Sustainable Industrial Water
Through Thermal Engineering
Producing high-purity distillate from seawater — powered by waste heat, solar, or nuclear energy.
Converting Flue Gas Heat
Directly Into Vapour
Without the penalties of conventional systems — eliminating hot water loops, reducing footprint, and cutting auxiliary power consumption.
From Seawater to Distilled Water — Thermally
Thermal desalination is the process of evaporating and condensing water under vacuum conditions. This allows feed steam to be multiplied to produce distilled water with less than 2 ppm total dissolved solids from seawater containing 35,000–40,000 ppm.
This is achieved through a cascading series of effects operating at progressively lower pressures and temperatures. Each stage recovers energy from the previous stage, maximising thermal efficiency until the lowest practical temperature is reached.
At Vapour Desal Technologies, our systems are optimised for industrial environments where energy recovery, material durability, and long term operational reliability are critical
RO cannot use waste heat at all. Our systems use essentially free energy.
The Multi Effect Distillation (MED) Process
Integration Options
| Steam Supply Method | When to Use | Notes |
|---|---|---|
| Vacuum Vapour Generator (VVG) | Flue gas waste heat available (100–180°C) | ⭐Our Proprietary Innovation |
| Thermo Vapour Compressor (TVC) | Pressurized steam at 5–10 bar(a) | Standard method, TVC sourced externally |
| Low Temperature Flash (LTF) | Hot water available | Simple flash process |
Where Thermal Desalination Works
| Heat Source | Industry Example | Steam Supply Method |
|---|---|---|
| Thermal Power Plants | Coal, gas, or combined cycle plants | TVC / VVG |
| Solar Thermal Plants | Linear Fresnel Reflector (LFR) fields | TVC |
| Nuclear Facilities | Research reactors, nuclear power plants | TVC |
| Waste Flue Gas | Cement, steel, glass, or process industries | VVG |
| Low-Grade Waste Heat | Any industry rejecting heat to atmosphere | VVG / LTF |
| Ocean Thermal Gradient | Island and coastal installations | LTTD |
Note: Solar collection systems are implemented through specialist partners. Vapour Desal integrates thermal desalination with the solar heat source.
Why Thermal Desalination is a Long Term Solution
Exceptional Energy Efficiency
Due to the cascading nature of energy transfer within the system, thermal desalination is inherently energy-efficient:
| Metric | Value |
|---|---|
| Electrical energy consumption | 1.5–3 kWh per m³ of distillate |
| Primary energy source | Waste heat (essentially free) |
| Pumping power | Minimal — vacuum operation reduces mechanical load |
Note: Compare this to Reverse Osmosis (RO) at 3–6 kWh/m³ — and RO cannot use waste heat at all
Low Chemical Consumption
Thermal desalination requires only preventive dosing to discourage scaling on tube surfaces. There are no high pressure membranes and no frequent chemical cleaning cycles.
High-Purity Output
The distillation process produces water with less than 2 ppm TDS — significantly purer than typical RO permeate — making it ideal for:
Our Innovation — Rethinking Low-Grade Waste Heat Recovery
Vacuum Vapour Generator (VVG)
The VVG is a direct vapour generation heat recovery device operating under vacuum conditions. Instead of heating large quantities of circulating hot water and subsequently flashing it in a separate vessel, the VVG integrates these functions into a single compact unit.
Low Temperature Thermal Desalination (LTTD)
A niche technology using the natural temperature gradient of the ocean. Warm surface seawater evaporates under deep vacuum, and the vapour is condensed using cold deep-sea water
Applicability: Limited to specific coastal/island locations with access to deep cold water (600–1000m depth).
Our Experience: 3 × 150 m³/day plants delivered to Lakshadweep Islands.
Designed for Long Service Life
| Design | Specification |
|---|---|
| Design Life | 25 Years |
| Guaranteed Availability | 95% |
| Annual Downtime | 5 days/year (planned maintenance) |
| Output TDS | <2 ppm |
| Material Standard | Duplex Steel, Titanium Gr 2, SS 316L |
Rubber Grommet Innovation
A key innovation employed in our desalination plants is the use of rubber grommets to fix tubes to tube sheets.
● Prevents galvanic corrosion
● Extends tube life significantly
● Simplifies tube replacement
Applications
Rural & Island Water Supply
Power Plant Applications
Nuclear Facilities
Mineral & Resource Processing
Industrial Freshwater
Proven Across India & Beyond
| Projects | Location | Capacity | Technology | Year |
|---|---|---|---|---|
| Lakshadweep Islands | Amini, Kadamat, Chetlat | 3 × 150 m³/day | LTTD | 2018–24 |
| OSCOM IREL | Odisha | 2 × 250 m³/day | MED-TVC | 2020–23 |
| Mini Solar Desal (DST) | Kanyakumari, TN | 10 m³/day | Solar MED | 2018 |
| NTPC Simhadri | Andhra Pradesh | 120 m³/day | Flue Gas LTF-MED | 2017 |
| BARC | Mumbai | 240 m³/day | Nuclear MED-TVC | 2015 |
| RAMDAS | Narippaiyur, TN | 144 m³/day | Solar MED-TVC | 2011 |
Why Choose Vapour Desal Technologies?
Proven results under Indian field conditions — from tropical islands to industrial sites
25-year design life with 95% guaranteed availability
Design license from Dr. Marco Rognoni — a global pioneer in thermal desalination
Proprietary innovations like VVG and rubber grommet tube fixing
Integrated with solar, nuclear, and flue gas heat sources
High-grade materials — Duplex Steel, Titanium Gr 2, SS 316L
Decades of experience in custom evaporator and pressure vessel engineering
Ready to Explore Thermal Desalination?
Whether you have waste heat going up the stack or a remote community needing freshwater — we can design a solution that fits your site, energy source, and capacity requirement.
