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The hardware behind our thermal SaaS

Biomass and gas. Built in our own shop.

Every boiler we put under a thermal-SaaS contract is engineered, fabricated and commissioned by our own team. Five biomass series — DHL, SZL, SHL, DZW and DHF — cover chain-grate, reciprocating-grate and fluidised-bed combustion from 2 to 200+ TPH, alongside hydrogen-ready WNS, SZS and DSMK gas units. And the fleet just grew: our new EH and ER electric boilers, powered by renewables, now take the zero-emission duties.

5 biomass series H₂-ready gas range NEW electric range IBR · PED certified
00+ TPH
Steam capacity per unit across the portfolio
0%+
Thermal efficiency on biomass chain-grate designs
0%
Gas condensing efficiency with integrated economiser + condenser
0mg/m³
Ultra-low NOx on premixed and condensing gas burners
Biomass boilers · Our flagship

Five biomass series, one for every fuel chain.

Briquettes, pellets, paddy husk, bagasse and mixed agro-residues each burn differently. Chain grate, reciprocating grate or fluidised bed — we match the combustion mechanism to your fuel supply chain and load profile, then build the boiler ourselves.

DHL series · Flagship workhorse

Single-drum transverse chain-grate boiler

Horizontal three-pass water-and-fire-tube design with screw-pipe convective surfaces and light chain-grate firing. Compact, factory-assembled, short installation window — the workhorse of our mid-to-large thermal-SaaS sites.

Capacity15 – 35 TPH steam
Pressure1.25 / 1.60 / 2.50 MPa
Efficiency~86.5%
Steam temp194 – 225 °C
Best fuelBriquettes · pellets
Chain grate Three-pass Factory-assembled
SZL series · Steady mid-pressure

Twin-drum longitudinal chain-grate boiler

Membrane water wall at the combustion chamber, dense convective tube bank between upper and lower drums, separately-laid economiser, dust collector and stack. Built for steady mid-pressure steam, day after day.

Capacity6 – 30 TPH steam
Pressure1.0 / 1.25 / 1.60 / 2.50 MPa
Heating surface24.5 – 109 m²
Steam temp194 – 225 °C
Best fuelBriquettes · pellets · chips
Twin-drum Chain grate Membrane wall
SHL series · Estate-scale

Twin-drum bulk site-assembled boiler

Bulk-shipped large-capacity design, assembled on site with chain-grate firing. The widest fuel tolerance of our grate boilers — mixed agro-waste, wood chips, bark and oversize feedstock that doesn't pelletise well. Built for large industrial estates.

Capacity35 – 75+ TPH steam
Pressure1.25 / 2.5 / 3.82 MPa
AssemblyBulk, on site
Best fuelMixed agro-waste · chips · bark
Twin-drum Site-assembled Mixed fuel
DZW series · High-ash specialist

Single-drum reciprocating-grate boiler

Longitudinal single-drum design with a reciprocating grate that mechanically agitates the fuel bed. Forgiving with low-grade biomass and high-ash residues like paddy husk and mustard stalk — the grate keeps the bed turning so combustion stays even.

Capacity4 – 25 TPH steam
Pressure1.0 – 2.5 MPa
GrateReciprocating, agitated bed
Best fuelPaddy husk · high-ash residues
Reciprocating grate High-ash tolerant
DHF circulating fluidised-bed biomass boiler cutaway
DHF series · Fluidised bed

Circulating fluidised-bed:
the widest fuel tolerance of all five.

Horizontal single-drum CFB design with in-bed sand fluidisation. It digests everything from paddy husk and bagasse to mixed shredded chips — with low NOx in-bed, SOx capture via limestone addition and excellent turndown for variable industrial loads.

Capacity20 – 100+ TPH steam
Pressure1.6 – 5.3 MPa
Turndown30 – 105%
EmissionsLow NOx + in-bed SOx capture
Best forMixed biomass · variable load
Inside the firebox

Four combustion stages,
controlled by staged air injection.

Biomass burns in sequence — and each stage is governed by primary, secondary and tertiary air, tuned continuously by the combustion controller.

  • 1
    Drying · 100–150 °C. Surface moisture flashes off under low-velocity primary air.
  • 2
    Devolatilisation · 350–500 °C. Around 75% of the fuel mass releases as volatiles, forming the flame at the secondary-air front.
  • 3
    Volatile combustion · 900–1,100 °C. Gas-phase burnout of CO, H₂, CH₄ and tars in suspension, completed by tertiary air.
  • 4
    Char burnout · 1,100–1,200 °C. Solid carbon burns out on the grate under primary underfire air, leaving clean ash for cement and brick offtake.
Biomass boiler cutaway showing chain-grate combustion and tube bank
Gas-fired range · All hydrogen-blend ready

Where the biomass chain doesn't reach,
gas does — with a hydrogen exit ramp.

