Sludge pre-drying and direct co-firing system suitable for circulating fluidized bed boilers

Abstract

The invention discloses a sludge pre-drying and direct-furnace mixing and burning system suitable for a circulating fluidized bed boiler, comprising a wet sludge bin, pre-drying equipment, a dry sludge storage bin, a coal conveying belt, a sludge distribution belt, a sludge bin in front of a furnace, a rotary plugging removal device, a furnace feed spiral, a material drop pipe and a circulating fluidized bed boiler; the outlet of the wet sludge bin is connected to the inlet of the circulating fluidized bed boiler via the pre-drying equipment, the dry sludge storage bin, the coal conveying belt, the sludge distribution belt, the sludge bin in front of a furnace, the rotary plugging removal device, the furnace feed spiral and the material drop pipe in sequence, and the system can achieve the purpose of simultaneously treating wet sludge with a moisture content of 70% to 85% and wet sludge with a moisture content of 50% to 65%, and the treatment cost is low.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection and relates to a sludge pre-drying and direct-furnace mixing and combustion system suitable for a circulating fluidized bed boiler. Background Art

[0002] In recent years, the problem of "sludge siege" has become more and more serious, and the development of sludge disposal technology is urgent. Compared with traditional sanitary landfill, agricultural utilization, marine disposal, building material utilization, etc., sludge incineration is the most "thorough" sludge treatment method, with outstanding advantages such as fast processing speed, high reduction degree, and resource recycling.

[0003] For sewage treatment plants, the use of sludge incineration technology requires the construction of incinerators and tail gas purification systems, which requires large project investments, high operating costs, and poor economic efficiency. Coal-fired boilers are natural sludge incinerators, especially circulating fluidized bed boilers, which have many advantages such as wide fuel adaptability, high combustion efficiency, and low pollutant emissions.

[0004] According to the sludge blending method, sludge incineration can be divided into two types: wet sludge directly fed into the furnace for blending and wet sludge dried for incineration. The sludge drying and incineration technology is to dry the wet sludge with a moisture content of about 80% to a moisture content of less than 40% through a newly built sludge drying system before incineration. The traditional wet sludge direct blending technology, for wet sludge with a moisture content below 65%, uses the power plant's coal transportation system to mix it with coal and then feed it into the boiler; for wet sludge with a moisture content above 70%, because the sludge is in a viscous slurry state, it can only be fed into the boiler using a special sludge screw pump.

[0005] Conventional wet sludge direct combustion system can only process sludge with a moisture content range (such as 50% to 65% or 70% to 85%). In the current engineering application field, direct combustion technology is generally used for wet sludge with a moisture content of 50% to 65%. For wet sludge with a moisture content of 70% to 85%, the wet sludge is generally dried to a moisture content of less than 40% through a sludge drying system before entering the furnace for incineration. At this time, a new sludge drying system is required, and the drying system equipment investment is large, the heat source energy consumption is large, and the operating cost is high. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a sludge pre-drying and direct-to-furnace co-combustion system suitable for a circulating fluidized bed boiler. The system can simultaneously process wet sludge with a moisture content of 70% to 85% and wet sludge with a moisture content of 50% to 65%, and the processing cost is low.

[0007] To achieve the above-mentioned purpose, the sludge pre-drying and direct-into-furnace co-combustion system suitable for a circulating fluidized bed boiler of the present invention comprises a wet sludge bin, a pre-drying device, a dry sludge storage bin, a coal conveyor belt, a sludge distribution belt, a sludge bin in front of the furnace, a rotary clearing device, a furnace feeding spiral, a material dropping pipe and a circulating fluidized bed boiler;

[0008] The outlet of the wet sludge bin is connected to the inlet of the circulating fluidized bed boiler via the pre-drying equipment, dry sludge storage bin, coal conveyor belt, sludge distribution belt, sludge bin in front of the furnace, rotary clearing device, furnace inlet spiral and drop pipe.

[0009] It also includes a sludge pre-drying workshop building, in which the wet sludge bin, pre-drying equipment and dry sludge storage bin are all located in the sludge pre-drying workshop building.

[0010] The air outlet of the sludge pre-drying workshop is connected to the circulating fluidized bed boiler through a negative pressure fan and a booster fan.

[0011] The wet sludge bin is connected with the pre-drying equipment via the wet sludge conveying equipment.

[0012] The pre-drying equipment is connected with the dry sludge storage bin via the dry sludge discharging and conveying device.

