Method for producing synthesis gas by oxygen thermal method for garbage melting and gasification and garbage melting gasification furnace

Abstract

The present invention relates to a method for oxy-thermal melting and gasification of waste to produce syngas and a waste melting gasification furnace. The waste gasification furnace includes a gasification reaction chamber in the upper section, a reaction melting chamber and a melting pool in the lower section. The upper section of the reaction melting chamber is connected to a pyrolysis channel. The top of the gasification reaction chamber is connected to a quench chamber through a connection channel. The melting pool is communicated with a slag water cooling pool through a slag discharge port downcomer. Among them, the reaction melting chamber is provided with a plurality of melting burners. The nozzle of the melting burner consists of a central oxygen lance and an outer peripheral nozzle. Oxygen is ejected from the central oxygen lance, and auxiliary oxygen and fuel are ejected from the outer peripheral nozzle and mixed in the reaction melting chamber. The oxygen flow rate ejected from the central oxygen lance is controlled to be ≥200 m / s. The process of the present invention is simple, has high gasification efficiency, low emissions, low equipment investment and operation costs, long equipment service life, and energy conservation and consumption reduction. It is particularly suitable for the reduction, harmless treatment and resource utilization of compressed blocky waste materials.

Description

Technical Field

[0001] The present invention relates to the field of waste gasification, and specifically to a method for oxygen thermal method waste melting and gasification to produce syngas and a waste melting gasification furnace. Background Art

[0002] In order to meet the requirements of waste reduction, harmlessness and resource utilization, and achieve zero discharge of three wastes, advanced developed countries in the world such as Japan, the United States, the United Kingdom, Germany, etc. adopt plasma melting or oxygen-enriched melting technology to treat waste. However, due to the high requirements for refractory materials in high-temperature melting treatment and the short service life of plasma guns or burners, there are few commercially successful operating devices at present.

[0003] It can be seen that due to the diversity, complex composition, different calorific values, different salt contents, water content, and large changes in ash content of waste, it is difficult to select a process device with wide waste adaptability, short process flow, low equipment investment, no "three wastes" discharge, and capable of obtaining high-quality syngas for downstream processes. In particular, it is difficult to find a key device for waste melting treatment - a waste melting gasification furnace that can adapt to the incomplete classification in China and operate stably for a long period. Solving the problems of materials and structures resistant to high-temperature molten slag erosion and corrosion of the waste melting gasification furnace, the long service life of burners for melting gasification, blockage of high-temperature molten slag discharge, and ash accumulation in the syngas channel is the direction that those skilled in the art have been committed to researching.

[0004] Publication No. 109210541A discloses a two-stage waste melting gasification furnace, including a gasification chamber in the upper section and a melting incineration chamber in the lower section. The melting incineration chamber is connected to the gasification chamber through a throat; waste feed inlets are respectively provided on the gasification chamber and the melting incineration chamber, and an oxygen nozzle is provided on the melting incineration chamber; a slag discharge port is provided at the bottom of the waste melting chamber, and the gas outlet at the top of the gasification chamber is connected to a cyclone separator through a conduit. The return feeder at the bottom of the cyclone separator is connected to the melting incineration chamber through a return leg. This technical solution realizes the limited separation of waste melting incineration and gasification through a two-stage design, completely separates toxic and harmful substances in the waste, and the bottom slag of the waste can be recycled in the form of glass slag. However, there are still the following problems:

[0005] (1) The waste raw materials in the above solution are directly fed into the feeding device from the large bin after being crushed, which is a relatively loose state of material, easy to fully contact and react with oxygen, and realize the full combustion of oxygen and pyrolysis slag, so as to ensure the temperature of the reaction melting chamber; however, the energy density of the waste is low, and the required incineration melting chamber is large. Evaporation of a large amount of water requires consuming a large amount of heat generated by the reaction of oxygen and carbon-containing substances, resulting in high energy consumption and low content of effective gas components in the generated syngas.

