Transfer lines

The vacuum in the mass spectrometer also influences the retention times of the molecules. The gas is drawn in under the effect of depression (see Section 2.2.3 covering the effects of low pressure). 

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With a typical ablated particle size of about 1 -pm diameter, the efficiency of transport of the ablated material is normally about 50% most of the lost material is deposited on contact with cold surfaces or by gravitational deposition. From a practical viewpoint, this deposition may require frequent cleaning of the ablation cell, transfer lines, and plasma torch. 

Corrosion of reactors used for functionalization and ia pipes and valves along transferlines for sulfuric acid is a problem that results ia maintenance shutdowns. Sufficient agitation is needed to keep the resia beads fluidized duting sulfonation. As for copolymer kettles, transfer lines should be sufficiently large to allow reasonably rapid transfer of Hquids and resia slurries. 

Another big advance in the appHcation of ms in biotechnology was the development of atmospheric pressure ionization (API) techniques. There are three variants of API sources, a heated nebulizer plus a corona discharge for ionization (APCl) (51), electrospray (ESI) (52), and ion spray (53). In the APCl interface, the Ic eluent is converted into droplets by pneumatic nebulization, and then a sheath gas sweeps the droplets through a heated tube that vaporizes the solvent and analyte. The corona discharge ionizes solvent molecules, which protonate the analyte. Ions transfer into the mass spectrometer through a transfer line which is cryopumped, to keep a reasonable source pressure. 

Methacrylic acid polymer is iasoluble ia the monomer, which may result ia the plugging of transfer lines and vent systems. Polymers of the lower alkyl esters are often soluble ia the parent monomer and may be detected by an iacrease ia solution viscosity. Alternatively, dilution with a nonsolvent for the polymer such as methanol results ia the formation of haze and can be used as a diagnostic tool for determining presence of polymer. 

In designing faciUties for handling and processing nitromethane, it is recommended that nitromethane not be processed in high pressure equipment. AH vessels for nitromethane service should be protected to prevent adiabatic compression. Detonation traps should be installed at each end of transfer lines and in every 61 m (200 feet) of continuous line. Nitromethane lines should be located underground or in channels wherever possible. Pressure rehef devices (rated - 690 kPa = 100 psig) should be installed between closed valves (81). 

Economy of time and resources dictate using the smallest sized faciHty possible to assure that projected larger scale performance is within tolerable levels of risk and uncertainty. Minimum sizes of such laboratory and pilot units often are set by operabiHty factors not directly involving internal reactor features. These include feed and product transfer line diameters, inventory control in feed and product separation systems, and preheat and temperature maintenance requirements. Most of these extraneous factors favor large units. Large industrial plants can be operated with high service factors for years, whereas it is not unusual for pilot units to operate at sustained conditions for only days or even hours. 

Feedstocks. Feedstocks are viscous aromatic hydrocarbons consisting of branched polynuclear aromatics with smaller quantities of paraffins and unsaturates. Preferred feedstocks are high in aromaticity, free of coke and other gritty materials, and contain low concentrations of asphaltenes, sulfur, and alkah metals. Other limitations are the quantities available on a long-term basis, uniformity, ease of transportation, and cost. The abiUty to handle such oils in tanks, pumps, transfer lines, and spray nozzles are also primary requirements. 

Thus the ECCU always operates in complete heat balance at any desired hydrocarbon feed rate and reactor temperature this heat balance is achieved in units such as the one shown in Eigure 1 by varying the catalyst circulation rate. Catalyst flow is controlled by a sHde valve located in the catalyst transfer line from the regenerator to the reactor and in the catalyst return line from the reactor to the regenerator. In some older style units of the Exxon Model IV-type, where catalyst flow is controlled by pressure balance between the reactor and regenerator, the heat-balance control is more often achieved by changing the temperature of the hydrocarbon feed entering the riser. 

In the modern unit design, the main vessel elevations and catalyst transfer lines are typically set to achieve optimum pressure differentials because the process favors high regenerator pressure, to enhance power recovery from the flue gas and coke-burning kinetics, and low reactor pressure to enhance product yields and selectivities. 

Carbon steel, low-alloy steels Transfer lines, beat exchanger shells, baffles, pump components, heat exchanger tubing, fan blades and shrouds, valves, screens, fasteners... 

Figure 6.9 Irregular deposit and corrosion-product mounds containing concentrations of sulfate-reducing bacteria on the internal surface of a 316 stainless steel transfer line carrying a starch-clay mixture used to coat paper material. Attack only occurred along incompletely closed weld seams, with many perforations. Note the heat tint, partially obscured by the deposit mounds, along the circumferential weld.

Material released Blow (purge) system, clean lines, before breaking when transfer lines the connection are disconnected., Minimize use of hoses AGA XK0775 CCPS G-22 CCPS G-29 FMEC 1997... 

Pressurization due Stop transfer and de-pressurize before breaking to plugged transfer line and clearing plug lines. CCPS G-22 CCPS G-29... 

From the regenerator, the regenerated eatalyst flows down a transfer line eommonly referred to as a standpipe. A standpipe provides the neeessary pressure head needed to eireulate the eatalyst around the... 

For hydrogen reformer transfer lines, materials used are Incoloy 800, HK, and HT cast stainless steels. Wrought 300 series stainless steels and internally insulated carbon, carbon-V2, Mo. and IV4 Cr- /2 Mo steels. Reported failures of transfer lines indicate that failures are associated with... 

Where is naphthenic acid corrosion found Naphthenic acid corrosion occurs primarily in crude and vacuum distillation units, and less frequently in thermal and catalytic cracking operations. It usually occurs in furnace coils, transfer lines, vacuum columns and their overhead condensers, sidestream coolers, and pumps. 

Erosion. The abrasive is likely to be gas borne (as in catalytic cracking units), liquid borne (as in abrasive slurries), or gravity pulled (as in catalyst transfer lines). Because of the association of velocity and kinetic energy, the severity of erosion may increase as some power (usually up to the 3d) of the velocity. The angle of impingement also influences severity. At supersonic speeds, even water droplets can be seriously erosive. There is some evidence that the response of resisting metals is influenced by whether they are ductile or brittle. Probably most abrasion involved with hydrocarbon processing is of the erosive type. 

Identification by labels, numbers, colour coding etc. of vessels, transfer lines and valves. 

Glowing embers, brands Drying equipment Molten metal or glass Heat transfer salt Hot oil/salt transfer lines... 

Hardness Calcium and magnesium salts in the forms of CaCOj, Ca, Mg. This is the primary source of scaling in heat exchange equipment, boilers, pipelines/transfer lines, etc. Tends to form curds with soap and interferes with dyeing applications as well. 

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