Results of a study of tube specimens cut from hot-water boilers show that film-forming octadecyl amine (ODA) used in the process of preservation removes deposition from the surface of the metal. An ODA film is preserved on the surface after repeated washing of the latter with hot water. The concentration of chlorides at the surface of the metal after treatment with ODA is lower than before the treatment.It is known that in the case of long-term standstill (over 7 days) of the power equipment of a cogeneration plant the equipment should be protected from standstill corrosion.The equipment with scale on the surfaces, under the layer of which corrosion processes intensify, requires protection especially urgently. In the presence of moisture standstill corrosion develops even in the absence of scale.Today the metal of power equipment is protected from standstill corrosion by various methods aimed at preventing contact between the metal and air and creating a protective film on the surface of the metal.One such method involves the use of film-forming amines, octadecylamine (ODA) in particular [1 -4]. This reagent forms a protective film on the surface of the metal, which prevents contact between the metal and aggressive media, for example, humid air. In addition, ODA possesses detergent properties [2, 3], which makes it suitable for preservation and washing-off of deposits (here and below we imply loose deposits) from power equipment stopped for a long period. At cogeneration plants this concerns hot-water boilers, which do not operate for virtually half a year.With allowance for the positive experience in the use of ODA for preservation of horizontal delivery preheaters PSG-1, -2 at power units with T-250/300-23.5 turbines, workers of TÉTs-22 of the Mosénergo Company decided to use the reagent for preservation of hot-water boilers PTVM-180. The problem with these boilers was that the deposits grew rapidly not only during service but also during dead time, when delivery water was passed through. It was expected that the use of ODA would not only reduce the corrosion rate of the tubes of hot-water boilers but also wash the surfaces from deposits (scale) for summer standstills of the heating surfaces of the boiler. In addition, the formation of a protective ODA film on the surface decreases the intensity of scale growth during operation and in the period of passage of delivery water. The positive result of preservation and washing at low amounts of deposits (up to 1000 g/m 2 ) was expected to prolong the service life of hot-water boilers and to increase the time of operation of convection bundles. This should prolong the individual lifetime of the boilers with allowance for the standstill time.In 2001 the PTVM-180 hot-water boilers of TÉTs-22 of the Mosénergo Company were preserved in a special way. The layout consisted of a batcher tank for preparing an aqueous emulsion of ODA, an intermediate vessel from which the ODA emulsion was pumped into the bottom headers of waterwall tubes of the hot-water boiler, and a pump fo...

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Results of investigations of the dependence of the percentage of voids on the shear force of a layer of ash, on the basis of which the design principle of the subassembly for the feed of ash to a transport pipeline is developed, are examined for optimization of ash flows in a pulsed regime. The schematic of a system of pulsed pneumatic transport of ash from the bins of ash collectors, and results of measurements during experimental operation of the system, as well as relationships for the calculation of its dynamic parameters are presented. Conclusions concerning the high reliability of the removal and pneumatic transport of ash over a distance of more than 80 m with minimal air consumption are drawn on the basis of results of the experimental operation.Existing systems for the pneumatic transport of ash have either a short time to overhaul and high air consumption, or an appreciable cost. In these systems, pneumatic transport is restricted by the initiation of deposition of a powdery medium in the pipeline. The velocity of the pneumatic transport should therefore be greater than the velocity, as defined by the initiation of deposition. High pneumatic-transport velocities in certain systems (12 -20 m/sec) cause significant abrasive wear of the walls, which excludes use of a transport pipeline with bends.The method developed for the pneumatic transport of ash in a pulsed-piston regime [1] exhibits high operating characteristics and in-service reliability. To optimize the formation of ash flows (piston-induced) in a pulsed regime, we conducted investigations of the dependence of the percentage of voids (porosity) å on the shear force of the layer of ash using a device in the form of a U-tube. The housing of the device is fashioned from D c -50 and D c -80 pipelines. The following operations were performed during the investigation: a covering of a metered batch of ash, a fluidized bed to an established height, a piston device in the bed of ash, the pulsed effect of the weight of the metered mass on the surface of the piston, and measurement of the displacement of an indicator.The fluidization rate and percentage of voids å were calculated in accordance with [2]where d is the average diameter of the ash particles, m; ñ v , ñ t , and ñ o are the densities, respectively, of the layer of ash, dust particles, and air, g/cm 3 ; ì is the viscosity of the air, g/(cm · sec); and g is the acceleration of free fall, m/sec 2 .Results of the investigations (Fig. 1) indicated the identical character of the dependence of å on the displacement Äh 1 of the ash layer as a result of the pulsed action, and on the force F of the pulsed effect on the layer of ash for D c -50 and D c -80 pipes. It is apparent from Fig. 1 that when å = 0.7 -0.55, an additional pulsed effect is required to displace the layer of ash (to consolidate the layer), and a force several times smaller is required to displace the layer of ash after it has been consolidated to å = 0.45 -0.5.Thus, the ash-feed assembly should form an ash bed with a consolidated structu...

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