[0006] (2) The side wall of the gasification reaction chamber is usually provided with gasification burners to inject oxygen-enriched air or pure oxygen to pyrolyze the garbage, causing a reduction reaction to generate high-temperature syngas and maintaining the temperature inside the gasification reaction chamber. However, it is found in operation that during the start-up and heating process of the gasifier, due to the instability of the garbage composition and high water content, it is difficult for the outlet temperature of the gasification reaction chamber to quickly stabilize above 900 °C, which will cause harmful substances such as dioxins to be carried in the syngas leaving the gasification reaction chamber, resulting in problems such as long start-up time and high energy consumption.

[0007] (3) The high-temperature syngas leaving the gasification reaction chamber is either sent to a wet dust collector to obtain black water or directly sent to a cyclone separator for dust removal by dry dust removal. The dust content in the black water obtained by wet dust removal is much higher than that in the coal gasification process, and the post-treatment process is complex and the cost is extremely high, which is not conducive to environmental protection; although high-temperature dry dust removal can recover dry powder, since the treatment object is high-temperature syngas above 1000 °C, this requires extremely high high-temperature resistance performance for the cyclone separator and has a short service life, resulting in an increase in equipment investment and operating costs.

[0008] (4) The high-temperature syngas leaving the gasification reaction chamber is directly sent to a cyclone separator for dust removal. Although some dry powder can be recovered, most of the ash carried in the gas has a particle size less than 10 microns, and the dust removal efficiency of the cyclone separator is low, resulting in particular difficulties for the downstream wastewater treatment system. Summary of the Invention

[0009] The purpose of the present invention is to solve the above technical problems and provide a method for oxygen-thermal garbage melting and gasification to produce syngas with simple method, high reaction efficiency, good reliability, low equipment investment and operating costs, and low energy consumption.

[0010] The present invention also provides a garbage melting gasifier with simple structure, easy to control, low investment and operating costs, and long service life.

[0011] In the method for oxygen-thermal garbage melting and gasification to produce syngas of the present invention, the garbage packages compressed into blocks are sent into the pyrolysis channel of the gasifier for pyrolysis. The pyrolysis gas generated by the garbage pyrolysis rises upward into the gasification reaction chamber for a reduction reaction to generate high-temperature syngas. The high-temperature syngas enters the quench chamber from the top of the gasification reaction chamber through a connecting channel and is cooled to 120 - 180 °C before leaving the gasifier; the remaining solid substances after the garbage pyrolysis reaction fall downward into the reaction melting chamber to react with oxygen, generating high-temperature gas that rises into the gasification reaction chamber. The liquid slag formed by the high-temperature melting of the solid substances enters the melting pool and continues to react with the unreacted carbon-containing substances in the slag at high temperature. Finally, it falls into the slag pool through the slag discharge port downcomer and then leaves the gasifier;

[0012] Among them, a plurality of melting burners are evenly arranged in the reaction melting chamber. The nozzle of the melting burner includes a central oxygen lance and an outer nozzle. The central oxygen lance ejects oxygen, and the outer nozzle ejects auxiliary oxygen and fuel. The flow rate of the oxygen ejected by the central oxygen lance is controlled to be ≥200 m / s, and the flow rate of the oxygen and fuel ejected by the outer nozzle is 20 - 50 m / s.

[0013] The raw syngas cooled out of the gasifier is further separated by bag dust removal to obtain cooled syngas and dry ash; the dry ash is collected and sprayed into the reaction melting chamber together with the gas through an ash / gas lance. A top-blowing burner vertically downward is arranged at the top of the gasification reaction chamber, and the flow rate of the gas ejected by the top-blowing burner is controlled to be 10 - 30 times the average flow rate of the syngas in the cross-section of the gasification reaction chamber.

[0014] The high-temperature syngas is first cooled to below 200 °C by the pressure atomizing water nozzles in the upper layer in the quench chamber, and then cooled to 120 - 180 °C by the water / gas atomizing nozzles in the lower layer.

