2 kg/h Electrolytic Sodium Hypochlorite Generator

3.International Standards and Compliance

The original design referenced Chinese national standards. In this guide, each standard is mapped to an international equivalent selected by functional scope: manufacturing quality, water quality, drainage design, equipment safety, chemical conformity, vocabulary and hydrogen safety.

5.System Architecture and Process Flow

The QX-CL-2000-NaCLO is built as a skid mounted, prewired package. The diagram below shows how raw water, salt and power enter the system and how the finished disinfectant reaches the point of application.

Softening and brine preparation
The softening unit uses a dual tank, dual valve softener with CT100 ion exchange resin. It removes hardness from the process water so the brine entering the electrolytic cell stays soft and scaling is minimized. The softener regenerates automatically.

Salt is loaded into a 1000 L food grade PE dissolving tank. Softened water enters through a distribution header and dissolves the salt bed in the first pass. A circulation pump (60 L/h, 0.5 MPa, 0.37 kW) then recirculates the liquor through the distributor until the solution reaches saturation, without mechanical stirring. The saturated brine is metered into the dilution line, where it is mixed with softened water to the working concentration of 3.0% to 5.0%.

Generator main unit
The main unit houses the electrolytic cell, the rectifier power supply, the PLC based control centre, flow and temperature switches, salinity monitoring, a touch screen, a manual panel, and hazardous gas sensors.

The cell is a tubular UPVC reactor with PVDF separators between the plate electrodes. The housing is corrosion resistant and dimensionally stable. The plate electrodes are made of Grade 1 titanium (ASTM B265). Because the anode is consumed during electrolysis while the cathode is protected, the anode surface carries a dense coating of ruthenium and iridium oxides, applied with 20 nm particles in 25 or more layers to a thickness of 20 µm. The coating keeps the overvoltage low and gives the electrode a long, stable service life.

The high frequency, switch mode constant current constant voltage power supply converts AC to DC at more than 95% efficiency. It provides protection against input overvoltage, undervoltage and phase loss, output overvoltage, overcurrent and short circuit, and internal overheat. The power stage is sealed against corrosion, moisture and dust.

Storage tank and hydrogen removal
Electrolysis releases a small amount of hydrogen. Hydrogen is flammable, so the system keeps its concentration far below the flammability limit. International practice, as reflected in IEC 60079-10-1 and NFPA 2, is to keep the concentration below 25% of the lower flammability limit. For hydrogen, 25% of 4% by volume equals 1% by volume. The system is therefore designed to hold hydrogen below 1%, with an exhaust that works continuously.

The cell outlet stream passes through two stages of gas liquid separation. The first stage removes most of the hydrogen before the liquid enters the 50 L food grade PE storage tank, and the second stage removes the remainder. A 220 V AC, 200 W, 55 m³/h forced draft fan blows air through the tank headspace so residual hydrogen is diluted and discharged through the vent pipe. The tank carries high, medium and low level switches. When the tank is full the generator pauses; when the level falls back to the refill point the generator restarts.

Automatic dosing
The dosing package consists of a corrosion resistant diaphragm metering pump (30 L/h, 0.7 MPa, 0.37 kW) and a variable frequency drive. The drive receives the plant flow signal and the control centre closes the loop, so the hypochlorite dose follows the water flow automatically. The solution can be added before or after filtration, provided the mixing time is at least 30 minutes.

Online instrumentation
Every safety critical variable is measured and alarmed: process water pressure, dilute brine salinity, electrolyte temperature, electrode contact temperature, brine flow, and hydrogen concentration in the generator room. Each instrument provides an alarm output, and the control centre stops the generator if any value leaves its safe window.

Acid cleaning
Softened water still contains trace ions, so scale slowly builds up on the electrodes. The first signs are a fast rise in electrolyte temperature and a drop in current efficiency. When this happens, the system switches the relevant valves and fills the cell with dilute hydrochloric acid from the acid cleaning tank. The cell soaks for 30 minutes to dissolve the scale, then clean water flushes it. The acid tank is a 50 L food grade PE vessel.

