Oil shale and high-sodium coal coupling deep processing system and process

Abstract

The invention provides an oil shale and high-sodium coal coupling deep processing system and process, which can effectively solve the comprehensive utilization problem of oil shale and the problem existing when high-sodium coal is used as coal for gasification, and also can realize efficient utilization of energy. The system comprises a drying and dehydrating unit, a dry distillation unit, a deep processing unit, a water-kerosene oil slurry preparation unit and a gasification unit, the drying and dehydrating unit is used for drying and dehydrating the oil shale; the dry distillation unit is used for receiving the dried oil shale and performing dry distillation on the dried oil shale; the deep processing unit is used for performing oil-water separation and processing on shale oil; the water-kerosene oil slurry preparation unit is used for receiving high-sodium coal, oil shale semicoke and oily wastewater and preparing water-kerosene oil slurry; the gasification unit is used for carrying out gasification reaction on the water-kerosene oil slurry and a gasification agent; the gasification unit and the dry distillation unit are connected through a synthesis gas output pipe; the dry distillation unit is connected with the drying dehydration unit through a coal gas output pipe.

Description

Technical Field

[0001] The invention relates to the technical field of deep processing of oil shale and high-sodium coal, and in particular to a system and process for coupling deep processing of oil shale and high-sodium coal. Background Art

[0002] During the gasification process of high-sodium coal, there are problems such as slagging, ash accumulation, pipe wall contamination, and high-temperature corrosion. Entrained-bed gasification technology has the characteristics of high gasification temperature, high gasification pressure, and a wide range of coal types, and has become the mainstream direction of coal gasification technology development. Due to its high gasification temperature, the temperature for producing synthesis gas is also high, and the fly ash particles remain in a molten state. During the quenching process, when the quenching amount is insufficient or the quenching temperature is too high, the molten fly ash is easy to stick to the surface of the heat exchanger, and the bonded fly ash continues to adhere to the remaining fly ash particles, eventually leading to the deposition of fly ash. Therefore, the ash accumulation problem on the surface of the heat exchanger becomes an important factor affecting the efficient and stable operation of the entrained-bed gasifier. How to reduce the negative effects of the sodium element in high-sodium coal during coal processing and utilization is the main technical issue in achieving the clean utilization of high-sodium coal with abundant reserves.

[0003] The main purpose of oil shale development and utilization is to produce shale oil. Currently, the main technology used is low-temperature distillation. However, the main bottleneck restricting the development of this technology is the utilization of coal gas and distillation waste residue, especially the recovery and utilization of fixed carbon in oil shale semi-coke. Oil shale contains a large amount of minerals, so the amount of shale ash produced by combustion or distillation is large, accounting for almost 60%-80% of the oil shale treatment volume. In the process of development and utilization, if the ash is not utilized, it will inevitably become an obstacle to the development of the industry. In addition, the wastewater produced by oil shale distillation contains oily substances, water-soluble organic matter and inorganic matter, which is difficult to treat with industrial technology at present. Even if it is treated, it is difficult to meet the national emission standards, and it occupies a large area and has a high cost.

[0004] CN116557851A discloses a combustion system and process for ultra-low calorific value oil shale and oil shale dry distillation semi-coke, which belongs to the technical field of oil shale resource utilization; it includes a fluidized bed boiler, a cyclone separator is arranged at the outlet of the fluidized bed boiler, a return device is connected to the bottom of the cyclone separator, and the return device is connected to the fluidized bed boiler through a return inclined pipe; the top of the cyclone separator is connected to the flue gas pipeline; the coal feed bin is connected to the fluidized bed boiler through the first coal conveying pipeline, and is connected to the return inclined pipe through the second coal conveying pipeline; a superheater and an evaporation heating surface are arranged at the top of the flue gas pipeline, and an air preheater and an economizer are arranged at the bottom of the flue gas pipeline; a primary air box is arranged at the bottom of the fluidized bed boiler, and a secondary air box is arranged on the front and rear walls and / or the two side walls of the water-cooled wall of the fluidized bed boiler; the flue gas pipeline is connected to the primary air box and the secondary air box. The present invention improves the combustion efficiency of the boiler on the basis of ensuring the ignition, stable combustion and burnout of ultra-low calorific value fuel. This invention uses oil shale and oil shale semi-coke for direct combustion, which has a low added value for the use of oil shale. In addition, due to the high ash content of oil shale, the ash treatment method is different from that of the gasification process (gasification uses liquid slag discharge and fly ash washing). The amount of fly ash is large when it is directly burned, which increases the subsequent ash treatment load of the boiler and is prone to scaling of the equipment.

