Titanium heating tube bundles extensively applied in mineral leaching, catalyst suspension reaction, slurry wastewater treatment and solid-liquid two-phase chemical processes are continuously impacted and scoured by suspended solid particles, metal debris, pipeline rust fragments and accidental foreign impurities carried in flowing media. High-speed particle collision causes continuous micro-abrasion on titanium heating surfaces, stripping the intact titanium dioxide passive film layer locally. Meanwhile, the turbulent flow around heating bundles gathers abrasive particles to form sediment deposits in pipeline dead zones and tube bundle gaps, creating oxygen-concentration corrosion cells under particle accumulation. The coupling effect of mechanical abrasive wear and electrochemical under-deposit corrosion accelerates wall thinning and localized pitting, gradually evolving into penetrating tube bundle leakage and system shutdown accidents. Implementing standardized foreign object ingress interception specifications combined with real-time online particle concentration monitoring can block large abrasive impurities from entering heating sections, dynamically control slurry flow velocity and particle impact intensity, protect the continuous integrity of titanium passive films, and fundamentally reduce the erosion-corrosion failure risk of titanium heating tube bundles operating in harsh solid-liquid two-phase industrial environments.
Multi-stage graded filtration interception configuration is the core barrier to prevent mechanical foreign objects from entering titanium heating equipment. Single simple filter screens cannot intercept different sizes of abrasive impurities; a hierarchical filtering system shall be installed sequentially on the upstream pipeline of heating tube bundles. The primary coarse filter intercepts large metal fragments, plastic residues and agglomerated solid lumps to avoid direct high-energy impact deformation and passive film tearing on heating tube surfaces. Secondary fine filters trap fine suspended abrasive particles and pipeline rust debris to reduce the particle concentration of the medium flowing through the heating zone. Filter materials must adopt corrosion-resistant titanium alloy or fluoropolymer-lined structures compatible with process media to prevent filter material corrosion and secondary impurity generation. Regular differential pressure monitoring across the filter element judges the blockage degree; once the pressure difference exceeds the preset threshold, automatic backwashing or filter element replacement shall be executed to avoid filter rupture leading to massive impurity leakage into the heating tube bundle.
Online particle size and concentration real-time monitoring paired with flow velocity interlock adjustment effectively controls abrasive erosion intensity. Fixed laser particle sensors are installed at the upstream side of the heating tube bundle to continuously collect particle size distribution, mass concentration and medium flow velocity data. When the particle concentration exceeds the safe threshold or oversized abrasive particles are detected, the control system automatically reduces the circulating pump operating frequency to lower the medium flow rate, weakening the particle turbulent impact and wall scouring effect on titanium surfaces. For slurry media with high solid content, the maximum flow velocity must be limited within the anti-erosion design range of titanium materials to prevent continuous micro-abrasion stripping of passive films. Monitoring historical particle operation data can summarize the variation law of solid impurity content in different production batches, optimize filter cleaning cycles and avoid periodic high-concentration particle erosion-induced cumulative surface damage to heating tube bundles.
Tube bundle structural anti-abrasion optimization and periodic wall thickness inspection form a dual safeguard against erosion-corrosion failure. Flow deflector baffles are arranged at the medium inlet of the heating tube bundle to change the direct jet flow into uniform laminar flow, eliminating local high-speed impact hotspots on the front row of titanium heating tubes. Wear-resistant anti-scour protective sleeves are installed on vulnerable tube surfaces facing incoming flow to buffer particle collision energy. Quarterly ultrasonic wall thickness scanning is implemented on impact-prone tube sections and flow dead zones with serious particle deposition to track the annual wall thinning rate caused by erosion-corrosion. For areas with obvious local thinning, process flow field adjustment and filter system upgrading shall be carried out; meanwhile, surface polishing and chemical repassivation are adopted to repair abrasion-damaged passive films, preventing corrosion pits from expanding into penetrating leakage defects under long-term two-phase service conditions.
The following table displays classified foreign object prevention and particle monitoring protection schemes for different solid-liquid two-phase heating service scenarios:
表格
| Solid-Liquid Two-Phase Service Scenario | Recommended Foreign Object Prevention & Particle Monitoring Specification | Core Erosion-Corrosion Failure Prevention Value |
|---|---|---|
| High-concentration mineral slurry leaching titanium heating bundle | Two-stage coarse-fine graded filtration + laser particle online monitoring + inlet flow deflector layout | Blocks large abrasive ore particle impact and reduces turbulent flow scouring-induced passive film stripping |
| Catalyst suspension intermittent batch reaction heating unit | Regular filter differential pressure backwash + flow velocity upper limit interlock + semi-annual vulnerable tube thickness detection | Avoids periodic catalyst agglomerate leakage erosion and inhibits under-deposit pitting corrosion in tube bundle gaps |
| Slurry wastewater circulating heating system with pipeline rust impurities | Upstream magnetic filter + real-time particle concentration early warning + wear-resistant protective sleeve installation | Intercepts ferromagnetic metal abrasive debris and slows long-term wall thinning caused by coupling wear and electrochemical corrosion |
| Low-solid-content organic suspension liquid heating equipment | Single precision filter + monthly particle sampling inspection + annual tube bundle full non-destructive scanning | Realizes economical foreign object risk interception and eliminates hidden erosion-corrosion defects accumulated in long-term low-intensity particle scouring |
Foreign object graded interception and online particle monitoring cut off the source of passive film mechanical abrasion for titanium heating tube bundles in two-phase flow systems. Titanium's excellent uniform corrosion resistance cannot resist the combined damage of high-speed particle abrasive stripping and subsequent under-deposit localized electrochemical corrosion. Scientific upstream filtering barrier layout, flow field dynamic regulation and regular structural thickness monitoring effectively restrain erosion-corrosion degradation, extend the service cycle of heating facilities, and avoid huge economic losses caused by sudden tube bundle rupture and forced production shutdown in solid-liquid two-phase industrial production processes.
