CN111013343A

CN111013343A - Waste incineration system

Info

Publication number: CN111013343A
Application number: CN201911298405.7A
Authority: CN
Inventors: 徐尧伟; 朱支明; 吴浩仑
Original assignee: Wuxi Huaxing East Electric Power Environmental Protection Technologies Co ltd
Current assignee: Wuxi Huaxing East Electric Power Environmental Protection Technologies Co ltd
Priority date: 2019-12-17
Filing date: 2019-12-17
Publication date: 2020-04-17

Abstract

The invention discloses a waste incineration system which is characterized by comprising a boiler, a blowing sprayer arranged in the boiler, an absorption tower communicated with the boiler, a dust remover communicated with the absorption tower through a first pipeline, an ejector communicated with the first pipeline, and a feeder communicated with the first pipeline, wherein a PLC (programmable logic controller) is respectively electrically connected with the blowing sprayer, the pressure sensor, a speed changer of the feeder, a temperature sensor arranged in front of the dust remover, a humidity sensor arranged behind the dust remover, the atomizer, the feeder and the ejector and is used for controlling the equipment to adjust the emission of sulfur dioxide, hydrogen chloride, dust, nitrogen oxides and heavy metal dioxin, and the emission of smoke is controlled automatically and perfectly.

Description

Waste incineration system

Technical Field

The invention relates to an automatic control system, in particular to a garbage incineration system for garbage incineration.

Background

Along with the continuous improvement of living standard of people, the garbage produced every day is more and more, and harmful substances discharged in smoke and ash slag generated by garbage incineration cause increasingly serious pollution to the environment. Because the components of the garbage are complex, secondary pollutants generated in the garbage incineration are mainly smoke dust, nitrogen oxides and acid gases (HCl, HF and SO)₂) CO, heavy metal dust particles (Pb, Cd, Hg) and dioxins (PCDDs, PCDFs).

The main manifestations of the harm are as follows: acid gases (HCl, HF, and SO)₂) The damage to human bodies is great, plant necrosis can be caused, and high-temperature corrosion and low-temperature corrosion on a tail heating surface are generated on a waste heat boiler superheater; the nitrogen oxide has damage to all tissues of human bodies and animals, and the concentration of the nitrogen oxide reaches a certain degree, so that the human bodies and the animals die and the living environment of the human bodies is harmed; SO (SO)₂The human body is influenced by a respiratory system, and emphysema and even death can be caused seriously; heavy metal elements contained in fine particles generated by burning garbage contain carcinogenic, mutagenic and teratogenic compounds in the pollutants; dioxin is extremely toxic, easily soluble in fat, and easily accumulated in organisms, and can cause symptoms such as skin acne, headache, deafness, melancholy, insomnia and the like, and even if a trace amount of dioxin is taken for a long time, cancer, deformity and the like can be caused.

Pollutants are generated in the process of waste incineration power generation production, and the combustion modes are different. Various types of grate incinerators are difficult to implement for removing and controlling pollutants in the incinerator due to the limitation of combustion conditions.

For SO in waste incineration tail gas₂And HCl and the like. The purification principle usually adopts alkaline solid powder CaO or stoneMortar Ca (OH)₂And neutralizing with acid gas to produce solid calcium sulfate or calcium chloride.

However, in the present stage, the indexes of main pollutants are basically manually controlled by a boiler operator, the control of the indexes is very unstable and often exceeds the standard, and the conventional technology also has simple automatic control, but the indexes are basically not ideal. In view of the above problems, it is urgently needed to develop a waste incineration system to improve the control of pollutants, so that the pollutants are prevented from exceeding standards, and the waste incineration system is easy to control and perfects the automatic control of flue gas.

Disclosure of Invention

The invention aims to provide a waste incineration system, which can realize automatic control of flue gas and avoid exceeding of pollutants.

