Zhenjiang Boiler & Heat Exchanger Cleaning — Industrial Descaling & Chemical Cleaning Solutions

1. Zhenjiang Industrial Profile & Cleaning Demands

Zhenjiang sits on the south bank of the Yangtze River, forming a vital part of Jiangsu's riverside chemical industry belt and energy infrastructure. Key facilities include Jianbi Power Plant (a backbone power station for the East China Grid), SOPO Chemical, and Zhenjiang Chimei Chemical. The extensive boiler and heat exchanger assets operate under high utilization rates. Surface water from the Yangtze River, with its elevated silt content and hardness, leads to progressive deposition of carbonate scale, silicate scale, and iron oxide on heat transfer surfaces.

Field data shows that a mere 1mm scale layer increases boiler fuel consumption by 5–8% and reduces heat exchanger transfer coefficients by 30–50%. For chemical plants, process-side fouling adds organic compounds such as polymers and tar residues, forming composite scales far more tenacious than simple calcium-magnesium deposits. Industries along the Zhenjiang chemical corridor — producing caustic soda, acetic acid, and styrene — introduce highly corrosive process media, demanding precision in cleaning formulation and corrosion inhibition. At Jianbi Power Plant, silicate and iron oxide accumulation on water-wall tubes and superheater tubes not only degrades efficiency but also risks localized overheating and tube rupture. Regular professional cleaning of boilers and heat exchangers in Zhenjiang is thus both an energy-saving measure and a critical safety safeguard.

2. Common Fouling Patterns & Deposit Analysis

2.1 Boiler Scale Types

2.2 Heat Exchanger Challenges

Shell-and-tube and plate heat exchangers in Zhenjiang chemical plants face three primary challenges: cooling-water-side scaling on the shell side reducing heat transfer efficiency; process-side polymer and tar deposition causing flow-path blockages on the tube side; and chloride-induced stress corrosion cracking risk in stainless steel exchangers. Plate heat exchangers, with narrow flow gaps (typically 2–5 mm), foul 2–3× faster than shell-and-tube types, demanding more frequent cleaning intervention.

3. Cleaning Technology Solutions

3.1 Boiler Chemical Cleaning Formulation

For silicate scale common in Zhenjiang power plant boilers, EDTA sodium salt cleaning is the preferred approach. EDTA forms stable chelates with Ca²⁺, Mg²⁺, and Fe²⁺/Fe³⁺, effectively dissolving silicate deposits at elevated temperatures (120–140°C) with descaling rates exceeding 95%. Post-cleaning passivation with NaNO₂ or Na₃PO₄ forms a dense protective film on metal surfaces to prevent secondary corrosion.

3.2 Heat Exchanger Cleaning Protocols

Shell-and-Tube Heat Exchangers: Shell-side (cooling water) cleaning uses Sulfamic Acid circulation with BTA inhibitor for copper tube protection. Tube-side (process) cleaning employs solvent selection based on deposit analysis — tar and polymer fouling is first softened using alkaline Surfactant soaking, followed by high-pressure water jetting (500–800 bar) for tube-by-tube bundle cleaning. For severely coked exchangers, a soak-and-circulate alternating method is employed: 8–12 hours soaking, circulation at 0.5–1.0 m/s flow velocity.

Plate Heat Exchangers: Disassembly and individual plate inspection, gasket condition assessment. Cleaning solution: Sulfamic Acid (3%–5%) or Citric Acid (for stainless steel plates), 50–60°C, 2–4 hours circulation. Post-cleaning: individual high-pressure rinse (200–400 bar), visual inspection for residue, reassembly, and hydrostatic pressure testing.

3.3 Process Safety Controls

Real-time monitoring of cleaning solution pH, iron ion concentration, and corrosion inhibition rate throughout the operation. Minimum corrosion inhibition rate: ≥98% for carbon steel, ≥99% for stainless steel. Spent cleaning solution is neutralized to pH 6–9, flocculated, and settled before compliant discharge. Heavy-metal or organic-laden specialty waste is entrusted to licensed third-party disposal.

4. Service Coverage & Response Capability

Headquartered in Danyang (30 km from downtown Zhenjiang, ~40-minute drive), Danyang Lanxing provides full coverage across Zhenjiang: Jingkou District, Runzhou District, Dantu District, Danyang City, Jurong City, and Yangzhong City. Emergency response within 2 hours; routine technical proposals within 24 hours. Flexible scheduling supports both planned annual turnarounds (30-day advance site preparation) and emergency shutdown mobilization (equipment and crew deployed within 48 hours).

Equipment includes high-pressure water jetting units (up to 1000 bar), chemical cleaning circulation pump stations (max flow 50 m³/h), online pH/conductivity monitors, enabling 2–3 concurrent work fronts. All crews hold relevant certifications (hazardous chemical handling, working at height, confined space entry) and are covered by comprehensive project liability insurance.

5. Local Case Study

Equipment: A 20 t/h industrial steam boiler (model DZL20-1.25-AII) at a Zhenjiang chemical enterprise, operated for 5 years without comprehensive chemical cleaning. Drum waterside scale thickness: 2–3 mm.

Cleaning Approach: Composite cleaning with Sulfamic Acid (8%) + Citric Acid (3%), supplemented with 0.4% BTA inhibitor. Circulation at 55–65°C for 8 hours. Stubborn localized silicate deposits treated with EDTA sodium salt soaking for 12 hours.

Results: Descaling rate 96.7%, no over-pickling or pitting observed, corrosion inhibition rate 99.1%. Post-cleaning endoscopic inspection confirmed bare metal surface on the drum waterside, with no residual deposits at welds or expansion joints. Boiler thermal efficiency recovered from 78.5% to 86.2%, exhaust gas temperature dropped by 18°C, saving approximately 300 tonnes of coal annually. Six-month follow-up monitoring confirmed stable boiler water chemistry — pH, phosphate, and chloride all within specification. The client now schedules preventive chemical cleaning every two years as part of the annual maintenance plan.

6. Why Choose Lanxing

• Certified & Accredited: Member of China Industrial Cleaning Association and China Boiler & Boiler Water Treatment Association. 20+ years of industrial cleaning expertise with Grade B chemical cleaning and high-pressure water jetting certifications
• Proximity Advantage: Headquarters 30 km from Zhenjiang for rapid response and minimal downtime
• Full-Spectrum Capability: Chemical cleaning + high-pressure water jetting + passivation — one-stop service
• Safety Excellence: Fully certified crews, comprehensive HSE management, zero safety incidents over three years
• Local Expertise: Extensive experience with Zhenjiang chemical and power clients; in-depth knowledge of local water chemistry, Jianbi Power Plant boiler configurations, and chemical corridor process-media characteristics

Service Coverage: Jiangsu (Nanjing, Suzhou, Wuxi, Changzhou, Zhenjiang, Yangzhou, Taizhou, Nantong, Xuzhou, Lianyungang, Huai'an, Yancheng, Suqian) · Zhejiang (Hangzhou, Ningbo) · Shanghai · Anhui (Hefei) · Shandong · Henan

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