The LD2000-6 multi-effect distilled water machine uses a six-stage heat-integrated evaporation and condensation process. It uses secondary steam generated in the previous effect as the heating source for the next effect, progressively purifying feed water and finally producing water for injection that meets pharmacopoeia standards. The rated output is 2000 L/h.
Overall Process Logic
The equipment adopts a counter-current feed multi-effect evaporation mode. Fresh industrial steam is supplied only to the first effect. Secondary steam generated in each effect serves as the heating source for the next effect. Secondary steam from the last effect, the sixth effect, is condensed in a condenser. This allows multi-stage reuse of steam heat and significantly reduces operating energy consumption.
Specific Workflow
Feed and Preheating
Pretreated purified water first enters the preheating coil of the sixth effect, then passes through preheaters from the fifth to the first effect, absorbing residual heat from condensate in each effect step by step. The inlet water temperature rises close to the boiling point of the corresponding effect. The preheated purified water is then delivered to each evaporation chamber by a feed pump, and a forced circulation pump drives high-speed circulation in the heating tubes, improving heat transfer efficiency and reducing scaling.
Preheating coils, heating tube bundles, and connecting flanges must be accurately matched for thermal expansion, corrosion resistance, and dimensional stability. Hansheng Automation can provide precision machining for these components based on customer-provided drawings, including single-piece and small-batch production.
Evaporation and Heat Exchange
Fresh industrial steam at 0.2–0.3 MPa enters the first-effect heating chamber, heating the circulating liquid in the first-effect evaporation chamber. The liquid boils and produces secondary steam. The fresh steam condenses on the outside of the heating tubes and is discharged through a steam trap to recover residual heat.
The secondary steam from the first effect passes through a vapor-liquid separator to remove entrained droplets, then enters the second-effect heating chamber as the heating source. It condenses on the outside of the second-effect heating tubes, while the liquid in the second-effect evaporation chamber is heated and evaporated, producing new secondary steam.
This heat exchange and evaporation process is repeated from the third effect to the sixth effect. Evaporation pressure and liquid boiling point decrease in each effect, ensuring that secondary steam from the previous effect can effectively condense and release heat in the next effect.
To maintain effective vapor-liquid separation and prevent droplet carryover, internal baffles, demister supports, and separator housings often need to be tailored to specific flow rates and pressure conditions. We can machine these non-standard separation components according to customer specifications, helping users maintain stable distillate quality.
Condensate Collection and Sterile Filtration
The secondary steam from the sixth effect can no longer be used as a heating source, so it enters a shell-and-tube condenser and is condensed into distilled water by cooling water. Condensate from each effect heating chamber is collected into a collection tank by gravity or pump. All collected distilled water then passes through a 0.22 μm pyrogen-free sterilizing filter to remove microorganisms and particulates, producing water for injection that meets Chinese Pharmacopoeia and GMP requirements.
In the condensation and filtration stage, non-standard condenser end covers, tube sheets, filter connection fittings, and sterile filter housings are often required during maintenance or capacity adjustments. Hansheng Automation supports drawing-based custom manufacturing to help users maintain system integrity and compatibility without changing the original equipment structure.
Auxiliary Control
The system is equipped with a fully automatic control system that monitors pressure, temperature, liquid level, and product water flow in each effect in real time. It automatically adjusts steam pressure, cooling water flow, and feed volume to ensure stable operation and compliant water quality.
