Heating system for heating heat-transfer oil usingboiler flue gas

Abstract

A heating system for heating heat-transfer oil using exhaust heat of boiler flue gas. The system includes: a flue, an economizer, an air preheater, and a heat-transfer oil heater. The economizer and the air preheater are disposed in the flue along the flow direction of the flue gas. The heat-transfer oil heater is disposed inside the flue in front of the economizer and is connected to a heat consumption device via a first circulating pipe. The circulating pipe is equipped with a circulating pump.

The invention claimed is: 
     
         1 . A heating system for heating heat-transfer oil using exhaust heat of boiler flue gas, the system comprising:
 a) a flue ( 1 );   b) an economizer ( 3 );   c) an air preheater ( 4 ); and   d) a heat-transfer oil heater ( 2 );   wherein   the economizer ( 3 ) and the air preheater ( 4 ) are disposed in the flue along a flow direction of the flue gas;   the heat-transfer oil heater ( 2 ) is disposed inside the flue ( 1 ) in front of the economizer ( 3 ) and is connected to a heat consumption device ( 19 ) via a first circulating pipe; and   the circulating pipe is equipped with a circulating pump ( 12 ).   
     
     
         2 . The system of  claim 1  further comprising an exhaust heat utilization device, wherein
 the exhaust heat utilization device comprises a heat absorption member ( 5 ) and a heat release member ( 6 ) communicating with each other through a second circulating pipe; 
 the heat absorption member ( 5 ) is disposed inside the flue behind the air preheater ( 4 ); and 
 the heat release member ( 6 ) is arranged on a water inlet pipe of the economizer ( 3 ) or inside an air inlet channel of the air preheater ( 4 ). 
 
     
     
         3 . The system of  claim 2 , wherein the heat release member ( 6 ) is arranged on the water inlet pipe of the economizer ( 3 ), the water inlet pipe of the economizer is provided with a deaerator ( 14 ) and a high pressure heater ( 11 ) for allowing boiler feedwater to pass through the heat release member ( 6 ), the deaerator ( 14 ), and the high pressure heater ( 11 ), respectively, to enter the economizer ( 3 ). 
     
     
         4 . The system of  claim 3 , wherein a feedwater pump ( 7 ) is arranged on a water pipe by which the deaerator ( 14 ) and the high pressure heater ( 11 ) are connected. 
     
     
         5 . The system of  claim 3 , wherein a steam inlet pipe of the high pressure heater ( 11 ) and a steam inlet pipe of the deaerator ( 14 ) communicate; and a condensate drainage pipe of the high pressure heater ( 11 ) is connected to the deaerator ( 14 ). 
     
     
         6 . The system of  claim 5  further comprising a control system, two temperature sensors ( 8 ,  10 ), and a plurality of flow control valves ( 9 ,  13 ,  21 ), wherein
 the temperature sensors and the flow control valves are connected to the control system; 
 a first temperature sensor ( 8 ) is disposed on the heat absorption member ( 5 ), and a second temperature sensor ( 10 ) is disposed on the flue between the economizer ( 3 ) and the air preheater ( 4 ) or on a water outlet pipe of the economizer ( 3 ); 
 one branch of boiler feedwater passes through a first flow control valve ( 21 ) and enters the deaerator, and another branch of boiler feedwater passes through a second flow control valve ( 9 ) and the heat release member ( 6 ) and enters the deaerator; and 
 a third flow control valve ( 13 ) is arranged on the steam inlet pipe of the high pressure heater. 
 
     
     
         7 . The system of  claim 2 , wherein
 the heat release member ( 6 ) is arranged inside the air inlet channel of the air preheater ( 4 );   the system further comprises a control system, a temperature sensor ( 8 ), and a flow control damper ( 20 );   the temperature sensor ( 8 ) and the flow control damper ( 20 ) are connected to the control system; and   the temperature sensor ( 8 ) is arranged on the heat absorption member ( 5 ), and the flow control damper ( 20 ) is arranged inside the air inlet channel of the air preheater in front of the heat release member ( 6 ) along the flow direction of inlet air.   
     
     
         8 . The system of  claim 1 , wherein the system further comprises an oil-gas separator ( 18 ); and the oil-gas separator ( 18 ) is disposed on the first circulating pipe between the heat-transfer oil heater ( 2 ) and the heat consumption device ( 19 ). 
     
     
         9 . The system of  claim 8 , wherein the oil-gas separator ( 18 ) is connected to an expansion slot ( 17 ), and the expansion slot ( 17 ) is connected to an oiling pump ( 16 ).