System and method for controlling process fluids in a plant for manufacturing web-like paper material

A plant (10) for manufacturing a web-like paper material starting from a slurry of paper material to be desiccated, the plant (10) comprising:

• a first drying device comprising at least one rotating Yankee cylinder (12), fed by pressurized steam, wherein said slurry of paper material dynamically adheres to the lateral surface of said Yankee cylinder (12);
• a second drying device comprising at least one hood (14, 16) which at least partially surrounds said Yankee cylinder (12), wherein said hood (14, 16) comprises a first half-hood (14) and at least one second half-hood (16) which are both configured to blowing high temperature dry air onto said slurry of paper material wound on the lateral surface of said Yankee cylinder (12), and to suction hot and moist fumes, released by said slurry of paper material, wherein said first half-hood (14) is a wet half-hood arranged at the inlet side of said slurry of paper material on said Yankee cylinder (12), and wherein said second half-hood (16) is a dry half-hood arranged at the outlet side of said slurry of paper material from said Yankee cylinder (12);
• at least one first delivery circuit (18) for feeding said high temperature air to said first half-hood (14);
• at least one second delivery circuit (20) for feeding said high temperature air to said second half-hood (16);
• at least one first return circuit (22) for suctioning said fumes from said first half-hood (14);
• at least one second return circuit (24) for suctioning said fumes from said second half-hood (16);
• a first interface duct (26) for a fluid connection between said first return circuit (22) and said second return circuit (24), wherein along said first interface duct (26) there are installed a first flow regulating device (28), which is configured to allow the fluid to flow unidirectionally from said first interface duct (26) to said first return circuit (22), and a second flow regulating device (30), which is configured to allow the fluid to flow unidirectionally from said first interface duct (26) to said second return circuit (24);
• and
• a second interface duct (32) for a fluid connection between said first return circuit (22) and said second return circuit (24), wherein said second interface duct (32) is arranged upstream of said first interface duct (26) and wherein along said second interface duct (32) there are installed a third flow regulating device (34), which is configured to allow the fluid to flow unidirectionally from said first return circuit (22) to said second interface duct (32), and a fourth flow regulating device (36), which is configured to allow the fluid to flow unidirectionally from said second return circuit (24) to said second interface duct (32), wherein between said first return circuit (22) and said second return circuit (24) there is interposed at least one third interface duct (38), which is independent from said first interface duct (26) and from said second interface duct (32), wherein along said third interface duct (38) there is installed at least one fifth flow regulating device (40), which is configured to allow the fluid to flow bidirectionally between said first return circuit (22) and said second return circuit (24) through said third interface duct (38).