6.Electrode Technology and Service Life

The electrode assembly is the heart of the generator and the main factor in operating cost. The serial electrode arrangement (patent ZL 201120488431.9) keeps both salt consumption and DC power consumption low. The anode coating is guaranteed for one year, and the assembly is designed for a normal service life of 10 to 15 years. The coating itself is rated for continuous service above 5 years, and electrodes can be recoated and returned to service. The design holds DC power consumption below 4.0 kWh per kilogram of chlorine.

7.Site Requirements and Installation

Utility requirements

• Water supply at or above 0.3 MPa pressure and 5 m³/h flow.
• Power supply of 380 V AC, 50 Hz, with a connected load of 100 kW per set.
• Dosing point arranged as pre chlorination or post chlorination, with a mixing time of at least 30 minutes.
• Well ventilated, dry equipment room with lightning protection and a drainage trench.

Installation requirements

1. The generator is installed indoors in an above ground room that is open to ventilation, with at least one wall directly exposed to the outside, no direct sunlight, and an ambient temperature above 10 °C.
2. Because sodium hypochlorite is a strong oxidizer, the generator must not share a room with other electrical equipment. A separate equipment room is required.
3. The control cabinet is installed in its own room, separate from equipment and raw materials.
4. Equipment and raw materials are stored in a dedicated chemical storage room on a concrete foundation.
5. The equipment room floor is concrete, with a washdown water supply and a floor drain connected to the drainage trench.
6. An axial fan is mounted high on the wall to keep the room well ventilated.
7. The room provides adequate lighting and a power supply sized for the connected load.
8. Strict electrical and fire safety rules apply inside the equipment room.

8.Frequently Asked Questions

What does 2 kg/h mean on an electrolytic sodium hypochlorite generator?

It means the generator produces 2000 g of available chlorine per hour, equivalent to a continuous output of a 6000 to 8000 ppm sodium hypochlorite solution at the rated brine flow. The model QX-CL-2000-NaCLO is sized for this output per main unit.

How does brine electrolysis produce disinfectant?

A direct current is passed through dilute brine in an electrolytic cell. Chloride ions are oxidized at the anode to chlorine, which reacts with water to form hypochlorous acid and hypochlorite ions. The resulting solution is a strong oxidant that inactivates bacteria, viruses and algae.

Is sodium hypochlorite generation safer than chlorine gas?

Yes. The disinfectant is made on site from salt, water and electricity, so there is no chlorine gas transport, storage or cylinder handling, and the stored solution volume is small and short lived.

Which standards does this generator follow?

The design applies international equivalents of the original Chinese standards, including ISO 9001:2015, NSF/ANSI 60 and 61, the WHO Guidelines for Drinking Water Quality, EN 752:2017, IEC 61010-1, ISO 6107, IEC 60079-10-1 and NFPA 2. See the standards table in this guide.

Why is hydrogen removal important?

Electrolysis forms a small amount of hydrogen, which is flammable. The system separates hydrogen in two stages and dilutes it with forced air, keeping the room concentration below 1% by volume, well under the 4% lower flammability limit.

How often do the electrodes need cleaning?

Cleaning is on condition. When the electrolyte temperature rises quickly or the current efficiency drops, scale has built up. The system then runs an automatic acid wash with dilute hydrochloric acid: a 30 minute soak followed by a fresh water flush.

How long do the electrodes last?

The electrode assembly is guaranteed for one year and designed for a normal service life of 10 to 15 years. The anode coating is rated for more than 5 years of continuous service, and the electrodes can be recoated.

What site conditions are required?

You need a water supply at or above 0.3 MPa and 5 m³/h, 380 V AC 50 Hz power, a ventilated indoor room above 10 °C, a separate room for the generator and control cabinet, a chemical storage room with a concrete foundation, a concrete floor with a drain, and an exhaust fan.

A 2 kg/h electrolytic sodium hypochlorite generator converts three simple inputs, salt, softened water and electricity, into a reliable disinfectant at the point of use. The QX-CL-2000-NaCLO packages softening, brine preparation, electrolysis, storage, dosing and safety instrumentation into one automatic system. It produces 2000 g of chlorine per hour at a DC power consumption below 4 kWh per kilogram, keeps hydrogen below 1% by volume, and runs unattended for 24 hours a day.

For project specific engineering, dosing point selection and local compliance review, contact the manufacturer with your water quality report and plant flow data.