Small-scale domestic waste incinerator and using method thereof

Abstract

The present invention belongs to the technical field of the incinerator equipment, and particularly relates to a small-scale domestic waste incinerator and a using method thereof. The incinerator includes a drying pyrolysis chamber and a combustion chamber arranged over a grate assembly of the waste incinerator, a secondary combustion chamber is in communication with the upper portion of the combustion chamber, a position in proximity to the upper portion of the combustion chamber is provided with a pyrolysis gas nozzle, a drying pyrolysis chamber outlet flue duct with an induced draft fan is installed at a position in proximity to the upper end of the drying pyrolysis chamber, the drying pyrolysis chamber outlet flue duct is in connection with a pyrolysis gas nozzle through a condenser, a diversion chamber is situated between the same side of the combustion chamber and the secondary combustion chamber and the drying pyrolysis chamber, and the drying pyrolysis chamber is longitudinally provided with a flue gas nozzle, which is in communication with the diversion chamber. A secondary combustion chamber outlet flue and a circulating flue are arranged at the top of the secondary combustion chamber, the circulating flue is in communication with the diversion chamber, and a guide plate configured to regulate the quantity of the flue gas is arranged at the top of the secondary combustion chamber. In the present invention, the moisture content of the waste entering the incinerator is reduced, the heat value for the waste is increased, so that the requirement of 850 °C for at least 2 seconds in the incinerator can be satisfied without supplementing fuel, and the homogenization of the waste is completed before entering the furnace, which ensures that the temperature and the load fluctuation of the incinerator is relative little, the waste combustion is sufficient, and the ignition loss of the slags is low.

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of waste incinerators, and in particular to a small-scale domestic waste incinerator and a using method thereof.BACKGROUND

[0002] Currently, waste incineration technology is relatively mature, primarily applied in large-scale facilities designed for centralized urban waste treatment. However, in remote and island areas with scattered populations and low waste generation, transportation costs are prohibitively high, making centralized incineration impractical. As a result, decentralized, small-scale, on-site waste disposal solutions suitable for rural, township, and island settings represent a key direction for future development. This growing need has driven strong demand for small-scale domestic waste incinerators.

[0003] The main problems of the technology of the incinerator for the small-scale domestic waste incinerator are as follows. (1) The domestic waste has a high moisture content and low heat value, which results in incomplete combustion and requires a large quantity of additional fuel.

[0004] Domestic waste typically has a moisture content exceeding 50% and a consequently low calorific value. The direct incineration of such high-moisture waste results in insufficient combustion temperatures and incomplete combustion, as evidenced by a high loss on ignition. To maintain the legally required furnace temperature of 850 °C for at least 2 seconds, a substantial amount of auxiliary fuel must be introduced, leading to significantly elevated operational costs.

[0005] (2) The amount of domestic waste to be treated is small, and its composition is highly variable, leading to operational difficulties.

[0006] The small treatment scale and highly variable composition of the waste pose significant challenges to the incinerator and auxiliary systems, hindering stable operation and adjustment.

[0007] (3) The high concentration of pollutants in the flue gas makes compliance with emission standards challenging.

[0008] Due to low combustion temperatures and high initial pollutant concentrations, many small-scale waste incineration systems lack online flue gas monitoring. Furthermore, ensuring emissions compliance under these conditions results in prohibitively high operating costs.

[0009] (4) The low volume of flue gas presents a significant challenge for the effective and economical utilization of its waste heat.

[0010] Small-scale waste incineration systems produce a limited volume of flue gas, which often makes waste heat recovery impractical. Consequently, rapid quenching is typically employed for gas conditioning. This method, however, is highly inefficient. It not only wastes substantial thermal energy but also introduces excessive moisture into the flue gas. The resulting severe condensation readily leads to bag clogging in the filtration system.

[0011] (5) Conventional incinerators are typically bulky, structurally complex, and space-consuming, resulting in high operational and maintenance costs.

[0012] Existing small-scale waste incinerators still adopt the structural design of large-scale systems, comprising drying, combustion, and ash sections with a complex grate assembly. This results in equipment that is overly large, space-consuming, structurally complicated, and costly.

[0013] Patent CN118189179B discloses a pyrolysis gasification small-scale domestic waste incinerator and process. It positions a pyrolysis chamber at the incinerator's front end and introduces hot flue gas into it to dry and pyrolyze the waste, thereby reducing moisture and increasing calorific value. Nevertheless, this method faces several challenges: precise control over the volume and uniform distribution of the incoming hot flue gas is difficult, leading to inconsistent waste drying. Moisture released during drying remains in the flue gas, raising its humidity and promoting condensation and bag clogging. Furthermore, the direct connection between the pyrolysis and combustion chambers causes excessive bottom temperatures and allows excess air, making the waste prone to open combustion and complicating reaction and temperature control.

[0014] Patent CN108980847B discloses a waste treatment process utilizing a drying layer and a carbonization layer at the incinerator's front end, using hot flue gas and furnace radiation for pre-treatment. While this method reduces waste moisture and increases calorific value, it suffers from several drawbacks. Structurally, the drying and carbonization grates are complex, with the latter operating at high temperatures that make it prone to damage. Operationally, the direct connection to the combustion chamber leads to excessive temperatures and air ingress in the carbonization layer, causing unwanted combustion and making process control difficult. Thermally, the limited rise and uncontrolled flow of hot flue gas result in low drying efficiency, as the drying layer relies primarily on radiant heat.

[0015] Patent CN220852160U discloses a garbage incinerator with a pyrolysis chamber positioned above the combustion chamber, relying solely on radiant heat for drying and pyrolysis. This design exhibits significant limitations: its sole reliance on radiant heat results in low drying efficiency and an inability to effectively control the drying rate. Furthermore, the process lacks the adjustability to handle variations in waste moisture, calorific value, and composition. Structurally, the horizontal arrangement of the pyrolysis chamber impedes waste flow, and the use of spiral feeding equipment in this configuration is prone to blockages.

[0016] In summary, most existing small-scale domestic waste incinerators inherit the structural design and processes of large-scale systems, leading to issues such as incomplete combustion, operational instability, non-compliant flue gas emissions, unutilized waste heat, and high costs. While a minority of designs incorporate a pre-combustion drying / pyrolysis chamber to reduce moisture and enhance calorific value, thereby improving combustion stability, and these chambers are often structurally complex, operationally challenging, and inefficient. Their direct connection to the combustion chamber also risks unwanted combustion and overheating within the chamber itself. Consequently, there is a clear need for a novel small-scale incinerator, particularly one equipped with an adaptive control strategy, to effectively handle waste characterized by low throughput, high moisture, low calorific value, and highly variable composition.SUMMARY

[0017] The technical objectives of the present invention are to solve the problems of the small-scale domestic waste incinerator, such as an incomplete waste combustion, a low combustion temperature, high auxiliary fuel demand, and non-compliant pollutant emissions, due to a high water content, a low heat value, and a large fluctuation of components. Therefore, it is necessary to develop a small-scale waste incinerator suitable for treating the waste with a high moisture content, a low heat value, and a large fluctuation of components, and a control method thereof.

[0018] In order to achieve the above objectives, the following technical solutions are adopted in the present invention.

[0019] Provided is a small-scale domestic waste incinerator. The incinerator comprises a drying pyrolysis chamber and a combustion chamber arranged over a grate assembly of the waste incinerator, the drying pyrolysis chamber is disposed at an upstream section of the grate assembly, and the combustion chamber is disposed at a downstream section of the grate group.

[0020] The drying pyrolysis chamber is vertically oriented, an upper end of the drying pyrolysis chamber is a waste inlet, and a lower end of the drying pyrolysis chamber is a waste outlet, and one part of the grate assembly is covered by the waste outlet of the drying pyrolysis chamber.

[0021] The grate assembly is enclosed by the combustion chamber, and a secondary combustion chamber is in communication with an upper portion of the combustion chamber, and a pyrolysis gas nozzle is mounted on a side wall of the combustion chamber in proximity to an upper section of the drying pyrolysis chamber.

[0022] A drying pyrolysis chamber outlet flue duct with an induced draft fan is provided on a side wall of the drying pyrolysis chamber in proximity to an upper end of the drying pyrolysis chamber, and the drying pyrolysis chamber outlet flue duct is in connection with the pyrolysis gas nozzle through a condenser.

[0023] A diversion chamber is situated between a same side of the combustion chamber and the secondary combustion chamber and one side of the drying pyrolysis chamber, a position of the diversion chamber is lower than a position of a circulating flue duct of the secondary combustion chamber, the diversion chamber is sealed at a bottom end, and a top end of the diversion chamber is a flue gas inlet, a side part of the drying pyrolysis chamber is provided with a plurality of flue gas nozzles along a longitudinal direction, and the flue gas nozzles are in communication with the diversion chamber.

[0024] A secondary combustion chamber outlet flue duct and a circulating flue duct are respectively arranged on both sides of a top part of the secondary combustion chamber, the circulating flue duct is in communication with the flue gas inlet of the diversion chamber, and a guide plate configured to regulate quantities of flue gas introduced into the secondary combustion chamber outlet flue duct and the circulating flue duct is installed on the top part of the secondary combustion chamber.

[0025] As one further preferred solution, calibers of the plurality of flue gas nozzles are sequentially increased from top to bottom.

[0026] As one further preferred solution, three sealing gates are arranged at the waste inlet of the drying pyrolysis chamber, and a switch plate is arranged at the waste outlet.

[0027] As one further preferred solution, the grate assembly is formed by slidable grates and fixed grates, and the slidable grates and the fixed grates are arranged in an alternating sequence.

[0028] As one further preferred solution, the waste outlet of the drying pyrolysis chamber is sealed by a first-stage slidable grate of the grate assembly, and the slidable grate is further taken as a feeding grate.

[0029] Further provided is a method for using a small-scale domestic waste incinerator, the method includes following steps.

[0030] In Step 1, the waste is added to the drying pyrolysis chamber by a bucket elevator after being sorted and crushed.

[0031] In Step 2, high-temperature flue gas produced by a combustion in the secondary combustion chamber is introduced through the plurality of flue gas nozzles on the side wall of the drying pyrolysis chamber, a drying and a pyrolysis reaction are performed on the waste in the drying pyrolysis chamber under a heating of the high-temperature to generate water vapor and a small quantity of combustible gas, and the generated water vapor and the small quantity of combustible gas are introduced into the high-temperature flue gas and discharged from the drying pyrolysis chamber outlet flue duct.

[0032] In Step 3, dried waste is fallen from the waste outlet onto the grate assembly, the waste are transported downstream with a pushing of the slidable grate in the grate assembly, and a turning-over is completed when the waste is passed through the fixed grate in the grate assembly and fallen off, bottom slags produced by a combustion of the waste is discharged from a slag outlet of the grate assembly, and the flue gas produced by the combustion is introduced into the combustion chamber.

[0033] In Step 4, a primary air is supplied from beneath the gate assembly into the combustion chamber, and a secondary air is introduced to the combustion chamber through an opening of a furnace rear arch, and under an action of the secondary air, the flue gas is completely mixed to ensure a complete combustion.

[0034] In Step 5, the flue gas produced by the pyrolysis chamber is condensed by the condenser, and the dry flue gas is recirculated into the combustion chamber via the pyrolysis gas nozzle to completely combust a small quantity of combustible gas, and condensed water produced by the condenser can be utilized as makeup water for a quench tower.

