HH2500D Water Online Process pH Electrode for Desulfurization & Denitrification Processes Electrode | Reinforced Cylindrical pH Glass Membrane |FGD/DeNOx Applications

The HH2500D is a combination pH electrode developed for monitoring liquid absorbents, slurries, and wastewater associated with flue-gas desulfurization and industrial exhaust-gas treatment. These processes can expose an electrode to suspended solids, deposits, sulfur-containing compounds, dissolved metals, fluctuating chemistry, and abrasive particles.

Its cylindrical HA pH-sensitive glass membrane provides a large sensing area and supports measurement across pH 0–14 in compatible acidic and alkaline aqueous media. The reinforced membrane is intended to provide greater mechanical durability in process installations, although it should still be protected from direct impact and highly abrasive flow.

The reference system uses a specially formulated SRG synthetic-gel intermediate electrolyte selected for sulfur-containing process media. A double-junction construction adds a second barrier between the process and internal reference element, helping slow the migration of contaminants into the internal reference system.

A PTFE junction is available to provide a relatively broad, low-adhesion contact area in fouling-prone scrubbing media. Ceramic junction configurations can also be supplied where appropriate for the process. The final junction design should be selected according to the sample’s solids, scaling tendency, flow conditions, and cleaning method.

With a PG13.5 connection, selectable insertion lengths, multiple connector options, and optional integrated temperature sensors, the HH2500D can be configured for compatible immersion, inline, and retractable process assemblies.

Standard configurations operate at pressures up to 3 bar. An enhanced version is available for applications requiring pressures up to 6 bar, subject to the applicable temperature, holder, seals, and complete installation arrangement.

Key benefits

• Developed for gas-treatment liquids: Intended for FGD slurry, scrubber liquor, and related wastewater—not direct gas-phase measurement.
• Specialized SRG electrolyte: Formulated for reference-system operation in sulfur-containing process media.
• Double-junction reference: Adds a second barrier between the contaminated sample and internal reference element.
• Configurable process junction: PTFE and ceramic junction arrangements are available for different fouling and solids conditions.
• Cylindrical HA membrane: Provides a large sensing area for compatible acidic and alkaline process liquids.
• Flexible process integration: PG13.5 connection and insertion lengths from 120 to 425 mm.
• Optional reinforced construction: Available for process pressures up to 6 bar.

Configuration options

• Insertion length: Selectable from 120 to 425 mm according to the holder and required immersion depth.
• Junction configuration: PTFE junction or dual porous-ceramic junction according to process conditions.
• Enhanced pressure construction: Available for process pressures up to 6 bar.
• Connector configuration: Multiple detachable cable and connector formats are available.
• Extended cable: Cable lengths up to 60 metres, subject to transmitter compatibility and site electrical conditions.
• Integrated temperature sensor: Selectable NTC, Pt100, and Pt1000 options.

Application and installation notes

The HH2500D measures the pH of the liquid absorbent, slurry, or wastewater used in gas treatment. It does not measure SO₂, NOₓ, or other components directly in the gas phase.

Install the electrode where the liquid is representative and adequately mixed, but avoid direct exposure to sediment beds, high-velocity abrasive slurry, reagent injection points, and large gas bubbles. Provide access for regular inspection and cleaning.

FGD and scrubber liquids can contain gypsum, limestone, fly ash, chlorides, sulfite, sulfate, metals, and other contaminants. Actual junction performance and maintenance frequency depend on the specific process composition and solids loading.

For DeNOx applications, confirm that the process includes an aqueous stage where pH measurement is meaningful. Many dry or catalytic DeNOx systems do not require a process pH electrode.

The 6 bar option must be verified against the actual temperature and the ratings of the electrode, holder, seals, process fitting, and cable connection.

Application

• Flue-Gas Desulfurization (FGD)
• Wet Scrubbing & Gas Treatment
• Industrial Exhaust-Gas Treatment
• Scrubber Wastewater Treatment
• Power Generation
• Industrial Air-Pollution Control