Chemical Injection Skids
Precision dosing for demulsifier, scale inhibitor, corrosion inhibitor, and methanol -- single and multi-point injection systems, factory-assembled and ready for field connection.
Why Precise Chemical Injection Is a Production-Critical Function
Chemical injection is easy to underestimate until it fails. Undertreated separation trains produce off-spec crude. Undertreated water injection systems scale up within weeks. Undertreated pipelines corrode through in months. Chemical injection skids are not accessory items -- they are production maintenance systems whose performance directly determines the reliability and output quality of everything downstream.
Demulsifier Injection for Separator Performance
Crude oil emulsions -- stable mixtures of oil and water stabilised by naturally occurring surfactants and solids -- resist gravity separation. Demulsifier injection at the wellhead or separator inlet breaks the emulsion, reducing droplet coalescence time and improving oil-water separation efficiency. The correct demulsifier chemistry at the correct injection rate is the first variable in separator performance optimisation. Under-dosing produces no benefit; over-dosing wastes chemical and can re-stabilise the emulsion.
Scale Inhibitor Injection for Water Systems
Produced water frequently contains incompatible ion pairs that precipitate as scale when mixed or as temperature and pressure change. Scale deposits in wellbores, heat exchangers, and transfer lines reduce flow capacity and require costly cleaning. Scale inhibitor injected continuously at sub-ppm concentrations prevents scale before it forms. Continuous precision dosing, proportional to water flow rate, is the effective application method.
Corrosion Inhibitor Injection for Pipelines
CO₂ and H₂S in produced fluids are the primary drivers of internal corrosion in oil and gas pipelines and vessels. Corrosion inhibitor is injected continuously at low concentrations to maintain a protective film on metal surfaces. The injection skid must deliver the correct dose at the correct frequency; a control system that tracks injection volume, pump strokes, and chemical inventory provides the documentation record for corrosion management programme compliance.
Methanol and Hydrate Inhibitor Injection
Natural gas at high pressure and low temperature forms hydrates -- solid ice-like structures that can plug wellhead chokes and pipelines within hours. Methanol (or MEG) injected upstream of the hydrate formation risk point depresses the hydrate formation temperature. Methanol injection skids must be designed for high injection rates required during startup and cold flow conditions, capable of rapid rate adjustments.
Integration Reference
Chemical injection skids are supplied as standalone units or integrated components of LINSON OIL separator and wellhead packages.
What's in a Chemical Injection Skid -- and Why Each Component Matters
The Core Challenge: Delivering Microdoses Accurately Under Process Pressure
Chemical injection sounds simple -- pump chemical into a pipeline. The engineering complexity is in the precision and reliability requirements. Injection rates are typically measured in litres per hour or parts per million (ppm) relative to the process flow.
The chemical must be injected against the full process operating pressure -- often 5-15 MPa for wellhead or separator service -- without backflow of process fluid into the chemical system. The pump must deliver this dose consistently, 24 hours a day, with documentation that the correct dose was delivered.
Metering Pump Selection
The heart of a chemical injection skid is the metering pump. LINSON OIL specifies metering pumps for chemical injection service based on:
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Plunger (reciprocating) metering pumps: most widely used for chemical injection in oil and gas. Positive displacement; injection rate controlled by stroke length and frequency. Can inject against very high back-pressure (up to 70 MPa). Requires a pulsation dampener.
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Diaphragm metering pumps: process fluid contacts only the diaphragm -- no seal leakage of chemical possible. Preferred for toxic or hazardous chemicals. Lower back-pressure rating than plunger pumps.
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Peristaltic pumps: chemical contacts only the tube; used for smaller injection rates and lower-pressure service for aggressive/abrasive chemicals.
Key Skid Components
- Day Tank (Chemical Storage)
- Holds the working inventory of chemical at the injection point. Sized to hold 1-7 days of chemical. Material: carbon steel with internal epoxy lining or stainless steel. Includes fill connection, level gauge, low-level alarm, and vent.
- Suction Strainer
- Fine mesh strainer (40-100 mesh, 316L SS) on the pump suction protects the pump valves from particulates.
- Pulsation Dampener
- Installed on pump discharge to smooth the pulsatile flow from the plunger pump, reducing pressure fluctuations. Gas-charged bladder type.
- Calibration Column (Stroke Counter Vessel)
- A graduated glass/plastic cylinder on the pump suction that allows the actual pump output to be verified without stopping the process.
- Injection Check Valve & Quill
- Prevents process fluid backflow. The retractable injection quill extends into the centre of the process pipe flow, ensuring chemical is injected into the flowing stream for better dispersion.
- Control Panel
- Local start/stop, stroke rate adjustment, run/fault indication, low-level alarm, and optional 4-20 mA output to SCADA or ratio-to-flow control.