[0015] The reaction temperature in the gasification chamber is 1200 °C - 1400 °C, and the reaction residence time of the pyrolysis gas in the gasification chamber is 2 - 5 s.

[0016] The temperature of the molten slag flowing from the molten pool into the slag discharge port is greater than or equal to 1550 °C.

[0017] The waste melting gasifier of the present invention includes an upper gasification reaction chamber, a lower reaction melting chamber and a molten pool. It is characterized in that the upper section of the reaction melting chamber is connected to a pyrolysis channel, the top of the gasification reaction chamber is connected to a quench chamber through a connection channel, and the molten pool is connected to a slag water cooling pool through a slag discharge port and a downcomer. Among them, the reaction melting chamber is provided with a plurality of melting burners. The nozzle of the melting burner includes a central oxygen lance and an outer nozzle. The central oxygen lance ejects oxygen, and the outer nozzle ejects auxiliary oxygen and fuel. The flow rate of the oxygen ejected by the central oxygen lance is controlled to be ≥200 m / s, and the flow rate of the oxygen and fuel ejected by the outer nozzle is 20 - 50 m / s.

[0018] The melting burner of the reaction melting chamber is a three-channel burner, and its injection angle is inclined downward at an angle of 15 0 ~25 0 with the horizontal direction, and the radial angle is 0 0 .

[0019] A plurality of gasification burners are arranged in the gasification reaction chamber. The injection angle of the gasification burner is downward at an angle of 15 0 ~25 0 with the horizontal direction, and the radial angle is 20 0 .

[0020] The top of the gasification reaction chamber is provided with a top-blown burner vertically downward, and the gas flow rate ejected from the top-blown burner is 10 - 30 times the average flow rate of the syngas in the cross-section of the gasification reaction chamber.

[0021] The ash / gas lance is also provided in the reaction melting chamber.

[0022] The quench chamber is provided with a pressure atomizing water nozzle in the upper layer and a water / gas atomizing nozzle in the lower layer. The diameter of the water mist ejected from the pressure atomizing water nozzle is 1 - 3 mm, and the diameter of the water mist ejected from the water / gas atomizing nozzle is...

[0023] An ash remover is provided at the entrance of the quench chamber, and a slag breaker is provided at the lower section of the slag discharge port downcomer.

[0024] The pyrolysis channel is of a gradually expanding structure.

[0025] The wall surface of the reaction melting chamber is a copper water jacket cooling wall, and high-Cr refractory bricks or castables are inlaid on the surface of the copper water jacket cooling wall.

[0026] The reaction melting pool is an oblong dome channel surrounded by high-Cr refractory bricks.

[0027] The outlet end of the melting pool is of a gradually shrinking structure.

[0028] The syngas cooled by spraying water is further separated by bag dust removal to obtain clean syngas and dry ash; the dry ash is collected and sprayed into the reaction melting chamber through the ash / gas lance. In order to ensure that the pyrolysis gas and the dust carried by it are fully cracked, the reaction temperature in the gasification chamber is 1200 °C - 1400 °C, and the pyrolysis gas and particulate matter are fully mixed in this interval, and the reaction residence time in the gasification chamber is 2 - 5 s to completely eliminate dioxins. In order to adapt to the melting of different materials and flow smoothly into the downcomer and slag pool, the temperature of the molten slag flowing from the melting pool into the slag discharge port is greater than or equal to 1550 °C.