[0035] In Step 6, the flue gas generated in the combustion chamber is introduced into the secondary combustion chamber to ensure that the flue gas is maintained at a temperature exceeding 850 °C for a retention period of over 2 seconds, the flue gas produced by the secondary combustion chamber is split by the guide plate, and one portion of the flue gas is diverted to the diversion chamber and another portion of the flue gas is discharged through the secondary combustion chamber outlet flue duct.

[0036] In Step 7, after entering the diversion chamber, the high-temperature flue gas is introduced into positions at different heights of the drying pyrolysis chamber after passing through the plurality of flue gas nozzles in sequence.

[0037] As one further preferred solution, in Step 1, three sealing gates are arranged at the waste inlet of the drying pyrolysis chamber, during adding the waste, firstly, the first sealing gate is opened to receive the waste, then closed. Subsequently, the second sealing gate is opened, then closed. Finally, the third sealing gate is opened to allow the waste to enter the drying pyrolysis chamber.

[0038] As one further preferred solution, in Step 3, the dried waste is discharged from the waste outlet to the grate assembly, and the waste is fallen smoothly by rotating the switch plate to flip up and down.

[0039] As one further preferred solution, in Step 6, quantities of the flue gas between the diversion chamber and the secondary combustion chamber outlet flue duct are regulated by modulating an installation position of the guide plate, and an adjustment process is implemented as follows.

[0040] Element components of the waste entering the drying pyrolysis chamber are defined as C ar , H ar , O ar , N ar and S ar , and a moisture of the waste is defined as M ar .

[0041] A mass, a moisture content, a heat value and a temperature of the waste entering the drying pyrolysis chamber are defined as m 1 , w 1 , Q 1 and t 1 , respectively.

[0042] A mass, a moisture content, a heat value and a temperature of the waste discharging from the drying pyrolysis chamber are defined as m 2 , w 2 , Q 2 and t 2 , respectively.

[0043] A temperature of the flue gas entering the drying pyrolysis chamber from the flue gas nozzle is defined as t 3 and a temperature of the flue gas entering the drying pyrolysis chamber outlet flue duct from the drying pyrolysis chamber is defined as t 4 .

[0044] Specific heat capacities of the waste, water, water vapor, and high-temperature flue gas are defined as c 1 , c 2 , c 3 , and c 4 , respectively.

[0045] An excess air coefficient in the incinerator is defined as α.

[0046] A latent heat of a vaporization of water is defined as q.

[0047] Pressures at the secondary combustion chamber, the diversion chamber, and the secondary combustion chamber outlet flue are defined as P, P 1 , and P 2 , respectively.

[0048] A distance between the guide plate and a flue opening leading to the diversion chamber is defined as L 1 , and a distance between the guide plate and a flue opening leading to the secondary combustion chamber outlet flue is defined as L 2 .

[0049] A quantity of the flue gas entering the diversion chamber from the secondary combustion chamber is defined as V 1 , a quantity of the flue gas entering the secondary combustion chamber outlet flue from the secondary combustion chamber is defined as V 2 .

[0050] Then, a heat required by the drying pyrolysis chamber is H 1 = m 1 − m 2 q + c 1 m 1 1 − w 1 t 2 − t 1 + c 2 m 1 w 1 100 − t 1 + c 3 m 1 − m 2 t 4 − 100 .

[0051] A quantity of the high-temperature flue gas required to be introduced into the drying pyrolysis chamber is V 1 = m 1 − m 2 q + c 1 m 1 1 − w 1 t 2 − t 1 + c 2 m 1 w 1 100 − t 1 + c 3 m 1 − m 2 t 4 − 100 c 4 t 3 − t 4

[0052] A quantity of the flue gas produced by a combustion of the secondary combustion chamber is V y = m 1 1 × 10 − 6 + 0.0903 α C ar + 7 × 10 − 6 + 0.0338 α S ar + 0.05535 + 0.2693 α H ar + 0.006993 − 0.0338 α O ar + 0.008 N ar + 0.0124 M ar

[0053] A following equation is tenable through modulating a position of the guide plate and a power of the induced draft fan, V 1 V y = P − P 1 L 1 P − P 2 L 2

[0054] A control method for a small-scale domestic waste incinerator is obtained through substituting Formulas (1) and (2) into Formula (3), L 1 and L 2 are varied through modulating the position of the guide plate, and P 1 and P 2 are varied through modulating the power of the induced draft fan, finally Formula (3) is tenable, so that the quantity of the high-temperature flue gas entering the drying pyrolysis chamber satisfy the heat required for reducing the moisture content of the waste from w 1 to w 2 .Benefit effects

[0055] (1) Domestic waste typically has a moisture content exceeding 50% and a consequently low calorific value. The direct incineration of such high-moisture waste results in insufficient combustion temperatures and incomplete combustion, as evidenced by a high loss on ignition. To maintain the legally required furnace temperature of 850 °C for at least 2 seconds, a substantial amount of auxiliary fuel must be introduced, leading to significantly elevated operational costs.

[0056] A small-scale domestic waste incinerator is developed by the present invention, and the incinerator includes a drying pyrolysis chamber, a grate assembly, a combustion chamber, a secondary combustion chamber, a diversion chamber, an induced draft fan, and a condenser. The domestic waste is added to the drying pyrolysis chamber after being sorted and crushed, and the domestic waste is dried and pyrolyzed by the high-temperature flue gas introduced from the secondary combustion chamber. The water vapor and a small quantity of the combustible gas generated by the drying pyrolysis are introduced into the combustion chamber after being condensed. The dried waste is completely combusted in the combustion chamber through the grate assembly, and then enters the secondary combustion chamber to ensure 850 °C for at least 2 seconds.

[0057] In this method, the moisture content of the waste entering the incinerator is reduced, the heat value for the waste is increased, which can satisfy the requirement of 850 °C for at least 2 seconds in the incinerator without supplementing fuel, and the waste is combusted completely, and the ignition loss is low.

[0058] (2) In the existing small-scale domestic waste incinerators, the drying pyrolysis chamber is in direct connection with the combustion chamber. The temperature of the drying pyrolysis chamber is relatively high at the bottom, and the air supplemented to the combustion chamber also enters the drying pyrolysis chamber, so that the waste at the bottom of the drying pyrolysis chamber is prone to combustion, and the temperature is relatively high in the drying pyrolysis chamber, which causes a great damage to the equipment, and once the drying pyrolysis chamber is combusted, it is prone to produce the situations such as the material collapse and the airflow turbulence, and a large quantity of the high-temperature uncombusted flue gas is escaped from the top of the drying pyrolysis chamber, which results in a great safety risk.

[0059] In the present invention, the drying pyrolysis chamber is separated from the combustion chamber by a feeding grate assembly, which prevents the gas in the combustion chamber from entering the drying pyrolysis chamber, and can ensure an oxygen-deficient atmosphere in the drying pyrolysis chamber, so that the problems such as excessive temperature, material collapse, uncombusted flue gas escape, and poor material feeding caused by coking caused by the combustion will not occur.

[0060] (3) Some drying pyrolysis chambers merely utilizes the radiant heat from the furnace to dry the waste, which results in low drying efficiency. Although some utilizes the hot flue gas to dry the waste, the hot flue gas is unevenly distributed, and it is difficult to effectively control the quantity and the distribution of the hot flue gas, which results in the poor dryness degree and uniformity of the waste.

[0061] In this present invention, a diversion chamber is situated at the outlet of the secondary combustion chamber, the high-temperature flue gas generated by the secondary combustion chamber is introduced into the drying pyrolysis chamber after passing through the diversion chamber, and waste is dried through a direct contact between the high-temperature flue gas and the waste, which has a higher drying efficiency. The flue gas nozzles located on different layers with different size are opened on the wall surface connecting the diversion chamber and the drying pyrolysis chamber from top to bottom, the quantity of the flue gas entering different positions of the drying pyrolysis chamber 1 is controlled through varying the size of the flue gas nozzle, and the drying uniformity is better.

[0062] (4) The existing drying pyrolysis chamber has a complex structure, with many internal components and equipment, which is prone to be blocked, and is difficult in feeding materials, and the temperature is relative high in the drying pyrolysis chamber, the internal components and equipment are prone to be damaged, and the costs is also relative high.

[0063] In the present invention, the drying pyrolysis chamber has a simple structure, without many internal components and equipment, and only a material-dispensing device is installed at the bottom of the drying pyrolysis chamber. The waste in the drying pyrolysis chamber is loosened by rotating the material-dispensing device, and the waste is fed smoothly. The top of the drying pyrolysis chamber is sealed by a sealing gate to ensure the airtightness of the drying pyrolysis chamber. The device has a simple structure, low costs and low failure rate.

[0064] (5) The flue gas dried in the existing drying pyrolysis chamber is directly introduced into the combustion chamber or the secondary combustion chamber for combustion. A large quantity of the moisture generated by the waste drying enters the flue gas again, which results in a high moisture content in the flue gas and lowering the flue gas temperature.

[0065] In the present invention, the flue gas generated by the drying pyrolysis chamber is firstly condensed, then the moisture is removed, sequentially, the flue gas is introduced into the combustion chamber and the secondary combustion chamber. In this method, the moisture content in the flue gas is reduced, and the condensation and the bag sticking are avoided, and the temperature of the secondary combustion chamber is increased through reducing the quantity of the flue gas entering the secondary combustion chamber. The condensed water can be taken as a supplement to a quench tower at a rear end to reduce the water consumption.

[0066] (6) The drying process in the existing drying pyrolysis chamber is difficult to be controlled. The quantity of the flue gas entering the drying pyrolysis chamber cannot be effectively controlled, and the position and distribution of the flue gas entering the drying pyrolysis chamber cannot be adjusted. In the case of the fluctuations in moisture and components, the drying pyrolysis chamber and incinerator cannot be effectively, quantitatively, and accurately controlled.

[0067] In the present invention, a control method adapted to a small-scale domestic waste incinerator is developed. The quantity of the flue gas entering the drying pyrolysis chamber can be controlled through varying the position of the guide plate in the secondary combustion chamber and the fan power. When the moisture and the components of the waste are varied, the quantity of the flue gas entering the drying pyrolysis chamber can be regulated in a timely, effective and accurate manner by quantitatively varying the position of the guide plate and the fan power, thereby converting the complex and variable waste into the waste with stable heat value, so that the stable operations of the incinerator and the entire device are ensured.BRIEF DESCRIPTION OF THE DRAWINGS

[0068] FIG. 1 illustrates a schematic diagram of an overall structure of the present invention.

[0069] In the drawing, 1, Drying pyrolysis chamber; 2, Grate assembly; 3, Combustion chamber; 4, Secondary combustion chamber; 5, Secondary combustion chamber outlet flue duct; 6, Diversion chamber; 7, Induced draft fan; 8, Condenser; 9, Pyrolysis gas nozzle; 10, Sealing gate; 11, Switch plate; 12: Flue gas nozzle; 13, Guide plate; 14: Drying pyrolysis chamber outlet flue duct.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0070] The technical solutions of the embodiments in the present invention will be described clearly and completely below with reference to the accompanying drawings of the embodiments in the present invention. Obviously, the described embodiments are merely one part of the embodiments of the present invention, rather than all the embodiments.

[0071] A small-scale domestic waste incinerator is developed by the present invention, which mainly refers to the domestic waste incinerators with a scale of less than 50 tons per day. The incinerator includes a drying pyrolysis chamber 1, a grate assembly 2, a combustion chamber 3, a secondary combustion chamber 4, a diversion chamber 6, an induced draft fan 7 and a condenser 8. A drying pyrolysis chamber 1 is added in front of the combustion chamber 3, and the domestic waste is added to the drying pyrolysis chamber 1 after be sorted and crushed, then the high-temperature flue gas introduced from the secondary combustion chamber 4 is introduced into the drying pyrolysis chamber 1 through the diversion chamber 6 to dry and pyrolyze the domestic waste.