Engineering Specifications
Detailed parameters for standard and custom chemical injection skid packages.
Skid System Specification
| Number of Injection Points | 1 - 12 per skid |
|---|---|
| Injection Rate per Pump | 0.1 - 500 L/hr |
| Back-Pressure Rating | Up to 70 MPa (High-pressure service) |
| Pump Type | Plunger / Diaphragm / Peristaltic |
| Material (Wetted) | 316L SS / Hastelloy C-276 / PTFE / PVDF |
| Day Tank Volume | 200 L - 5,000 L per tank |
| Tank Material | CS + epoxy / 316L SS / HDPE |
| Hazardous Area | Zone 1 (ExdIIC) / Zone 2 (ExeIIC) |
| Design Code -- Piping | ASME B31.3 / GB/T 20801 (GC2) |
Chemical Compatibility -- Material Guide
| Chemical Service | Recommended Wetted Material |
|---|---|
| Demulsifier / Scale / Corrosion Inhibitor | 316L SS |
| Methanol / MEG | 316L SS |
| Biocide (glutaraldehyde or THPS) | 316L SS or Hastelloy |
| Hydrochloric acid (acidising) | Hastelloy C-276 or PTFE-lined |
| Sodium hypochlorite | PVDF-lined or HDPE |
| Drag reducer (polymer slurry) | 316L SS (Low-shear pump) |
Chemical compatibility verification is part of LINSON OIL's skid specification process -- clients are requested to provide chemical Safety Data Sheets (SDS) for all chemicals to be handled.
Standard Skid Package & Customization Options
Standard Supply (Included)
- › Structural skid frame (carbon steel; primer + finish coat)
- › Chemical day tank(s) with fill, drain, vent, level gauge
- › Metering pump(s) & Suction strainer per pump
- › Pulsation dampener (for plunger pumps)
- › Calibration column & Injection check valve per pump
- › Retractable injection quill per injection point
- › Skid piping (316L SS standard; GC2 licensed)
- › Local control panel & Pressure relief valve
- › FAT: pump stroke verification, rate calibration
- › Full documentation dossier
OEM / ODM Customization Options
GC2 Licensed Piping. Factory Calibrated. Delivered with Full Dosing Verification.
QA Process
Chemical Compatibility Review
SDS sheets reviewed against wetted materials to prevent premature pump/valve failure.
Pump Procurement & Verification
Performance curves confirm delivery rate vs. back-pressure. Factory test certificates reviewed.
Skid Assembly and Piping
Piping assembled per GC2 requirements. SS piping pickled/passivated. Flushed clean before FAT.
Factory Acceptance Test (FAT)
Pump calibration (±2% of setpoint), alarm function test, ratio control test. Client witness available.
Chemical Injection Skids -- Integrated Into Upstream Production Systems Across China and Internationally.
Integration with Separator and Wellhead Skid Packages
Chemical injection skids supplied by LINSON OIL are designed to interface directly with our separator skids, wellhead valve group skids, and gathering station packages. This integration ensures chemical injection points are positioned correctly (demulsifier upstream of separator; scale inhibitor on water outlet) and control systems are coordinated.
International Project Supply -- Congo (Brazzaville)
For the multi-phase Jiarou Oilfield gas processing project, chemical injection systems were included for demulsifier dosing, corrosion inhibitor treatment, and hydrate inhibition -- integrated into the overall gas processing facility delivered by LINSON OIL. Export logistics and documentation fully managed.
Warranty Terms
From commissioning or 26 months from shipment -- covering skid fabrication, piping integrity, pump mechanical components, and control panel function.
Note: Pump internal wear components (valves, diaphragms, seals) are consumables covered by manufacturer's component warranty. Replacement intervals are documented at delivery.
Long-term partners: up to 2.5 years, with priority access to replacement kits.
After-Sales Support
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Pump performance troubleshooting: remote support for injection rate deviations, wear diagnosis, and calibration drift correction.
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Chemical compatibility review: if formulation changes, we review material compatibility and advise on required component changes.
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Wear part replacement: recommended spare kits identified in quality dossier; available from LINSON OIL or direct from manufacturer.
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Additional engineering: design and supply of additional pump trains to interface with existing skids if new chemicals are needed.
Chemical, Flow Rate, Back-Pressure. We'll Specify the Pump and Size the Skid.
Chemical injection skid sizing requires four inputs: the chemical to be injected, required injection rate range, injection back-pressure, and area classification. Send us these parameters, and our engineers will specify the appropriate pump type, materials, and skid configuration within 1-2 business days.
Free Engineering Resource
Submit your parameters and receive:
- Pump type & material recommendation
- Preliminary skid configuration & dimensions
- Integration point location advice
*Reviewed by process & mechanical engineers.*
