Heat Recovery Steam Generators | HRSG’s | Types of HRSG’s | Classification of HRSG’s

Heat Recovery Steam Generators

Heat Recovery Steam Generator (HRSG) is a type of boiler  where no fuel is fired and the heat from the hot waste gas is  recovered for steam generation. It is also called as Waste Heat Boiler (WHB).

HRSGs are broadly classified into two types.

A.)  Modular Type (Had collaboration with M/s Vogt-NEM, USA) 

1. Gas flow is horizontal,

2. Applicable for clean hot gas,

3. Finned tubes are used, and,

4. Heat transfer sections are arranged along the gas flow direction like superheater, evaporator, economiser and condensate preheaters.

Vogt type HRSGs are further classified under the following heads:

1. Single/double/triple width HRSG

2. Single/dual/triple pressure HRSG

3. Top/bottom supported HRSG

4. Unfired/supplementary fired (using duct burner) HRSG 

B.) Furnace Type

1.Gas flow is vertical downward

2.Applicable for particle laden gas,

3.Only plain tubes are used,

4.Arrangement is similar to FBC/Utility boiler except that there is no firing of fuel.

Typical Two Width Triple Pressure HRSG

All these HRSGs are designed as per IBR and materials used for manufacturing pressure parts are as per ASME. Allowable Stress values for these materials are taken from ASME sec-II, Part-D.

Detailing Work:

As soon as we receive the order, following are the sequence of  activity to be done using the proposal documents & transmittals:

1.   Preparation of Applicable PGMA & Sub-delivery list for the boiler,

2. Material Forecast for raw materials and R-indent (with drg. and purchase specification) for sub-delivery items

3. Detailing work starts with the receipt of PPA & GA drgs.