MVR make-up steam from hot distillate
How a 60 m³-a-day ZLD effluent plant can make its MVR make-up steam and feed preheat with a water-source heat pump on warm distillate, against a briquette-fired steam boiler.
▶Video: Low-pressure steam from waste heat
V07 · 2–2.5 minWater-source R245fa heat pumps making 2 bar steam up to 120 °C
Video coming soon01Problem statement
- A boiler kept for make-up steam. MVR evaporators need a small but continuous steam make-up for vents and losses, so a boiler runs all day for a few percent of the duty.
- Warm distillate wasted. Distillate leaves the evaporator warm and is cooled in a tower or sent for reuse, discarding useful heat.
- Boiler compliance for a small load. The boiler brings fuel storage, ash, emissions consent and attendant costs for a small steam demand.
- Losses between fuel and process. Burning briquettes in a boiler or heater and distributing the heat loses a quarter or more of the fuel's energy before it reaches the process.
- Compliance, safety and handling. Fired equipment brings boiler inspections, fuel storage and unloading, flue emissions and an attendant on every shift.
02Use case
The reference ZLD plant treats 60 m³ a day of RO reject and high-TDS effluent from a chemical and pharma site. A mechanical vapour recompression evaporator concentrates it before crystallisation, running around the clock.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| MVR make-up steam | 2 bar steam | 60,000 kg/day evaporation × 3% make-up = 1,800 kg × 0.61 kWh/kg | 1,098 |
| Feed final preheat | 60 → 68 °C | 60,000 L/day after distillate preheater | 557 |
| Storage and pipework standing losses | – | about 5% | 83 |
| Total useful heat | 1,738 | ||
Averaged over 20 running hours, the heat pumps need about 87 kW.
03P&ID
Tags: HP heat pump, TK tank, SG steam generator, P pump, PHE plate heat exchanger, TCV temperature control valve, TIC temperature indicating controller (panel), TT temperature transmitter, MT moisture transmitter, PT pressure transmitter, LT level transmitter, FS flow switch, NC normally closed. Process fluids are heated through their own exchanger, coil or jacket.
04Solution
System description
- 4 × SE-WWUHT-27 (108 kW total) (SE-WWUHT water-source, R245fa) delivering 120 °C, covering the day's 1,738 kWh in about 16.1 running hours.
- Heat source: warm MVR distillate at about 60 °C.
- The briquette-fired steam boiler stays connected behind a normally closed valve as standby.
- Warm distillate at about 60 °C passes through the heat pump evaporator after the feed preheater.
- The heat pump makes 2 bar steam that enters the MVR vapour body as make-up, and supplies the final feed preheat.
- The boiler is kept for start-up and for the agitated thin-film dryer, which needs higher-pressure steam.
Selected equipment
| Model | SE-WWUHT-27 × 4 |
|---|---|
| Heating capacity | 27 kW each, 108 kW total |
| COP | 2.93 at the data sheet's rated condition (60/55 °C source water) |
| Power input | about 36.8 kW total at rated conditions |
| Rating | water or steam to 120 °C, R245fa |
| Supply temperature | 120 °C |
| Steam | 40 kg/h at 2 bar per SE-WWUHT-27 module |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
The steam header pressure controller starts and loads the heat pump to hold 2 bar. TIC-202 holds evaporator feed at 68 °C. On low distillate flow or low header pressure the PLC alarms and the boiler steam valve opens as standby.
05Energy saving and ROI
Change any input to match a customer's site. Defaults are typical Indian prices for October 2026. The installed cost is a placeholder; replace it with the actual quotation.
| Existing | Heat pump | |
|---|---|---|
| Daily consumption | – | – |
| Annual energy cost | – | – |
| Cost per m³ effluent treated | – | – |
| CO₂ per year | – | – |
06Benefits
Boiler off in normal running
Once the MVR is up to temperature, make-up steam comes from the heat pump.