[0013] The dry sludge storage bin is connected to the coal conveyor belt via the dry sludge conveying equipment.

[0014] The pre-drying equipment dries the moisture content of wet sludge from 70% to 85% to 50% to 65%. Plate and frame filter press, high-pressure belt filter press or other mechanical dryers can be used.

[0015] The present invention has the following beneficial effects:

[0016] The sludge pre-drying and direct-into-furnace co-combustion system suitable for a circulating fluidized bed boiler of the present invention is used to dry wet sludge with a moisture content of 70% to 85% sent from a sewage treatment plant to a moisture content of 50% to 65% through a pre-drying device, and then sent to a dry sludge storage bin together with sludge with a moisture content of 50% to 65% directly sent from the sewage treatment plant. Then, the sludge is incinerated and disposed of through a drying sludge bin system and a sludge incineration system, so as to achieve the purpose of simultaneously treating wet sludge with a moisture content of 70% to 85% and wet sludge with a moisture content of 50% to 65%. The system is simple, has high operating reliability, and has low processing cost.

[0017] Furthermore, the wet sludge silo, pre-drying equipment and dry sludge storage silo are all located in the sludge pre-drying workshop building. The air outlet of the sludge pre-drying workshop building is connected to the circulating fluidized bed boiler through a negative pressure fan and a booster fan. The odor generated during the treatment process is directly sent into the circulating fluidized bed boiler for combustion, so as to achieve odor-free emissions in the entire process of sludge disposal in the power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention.

[0019] Among them, 1 is a wet sludge bin, 2 is a wet sludge conveying equipment, 3 is a pre-drying equipment, 4 is a dry sludge discharging and conveying device, 5 is a dry sludge storage bin, 6 is a dry sludge conveying equipment, 7 is a coal conveyor belt, 8 is a sludge distribution belt, 9 is a sludge bin in front of the furnace, 10 is a rotary clearing device, 11 is a furnace inlet spiral, 12 is a drop pipe, 13 is a circulating fluidized bed boiler, 14 is a negative pressure fan, 15 is a booster fan, and 16 is a sludge pre-drying workshop building. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0021] refer to Figure 1 The sludge pre-drying and direct-to-furnace co-combustion system suitable for a circulating fluidized bed boiler of the present invention comprises a wet sludge bin 1, a pre-drying device 3, a dry sludge storage bin 5, a coal conveyor belt 7, a sludge distribution belt 8, a sludge bin in front of a furnace 9, a rotary clearing device 10, a furnace inlet spiral 11, a material drop pipe 12 and a circulating fluidized bed boiler 13; the outlet of the wet sludge bin 1 is connected to the inlet of the circulating fluidized bed boiler 13 via the pre-drying device 3, the dry sludge storage bin 5, the coal conveyor belt 7, the sludge distribution belt 8, the sludge bin in front of a furnace 9, the rotary clearing device 10, the furnace inlet spiral 11 and the material drop pipe 12 in sequence.

[0022] The present invention further comprises a sludge pre-drying workshop building 16 , wherein the wet sludge bin 1 , the pre-drying equipment 3 and the dry sludge storage bin 5 are all located in the sludge pre-drying workshop building 16 .

[0023] Specifically, the air outlet of the sludge pre-drying workshop building 16 is connected to the circulating fluidized bed boiler 13 via the negative pressure fan 14 and the booster fan 15; the wet sludge bin 1 is connected to the pre-drying equipment 3 via the wet sludge conveying equipment 2; the pre-drying equipment 3 is connected to the dry sludge storage bin 5 via the dry sludge discharging conveying device 4; the dry sludge storage bin 5 is connected to the coal conveyor belt 7 via the dry sludge conveying equipment 6.

[0024] The wet sludge pre-drying process is as follows: the wet sludge with a moisture content of 70% to 85% temporarily stored in the wet sludge bin 1 is transported to the pre-drying equipment 3 through the wet sludge conveying equipment 2, and then the sludge is dried to a moisture content of 50% to 65% by the pre-drying equipment 3, and then sent to the dry sludge storage bin 5 by the dry sludge discharging conveying device 4.

[0025] The dried sludge storage process is as follows: the dry sludge with a moisture content of 50% to 65% temporarily stored in the dry sludge storage bin 5 is transported to the coal conveyor belt 7 through the dry sludge conveying equipment 6, and is sent to the front of the furnace using the existing coal conveyor belt 7, and then sent to the sludge bin 9 in front of the furnace through the sludge distribution belt 8.

