32% - 50% process flow (three effect countercurrent falling film evaporation)
- Categories:Process flow and design
- Time of issue:2020-12-15 09:35:07
On the premise that the raw alkali meets the standard, 50% liquid alkali and 100% are excellent products.
NaOH ≥50% wt
Na2C03 ≤625 ppm wt
NaCI03 ≤40 ppm wt
Fe203 ≤6 ppm wt
NaCI ≤62.5ppm wt
Temperature 45 ° C
0.8MPa raw steam enters the first effect evaporator (e0109) after passing through the steam regulating valve. After heat recovery by two preheaters of first effect section (e0107) and second effect section (e0104), the steam condensate is sent out of the battery limit by its own pressure and can be used as boiler feed water. The secondary steam generated by first effect evaporation is used as the heating medium of second effect evaporator (e0106), and the second effect condensate enters the condensate tank (v0101). The secondary steam generated by Effect II evaporation serves as the heating medium of effect III evaporator (e0103), and the effect III condensate enters the condensate tank (v0101). The secondary steam generated by effect III evaporation condenses in the surface condenser (e0101), the vacuum pump (p0101) sucks negative pressure, and the generated condensate enters the condensate tank (v0101), which is uniformly sent out of the boundary by the condensate pump (p0102).
Process technical scheme
The raw alkali with the concentration of 32% is concentrated to 50% by three-way countercurrent falling film evaporation technology. After cooling, it becomes 50% finished liquid alkali. The raw steam required for heating is 0.8MPa G.
Brief description of process flow
The 32% NaOH solution sent from outside the battery limit is added to the effect III falling film evaporator (e0103), and the concentration is increased from 32% to 36%. After being pressurized by the effect III alkali pump (p0103), the concentrated alkali solution enters the Effect II falling film evaporator (e0106) after being heated by the preheaters of Effect II section I (e0104) and section II (e0105), and the concentration is increased to 42%. After being pressurized by the Effect II alkali pump (p0104), the concentrated alkali solution passes through effect I section I (e0107) and two-stage (e0108) preheaters are heated and enter the I-Effect falling film evaporator (e0109), and the concentration is increased to 50%. The alkali liquor reaching the concentration is pressurized by the I-Effect alkali pump (p0105), cooled to 45L by the I-Effect two-stage (e0108) and two-stage (e0105) preheaters and alkali liquor cooler (e0102) and sent to the finished alkali tank outside the boundary for storage.
1. Circulating water: the low-temperature water from the circulating water system is sent back to the circulating water system for cooling after heat exchange between the surface condenser and the alkali cooler.
2. Condensate: the high-temperature condensate generated by the falling film evaporator is used to preheat the alkali liquor and recover its heat, and the condensate after heat exchange is sent outside the battery limit.
3. The condensate from the surface condenser and the condensate from the falling film evaporators of Effect II and III are returned to the condensate tank and sent by the condensate pump to the outside of the battery limit for use and for the mechanical sealing water of the hemp gland.
1. The process adopts three effect countercurrent falling film evaporation, which is simple, easy to operate and control and stable production;
2. Control system: DCS automatic control system is adopted to realize remote control. Valves with high operation frequency adopt regulating valves; key parameters such as temperature, flow, pressure and current are displayed on the computer screen of DCS operation station and can be used as signal source to control regulating valves; the start and stop of machine record can be controlled by DCs and on-site.
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