Fixed bed gasification system

Abstract

The utility model provides a fixed bed gasification system. The fixed bed gasification system comprises a fixed bed gasification furnace, a washer and an oil washing tower, the fixed bed gasification furnace comprises a carbon-containing raw material inlet, a gasifying agent inlet, a crude product gas outlet and an ash outlet, and the gasifying agent inlet is communicated to a furnace core in the fixed bed gasification furnace; the scrubber comprises a crude product gas inlet, a first scrubbing oil inlet and an oil-gas mixture outlet, and the crude product gas inlet of the scrubber is connected to the crude product gas outlet of the fixed bed gasifier; the oil washing tower comprises an oil-gas mixture inlet, a second washing oil inlet, a gas outlet and a dust-containing oil outlet, and the oil-gas mixture inlet of the oil washing tower is connected to the oil-gas mixture outlet of the washer. The utility model has at least one of the following effects: the structure is simple; product gas dedusting and purifying effects are good; the energy utilization rate is high; the sewage discharge amount is small; sewage is easy to treat; blockage is not easy to occur; the deslagging is simple; the safety performance is good.

Description

Technical Field

[0001] The utility model belongs to the technical field of fixed bed gasification, in particular to a fixed bed gasification system. Background Art

[0002] The fixed bed gasifier is a gasifier that feeds lump raw materials. The lump raw materials in the fixed bed gasifier enter from the top, countercurrently contact and react with the gasifying agent entering from the bottom to generate a crude product gas and remaining unreacted ash. The crude product gas generally flows out from the top of the fixed bed gasifier. Since it has not passed through the high-temperature section at the bottom of the gasifier, the oil, phenol, ammonia and other substances produced by the thermal decomposition of the raw materials remain in the crude product gas. In addition, the crude product gas also carries solid particles such as dust. In industry, water quenching is generally used to wash and cool the crude product gas. The oil, phenol, ammonia and dust in the crude product gas are captured by water. The wastewater formed needs to be de-oiled, phenol recovered, and ammonia recovered step by step before it can meet the requirements of biochemical water treatment. Therefore, the wastewater treatment is difficult and costly. Utility Model Content

[0003] The purpose of the utility model is to provide a fixed bed gasification system, which can gasify carbon-containing raw materials and separate and purify the produced raw product gas, thereby solving at least one of the problems in the prior art and reducing the amount of wastewater generated.

[0004] In order to achieve the purpose of this utility model, the following technical solutions are adopted:

[0005] A fixed bed gasification system comprises a fixed bed gasifier, a scrubber and an oil washing tower which are sequentially connected through pipelines; wherein:

[0006] The fixed bed gasifier comprises a carbon-containing raw material inlet at the top, a gasifying agent inlet at the bottom, a raw product gas outlet at the top and an ash outlet at the bottom, and the gasifying agent inlet is connected to the furnace core in the fixed bed gasifier, and is used to respectively introduce the carbon-containing raw material and the gasifying agent through the carbon-containing raw material inlet and the gasifying agent inlet to generate a chemical reaction, and to discharge the ash from the ash outlet, and to output the raw product gas containing CH from the raw product gas outlet. 4 ,CO,CO 2 , H 2 and water vapor and carries crude product gas with oil, phenol, ammonia and dust;

[0007] The scrubber is provided with a raw product gas inlet, a first wash oil inlet and an oil-gas mixture outlet, and the raw product gas inlet is connected to the raw product gas outlet of the fixed bed gasifier, and is used to input raw product gas from the fixed bed gasifier through the raw product gas inlet, introduce liquid wash oil through the first wash oil inlet to quench and wash the raw product gas to remove part of dust and oil therein, and output the oil-gas mixture through the oil-gas mixture outlet;

[0008] The oil washing tower comprises an oil-gas mixture inlet at the bottom, a second washing oil inlet at the top, a gas outlet at the top and a dust-containing oil outlet at the bottom, and the oil-gas mixture inlet is connected to the oil-gas mixture outlet of the scrubber, and is used to pass the oil-gas mixture from the scrubber through the oil-gas mixture inlet, pass liquid washing oil through the second washing oil inlet to quench and wash the passed oil-gas mixture, and then perform gas-liquid separation, output dust-containing oil containing dust, oil and phenol from the dust-containing oil outlet, and output CH 4 ,CO,CO 2 and H 2 The gas carrying ammonia and water vapor is used as product gas.

[0009] Preferably, the fixed bed gasification system also includes a first oil cooler, and the oil washing tower also includes an oil outlet located at the lower part, the inlet end of the first oil cooler is connected to the oil outlet of the oil washing tower, and the outlet end is connected to the washing oil inlet of the oil washing tower and / or the first washing oil inlet of the scrubber, and is used to cool the oil from the oil washing tower and return it to the oil washing tower and / or the scrubber as liquid washing oil for recycling.

[0010] Preferably, there are multiple oil washing towers and they are connected in sequence; and in two adjacent oil washing towers, the oil-gas mixture inlet of the rear tower is connected to the gas outlet of the front tower, and the dusty oil outlet of the rear tower is provided with a second oil cooler, and the outlet of the second oil cooler is respectively connected to at least one of the second oil washing inlets from the first to the last oil washing tower and the first oil washing inlet of the scrubber, so as to return the material output from the dusty oil outlet in the rear tower for recycling; and / or,

[0011] The interior of the oil washing tower is divided into multiple layers of towers connected in sequence from top to bottom.

[0012] Preferably, the fixed bed gasification system further comprises a first separation unit; the first separation unit comprises a pressure reducing valve, a flash tank, an oil buffer tank, a centrifuge feed pump, a centrifuge, an oil booster pump, a third oil cooler and a flash gas scrubber; wherein,

[0013] The inlet of the pressure reducing valve is connected to the dusty oil outlet of the oil washing tower, and the outlet is connected to the inlets of the flash tank and the oil buffer tank respectively, so as to reduce the pressure of the dusty oil from the oil washing tower and then pass it into the flash tank and the oil buffer tank;

[0014] The flash tank comprises a gas phase outlet at the top and a liquid discharge outlet at the bottom, and is used to perform flash separation on the dust-containing oil introduced, and output flash gas containing non-condensable gas and oil vapor from its gas outlet, and discharge flash liquid containing dust and oil from its liquid discharge outlet;

[0015] The flash gas scrubber comprises a flash gas inlet at the bottom, a fourth wash oil inlet with a wash oil inlet at the top, a non-condensable gas outlet at the top and a liquid phase outlet at one side of the bottom, and its flash gas inlet is connected to the exhaust port of the flash tank, its wash oil inlet is used to introduce liquid wash oil to cool and wash the flash gas from the flash tank, outputs non-condensable gas from its non-condensable gas outlet, and outputs a washing liquid phase containing oil from its liquid phase outlet;

[0016] The inlet of the oil buffer tank is respectively connected to the outlet of the pressure reducing valve, the discharge port of the flash tank and the liquid phase outlet of the flash gas scrubber, and is used to receive the dusty oil from the pressure reducing valve, the flash liquid from the flash tank and the liquid phase from the flash gas scrubber respectively and perform sedimentation separation, obtaining clear oil from the upper overflow and obtaining solid oil from the bottom sedimentation;

[0017] The oil buffer tank, the oil booster pump and the third oil cooler are connected in sequence, and the inlet of the oil booster pump is connected to the clean oil outlet of the oil buffer tank, so as to pump the clean oil from the oil buffer tank to the third oil cooler for cooling and outputting the first product oil;

[0018] The oil buffer tank, the centrifuge feed pump and the centrifuge are connected in sequence, and the inlet of the centrifuge feed pump is connected to the solid oil outlet of the oil buffer tank, which is used to pump the solid oil from the oil buffer tank to the centrifuge for centrifugal dust removal, discharge the second ash, and output the dust removal oil.

[0019] Preferably, the fixed bed gasification system further comprises a second separation unit; the second separation unit comprises a tower top oil cooler, a tower top reflux tank and a sewage pump connected in sequence; wherein,

[0020] The inlet of the tower top oil cooler is connected to the gas outlet of the oil washing tower, and is used to cool the gas from the oil washing tower to condense the oil vapor, water vapor and ammonia vapor therein into condensate to obtain a three-phase mixed material including a gas phase, an oil phase and a water phase; the tower top reflux tank is used to perform three-phase separation on the three-phase mixed material from the tower top oil cooler, discharge sewage, output the second product oil, and output gas as product gas; the sewage pump is used to discharge the sewage from the tower top reflux tank.

