Petrochemical · Boiler Make-up Water
Shaanxi Yanchang Petroleum Xinghua Chemical 116.7 m³/h × 3 RO Membrane Replacement
All three RO units were re-membraned in one campaign: installation completed in 7 days and commissioning within 10 days. Over 7 days of continuous operation each unit delivered more than 127 m³/h with salt rejection above 99%, resolving the rising permeate conductivity of the old membranes.
PetrochemicalGroundwaterThree Units in ParallelFast Membrane Change-out
>127Permeate per unit m³/h
>99Salt rejection %
7Days to install
3Units
01
Project Overview
Client, scale, feed water and project background
The utility building of Shaanxi Yanchang Petroleum Xinghua Chemical operated three 116.7 m³/h reverse osmosis units whose elements had been in service for three years. Permeate conductivity had been rising steadily and could no longer meet boiler make-up water quality. The owner ran a competitive tender for a full membrane change-out, won by Shaanxi Zhenghe Puye Environmental Technology together with Nexympure products.
Feed water is on-site groundwater, measured at about 800 μS/cm with an operating water temperature of 24–25 °C. The contract was signed on 28 November 2022, work started on site on 18 December, and all three units were fully re-membraned by 25 December, after which they were handed over for trial operation.
From 3 January 2023 the three systems ran continuously for 7 days, with each unit delivering more than 127 m³/h and salt rejection above 99%. The owner confirmed acceptance on the Equipment Operation Acceptance Form and rated both product performance and technical service as qualified.
- Client
- Shaanxi Yanchang Petroleum Xinghua Chemical Co., Ltd. (utility building)
- Location
- Xingping, Shaanxi Province
- Project type
- Full RO membrane element replacement
- System scale
- 116.7 m³/h × 3 units
- Feed water
- On-site groundwater, about 800 μS/cm, 24–25 °C
- Product water use
- Boiler make-up water
- Membrane elements
- QC-LP-8040-400FR
- Acceptance date
- 3 January 2023 (confirmed after 7 days of operation)
02
Process Design
System flow, design boundaries and key control points
01Groundwater
→02Pretreatment (multi-media + UF)
→03Cartridge filter
→04High-pressure pump
05First-pass RO
→06Second-pass RO
→07Demineralized tank
→08Boiler make-up water
The membrane change-out did not alter the existing system framework; the focus was on element selection, loading sequence and inter-stage pressure balance so that all three units would deliver consistent output and rejection under the same feed conditions.
Timing the change-out from the decay curve
After three years of service, permeate conductivity had risen continuously. Comparing normalized permeate flow and salt rejection confirmed that membrane performance had decayed to the point requiring a full replacement, avoiding the trap of a partial change-out that still leaves the system off specification.
Aligning parameters across three units
After replacement, feed pressure and recovery were tuned unit by unit so that output deviations stayed within a narrow band, simplifying load distribution and unified cleaning later on.
Organizing a winter shutdown
Mobilizing in December and completing all three units in 7 days depended on early element delivery, staged isolation and pre-arranged flushing procedures, minimizing plant downtime.
Acceptance based on continuous operating data
Acceptance was organized only after 7 days of continuous operation, covering temperature swings and load changes so that the conclusion would be representative.
03
Key Equipment & Membrane Configuration
Membrane models, loading arrangement and auxiliary equipment
| Item | Configuration / parameters | Notes |
|---|---|---|
| Membrane elements | QC-LP-8040-400FR | Fouling-resistant low-pressure composite membrane |
| Number of units | 3 | 116.7 m³/h each |
| Feed conditions | Groundwater, about 800 μS/cm, 24–25 °C | Measured on site |
| Pretreatment | Multi-media filtration + UF + cartridge filter | Existing system retained |
| Dosing | Reducing agent, antiscalant | Per existing system configuration |
04
Operating & Acceptance Data
Field measurements versus contractual guarantee values
| Assessment item | Acceptance result | Notes |
|---|---|---|
| Permeate per unit | >127 m³/h | Achieved on all three units |
| Salt rejection | >99% | Stable through 7 days of continuous operation |
| Continuous run duration | 7 days | Counted from 2023-01-03 |
| Installation period | 7 days (12-18 to 12-25) | All three units re-membraned |
| Client rating | Product performance qualified, technical service qualified | Confirmed on the acceptance form |
Acceptance requires all three units to simultaneously meet the permeate flow and salt rejection requirements. Permeate flow is taken from on-site flow meters; salt rejection is calculated from feed and permeate conductivity.
05
Project Results
Client acceptance conclusions and reusable engineering experience
✓
Design permeate capacity restored
All three units now deliver more than 127 m³/h, a clear recovery from the pre-replacement decayed state, meeting peak boiler make-up demand.
✓
Product water quality back to design level
Salt rejection above 99% and falling permeate conductivity reduce the load on downstream polishing equipment.
✓
Short schedule, minimal downtime loss
Only 7 days from mobilization to completion, minimizing the impact of the outage on plant-wide steam and demineralized water supply.
✓
A model for channel-partner delivery
Bidding, supply and on-site technical service were completed jointly with Shaanxi Zhenghe Puye Environmental Technology, establishing a replicable channel cooperation model.