[0072] After the waste is dried, the moisture content is reduced, the heat value is increased, and the components are relatively stable, and the dried waste can be stably combusted in the combustion chamber 3. The requirement of 850 °C for at least 2 seconds is satisfied without supplementing fuel to the secondary combustion chamber 4, and the concentration of the flue gas pollutants is relative low, and a novel control method for the small-scale domestic waste incinerator is further developed, which can adapt to the waste with different moisture content, heat value and components through the design of the structures of the secondary combustion chamber 4 and the diversion chamber 6, as well as the adjustment of process parameters.

[0073] Specifically, the water vapor and a small quantity of the combustible gas generated by the drying pyrolysis are introduced into the combustion chamber 3 after condensing. The dried waste is completely combusted in the combustion chamber 3 through the grate assembly 2, and then enters the secondary combustion chamber 4 to ensure 850 °C for at least 2 seconds. One portion of the flue gas generated in the secondary combustion chamber 4 is introduced into the drying pyrolysis chamber 1 after passing through the diversion chamber 6, and the other portion of the flue gas generated in the secondary combustion chamber 4 is discharged from the secondary combustion chamber outlet flue 5.

[0074] In the present invention, the drying pyrolysis chamber 1 is separated from the combustion chamber 3 by the feeding grate assembly 2, and the drying pyrolysis chamber 1 and the combustion chamber 3 are not directly connected to each other, which prevents the gas in the combustion chamber 3 from entering the drying pyrolysis chamber 1, and can ensure an oxygen-deficient atmosphere in the drying pyrolysis chamber 1, so that the problems such as excessive temperature, material collapse, uncombusted flue gas effusion and poor material discharging due to coking caused by the combustion cannot be generated.

[0075] In the present invention, a diversion chamber 6 is arranged at the outlet of the secondary combustion chamber 4, and the high-temperature flue gas generated by the secondary combustion chamber 4 is introduced into the drying pyrolysis chamber 1 after passing through the diversion chamber 6. The waste is dried by a direct contact between the high-temperature flue gas and the waste, which has a higher drying efficiency and the hot flue gas can be quantitatively and controllably introduced into the drying pyrolysis chamber 1.

[0076] The flue gas nozzles 12 located on three layers with different sizes are opened on the wall surface connecting the diversion chamber 6 and the drying pyrolysis chamber 1 from top to bottom. The quantity of the flue gas entering different positions of the dry pyrolysis chamber 1 is controlled through varying the size of the flue gas nozzle 12, so that the hot flue gas can uniformly enter different positions of the waste material layer, and the uniformity of the entire drying pyrolysis chamber 1 is ensured.

[0077] In the present invention, the drying pyrolysis chamber 1 has a simple structure, and does not have many internal components and equipment, only a material-dispensing device is installed at the bottom of the drying pyrolysis chamber 1. The waste is loosen in the drying pyrolysis chamber 1 by rotating the material-dispensing device to ensure that the waste is discharged smoothly. A sealing gate 10 is installed at the top of the drying pyrolysis chamber 1 to ensure the airtightness of the dying pyrolysis chamber 1. The device has a simple structure, low costs, and low failure rate.

[0078] In the present invention, the flue gas generated by the drying pyrolysis chamber 1 is firstly condensed to remove the moisture, then introduced into the combustion chamber 3 and the secondary combustion chamber 4. In this method, the moisture content in the flue gas is reduced and the condensation and bag sticking are avoided, and the quantity of the flue gas introduced into the secondary combustion chamber 4 can be reduced and the temperature of the secondary combustion chamber 4 can be increased. The condensed water can be taken as a supplement to a quench tower at rear end to reduce the water consumption.

[0079] In the present invention, the quantity of the flue gas entering the dry pyrolysis chamber 1 can be controlled by varying the position of the guide plate 13 in the secondary combustion chamber 4 and the fan power. When the moisture and the components of the waste are varied, the quantity of the flue gas entering the drying pyrolysis chamber 1 can be regulated in a timely, effective and accurate manner by quantitatively varying the position of the guide plate 13 and the fan power, thereby converting the complex and variable waste into the waste with stable heat value, so that the stable operations of the incinerator and the entire device are ensured.

[0080] The specific processes of the incinerator are as follows. (1) The waste is added into the drying pyrolysis chamber 1 by a bucket elevator after being sorted and crushed. Since three sealing gates 10 are installed at the top of the drying pyrolysis chamber 1, during adding material, firstly, the first sealing gate 10 is opened to receive the waste, then closed. Subsequently, the second sealing gate 10 is opened, then closed. Finally, the third sealing gate 10 is opened to allow the waste to enter the drying pyrolysis chamber. The airtightness of the drying pyrolysis chamber 1 can be ensured by controlling the sealing gates 10. (2) The high-temperature flue gas produced by the combustion in the secondary combustion chamber 4 is introduced through the flue gas nozzles 12 located on three layers on the side wall of the drying pyrolysis chamber 1. A drying and a pyrolysis reaction are performed on the waste in the drying pyrolysis chamber 1 under a heating of the high-temperature to generate water vapor and a small quantity of combustible gas. The generated water vapor and the small quantity of combustible gas are introduced into the high-temperature flue gas and discharged from the drying pyrolysis chamber outlet flue duct 14. A switch plate 11 is arranged at the bottom of the drying pyrolysis chamber 1, which can be flipped up and down to enable the waste to fall smoothly. (3) The dried waste is fallen onto the grate assembly 2. The grate assembly 2 is formed by slidable grates and fixed grates. The waste is moved forward through the pushing of the slidable grate. When the waste is passed through the fixed grate and fallen off, a turning over of the waste is completed. The bottom slags produced by the combustion of the waste are discharged from the slag outlet, and the flue gas is introduced into the combustion chamber 3. (4) A primary air is supplied from beneath the gate assembly 2 into the combustion chamber 3, and s secondary air is introduced through the furnace rear arch. Under the action of the secondary air, the flue gas is completely mixed to ensure the complete combustion. The flue gas produced by the drying pyrolysis chamber 1 is condensed by the condenser 8 and the dry flue gas is recirculated to the combustion chamber 3 via the pyrolysis gas nozzle 9 to completely combust a small quantity of the combustible gas. The condensed water generated by the condenser 8 can be utilized as the makeup water for the quench tower. (5) The flue gas generated in the combustion chamber 3 enters the secondary combustion chamber 4, which ensures that the flue gas is maintained at a temperature exceeding 850 °C for a retention period of over 2 seconds. One portion of the flue gas generated in the secondary combustion chamber 4 is introduced into the diversion chamber 6 through the guide plate 13, and the other portion of the flue gas is discharged from the secondary combustion chamber outlet flue duct 5. (6) The diversion chamber 6 is separated from the secondary combustion chamber 4 by the refractory materials. After entering the diversion chamber 6, the high-temperature flue gas is passed through the flue gas nozzles 12 located on three layers in sequence and then introduced into different positions of the drying pyrolysis chamber 1.

[0081] Furthermore, the diameters of the flue gas nozzles located on three layers are increased step by step from top to bottom. The quantities of the flue gas of the high-temperature flue gas entering the different positions of the drying pyrolysis chamber 1 are basically the same through varying the diameters of the flue gas nozzles 12, so that the waste in the entire drying pyrolysis chamber 1 can be dried more evenly.

[0082] Furthermore, the position of the guide plate 13 is moveable, so as to adapt to the moisture content of different waste. The specific control method is as follows.

[0083] The element components of the waste at the entrance of the drying pyrolysis chamber 1 are defined as C ar , H ar , O ar , N ar and S ar , and the moisture of the waste is defined as M ar .

[0084] The mass, moisture content, heat value and temperature of the waste at the inlet of the drying pyrolysis chamber 1 are defined as m 1 , w 1 , Q 1 and t 1 , respectively.

[0085] The mass, moisture content, heat value and temperature of the waste at the outlet of drying pyrolysis chamber 1 are defined as m 2 , w 2 , Q 2 and t 2 , respectively.

[0086] The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are defined as t 3 and t 4 , respectively.

[0087] The specific heat capacities of the waste, water, water vapor, and high-temperature flue gas are defined as c 1 , c 2 , c 3 , and c 4 , respectively.

[0088] The excess air coefficient in the incinerator is defined as α.

[0089] The latent heat of the vaporization of water is defined as q.

[0090] The pressures at the secondary combustion chamber 4, the diversion chamber 6, and the secondary combustion chamber outlet flue 5 are defined as P, P 1 , and P 2 , respectively.

[0091] The distance between the guide plate 13 and the left side of the secondary combustion chamber 4 is defined as L 1 , and the distance between the guide plate 13 and the right side of the secondary combustion chamber 4 is defined as L 2 .

[0092] The quantity of the flue gas introduced from the secondary combustion chamber 4 to the diversion chamber 6 is defined as V 1 , and the quantity of the flue gas introduced from the secondary combustion chamber 4 to the secondary combustion chamber outlet flue 5 is defined as V 2 .

[0093] Then, the heat required by the drying pyrolysis chamber 1 for is H 1 = m 1 − m 2 q + c 1 m 1 1 − w 1 t 2 − t 1 + c 2 m 1 w 1 100 − t 1 + c 3 m 1 − m 2 t 4 − 100 .

[0094] The quantity of the high-temperature flue gas required to be introduced into the drying pyrolysis chamber 1 is V 1 = m 1 − m 2 q + c 1 m 1 1 − w 1 t 2 − t 1 + c 2 m 1 w 1 100 − t 1 + c 3 m 1 − m 2 t 4 − 100 c 4 t 3 − t 4

[0095] The quantity of the flue gas generated by the combustion of the secondary combustion chamber 4 is V y = m 1 1 × 10 − 6 + 0.0903 α C ar + 7 × 10 − 6 + 0.0338 α S ar + 0.05535 + 0.2693 α H ar + 0.006993 − 0.0338 α O ar + 0.008 N ar + 0.0124 M ar

[0096] The following equation is tenable through modulating the position of the guide plate 13 and the power of the induced draft fan (7), V 1 V y = P − P 1 L 1 P − P 2 L 2

[0097] The control method for a small-scale domestic waste incinerator can be obtained through substituting Formulas (1) and (2) into Formula (3), L 1 and L 2 are varied through modulating the position of the guide plate (13), and P 1 and P 2 are varied through modulating the power of the induced draft fan (7), finally Formula (3) is tenable, so that the quantity of the high-temperature flue gas entering the drying pyrolysis chamber satisfy the heat required for reducing the moisture content of the waste from w 1 to w 2 .

[0098] This control method can adapt to the situations of the variations in different waste components. When the moisture content of the waste is varied, the quantity of the high-temperature flue gas entering the drying pyrolysis chamber 1 is varied by modulating the position of the guide plate 13 and the power of the induced draft fan 7, and finally the moisture content and heat value for the waste entering the grate assembly 2 are kept constant.

[0099] In the device and the control method, the complex and variable waste can be converted into the waste with stable moisture content and the heat value, so that the stability of the combustion in the incinerator is ensured. And the moisture content of the waste is reduced and the heat value for the waste is increased through setting a drying pyrolysis chamber 1, so that the incineration temperature is increased and the requirement of 850 °C for at least 2 seconds can be satisfied without supplementing fuel. In this method, the distribution of the high-temperature flue gas generated by the secondary combustion chamber 4 can be quantitatively controlled, so that the heat value for the dried waste can be controlled more accurately, and the automatic control is implemented.Embodiment 1

[0100] The components of the original waste are as indicated in the following table: Component NameC ar H ar O ar N ar S ar M ar Numerical Value / %182100.70.560

[0101] The heat value for the original waste is 1343 kcal / kg.