[0021] Preferably, a third wash oil inlet is also provided at the upper part of the oil washing tower; the second separation unit also includes a top oil circulation pump, and its inlet end is connected to the second product oil outlet of the top reflux tank, and its outlet end is connected to the third wash oil inlet of the oil washing tower, which is used to circulate part of the second product oil from the top reflux tank to the oil washing tower.

[0022] Preferably, a filter is also provided on the output pipeline of the sewage pump, for filtering the sewage from the sewage pump before outputting it;

[0023] Preferably, the fixed bed gasification system further comprises a sewage heat exchanger and a gas stripping tower;

[0024] The sewage heat exchanger is arranged on the pipeline from the oil washing tower to the tower top oil cooler, and its cold medium inlet is connected to the outlet of the filter, and its cold medium outlet is connected to the cold medium inlet of the first oil cooler, and is used to sequentially use the gas from the oil washing tower and the oil from the oil outlet to heat and heat the material from the filter and output it from the cold medium outlet of the first oil cooler;

[0025] The stripping tower comprises a material inlet at the top, an oxygen inlet and a water vapor inlet located in the middle and arranged from top to bottom, a stripping mixed gas outlet at the top, and a sewage outlet at the bottom; and its material inlet is connected to the cold medium outlet of the first oil cooler, and is used to introduce oxygen and water vapor to strip the cold medium material from the first oil cooler, output the stripping mixed gas from its stripping mixed gas outlet, and discharge sewage from its sewage outlet;

[0026] The stripping mixed gas outlet of the stripping tower is connected to the gasifying agent inlet of the fixed bed gasifier, so as to return the stripping mixed gas from the stripping tower to the fixed bed gasifier.

[0027] Preferably, a cooling water inlet is provided at a lower portion of the fixed bed gasifier below the gasifying agent inlet for replenishing cooling water to cool the ash before discharging it;

[0028] Preferably, the fixed bed gasification system further comprises a third separation unit; the third separation unit comprises a lock hopper and a slag pool connected in sequence;

[0029] The top of the lock hopper is respectively provided with an ash inlet and a drain outlet, and the bottom is provided with an ash outlet, and the ash inlet is connected to the ash outlet of the fixed bed gasifier, so as to collect slag and relieve pressure on the ash water from the fixed bed gasifier, drain water from the drain outlet to the slag pool, and discharge ash from the ash outlet to the slag pool; the ash inlet pipeline, ash outlet pipeline and drain outlet pipeline of the lock hopper are respectively provided with a lock hopper inlet valve, a lock hopper outlet valve and a lock hopper drain valve;

[0030] The slag pool is also provided with an ash outlet and a drain outlet, and the drain outlet is connected to the cooling water inlet of the fixed bed gasifier, so as to separate the ash and water from the lock bucket, output them from the drain outlet and return them to the fixed bed gasifier; a slag pool pump is provided on the pipeline from the slag pool to the fixed bed gasifier.

[0031] Preferably, the fixed bed gasifier is provided with a water-cooled wall; the lower part and the upper part of the shell of the fixed bed gasifier are respectively provided with a boiler water inlet and a boiler water outlet, for introducing boiler water from the boiler water inlet to heat exchange with the water-cooled wall to increase the temperature to form a steam-water mixture and then output from the boiler water outlet;

[0032] Preferably, the fixed bed gasification system further comprises a steam drum, and the steam drum is respectively provided with a steam inlet, a water outlet and a steam outlet, and the steam inlet thereof is connected to the boiler water outlet of the fixed bed gasifier, the water outlet thereof is connected to the boiler water inlet of the fixed bed gasifier, and the steam outlet thereof is connected to the gasifying agent inlet, for passing the steam-water mixture from the fixed bed gasifier through the steam inlet thereof to separate the steam and water, outputting water from the water outlet thereof and circulating it into the shell of the fixed bed gasifier, and outputting water vapor from the steam outlet thereof to the furnace core in the fixed bed gasifier for use as a gasifying agent;

[0033] A boiler water circulation pump is provided on the pipeline from the water outlet of the drum to the boiler water inlet of the fixed bed gasifier, for circulating the water from the drum to the shell of the fixed bed gasifier.

[0034] The beneficial effects of the utility model are:

[0035] The fixed bed gasification system of the utility model has at least one of the following advantages:

[0036] (1) The system structure is simple and easy to operate. It can be applied to the oil-washing dust removal of product gas, and has a good dust removal and purification effect on the product gas. When applied, it can take advantage of the good dust capture effect of oil to achieve efficient dust removal of product gas; multiple oil washing towers or multiple layers of oil washing towers can help achieve efficient dust removal of product gas.

[0037] (2) High energy utilization rate. By setting up a second oil cooler, the sensible heat of the product gas is fully recovered, which improves the energy utilization rate and cools the circulating oil, providing sufficient liquid wash oil for oil washing.

[0038] (3) Low wastewater discharge. The product gas dust removal and purification can be done by oil washing to avoid the introduction of washing water. The wastewater separated by condensation comes only from the water vapor carried by the product gas, which greatly reduces the amount of process wastewater.

[0039] (4) Wastewater is easy to treat and can be directly sent to biochemical treatment. The phenol in the product gas is almost completely dissolved in the oil, and the oil in the process wastewater is also filtered out by the filter, so the phenol and oil content in the wastewater is low; the gas stripping tower is used to further remove ammonia and acid gas in the wastewater, and the treated wastewater can be directly sent to biochemical treatment.

[0040] (5) Simple slag discharge system. The slag discharge system adopts a hydraulic lock bucket slag discharge system with a simple structure. The lock bucket valve is lubricated by water flow, which helps to extend the life of the lock bucket.

[0041] (6) Good safety performance. The gasifier adopts a water-cooled wall + pressure-bearing steel shell structure. The water-cooled wall is heat-insulated but not pressure-bearing, while the shell is pressure-bearing but not temperature-resistant, so it has good safety performance.

[0042] (7) It helps to increase the gasification pressure. The operating pressure of the water-cooled wall is not limited by the gasification pressure, and the gasification pressure can be increased to 10MPaG. By increasing the gasification pressure, not only can the subsequent system investment be reduced, but also the single furnace production capacity can be increased.

[0043] (8) The gasifier can add more temperature measurement points, and the steam-oxygen ratio is easy to control. The gasifier lining adopts a water-cooled wall system. Thermocouples can be installed on the side wall of the water-cooled wall and inserted into the bed layer in the gasifier. The temperature distribution of each layer in the furnace (ash layer, combustion layer, gasification layer, distillation layer, drying layer) can be accurately measured, so as to facilitate the control of the steam-oxygen ratio. The steam-oxygen ratio can be controlled at a lower level, which not only reduces the steam consumption but also reduces the amount of wastewater generated. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a schematic structural diagram of a fixed bed gasification system of the utility model in a first embodiment;

[0045] Figure 2 is a structural schematic diagram of the fixed bed gasification system of the utility model in the second embodiment;

[0046] Figure 3 is a structural schematic diagram of the fixed bed gasification system of the utility model in the third embodiment;

[0047] Figure 4 is a structural schematic diagram of a fixed bed gasification system of the utility model in a fourth embodiment;

[0048] Figure 5 is a structural schematic diagram of a fixed bed gasification system of the utility model in a fifth embodiment;

[0049] Figure 6 is a structural schematic diagram of a fixed bed gasification system of the utility model in a sixth embodiment;

[0050] Figure 7 is a structural schematic diagram of a fixed bed gasification system of the utility model in a seventh embodiment;

[0051] Figure 8 is a structural schematic diagram of the fixed bed gasification system of the utility model in an eighth embodiment;

[0052] Fig. 9It is a schematic structural diagram of the fixed bed gasification system of the utility model in the ninth embodiment. DETAILED DESCRIPTION

[0053] The technical solution and its effects of the utility model are further described below in conjunction with specific implementation methods / examples. The following implementation methods / examples are only used to illustrate the content of the utility model, and the utility model is not limited to the following implementation methods or examples. Simple changes made to the utility model based on the concept of the utility model are within the scope of protection claimed by the utility model.