The technical scheme adopted by the invention for solving the technical problems is as follows: a boiler generating a flue gas, a blower being disposed in the boiler; the absorption tower is communicated with the boiler, the absorption tower is respectively communicated with a material loading device and an atomizer, the material loading device is used for transmitting slurry to the absorption tower, and the atomizer is used for atomizing liquid and transmitting the liquid to the absorption tower; the dust remover is connected with the absorption tower through a first pipeline, and a pressure sensor is arranged in the dust remover; an ejector in communication with the first conduit, the ejector delivering calcium hydroxide to the first conduit; the feeding machine is communicated with the first pipeline and transmits the activated carbon to the first pipeline; and the PLC is respectively electrically connected with the blowing sprayer, the pressure sensor, a speed changer of the feeder, a temperature sensor arranged in front of the dust remover, a humidity sensor arranged behind the dust remover, the atomizer, the feeder and the ejector, controls the equipment by virtue of the PLC, adjusts the emission of sulfur dioxide, hydrogen chloride, dust, nitrogen oxide and heavy metal dioxin, and perfects the automatic control of smoke.

Further, still contain a holding vessel, its intercommunication an evaporimeter, the evaporimeter passes through a second pipeline intercommunication the boiler, the holding vessel stores aqueous ammonia, the evaporimeter transmits aqueous ammonia to the boiler.

Furthermore, the blowing device is provided with pulse blowing time, a blowing sequence and a blowing mode.

The invention relates to a waste incineration system, which has the following beneficial effects:

the PLC controller is respectively electrically connected with and transmits signals to the blowing sprayer, the pressure sensor, a speed changer of the feeder, a temperature sensor arranged in front of the dust remover, a humidity sensor arranged behind the dust remover, the atomizer, the feeder and the sprayer, the emission of sulfur dioxide, hydrogen chloride, dust, nitrogen oxide and heavy metal dioxin are automatically controlled₂、SO₃And HF and other harmful gases and the sprayed lime slurry are subjected to chemical reaction so as to achieve the purpose of removing the acid gas and realize the automatic control of the flue gas.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view showing the construction of a waste incineration system according to an embodiment of the present invention;

FIG. 2 is an electrical connection diagram of a flue gas treatment system of a waste incineration system in one embodiment of the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the embodiment of the waste incineration system, the structural schematic diagram of the waste incineration system is shown in fig. 1, and the circuit connection diagram is shown in fig. 2. The waste incineration system includes a boiler 10, an absorption tower 20, a dust collector 30, an injector 40, a feeder 50, and a PLC controller 60.

The boiler 10 is used for burning garbage, and generates flue gas in the process of burning the garbage, and pollutants contained in the flue gas mainly comprise sulfur dioxide, hydrogen chloride, dust, nitrogen oxide, heavy metal dioxin and the like. The boiler 10 is provided with a blowing device 12, and the blowing device 12 is used for blowing flue gas into an absorption tower 20 communicated with the boiler 10, so that the absorption tower 20 can treat the flue gas to reduce the content of pollutants.

The absorption tower 20 is further respectively communicated with a feeder 22 and an atomizer 24, the feeder 22 transmits lime milk to the absorption tower 20, the atomizer 24 transmits water to the absorption tower 20, and HCl and SO in flue gas₂、SO₃And HF and other harmful gases react with the sprayed lime slurry to remove acid gas.

The dust remover 30 is connected with the absorption tower 20 through a first pipeline 14, a pressure sensor 32 is arranged in the dust remover 30, and the dust remover 30 is of a low-pressure long-bag pulse structure. The dust collector 30 is composed of an upper box body, a middle box body, an inlet and outlet flue, an ash hopper, a compressed air back blowing system, a filter bag, a bag cage and the like. The flue gas of which the temperature of the fly ash and various dusts is 150 to 160 ℃ which is conveyed from the absorption tower 20 enters the dust remover 30 from the absorption tower 20. The dust collector 30 is provided with a plurality of filter bags. Smoke enters from the outside of the filter bag, various particulate matters, namely smoke dust generated by burning, lime reactant and products, condensed heavy metal, sprayed activated carbon and the like are attached to the surface of the filter bag to form a layer of filter cake, and acid gas in the smoke further reacts with excessive reactant, so that the removal efficiency of the acid gas is further improved; the active carbon also has a further adsorption effect on the surface of the filter bag. The fly ash attached to the outer surface of the filter bag is discharged into an ash bucket of the dust remover 30 through compressed air back blowing, the ash bucket is provided with a vibration device and an electric heating device, and the bins of the dust remover 30 adopt a thermal circulation air system to heat the bins, so that the fly ash can be prevented from being bonded or blocked due to moisture absorption. The leaked ash is discharged to an embedded scraper conveyor of an ash conveying system through a rotary ash discharge valve. And the flue gas after dust removal enters an induced draft fan. The ash removal of the dust remover 30 is a pulse back blowing mode, and the inlet and the outlet of each compartment are provided with valves, so that online cleaning can be realized.