[0102] It is required to increase the heat value for the waste entering the furnace to 2000 kcal / kg by drying in the pyrolysis chamber 1. The moisture content of the waste entering the furnace is 46.5%.

[0103] The treatment scale of the small-scale domestic waste is 500 kg / h, and the temperature of the original waste is 20 °C.

[0104] The temperature of the waste at the outlet of the drying pyrolysis chamber 1 is 300 °C and the mass flow rate is 374 kg / h.

[0105] The excess air coefficient of the incinerator is 1.4.

[0106] The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are 1050 °C and 200 °C, respectively.

[0107] The pressures in the secondary combustion chamber 4, the induced draft chamber 6 and the secondary combustion chamber outlet flue 5 are respectively -100 kPa, -300 kPa, and -250 kPa through the control of the induced draft fan 7.The position of the guide plate 13 is required to be modulated, so that L 1 / L 2 =0.214.

[0108] The position of the guide plate and the power of the induced draft fan 7 are modulated according to the above method, so that the heat value for the waste entering the furnace can be 2000 kcal / kg.Embodiment 2

[0109] When the components of the original waste are varied, and the components are as indicated in the following table: Component nameC ar H ar O ar N ar S ar M ar Numerical value / %202.5121.00.750

[0110] At this time, the heat value for the original waste is 1641 kcal / kg.

[0111] The waste is still required to be dried through the drying pyrolysis chamber 1 to increase the heat value for the waste entering the furnace to 2000 kcal / kg, and the moisture content of the waster entering the furnace is 42.0 %.

[0112] The treatment scale of small-scale domestic waste treatment is still 500 kg / h, and the temperature of the original waste is 20 °C.

[0113] The temperature of the waste at the outlet of the drying pyrolysis chamber 1 is 300 °C and the mass flow rate is 431 kg / h.

[0114] The excess air coefficient of the incinerator is 1.4.

[0115] The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are 1050 °C and 200 °C, respectively.

[0116] The pressures in the secondary combustion chamber 4, the induced draft chamber 6 and the secondary combustion chamber outlet flue 5 are respectively -100 kPa, -300 kPa, and -250 kPa through the control of the induced draft fan 7.

[0117] The position of the guide plate 13 is required to be modulated, so that L 1 / L 2 =0.154.

[0118] The position of the guide plate 13 and the power of the induced draft fan 7 are modulated according to the above method, so that the heat value for the waste entering the furnace can be 2000 kcal / kg.

[0119] In comparison with Embodiment 1, when the moisture content of the original waste is reduced and the heat value for the original waste is increased, and the pressures in the secondary combustion chamber 4, the draft chamber 6 and the secondary combustion chamber outlet flue 5 are kept unvaried after modulating the induced draft fan 7, then the guide plate 13 is required to be moved towards the diversion chamber 6 to reduce the quantity of the flue gas entering the drying pyrolysis chamber 1.Embodiment 3

[0120] When the components of the original waste are varied, and the components are as indicated in the following table: Component nameC ar H ar O ar N ar S ar M ar Numerical value / %222.7131.20.840

[0121] At this time, the heat value for the original waste is 1889 kcal / kg.

[0122] The waste is still required to be dried through the drying pyrolysis chamber 1 to increase the heat value for the waste entering the furnace to 2000 kcal / kg, and the moisture content of the waster entering the furnace is 37.3 %.

[0123] The treatment scale of small-scale domestic waste is still 500 kg / h, and the temperature of the original waste is 20 °C.

[0124] The temperature of the waste at the outlet of the drying pyrolysis chamber 1 is 300 °C and the mass flow rate is 478 kg / h.

[0125] The excess air coefficient of the incinerator is 1.4.

[0126] The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are 1050 °C and 200 °C, respectively.

[0127] The pressures in the secondary combustion chamber 4, the induced draft chamber 6, and the secondary combustion chamber outlet flue 5 are respectively -100 kPa, -300 kPa, and -250 kPa through the control of the induced draft fan 7.

[0128] The position of the guide plate 13 is required to be modulated, so that L 1 / L 2 =0.110.

[0129] The position of the guide plate 13 and the power of the induced draft fan 7 are modulated according to the above method, so that the heat value for the waste entering the furnace can be reached 2000 kcal / kg.

[0130] In comparison with Embodiment 2, when the moisture content of the original garbage is further reduced and the heat value is increased, and the pressures in the secondary combustion chamber 4, the diversion chamber 6, and the secondary combustion chamber outlet flue 5 are kept unvaried after modulating the induced draft fan 7, the guide plate 13 is further required to be moved towards the diversion chamber 6 to reduce the quantity of the flue gas entering the drying pyrolysis chamber 1.

[0131] The above descriptions are merely the preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. A technician familiar with the technical field can make equivalent replacements or variations according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Examples

embodiment 1

[0100]The components of the original waste are as indicated in the following table:

Component NameC ar H ar O ar N ar S ar M ar

Numerical Value / %182100.70.560

[0101]The heat value for the original waste is 1343 kcal / kg.

[0102]It is required to increase the heat value for the waste entering the furnace to 2000 kcal / kg by drying in the pyrolysis chamber 1. The moisture content of the waste entering the furnace is 46.5%.

[0103]The treatment scale of the small-scale domestic waste is 500 kg / h, and the temperature of the original waste is 20 °C.

[0104]The temperature of the waste at the outlet of the drying pyrolysis chamber 1 is 300 °C and the mass flow rate is 374 kg / h.

[0105]The excess air coefficient of the incinerator is 1.4.

[0106]The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are 1050 °C and 200 °C, respectively.

[0107]The pressures in the secondary combustion chamber 4, the induced draft chamber 6 and the secondary c...

embodiment 2

[0109]When the components of the original waste are varied, and the components are as indicated in the following table:

Component nameC ar H ar O ar N ar S ar M ar

Numerical value / %202.5121.00.750

[0110]At this time, the heat value for the original waste is 1641 kcal / kg.

[0111]The waste is still required to be dried through the drying pyrolysis chamber 1 to increase the heat value for the waste entering the furnace to 2000 kcal / kg, and the moisture content of the waster entering the furnace is 42.0 %.

[0112]The treatment scale of small-scale domestic waste treatment is still 500 kg / h, and the temperature of the original waste is 20 °C.

[0113]The temperature of the waste at the outlet of the drying pyrolysis chamber 1 is 300 °C and the mass flow rate is 431 kg / h.

[0114]The excess air coefficient of the incinerator is 1.4.

[0115]The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are 1050 °C and 200 °C, respectively.

[0116]Th...

embodiment 3

[0120]When the components of the original waste are varied, and the components are as indicated in the following table:

Component nameC ar H ar O ar N ar S ar M ar

Numerical value / %222.7131.20.840

[0121]At this time, the heat value for the original waste is 1889 kcal / kg.

[0122]The waste is still required to be dried through the drying pyrolysis chamber 1 to increase the heat value for the waste entering the furnace to 2000 kcal / kg, and the moisture content of the waster entering the furnace is 37.3 %.

[0123]The treatment scale of small-scale domestic waste is still 500 kg / h, and the temperature of the original waste is 20 °C.

[0124]The temperature of the waste at the outlet of the drying pyrolysis chamber 1 is 300 °C and the mass flow rate is 478 kg / h.

[0125]The excess air coefficient of the incinerator is 1.4.

[0126]The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are 1050 °C and 200 °C, respectively.

[0127]The pressure...

TECHNICAL FIELD

[0001] The present invention relates to the technical field of waste incinerators, and in particular to a small-scale domestic waste incinerator and a using method thereof.BACKGROUND

[0002] Currently, waste incineration technology is relatively mature, primarily applied in large-scale facilities designed for centralized urban waste treatment. However, in remote and island areas with scattered populations and low waste generation, transportation costs are prohibitively high, making centralized incineration impractical. As a result, decentralized, small-scale, on-site waste disposal solutions suitable for rural, township, and island settings represent a key direction for future development. This growing need has driven strong demand for small-scale domestic waste incinerators.

[0003] The main problems of the technology of the incinerator for the small-scale domestic waste incinerator are as follows. (1) The domestic waste has a high moisture content and low heat value, which results in incomplete combustion and requires a large quantity of additional fuel.

[0004] Domestic waste typically has a moisture content exceeding 50% and a consequently low calorific value. The direct incineration of such high-moisture waste results in insufficient combustion temperatures and incomplete combustion, as evidenced by a high loss on ignition. To maintain the legally required furnace temperature of 850 °C for at least 2 seconds, a substantial amount of auxiliary fuel must be introduced, leading to significantly elevated operational costs.

[0005] (2) The amount of domestic waste to be treated is small, and its composition is highly variable, leading to operational difficulties.

[0006] The small treatment scale and highly variable composition of the waste pose significant challenges to the incinerator and auxiliary systems, hindering stable operation and adjustment.

[0007] (3) The high concentration of pollutants in the flue gas makes compliance with emission standards challenging.

[0008] Due to low combustion temperatures and high initial pollutant concentrations, many small-scale waste incineration systems lack online flue gas monitoring. Furthermore, ensuring emissions compliance under these conditions results in prohibitively high operating costs.

[0009] (4) The low volume of flue gas presents a significant challenge for the effective and economical utilization of its waste heat.

[0010] Small-scale waste incineration systems produce a limited volume of flue gas, which often makes waste heat recovery impractical. Consequently, rapid quenching is typically employed for gas conditioning. This method, however, is highly inefficient. It not only wastes substantial thermal energy but also introduces excessive moisture into the flue gas. The resulting severe condensation readily leads to bag clogging in the filtration system.

[0011] (5) Conventional incinerators are typically bulky, structurally complex, and space-consuming, resulting in high operational and maintenance costs.

[0012] Existing small-scale waste incinerators still adopt the structural design of large-scale systems, comprising drying, combustion, and ash sections with a complex grate assembly. This results in equipment that is overly large, space-consuming, structurally complicated, and costly.

[0013] Patent CN118189179B discloses a pyrolysis gasification small-scale domestic waste incinerator and process. It positions a pyrolysis chamber at the incinerator's front end and introduces hot flue gas into it to dry and pyrolyze the waste, thereby reducing moisture and increasing calorific value. Nevertheless, this method faces several challenges: precise control over the volume and uniform distribution of the incoming hot flue gas is difficult, leading to inconsistent waste drying. Moisture released during drying remains in the flue gas, raising its humidity and promoting condensation and bag clogging. Furthermore, the direct connection between the pyrolysis and combustion chambers causes excessive bottom temperatures and allows excess air, making the waste prone to open combustion and complicating reaction and temperature control.

[0014] Patent CN108980847B discloses a waste treatment process utilizing a drying layer and a carbonization layer at the incinerator's front end, using hot flue gas and furnace radiation for pre-treatment. While this method reduces waste moisture and increases calorific value, it suffers from several drawbacks. Structurally, the drying and carbonization grates are complex, with the latter operating at high temperatures that make it prone to damage. Operationally, the direct connection to the combustion chamber leads to excessive temperatures and air ingress in the carbonization layer, causing unwanted combustion and making process control difficult. Thermally, the limited rise and uncontrolled flow of hot flue gas result in low drying efficiency, as the drying layer relies primarily on radiant heat.

