Chemical injection systems are critical for delivering treatment chemicals in industrial processes. They help control corrosion, scale, biofouling, and other process risks across sectors like oil & gas, water treatment, power generation, and chemical manufacturing.
But even the best systems can fail—leading to poor treatment, equipment damage, or environmental violations.
This guide breaks down the 10 most common problems in chemical dosing systems, their causes, and proven strategies to prevent them.
1. How to Prevent Incorrect Chemical Dosing
What happens:
Overdosing wastes chemicals and causes corrosion. Underdosing leads to untreated systems, fouling, and reduced process efficiency.
Why it matters:
Misconfigured dosing results in inconsistent pH, microbial blooms, or scale accumulation—affecting heat exchangers, boilers, or membranes.
Prevention Measures:
- Use mass or ultrasonic flow meters for precise monitoring.
- Calibrate metering pumps monthly using calibration columns.
- Compare injection data with process KPIs (e.g., corrosion rates, turbidity).
- Set up alarms and SCADA-linked thresholds for flow deviation.
2. How to Deal with Clogged Injection Lines
What happens:
Chemical feed lines clog due to precipitation, biofilm growth, or reaction byproducts like calcium phosphate.
Impact:
Partial or complete blockages cause uneven dosing and require shutdowns for cleaning or pipe replacement.
Prevention Measures:
- Flush lines weekly with compatible solvents.
- Install inline strainers or Y-filters before the injection point.
- Use low-residue chemicals (e.g., chelated antiscalants).
- Schedule visual inspections and borescope evaluations.
3. How to Avoid Incompatible Chemical Reactions
What happens:
Certain chemicals (e.g., oxidizers and amines) can react to produce sludge, heat, or gases. These reactions damage injection components and clog dosing points.
Industries at high risk: Water treatment, chemical blending, and pharmaceutical production.
Prevention Measures:
- Review compatibility charts (e.g., NACE or supplier MSDS).
- Store incompatible chemicals in separate bunded enclosures.
- Use injection quills made of inert materials (e.g., PTFE, PVDF).
- Conduct lab-scale compatibility testing before full-scale mixing.
4. How to Prevent Pump Failures
What happens:
Chemical metering pumps (typically diaphragm or peristaltic) fail due to seal wear, dry runs, or motor burnout.
Impact:
Leads to complete stoppage of chemical injection—causing safety violations or plant downtime.
Prevention Measures:
- Perform biweekly pump inspections.
- Lubricate and replace seals, diaphragms, or check valves per manufacturer’s schedule.
- Install low-level switches to prevent dry running.
- Use redundant pumps (duplex configuration) for critical systems.
5. How to Detect and Prevent Leaks in Dosing Systems
What happens:
Leaks occur at threaded joints, compression fittings, or perished hoses. This causes safety risks, chemical waste, and inaccurate dosing.
Prevention Measures:
- Use compression or flare fittings with Viton/PTFE seals.
- Apply thread sealant or PTFE tape where required.
- Perform visual leak inspections weekly.
- Replace cracked tubing or corroded connectors immediately.
6. How to Handle Air or Gas Entrapment in Injection Lines
What happens:
Entrained air causes flow interruptions, erratic dosing, and pump cavitation.
Industries affected: Especially common in chemical dosing in water treatment, where degassed water enters dosing pumps.
Prevention Measures:
- Install air release valves at high points of piping.
- Prime pumps before startup and after every maintenance cycle.
- Use degassing heads or chambers on suction lines.
- Monitor pressure dips using inline sensors to detect air locks.
7. How to Ensure Sensor Accuracy in Chemical Injection
What happens:
Sensors (flow, pH, pressure, ORP) drift over time, get fouled, or suffer electrical interference—leading to false data and dosing errors.
Prevention Measures:
- Calibrate sensors quarterly or per site SOP.
- Use industrial-grade, shielded sensors with digital (Modbus/4-20mA) output.
- Replace any sensor showing erratic or delayed response.
- Mount sensors in stable, low-vibration zones, shielded from EMI.
8. How to Control Pressure Surges in Dosing Systems
What happens:
Sudden spikes from valve closures or pump starts can rupture hoses, damage injection quills, or backflow into storage tanks.
Industries affected: High-pressure dosing systems in oil & gas and pharma.
Prevention Measures:
- Install pressure relief valves and accumulators.
- Use regulators or dampeners to buffer pressure surges.
- Open/close valves slowly or use automated sequencing.
- Monitor transient pressure via high-frequency data logging.
9. How to Manage Temperature-Related Chemical Issues
What happens:
Low temperatures cause chemicals to thicken or crystallize. High temps degrade chemicals like hydrogen peroxide or sodium hypochlorite.
Prevention Measures:
- Store chemicals in temperature-controlled cabinets.
- Use heat-traced lines for cold environments.
- Select chemicals with wide temperature tolerances.
- Install temperature sensors on chemical tanks and pipelines.
10. How to Reduce Operator Error in Dosing Systems
What happens:
Operators may configure pumps incorrectly, choose the wrong chemical, or skip flushing steps—leading to safety hazards and poor process control.
Prevention Measures:
- Conduct regular operator training and certification refreshers.
- Use clearly labeled containers and color-coded lines.
- Implement digital checklists for startup/shutdown.
- Review incident logs monthly to identify recurring errors.
Final Thoughts: Prevention Saves More Than Repair
Most chemical injection system failures are preventable. Issues like dosing inaccuracies, blockages, sensor faults, or human error can lead to:
- Equipment damage
- Treatment inefficiency
- Environmental non-compliance
- Operator safety risks
Action Plan:
- Maintain a proactive maintenance schedule
- Choose chemically compatible equipment and materials
- Train staff continuously
- Monitor system health with real-time sensors and alarms
Need Help With Your Injection System?
Verito Engineering Pvt Ltd specializes in reliable solutions—designed for safety, precision, and durability. Whether you’re dealing with leaks, clogs, or system redesign, our team can help you fix it right.