The front end of the dust remover 30 is provided with a temperature sensor 34, the rear end of the dust remover 30 is provided with a humidity sensor 36, the temperature sensor 34 is vertically arranged on a flue gas pipeline and adopts PT100 thermal resistance measurement, and the humidity of the dust remover 30 is provided with data by the humidity sensor 36 through an online flue gas monitoring system. The injector 40 communicates with the first conduit 14, and the injector 40 delivers calcium hydroxide into the first conduit 14.

The feeder 50 is communicated with the first pipeline 14, and the feeder 50 transmits the activated carbon to the first pipeline 14. The activated carbon is used as an absorbent and sprayed into the flue gas to absorb the heavy metals such as dioxin, mercury and the like in the flue gas. The feeder 50 is provided with a high, low level alarm. When the high level is alarmed, an acoustic signal is sent out so as to stop filling. When the low material level is alarmed, the operator is prompted to add the active carbon in time. When the low material level is alarmed, the activated carbon is required to be added urgently.

The PLC controller 60 is electrically connected to the blowing device 12, the pressure sensor 32, a speed sensor 52 of the feeding device 50, a temperature sensor 34 disposed at the front end of the dust collector 30, a humidity sensor 36 disposed at the rear end of the dust collector 30, the atomizer 24, the loading device 22, and the injector 40, respectively, and transmits signals to the PLC controller.

The specific control thereof is as follows.

Firstly, in the automatic control of dust indexes, the pressure sensor 32 detects the pressure difference in the dust remover 30, then the pressure difference information is sent to the PLC for judgment, and when the PLC judges that the pressure difference meets the requirement, the blowing sprayer 12 is further controlled to operate to control the dust quantity, so that the index requirement of dust is met.

Specifically, the blowing device 12 is provided with a pulse blowing time, a blowing order, and a blowing mode. Wherein the blowing time can be set as the ash cleaning pulse time t0(300 ms); the ash cleaning interval time t (1-200S); a high pressure difference alarm set value (2.0 KPa); a shutdown pressure difference alarm set value (2.5 KPa); differential pressure ash removal low P1(1.1 KPa); differential pressure ash removal high value P2(1.4 KPa); differential pressure deashing long interval T1 (1-200S); the differential pressure deashing interval T2 (1-200S); differential pressure ash removal short interval T3 (1-200S); when the parameters are set, P1< P2 is satisfied; t1> T2> T3. The blowing and spraying sequence is divided into a chamber sequence and a sequence. The blowing and spraying mode is divided into a continuous mode and a differential pressure mode, wherein the continuous mode is that when the dust remover 30 needs to clean dust, the dust cleaning start button is pressed, the pulse valve of the first chamber sequentially performs blowing and dust cleaning, and after the pulse valve finishes blowing and dust cleaning, the dust cleaning of the second chamber is performed. In this way, the ash removal is performed chamber by chamber (i.e. the row sequence) until all the chamber pulse valves are completely blown with ash removal, and the whole process is called one-week ash removal, and then the second-week ash removal is performed. The differential pressure mode is that when the resistance (differential pressure) of the equipment is less than or equal to P1 (adjustable), the long interval T1 of blowing and ash removal is selected; when P1 is more than equipment resistance (differential pressure) is more than P2 (adjustable), selecting an interval T2 in blowing and ash removal; when the resistance (differential pressure) of the equipment is more than or equal to P2 (adjustable), selecting a short blowing and ash removal interval T3; when the dust remover 30 needs to clean dust, the dust cleaning start button is pressed down, and the dust is cleaned sequentially according to the differential pressure time.

