Waste heat recovery device for bottom slag of circulating fluidized bed boiler

Abstract

The invention discloses a waste heat recovery device for bottom slag of a circulating fluidized bed boiler. The waste heat recovery device comprises a slag discharging pipe (9) and an inclined movingbed heat exchanger (11) and is characterized in that the inclined moving bed heat exchanger (11) is integrally in an inclined form, each of an upper cross-flow section (11-16) and a lower cross-flow section (11-17) is composed of upper flow guide plates (11-10) and lower flow guide plates (11-12) and is provided with an upper air chamber and a lower air chamber, the upper air chamber (11-11) of the lower cross-flow section and the lower air chamber (11-4) of the upper cross-flow section are connected through an air chamber connecting smoke pipe (11-3), the lower air chamber (11-4) of the uppercross-flow section is provided with a bottom slag collecting box (11-15), an ash channel middle sealing and pressing section (11-9) is arranged between the two cross-flow sections, and an ash channellower sealing and pressing section (11-13) is arranged below the lower cross-flow section (11-17). According to the waste heat recovery device, recycled flue gas is adopted as a heat exchange medium,most of the heat of the bottom slag is recycled to the proper position of a hearth (1) or a tail flue (4), and therefore the physical heat loss of boiler ash is reduced, and the boiler efficiency isimproved.

Description

Technical field: [0001] The invention belongs to the technical field of circulating fluidized bed boilers, in particular to a device for cooling high-temperature bottom slag and recovering waste heat of circulating fluidized bed boilers. Background technique: [0002] The high-temperature bottom slag discharged from the circulating fluidized bed boiler contains a large amount of physical sensible heat, and it is necessary to use a suitable bottom slag cooling device for bottom slag cooling and waste heat recovery. Traditional bottom slag waste heat technologies include drum water cooling, fluidized bed air cooling, moving bed air cooling, etc. None of these traditional methods can obtain high-temperature heat exchange medium (water or air), and the waste heat utilization rate is low, accompanied by problems such as large resistance and wear. The outlet water temperature of the drum slag cooler is below 100°C, and the recovery rate of waste heat from the bottom slag is only ...

AI Technical Summary

Problems solved by technology

After the fluidized air of the fluidized bed slag cooler absorbs heat in the fluidized bed slag cooler, the hot air formed at about 300-400°C is sent back to the furnace as supplementary secondary air, but in actual operation there are gas-solid The contradiction between heat exchange and heating surface wear, as well as common problems such as slag blocking and burning coking; although the above problems have been solved to a certain extent by using a double-separation fluidized bed slag cooler (CN201010297379.9), the air in The air temperature after heat exchange in the slag cooler does not exceed 400°C, and the air volume consumption is large

The common problem of the traditional moving bed slag cooler is that it is easy to coke when air is used as the cooling medium, and the flow resistance generated by the flue gas passing through the material layer from bottom to top at one time is too large, which is difficult to apply in engineering

At present, there is still a moving bed multi-stage horizontal series gas-solid heat exchange technology (CN107013906A) to recover high-temperature bottom slag waste heat, which can increase the temperature of the working medium to about 800 °C, but the resistance is relatively large, and the adaptability to the bottom slag particle size distribution is poor. , affecting the actual application effect

Images