The following is a detailed description of the influencing factors of the online oil analyzer in water:
1、 Characteristic factors of water samples
1. Properties of oil substances: Different types of oil (such as mineral oil, animal and vegetable oil) have significant differences in their chemical composition, viscosity, and solubility in water. For example, light petroleum fractions are volatile and partially soluble in water, while heavy fuel oils tend to form lotion or suspensions, which puts forward differentiated requirements for separation and enrichment technologies (such as infrared method, ultraviolet method or fluorescence method) used by the instrument. If the instrument is not optimized for specific oil types, it may lead to deviation in the detection results.
2. Emulsification degree: Water samples containing surfactants are prone to form stable emulsions, resulting in extremely small oil droplet sizes (<1 μ m). Traditional gravity separation methods are difficult to effectively extract, and ultrasonic crushing or centrifugal assisted methods are needed to improve extraction efficiency. The analysis process that does not fully consider the emulsification state is prone to underestimating oil concentration due to incomplete stratification.
3. Suspended solids and turbidity: Particles such as sediment and metal hydroxide colloids in high turbidity water samples can scatter light sources and interfere with the signal acquisition of optical detection methods. Even with pre filtering devices, fine particles may still deposit on the surface of the detection tank window, forming baseline drift caused by memory effects.
2、 Instrument performance and design factors
1. Applicability of detection principle: Instruments based on non dispersive infrared (NDIR) technology are sensitive to aromatic ring structures and are suitable for most petrochemical products; The fluorescence method is more suitable for detecting polycyclic aromatic hydrocarbons. If the dominant oil component in the actual water sample does not match the optimal response band of the instrument, it will directly affect the detection limit and accuracy.
2. Flow path design and material: The dead volume of the flow pool structure and the vortex area at the pipeline connection are prone to become oil stains retention points, which gradually release false signals after long-term operation. Choosing inert materials such as PTFE can reduce adsorption effects, but attention should be paid to the risk of deformation under high temperature conditions.
3. Stability of calibration system: The selection of standard oil products should cover the typical composition of target pollutants, and a single standard solution is difficult to cover the matrix effects of complex mixed systems. Setting the frequency of the automatic calibration function too low can lead to zero drift accumulation, especially in environments with high salinity or acid-base fluctuations.
3、 Environmental and operational factors
1. Temperature and humidity fluctuations: The performance of optical components (such as light sources and detectors) is significantly affected by temperature, and sudden temperature changes beyond the compensation range can cause wavelength shifts. The high humidity environment accelerates the fogging of the optical window, and a dehumidification module needs to be configured to maintain the dryness of the detection chamber.
2. Pressure shock protection: Sudden high pressure at the inlet end (such as rapid opening and closing of valves) may cause deformation of the sensor diaphragm, affecting the transmission path of trace oil droplets. Installing buffer tanks and precision pressure regulating valves can smooth pressure fluctuations and ensure flow path stability.
3. Regular maintenance standards: Long solvent replacement cycles can lead to decreased extraction efficiency and increased column contamination; If the waste liquid discharge pipeline is blocked, it may flow backwards into the pollution detection unit. It is crucial to establish a preventive maintenance calendar and predict the timing of consumable replacement based on historical data.
The application effect of online oil analyzer in water is constrained by multiple factors, and it is necessary to select a suitable technical solution based on actual working conditions, and achieve accurate monitoring through dynamic calibration, environmental control, and standardized operation and maintenance.