Method for heat utilization of oil shale retort ash

Abstract

The application discloses a heat utilization method of oil shale dry distillation ash, which comprises the following steps: the oil shale after screening and washing treatment is firstly introduced into a dry distillation furnace preheating section to preliminarily remove water and generate preheating waste gas; the oil shale after preheating is introduced into a dry distillation furnace dry distillation section to generate hydrocarbon steam and shale ash; the hydrocarbon steam is introduced into an oil gas recovery unit to recover liquid products, gas products and acid water; the shale ash is heat-exchanged with deoxygenated water in an ash cooler to generate steam by utilizing the heat of high-temperature ash; the shale ash further enters an ash humidifier, and after being sprayed by water, the shale ash generates quenching steam and wet shale ash; the preheating waste gas is condensed in a preheating waste gas condenser, and the non-condensed gas is introduced into a subsequent incineration device and then discharged into the atmosphere through a chimney; the heat required by dry distillation is provided by a combustion chamber through heat transfer, fuel and air are combusted in the combustion chamber of the dry distillation furnace, and the generated flue gas is treated and then discharged into the atmosphere through the chimney together with the waste gas, so that the energy consumption of the oil shale dry distillation technology is reduced, and the economic benefit of the oil shale dry distillation technology is improved.

Description

Technical Field

[0001] This invention relates to the field of oil shale, and specifically to a method for utilizing the waste heat from the dry distillation of oil shale. Background Technology

[0002] Oil shale, as a supplementary energy source to oil and natural gas, has attracted close attention from various countries. my country possesses abundant and widely distributed oil shale resources. Leveraging the advantages of my country's high-quality oil shale resources, gentle geological formations, concentrated reserves, and stable sedimentation environments, the production of shale oil has enormous potential as a substitute for conventional energy. Oil shale carbonization is an important method for extracting shale oil from oil shale. This process generates a large amount of ash and slag, which typically reaches temperatures between 400 and 800°C. Utilizing this heat effectively is crucial for the successful carbonization of oil shale.

[0003] Patent CN213866068U discloses an oil shale pyrolysis residue treatment device, but during the use of this device, the oil shale pyrolysis residue has a relatively high temperature after being crushed, making it impossible to recover and utilize its heat.

[0004] Patent CN220393624U discloses a device for treating oil shale pyrolysis residue. This device uses a conveying assembly to transport the pyrolysis residue out and replaces the heat through cooling water pipes. However, this device does not achieve graded utilization of heat, and if the generated pyrolysis residue needs to be cooled to room temperature for subsequent processing, a large heat exchange area is required, which would significantly increase the investment in industrial applications.

[0005] A domestically developed industrial-scale shale refining unit for processing small-particle oil shale has been built and operated for many years at the Fushun Mining Bureau Shale Refinery. This unit uses Canadian ATP shale refining technology. The shale ash produced during refining is directly cooled by an ash humidifier, which sprays water onto the shale ash. The resulting quenching steam is discharged into the chimney without any water recovery. Furthermore, the preheating wastewater generated in the preheating section of the shale refining furnace, as well as the acidic water generated during subsequent oil and gas recovery processes, are sent to acidic water stripping units for wastewater treatment. The ash humidifier uses not only these two treated wastewater streams but also requires a large amount of external water to meet its needs. Summary of the Invention

[0006] To address the technical problems of heat utilization and investment reduction in the existing technology of oil shale dry distillation, this invention provides a method for heat utilization of oil shale dry distillation ash residue.

[0007] The present invention provides a method for utilizing the heat of oil shale dry distillation ash residue, comprising the following steps:

[0008] 1) After screening and washing, the oil shale first enters the preheating section of the dry distillation furnace to remove moisture and generate preheating waste gas;

[0009] 2) The preheated oil shale from step 1) enters the dry distillation section of the dry distillation furnace. After dry distillation, hydrocarbon vapor and shale ash are produced. The hydrocarbon vapor is sent to the oil and gas recovery unit to recover liquid products, gaseous products and acid water. The acid water is sent to the ash humidifier.

[0010] 3) The shale ash from step 2) exchanges heat with deoxygenated water in the slag cooler, and uses the heat of the high-temperature ash slag to generate steam;

[0011] 4) The shale ash from step 3) further enters the ash humidifier, and after being sprayed with water, it generates quenched steam and wet shale ash. The cooled wet shale ash is then conveyed to the subsequent processing via a belt.

[0012] 5) The quenching steam from step 4) and the preheated waste gas from step 1) enter the preheated waste gas condenser for condensation. The non-condensable gas enters the subsequent incineration and is discharged into the atmosphere through the chimney. The generated preheated wastewater and quenching steam condensate are returned to the ash humidifier for recycling.