For sites without viable biomass supply, or where footprint and emissions constraints favour gas. Every new gas boiler ships with burners rated for up to 30% hydrogen blending and a documented conversion path to 100% green H₂.

WNS series · Three-pass & condensing

Wet-back fire-tube steam boilers

Corrugated furnace, threaded smoke pipes and full wet-back construction. The condensing variant adds an integrated economiser and condenser that recover an extra 4–8%, pushing total efficiency to 103%. Siemens PLC with intelligent 30–105% load adjustment.

Capacity1 – 30 TPH steam
Pressureup to 2.5 MPa
Efficiency96–98% · 103% condensing
NOx≤ 30 mg/Nm³
FuelsNG · LPG · diesel · biogas
H₂-blend readySiemens PLC
SZS series · Water-tube

D-type water-tube steam boilers

Twin drums, membrane water walls and a dense convective bank. Saturated and superheated variants with fast steam ramp-up — the right architecture when demand exceeds what a fire-tube shell can scale to cleanly.

Capacity10 – 40 TPH
Pressureup to 5.3 MPa
SteamSaturated or superheated
ConfigurationD-type · twin drum
Best forLarge process · refineries
H₂-blend readySuperheat capable
DSMK series · Premixed condensing

Full-premixed condensing hot water boilers

Air and gas mix before the burner head for the cleanest possible flame — ultra-low emissions, deep turndown, compact modular footprint. Designed for hotels, hospitals and premium commercial buildings.

FormatModular commercial cascades
CombustionFull premixed
Efficiency98%+ condensing
NOx≤ 30 mg/Nm³
H₂-blend readyUltra-low NOx
Hydrogen-ready burners

Built for the fuel that comes next

Dual-fuel modulating burners rated for 30% H₂ blending out of the box, H₂-compatible 316L gas trains, tri-fuel safety interlocks and a documented conversion procedure to 100% green hydrogen. Because tariff capex recovery is separated from fuel pass-through, the switch happens mid-contract — no renegotiation, no stranded asset.

Blending todayup to 30% H₂
Conversion path100% green H₂, documented
Gas train316L · H₂-compatible
No stranded assetsMid-contract switch
New in the fleet · Electric, powered by renewables

No firebox at all. Zero on-site emissions.

The newest boilers in our shop don't burn anything. EH electrode and ER resistance units, fed by dedicated solar and wind PPAs, convert ~99% of every kilowatt into steam — no stack, no fuel yard, no ash. Same zero-CAPEX thermal-SaaS contract as everything else on this page.

EH series — high-voltage electrode

Current passes directly through treated boiler water between electrodes — MW-scale steam in a compact vessel with 0–100% ramp in seconds.

Capacity3 – 60 TPH steam
Supply6.6 / 11 kV · 2 – 45 MW
On-site emissionsZero — no stack

ER series — immersion resistance

Rugged stepped element banks on a 415 V LT connection — plug-and-play skids for pharma, F&B, laundries and hotels, paralleling up as demand grows.

Capacity0.1 – 6 TPH steam / hot water
Supply415 V LT · 75 kW – 4.5 MW
On-site emissionsZero — renewable-powered

Powered by renewables, dispatched by ClearOS™

Solar and wind PPAs, thermal storage and renewable-hour load shifting come bundled with every electric tariff — and on hybrid sites, an electric unit pairs with the biomass boilers above to catch peaks and soak up cheap solar hours.

Clear Energy fabrication shop — CNC plate rolling and welding line
In-house fabrication

Every drum, every tube bank,
welded under our own roof.

Our PESO-approved fabrication shop runs an Industry-4.0 line: 95% automation on biomass-side pressure parts, 90% across the gas portfolio. Nothing ships until it has passed hydro test and X-ray NDT.

  • PESO-approved shop with IBR certification for India and PED for European projects.
  • IBR-certified welding on every pressure joint, executed by coded welders with full traceability per drum.
  • Robot welding on tube-plate joints, with vertical and circular seam platforms for drum assembly.
  • CNC plate rolling and plasma cutting across all pressure-part fabrication, plus automated membrane-wall production.
  • Screw-pipe and spoiler-coil tubes rolled in-house — lifting convective heat transfer 8–12% over plain tube.
From the shop to the steam main

We don't sell these boilers.
We operate them — for decades.

Cyclone, baghouse and stack at the back; control room and ash handling at the base; fuel feed routed in by screw conveyor from the on-site yard. Because every unit runs under our own 98–99.5% uptime SLA, the fabrication shop answers to the operations team — the strongest quality incentive there is. See how the thermal-SaaS contract works →

Industrial steam piping fabricated and installed by Clear Energy
Boiler selection · answered in two working days

Tell us the steam demand. We'll spec the right boiler.

Send your site location, fuel availability, capacity (TPH or MW), pressure and temperature requirements, plus any local emissions limits. We'll return a recommended series — biomass, gas or electric — an indicative tariff and an installation timeline.