When the boiler 10 is in a high-load to low-load state, the pressure in the dust collector 30 decreases, the pressure sensor 32 detects a pressure value and transmits the pressure value to the PLC controller 60, the PLC controller 60 transmits a pressure reduction signal to the blowing device 12, the pulse blowing time of the blowing device 12 increases, the blowing sequence is changed to a chamber sequence, and the blowing mode is switched to an off-line mode. When the boiler 10 is in a low-load to high-load state, the pressure sensor 32 detects a pressure value and transmits the pressure value to the PLC controller 60, the PLC controller 60 transmits a pressurization signal to the blowing device 12, the pulse time of the blowing device 12 is reduced, the blowing sequence is changed to the row sequence, and the blowing mode is switched to the on-line mode. Generally speaking, when the boiler 10 is in a low load to high load state, the amount of flue gas in the boiler 10 increases, and the amount of dust also increases, so that the blowing frequency of the blower 12 needs to be increased to absorb the generated dust, the amount of dust in the boiler 10 can be effectively detected by the above system, the state of the blower 12 is timely adjusted by the PLC controller 60, the purpose of controlling the dust emission is achieved, and the dust index is stabilized.

Secondly, in the automatic control of the heavy metal dioxin, the load in the boiler 10 is detected to judge, activated carbon is arranged in the feeding machine 50, and the feeding machine 50 is an activated carbon variable-frequency feeding machine. Specifically, as for the control of the dust, when the boiler 10 is in a high-load to low-load state, the pressure sensor 32 detects a pressure value and transmits the pressure value to the PLC controller 60, the PLC controller 60 calculates a required amount of activated carbon according to the pressure value, the PLC controller 60 transmits an acceleration signal to the feeding machine 50 according to the required amount of activated carbon, and the feeding machine 50 increases the rotation speed of the feeding machine 50 after receiving the acceleration signal, thereby increasing the transmission amount of activated carbon. In a preferred embodiment, the load of the boiler 10 can be determined by detecting the flow rate of the flue gas in the boiler 10, specifically, a flow sensor (not shown in the figure) is disposed in the boiler 10, the flow sensor is electrically connected to the PLC controller 60, when the boiler 10 is in a state from a high load to a low load, that is, the flow rate of the flue gas in the boiler 10 is increased, the flow sensor detects a flow signal and transmits the flow signal to the PLC controller 60, the PLC controller 60 calculates the required amount of the activated carbon according to the pressure value and transmits an acceleration signal to the feeder 50, the feeder 50 increases the rotation speed of the feeder 50 after receiving the acceleration signal, increases the transmission amount of the activated carbon, increases the absorption of heavy metal dioxin, and achieves the purpose of controlling the emission of heavy metal dioxin, the smoke is stabilized.

Then, in the automatic control of sulfur dioxide and hydrogen chloride, it controls the atomizer 24, the loader 22 and the injector 40 through the detection of the temperature sensor 34 and the humidity sensor 36, thereby controlling the automatic control of sulfur dioxide and hydrogen chloride. Specifically, the temperature sensor 34 is disposed at the front end of the dust collector 30, and detects a temperature value at the front end of the dust collector 30 and transmits the temperature value to the PLC controller 60, the humidity sensor 36 is disposed at the rear end of the conveying dust collector 30, and detects a humidity value at the rear end of the dust collector 30 and transmits the humidity value to the PLC controller 60, and the PLC controller calculates according to the temperature value and the humidity value, and transmits a signal to the atomizer 24, so as to control the amount of cooling water of the atomizer 24. In this embodiment, a PID controller (not shown) is included, which is electrically connected to the PLC controller 60, the PID controller being a feedback loop component commonly found in industrial control applications, which compares the collected data with a reference value and then uses this difference in calculating new input values. The PID controller is electrically connected to the dust remover 30, wherein the dust remover 30 transmits concentration values of sulfur dioxide and hydrogen chloride at an outlet end to the PID controller, the PID controller compares the concentration values of sulfur dioxide and hydrogen chloride and generates a comparison value, the PID controller transmits the comparison value to the PLC controller 60, and the PLC controller 60 sends a signal to the feeder 22 to control the amount of lime milk slurry discharged from the feeder 22. Secondly, when the temperature signal that temperature sensor 34 detected reaches a temperature setting value, and any one of the concentration values of sulfur dioxide or hydrogen chloride does not reach a concentration setting value, PLC controller 60 transmits an increase signal to sprayer 40, sprayer 40 receives behind the increase signal, adjusts the jet volume of the calcium hydroxide of sprayer 40, and then improves the efficiency of absorbing sulfur dioxide and hydrogen chloride, realizes the purpose that control sulfur dioxide and hydrogen chloride discharged, has stabilized the flue gas.