[0029] In view of the problems existing in the background technology, the inventor makes the following improvements:

[0030] (1) Using compressed garbage bags in the form of blocks to replace the existing loose garbage is a good way to increase the energy density of garbage and reduce the volume of the gasifier. However, the density of the compressed garbage bags is high, and after pyrolysis, they continuously fall into the reaction melting chamber, forming a thick stockpile layer, which makes it difficult for the garbage in the central part to participate in the reaction and seriously affects the reaction efficiency. Therefore, the inventor also evenly installs a plurality of melting burners in the reaction melting chamber. The melting burner has a central oxygen injection gun and an outer nozzle. The slow-speed oxygen and fuel gas ejected through the outer nozzle are mixed in the reaction melting chamber for combustion to maintain the temperature in the reaction melting chamber. Then, high-speed oxygen is ejected through the central oxygen injection gun. By skillfully controlling the oxygen flow rate ejected by the central oxygen injection gun to be ≥200 m / s, it is ensured that the oxygen energy efficiency can effectively penetrate into the stockpile layer, fully contact and react with the pyrolysis slag, improve the reaction efficiency, and can generate a high temperature of up to more than 2000 °C. The flow rate of oxygen and fuel ejected by the outer nozzle is 20 - 50 m / s to ensure that the flame does not go out and continues to burn; further, control the injection angle of the plurality of melting burners to be downward and the included angle with the horizontal direction is 15 0 ~25 0 , and the radial included angle is 0 0 , to further improve the penetration efficiency of oxygen into the stockpile layer and improve the reaction efficiency.

[0031] (2) During the start-up and heating process of the gasifier, due to the unstable composition and large calorific value change of the garbage, it is difficult for the temperature of the dust-containing high-temperature gas in the gasification reaction chamber to quickly stabilize at 1200 °C - 1400 °C. Therefore, a top-blowing burner is installed vertically downward at the top of the gasification reaction chamber. On the one hand, by setting the top-blowing burner, the gasification reaction chamber can be quickly heated up at the initial stage of the gasifier start-up, ensuring that the outlet temperature reaches more than 1000 °C and more than 1200 °C during normal operation, minimizing the entry of harmful substances such as dioxins into the downstream process with the syngas and greatly reducing the energy consumption during the gasifier heating period; on the other hand, by setting the top-blowing burner, fuel and oxygen are ejected vertically downward. Preferably, control the gas flow rate ejected by the top-blowing burner to be 10 - 30 times the average flow rate of the syngas in the cross-section of the gasification reaction chamber. Cooperating with the gasification burners on the side wall of the gasification reaction chamber, the rising high-temperature syngas can form a violent turbulence here, achieving the purpose of extending the residence time of the syngas and reducing the dust carried by the syngas and the carbon content of the dust.

[0032] (3) In order to rapidly cool the high-temperature syngas and avoid the resynthesis of dioxins at 200 - 500 °C, it is necessary to quickly reduce the temperature of the syngas below 200 °C, but not too low. If the temperature drops below 100 °C, free water will precipitate, which is not suitable for dry dust removal. At the same time, due to the unstable types and components of garbage, the calorific value and moisture content change, resulting in unstable gas volume of the syngas and difficult temperature control. Therefore, upper and lower layers of nozzles are arranged in the quench chamber. The upper pressure atomized water nozzle has good quenching efficiency, the water mist diameter is 1 - 3 mm, and it can quickly reduce the temperature of the high-temperature syngas to below 200 °C in the quench chamber. However, its temperature control and regulation ability is poor. The lower water / gas atomized nozzle can easily achieve relatively precise control of the syngas temperature according to the change of the syngas volume. The water mist diameter is 40 - 150 μm, and it can further cool the temperature to 120 - 180 °C, meeting the inlet requirements of dry dust removal, without the need for high-temperature-resistant dust collectors, greatly reducing the equipment investment and operation cost. Considering that the water in the water spraying area contacts the high-temperature syngas, the water reacts with ash, and hard ash is easily formed after sintering and adheres to the syngas channel. Therefore, an ash remover is arranged at the inlet of the quench chamber to timely remove the ash and slag accumulated in the water spraying area of the quench chamber.