[0026] The sludge incineration system process is as follows: the sludge in the sludge bin 9 in front of the furnace enters the furnace inlet spiral 11 through the rotary clearing device 10 and then enters the circulating fluidized bed boiler 13 through the drop pipe 12 for incineration.

[0027] The odor treatment process is as follows: a negative pressure fan 14 is used to extract the odor from the wet sludge bin 1, the wet sludge conveying equipment 2, the pre-drying equipment 3, the dry sludge discharging and conveying device 4, the dry sludge storage bin 5, the dry sludge conveying equipment 6 and the sludge pre-drying workshop 16, and then the odor is sent to the circulating fluidized bed boiler 13 for incineration through the booster fan 15 through the odor conveying pipeline.

[0028] There are two sources of sludge with a moisture content of 50% to 65% in the dry sludge storage bin 5. One is the sludge produced by drying wet sludge with a moisture content of 70% to 85% through the pre-drying equipment 3, and the other is the sludge with a moisture content of 50% to 65% directly delivered by a tanker truck from a sewage treatment plant.

[0029] The working principle of the present invention is as follows: wet sludge with a moisture content of 70% to 85% sent from a sewage treatment plant is dried to a moisture content of 50% to 65% through a pre-drying device 3, and then sent to a dry sludge storage bin 5 together with sludge with a moisture content of 50% to 65% directly sent from the sewage treatment plant, and then the sludge is incinerated and disposed of through a drying sludge storage system and a sludge incineration system, and the odor generated during the sludge disposal process is sent to a boiler for incineration through the odor treatment system.

[0030] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Those skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A sludge pre-drying and direct-into-furnace co-combustion system suitable for a circulating fluidized bed boiler, characterized in that: It comprises a wet sludge bin (1), a pre-drying device (3), a dry sludge storage bin (5), a coal conveyor belt (7), a sludge distribution belt (8), a sludge bin in front of a furnace (9), a rotary blockage clearing device (10), a furnace inlet spiral (11), a material drop pipe (12) and a circulating fluidized bed boiler (13); The outlet of the wet sludge bin (1) is connected to the inlet of the circulating fluidized bed boiler (13) via the pre-drying device (3), the dry sludge storage bin (5), the coal conveyor belt (7), the sludge distribution belt (8), the sludge bin in front of the furnace (9), the rotary blockage clearing device (10), the furnace inlet spiral (11) and the drop pipe (12) in sequence; It also includes a sludge pre-drying workshop building (16), wherein the wet sludge bin (1), the pre-drying equipment (3) and the dry sludge storage bin (5) are all located in the sludge pre-drying workshop building (16); The air outlet of the sludge pre-drying workshop (16) is connected to the circulating fluidized bed boiler (13) via a negative pressure fan (14) and a booster fan (15); The wet sludge bin (1) is connected to the pre-drying device (3) via the wet sludge conveying device (2); The wet sludge temporarily stored in the wet sludge bin (1) with a moisture content of 70% to 85% is transported to the pre-drying device (3) through the wet sludge conveying device (2), and then the sludge is dried to a moisture content of 50% to 65% by the pre-drying device (3), and then transported to the dry sludge storage bin (5) by the dry sludge discharging conveying device (4); The drying sludge storage process is as follows: the dry sludge with a moisture content of 50% to 65% temporarily stored in the dry sludge storage bin (5) is transported to the coal conveyor belt (7) through the dry sludge conveying equipment (6), and then transported to the front of the furnace by using the existing coal conveyor belt (7), and then transported to the sludge bin (9) in front of the furnace by the sludge distribution belt (8); The sludge with a moisture content of 50% to 65% in the dry sludge storage bin (5) has two sources: one is the sludge produced by drying wet sludge with a moisture content of 70% to 85% through the pre-drying device (3); the other is the sludge with a moisture content of 50% to 65% directly delivered by tank trucks from the sewage treatment plant.

2. The sludge pre-drying and direct-into-furnace co-combustion system suitable for circulating fluidized bed boilers according to claim 1 is characterized in that: The pre-drying equipment (3) is connected to the dry sludge storage bin (5) via the dry sludge discharging and conveying device (4).

3. The sludge pre-drying and direct-into-furnace co-combustion system suitable for circulating fluidized bed boilers according to claim 1 is characterized in that: The dry sludge storage bin (5) is connected to the coal conveyor belt (7) via the dry sludge conveying equipment (6).

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