[0015] Patent CN220852160U discloses a garbage incinerator with a pyrolysis chamber positioned above the combustion chamber, relying solely on radiant heat for drying and pyrolysis. This design exhibits significant limitations: its sole reliance on radiant heat results in low drying efficiency and an inability to effectively control the drying rate. Furthermore, the process lacks the adjustability to handle variations in waste moisture, calorific value, and composition. Structurally, the horizontal arrangement of the pyrolysis chamber impedes waste flow, and the use of spiral feeding equipment in this configuration is prone to blockages.

[0016] In summary, most existing small-scale domestic waste incinerators inherit the structural design and processes of large-scale systems, leading to issues such as incomplete combustion, operational instability, non-compliant flue gas emissions, unutilized waste heat, and high costs. While a minority of designs incorporate a pre-combustion drying / pyrolysis chamber to reduce moisture and enhance calorific value, thereby improving combustion stability, and these chambers are often structurally complex, operationally challenging, and inefficient. Their direct connection to the combustion chamber also risks unwanted combustion and overheating within the chamber itself. Consequently, there is a clear need for a novel small-scale incinerator, particularly one equipped with an adaptive control strategy, to effectively handle waste characterized by low throughput, high moisture, low calorific value, and highly variable composition.SUMMARY

[0017] The technical objectives of the present invention are to solve the problems of the small-scale domestic waste incinerator, such as an incomplete waste combustion, a low combustion temperature, high auxiliary fuel demand, and non-compliant pollutant emissions, due to a high water content, a low heat value, and a large fluctuation of components. Therefore, it is necessary to develop a small-scale waste incinerator suitable for treating the waste with a high moisture content, a low heat value, and a large fluctuation of components, and a control method thereof.

[0018] In order to achieve the above objectives, the following technical solutions are adopted in the present invention.

[0019] Provided is a small-scale domestic waste incinerator. The incinerator comprises a drying pyrolysis chamber and a combustion chamber arranged over a grate assembly of the waste incinerator, the drying pyrolysis chamber is disposed at an upstream section of the grate assembly, and the combustion chamber is disposed at a downstream section of the grate group.

[0020] The drying pyrolysis chamber is vertically oriented, an upper end of the drying pyrolysis chamber is a waste inlet, and a lower end of the drying pyrolysis chamber is a waste outlet, and one part of the grate assembly is covered by the waste outlet of the drying pyrolysis chamber.

[0021] The grate assembly is enclosed by the combustion chamber, and a secondary combustion chamber is in communication with an upper portion of the combustion chamber, and a pyrolysis gas nozzle is mounted on a side wall of the combustion chamber in proximity to an upper section of the drying pyrolysis chamber.

[0022] A drying pyrolysis chamber outlet flue duct with an induced draft fan is provided on a side wall of the drying pyrolysis chamber in proximity to an upper end of the drying pyrolysis chamber, and the drying pyrolysis chamber outlet flue duct is in connection with the pyrolysis gas nozzle through a condenser.

[0023] A diversion chamber is situated between a same side of the combustion chamber and the secondary combustion chamber and one side of the drying pyrolysis chamber, a position of the diversion chamber is lower than a position of a circulating flue duct of the secondary combustion chamber, the diversion chamber is sealed at a bottom end, and a top end of the diversion chamber is a flue gas inlet, a side part of the drying pyrolysis chamber is provided with a plurality of flue gas nozzles along a longitudinal direction, and the flue gas nozzles are in communication with the diversion chamber.

[0024] A secondary combustion chamber outlet flue duct and a circulating flue duct are respectively arranged on both sides of a top part of the secondary combustion chamber, the circulating flue duct is in communication with the flue gas inlet of the diversion chamber, and a guide plate configured to regulate quantities of flue gas introduced into the secondary combustion chamber outlet flue duct and the circulating flue duct is installed on the top part of the secondary combustion chamber.

[0025] As one further preferred solution, calibers of the plurality of flue gas nozzles are sequentially increased from top to bottom.

[0026] As one further preferred solution, three sealing gates are arranged at the waste inlet of the drying pyrolysis chamber, and a switch plate is arranged at the waste outlet.

[0027] As one further preferred solution, the grate assembly is formed by slidable grates and fixed grates, and the slidable grates and the fixed grates are arranged in an alternating sequence.

[0028] As one further preferred solution, the waste outlet of the drying pyrolysis chamber is sealed by a first-stage slidable grate of the grate assembly, and the slidable grate is further taken as a feeding grate.

[0029] Further provided is a method for using a small-scale domestic waste incinerator, the method includes following steps.

[0030] In Step 1, the waste is added to the drying pyrolysis chamber by a bucket elevator after being sorted and crushed.

[0031] In Step 2, high-temperature flue gas produced by a combustion in the secondary combustion chamber is introduced through the plurality of flue gas nozzles on the side wall of the drying pyrolysis chamber, a drying and a pyrolysis reaction are performed on the waste in the drying pyrolysis chamber under a heating of the high-temperature to generate water vapor and a small quantity of combustible gas, and the generated water vapor and the small quantity of combustible gas are introduced into the high-temperature flue gas and discharged from the drying pyrolysis chamber outlet flue duct.

[0032] In Step 3, dried waste is fallen from the waste outlet onto the grate assembly, the waste are transported downstream with a pushing of the slidable grate in the grate assembly, and a turning-over is completed when the waste is passed through the fixed grate in the grate assembly and fallen off, bottom slags produced by a combustion of the waste is discharged from a slag outlet of the grate assembly, and the flue gas produced by the combustion is introduced into the combustion chamber.

[0033] In Step 4, a primary air is supplied from beneath the gate assembly into the combustion chamber, and a secondary air is introduced to the combustion chamber through an opening of a furnace rear arch, and under an action of the secondary air, the flue gas is completely mixed to ensure a complete combustion.

[0034] In Step 5, the flue gas produced by the pyrolysis chamber is condensed by the condenser, and the dry flue gas is recirculated into the combustion chamber via the pyrolysis gas nozzle to completely combust a small quantity of combustible gas, and condensed water produced by the condenser can be utilized as makeup water for a quench tower.

[0035] In Step 6, the flue gas generated in the combustion chamber is introduced into the secondary combustion chamber to ensure that the flue gas is maintained at a temperature exceeding 850 °C for a retention period of over 2 seconds, the flue gas produced by the secondary combustion chamber is split by the guide plate, and one portion of the flue gas is diverted to the diversion chamber and another portion of the flue gas is discharged through the secondary combustion chamber outlet flue duct.

[0036] In Step 7, after entering the diversion chamber, the high-temperature flue gas is introduced into positions at different heights of the drying pyrolysis chamber after passing through the plurality of flue gas nozzles in sequence.

[0037] As one further preferred solution, in Step 1, three sealing gates are arranged at the waste inlet of the drying pyrolysis chamber, during adding the waste, firstly, the first sealing gate is opened to receive the waste, then closed. Subsequently, the second sealing gate is opened, then closed. Finally, the third sealing gate is opened to allow the waste to enter the drying pyrolysis chamber.

[0038] As one further preferred solution, in Step 3, the dried waste is discharged from the waste outlet to the grate assembly, and the waste is fallen smoothly by rotating the switch plate to flip up and down.

[0039] As one further preferred solution, in Step 6, quantities of the flue gas between the diversion chamber and the secondary combustion chamber outlet flue duct are regulated by modulating an installation position of the guide plate, and an adjustment process is implemented as follows.

[0040] Element components of the waste entering the drying pyrolysis chamber are defined as C ar , H ar , O ar , N ar and S ar , and a moisture of the waste is defined as M ar .

[0041] A mass, a moisture content, a heat value and a temperature of the waste entering the drying pyrolysis chamber are defined as m 1 , w 1 , Q 1 and t 1 , respectively.

[0042] A mass, a moisture content, a heat value and a temperature of the waste discharging from the drying pyrolysis chamber are defined as m 2 , w 2 , Q 2 and t 2 , respectively.

[0043] A temperature of the flue gas entering the drying pyrolysis chamber from the flue gas nozzle is defined as t 3 and a temperature of the flue gas entering the drying pyrolysis chamber outlet flue duct from the drying pyrolysis chamber is defined as t 4 .

[0044] Specific heat capacities of the waste, water, water vapor, and high-temperature flue gas are defined as c 1 , c 2 , c 3 , and c 4 , respectively.

[0045] An excess air coefficient in the incinerator is defined as α.

[0046] A latent heat of a vaporization of water is defined as q.

[0047] Pressures at the secondary combustion chamber, the diversion chamber, and the secondary combustion chamber outlet flue are defined as P, P 1 , and P 2 , respectively.

[0048] A distance between the guide plate and a flue opening leading to the diversion chamber is defined as L 1 , and a distance between the guide plate and a flue opening leading to the secondary combustion chamber outlet flue is defined as L 2 .

[0049] A quantity of the flue gas entering the diversion chamber from the secondary combustion chamber is defined as V 1 , a quantity of the flue gas entering the secondary combustion chamber outlet flue from the secondary combustion chamber is defined as V 2 .

[0050] Then, a heat required by the drying pyrolysis chamber is H 1 = m 1 − m 2 q + c 1 m 1 1 − w 1 t 2 − t 1 + c 2 m 1 w 1 100 − t 1 + c 3 m 1 − m 2 t 4 − 100 .

[0051] A quantity of the high-temperature flue gas required to be introduced into the drying pyrolysis chamber is V 1 = m 1 − m 2 q + c 1 m 1 1 − w 1 t 2 − t 1 + c 2 m 1 w 1 100 − t 1 + c 3 m 1 − m 2 t 4 − 100 c 4 t 3 − t 4

[0052] A quantity of the flue gas produced by a combustion of the secondary combustion chamber is V y = m 1 1 × 10 − 6 + 0.0903 α C ar + 7 × 10 − 6 + 0.0338 α S ar + 0.05535 + 0.2693 α H ar + 0.006993 − 0.0338 α O ar + 0.008 N ar + 0.0124 M ar

[0053] A following equation is tenable through modulating a position of the guide plate and a power of the induced draft fan, V 1 V y = P − P 1 L 1 P − P 2 L 2

[0054] A control method for a small-scale domestic waste incinerator is obtained through substituting Formulas (1) and (2) into Formula (3), L 1 and L 2 are varied through modulating the position of the guide plate, and P 1 and P 2 are varied through modulating the power of the induced draft fan, finally Formula (3) is tenable, so that the quantity of the high-temperature flue gas entering the drying pyrolysis chamber satisfy the heat required for reducing the moisture content of the waste from w 1 to w 2 .Benefit effects

[0055] (1) Domestic waste typically has a moisture content exceeding 50% and a consequently low calorific value. The direct incineration of such high-moisture waste results in insufficient combustion temperatures and incomplete combustion, as evidenced by a high loss on ignition. To maintain the legally required furnace temperature of 850 °C for at least 2 seconds, a substantial amount of auxiliary fuel must be introduced, leading to significantly elevated operational costs.

[0056] A small-scale domestic waste incinerator is developed by the present invention, and the incinerator includes a drying pyrolysis chamber, a grate assembly, a combustion chamber, a secondary combustion chamber, a diversion chamber, an induced draft fan, and a condenser. The domestic waste is added to the drying pyrolysis chamber after being sorted and crushed, and the domestic waste is dried and pyrolyzed by the high-temperature flue gas introduced from the secondary combustion chamber. The water vapor and a small quantity of the combustible gas generated by the drying pyrolysis are introduced into the combustion chamber after being condensed. The dried waste is completely combusted in the combustion chamber through the grate assembly, and then enters the secondary combustion chamber to ensure 850 °C for at least 2 seconds.

