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PASS/NOZZLE-FEM 3.5. Program Manual | |
In the presence of corrosive hydrogen sulphide environment additionally to stipulations of (5.27-5.22) a strength condition for calculation tensile stresses on the inside surfaces of shell (head) and nozzle shall be fulfilled:
| \[ \sigma_{1in} \le 1.5[\sigma]_{HS}. \] | (5.23) |
Maximum tensile stresses for two-dimensional stress state:
| $$ \sigma_1 = \max{ \left\{ 0; \frac{1}{2} \left( \sigma_\theta+\sigma_x+\sqrt{(\sigma_\theta-\sigma_x)^2+4\tau^2_{\theta x}} \right) \right\} }. $$ | (5.24) |
Allowable stresses in operating conditions in the presence of corrosive hydrogen sulphide environment:
| $$ \sigma_{HS} = \eta\min{ \left\{ \frac{R_e\thinspace\mbox{or}\thinspace R_{p0,2}}{n_y}; \frac{R_m}{n_s} \right\} }. $$ | (5.25) |
Safety factors are assigned by table 5.14, depending on vessel group in operating conditions. Apparatus group is defined as per [16].
| Table 5.14. Safety factors | ||
| Vessel group | ny | ns |
| I | 2 | 3 |
| II | 1.8 | 3 |
| III, IV | 1.6 | 2.6 |
| V | see [12, 16] | |
In the presence of corrosive hydrogen sulphide environment it is assumed to use vessels fabricated of carbon and low alloyed steel, operating under static and recurrent static loads and temperature below 200°N and partial pressure of hydrogen sulphide above 0,0003 MPa [16].
In addition to strength assessment [16], PASS/NOZZLE-FEM performs assessments as per to [12] in accordance with the code requirements [16].
PASS/NOZZLE-FEM 3.5. Program Manual
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