[0013] 6) The heat required for dry distillation is provided by the combustion chamber through heat transfer. The fuel and air are burned in the combustion chamber of the dry distillation furnace. The flue gas produced is treated by dust removal, heat exchange, desulfurization, denitrification and other measures, and then discharged into the atmosphere through the chimney along with the exhaust gas from step 5).

[0014] The slag cooler generates steam, which can be a membrane drum cooler or other forms.

[0015] The slag cooler includes a steam generation section and a steam superheating section.

[0016] The slag cooler generates steam and can also be equipped with a flash evaporation system for gas-liquid separation of the generated steam. Additionally, it can be equipped with a condensing power generation facility to generate electricity from the produced steam.

[0017] The preheated wastewater and acidic water are not treated by acidic water stripping or other wastewater treatment processes, but are directly used in the ash humidifier.

[0018] The quenching steam is not discharged into the flue gas, but is condensed with the preheated waste gas and then recycled for use in the ash humidifier.

[0019] The present invention has the following beneficial effects:

[0020] 1) The ash residue is first used to generate steam, making full use of the heat of the high-temperature ash residue and greatly increasing the heat utilization rate of the high-temperature ash residue, thereby reducing the energy consumption of oil shale dry distillation technology and improving the economic benefits of oil shale dry distillation technology.

[0021] 2) The preheated wastewater generated during the dry distillation process and the acidic water generated during the oil and gas recovery process are used to further cool the ash residue. At the same time, the quenching steam generated during the ash humidification process is recycled, thereby achieving the purpose of water saving.

[0022] 3) Acidic water is used directly to cool ash and slag, reducing the discharge of wastewater from oil shale dry distillation technology, thereby reducing investment in subsequent wastewater treatment facilities. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0024] In the diagram: 1-Oil shale, 2-Hydrocarbon vapor, 3-Shale ash, 4-Acid water, 5-Quenching steam, 6-Preheating waste gas, 7-Non-condensable gas, 8-Preheating waste water and quenching steam condensate, 9-Flue gas, 10-Liquid product, 11-Gaseous product, 12-Wet shale ash, 13-Deoxygenated water, 14-Steam, 15-Fuel and air, 16-Waste gas after incineration, 101-Preheating section of the pyrolysis furnace, 102-Drying section of the pyrolysis furnace, 103-Oil and gas recovery unit, 104-Ash humidifier, 105-Slag cooler, 106-Preheating waste gas condenser, 107-Incineration device, 108-Flue gas treatment device, 109-Combustion chamber, 110-Chimney. Detailed Implementation

[0025] The present invention will now be further described with reference to the accompanying drawings.

[0026] The present invention provides a method for utilizing the heat of oil shale dry distillation ash residue, comprising the following steps:

[0027] 1) After screening and washing, the oil shale 1 first enters the preheating section 101 of the dry distillation furnace to remove moisture and generate preheating waste gas 6.

[0028] 2) The preheated oil shale 1 from step 1) enters the dry distillation section 102 of the dry distillation furnace. After dry distillation, hydrocarbon vapor 2 and shale ash 3 are produced. The hydrocarbon vapor 2 is sent to the oil and gas recovery unit 103 to recover liquid product 10, gas product 11 and acid water 4. The acid water 4 is sent to the ash humidifier 104.

[0029] 3) The shale ash 3 from step 2) exchanges heat with deoxygenated water 13 in slag cooler 105 to generate steam 14;

[0030] 4) Shale ash 3 from step 3) enters ash humidifier 104, and after being sprayed with water, it generates quenching steam 5. The wet shale ash 12 is sent to subsequent processing via conveyor belt.

[0031] 5) The quenching steam 5 from step 4) and the preheating waste gas 6 from step 1) enter the preheating waste gas condenser 106 for condensation. The non-condensable gas 7 enters the incineration device 107 and is discharged into the atmosphere through the chimney 110. The generated preheating wastewater and quenching steam condensate 8 are sent to the ash humidifier 104.

[0032] 6) The heat required for dry distillation is provided by the combustion chamber 109 through heat transfer. The fuel and air 15 are burned in the combustion chamber 109. The generated flue gas is treated by the flue gas treatment device 108, which includes dust removal, heat exchange, desulfurization, and denitrification, and then discharged into the atmosphere through the chimney 110 along with the incineration exhaust gas 16 from step 5).

[0033] The slag cooler 105 generates steam, which can be a membrane drum cooler or other forms.

[0034] The slag cooler 105 includes a steam generation section and a steam superheating section.

[0035] The slag cooler 105 generates steam and can also be equipped with a flash evaporation system for gas-liquid separation of the generated steam. It can also be equipped with a condensing power generation facility to generate electricity from the produced steam.