[0057] In this method, the moisture content of the waste entering the incinerator is reduced, the heat value for the waste is increased, which can satisfy the requirement of 850 °C for at least 2 seconds in the incinerator without supplementing fuel, and the waste is combusted completely, and the ignition loss is low.

[0058] (2) In the existing small-scale domestic waste incinerators, the drying pyrolysis chamber is in direct connection with the combustion chamber. The temperature of the drying pyrolysis chamber is relatively high at the bottom, and the air supplemented to the combustion chamber also enters the drying pyrolysis chamber, so that the waste at the bottom of the drying pyrolysis chamber is prone to combustion, and the temperature is relatively high in the drying pyrolysis chamber, which causes a great damage to the equipment, and once the drying pyrolysis chamber is combusted, it is prone to produce the situations such as the material collapse and the airflow turbulence, and a large quantity of the high-temperature uncombusted flue gas is escaped from the top of the drying pyrolysis chamber, which results in a great safety risk.

[0059] In the present invention, the drying pyrolysis chamber is separated from the combustion chamber by a feeding grate assembly, which prevents the gas in the combustion chamber from entering the drying pyrolysis chamber, and can ensure an oxygen-deficient atmosphere in the drying pyrolysis chamber, so that the problems such as excessive temperature, material collapse, uncombusted flue gas escape, and poor material feeding caused by coking caused by the combustion will not occur.

[0060] (3) Some drying pyrolysis chambers merely utilizes the radiant heat from the furnace to dry the waste, which results in low drying efficiency. Although some utilizes the hot flue gas to dry the waste, the hot flue gas is unevenly distributed, and it is difficult to effectively control the quantity and the distribution of the hot flue gas, which results in the poor dryness degree and uniformity of the waste.

[0061] In this present invention, a diversion chamber is situated at the outlet of the secondary combustion chamber, the high-temperature flue gas generated by the secondary combustion chamber is introduced into the drying pyrolysis chamber after passing through the diversion chamber, and waste is dried through a direct contact between the high-temperature flue gas and the waste, which has a higher drying efficiency. The flue gas nozzles located on different layers with different size are opened on the wall surface connecting the diversion chamber and the drying pyrolysis chamber from top to bottom, the quantity of the flue gas entering different positions of the drying pyrolysis chamber 1 is controlled through varying the size of the flue gas nozzle, and the drying uniformity is better.

[0062] (4) The existing drying pyrolysis chamber has a complex structure, with many internal components and equipment, which is prone to be blocked, and is difficult in feeding materials, and the temperature is relative high in the drying pyrolysis chamber, the internal components and equipment are prone to be damaged, and the costs is also relative high.

[0063] In the present invention, the drying pyrolysis chamber has a simple structure, without many internal components and equipment, and only a material-dispensing device is installed at the bottom of the drying pyrolysis chamber. The waste in the drying pyrolysis chamber is loosened by rotating the material-dispensing device, and the waste is fed smoothly. The top of the drying pyrolysis chamber is sealed by a sealing gate to ensure the airtightness of the drying pyrolysis chamber. The device has a simple structure, low costs and low failure rate.

[0064] (5) The flue gas dried in the existing drying pyrolysis chamber is directly introduced into the combustion chamber or the secondary combustion chamber for combustion. A large quantity of the moisture generated by the waste drying enters the flue gas again, which results in a high moisture content in the flue gas and lowering the flue gas temperature.

[0065] In the present invention, the flue gas generated by the drying pyrolysis chamber is firstly condensed, then the moisture is removed, sequentially, the flue gas is introduced into the combustion chamber and the secondary combustion chamber. In this method, the moisture content in the flue gas is reduced, and the condensation and the bag sticking are avoided, and the temperature of the secondary combustion chamber is increased through reducing the quantity of the flue gas entering the secondary combustion chamber. The condensed water can be taken as a supplement to a quench tower at a rear end to reduce the water consumption.

[0066] (6) The drying process in the existing drying pyrolysis chamber is difficult to be controlled. The quantity of the flue gas entering the drying pyrolysis chamber cannot be effectively controlled, and the position and distribution of the flue gas entering the drying pyrolysis chamber cannot be adjusted. In the case of the fluctuations in moisture and components, the drying pyrolysis chamber and incinerator cannot be effectively, quantitatively, and accurately controlled.

[0067] In the present invention, a control method adapted to a small-scale domestic waste incinerator is developed. The quantity of the flue gas entering the drying pyrolysis chamber can be controlled through varying the position of the guide plate in the secondary combustion chamber and the fan power. When the moisture and the components of the waste are varied, the quantity of the flue gas entering the drying pyrolysis chamber can be regulated in a timely, effective and accurate manner by quantitatively varying the position of the guide plate and the fan power, thereby converting the complex and variable waste into the waste with stable heat value, so that the stable operations of the incinerator and the entire device are ensured.BRIEF DESCRIPTION OF THE DRAWINGS

[0068] FIG. 1 illustrates a schematic diagram of an overall structure of the present invention.

[0069] In the drawing, 1, Drying pyrolysis chamber; 2, Grate assembly; 3, Combustion chamber; 4, Secondary combustion chamber; 5, Secondary combustion chamber outlet flue duct; 6, Diversion chamber; 7, Induced draft fan; 8, Condenser; 9, Pyrolysis gas nozzle; 10, Sealing gate; 11, Switch plate; 12: Flue gas nozzle; 13, Guide plate; 14: Drying pyrolysis chamber outlet flue duct.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0070] The technical solutions of the embodiments in the present invention will be described clearly and completely below with reference to the accompanying drawings of the embodiments in the present invention. Obviously, the described embodiments are merely one part of the embodiments of the present invention, rather than all the embodiments.

[0071] A small-scale domestic waste incinerator is developed by the present invention, which mainly refers to the domestic waste incinerators with a scale of less than 50 tons per day. The incinerator includes a drying pyrolysis chamber 1, a grate assembly 2, a combustion chamber 3, a secondary combustion chamber 4, a diversion chamber 6, an induced draft fan 7 and a condenser 8. A drying pyrolysis chamber 1 is added in front of the combustion chamber 3, and the domestic waste is added to the drying pyrolysis chamber 1 after be sorted and crushed, then the high-temperature flue gas introduced from the secondary combustion chamber 4 is introduced into the drying pyrolysis chamber 1 through the diversion chamber 6 to dry and pyrolyze the domestic waste.

[0072] After the waste is dried, the moisture content is reduced, the heat value is increased, and the components are relatively stable, and the dried waste can be stably combusted in the combustion chamber 3. The requirement of 850 °C for at least 2 seconds is satisfied without supplementing fuel to the secondary combustion chamber 4, and the concentration of the flue gas pollutants is relative low, and a novel control method for the small-scale domestic waste incinerator is further developed, which can adapt to the waste with different moisture content, heat value and components through the design of the structures of the secondary combustion chamber 4 and the diversion chamber 6, as well as the adjustment of process parameters.

[0073] Specifically, the water vapor and a small quantity of the combustible gas generated by the drying pyrolysis are introduced into the combustion chamber 3 after condensing. The dried waste is completely combusted in the combustion chamber 3 through the grate assembly 2, and then enters the secondary combustion chamber 4 to ensure 850 °C for at least 2 seconds. One portion of the flue gas generated in the secondary combustion chamber 4 is introduced into the drying pyrolysis chamber 1 after passing through the diversion chamber 6, and the other portion of the flue gas generated in the secondary combustion chamber 4 is discharged from the secondary combustion chamber outlet flue 5.

[0074] In the present invention, the drying pyrolysis chamber 1 is separated from the combustion chamber 3 by the feeding grate assembly 2, and the drying pyrolysis chamber 1 and the combustion chamber 3 are not directly connected to each other, which prevents the gas in the combustion chamber 3 from entering the drying pyrolysis chamber 1, and can ensure an oxygen-deficient atmosphere in the drying pyrolysis chamber 1, so that the problems such as excessive temperature, material collapse, uncombusted flue gas effusion and poor material discharging due to coking caused by the combustion cannot be generated.

[0075] In the present invention, a diversion chamber 6 is arranged at the outlet of the secondary combustion chamber 4, and the high-temperature flue gas generated by the secondary combustion chamber 4 is introduced into the drying pyrolysis chamber 1 after passing through the diversion chamber 6. The waste is dried by a direct contact between the high-temperature flue gas and the waste, which has a higher drying efficiency and the hot flue gas can be quantitatively and controllably introduced into the drying pyrolysis chamber 1.

[0076] The flue gas nozzles 12 located on three layers with different sizes are opened on the wall surface connecting the diversion chamber 6 and the drying pyrolysis chamber 1 from top to bottom. The quantity of the flue gas entering different positions of the dry pyrolysis chamber 1 is controlled through varying the size of the flue gas nozzle 12, so that the hot flue gas can uniformly enter different positions of the waste material layer, and the uniformity of the entire drying pyrolysis chamber 1 is ensured.

[0077] In the present invention, the drying pyrolysis chamber 1 has a simple structure, and does not have many internal components and equipment, only a material-dispensing device is installed at the bottom of the drying pyrolysis chamber 1. The waste is loosen in the drying pyrolysis chamber 1 by rotating the material-dispensing device to ensure that the waste is discharged smoothly. A sealing gate 10 is installed at the top of the drying pyrolysis chamber 1 to ensure the airtightness of the dying pyrolysis chamber 1. The device has a simple structure, low costs, and low failure rate.

[0078] In the present invention, the flue gas generated by the drying pyrolysis chamber 1 is firstly condensed to remove the moisture, then introduced into the combustion chamber 3 and the secondary combustion chamber 4. In this method, the moisture content in the flue gas is reduced and the condensation and bag sticking are avoided, and the quantity of the flue gas introduced into the secondary combustion chamber 4 can be reduced and the temperature of the secondary combustion chamber 4 can be increased. The condensed water can be taken as a supplement to a quench tower at rear end to reduce the water consumption.

[0079] In the present invention, the quantity of the flue gas entering the dry pyrolysis chamber 1 can be controlled by varying the position of the guide plate 13 in the secondary combustion chamber 4 and the fan power. When the moisture and the components of the waste are varied, the quantity of the flue gas entering the drying pyrolysis chamber 1 can be regulated in a timely, effective and accurate manner by quantitatively varying the position of the guide plate 13 and the fan power, thereby converting the complex and variable waste into the waste with stable heat value, so that the stable operations of the incinerator and the entire device are ensured.

