方法
物料平衡与通量计算采用基于回收率的标准形式（Qp = Qf·Y），净驱动压力由进水压力减去浓水侧压降与该段膜壳侧对数平均渗透压得出。
一价与二价盐透过率分别相对膜元件的台架测试基准条件进行温度与通量归一化处理，体现纳滤区别于反渗透均一脱盐率的选择性脱除特性。
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工程工具 · 膜与过滤
NF 纳滤系统设计工具
对纳滤系统的物料平衡进行建模，独立追踪一价（盐分）与二价（硬度）离子脱除率，支持最多3段配置，并内置求解器反算达到目标成品硬度所需的旁通掺混流量。
ATLAS WTS · Process Engineering
NF System Designer
Nanofiltration mass-balance with selective monovalent/divalent (hardness) rejection tracking, up to 3-stage arrays, membrane-aging projection, and product-water blending — including a solver for the bypass flow needed to hit a target finished hardness.
Project Information
Feed Water & Application
Pressure & Membrane Configuration
2- and 3-stage arrays feed each stage from the prior stage's concentrate, raising overall system recovery beyond what a single stage can reach — standard for hitting the 80-90% system recoveries common in NF softening.
Stage 1
ΔP guidance: ~0.2–0.3 bar (~3–4 psi) friction loss per element in series, ≈1.2–2.4 bar for a standard 6–8-element vessel — independent of how many vessels feed this stage in parallel.
Stage 2 Optional
ΔP guidance: ~0.2–0.3 bar/element in series, ≈1.2–2.4 bar for a standard 6–8-element vessel.
Re-pressurizes Stage 1's concentrate before it enters Stage 2, independent of the main feed pump — useful when this stage would otherwise run short on net driving pressure, especially at high recovery or aged-membrane conditions.
Stage 3 Optional
ΔP guidance: ~0.2–0.3 bar/element in series, ≈1.2–2.4 bar for a standard 6–8-element vessel.
Re-pressurizes Stage 2's concentrate before it enters Stage 3, independent of the main feed pump.
Membrane Aging Projection
Defaults follow the selected application type; edit for a specific project. The "Aged" condition (toggle top-right) projects permeate TDS/hardness and required feed pressure at end of the stated membrane age — both monovalent and divalent passage increase by the same compounding rate.
Product Water Blending (Bypass)
Raw/pretreated water blended directly into the final product stream — the standard NF softening lever for hitting a target finished hardness economically without over-designing rejection. Leave flow at 0 to disable.
Solve for Target Finished Hardness
Back-solves the bypass flow (at current membrane-train performance, using the on-screen Day-1/Aged condition) needed to blend the membrane permeate up to a target finished hardness. Only valid for a target strictly between the membrane's own permeate hardness and the raw feed hardness.
Overall System (Membrane Train + Blend)
Final Product Flow
—m³/h
Final Product TDS
—ppm
Final Product Hardness
—mg/L
Overall Hardness Removal
—%
Overall System Recovery
—%
of total raw intake incl. bypass
Waste (To Drain)
—m³/h
Membrane Train Performance
Train Recovery
—%
Total Permeate Flow
—m³/h
Final Concentrate Flow
—m³/h
Permeate TDS
—ppm
Permeate Hardness
—mg/L
Concentrate TDS
—ppm
Concentrate Hardness
—mg/L
Monovalent (TDS) Rejection
—%
Divalent (Hardness) Rejection
—%
Total Membrane Area
—m²
System Average Flux
—LMH
Stage-by-Stage Breakdown
| Stage | Elements | Recovery | NDP | Osmotic P. | Flux | Mono. Rej. | Div. Rej. | Perm. Flow | Perm. TDS | Perm. Hardness | Conc. TDS | Conc. Hardness |
|---|
Membrane Chemistry Reference (Informational)
Technical Warnings
No warnings — all parameters within the modeled envelope.
Inputs changed — click Calculate to refresh results above.
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此工程工具目前仅提供英文版本。
01
工程依据
标准 / 参考依据
假设
- 单级或多级阵列使用现有的 4、8 和 16 英寸元件尺寸选项。
- 初始/老化工况和旁路混合仍属于现有计算器模型。
范围 / 限制
- 仅采用厂家中立的松散型/致密型纳滤膜分类；选择性脱除建模、膜老化与旁通掺混针对井水、地表水与结垢控制软化工况标定。
02
工程路径
应用
- 回用、淡化与 ZLD 回收、浓缩与零液体排放逻辑。
场景
- 海水淡化与浓盐水管理 通过能量回收和浓盐水价值化实现可持续海水淡化。
- 通用工艺零排放 通过热法-膜法混合系统实现全水回收和废物最小化。