Tubes cleaning

Individual tubes replaceable Tube cleaning hy chemicals inside and Yes Only those in outside rowf Yes Yes Yes Yes... 

Small-tube 10-8 Chemical resistance of tubes Clean fluids, condensing. Low heat transfer ... 

Note System must be free of air leaks steam must be dry and condenser tubes clean. 

Shell-and-tube condensers can be installed with the axis vertical and will be one-pass, the water falling to an outlet tank below. This arrangement permits tube cleaning while the plant is operating. 

When silica levels increase, hydroxide alkalinity measurements become increasingly important to ensure maximum silica solubilization and the reduction of risk of silica deposition. This is especially so for coil boilers because, more than any other boiler type, the use of hydroxide is critical in keeping the waterside surface of the coiled tube clean and deposit free. 

Metal cleaning wastes result from cleaning compounds, rinse waters, or any other waterborne residues derived from cleaning any metal process equipment, including, but not limited to, boiler tube cleaning, boiler fireside cleaning, and air preheater cleaning. 

Important Use phosphate-free test tubes (cleaned with hot diluted HCl) or plastic disposables. 

The atomization temperature is usually chosen so as to give a rapid peak. It should not be so hot as to damage the tube unnecessarily or distil off involatile contaminants, or so cool as to lose sensitivity or create memory effects (although a tube clean, i.e. a high-temperature cycle, can be included in the programme). 

The simple Vycor reaction tube used for the high-temperature reaction is shown in Fig. 1. It consists of a wide body of 30 mm outside diameter and 100 mm length and of a narrow neck of 9 mm outer diameter and 180 mm length. For handling outside of the drybox, it is equipped with a vacuum hose and a stopcock. Prior to use, it should be flamed out under a dynamic vacuum. To keep the neck of the reaction tube clean, the tube should be filled using a funnel with a narrow neck of 180 mm length. 

Someah. K. On-Line Tube Cleaning The Basics," Chew. Eng. Progress. 39 (July 1992). 

Thrust the dispenser into a can of fruit paste and suck up paste to the scratch mark on the glass tube. Then wipe the glass tube with afacial tissue, insert it into a 25 x 150-mm test tube, and blow out the paste onto the bottom of the receiver. Wash the dispenser tube clean with water and leave it upright to drain for the next user. 

If there is a considerable amount of residue in the Claisen flask a third fraction is distilled, using the same precautions as before. Finally, when the distillation is completed, the capillary is removed at once and cleaned by placing it carefully in a test tube containing 5 ml of acetone. Insert a piece of clean glass tubing in the rubber tube and draw the acetone a few times upwards to about the middle of the tube. Clean the Claisen flask according to the usual procedure. Hand the distillate to the instructor with the note book and report. 

Use Thermal oxidation of silicon and fumace-tube cleaning. 

An emerging newer boiler design is to follow the tail water-tube-walled combustion chamber by a long superheater, boiler convection section and economizer. This is called the dacha boiler (after the female dashund dog) because of its extended horizontal configuration with several flyash hoppers. This permits tube cleaning by mechanical rapping and eases the labor of tube replacement when needed. 

The basic heat-transfer surface is a bank of 1 to 20 (but usually 3 to 12) rows of high-tinned tubes. The fluids enter the tubes by box headers (pipe headers at higher pressures), with the tubes welded into one wall of the header internal dividers are used in the headers to create multiple tube passes. The header cover may be bolted to the header, or the header may be welded, with threaded plugs opposite the tube ends to facilitate assembly and tube cleaning. The tubes are slanted downward toward the exit (about 1/4 in. per ft) to facilitate drainage. Occasionally, especially for turbine steam condensation, an A-frame configuration is employed, with the tubes slanted about 30° from the vertical and the fans mounted in forced draft at the base of the A, thereby reducing the plan area required. 

Scale. Some solutions deposit scale on the heating surface. The overall coefficient then steadily diminishes, until the evaporator must be shut down and the tubes cleaned. When the scale is hard and insoluble, the cleaning is difficult and... 

Lange, A., 1990, Money saving by the improved operation of condenser tube cleaning systems, the installation of cooling water debris filters and newly developed condenser monitoring. VGB-Kraftwerkstechnik., 8, 1 - 8. 

FIGURE 15.12. The mechanical tube cleaning action (courtesy of Conco Systems Inc.)... 

Eimer, K., 1985, Recommendations for the optimum cleaning frequency of the Taprogge tube cleaning system. Technical Report 85 - 26, Taprogge Gesellschaft mbH, Wetter. 

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