fluorinated plastic filtering materials for the purification of steam

Mechanical Purification of Steam Within the Boiler Drum

Abstract The paper is a report of tests run on new high-pressure high-temperature boiler installations to determine a baffle arrangement for the steam drums that would prevent objectionable carry-over during normal operation. The arrangements of three types of baffle are illustrated and the results are given in tables and graphs as conductivity measurements on condensed steam samples taken from eight different points in the drum. The cyclone-separator baffle finally developed will deliver steam containing solids approximating 0.5 ppm with boiler-water concentrations up to 1600 ppm, and will permit a large range of load change and water-level variation.

Closure to “Discussions of ‘Mechanical Purification of Steam Within the Boiler Drum’” (1939, Trans. ASME, 61, pp. 718–720)

Closure to “Discussions of ‘Mechanical Purification of Steam Within the Boiler Drum’” (1939, Trans. ASME, 61, pp. 718–720)