[0005] CN117165334A discloses a method for reducing the release of sodium in high-alkali coal, the method is as follows: high-alkali coal and additives are crushed and sieved to obtain 160-200 mesh particles, and the high-alkali coal and additives are uniformly mixed in proportion. The additive is added in a proportion of 1-10% of the high-alkali coal, including 5-10% of silicon dioxide, 5-10% of aluminum oxide and 80-90% of phosphorus-containing additives; the mixed material is gasified in a high-temperature plane flame entrained flow reactor to illustrate the influence of additives on the release characteristics of alkali metal sodium in high-alkali coal under real fluidized bed gasification conditions. The present invention can effectively inhibit the release of alkali metal sodium in high-alkali coal and increase the melting temperature of gasified ash, effectively alleviate the problems of dust accumulation, contamination, corrosion, etc. caused by the release of alkali metal sodium in the gasification process of high-alkali coal, and contribute to the resource utilization of high-alkali coal.

[0006] CN114854437B discloses a method and system for reducing the slagging characteristics of high-sodium coal. By pre-pyrolyzing the high-sodium coal, the content of residual sodium substances in the high-sodium coal is reduced, the formation of high-melting-point sodium-containing aluminosilicates is promoted, and the slagging tendency of the high-sodium coal is reduced from the source. Since the insoluble sodium in the form of aluminosilicates has a high melting point and thermal stability, the harm during the combustion process is small, and the high-quality and clean utilization of coal is achieved. On the one hand, the present invention provides a method for reducing the slagging characteristics of high-sodium coal based on pyrolysis and combustion coupling technology, comprising the following steps: mixing the high-sodium coal with a heat carrier from a combustion furnace in a pyrolysis furnace and causing a pyrolysis reaction, and the fluidizing medium of the pyrolysis furnace is coal gas. The second aspect of the present invention also provides a system for reducing the slagging characteristics of high-sodium coal based on pyrolysis and combustion coupling technology, the system comprising: a combustion furnace that generates a heat carrier; a pyrolysis furnace that mixes the high-sodium coal and the heat carrier and causes a pyrolysis reaction, wherein the fluidizing medium of the pyrolysis furnace is coal gas. The invention first pyrolyzes the high-sodium coal to reduce the sodium content in the coal. However, the coal pyrolysis process is a process in which light components volatilize to generate coke, condensable liquids and gas products in an oxygen-free or low-oxygen environment. Generally, most of the sodium in high-sodium coal is water-soluble, so it is very easy to volatilize with the light components, causing scaling or blockage of the process pipelines and equipment of the downstream light components after pyrolysis, causing the pyrolysis process to be unable to operate continuously. Therefore, the invention only transfers the existing problems from one process to another, and cannot really solve the problems of high-sodium coal. Summary of the invention

[0007] The present invention provides a system and process for coupling deep processing of oil shale and high-sodium coal. The system and process of the present invention can not only effectively solve the problem of comprehensive utilization of oil shale, but also solve the problem of using high-sodium coal as gasification coal. At the same time, efficient utilization of energy can be achieved through clever coupling.

[0008] To achieve the purpose, the present invention provides the following technical solutions:

[0009] The present invention provides an oil shale and high sodium coal coupled deep processing system, the system comprising a drying and dehydration unit, a dry distillation unit, a deep processing unit, a water-coal-oil slurry preparation unit and a gasification unit;

[0010] The drying and dehydration unit is used to dry and dehydrate the crushed oil shale to obtain dried oil shale;

[0011] The dry distillation unit is used to receive the dried oil shale and dry distill it to obtain coal gas, shale oil and oil shale semi-coke;

[0012] The deep processing unit is used to separate oil from water and process the shale oil to obtain oily wastewater and oil products;

[0013] The water-coal-oil slurry preparation unit is used to receive the high-sodium coal, the oil shale semi-coke and the oily wastewater and prepare the water-coal-oil slurry;

[0014] The gasification unit is used to gasify the water-kerosene slurry and the gasification agent to obtain synthesis gas and gasified slag;

[0015] The gasification unit and the dry distillation unit are connected via a synthesis gas output pipe, which is used to perform heat exchange between the synthesis gas obtained by the gasification unit and the dry distillation unit; the dry distillation unit and the drying and dehydration unit are connected via a coal gas output pipe, which is used to pass the coal gas obtained by the dry distillation unit as fuel into the drying and dehydration unit for combustion to provide heat.