[0033] (4) As mentioned above, since the garbage raw material is compressed blocky material, when pyrolyzing in the pyrolysis channel, it is desired to make it as loose as possible through slow pyrolysis. And in order to adapt to the thermal expansion during the garbage pyrolysis process, the pyrolysis channel is preferably of a gradually expanding structure to avoid garbage blocking the pyrolysis channel. On the other hand, considering that during the flow process of the molten slag flowing towards the molten pool, the flow direction and flow pattern change, and the molten slag severely erodes the square-section molten pool. Therefore, the molten pool is designed as an oval dome channel surrounded by high-Cr refractory bricks, which greatly reduces the erosion of the side wall of the molten pool and extends the service life of the equipment. Further, in order to ensure the smooth flow of the high-temperature molten slag and avoid slag blockage, the outlet end of the molten pool is of a gradually shrinking structure. By reducing the cross-sectional area, the local flow rate of the molten slag is increased, so that it quickly drops from the molten pool through the slag discharge port downcomer into the slag pool, avoiding the situation that the flow rate of the molten slag is too low and the flow time is long, resulting in the reduction of the molten slag temperature and the increase of the molten slag viscosity, thus forming slag blockage. Since the viscosity of the molten slag is related to its composition and temperature, sometimes it is inevitable to form icicle-shaped flowing slag. Preferably, a slag breaker is arranged in the lower section of the slag discharge port downcomer to timely remove the slag.

[0034] (5) In order to solve the problem that the refractoriness of ordinary refractory bricks does not exceed 1850 °C and the actual allowable maximum use temperature cannot exceed 1650 °C, the wall surface of the reaction melting chamber of the present invention is a copper water jacket cooling wall, and high-Cr refractory bricks or castables are inlaid on the surface of the copper water jacket cooling wall, which can not only control the temperature of the refractory bricks below 1650 °C, but also reduce the heat carried away by the cooling medium of the copper water jacket cooling wall, achieving the purpose of energy conservation and consumption reduction, and greatly improving the overall life of the gasifier.

[0035] (6) To ensure the full cracking of the pyrolysis gas and the dust it carries, the reaction temperature in the gasification chamber is set at 1200°C to 1400°C. The pyrolysis gas and particulate matter are fully mixed in this temperature range, and the reaction residence time in the gasification chamber is 2 to 5 seconds to completely eliminate dioxins. To adapt to the melting of different materials and ensure smooth flow into the downcomer and slag pool, the temperature of the molten slag flowing from the melting pool into the slag discharge port is greater than or equal to 1550°C.

[0036] Beneficial effects:

[0037] The process of the present invention is simple, can effectively recover carbon raw materials, has high gasification efficiency, small equipment volume, low investment and operation costs, good operation stability, long equipment service life, and can save energy and reduce consumption. It is especially suitable for compressed blocky waste materials. Description of the drawings

[0038] Figure 1 It is a schematic structural diagram of the gasification furnace of the present invention.

[0039] Figure 2 It is Figure 1 the A-A cross-sectional view of

[0040] Figure 3 It is Figure 1 the B-B cross-sectional view of

[0041] Figure 4 It is Figure 1 the C-C cross-sectional view of

[0042] Figure 5 It is Figure 1 the D-direction view of

[0043] Figure 6 It is Figure 1 the H-direction view of

[0044] Figure 7 It is a schematic structural diagram of the melting burner.

[0045] Among them, 1 - pyrolysis channel, 2 - transition section, 3 - gasification reaction chamber, 4 - gasification burner, 5 - top-blowing burner, 6 - reaction melting chamber, 7 - melting burner, 7.1 - central oxygen injection lance, 7.2 - peripheral natural gas nozzle, 7.3 - peripheral auxiliary oxygen nozzle, 7.4 - water-cooled jacket, 8 - burner, 9 - melting pool, 10 - emergency nozzle, 11 - slag breaker, 12 - slag discharge port downcomer, 13 - slag skimmer, 14 - slag water cooling tank, 15 - connection channel, 16 - dust remover, 17 - pressure atomizing water nozzle, 18 - water / gas atomizing nozzle, 19 - quench chamber, 20 - ash / gas lance. Specific embodiments

[0046] The present invention will be further explained below with reference to the drawings:

[0047] See Figure 1 , the waste melting gasification furnace of the present invention includes a gasification reaction chamber 3 in the upper section, a reaction melting chamber 6 in the middle section, and a melting pool 9 in the lower section. The upper section of the reaction melting chamber 3 is connected to a pyrolysis channel 1. The top of the gasification reaction chamber 3 is connected to a quench chamber 19 through a connection channel 15. The outlet of the melting pool 9 is connected to a slag water cooling pool 14 through a slag discharge port downcomer 12. The gasification reaction chamber is connected to the reaction melting chamber 6 through a transition section 2.

