| 摘要 |
1,084,896. Regulating waste heat boilers. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. Nov. 29. 1965 [Nov. 30, 1964],. No. 50590/65. Headings F4A and F4B. Waste gases from a furnace 1 used for heating a medium such as oil in pipes 2. flow out through duct 13 to waste heat boiler 14 having an auxiliary burner 35 and containing an economizer 15 evaporating sections 20, 25 and superheater 28. Feed pump 17 forces water through duct 16, economizer 15 and duct 18 to the steam-water separator 19, from whence circulating pump 22 forces it through duet 21 and the evaporating sections 20, 25, and duct 26 to the steam-water separator 19, the steam passing via duct 27 to superheater 28 and outlet duct 29. Increase or decrease in steam demand as measured by manometer 30 in line 29, is met by opening or closing valve 23, in duct 21 leading to the evaporating section 20, through the controller 31. This reduces or increases the hot water flow to air heater 32 in parallel with valve 23, disposed in the combustion air inlet duet 6 to the gas or oil fired furnace 1 so reducing or increasing the degree of air preheating and consequently the heat input to the furnace 1. The resultant drop or rise in the outlet temperature of the medium being heated as measured by element 9 causes controller 10 to actuate valve 8 in fuel supply line 7 to increase or decrease the fuel supply to furnace 1 to maintain the heated medium outlet temperature constant. The supply valve 8 may also be actuated by controller 12 under the influence of variations in the inlet combustion air temperature measured by element 11. The increase or decrease in the fuel supply causes an increase or decrease in the volume of waste gases passing to boiler 14, and so provides bigger or smaller heat imput to the boiler to meet the variation in steam demand. In modifications (Figs. 2 and 3, not shown) the valve controlling the hot water flow through the air heater is disposed in the line to the air heater, the return line from the air heater bypassing the evaporating sections. |