[0054] The utility model provides a fixed bed gasification system, such as Figure 1 As shown, the fixed bed gasification system comprises a fixed bed gasifier 1, a scrubber 2 and an oil washing tower 3 which are sequentially connected through pipelines; wherein,

[0055] The fixed bed gasifier 1 comprises a carbon-containing raw material inlet 101 at the top, a gasifying agent inlet 102 at the bottom, a raw product gas outlet 103 at the top, and an ash outlet 104 at the bottom, and the gasifying agent inlet 102 is connected to the furnace core in the fixed bed gasifier 1, and is used to respectively introduce the carbon-containing raw material and the gasifying agent through the carbon-containing raw material inlet 101 and the gasifying agent inlet 102 to generate a chemical reaction, and discharge the ash from the ash outlet 104, and output the raw product gas containing CH from the raw product gas outlet 103. 4 ,CO,CO 2 , H 2 and water vapor and carries crude product gas with oil, phenol, ammonia and dust;

[0056] The scrubber 2 is provided with a raw product gas inlet 201, a first wash oil inlet 202 and an oil-gas mixture outlet 203, and its raw product gas inlet 201 is connected to the raw product gas outlet 103 of the fixed bed gasifier 1, and is used to input raw product gas from the fixed bed gasifier 1 through its raw product gas inlet 201, pass liquid wash oil through its first wash oil inlet 202 to quench and wash the raw product gas to remove part of dust and oil therein, and output the oil-gas mixture through its oil-gas mixture outlet 203;

[0057] The oil washing tower 3 comprises an oil-gas mixture inlet 301 at the bottom, a second washing oil inlet 302 at the top, a gas outlet 303 at the top and a dust-containing oil outlet 304 at the bottom, and the oil-gas mixture inlet 301 thereof is connected to the oil-gas mixture outlet 203 of the scrubber 2, and is used to pass the oil-gas mixture from the scrubber 2 through the oil-gas mixture inlet 301 thereof, pass liquid washing oil through the second washing oil inlet 302 thereof to quench and wash the passed oil-gas mixture, and then perform gas-liquid separation, output dust-containing oil containing dust, oil and phenol from the dust-containing oil outlet 304 thereof, and output gas containing CH4 ,CO,CO 2 and H 2 The gas carrying ammonia and water vapor is used as product gas.

[0058] The fixed bed gasification system of the utility model abandons the commonly used water washing method and adopts oil washing dust removal technology, which utilizes the good dust capture effect of oil and helps to achieve efficient dust removal of product gas; avoids the introduction of water washing water, and the sewage separated by condensation only comes from the water vapor carried by the product gas, greatly reducing the amount of process wastewater and the amount of sewage discharged; almost all of the phenol in the product gas can be dissolved in the liquid washing oil and removed.

[0059] Those skilled in the art understand that the carbon-containing raw materials include coal, biomass, and garbage, etc.; the gasifying agent includes at least oxygen, and may further include water vapor and / or carbon dioxide (i.e., the gasifying agent includes any one of the following: oxygen; oxygen and water vapor; oxygen and carbon dioxide; oxygen, water vapor, and carbon dioxide). The chemical reaction between the carbon-containing raw materials and the gasifying agent is a combustion and gasification reaction, and the generated products include CO, H 2 , CO 2 , H 2 O、CH 4 , tar, phenols, ammonia and ash, etc.

[0060] The fixed bed gasification system of the utility model can control the reduction of the fractionation of light oil and heavy oil by controlling the temperature difference between the top and the bottom of the oil washing tower (specifically, the temperature of the liquid washing oil can be increased by increasing the circulation flow of the liquid washing oil, or by reducing the load of the first oil cooler, thereby reducing the temperature difference between the top and the bottom of the oil washing tower), so that the dusty oil at the bottom of the oil washing tower contains some light oil components, and it is not easy to generate asphalt to clog equipment and pipelines.

[0061] In the present invention, the liquid wash oil may be any oil that can be used as wash oil, including oil separated from the crude product gas produced by the present invention, or purchased coal tar, etc.

[0062] Since the oil separated from the crude product gas produced by the utility model can also be used as the liquid wash oil of the scrubber 2 and / or the oil wash tower 3, in order to reduce the amount of liquid wash oil and dust removal costs and improve energy utilization, in one embodiment, as Figure 2As shown, the fixed bed gasification system also includes a first oil cooler 4, and the oil washing tower 3 also includes an oil outlet 305 located at the lower part, the inlet end of the first oil cooler 4 is connected to the oil outlet 305 of the oil washing tower 3, and the outlet end is connected to the washing oil inlet of the oil washing tower 3 and / or the first washing oil inlet 202 of the scrubber 2, and is used for cooling the oil from the oil washing tower 3 and returning it to the oil washing tower 3 and / or the scrubber 2 as liquid washing oil for recycling.

[0063] In order to improve the dust removal effect, in one embodiment, Figure 3 As shown, there are multiple oil washing towers 3 and they are connected in sequence; and in two adjacent oil washing towers 3, the oil-gas mixture inlet 301 of the rear tower is connected to the gas outlet 303 of the front tower, and the dusty oil outlet 304 of the rear tower is provided with a second oil cooler 306, and the outlet of the second oil cooler 306 is respectively connected to the second oil washing inlet 302 of the first oil washing tower 3 to the last oil washing tower 3 and at least one of the first oil washing inlet 202 of the scrubber 2, for returning the material output from the dusty oil outlet 304 in the rear tower for recycling.

[0064] The utility model can fully recover the sensible heat of the raw product gas by arranging the second oil cooler, cool the circulating oil while improving the energy utilization rate, and provide sufficient liquid washing oil for oil washing.

[0065] In order to improve the dust removal effect, in one embodiment, Figure 4 As shown, the interior of the oil washing tower 3 is divided into multiple layers of towers connected in sequence from top to bottom, so that the oil and gas mixture from the washing tower 2 is washed multiple times to improve the dust removal effect.

[0066] During the operation of the fixed bed gasification system of the utility model, slag must be discharged in time to improve the gasification efficiency and heat utilization rate. In order to effectively and timely discharge slag, in one embodiment, Figure 5 As shown, the fixed bed gasification system further includes a first separation unit; the first separation unit includes a pressure reducing valve 5, a flash tank 6, an oil buffer tank 7, a centrifuge feed pump 8, a centrifuge 9, an oil booster pump 10, a third oil cooler 11 and a flash gas scrubber 12; wherein,

[0067] The inlet of the pressure reducing valve 5 is connected to the dusty oil outlet 304 of the oil washing tower 3, and the outlet is connected to the inlets of the flash tank 6 and the oil buffer tank 7, respectively, for reducing the pressure of the dusty oil from the oil washing tower 3 and then passing it into the flash tank 6 and the oil buffer tank 7;

[0068] The flash tank 6 includes a gas phase outlet at the top and a liquid discharge outlet at the bottom, and is used to perform flash separation on the dust-containing oil introduced, and output flash gas containing non-condensable gas and oil vapor from its gas outlet, and discharge flash liquid containing dust and oil from its liquid discharge outlet;

[0069] The flash gas scrubber 12 comprises a flash gas inlet at the bottom, a fourth wash oil inlet with a wash oil inlet at the top, a non-condensable gas outlet at the top and a liquid phase outlet at one side of the bottom, and its flash gas inlet is connected to the exhaust port of the flash tank 6, its wash oil inlet is used to introduce liquid wash oil to cool and wash the flash gas from the flash tank 6, outputs non-condensable gas from its non-condensable gas outlet, and outputs a washing liquid phase containing oil from its liquid phase outlet;

[0070] The inlet of the oil buffer tank 7 is respectively connected to the outlet of the pressure reducing valve 5, the drain port of the flash tank 6 and the liquid phase outlet of the flash gas scrubber 12, and is used to receive the dusty oil from the pressure reducing valve 5, the flash liquid from the flash tank 6 and the liquid phase from the flash gas scrubber 12 and perform sedimentation separation, obtain clear oil from the upper overflow, and obtain solid oil from the bottom sedimentation;

[0071] The oil buffer tank 7, the oil booster pump 10 and the third oil cooler 11 are connected in sequence, and the inlet of the oil booster pump 10 is connected to the clean oil outlet of the oil buffer tank 7, so as to pump the clean oil from the oil buffer tank 7 to the third oil cooler 11 for cooling and outputting the first product oil;

[0072] The oil buffer tank 7, the centrifuge feed pump 8 and the centrifuge 9 are connected in sequence, and the inlet of the centrifuge feed pump 8 is connected to the solid oil outlet of the oil buffer tank 7, so as to pump the solid oil from the oil buffer tank 7 to the centrifuge 9 for centrifugal dust removal, discharge the second ash, and output the dust removal oil.

[0073] The utility model reduces the pressure of dust-containing oil first, separates the ash residue to obtain light oil substantially free of dust, and then cools the substantially dust-free clean oil to output the first product oil. At this time, the clean oil is not easy to be blocked in the pipeline.

