A sludge incineration waste heat utilization system

Abstract

A sludge incineration waste heat utilization system relates to the field of environmental protection technology. The high-temperature flue gas at the outlet of the incinerator of the system of the present invention enters the high-temperature waste heat boiler, the air preheater and the low-temperature waste heat boiler in sequence. The low-temperature feed water receives the heat of the low-temperature flue gas through the low-temperature waste heat boiler to form saturated steam. Part of the saturated steam is used for the dryer to evaporate the moisture in the wet sludge, and the other part of the saturated steam enters the high-temperature waste heat boiler to absorb high-quality heat to form high-temperature steam. The high-temperature steam enters the steam turbine to work and produce electricity. The air preheater arranged between the two-stage waste heat boiler heats the compressed cold air into high-temperature fluidizing air and sends it to the incinerator. The steam after the steam turbine works is condensed into condensed water through the air cooler, and is mixed with the condensed water of the dryer and sent to the low-temperature waste heat boiler as feed water to form a closed cycle. The present invention adopts a two-stage waste heat boiler to make more full use of the flue gas heat, while meeting the quality requirements of the air required by the incinerator and the steam required by the dryer.

Description

Technical Field

[0001] The invention relates to the technical fields of sludge incineration disposal, energy utilization and environmental protection, in particular to an energy system that efficiently utilizes sludge incineration heat. Background Art

[0002] Sludge drying and incineration is an efficient and harmless technology and a relatively environmentally friendly method of sludge disposal. With the increasingly stringent environmental protection requirements of the country, sludge drying and incineration projects have developed rapidly in China in recent years.

[0003] In the conventional sludge drying and incineration project, the flue gas at the outlet of the incinerator first enters the air preheater to generate high-temperature air, and then enters the waste heat boiler after passing through the air preheater, and the waste heat boiler generates steam for the dryer. This method does not maximize the use of the heat in the flue gas, there is still a problem of energy waste, and the output of the system still needs to be increased. Summary of the invention

[0004] In view of the above shortcomings in the prior art, the present invention aims to provide a sludge incineration waste heat utilization system, which uses a two-stage waste heat boiler to more fully utilize the flue gas heat and at the same time meets the quality requirements of the air required by the incinerator and the steam required by the dryer.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is implemented in the following manner:

[0006] A sludge incineration waste heat utilization system, which includes an incinerator. Its structural feature is that the high-temperature flue gas at the outlet of the incinerator enters the high-temperature waste heat boiler, the air preheater and the low-temperature waste heat boiler in sequence. The low-temperature feed water receives the heat of the low-temperature flue gas through the low-temperature waste heat boiler to form saturated steam. Part of the saturated steam is used for the dryer to evaporate the moisture in the wet sludge, and the other part of the saturated steam enters the high-temperature waste heat boiler to absorb high-quality heat to form high-temperature steam. The high-temperature steam enters the steam turbine to work and produce electricity. The air preheater arranged between the two-stage waste heat boiler heats the compressed cold air into high-temperature fluidizing air and sends it to the incinerator. The steam after the steam turbine works is condensed into condensed water through the air cooler, and is mixed with the condensed water of the dryer and sent to the low-temperature waste heat boiler as feed water to form a closed cycle.

[0007] Due to the adoption of the above structure, the present invention can improve the existing flue gas waste heat utilization system while meeting the fluidizing air temperature of the sludge incinerator and the required steam quality requirements of the dryer, without affecting the existing system performance. At the same time, compared with the existing technology, it has the following advantages and beneficial effects:

[0008] 1. The system of the present invention is equipped with a high-temperature waste heat boiler, a small steam turbine and an air cooler, which requires less equipment and occupies a small area, but the benefits of electric energy output are obvious.

[0009] 2. The air preheater is set between the two-stage waste heat boilers, using lower-quality flue gas to heat the cold air and use lower-quality energy to meet the air temperature requirements of the sludge incinerator.

[0010] 3. The flue gas in the high temperature section is used to produce high temperature steam for work, and the saturated steam produced in the low temperature section meets the needs of the dryer, thereby increasing the heat utilization rate of the flue gas.

[0011] 4. The condensate from the condenser is mixed with the condensate from the dryer and supplied to the waste heat boiler as feed water. Compared with the conventional dryer condensate as feed water, this water supply method of the present invention can reduce the exhaust temperature of the waste heat boiler and make full use of the waste heat of the flue gas.

[0012] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the present invention. DETAILED DESCRIPTION

[0014] See also Figure 1 The sludge incineration waste heat utilization system of the present invention comprises an incinerator 15, a high-temperature waste heat boiler 16, an air preheater 17, a low-temperature waste heat boiler 18 and a dryer 21 connected in sequence. The low-temperature saturated steam diverted from the steam side of the high-temperature waste heat boiler 16 is connected to the dryer 21 and the low-temperature waste heat boiler 18 respectively after passing through the steam turbine 19 and the air cooler 20. The steam turbine 19 performs work and produces electrical energy. The low-temperature waste heat boiler 18 sends part of the saturated steam after heating the feed water to the dryer 21, and the other part to the high-temperature waste heat boiler 16. The air preheater 17 heats the compressed cold air into fluidizing air and sends it to the incinerator 15.

[0015] When the present invention is in operation, the dried sludge enters the sludge incinerator 15, and the sludge is completely incinerated under the circulation of hot air and heat carrier. The flue gas after incineration first enters the high-temperature waste heat boiler 16. The steam side of the high-temperature waste heat boiler 16 inputs saturated steam heated by the low-temperature waste heat boiler 18. The steam becomes superheated steam after heating and enters the steam turbine 19 to do work. The flue gas from the high-temperature waste heat boiler 16 enters the air preheater 17 to heat the external cold air, and the cold air is sent to the sludge incinerator 15 as fluidizing air after heating. The flue gas from the air preheater 17 enters the low-temperature waste heat boiler 18, heats the feed water of the low-temperature waste heat boiler 18 and becomes saturated steam for discharge. The discharged saturated steam is divided into two streams, one part is used for the dryer 21, and the other part is passed into the high-temperature waste heat boiler 16. The steam generated by the steam turbine 19 after working to produce electricity is condensed by the air cooler 20, and the condensed water is mixed with the hot water at the outlet of the dryer 21 and sent to the low-temperature waste heat boiler 18 as feed water.

Claims

1. A sludge incineration waste heat utilization system, comprising an incinerator (15), characterized in that: The high-temperature flue gas at the outlet of the incinerator (15) sequentially enters the high-temperature waste heat boiler (16), the air preheater (17) and the low-temperature waste heat boiler (18). The low-temperature feed water receives the heat of the low-temperature flue gas through the low-temperature waste heat boiler (18) to form saturated steam. A part of the saturated steam is used for the dryer (21) to evaporate the moisture in the wet sludge. The other part of the saturated steam enters the high-temperature waste heat boiler (16) to absorb high-quality heat to form high-temperature steam. The high-temperature steam enters the steam turbine (19) to perform work and generate electric energy. The air preheater (17) arranged between the two-stage waste heat boilers heats the compressed cold air into high-temperature fluidizing air and sends it to the incinerator (15). The steam after the steam turbine (19) performs work is condensed into condensed water through the air cooler (20). After being mixed with the condensed water of the dryer (21), it is sent to the low-temperature waste heat boiler (18) as feed water to form a closed cycle.

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