[0016] Preferably, it also includes a mixing unit for receiving the high-sodium coal and the oil shale semi-coke obtained by the distillation unit and pre-mixing the two; the water-coal-oil slurry preparation unit is connected to the mixing unit to receive the pre-mixed high-sodium coal and the oil shale semi-coke.

[0017] Preferably, it further comprises a dust removal and purification unit for removing dust and purifying the synthesis gas that has undergone heat exchange with the dry distillation unit to obtain purified synthesis gas.

[0018] In some embodiments, the synthesis gas obtained by the gasification unit is heat exchanged with the dry distillation unit by indirect heat exchange.

[0019] Preferably, it also includes a gasified slag processing unit for processing building materials using the gasified slag as raw material.

[0020] The present invention also provides a process for coupling deep processing of oil shale and high-sodium coal using the above-mentioned oil shale and high-sodium coal coupling deep processing system, comprising the following steps:

[0021] After the oil shale is crushed, it is sent to the drying and dehydration unit for drying and dehydration to obtain dried oil shale; the heat required by the drying and dehydration unit is the heat generated by the combustion of the coal gas obtained in the dry distillation unit;

[0022] The dried oil shale is sent to the dry distillation unit for dry distillation to obtain coal gas, shale oil and oil shale semi-coke; the dry distillation unit obtains heat required for the dry distillation by heat exchange with the synthesis gas obtained from the gasification unit; the coal gas is output to the drying and dehydration unit through the coal gas output pipe for combustion to provide heat required for the drying and dehydration;

[0023] The shale oil is sent to the deep processing unit for oil-water separation and processing to obtain oily wastewater and oil products;

[0024] Prepare a water-kerosene slurry by using high sodium coal, the oil shale semi-coke and the oily wastewater in the water-kerosene slurry preparation unit;

[0025] The water-kerosene slurry is sent to the gasification unit to undergo a gasification reaction with a gasifying agent to obtain synthesis gas and gasified slag; the synthesis gas obtained by the gasification unit is output through the synthesis gas output pipe and undergoes heat exchange with the dry distillation unit.

[0026] Preferably, the high sodium coal and the oil shale semi-coke are pre-mixed in a mixing unit and then fed into the water-coal-oil slurry preparation unit;

[0027] and / or, sending the synthesis gas that has completed the heat exchange in the dry distillation unit to a dust removal and purification unit for dust removal and purification to obtain purified synthesis gas; preferably, the purified synthesis gas is used as a synthetic raw material for producing chemicals;

[0028] And / or, the gasified slag is fed into a gasified slag processing unit, and the gasified slag is used as a raw material for processing building materials.

[0029] Furthermore, the gasification temperature of the gasification unit for performing the gasification reaction is 1200° C. to 1500° C., and the gasification pressure is 4.0 to 8.5 MPa, preferably the gasification pressure is 4.0 to 6.0 MPa.

[0030] Preferably, the gasification temperature is 1250°C to 1350°C.

[0031] In some embodiments, the moisture content of the dried oil shale is less than 6 wt%, preferably less than 3 wt%;

[0032] And / or, the drying temperature of the drying and dehydration unit for the drying and dehydration is 100-200° C., preferably 105-120° C.;

[0033] And / or, the dry distillation temperature in the dry distillation unit is 400-600°C, preferably 450-500°C;

[0034] and / or, in the dry distillation unit, the temperature of the synthesis gas after the heat exchange is 600° C. to 800° C.;

[0035] And / or, in the deep processing unit, the oil product obtained includes diesel and / or gasoline;

[0036] And / or, when preparing the water-coal-oil slurry, the ratio of the mass of the oil shale semi-coke used to the mass of the high-sodium coal used does not exceed 15:100;

[0037] And / or, the solid content of the water-kerosene slurry is not less than 50 wt %, preferably 50-70 wt %, more preferably 60-65 wt %.

