Jet Cooker — Cationic Starch Cooking

Starch is a critical functional chemical in paper making — used as a wet-end additive and surface size. Raw starch slurry (typically 3–8% concentration) must be fully cooked and gelatinised before use. A Primetech jet cooker injects high-pressure steam directly into the starch slurry stream, raising the temperature from 25–40°C to 95–140°C within milliseconds. The turbulent mixing ensures complete and uniform gelatinisation, eliminating raw starch granules that would otherwise cause retention problems on the paper machine.

Unlike jacketed heat exchangers, the jet cooker has no fouling surfaces. The starch does not deposit on hot walls, reducing cleaning downtime and improving availability. Steam usage is near-100% efficient since all latent heat is transferred directly to the slurry.

White Water & Process Water Heating

Paper machine white water (recovered from the wire and press sections) needs to be maintained at process temperature — typically 50–65°C — for efficient drainage and formation. DSI heaters inject low-pressure steam into the recirculating white water loop, providing rapid and controllable temperature recovery. The system responds quickly to load changes caused by grade changes or machine speed variations, maintaining stable headbox temperature within ±0.5°C.

Broke & Pulp Slurry Heating

Broke pulp (recovered paper rejects) is re-pulped and reintroduced into the furnish. The slurry needs to be heated to maintain process consistency and prevent drainage problems. DSI systems tolerate fibrous, abrasive slurries without erosion issues. The open-jet design avoids plug formation, which is a common failure mode with shell-and-tube exchangers handling high-consistency pulp.