[0074] In one embodiment, Figure 5 As shown, the first separation unit also includes a first return pipeline 111, and a first end of which is connected to the outlet of the third oil cooler 11, and a second end of which is connected to the fourth wash oil inlet of the flash gas scrubber 12, which is used to return the first product oil from the third oil cooler 11 to the flash gas scrubber 12, thereby improving the utilization rate of the oil produced during gasification.

[0075] In one embodiment, Figure 5As shown, the first separation unit also includes a second return pipeline 91, and a first end of the second return pipeline 91 is connected to the dust oil outlet of the centrifuge 9, and a second end of the second return pipeline 91 is connected to the inlet of the oil buffer tank 7, for returning the dust oil from the centrifuge 9 to the oil buffer tank 7 for circulation treatment.

[0076] In one embodiment, Figure 5 As shown, the first separation unit also includes a third return pipeline 81, and a first end of the third return pipeline 81 is connected to the outlet of the centrifuge feed pump 8, and a second end of the third return pipeline 81 is connected to the inlet of the oil buffer tank 7, for returning the solid oil from the centrifuge feed pump 8 to the oil buffer tank 7 for circulating treatment thereof.

[0077] In one embodiment, Figure 6 As shown, the fixed bed gasification system further includes a second separation unit; the second separation unit includes a tower top oil cooler 13, a tower top reflux tank 14 and a sewage pump 16 connected in sequence; wherein,

[0078] The inlet of the tower top oil cooler 13 is connected to the gas outlet 303 of the oil washing tower 3, and is used to cool the gas from the oil washing tower 3 to condense the oil vapor, water vapor and ammonia vapor therein into condensate to obtain a three-phase mixed material including a gas phase, an oil phase and a water phase; the tower top reflux tank 14 is used to perform three-phase separation on the three-phase mixed material from the tower top oil cooler 13, discharge sewage, and output the second product oil and product gas; the sewage pump 16 is used to discharge the sewage from the tower top reflux tank 14.

[0079] The utility model provides a tower top oil cooler 13 at the gas outlet 303 of the oil washing tower 3, thereby cooling the gas from the oil washing tower 3 to condense the oil vapor, water vapor and ammonia vapor therein into condensate and remove them; by providing a tower top reflux tank 14 and a sewage pump 16, the material output after the condensate is removed is separated into three phases, the sewage is discharged, the second product oil is output, and the gas is output as the product gas.

[0080] In one embodiment, a third wash oil inlet is further provided at the top of the oil washing tower 3; the second separation unit also includes a top oil circulation pump 15, and its inlet end is connected to the second product oil outlet of the top reflux tank 14, and its outlet end is connected to the third wash oil inlet of the oil washing tower 3, which is used to circulate part of the second product oil from the top reflux tank 14 to the oil washing tower 3, thereby providing liquid wash oil to the oil washing tower and improving the utilization rate of the oil produced during gasification.

[0081] In one embodiment, in the oil washing tower 3 , the third washing oil inlet is located above the second washing oil inlet 302 , so as to facilitate receiving the second product oil from the tower top reflux tank 14 .

[0082] In one embodiment, Figure 7 As shown, a filter 17 is also provided on the output pipeline of the sewage pump 16 for filtering the sewage from the sewage pump 16 before outputting it.

[0083] In the utility model, the oil in the process wastewater can be removed by setting the filter 17. At the same time, since phenol is also mostly dissolved in oil, the wastewater discharged after filtering by the filter 17 has low phenol and oil contents, which helps to reduce the difficulty and cost of treatment.

[0084] In one embodiment, the fixed bed gasification system further includes a sewage heat exchanger 18 and a gas stripping tower 19;

[0085] The sewage heat exchanger 18 is arranged on the pipeline from the oil washing tower 3 to the tower top oil cooler 13, and its cold medium inlet is connected to the outlet of the filter 17, and its cold medium outlet is connected to the cold medium inlet of the first oil cooler 4, and is used to sequentially use the gas from the oil washing tower 3 and the oil from the oil outlet 305 to heat the material from the filter 17 and heat it up, and output it from the cold medium outlet of the first oil cooler 4;

[0086] The stripping tower 19 includes a material inlet at the top, an oxygen inlet and a water vapor inlet located in the middle and arranged from top to bottom, a stripping mixed gas outlet at the top, and a sewage outlet at the bottom; and its material inlet is connected to the cold medium outlet of the first oil cooler 4, for introducing oxygen and water vapor to strip the cold medium material from the first oil cooler 4, outputting the stripping mixed gas from its stripping mixed gas outlet, and discharging sewage from its sewage outlet;

[0087] The stripping mixed gas outlet of the stripping tower 19 is connected to the gasifying agent inlet 102 of the fixed bed gasifier 1 , so as to return the stripping mixed gas from the stripping tower 19 to the fixed bed gasifier 1 .

[0088] In the utility model, by setting up a gas stripping tower, ammonia and acid gas in sewage can be further removed, thereby further reducing difficult-to-treat substances in sewage. The sewage discharged after treatment by the gas stripping tower can be directly subjected to biochemical treatment, which helps to reduce the difficulty and cost of treatment.

[0089] In one embodiment, Figure 8 As shown, a cooling water inlet is also provided at the lower part of the fixed bed gasifier 1 below the gasifying agent inlet 102 for replenishing cooling water to cool the ash before discharging it.

[0090] In one embodiment, Figure 8As shown, the fixed bed gasification system further includes a third separation unit; the third separation unit includes a lock bucket 20 and a slag pool 21 connected in sequence;

[0091] The top of the lock hopper 20 is respectively provided with an ash inlet and a drain outlet, and the bottom is provided with an ash outlet, and the ash inlet is connected to the ash outlet 104 of the fixed bed gasifier 1, for collecting slag and relieving pressure on the ash water from the fixed bed gasifier 1, draining water from the drain outlet to the slag pool 21, and discharging ash from the ash outlet to the slag pool 21; the ash inlet pipeline, ash outlet pipeline and drain outlet pipeline of the lock hopper 20 are respectively provided with a lock hopper inlet valve, a lock hopper outlet valve and a lock hopper drain valve;

[0092] The slag pool 21 is also provided with an ash outlet and a drain outlet, and its drain outlet is connected to the cooling water inlet of the fixed bed gasifier 1, so as to separate the ash and water from the lock bucket 20, output them from the drain outlet and return them to the fixed bed gasifier 1; a slag pool pump is provided on the pipeline from the slag pool 21 to the fixed bed gasifier 1.

[0093] The utility model adopts a hydraulic lock bucket to discharge slag, has a simple structure, and the lock bucket valve is lubricated by water flow, which helps to prolong the life of the lock bucket.

[0094] In one embodiment, Fig. 9 As shown, the fixed bed gasifier 1 is provided with a water-cooled wall; the lower and upper parts of the shell of the fixed bed gasifier 1 are respectively provided with a boiler water inlet and a boiler water outlet, which are used to introduce boiler water from the boiler water inlet to heat exchange with the water-cooled wall to increase the temperature to form a steam-water mixture and then output it from the boiler water outlet.

[0095] In the utility model, the operating pressure of the water-cooled wall is not limited by the gasification pressure, and the gasification pressure can be increased to 10MPaG. By increasing the gasification pressure, not only can the subsequent system investment be reduced, but also the single furnace production capacity can be improved. At the same time, since the gasifier lining adopts a water-cooled wall, a thermocouple can be installed on the side wall of the water-cooled wall and inserted into the bed layer in the gasifier, and the temperature distribution of each layer in the furnace (ash layer, combustion layer, gasification layer, distillation layer, drying layer) can be accurately measured, so as to facilitate the control of the steam-oxygen ratio, and control the steam-oxygen ratio at a lower level, which not only reduces the steam consumption but also reduces the amount of wastewater generated.

[0096] In one embodiment, the water-cooled wall is a pressure-bearing steel shell structure.

[0097] The fixed bed gasification system of the utility model has good safety performance. The gasification furnace adopts a water-cooled wall + pressure-bearing steel shell structure, the water-cooled wall is heat-insulated but not pressure-bearing, and the shell is pressure-bearing but not temperature-resistant, so it has good safety performance.

[0098] In one embodiment, Fig. 9As shown, the fixed bed gasification system further comprises a steam drum 22, and the steam drum 22 is respectively provided with a steam inlet, a water outlet and a steam outlet, and the steam inlet thereof is connected to the boiler water outlet of the fixed bed gasifier 1, the water outlet thereof is connected to the boiler water inlet of the fixed bed gasifier 1, and the steam outlet thereof is connected to the gasifying agent inlet 102, for introducing the steam-water mixture from the fixed bed gasifier 1 from the steam inlet thereof to separate the steam and water, outputting water from the water outlet thereof and circulating it into the shell of the fixed bed gasifier 1, and outputting water vapor from the steam outlet thereof to the furnace core in the fixed bed gasifier 1 to be used as a gasifying agent;

[0099] A boiler water circulation pump 23 is provided on the pipeline from the water outlet of the steam drum 22 to the boiler water inlet of the fixed bed gasifier 1 , for circulating the water from the steam drum 22 to the shell of the fixed bed gasifier 1 .