[0048] Among them, see Figure 6 , the pyrolysis channel 1 is of a gradually expanding structure, and the waste can be indirectly heated to above 400 °C by a set electric heating device or high-temperature flue gas;

[0049] See Figure 3 , the reaction melting chamber 6 is provided with an ash / gas spray gun 20 and a plurality of melting burners 7. The ash / gas spray gun 20 sprays ash and fuel gas; the introduced ash is the dry ash separated from the quenched raw syngas; the nozzle of the melting burner 7 is at least composed of a central oxygen spray gun and an outer peripheral nozzle. Preferably, the melting burner 7 is a three-channel burner. See Figure 7 , from the center to the outer periphery, it includes a central oxygen spray gun 7.1 and two layers of outer peripheral nozzles, namely an outer peripheral natural gas nozzle 7.2 and an outer peripheral auxiliary oxygen nozzle 7.3, and the outermost water-cooled jacket 7.4. The central oxygen spray gun 7.1 sprays oxygen, the outer peripheral nozzle 7.2 sprays fuel gas, and the auxiliary oxygen nozzle 7.3 sprays auxiliary oxygen. The oxygen flow rate sprayed out by the central oxygen spray gun 7.1 is ≥200 m / s, which is used to penetrate the waste skeleton after pyrolysis and provide oxygen for the reaction. The flow rates of the oxygen and fuel sprayed out by the outer peripheral natural gas nozzle 7.2 and the outer peripheral auxiliary oxygen nozzle 7.3 are 20 - 50 m / s. The fuel gas and auxiliary oxygen are used to generate heat by combustion. See Figure 2 , the injection angle of the melting burner 7 is downward and the included angle with the horizontal direction is 15 0 ~25 0 , and the radial included angle is 0 0 . The wall surface of the reaction melting chamber 6 is a copper water jacket cooling wall, and a high-Cr refractory brick or castable is inlaid on the surface of the copper water jacket cooling wall.

[0050] A plurality of gasification burners 4 are evenly arranged on the side wall of the gasification reaction chamber 3 along the circumferential tangential direction, and their injection angles are inclined downward by 20 0 , and the radial included angle is 0 0 ~20 0 , the purpose is to enable the waste pyrolysis gas and tar to undergo a reduction reaction with oxygen and steam in this area, so that the tar is fully cracked to produce syngas. A top-blown burner 5 is provided at the top of the gasification reaction chamber 3.

[0051] In the quench chamber 19, there are pressure atomizing water nozzles 17 in the upper layer and water / gas atomizing nozzles 18 in the lower layer. The jet direction of the pressure atomizing water nozzles 17 is obliquely downward, with an angle of 30 - 60 degrees, preferably 45 degrees, with the horizontal direction, the jet cone angle is 75 - 150 degrees, and the Sauter Mean Diameter (SMD) of the sprayed water mist is 1 - 3 mm. The water / gas atomizing nozzles 18 can use different gases such as carbon dioxide, syngas, and nitrogen as the atomizing gas for water. Its jet direction is obliquely downward, with an angle of 30 - 60 degrees, preferably 45 degrees, with the horizontal direction, and the jet cone angle is 60 - 120 degrees. The SMD of the sprayed water mist is 40 - 150 μm. An ash remover 16 is provided at the entrance of the quench chamber 19.