Then, in the automatic control of nitrogen oxides, the nitrogen oxides are processed by a Selective Catalytic Reduction (SCR) system and a selective non-catalytic reduction (SNCR) systemAnd (4) jointly completing. Wherein, the Selective Catalytic Reduction (SCR) is a treatment process aiming at nitrogen oxides in tail gas emission of diesel vehicles, namely, under the action of a catalyst, a reducing agent ammonia or urea is sprayed to remove NO in tail gas_xReduction to N₂And H₂And O. Selective non-catalytic reduction (SNCR) refers to the reduction of nitrogen oxides in flue gas into harmless nitrogen and water by spraying a reducing agent in a temperature window suitable for denitration reaction without the action of a catalyst.

The automatic control of nitrogen oxides is as follows, in this embodiment, the storage tank 70 is communicated with the evaporator 72, the evaporator 72 is communicated with the boiler 10 through a second pipeline 16, the storage tank 70 stores ammonia water, the evaporator 72 transmits the ammonia water to the boiler 10, and when the ammonia water escape value of the storage tank 70 reaches a set value, a warning sound is given out to inform an operator to check problem conditions. A regulating valve (not shown) is provided on the evaporator 72. The PLC controller detects the flow rate of flue gas in the boiler 10, the concentration value of nitrogen oxides at the inlet of the boiler 10 and the concentration value of nitrogen oxides at the outlet of the boiler 10, calculates to obtain a theoretical ammonia demand, the PLC controller 60 transmits the theoretical ammonia demand to the PID controller, the PID controller compares the theoretical ammonia demand with an actual ammonia demand and transmits a signal to the evaporator 72, the evaporator 72 receives the signal and then adjusts the opening of the regulating valve, the emission of ammonia is further adjusted, the nitrogen oxides are absorbed by ammonia, the purpose of controlling the emission of the nitrogen oxides is achieved, and the flue gas is stabilized. When the ammonia escape value of the flue gas in the boiler 10 reaches a set value, the PID controller transmits a signal to the evaporator 72, and the evaporator 72 locks the opening of the regulating valve, thereby protecting the equipment body and informing operators to check and maintain.

In a word, in the above waste incineration system, the PLC controller 60 is electrically connected to and transmits signals to the blowing sprayer 12, the pressure sensor 32, the one speed gear 52 of the feeder, the temperature sensor 34 disposed at the front end of the dust remover, the humidity sensor 36 disposed at the rear end of the dust remover, the atomizer 24, the feeder 22, and the ejector 40, respectively, so as to adjust the emission of sulfur dioxide, hydrogen chloride, dust, nitrogen oxide, and heavy metal dioxin, and perfect the automatic control of flue gas.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A waste incineration system, comprising:

a boiler generating a flue gas, a blower being disposed in the boiler;

the absorption tower is communicated with the boiler, the absorption tower is respectively communicated with a material loading device and an atomizer, the material loading device is used for transmitting slurry to the absorption tower, and the atomizer is used for atomizing liquid and transmitting the liquid to the absorption tower;

the dust remover is connected with the absorption tower through a first pipeline, and a pressure sensor is arranged in the dust remover;

an ejector in communication with the first conduit, the ejector delivering calcium hydroxide to the first conduit;

the feeding machine is communicated with the first pipeline and transmits the activated carbon to the first pipeline;

and the PLC is respectively and electrically connected with the blowing sprayer, the pressure sensor, a speed changer of the feeding machine, a temperature sensor arranged in front of the dust remover, a humidity sensor arranged behind the dust remover, the atomizer, the feeding device and the ejector and transmits signals to the blowing sprayer, the pressure sensor, the speed changer of the feeding machine, the humidity sensor arranged behind the dust remover, the atomizer, the feeding device and the ejector.

2. The waste incineration system of claim 1, further comprising a storage tank in communication with an evaporator, the evaporator in communication with the boiler through a second conduit, the storage tank storing ammonia, the evaporator delivering ammonia to the boiler.

3. The waste incineration system according to claim 1, wherein a warning sound is given when an ammonia escape value of the storage tank reaches a set value.

4. Waste incineration system according to claim 1, characterised in that the blow-sprayers are provided with a pulsed blow-time, a blow-sequence and a blow-pattern.