[0100] The fixed bed gasification system of the utility model can gasify carbon-containing raw materials and effectively separate and purify the produced raw product gas, thereby reducing the amount of waste water generated and the difficulty of treatment.

[0101] Fixed bed gasification can be performed using the aforementioned fixed bed gasification system.

[0102] In one embodiment, Figure 1 As shown, the fixed bed gasification method comprises:

[0103] (1) The carbon-containing raw material and the gasifying agent are introduced into the fixed bed gasifier 1 to generate a chemical reaction, and ash is discharged, and the output includes CH 4 ,CO,CO 2 , H 2 and water vapor and carries crude product gas with oil, phenol, ammonia and dust;

[0104] (2) passing the obtained raw product gas into the scrubber 2 to be quenched and scrubbed by the liquid scrubbing oil to remove part of the dust and oil therein, and outputting the oil-gas mixture;

[0105] (3) The obtained oil-gas mixture is passed into the oil washing tower 3, where it is quenched and washed with the liquid washing oil, and then the gas-liquid separation is performed to output the dust-containing oil containing dust and phenol and the dust-containing oil containing CH 4 ,CO,CO 2 and H 2 The gas carrying ammonia and water vapor is used as product gas.

[0106] In one embodiment, in step (1), the reaction conditions include: the reaction pressure is 0.1-10 MPaG, such as 2 MPaG, 4 MPaG, 6.5 MPaG and 8 MPaG; the reaction temperature is 800-1100°C, such as 900°C and 1000°C.

[0107] In the present invention, the reaction temperature in step (1) is lower than the ash melting point of the carbon-containing raw material.

[0108] In one embodiment, the temperature of the raw product gas obtained in step (1) is 200-600°C, such as 300°C, 400°C and 500°C.

[0109] In one embodiment, in step (2), the temperature of the liquid wash oil introduced is 100-500°C, such as 200°C, 300°C and 400°C.

[0110] In one embodiment, in step (3), the temperature of the liquid wash oil introduced is 100-500°C, such as 200°C, 300°C and 400°C.

[0111] In one embodiment, Figure 2 As shown, in step (3), the oil washing tower 3 also outputs oil containing dust from its oil outlet 305, and the fixed bed gasification method also includes cooling the oil output from its oil outlet 305 and returning it to the oil washing tower 3 and / or the scrubber 2 as liquid washing oil for recycling.

[0112] In one embodiment, Figure 3 As shown, in step (3), the obtained oil-gas mixture is passed into at least two oil washing towers 3 connected in series, and the liquid washing oil is used to perform at least two quench washings, and the dusty oil containing dust and phenol is discharged from the bottom of the first oil washing tower 3, and the dusty oil containing CH4 is discharged from the top of the last oil washing tower 3. 4 , CO and H 2 Preferably, the bottom materials of the second oil washing tower 3 and the oil washing towers 3 thereafter are respectively returned to any one or more of the first to the last oil washing tower 3 and the scrubber 2 to be recycled as their liquid washing oil.

[0113] In one embodiment, Figure 4 As shown, in step (3), the obtained oil-gas mixture is passed into the oil washing tower 3 arranged in a multi-layer tower for multiple washings, and the dusty oil containing dust and phenol is discharged from the bottom, and the dusty oil containing CH 4 ,CO,CO 2 and H 2 The gas carrying ammonia and water vapor is used as product gas.

[0114] In one embodiment, in step (3), the top temperature and / or bottom temperature of the oil washing tower 3 is 100-500°C (e.g., 200°C, 300°C, and 400°C), and the temperature difference between the top and the bottom is less than 50°C (e.g., 40°C, 30°C, 20°C, and 10°C).

[0115] In one embodiment, Figure 5 As shown, the fixed bed gasification method further includes step (4), that is, passing the dusty oil discharged from step (3) into the first separation unit for separation treatment. In one embodiment, the step (4) is to pass the dusty oil discharged from step (3) into the first separation unit and decompress it (preferably to normal pressure), and then perform flash separation to output flash gas containing non-condensable gas and oil vapor, and flash liquid containing dust and oil, and then wash the output flash gas and discharge the non-condensable gas to the flare pipeline, and output the washing liquid phase; the other part and any one or more of the flash liquid and the washing liquid phase are sent to the oil buffer tank 7 for buffering and sedimentation separation, and the clear oil obtained from the upper overflow is cooled and partly output as the first product oil and partly as liquid washing oil of the flash gas, and part of the solid oil obtained from the bottom sedimentation is directly returned to the oil buffer tank 7 to avoid clogging of the centrifugal equipment during offline maintenance, and the other part is returned to the oil buffer tank 7 after centrifugal separation and dust removal and discharged ash residue.

[0116] In one embodiment, Figure 6 As shown, the fixed bed gasification method further includes step (5), that is, passing the product gas output from step (3) into a second separation unit for separation treatment. In one embodiment, the step (5) is that the product gas output from step (3) is passed into the second separation unit and cooled (preferably cooled to 0-60°C), and the oil vapor, water vapor and ammonia vapor therein are condensed into condensate to obtain a three-phase mixture material including a gas phase, an oil phase and a water phase; then the three-phase mixture obtained after cooling is sent to the top reflux tank 14 for three-phase separation, the separated wastewater is discharged through the wastewater pump 16, and the separated oil is partially output as the second product oil, and partially returned to the oil washing tower 3 through the top circulation pump 15, and the separated output contains CO, H 2 , CO 2 , CH 4 product gas.

[0117] In one embodiment, Figure 7 As shown, step (5) also includes filtering and heating the sewage discharged by the sewage pump 16, and then sending it to the stripping tower 19 for stripping, discharging the sewage, and outputting the stripping mixed gas.

[0118] In the utility model, oxygen and water vapor are also sent to the stripping tower, and the acid gas and ammonia in the filtered and heated sewage are stripped out through oxygen and water vapor in the stripping tower, and part of the waste water is vaporized into water vapor.

[0119] In a preferred embodiment, Figure 7 As shown, in step (5), the sewage discharged by the sewage pump 16 is filtered and heated by sending it to the sewage heat exchanger 18 for heat exchange and heating with the product gas output in step (3), and then sent to the first oil cooler 4 for heat exchange and heating with the oil from the oil outlet 305 in the oil washing tower 3.

[0120] In a preferred embodiment, Figure 7 As shown, the product gas separated in step (5) is returned to the fixed bed gasifier 1 through the gasifying agent inlet 102 of the fixed bed gasifier 1 to be used as a gasifying agent.

[0121] In one embodiment, Figure 8 As shown, in step (1), the fixed bed gasifier 1 is supplemented with cooling water through its cooling water inlet to cool the ash before discharging it and then discharging it with water, namely, ash water.

[0122] In a preferred embodiment, Figure 8 As shown, the fixed bed gasification method further includes step (6), that is, passing the ash water discharged from step (1) into a third separation unit for separation treatment. In one embodiment, step (6) is to pass the ash water discharged from step (1) into the third separation unit for slag collection and pressure relief (pressure relief to normal pressure) through the lock bucket 20, and discharge water and ash from its water outlet and ash outlet respectively into the slag pool 21 for slag-water separation, discharge ash, and output water.

[0123] In a preferred embodiment, Figure 8 As shown, the water outputted in step (6) is returned to the fixed bed gasifier 1 through the cooling water inlet of the fixed bed gasifier 1 for water replenishment, and the preferred water replenishment flow rate is 10 to 50 m 3 / h, for example 20m 3 / h、30m 3 / h and 40m 3 / h.

[0124] In one embodiment, Fig. 9 As shown, the fixed bed gasification method further includes step (7), i.e., boiler water is introduced into the shell of the fixed bed gasifier 1 from the boiler water inlet to heat exchange with its water-cooled wall to increase the temperature to form a steam-water mixture, and then discharged from the boiler water outlet, thereby cooling the water-cooled wall.

[0125] In one embodiment, Fig. 9 As shown, the fixed bed gasification method further includes step (8), wherein the step (8) is to pass the steam-water mixture output from step (7) into the steam drum 22 for steam-water separation, output water from its water outlet and circulate it into the shell of the fixed bed gasifier 1, and output water vapor from its steam outlet to the furnace core in the fixed bed gasifier 1 for use as a gasifying agent.