[0080] The specific processes of the incinerator are as follows. (1) The waste is added into the drying pyrolysis chamber 1 by a bucket elevator after being sorted and crushed. Since three sealing gates 10 are installed at the top of the drying pyrolysis chamber 1, during adding material, firstly, the first sealing gate 10 is opened to receive the waste, then closed. Subsequently, the second sealing gate 10 is opened, then closed. Finally, the third sealing gate 10 is opened to allow the waste to enter the drying pyrolysis chamber. The airtightness of the drying pyrolysis chamber 1 can be ensured by controlling the sealing gates 10. (2) The high-temperature flue gas produced by the combustion in the secondary combustion chamber 4 is introduced through the flue gas nozzles 12 located on three layers on the side wall of the drying pyrolysis chamber 1. A drying and a pyrolysis reaction are performed on the waste in the drying pyrolysis chamber 1 under a heating of the high-temperature to generate water vapor and a small quantity of combustible gas. The generated water vapor and the small quantity of combustible gas are introduced into the high-temperature flue gas and discharged from the drying pyrolysis chamber outlet flue duct 14. A switch plate 11 is arranged at the bottom of the drying pyrolysis chamber 1, which can be flipped up and down to enable the waste to fall smoothly. (3) The dried waste is fallen onto the grate assembly 2. The grate assembly 2 is formed by slidable grates and fixed grates. The waste is moved forward through the pushing of the slidable grate. When the waste is passed through the fixed grate and fallen off, a turning over of the waste is completed. The bottom slags produced by the combustion of the waste are discharged from the slag outlet, and the flue gas is introduced into the combustion chamber 3. (4) A primary air is supplied from beneath the gate assembly 2 into the combustion chamber 3, and s secondary air is introduced through the furnace rear arch. Under the action of the secondary air, the flue gas is completely mixed to ensure the complete combustion. The flue gas produced by the drying pyrolysis chamber 1 is condensed by the condenser 8 and the dry flue gas is recirculated to the combustion chamber 3 via the pyrolysis gas nozzle 9 to completely combust a small quantity of the combustible gas. The condensed water generated by the condenser 8 can be utilized as the makeup water for the quench tower. (5) The flue gas generated in the combustion chamber 3 enters the secondary combustion chamber 4, which ensures that the flue gas is maintained at a temperature exceeding 850 °C for a retention period of over 2 seconds. One portion of the flue gas generated in the secondary combustion chamber 4 is introduced into the diversion chamber 6 through the guide plate 13, and the other portion of the flue gas is discharged from the secondary combustion chamber outlet flue duct 5. (6) The diversion chamber 6 is separated from the secondary combustion chamber 4 by the refractory materials. After entering the diversion chamber 6, the high-temperature flue gas is passed through the flue gas nozzles 12 located on three layers in sequence and then introduced into different positions of the drying pyrolysis chamber 1.

[0081] Furthermore, the diameters of the flue gas nozzles located on three layers are increased step by step from top to bottom. The quantities of the flue gas of the high-temperature flue gas entering the different positions of the drying pyrolysis chamber 1 are basically the same through varying the diameters of the flue gas nozzles 12, so that the waste in the entire drying pyrolysis chamber 1 can be dried more evenly.

[0082] Furthermore, the position of the guide plate 13 is moveable, so as to adapt to the moisture content of different waste. The specific control method is as follows.

[0083] The element components of the waste at the entrance of the drying pyrolysis chamber 1 are defined as C ar , H ar , O ar , N ar and S ar , and the moisture of the waste is defined as M ar .

[0084] The mass, moisture content, heat value and temperature of the waste at the inlet of the drying pyrolysis chamber 1 are defined as m 1 , w 1 , Q 1 and t 1 , respectively.

[0085] The mass, moisture content, heat value and temperature of the waste at the outlet of drying pyrolysis chamber 1 are defined as m 2 , w 2 , Q 2 and t 2 , respectively.

[0086] The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are defined as t 3 and t 4 , respectively.

[0087] The specific heat capacities of the waste, water, water vapor, and high-temperature flue gas are defined as c 1 , c 2 , c 3 , and c 4 , respectively.

[0088] The excess air coefficient in the incinerator is defined as α.

[0089] The latent heat of the vaporization of water is defined as q.

[0090] The pressures at the secondary combustion chamber 4, the diversion chamber 6, and the secondary combustion chamber outlet flue 5 are defined as P, P 1 , and P 2 , respectively.

[0091] The distance between the guide plate 13 and the left side of the secondary combustion chamber 4 is defined as L 1 , and the distance between the guide plate 13 and the right side of the secondary combustion chamber 4 is defined as L 2 .

[0092] The quantity of the flue gas introduced from the secondary combustion chamber 4 to the diversion chamber 6 is defined as V 1 , and the quantity of the flue gas introduced from the secondary combustion chamber 4 to the secondary combustion chamber outlet flue 5 is defined as V 2 .

[0093] Then, the heat required by the drying pyrolysis chamber 1 for is H 1 = m 1 − m 2 q + c 1 m 1 1 − w 1 t 2 − t 1 + c 2 m 1 w 1 100 − t 1 + c 3 m 1 − m 2 t 4 − 100 .

[0094] The quantity of the high-temperature flue gas required to be introduced into the drying pyrolysis chamber 1 is V 1 = m 1 − m 2 q + c 1 m 1 1 − w 1 t 2 − t 1 + c 2 m 1 w 1 100 − t 1 + c 3 m 1 − m 2 t 4 − 100 c 4 t 3 − t 4

[0095] The quantity of the flue gas generated by the combustion of the secondary combustion chamber 4 is V y = m 1 1 × 10 − 6 + 0.0903 α C ar + 7 × 10 − 6 + 0.0338 α S ar + 0.05535 + 0.2693 α H ar + 0.006993 − 0.0338 α O ar + 0.008 N ar + 0.0124 M ar

[0096] The following equation is tenable through modulating the position of the guide plate 13 and the power of the induced draft fan (7), V 1 V y = P − P 1 L 1 P − P 2 L 2

[0097] The control method for a small-scale domestic waste incinerator can be obtained through substituting Formulas (1) and (2) into Formula (3), L 1 and L 2 are varied through modulating the position of the guide plate (13), and P 1 and P 2 are varied through modulating the power of the induced draft fan (7), finally Formula (3) is tenable, so that the quantity of the high-temperature flue gas entering the drying pyrolysis chamber satisfy the heat required for reducing the moisture content of the waste from w 1 to w 2 .

[0098] This control method can adapt to the situations of the variations in different waste components. When the moisture content of the waste is varied, the quantity of the high-temperature flue gas entering the drying pyrolysis chamber 1 is varied by modulating the position of the guide plate 13 and the power of the induced draft fan 7, and finally the moisture content and heat value for the waste entering the grate assembly 2 are kept constant.

[0099] In the device and the control method, the complex and variable waste can be converted into the waste with stable moisture content and the heat value, so that the stability of the combustion in the incinerator is ensured. And the moisture content of the waste is reduced and the heat value for the waste is increased through setting a drying pyrolysis chamber 1, so that the incineration temperature is increased and the requirement of 850 °C for at least 2 seconds can be satisfied without supplementing fuel. In this method, the distribution of the high-temperature flue gas generated by the secondary combustion chamber 4 can be quantitatively controlled, so that the heat value for the dried waste can be controlled more accurately, and the automatic control is implemented.Embodiment 1

[0100] The components of the original waste are as indicated in the following table: Component NameC ar H ar O ar N ar S ar M ar Numerical Value / %182100.70.560

[0101] The heat value for the original waste is 1343 kcal / kg.

[0102] It is required to increase the heat value for the waste entering the furnace to 2000 kcal / kg by drying in the pyrolysis chamber 1. The moisture content of the waste entering the furnace is 46.5%.

[0103] The treatment scale of the small-scale domestic waste is 500 kg / h, and the temperature of the original waste is 20 °C.

[0104] The temperature of the waste at the outlet of the drying pyrolysis chamber 1 is 300 °C and the mass flow rate is 374 kg / h.

[0105] The excess air coefficient of the incinerator is 1.4.

[0106] The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are 1050 °C and 200 °C, respectively.

[0107] The pressures in the secondary combustion chamber 4, the induced draft chamber 6 and the secondary combustion chamber outlet flue 5 are respectively -100 kPa, -300 kPa, and -250 kPa through the control of the induced draft fan 7.The position of the guide plate 13 is required to be modulated, so that L 1 / L 2 =0.214.

[0108] The position of the guide plate and the power of the induced draft fan 7 are modulated according to the above method, so that the heat value for the waste entering the furnace can be 2000 kcal / kg.Embodiment 2

[0109] When the components of the original waste are varied, and the components are as indicated in the following table: Component nameC ar H ar O ar N ar S ar M ar Numerical value / %202.5121.00.750

[0110] At this time, the heat value for the original waste is 1641 kcal / kg.

[0111] The waste is still required to be dried through the drying pyrolysis chamber 1 to increase the heat value for the waste entering the furnace to 2000 kcal / kg, and the moisture content of the waster entering the furnace is 42.0 %.

[0112] The treatment scale of small-scale domestic waste treatment is still 500 kg / h, and the temperature of the original waste is 20 °C.

[0113] The temperature of the waste at the outlet of the drying pyrolysis chamber 1 is 300 °C and the mass flow rate is 431 kg / h.

[0114] The excess air coefficient of the incinerator is 1.4.

[0115] The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are 1050 °C and 200 °C, respectively.

[0116] The pressures in the secondary combustion chamber 4, the induced draft chamber 6 and the secondary combustion chamber outlet flue 5 are respectively -100 kPa, -300 kPa, and -250 kPa through the control of the induced draft fan 7.

[0117] The position of the guide plate 13 is required to be modulated, so that L 1 / L 2 =0.154.

[0118] The position of the guide plate 13 and the power of the induced draft fan 7 are modulated according to the above method, so that the heat value for the waste entering the furnace can be 2000 kcal / kg.

[0119] In comparison with Embodiment 1, when the moisture content of the original waste is reduced and the heat value for the original waste is increased, and the pressures in the secondary combustion chamber 4, the draft chamber 6 and the secondary combustion chamber outlet flue 5 are kept unvaried after modulating the induced draft fan 7, then the guide plate 13 is required to be moved towards the diversion chamber 6 to reduce the quantity of the flue gas entering the drying pyrolysis chamber 1.Embodiment 3

[0120] When the components of the original waste are varied, and the components are as indicated in the following table: Component nameC ar H ar O ar N ar S ar M ar Numerical value / %222.7131.20.840

[0121] At this time, the heat value for the original waste is 1889 kcal / kg.

[0122] The waste is still required to be dried through the drying pyrolysis chamber 1 to increase the heat value for the waste entering the furnace to 2000 kcal / kg, and the moisture content of the waster entering the furnace is 37.3 %.

[0123] The treatment scale of small-scale domestic waste is still 500 kg / h, and the temperature of the original waste is 20 °C.

[0124] The temperature of the waste at the outlet of the drying pyrolysis chamber 1 is 300 °C and the mass flow rate is 478 kg / h.

[0125] The excess air coefficient of the incinerator is 1.4.

[0126] The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are 1050 °C and 200 °C, respectively.

[0127] The pressures in the secondary combustion chamber 4, the induced draft chamber 6, and the secondary combustion chamber outlet flue 5 are respectively -100 kPa, -300 kPa, and -250 kPa through the control of the induced draft fan 7.

[0128] The position of the guide plate 13 is required to be modulated, so that L 1 / L 2 =0.110.

[0129] The position of the guide plate 13 and the power of the induced draft fan 7 are modulated according to the above method, so that the heat value for the waste entering the furnace can be reached 2000 kcal / kg.

[0130] In comparison with Embodiment 2, when the moisture content of the original garbage is further reduced and the heat value is increased, and the pressures in the secondary combustion chamber 4, the diversion chamber 6, and the secondary combustion chamber outlet flue 5 are kept unvaried after modulating the induced draft fan 7, the guide plate 13 is further required to be moved towards the diversion chamber 6 to reduce the quantity of the flue gas entering the drying pyrolysis chamber 1.

[0131] The above descriptions are merely the preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. A technician familiar with the technical field can make equivalent replacements or variations according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Examples

embodiment 1

[0100]The components of the original waste are as indicated in the following table:

Component NameC ar H ar O ar N ar S ar M ar

Numerical Value / %182100.70.560

[0101]The heat value for the original waste is 1343 kcal / kg.

[0102]It is required to increase the heat value for the waste entering the furnace to 2000 kcal / kg by drying in the pyrolysis chamber 1. The moisture content of the waste entering the furnace is 46.5%.

[0103]The treatment scale of the small-scale domestic waste is 500 kg / h, and the temperature of the original waste is 20 °C.