[0052] See Figure 4 , the molten bath 9 is an oblong dome-shaped channel surrounded by high-Cr refractory bricks, and the outlet end is a tapered structure (see Figure 5 ). In order to maintain the temperature of the molten slag and enable the unreacted carbon in the molten slag to fully react with oxygen in the molten bath, multiple burners 8 are arranged on the side wall of the molten bath; in order to ensure the smooth flow of the high-temperature molten slag and avoid blockage of the molten slag, the molten slag pool channel and the end of the discharge slag outlet adopt a tapered structure, and the taper half angle is 6 - 15 0 , preferably 7.5 0 . Since the viscosity of the molten slag is related to its composition and temperature, sometimes icicle-shaped flowing slag will be formed. A slag breaker 11 is provided in the lower section of the downcomer 12 of the slag outlet to remove slag in a timely manner.

[0053] Operation process:

[0054] The compressed bulk waste raw material is fed into the pyrolysis channel 1 to heat the waste above 400 °C for slow pyrolysis, making it into a relatively loose accumulation. The gradually expanding structure can effectively adapt to the thermal expansion during the waste pyrolysis process;

[0055] The volatiles, steam, tar, etc. (collectively referred to as pyrolysis gas) generated by the waste pyrolysis enter the gasification reaction chamber 3 through the transition section 2 of the square-to-round structure. Oxygen and natural gas (or fuel gas) are ejected from the gasification burners 4 installed on the side wall of the gasification reaction chamber 3 to undergo a reduction reaction with it, cracking the tar and reducing the volatiles into a synthesis gas of CO, H2, and CO2. The temperature of the synthesis gas reaches 1200 °C - 1400 °C through the heat from below and the heat generated by the gasification reaction. At the same time, oxygen and fuel gas are injected into the top-blowing burner 5 at the top of the gasification reaction chamber 3. Preferably, the gas flow rate ejected from the top-blowing burner is controlled to be 10 - 30 of the average synthesis gas flow rate of the cross-section of the gasification reaction chamber, ensuring that the gas temperature leaving the gasification reaction chamber reaches 1200 °C. Intense turbulence and mixing occur in this area for the high-temperature gas, and the residence time is 2 - 5 s, which is also beneficial to reducing the dust carried by the synthesis gas and the carbon content in the dust.

[0056] The high-temperature syngas enters the quench chamber 19 through the connecting channel 15. The first layer of pressure atomized water nozzles 17 arranged along the periphery cools it to below 200 °C, and then it is further cooled to 120 - 180 °C through the second layer of water / gas atomized nozzles 18. The diameter of the water mist ejected by the pressure atomized water nozzles is 1 - 3 mm, and the diameter of the water mist ejected by the water / gas atomized nozzles is 40 - 150 μm. The ash and slag accumulated during the cooling process are cleaned through the dust remover 16 to keep the channel unobstructed. The cooled syngas is subjected to dry dust removal (preferably a bag filter) and then enters the downstream process for use. The dry ash collected by the dry dust removal is sent into the ash / gas lance 20 together with air and sprayed into the molten reaction chamber 6.

[0057] The pyrolysis slag after pyrolysis through the pyrolysis channel 1 falls into the reaction melting chamber 6 and reacts with the oxygen ejected by the melting burner 7 to generate high temperature to melt it. The natural gas or fuel gas ejected by the melting burner 7 at the same time can be used as auxiliary fuel for combustion to ensure that the temperature of the molten slag flowing out of the reaction melting chamber 6 is greater than 1550 °C; in order to make the oxygen react fully with the pyrolysis slag, the oxygen must penetrate into the stockpile layer, so the oxygen flow rate ejected by the central oxygen lance 7.1 is controlled to be ≥200 m / s, and the flow rates of oxygen and fuel ejected by the peripheral nozzles (the peripheral natural gas nozzle 7.2 and the peripheral auxiliary oxygen nozzle 7.3) are 20 - 50 m / s. The nozzles of the melting burner 7 spray downward along the circumferential radial direction and the angle with the horizontal direction is 15 0 ~25 0 Preferably 20 0 The radial angle is 0 0 When the calorific value of the garbage is sufficient, the fuel gas and auxiliary oxygen channels can be closed, and only the central oxygen lance is introduced.