[0126] Those skilled in the art will appreciate that the various devices used in the fixed bed gasification system of the utility model are all commonly used devices in the field, and corresponding lifting pumps or booster pumps may be provided on the pipeline to facilitate the transportation of materials in the pipeline, valves may be provided to control the transportation of materials in the pipeline, and corresponding buffer tanks may also be provided for the corresponding materials to facilitate the buffering and storage of the corresponding materials, which will not be described in detail.

[0127] The fixed bed gasification system of the utility model has at least one of the following effects: good dust removal and purification effect on product gas; high energy utilization rate; small sewage discharge; sewage can be directly sent to biochemical treatment, which is easy to handle; simple slag discharge; good safety performance; high gasification pressure, which can reduce subsequent system investment and improve the production capacity of a single furnace; the gasification furnace can add more temperature measuring points, and the steam-oxygen ratio is convenient to control, and the steam-oxygen ratio can be controlled at a lower level, which reduces both the steam consumption and the wastewater generation.

[0128] The raw materials used in the following examples and comparative examples of the present invention are as follows:

[0129] The carbon-containing raw material is bituminous coal, and its specific information is shown in Table 1;

[0130] Liquid wash oil is the second product oil produced by the company, and its specific information is shown in Table 2;

[0131] Table 1 Analysis results of bituminous coal

[0132]

[0133]

[0134] Table 2 Physical properties of liquid wash oil

[0135] project unit nature Density(20℃) <![CDATA[g / cm 3 ]]> 0.98～1.06 Viscosity (60℃) <![CDATA[mm 2 / s]]> 50

[0136] The determination / calculation methods of relevant parameters are as follows:

[0137] The components of sewage were determined by Nessler's reagent spectrophotometry according to HJ535-2009 - Determination of ammonia nitrogen in water quality. The phenol content in sewage was determined by direct bromination method. The oil content in sewage was determined by infrared photometry according to HJ 637-2012 - Determination of petroleum, animal and vegetable oils in water quality. The COD value in sewage was determined by rapid digestion spectrophotometry according to HJ / T399-2007 - Determination of chemical oxygen demand in water quality.

[0138] Example 1 (S1)

[0139] Use Figure 1 The fixed bed gasification system shown in the figure performs fixed bed gasification on the carbon-containing raw material, and the processing capacity of the carbon-containing raw material in a single furnace is 650t / d, and includes the following steps:

[0140] (1) The carbon-containing raw material and the gasifying agent are introduced into the fixed bed gasifier 1 to generate a chemical reaction, and ash is discharged, and the output includes CH 4 ,CO,CO 2 , H 2 The raw product gas containing oil, phenol, ammonia and dust is a mixture of water vapor and carbon-containing raw material, with an inflow rate of 27.2 t / h; the gasifying agent is oxygen and water vapor, with inflow rates of 6796 Nm 3 / h and 23.7t / h; the reaction conditions include: operating temperature of 1100°C and operating pressure of 3.5MPaG;

[0141] (2) The obtained raw product gas is passed into the scrubber 2 and quenched and scrubbed with the liquid wash oil to remove part of the dust and oil therein, and the oil-gas mixture is output; wherein the liquid wash oil is the second product oil produced by the self-produced product, the temperature of which is 260°C and the flow rate of which is 20m 3 / h;

[0142] (3) The obtained oil-gas mixture is passed into the oil washing tower 3, where it is quenched and washed with the liquid washing oil, and then the gas-liquid separation is performed to output the dust-containing oil containing dust and phenol and the dust-containing oil containing CH 4 ,CO,CO 2 and H 2 The gas carrying ammonia and water vapor is used as the product gas; the liquid wash oil introduced is the second product oil produced by the company, with a temperature of 260°C and an inlet flow rate of 150m 3 / h.

[0143] Embodiment 2 (S2)

[0144] Use Figure 2 The fixed bed gasification system shown performs fixed bed gasification on the carbon-containing raw material, wherein the fixed bed gasification method has the following differences compared with Example 1:

[0145] In step (3), the oil washing tower 3 outputs oil from its oil outlet 305, and the oil output from its oil outlet 305 is cooled to 260° C. by the first oil cooler 4, and then returned to the oil washing tower 3 and the scrubber 2 as liquid wash oil for recycling.

[0146] Embodiment 3 (S3)

[0147] Use Figure 3 The fixed bed gasification system shown performs fixed bed gasification on the carbon-containing raw material, wherein the fixed bed gasification method has the following differences compared with Example 1:

[0148] In step (3), the obtained oil-gas mixture is passed into two oil washing towers 3 connected in series, and the liquid washing oil is used to perform a second quench washing, and the dusty oil containing dust and phenol is discharged from the bottom of the first oil washing tower 3, and the dusty oil containing CH4 is discharged from the top of the second oil washing tower 3. 4 ,CO,CO 2 and H 2 The gas carrying ammonia and water vapor is used as the product gas; and the bottom material of the second oil washing tower 3 is respectively returned to the first oil washing tower 3, the second oil washing tower 3 and the scrubber 2 to be recycled as its liquid washing oil.

[0149] Embodiment 4 (S4)

[0150] Use Figure 4 The fixed bed gasification system shown performs fixed bed gasification on the carbon-containing raw material, wherein the fixed bed gasification method has the following differences compared with Example 1:

[0151] In step (3), the obtained oil-gas mixture is passed into the oil washing tower 3 arranged in a multi-layer tower for multiple washings, and the dusty oil containing dust and phenol is discharged from the bottom, and the dusty oil containing CH 4 ,CO,CO 2 and H 2 The gas carrying ammonia and water vapor is used as product gas.

[0152] Embodiment 5 (S5)

[0153] Use Figure 5 The fixed bed gasification system shown performs fixed bed gasification on the carbon-containing raw material, wherein the fixed bed gasification method has the following differences compared with Example 1:

[0154] The method further comprises step (4), i.e., passing the dusty oil discharged from step (3) into a first separation unit for separation treatment, which is specifically as follows: passing the dusty oil discharged from step (3) into the first separation unit and reducing the pressure to normal pressure through a pressure reducing valve 5, a part of which is sent to a flash tank 6 for flash separation, and flash gas containing non-condensable gas and oil vapor and flash liquid containing dust and oil are output; the output flash gas is then sent to a flash gas scrubber 12 for washing, and the non-condensable gas is discharged to the flare pipeline, and the washing liquid phase is output; the other part is sent to the flash gas scrubber 12 together with the flash liquid and the washing liquid phase. The oil buffer tank 7 performs buffering and sedimentation separation, the clear oil overflowed from the top is lifted and pumped by the oil booster pump 10 to the third oil cooler 11 for cooling, and then part of it is output as the first product oil and part of it is returned to the flash gas scrubber 12 as liquid washing oil for flash gas, the solid oil obtained from the bottom sedimentation is lifted and pumped by the centrifuge feed pump 8, part of it is directly returned to the oil buffer tank 7 to avoid clogging of the centrifugal equipment during offline maintenance, and the other part is sent to the centrifuge 9 for centrifugal separation and dust removal, and then returned to the oil buffer tank 7 to discharge ash.

[0155] Embodiment 6 (S6)

[0156] Use Figure 6 The fixed bed gasification system shown performs fixed bed gasification on the carbon-containing raw material, wherein the fixed bed gasification method has the following differences compared with Example 5:

[0157] The method further comprises step (5), i.e., passing the product gas outputted from step (3) into a second separation unit for separation treatment, which is specifically as follows: the product gas outputted from step (3) is passed into the second separation unit and cooled to 40° C. by the tower top oil cooler 13, and the oil vapor, water vapor and ammonia vapor therein are condensed into condensate to obtain a three-phase mixture material comprising a gas phase, an oil phase and a water phase; and the three-phase mixture material obtained after cooling is sent to the tower top reflux tank 14 for three-phase separation, and the separated wastewater is discharged through the wastewater pump 16, and part of the separated oil is output as the second product oil, and part is returned to the oil washing tower 3 through the tower top circulation pump 15, and the separated product containing CO, H 2 , CO 2 , CH 4 product gas.