[0104]The temperature of the waste at the outlet of the drying pyrolysis chamber 1 is 300 °C and the mass flow rate is 374 kg / h.

[0105]The excess air coefficient of the incinerator is 1.4.

[0106]The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are 1050 °C and 200 °C, respectively.

[0107]The pressures in the secondary combustion chamber 4, the induced draft chamber 6 and the secondary c...

embodiment 2

[0109]When the components of the original waste are varied, and the components are as indicated in the following table:

Component nameC ar H ar O ar N ar S ar M ar

Numerical value / %202.5121.00.750

[0110]At this time, the heat value for the original waste is 1641 kcal / kg.

[0111]The waste is still required to be dried through the drying pyrolysis chamber 1 to increase the heat value for the waste entering the furnace to 2000 kcal / kg, and the moisture content of the waster entering the furnace is 42.0 %.

[0112]The treatment scale of small-scale domestic waste treatment is still 500 kg / h, and the temperature of the original waste is 20 °C.

[0113]The temperature of the waste at the outlet of the drying pyrolysis chamber 1 is 300 °C and the mass flow rate is 431 kg / h.

[0114]The excess air coefficient of the incinerator is 1.4.

[0115]The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are 1050 °C and 200 °C, respectively.

[0116]Th...

embodiment 3

[0120]When the components of the original waste are varied, and the components are as indicated in the following table:

Component nameC ar H ar O ar N ar S ar M ar

Numerical value / %222.7131.20.840

[0121]At this time, the heat value for the original waste is 1889 kcal / kg.

[0122]The waste is still required to be dried through the drying pyrolysis chamber 1 to increase the heat value for the waste entering the furnace to 2000 kcal / kg, and the moisture content of the waster entering the furnace is 37.3 %.

[0123]The treatment scale of small-scale domestic waste is still 500 kg / h, and the temperature of the original waste is 20 °C.

[0124]The temperature of the waste at the outlet of the drying pyrolysis chamber 1 is 300 °C and the mass flow rate is 478 kg / h.

[0125]The excess air coefficient of the incinerator is 1.4.

[0126]The inlet temperature and outlet temperature of the high-temperature flue gas in the drying pyrolysis chamber 1 are 1050 °C and 200 °C, respectively.

[0127]The pressure...

Claims

1. A small-scale domestic waste incinerator, characterized in that the incinerator comprises a drying pyrolysis chamber (1) and a combustion chamber (3) arranged over a grate assembly (2) of the waste incinerator, wherein the drying pyrolysis chamber (1) is disposed at an upstream section of the grate assembly (2), and the combustion chamber (3) is disposed at a downstream section of the grate assembly (2); the drying pyrolysis chamber (1) is vertically oriented, an upper end of the drying pyrolysis chamber (1) is a waste inlet, and a lower end of the drying pyrolysis chamber (1) is a waste outlet, and one part of the grate assembly (2) is covered by the waste outlet of the drying pyrolysis chamber (1); the grate assembly (2) is enclosed by the combustion chamber (3), and a secondary combustion chamber (4) is in communication with an upper portion of the combustion chamber (3), and a pyrolysis gas nozzle (9) is mounted on a side wall of the combustion chamber (3) in proximity to an upper section of the drying pyrolysis chamber (1); a drying pyrolysis chamber outlet flue duct (14) with an induced draft fan (7) is provided on a side wall of the drying pyrolysis chamber (1) in proximity to an upper end of the drying pyrolysis chamber (1), and the drying pyrolysis chamber outlet flue duct (14) is in connection with the pyrolysis gas nozzle (9) through a condenser (8); a diversion chamber (6) is situated between a same side of the combustion chamber (3) and the secondary combustion chamber (4) and one side of the drying pyrolysis chamber (1), the diversion chamber (6) is sealed at a bottom end and a top end of the diversion chamber (6) is a flue gas inlet, a side part of the drying pyrolysis chamber (1) is provided with a plurality of flue gas nozzles (12) along a longitudinal direction, and the flue gas nozzles (12) are in communication with the diversion chamber (6); a secondary combustion chamber outlet flue duct (5) and a circulating flue duct are respectively arranged on both sides of a top part of the secondary combustion chamber (4), the circulating flue duct is in communication with the flue gas inlet of the diversion chamber (6), and a guide plate (13) configured to regulate quantities of flue gas directed into the secondary combustion chamber outlet flue duct (5) and the circulating flue duct is installed on the top part of the secondary combustion chamber (4).

2. The small-scale domestic waste incinerator according to claim 1, characterized in that, calibers of the plurality of flue gas nozzles (12) are sequentially increased from top to bottom.

3. The small-scale domestic waste incinerator according to claim 2, characterized in that, three sealing gates (10) are arranged at the waste inlet of the drying pyrolysis chamber (1), and a switch plate (11) is arranged at the waste outlet.

4. The small-scale domestic waste incinerator according to claim 3, characterized in that, the grate assembly (2) is formed by slidable grates and fixed grates, and the slidable grates and the fixed grates are arranged in an alternating sequence.

5. The small-scale domestic waste incinerator according to claim 4, characterized in that, the waste outlet of the drying pyrolysis chamber (1) is sealed by a first-stage slidable grate of the grate assembly (2), and the slidable grate is further taken as a feeding grate.

6. A method for using the small-scale domestic waste incinerator according to claim 5, characterized in that, the method comprises following steps: Step 1, adding, by a bucket elevator, waste to the drying pyrolysis chamber (1) after being sorted and crushed; Step 2, introducing high-temperature flue gas produced by a combustion in the secondary combustion chamber (4) through the plurality of flue gas nozzles (12) on the side wall of the drying pyrolysis chamber (1); performing, under a heating of the high-temperature flue gas, a drying and a pyrolysis reaction on the waste in the drying pyrolysis chamber (1) to generate water vapor and a small quantity of combustible gas; introducing the generated water vapor and the small quantity of combustible gas into the high-temperature flue gas and discharging from the drying pyrolysis chamber outlet flue duct (14); Step 3, enabling, dried waste to be fallen from the waste outlet onto the grate assembly (2); transporting, with a pushing of the slideable grate in the grate assembly (2), the waste downstream; completing, when the waste is passed through the fixed grate in the grate assembly (2) and fallen off, a turning-over; discharging bottom slags produced by a combustion of the waste from a slag outlet of the grate assembly (2); and introducing the flue gas produced by the combustion into the combustion chamber; Step 4, supplying, from beneath grate assembly (2), a primary air into the combustion chamber (3); and introducing, through an opening of a furnace rear arch, a secondary air, completely mixing, under an action of the secondary air, the flue gas to ensure a complete combustion; Step 5, condensing, through the condenser (8), the flue gas produced by the pyrolysis chamber (1) into dry flue gas; recirculating the dry flue gas into the combustion chamber (3) via the pyrolysis gas nozzle (9) to completely combust a small quantity of combustible gas, wherein condensed water produced by the condenser (8) can be utilized as makeup water for a quench tower; and Step 6, introducing the flue gas generated in the combustion chamber (3) into the secondary combustion chamber (4) to ensure that the flue gas is maintained at a temperature exceeding 850 °C for a retention period of over 2 seconds; splitting, by the guide plate (13), the flue gas produced by the secondary combustion chamber (4), wherein one portion of the flue gas is diverted to the diversion chamber (6) and another portion of the flue gas is discharged through the secondary combustion chamber outlet flue duct (5); and Step 7, introducing, after the high-temperature flue gas enters the diversion chamber (6), the high-temperature flue gas into positions at different heights of the drying pyrolysis chamber (1) after passing through the plurality of flue gas nozzles (2) in sequence.

7. The method for using the small-scale domestic waste incinerator according to claim 6, characterized in that, in Step 1, three sealing gates (10) are arranged at the waste inlet of the drying pyrolysis chamber (1), during adding the waste, firstly, the first sealing gate (10) is opened to receive the waste, then closed, subsequently, the second sealing gate (10) is opened, then closed, finally, the third sealing gate (10) is opened to allow the waste to enter the drying pyrolysis chamber (1).

8. The method for using the small-scale domestic waste incinerator according to claim 6, characterized in that, in Step 3, the dried waste is discharged from the waste outlet to the grate assembly (2), and the waste is fallen smoothly by rotating the switch plate (11) to flip up and down.

9. The method for using the small-scale domestic waste incinerator according to claim 6, characterized in that, in Step 6, quantities of the flue gas between the diversion chamber (6) and the secondary combustion chamber outlet flue duct (5) are regulated by modulating an installation position of the guide plate (13), and an adjustment process is that: element components of the waste entering the drying pyrolysis chamber are defined as Car, Har, Oar, Nar and Sar, and a moisture of the waste is defined as Mar; a mass, a moisture content, a heat value and a temperature of the waste entering the drying pyrolysis chamber (1) are defined as m1, w1, Q1 and t1, respectively; a mass, a moisture content, a heat value and a temperature of the waste discharging from the drying pyrolysis chamber (1) are defined as m2, w2, Q2 and t2, respectively; a temperature of the flue gas entering the drying pyrolysis chamber (1) from the flue gas nozzle (12) is defined as t3 and a temperature of the flue gas entering the drying pyrolysis chamber outlet flue duct (14) from the drying pyrolysis chamber (1) is defined as t4; specific heat capacities of the waste, water, water vapor, and high-temperature flue gas are defined as c1, c2, c3, and c4, respectively; an excess air coefficient in the incinerator is defined as α; a latent heat of a vaporization of water is defined as q; pressures at the secondary combustion chamber (4), the diversion chamber (6), and the secondary combustion chamber outlet flue (5) are defined as P, P1, and P2, respectively; a distance between the guide plate (13) and a flue opening leading to the diversion chamber (6) is defined as L1, and a distance between the guide plate (13) and a flue opening leading to the secondary combustion chamber outlet flue (5) is defined as L2; and a quantity of the flue gas entering the diversion chamber (6) from the secondary combustion chamber (4) is defined as V1, and a quantity of the flue gas entering the secondary combustion chamber outlet flue (5) from the secondary combustion chamber (4) is defined as V2; then a heat required by the drying pyrolysis chamber (1) is H 1 = m 1 − m 2 q + c 1 m 1 1 − w 1 t 2 − t 1 + c 2 m 1 w 1 100 − t 1 + c 3 m 1 − m 2 t 4 − 100 , a quantity of the high-temperature flue gas required to be introduced into the drying pyrolysis chamber 1 is V 1 = m 1 − m 2 q + c 1 m 1 1 − w 1 t 2 − t 1 + c 2 m 1 w 1 100 − t 1 + c 3 m 1 − m 2 t 4 − 100 c 4 t 3 − t 4 a quantity of the flue gas produced by a combustion of the secondary combustion chamber (4) is V y = m 1 1 × 10 − 6 + 0.0903 α C ar + 7 × 10 − 6 + 0.0338 α S ar + 0.05535 + 0.2693 α H ar + 0.006993 − 0.0338 α O ar + 0.008 N ar + 0.0124 M ar and a following equation is tenable through modulating a position of the guide plate (13) and a power of the induced draft fan (7) V 1 V y = P − P 1 L 1 P − P 2 L 2 and a control method for a small-scale domestic waste incinerator is obtained through substituting Formulas (1) and (2) into Formula (3), L1 and L2 are varied through modulating the position of the guide plate (13), and P1 and P2 are varied through modulating the power of the induced draft fan (7), finally Formula (3) is tenable, so that the quantity of the high-temperature flue gas entering the drying pyrolysis chamber (1) satisfy the heat required for reducing the moisture content of the waste from w1 to w2.

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