[0036] The preheated wastewater and acidic water are not treated by acidic water stripping or other wastewater treatment processes, but are directly used in the ash humidifier.

[0037] The quenching steam 5 is not discharged into the flue gas, but is condensed with the preheated waste gas and then recycled to the ash humidifier 104.

[0038] like Figure 1 As shown, the processed oil shale 1 first enters the preheating section 101 of the dry distillation furnace, where it is gradually heated to initially remove surface moisture. The preheated oil shale then enters the dry distillation section 102 of the dry distillation furnace, where the oil shale is rapidly heated for dry distillation. After dry distillation, hydrocarbon vapor 2 and shale ash 3 are produced. The hydrocarbon vapor 2 is sent to the oil and gas recovery unit 103 to recover liquid product 10, gaseous product 11, and acid water 4. The acid water 4 is then sent to the ash humidifier 104.

[0039] Shale ash 3 produced by dry distillation flows into slag cooler 105 and exchanges heat with deoxygenated water 13, generating steam 14. The shale ash after heat exchange enters ash humidifier 104, and after being sprayed with water, generates quench steam 5. The wet shale ash 12 is sent to subsequent treatment. The quench steam 5 and the preheated waste gas 6 generated by the dry distillation furnace preheating section 101 enter the preheated waste gas condenser 106 for condensation. The non-condensable gas 7 enters the subsequent incineration unit 107 for treatment and is then discharged into the atmosphere through chimney 110. The preheated wastewater and quench steam condensate 8 generated by condensation are sent to ash humidifier 104.

[0040] The heat required by the dry distillation furnace is provided by the combustion chamber 109 through heat transfer. The fuel and air 15 are burned in the combustion chamber 109 of the dry distillation furnace. The resulting flue gas 9 is treated by the flue gas treatment device 108 through dust removal, heat exchange, desulfurization, denitrification and other measures, and then discharged into the atmosphere through the chimney 110 along with the exhaust gas 16 from the incineration device 107.

[0041] The above description is merely a typical embodiment of the present invention and does not impose any limitation on the present invention. Any changes or modifications made by those skilled in the art based on the above content without departing from the scope of the present invention should be considered equivalent examples of equivalent variations. Any equivalent changes made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention are all within the scope of the present invention.

Claims

1. A method for utilizing the heat of oil shale dry distillation ash residue, characterized in that: The method includes the following steps: 1) After screening and washing, the oil shale first enters the preheating section of the dry distillation furnace to remove moisture and generate preheating waste gas; 2) The preheated oil shale from step 1) enters the dry distillation section of the dry distillation furnace. After dry distillation, hydrocarbon vapor and shale ash are produced. The hydrocarbon vapor is sent to the oil and gas recovery unit to recover liquid products, gaseous products and acid water. The acid water is sent to the ash humidifier. 3) The shale ash from step 2) exchanges heat with deoxygenated water in the slag cooler, and uses the heat of the high-temperature ash slag to generate steam; 4) The shale ash from step 3) further enters the ash humidifier, and after being sprayed with water, it generates quenched steam and wet shale ash. The cooled wet shale ash is then conveyed to the subsequent processing via a belt. 5) The quenching steam from step 4) and the preheated waste gas from step 1) enter the preheated waste gas condenser for condensation. The non-condensable gas enters the subsequent incineration and is discharged into the atmosphere through the chimney. The generated preheated wastewater and quenching steam condensate are returned to the ash humidifier for recycling. 6) The heat required for dry distillation is provided by the combustion chamber through heat transfer. The fuel and air are burned in the combustion chamber of the dry distillation furnace. The flue gas produced is treated by dust removal, heat exchange, desulfurization, denitrification and other measures, and then discharged into the atmosphere through the chimney along with the exhaust gas from step 5).

2. The method for utilizing the heat of oil shale dry distillation ash residue according to claim 1, characterized in that: The slag cooler generates steam, which can be a membrane drum cooler or other forms.

3. The method for utilizing the heat of oil shale dry distillation ash residue according to claim 1, characterized in that: The slag cooler includes a steam generation section and a steam superheating section.

4. The method for utilizing the heat of oil shale dry distillation ash residue according to claim 1, characterized in that: The slag cooler generates steam and is equipped with a flash evaporation system for gas-liquid separation of the generated steam, or is equipped with a condensing power generation facility to generate electricity from the produced steam.

5. The method for utilizing the heat of oil shale dry distillation ash residue according to claim 1, characterized in that: The preheated wastewater and acidic water are not treated with acidic water stripping wastewater, but are used directly in the ash humidifier.

6. The method for utilizing the heat of oil shale dry distillation ash residue according to claim 1, characterized in that: The quenching steam is not discharged into the flue gas, but is condensed with the preheated waste gas and then recycled for use in the ash humidifier.

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