Distillate cooled for reuse
Distillate leaves cooler and can go straight to reuse or the cooling tower.
Stable evaporator
Steady make-up steam keeps the vapour body pressure and boiling rate stable.
Lower energy cost
Each kWh of electricity delivers about 2.9 kWh of heat at the required temperature, against well under one kWh of useful heat per kWh of fuel burnt.
No flame on site
No burner, flue or fuel tank for this duty, and no fuel deliveries to schedule.
Built-in redundancy
Several machines share the load. If one is serviced, the others and the storage carry most of the day, with the existing heater in reserve.
07Engineering pointers
Site data to collect
- Evaporation rate and running hours
- Make-up steam rate and pressure
- Distillate flow and temperature
- Feed temperature after the existing preheater
- Present boiler fuel use for the ZLD plant
- Present fuel or electricity use and monthly bill
- Sanctioned electrical load and spare capacity
- Space for the heat pumps and storage, with service access
Design notes
- Clean steam side. Make-up steam enters the vapour body. Feed the heat pump steam generator with softened or RO water.
- Distillate quality. Distillate can carry ammonia or volatile organics. Specify stainless steel on the source side and check the analysis.
- Start-up. Bringing the MVR from cold needs more steam than the make-up rate. Keep the boiler or an electric steam generator for start-ups.
- Electrical. About 37 kW of heat pump input at rated conditions, plus pumps and fans. Check spare sanctioned load before ordering.
- Source stream. The source must give up roughly two-thirds of the heat delivered. Confirm its flow and temperature over a full production day, and filter it before the evaporator.
- Water quality. Scale forms quickly above 60 °C. Use softened make-up and keep the heat pump loop closed, with process fluids on the far side of an exchanger or coil.
Service and warranty
Sunniva has supplied 5,000+ heat pumps since 2012, with nine service technicians across India, including remote sites such as Leh. All components carry a one-year warranty.
Talk to us
MVR make-up steam from hot distillate
How a 60 m³-a-day ZLD effluent plant can make its MVR make-up steam and feed preheat with a water-source heat pump on warm distillate, against a briquette-fired steam boiler.
▶Video: Low-pressure steam from waste heat
V07 · 2–2.5 minWater-source R245fa heat pumps making 2 bar steam up to 120 °C
Video coming soon01Problem statement
- A boiler kept for make-up steam. MVR evaporators need a small but continuous steam make-up for vents and losses, so a boiler runs all day for a few percent of the duty.
- Warm distillate wasted. Distillate leaves the evaporator warm and is cooled in a tower or sent for reuse, discarding useful heat.
- Boiler compliance for a small load. The boiler brings fuel storage, ash, emissions consent and attendant costs for a small steam demand.
- Losses between fuel and process. Burning briquettes in a boiler or heater and distributing the heat loses a quarter or more of the fuel's energy before it reaches the process.
- Compliance, safety and handling. Fired equipment brings boiler inspections, fuel storage and unloading, flue emissions and an attendant on every shift.
02Use case
The reference ZLD plant treats 60 m³ a day of RO reject and high-TDS effluent from a chemical and pharma site. A mechanical vapour recompression evaporator concentrates it before crystallisation, running around the clock.
| Heat user | Process temp. | Basis | Heat, kWh/day |
|---|---|---|---|
| MVR make-up steam | 2 bar steam | 60,000 kg/day evaporation × 3% make-up = 1,800 kg × 0.61 kWh/kg | 1,098 |
| Feed final preheat | 60 → 68 °C | 60,000 L/day after distillate preheater | 557 |
| Storage and pipework standing losses | – | about 5% | 83 |
| Total useful heat | 1,738 | ||
Averaged over 20 running hours, the heat pumps need about 87 kW.
03P&ID
Tags: HP heat pump, TK tank, SG steam generator, P pump, PHE plate heat exchanger, TCV temperature control valve, TIC temperature indicating controller (panel), TT temperature transmitter, MT moisture transmitter, PT pressure transmitter, LT level transmitter, FS flow switch, NC normally closed. Process fluids are heated through their own exchanger, coil or jacket.
