Os principais objetivos desse trabalho s\u00e3o: \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 1.-Identificar os poss\u00edveis tipos de contrapress\u00e3o, capazes de existirem na descarga ou descarte de v\u00e1lvula de al\u00edvio de press\u00e3o, e que compreendem:\u00a0Contrapress\u00e3o atmosf\u00e9rica;\u00a0Contrapress\u00e3o superimposta (\u201csuperimposed back-pressure\u201d) constante;\u00a0Contrapress\u00e3o superimposta (\u201csuperimposed back-pressure\u201d) vari\u00e1vel;\u00a0Contrapress\u00e3o desenvolvida (\u201cbuilt-up back-pressure\u201d);\u00a0\u00a0Contrapress\u00e3o total.<\/p>\n
2.- Em fun\u00e7\u00e3o do tipo de contrapress\u00e3o, definir os crit\u00e9rios para a sele\u00e7\u00e3o da v\u00e1lvula de al\u00edvio de press\u00e3o mais adequada.<\/p>\n
3. Apresentar um resumo da Norma API STD 520 Sizing, Selection, and Installation of Pressure-relieving Devices in Refineries\u00a0Part I – Sizing and Selection e\u00a0Part II \u2013 Installation sobre as discuss\u00e3o dos efeitos da contrapress\u00e3o superimposta e da contrapress\u00e3o desenvolvida.<\/p>\n