Structural Design and Life Assessment of a Molten Salt Solar Receiver

Abstract

This paper discusses the structural integrity and creep-fatigue life assessment of a commercial size molten salt solar central receiver. The life evaluation is based on criteria that are a modified version of ASME Code Case N-47. These criteria are deemed conservative enough to provide a reasonable level of safety and reliability, and yet not so conservative as to impose severe economic penalties on the receiver. The justification for these criteria and their application to the receiver are discussed in detail.

A review of steady-state thermal and mechanical modelling on tubular solar receivers

“…The fractional damage for each band is then calculated for each fatigue cycle type and creep loading condition by dividing the actual cycles/loads by the allowable, with the linear damage rule then summing together the contributions of all bands to arrive at a damage estimate [143]. Narayanan et al [145] recommends using an interim solar receiver design code from Berman et al [146] to calculate creep-fatigue of a molten salt receiver design, which is effectively a modified version of ASME B&PV Code Case N-47. The interim standard from Ref.…”

Levelized cost of electricity evaluation of liquid sodium receiver designs through a thermal performance, mechanical reliability, and pressure drop analysis

“…Material creep-fatigue damage envelopes are used to determine the reliability of the receiver when both creep and fatigue damage is occurring simultaneously, as is the case here due to a large total operating time, a large number of thermal cycles, high temperatures, and high stresses. Creep damage is found by investigating the von Mises effective stress (σ vM ) (Fork et al, 2012) (Narayanan et al, 1984) of the load controlled stresses. This stress is used to determine the allowable stress to rupture time (t d ) based on the material temperature, and is divided by the total operational time (∆t d ) in order to determine the damage fraction for that creep load condition (q).…”

“…This stress is used to determine the allowable stress to rupture time (t d ) based on the material temperature, and is divided by the total operational time (∆t d ) in order to determine the damage fraction for that creep load condition (q). The effect of stress relaxation is omitted in the evaluation of creep stress, as the stress is not expected to relax significantly between the relatively short thermal cycles that occur in solar receiver operation (Narayanan et al, 1984). The creep damage for each cycle is established by dividing the actual time spent at the elevated creep condition (∆t d ), into the allowable time (t d ).…”

Structural Design Considerations for Tubular Power Tower Receivers Operating at 650°C

“…The fatigue damage is calculated using the strain in the receiver tube. First, the calculated strain is multiplied by 1.1 to approximate the inelastic strain [14]. The equivalent strain is then calculated using Equation 8where the subscripts correspond to the three principal directions, multiplied by a safety factor of 2.0 [15], and then used to calculate the number of allowable cycles.…”