[0058] The molten slag enters the molten pool 9. The oxygen ejected by the burners 8 arranged around the molten pool continues to react with the unreacted carbon-containing substances in the molten slag, and at the same time, natural gas or fuel gas is sprayed in to maintain the temperature of the molten slag not lower than 1550 °C. Due to the change of the garbage composition, the viscosity of the molten slag may be large and block the molten slag outlet, then the emergency nozzle 10 is started. If ice-like flowing slag appears, the slag breaker 11 is started to break the slag ice. Under normal circumstances, the molten slag falls into the slag water cooling pool 14 through the slag discharge port downcomer 12 and is removed from the furnace by the slag skimmer 13.

[0059] The method of the present invention is particularly suitable for the treatment of compressed blocky garbage raw materials, effectively solving the problems existing in the molten gasification of compressed raw materials, such as difficult full reaction with oxygen, difficult control of the temperature out of the gasification reaction chamber, and difficult treatment of residual carbon powder and dust.

Claims

1. A method for producing synthesis gas by oxy-thermal melting and gasification of garbage, characterized in that, The garbage bags compressed into blocks are sent into the pyrolysis channel of the gasifier for pyrolysis. The pyrolysis gas generated by the garbage pyrolysis rises upward and enters the gasification reaction chamber for a reduction reaction to generate high-temperature synthesis gas. The high-temperature synthesis gas enters the quench chamber from the top of the gasification reaction chamber through the connecting channel and is cooled to 120 - 180 °C before leaving the gasifier. The remaining solid substances after the garbage pyrolysis reaction descend into the reaction melting chamber and react with oxygen. The high-temperature gas generated rises and enters the gasification reaction chamber. The liquid slag formed by the high-temperature melting of the solid substances enters the melting pool and continues to react with the unreacted carbon-containing substances in the slag at high temperature. Finally, it descends through the slag discharge port downcomer into the slag pool and then leaves the gasifier. Among them, a plurality of melting burners are evenly arranged in the reaction melting chamber. The nozzle of the melting burner includes a central oxygen injection lance and an outer peripheral nozzle. The central oxygen injection lance sprays oxygen, and the outer peripheral nozzle sprays auxiliary oxygen and fuel. The flow rate of the oxygen sprayed by the central oxygen injection lance is controlled to be ≥200 m / s, and the flow rate of the oxygen and fuel sprayed by the outer peripheral nozzle is 20 - 50 m / s. A top-blown burner vertically downward is arranged at the top of the gasification reaction chamber. The flow rate of the gas sprayed by the top-blown burner is controlled to be 10 - 30 times the average flow rate of the synthesis gas in the cross-section of the gasification reaction chamber.

2. The method for oxygen thermal method of waste melting and gasification to produce syngas according to claim 1, characterized in that, The cooled raw synthesis gas leaving the gasifier is further separated by bag dust removal to obtain cooled synthesis gas and dry ash. After the dry ash is collected, it is sprayed into the reaction melting chamber together with the gas through an ash / gas spray gun.

3. The method for producing syngas by oxygen thermal method for garbage melting and gasification according to claim 1, characterized in that, The high-temperature synthesis gas is first cooled to below 200 °C by the upper pressure atomizing water nozzle in the quench chamber, and then cooled to 120 - 180 °C by the lower water / gas atomizing nozzle.

4. The method for producing syngas by oxy-thermal melting and gasification of garbage according to claim 1, characterized in that, The reaction temperature in the gasification reaction chamber is 1200 °C - 1400 °C, and the reaction residence time of the pyrolysis gas in the gasification reaction chamber is 2 - 5 s.

5. The method for oxygen thermal conversion of waste melting and gasification to produce syngas according to claim 1, characterized in that, The temperature of the molten slag flowing from the melting pool into the slag discharge port is greater than or equal to 1550 °C.

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