[0038] The technical solution provided by the present invention has the following beneficial effects:

[0039] The system and process of the present invention can be used to solve the problems of efficient and comprehensive utilization of existing oil shale resources and the applicability of high-sodium coal as gasification coal. The crushed oil shale is dried and dehydrated in a drying and dehydration unit, and then enters a distillation unit for distillation. The coal gas produced by distillation is returned to the drying and dehydration unit for combustion and heat supply, and the shale oil produced by distillation is sent to a deep processing unit for treatment to obtain oil products and oily wastewater; the oil shale semi-coke and high-sodium coal produced by distillation are mixed with the oily wastewater of the deep processing unit to form a water-coal oil slurry, and then a gasification reaction occurs with a gasifier, and the high-temperature synthesis gas produced by the reaction is passed to the distillation unit for heat exchange and heating. Through the coupling system of the present invention, not only can the oil shale be fully and deeply utilized, but also the problem that high-sodium coal as gasification coal is easy to cause fly ash deposition and scaling, which makes it difficult for the gasifier to operate stably for a long period of time is solved. At the same time, the present invention also realizes efficient utilization of energy in the system through clever coupling. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of a coupled deep processing system of oil shale and high-sodium coal in one embodiment. DETAILED DESCRIPTION

[0041] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with examples. It should be understood that the following examples are only for a better understanding of the present invention and do not mean that the present invention is limited to the following examples.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the invention belongs. The term "and / or" as may be used herein includes any and all combinations of one or more of the associated listed items.

[0043] See also Figure 1 , the present invention provides a coupled deep processing system of oil shale and high sodium coal, the system mainly comprises a drying and dehydration unit, a dry distillation unit, a deep processing unit, a water-coal-oil slurry preparation unit and a gasification unit;

[0044] The drying and dehydration unit is used to dry and dehydrate the crushed oil shale to obtain dried oil shale;

[0045] The dry distillation unit is used to receive the dried oil shale obtained in the drying and dehydration unit, and dry distill the dried oil shale to obtain coal gas, shale oil and oil shale semi-coke;

[0046] The deep processing unit is used to separate and process the shale oil obtained from the distillation unit, thereby obtaining oily wastewater and oil products, such as gasoline and / or diesel;

[0047] The water-kerosene slurry preparation unit is used to receive high-sodium coal, oil shale semi-coke obtained from the dry distillation unit and oily wastewater obtained from the deep processing unit, and prepare water-kerosene slurry to obtain water-kerosene slurry;

[0048] The gasification unit is used to gasify the water-kerosene slurry obtained by the water-kerosene slurry preparation unit with a gasifying agent to obtain synthesis gas and gasified slag;

[0049] The gasification unit and the dry distillation unit are connected through a synthesis gas output pipe, which is used to perform heat exchange between the synthesis gas obtained by the gasification unit and the dry distillation unit, specifically, to perform heat exchange with the dry distillation reactor in the dry distillation unit, thereby providing the heat required by the dry distillation unit; the dry distillation unit and the drying and dehydration unit are connected through a coal gas output pipe, which is used to pass the coal gas obtained by the dry distillation unit as fuel into the drying and dehydration unit for combustion, thereby providing the heat required for drying and dehydration for the drying and dehydration unit through the combustion of coal gas.

[0050] Preferably, it also includes a mixing unit for receiving the high-sodium coal and the oil shale semi-coke obtained by the distillation unit and pre-mixing the two; the water-coal-oil slurry preparation unit is connected to the mixing unit to receive the high-sodium coal and oil shale semi-coke pre-mixed in the mixing unit, that is, the high-sodium coal and oil shale semi-coke are pre-mixed in the mixing unit and then sent to the water-coal-oil slurry preparation unit.

[0051] Preferably, it also includes a dust removal and purification unit for removing dust and purifying the synthesis gas that has undergone heat exchange with the dry distillation unit, thereby obtaining purified synthesis gas, which can be used as a raw material for synthesizing chemicals (such as C1 chemicals).

[0052] In some specific embodiments, the synthesis gas obtained by the gasification unit is heat exchanged with the dry distillation unit by indirect heat exchange, thereby providing heat for the dry distillation unit.

[0053] Preferably, it also includes a gasified slag processing unit for processing the gasified slag as raw material into building materials.

