Boiler Elements Research Articles

High temperature corrosion of power boiler components cladded with nickel alloys

Incineration of biomass, waste and sorted rubbish in industrial boilers results in the formation of very aggressive chlorides and sulfur dioxides in off-gases. Harmful action of those substances and dusts in off-gases requires appropriate protection of certain boiler elements, such as heat exchanger pipes and the combustion chamber, against corrosion and erosion. The paper presents the results of attempts to perform pad welding of heat exchanger pipes with nickel alloys Inconel 625 and Inconel 686, and high-temperature resistance tests of the padded welds in an atmosphere of N 2 + 9% O 2 + 0.08% SO 2 + 0.15%HCl for 750 h. Corrosion processes induce the formation of a Cr 2O 3 oxide film of 5–10 μm thickness on the Inconel padded welds, which constitutes a passivation layer, reducing the corrosion rate. The presence of iron on the padded weld surface is conducive to the formation of Fe 3O 4 oxide, which worsens the padded welds' resistance to corrosion and erosion. It has been found that the pad welding technology developed and the padded weld properties of Inconel 625 and 686 comply with the requirements of standards and users, and therefore, it can be used for pad welding of components of boilers for waste utilization and biomass incineration.

Boiler Safety Improvement For Safety ControlsUtilizing Flow Measurement For Input

This paper describes a very interesting industrial safety problem and its solutions. Currently, boiler safety controls utilize pressure drop across various boiler elements in an attempt to guarantee adequate combustion air flow, purge air flow, and atomizing media flow. This paper describes various practical situations where these flow measurements are inadequate. Various alternative measures are described to mitigate the problems presented. The paper should serve as a basis for complete re-thinking on these safety controls on both power, industrial, and commercial boilers.

Hydraulic reliability in parallel elements subject to nonstationary operating regimes in straight-through boilers

Development of hydraulic irregularities is examined in the steam-generating parallel elements of straight-through boilers. Factors determining the potential for a crisis reduction in flow rate to the heating surfaces are established for nonstationary regimes.

Design of boilers with catalytic fluidised bed and their connection to heat supply system

The new advantage of catalytic boiler consisting of the location of heat source near the consumer is described. It imposes some restrictions on the design of such a boiler, which is based on the zonal arrangement approach. The details of such design of boilers with catalytic fluidised bed intended for different purposes (water heating, steam generation, steam superheating) are considered and, in particular, for the boiler with heat capacity 2MW. The description of all main boiler elements is given. There are also the details of working of the autonomous catalytic boiler with fluidised bed in the system of heat and hot water supply.

MARINE BOILER FURNACE DIMENSIONS—A STANDARDIZATION APPROACH

SUMMARYA method is proposed for the standardization of marine boiler furnace dimensions particularly of the vertical superheater distributing header type. With standardization of the furnace dimensions the remaining boiler element could, in turn, be subject to similar standardization which produces a cheaper boiler that can be delivered in a shorter period besides reducing the problem of the spare parts required.In this paper a brief account is given of the different types of marine boilers in use. The requirements for furnace dimensions are next discussed and finally the furnace standardization approach is explained followed by a brief account of the problem of superheater slagging as affecting marine boiler furnace design.