Boiler & Heater Group

New Trends in Tail Gas Fired Boiler

Carbon Black Conference 2017 –

Chennai, India

Boiler & Heater Group

A leading engineering company providing equipment and solutions related to

Energy and Environment

About Thermax

Boiler & Heater

• Large capacity

power boilers

• Thermal oil /

water heaters

• Package

boilers

• Energy

recovery

systems

Turnkey Power Plants

• Solid fuel based

• Gas based combined

cycle

• Waste heat recovery

based

• RE based incl.

Biomass, Bagasse,

solar, etc.

• O&M of power plants

Chemicals

• Ion exchange

resins

• Cooling water

chemicals

• Fireside chemicals

• Polyelectrolyte

Water and

wastewater

• Wastewater &

Effluent water

treatment systems

• Water recycling

• Waste

management

Enviro

•ESP & Bag filters

• Scrubbers

• Air purification

• Retrofit &

Revamp

Boilers & Heaters Cooling & Heating Power Generation Chemicals & Water Air Pollution Control

THERMAX

Renewable

Solar

• Heating

• Cooling

Cooling

• Exhaust & Multi-

energy fired chillers

• Steam fired chillers

• Hot water fired

chillers

• Direct fired chillers

Heating

• Steam/Hot water

power plants

• Packaged solid/oil/gas

fired boilers

• Fired thermic fluid

heaters

• Exhaust waste heat

recovery boilers

Our Core Business

•Cement Heat Recovery

•Carbon Black

•Sponge Iron Exhaust

•Blast Furnace Gas

•Coke Oven Gas

•Coke Dry Quenching

•DG Set Exhaust Gas

•Gas Turbine Exhaust Gas

•Fluid Catalytic Cracking Unit

•Sulphur Recovery Plant

•Coal Gasification

•Sulphuric Acid Plant

•Incinerators

•Iron Pyrites Roasters

•Zinc Pyrite Roasters

•Copper Smelters

•Copper Convertors

•Glass Furnace

•Electric Arc Furnace

•Coke Calcination

•Nitric Acid

•Caprolactum

Experience in Waste Heat Recovery Applications

Key Points Flow Diagram of Carbon Black Making Process -

Fuel

Hot air

Cold

Air

Reactor

Burner

Reactor

Boiler

Feed

Heater

Tail

Gas to

Boiler

Tail Gas

to Dryer

Feed

Input

Reactor Air

Pre-heater

Bag Filter

Key Points

Tail Gas Utilization

• Tail gas is normally used for steam and power generation.

• In case of non-utilization for steam / power generation the tail gases are either incinerated or flared.

Key Points

Tail Gas Characteristics

• Typical constituents: CO, H2, CH4, N2, C2H2, O2, H2O, H2S, CO2

• Low Calorific value (LCV: 600 - 850 kcal/nm³) lean gas.

• Combustion requires Temperature, Time and Turbulence.

Key Points

Tail Gas Combustion Systems

• Water cooled furnace

• Refractory lined combustion chamber

Key Points

Typical ‘Tail Gas’ Fired Boiler Scheme

Stack

Burner

Economiser

Air preheater

Steam Drum

Convection Bank

Superheaters

Combustor

Key Points

Salient Features of the Tail Gas Fired Boiler

• Thermal Efficiency of 85 % (Based on LCV)

• Externally fired combustion chamber for complete combustion of tail gases.

• Tangential entry of tail gas along with radial entry of combustion and dilution air into combustor ensures complete combustion.

• Combustor Orientation : Horizontal / Vertical

• Sufficient residence time for complete combustion of lean gases

• No auxiliary fuel is required during normal operation.

• Forced Draft / Balanced Draft System

Key Points

Salient Features of the Tail Gas Fired Boiler

• Fully drainable Superheater.

• Superheater is placed in membrane panel construction, avoiding refractory lined casing.

• Screen tubes are provided before Secondary Superheater for protecting the same from direct radiation.

• Boiler Turndown Ratio – 1:4

Key Points

Salient Features of the Tail Gas Fired Boiler

• Rated superheat temperature is achieved for the given turn-down range because of Radiant Superheater.

• Convection section side walls consist of membrane panel construction. This ensures refractory less design.

• Boiler feed water pre-heater is provided to preheat feed water before entering Economiser. This ensures no corrosion of Economiser tubes.

• Bare tube Heat transfer surfaces to avoid gas side choking.

Key Points

Emission Control Methods

• NOx Reduction

• SOx Reduction

Key Points

Nox Reducing Methodology

• Low NOx Burners

• Air Staging

• Fuel Staging

• Flue Gas Recirculation

• DeNOx System - SNCR / SCR

Modularization

Combustion Chamber

Modularization

Boiler Block

Modularization

Economiser Section

Modularization

Refractory Lined Stack

Key Points Observations

• Captive power generation is a great success and makes these plants self sufficient.

• Continuous plant availability makes these plants highly reliable.

• If wheeling of power is allowed, Carbon black plants can be net exporters of power.

• Tail gas burning and conserving energy is also Environmentally friendly.

THANK YOU