[0158] Embodiment 7 (S7)

[0159] Use Figure 7 The fixed bed gasification system shown performs fixed bed gasification on the carbon-containing raw material, wherein the fixed bed gasification method has the following differences compared with Example 6:

[0160] In step (5), before the product gas outputted from step (3) is passed into the tower top oil cooler 13, it is first passed into the sewage heat exchanger 18 for cooling; step (5) also includes sending the sewage discharged from the sewage pump 16 to the filter 17 for filtration and oil removal, and then sending it to the sewage heat exchanger 18 and the first oil cooler 4 in sequence to exchange heat with the product gas outputted from step (3) for heating, and then sending it to the stripping tower 19 for stripping (at the same time, oxygen and water vapor are introduced into the stripping tower 19), discharging the sewage, outputting the stripping mixed gas and returning it to the fixed bed gasifier 1 from the gasifying agent inlet 102 of the fixed bed gasifier 1 for use as a gasifying agent.

[0161] Embodiment 8 (S8)

[0162] Use Figure 8 The fixed bed gasification system shown performs fixed bed gasification on the carbon-containing raw material, wherein the fixed bed gasification method has the following differences compared with Example 7:

[0163] The method further comprises step (6), i.e., passing the ash water discharged from step (1) into a third separation unit for separation treatment, which is specifically as follows: passing the ash water discharged from step (1) into the third separation unit and passing through the lock bucket 20 for slag collection and pressure relief (pressure relief to normal pressure), and discharging water and ash from its water outlet and ash outlet into the slag pool 21 for slag-water separation, discharging ash, and outputting water which is lifted by a slag pool pump and then returned to the fixed bed gasifier 1 from the cooling water inlet of the fixed bed gasifier 1 for water replenishment.

[0164] Embodiment 9 (S9)

[0165] Use Fig. 9 The fixed bed gasification system shown performs fixed bed gasification on the carbon-containing raw material, wherein the fixed bed gasification method has the following differences compared with Example 7:

[0166] The step further includes step (7), i.e., passing boiler water from the boiler water inlet into the shell of the fixed bed gasifier 1 to heat exchange with the water-cooled wall to increase the temperature to form a steam-water mixture, which is then output from the boiler water outlet, thereby cooling the water-cooled wall;

[0167] The method further comprises step (8), i.e., passing the steam-water mixture outputted from step (7) into the steam drum 22 for steam-water separation, outputting water from the water outlet thereof and circulating it from the boiler water inlet to the shell of the fixed bed gasifier 1, and outputting water vapor from the steam outlet thereof and circulating it from the gasifying agent inlet 102 to the furnace core in the fixed bed gasifier 1 for use as a gasifying agent.

[0168] result:

[0169] An analysis of Example 1-5 (S1-5) revealed that there was no wastewater discharge, that is, the wastewater discharge volume was 0, but the product gas obtained contained oil and ammonia, which required further treatment.

[0170] The product gas obtained in Example 6-9 (S6-9) and the product gas obtained by the traditional method of water quenching and washing were used in the subsequent conversion section, and the catalyst service life was measured. The measurement results are shown in Table 3 (the dust content in the product gas will affect the service life of the catalyst in the subsequent conversion section, and the two are inversely proportional).

[0171] Table 3 The service life of the catalyst when the obtained product gas is used in the subsequent conversion process

[0172]

[0173] According to Table 3, in the embodiment of the utility model, the service life of the catalyst when the obtained product gas is used in the subsequent conversion stage is as high as 2 years, and correspondingly, it can be known that its dust content is small. Compared with the traditional method of using water quenching and washing, the service life of the catalyst when the obtained product gas is used in the subsequent conversion stage is only 1.5 years, and correspondingly, it can be known that its dust content is large. The quality of the product gas obtained in the embodiment of the utility model is effectively improved.

[0174] The wastewater discharged from Example 6-9 (S6-9) was analyzed, and the analysis results are shown in Table 4.

[0175] Table 4 Analysis results of discharged sewage

[0176]

[0177] Note: The wastewater discharge in Table 4 is calculated based on the processing capacity of a single furnace of 650t / d of carbon-containing raw materials.

[0178] According to Table 2, in Example 6 of the present invention, the sewage discharge volume is 14.6 t / h, and since the oil and ammonia in the product gas are condensed into condensate and discharged with the sewage, the oil and ammonia content in the discharged sewage is high and the COD value is large; compared with the traditional method of using water quenching and washing, the sewage discharge volume is as high as 26 t / h, which greatly reduces the sewage discharge volume;

[0179] In Examples 7-9 of the present invention, the discharge volume of the discharged sewage is as low as 2t / h, and since the discharged sewage in Example 6 is further treated, the ammonia content in the discharged sewage is as low as 200mg / L, the phenol content is as low as 600mg / L, the oil content is as low as 10mg / L, and the COD is as low as 800mg / L, so it can be directly sent to biochemical treatment, and the treatment difficulty is small; compared with the traditional method of using water quenching washing, the discharge volume of the discharged sewage is as high as 26t / h, and the ammonia content of the discharged sewage in the prior art is as high as 4000-9000mg / L, the phenol content is as high as 6000-10000mg / L, the oil content is as high as 300-600mg / L, and the COD is as high as 3000-5000mg / L, which is difficult to treat, the discharge volume of the discharged sewage in Examples 7-9 of the present invention is greatly reduced, and the contents of ammonia, phenols, oil and COD in the discharged sewage are all greatly reduced, and the treatment difficulty is also greatly reduced.

[0180] According to Examples 1-9, compared with the traditional method of using water quenching and washing, the fixed bed gasification system and the fixed bed gasification method of the utility model are simple and easy to operate, and have at least one of the following effects: the obtained product gas has low dust content and good dust removal and purification effect; the amount of sewage discharged is small; the content of difficult-to-treat components in the discharged sewage is small, and the discharged sewage can be directly sent to biochemical treatment, which is easy to treat.

Claims

1. A fixed bed gasification system, characterized in that: The fixed bed gasification system comprises a fixed bed gasification furnace (1), a scrubber (2) and an oil washing tower (3) which are sequentially connected via pipelines; wherein: The fixed bed gasifier (1) comprises a carbon-containing raw material inlet (101) at the top, a gasifying agent inlet (102) at the bottom, a raw product gas outlet (103) at the top and an ash outlet (104) at the bottom, and the gasifying agent inlet (102) is connected to the furnace core in the fixed bed gasifier (1), and is used to respectively introduce the carbon-containing raw material and the gasifying agent through the carbon-containing raw material inlet (101) and the gasifying agent inlet (102) to generate a chemical reaction, discharge the ash from the ash outlet (104), and output the raw product gas containing CH4, CO, CO2, H2 and water vapor and carrying oil, phenol, ammonia and dust from the raw product gas outlet (103); The scrubber (2) is provided with a raw product gas inlet (201), a first wash oil inlet (202) and an oil-gas mixture outlet (203), and the raw product gas inlet (201) is connected to the raw product gas outlet (103) of the fixed bed gasifier (1), and is used to input raw product gas from the fixed bed gasifier (1) through the raw product gas inlet (201), to introduce liquid wash oil through the first wash oil inlet (202) to quench and wash the raw product gas to remove part of the dust and oil therein, and to output the oil-gas mixture through the oil-gas mixture outlet (203); The oil washing tower (3) comprises an oil-gas mixture inlet (301) at the bottom, a second washing oil inlet (302) at the top, a gas outlet (303) at the top and a dust-containing oil outlet (304) at the bottom, and its oil-gas mixture inlet (301) is connected to the oil-gas mixture outlet (203) of the scrubber (2), and is used to introduce the oil-gas mixture from the scrubber (2) from its oil-gas mixture inlet (301), introduce liquid washing oil from its second washing oil inlet (302) to quench and wash the introduced oil-gas mixture, and then perform gas-liquid separation, output dust-containing oil containing dust, oil and phenol from its dust-containing oil outlet (304), and output gas containing CH4, CO, CO2 and H2 and carrying ammonia and water vapor as product gas from its gas outlet (303).

2. The fixed bed gasification system according to claim 1, characterized in that: The fixed bed gasification system further comprises a first oil cooler (4), and the oil washing tower (3) further comprises an oil outlet (305) located at the lower part, the inlet end of the first oil cooler (4) is connected to the oil outlet (305) of the oil washing tower (3), and the outlet end is connected to the washing oil inlet of the oil washing tower (3) and / or the first washing oil inlet (202) of the washing device (2), so as to cool the oil from the oil washing tower (3) and return it to the oil washing tower (3) and / or the washing device (2) as liquid washing oil for recycling.

