Recovery method of waste heat of flue gas

Abstract

The invention discloses a recovery method of waste heat of flue gas, which comprises the following steps that: flue gas with a temperature of 1050 to 1150 DEG C from a radiation chamber sequentially and respectively exchanges heat with a heat exchange medium with a temperature of 480 to 520 DEG C, a heat exchange medium with a temperature of 450 to 490 DEG C and a material with a temperature of 280 to 320 DEG C; the heat exchange among high-temperature air, a material with a temperature of 250 to 320 DEG C and low-temperature air is carried out, and the flue gas is cooled to 130 to 160 DEG C and is discharged to atmosphere through a chimney; and pre-heated air is used for supplying oxygen to a heating furnace. The recovery method overcomes the defect of the waste of fuel caused by steam generated by pre-heating the flue gas in the traditional technical field.

Description

technical field [0001] The invention belongs to the field of petroleum refining, and in particular relates to a waste heat recovery process of a reformer flue gas of a hydrogen production device. technical background [0002] As we all know, the petrochemical industry is a large energy consumer. With the implementation of the national energy conservation general policy of "emphasizing both resource development and conservation, and putting conservation first", energy conservation and consumption reduction in petroleum and chemical plants have attracted increasing attention. At the same time, in a large-scale comprehensive refinery, energy saving and consumption reduction are often limited only from the perspective of one or several devices. From the point of view of the whole plant, the heat combination between devices can be realized, the abundant heat between devices can be fully utilized, and the abundant heat of one device can be used for devices that need heat, so as to...

AI Technical Summary

Problems solved by technology

However, the evaporation section of this process uses a natural circulation water pipe type flue gas waste boiler to generate medium-pressure steam. During the operation of the device, due to the fixed area of ​​the heat exchange pipe, when the load changes, the heat load cannot be adjusted, and the waste heat at the low temperature of the flue gas cannot be adjusted. Fully utilized, the flue gas exhaust temperature is too high, sometimes as high as 200°C or more, which may cause the induced draft fan to stop, the device to stop production, and cause economic losses; From the point of view of the whole plant, due to the centralized steam production system of medium pressure boilers, 4.0~4.4MPa(g) medium pressure steam is generally relatively rich, and compared with fuel gas, it is more economical to use coal to produce steam, so Can not be reasonable, the hydrogen production unit does not need to export medium-pressure steam