04Solution
System description
- 4 × SE-WWUHT-27 (108 kW total) (SE-WWUHT water-source, R245fa) delivering 120 °C, covering the day's 1,738 kWh in about 16.1 running hours.
- Heat source: warm MVR distillate at about 60 °C.
- The briquette-fired steam boiler stays connected behind a normally closed valve as standby.
- Warm distillate at about 60 °C passes through the heat pump evaporator after the feed preheater.
- The heat pump makes 2 bar steam that enters the MVR vapour body as make-up, and supplies the final feed preheat.
- The boiler is kept for start-up and for the agitated thin-film dryer, which needs higher-pressure steam.
Selected equipment
| Model | SE-WWUHT-27 × 4 |
|---|---|
| Heating capacity | 27 kW each, 108 kW total |
| COP | 2.93 at the data sheet's rated condition (60/55 °C source water) |
| Power input | about 36.8 kW total at rated conditions |
| Rating | water or steam to 120 °C, R245fa |
| Supply temperature | 120 °C |
| Steam | 40 kg/h at 2 bar per SE-WWUHT-27 module |
Ratings from the Sunniva TDS 2026 data sheets.
Control philosophy
The steam header pressure controller starts and loads the heat pump to hold 2 bar. TIC-202 holds evaporator feed at 68 °C. On low distillate flow or low header pressure the PLC alarms and the boiler steam valve opens as standby.
05Energy saving and ROI
Change any input to match a customer's site. Defaults are typical Indian prices for October 2026. The installed cost is a placeholder; replace it with the actual quotation.
| Existing | Heat pump | |
|---|---|---|
| Daily consumption | – | – |
| Annual energy cost | – | – |
| Cost per m³ effluent treated | – | – |
| CO₂ per year | – | – |
06Benefits
Boiler off in normal running
Once the MVR is up to temperature, make-up steam comes from the heat pump.
Distillate cooled for reuse
Distillate leaves cooler and can go straight to reuse or the cooling tower.
Stable evaporator
Steady make-up steam keeps the vapour body pressure and boiling rate stable.
Lower energy cost
Each kWh of electricity delivers about 2.9 kWh of heat at the required temperature, against well under one kWh of useful heat per kWh of fuel burnt.
No flame on site
No burner, flue or fuel tank for this duty, and no fuel deliveries to schedule.
Built-in redundancy
Several machines share the load. If one is serviced, the others and the storage carry most of the day, with the existing heater in reserve.
07Engineering pointers
Site data to collect
- Evaporation rate and running hours
- Make-up steam rate and pressure
- Distillate flow and temperature
- Feed temperature after the existing preheater
- Present boiler fuel use for the ZLD plant
- Present fuel or electricity use and monthly bill
- Sanctioned electrical load and spare capacity
- Space for the heat pumps and storage, with service access
Design notes
- Clean steam side. Make-up steam enters the vapour body. Feed the heat pump steam generator with softened or RO water.
- Distillate quality. Distillate can carry ammonia or volatile organics. Specify stainless steel on the source side and check the analysis.
- Start-up. Bringing the MVR from cold needs more steam than the make-up rate. Keep the boiler or an electric steam generator for start-ups.
- Electrical. About 37 kW of heat pump input at rated conditions, plus pumps and fans. Check spare sanctioned load before ordering.
- Source stream. The source must give up roughly two-thirds of the heat delivered. Confirm its flow and temperature over a full production day, and filter it before the evaporator.
- Water quality. Scale forms quickly above 60 °C. Use softened make-up and keep the heat pump loop closed, with process fluids on the far side of an exchanger or coil.
Service and warranty
Sunniva has supplied 5,000+ heat pumps since 2012, with nine service technicians across India, including remote sites such as Leh. All components carry a one-year warranty.