3. The fixed bed gasification system according to claim 1 or 2, characterized in that: There are multiple oil washing towers (3) which are connected in sequence; and in two adjacent oil washing towers (3), the oil-gas mixture inlet (301) of the rear tower is connected to the gas outlet (303) of the front tower, and the dusty oil outlet (304) of the rear tower is provided with a second oil cooler (306), and the outlet of the second oil cooler (306) is respectively connected to the second oil washing inlet (302) of the first oil washing tower (3) to the last oil washing tower (3) and at least one of the first oil washing inlet (202) of the scrubber (2), so as to return the material output from the dusty oil outlet (304) in the rear tower for recycling; and / or, The interior of the oil washing tower (3) is divided into multiple layers of towers connected in sequence from top to bottom.

4. The fixed bed gasification system according to claim 1, characterized in that: The fixed bed gasification system further comprises a first separation unit; the first separation unit comprises a pressure reducing valve (5), a flash tank (6), an oil buffer tank (7), a centrifuge feed pump (8), a centrifuge (9), an oil booster pump (10), a third oil cooler (11) and a flash gas scrubber (12); wherein, The inlet of the pressure reducing valve (5) is connected to the dusty oil outlet (304) of the oil washing tower (3), and the outlet is respectively connected to the inlets of the flash tank (6) and the oil buffer tank (7), so as to reduce the pressure of the dusty oil from the oil washing tower (3) and then pass it into the flash tank (6) and the oil buffer tank (7); The flash tank (6) comprises a gas phase outlet at the top and a liquid discharge outlet at the bottom, and is used for flash separation of the dust-containing oil introduced, and outputting flash gas containing non-condensable gas and oil vapor from its gas outlet, and discharging flash liquid containing dust and oil from its liquid discharge outlet; The flash gas scrubber (12) comprises a flash gas inlet at the bottom, a fourth wash oil inlet with a wash oil inlet at the top, a non-condensable gas outlet at the top and a liquid phase outlet at one side of the bottom, and its flash gas inlet is connected to the exhaust port of the flash tank (6), its wash oil inlet is used to introduce liquid wash oil to cool and wash the flash gas from the flash tank (6), outputs non-condensable gas from its non-condensable gas outlet, and outputs a washing liquid phase containing oil from its liquid phase outlet; The inlet of the oil buffer tank (7) is respectively connected to the outlet of the pressure reducing valve (5), the drain port of the flash tank (6) and the liquid phase outlet of the flash gas scrubber (12), and is used to respectively receive the dust-containing oil from the pressure reducing valve (5), the flash liquid from the flash tank (6) and the liquid phase from the flash gas scrubber (12) and perform sedimentation separation, obtain clear oil from the upper overflow, and obtain solid oil from the bottom sedimentation; The oil buffer tank (7), the oil booster pump (10) and the third oil cooler (11) are connected in sequence, and the inlet of the oil booster pump (10) is connected to the clean oil outlet of the oil buffer tank (7), so as to pump the clean oil from the oil buffer tank (7) to the third oil cooler (11) for cooling and outputting the first product oil; The oil buffer tank (7), the centrifuge feed pump (8) and the centrifuge (9) are connected in sequence, and the inlet of the centrifuge feed pump (8) is connected to the solid oil outlet of the oil buffer tank (7), so as to pump the solid oil from the oil buffer tank (7) to the centrifuge (9) for centrifugal dust removal, discharge the second ash residue, and output the dust removal oil.

5. The fixed bed gasification system according to claim 2, characterized in that: The fixed bed gasification system further comprises a second separation unit; the second separation unit comprises a tower top oil cooler (13), a tower top reflux tank (14) and a sewage pump (16) which are connected in sequence; wherein, The inlet of the tower top oil cooler (13) is connected to the gas outlet (303) of the oil washing tower (3), and is used to cool the gas from the oil washing tower (3) to condense the oil vapor, water vapor and ammonia vapor therein into condensate, thereby obtaining a three-phase mixed material comprising a gas phase, an oil phase and a water phase; the tower top reflux tank (14) is used to perform three-phase separation on the three-phase mixed material from the tower top oil cooler (13), discharge sewage, output the second product oil, and output gas as product gas; the sewage pump (16) is used to discharge sewage from the tower top reflux tank (14).

6. The fixed bed gasification system according to claim 5, characterized in that: The upper part of the oil washing tower (3) is also provided with a third washing oil inlet; the second separation unit further comprises a tower top oil circulation pump (15), the inlet end of which is connected to the second product oil outlet of the tower top reflux tank (14), and the outlet end of which is connected to the third washing oil inlet of the oil washing tower (3), for circulating part of the second product oil from the tower top reflux tank (14) to the oil washing tower (3); The third wash oil inlet is higher than the second wash oil inlet (302).

7. The fixed bed gasification system according to claim 5, characterized in that: The output pipeline of the sewage pump (16) is also provided with a filter (17) for filtering the sewage from the sewage pump (16) before outputting it.

8. The fixed bed gasification system according to claim 7, characterized in that: The fixed bed gasification system further comprises a sewage heat exchanger (18) and a gas stripping tower (19); The sewage heat exchanger (18) is arranged on the pipeline from the oil washing tower (3) to the tower top oil cooler (13), and its cold medium inlet is connected to the outlet of the filter (17), and its cold medium outlet is connected to the cold medium inlet of the first oil cooler (4), and is used to sequentially use the gas from the oil washing tower (3) and the oil from the oil outlet (305) to heat the material from the filter (17) and increase its temperature, and output it from the cold medium outlet of the first oil cooler (4); The stripping tower (19) comprises a material inlet at the top, an oxygen inlet and a water vapor inlet located in the middle and arranged from top to bottom, a stripping mixed gas outlet at the top, and a sewage outlet at the bottom; and its material inlet is connected to the cold medium outlet of the first oil cooler (4), and is used to introduce oxygen and water vapor to strip the cold medium material from the first oil cooler (4), output the stripping mixed gas from its stripping mixed gas outlet, and discharge sewage from its sewage outlet; The stripping mixed gas outlet of the stripping tower (19) is connected to the gasifying agent inlet (102) of the fixed bed gasifier (1) for returning the stripping mixed gas from the stripping tower (19) to the fixed bed gasifier (1).

9. The fixed bed gasification system according to any one of claims 1, 2, 4 and 6-8, characterized in that: A cooling water inlet is also provided at a lower portion of the fixed bed gasifier (1) below the gasifying agent inlet (102) for replenishing cooling water to cool the ash before discharging it; The fixed bed gasification system further comprises a third separation unit; the third separation unit comprises a lock hopper (20) and a slag pool (21) connected in sequence; The top of the lock hopper (20) is respectively provided with an ash inlet and a drain outlet, and the bottom is provided with an ash outlet, and the ash inlet is connected to the ash outlet (104) of the fixed bed gasifier (1) for collecting slag and relieving pressure on ash water from the fixed bed gasifier (1), draining water from the drain outlet to the slag pool (21), and discharging ash from the ash outlet to the slag pool (21); the ash inlet pipeline, ash outlet pipeline and drain outlet pipeline of the lock hopper (20) are respectively provided with a lock hopper inlet valve, a lock hopper outlet valve and a lock hopper drain valve; The slag pool (21) is also provided with an ash outlet and a drain outlet, and the drain outlet is connected to the cooling water inlet of the fixed bed gasifier (1) for separating the ash and water from the lock bucket (20), outputting the ash and water from the drain outlet and returning the ash and water to the fixed bed gasifier (1); a slag pool pump is provided on the pipeline from the slag pool (21) to the fixed bed gasifier (1).

10. The fixed bed gasification system according to claim 9, characterized in that: The fixed bed gasifier (1) is provided with a water-cooled wall; the lower part and the upper part of the shell of the fixed bed gasifier (1) are respectively provided with a boiler water inlet and a boiler water outlet, for introducing boiler water from the boiler water inlet to heat-exchange with the water-cooled wall to increase the temperature to form a steam-water mixture, and then outputting the mixture from the boiler water outlet; The fixed bed gasification system further comprises a steam drum (22), and the steam drum (22) is respectively provided with a steam inlet, a water outlet and a steam outlet, and the steam inlet is connected to the boiler water outlet of the fixed bed gasifier (1), the water outlet is connected to the boiler water inlet of the fixed bed gasifier (1), and the steam outlet is connected to the gasifying agent inlet (102), and is used for passing a steam-water mixture from the fixed bed gasifier (1) through the steam inlet to separate the steam and water, outputting water from the water outlet and circulating it into the shell of the fixed bed gasifier (1), and outputting water vapor from the steam outlet to the furnace core in the fixed bed gasifier (1) to be used as a gasifying agent; A boiler water circulation pump (23) is provided on the pipeline from the water outlet of the steam drum (22) to the boiler water inlet of the fixed bed gasifier (1), and is used to circulate the water from the steam drum (22) to the shell of the fixed bed gasifier (1).

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