Waste Heat Recovery Boilers WHRBs

Demand pattern of steam in the plant—whether it is steady or intermittently higher quantity of steam supply is required in the plant. 

Type of boiler required—water-tube type or smoke-tube (fire tube) type  

In case of fire-tube boiler, they may cost more for the same steam generation capacity since the tubes and the shell both are subjected to steam pressure. Water-tube boilers are generally used for power generation. They can start steam generation earlier than fire-tube boilers due to less volume of water in side. Only the tubes operate under pressure. The gases at low-pressure pass through the outer shell. The shell is therefore not subjected to steam pressure. Hence, cost could be less. 

Maximum pressure drop allowed on gas side. A single pass on gas side will have less pressure drop, but may need an external bypass duct (by purchaser) to prevent excessive cooling of the gases. 

Quality of feed water required by boiler manufacturer. 

---

The diverter valve operation is controlled by the waste heat recovery boiler (WHRB) and directs the exhaust gas to the WHRB boiler or out of the bypass stack to maintain the required steam pressure. The ABCO WHRB is rated at 30,000 Ib/hr and has two firing modes. In the turbine-firing mode, a 5.8MMBtu duct burner is available to supplement the turbine exhaust stream. In the direct-fire mode, used when the turbine is offline, the direct fresh-air Are at 41.5MMBtu is available. 

It can be generated by coal-fired boilers/or will be available from waste heat recovery boilers (WHRBs) which are heated by hot process gases, hot exit gases from the plant. 

Waste heat recovery boiler (WHRB) Heat generated during oxidation of ammonia is recovered to generate steam If water flow gets intermpted the boiler will be in danger Water-level controller is a must stop gas feed if water level is too low... 

It can be generated by the use of different fuels given above or by waste heat recovery boilers (WHRB) from hot process gases which need cooling as per process requirement. 

The SOa-containing gas leaving the furnace is cooled in a WHRB (waste heat recovery boiler), cleaned, and then admitted to the converter of the sulfuric acid plant. 

Waste heat recovery systems. WHRB 1 and WHRB 2, economiserfs), boiler feed water tank and pumps, raw water storage and water treatment plant for soft water/DM water, level controllers for WHRB, etc. 

---