[0054] The system of the present invention can well balance the problems of efficient and comprehensive utilization of existing oil shale resources and the applicability of high-sodium coal as gasification coal. The crushed oil shale is dried and dehydrated in a drying and dehydration unit, and then enters a distillation unit for distillation. The coal gas produced by distillation is returned to the drying and dehydration unit for combustion and heat supply. The shale oil produced by distillation is sent to a deep processing unit for processing to obtain gasoline, diesel and other oil products and oily wastewater; the oil shale semi-coke produced by distillation and high-sodium coal are mixed, and then mixed with the oily wastewater of the deep processing unit to form a water-coal oil slurry, and then sent to the gasification unit together with the gasification agent for gasification reaction. The high-temperature synthesis gas produced by the reaction is introduced into the distillation unit for heat exchange and heating. The synthesis gas can be used for synthesizing chemicals after purification, and the gasified slag produced by gasification can be used to produce building materials. Through the coupling system of the present invention, not only can the oil shale be fully and comprehensively utilized, but also the problem that high-sodium coal as gasification coal easily causes fly ash deposition and scaling, which makes it difficult for the gasifier to operate stably for a long period of time is solved. At the same time, the coupling process of the present invention also realizes the efficient utilization of energy in the system.

[0055] The present invention also provides a process for coupling deep processing of oil shale and high-sodium coal using the above-mentioned oil shale and high-sodium coal coupling deep processing system, comprising the following steps:

[0056] After the oil shale is crushed, for example, to a particle size of 10-50 mm, it is sent to a drying and dehydration unit for drying and dehydration to obtain dried oil shale; the heat required for the drying and dehydration unit for drying and dehydration is the heat generated by the combustion of the coal gas obtained in the dry distillation unit;

[0057] The dried oil shale is sent to the dry distillation unit for dry distillation to obtain coal gas, shale oil and oil shale semi-coke; the dry distillation unit obtains the heat required for dry distillation by heat exchange with the high-temperature synthesis gas obtained from the gasification unit; the coal gas obtained from the dry distillation unit is output to the drying and dehydration unit through the coal gas output pipe for combustion, and the heat required for drying and dehydration in the drying and dehydration unit is provided by the combustion of the coal gas;

[0058] The shale oil obtained from the distillation unit is sent to the deep processing unit for oil-water separation and processing to obtain oily wastewater and oil products, such as gasoline and / or diesel oil; the processing is, for example, hydrogenation of the crude oil obtained from the oil-water separation to obtain gasoline, diesel oil, etc. The conventional techniques known in the art can be used to separate and process shale oil to obtain gasoline, diesel oil, etc., and there is no particular limitation on this, so it will not be described in detail.

[0059] The high sodium coal, the oil shale semi-coke obtained from the dry distillation unit and the oily wastewater obtained from the deep processing unit are sent to the water-kerosene slurry preparation unit to prepare the water-kerosene slurry;

[0060] The water-kerosene slurry prepared by the water-kerosene slurry preparation unit is sent to the gasification unit to undergo a gasification reaction with a gasifying agent to obtain synthesis gas and gasified slag; the high-temperature synthesis gas obtained by the gasification unit is output through a synthesis gas output pipe and heat exchanged with the distillation unit, thereby providing heat for the distillation unit.

[0061] Preferably, the high sodium coal and the oil shale semi-coke are pre-mixed in a mixing unit and then sent to a water-kerosene slurry preparation unit for preparation of the water-kerosene slurry.

[0062] Preferably, the synthesis gas that has completed heat exchange in the dry distillation unit is sent to a dust removal and purification unit for dust removal and purification to obtain purified synthesis gas; the purified synthesis gas is used as a synthetic raw material to produce chemicals, such as C1 chemicals.

[0063] Preferably, the gasified slag obtained from the gasification unit is fed into a gasified slag processing unit, and the gasified slag is used as a raw material for processing building materials, such as cement, bricks, gypsum, and the like.

[0064] Specifically, the gasification temperature of the gasification unit for the gasification reaction is 1200°C to 1500°C, the gasification pressure is 4.0 to 8.5 MPa, and the preferred gasification pressure is 4.0 to 6.0 MPa. Preferably, the gasification temperature is 1250°C to 1350°C. With the preferred gasification temperature, the water-coal-oil slurry prepared by oil shale semi-coke, high-sodium coal and oily wastewater has a better gasification effect, which is not only conducive to obtaining a higher synthesis gas output and a higher effective gas content in the synthesis gas, but also does not cause intermittent slag blocking caused by poor slag discharge, and does not require more stringent refractory requirements for the gasifier, which is conducive to extending the life of the gasifier, improving the process operation stability, and further extending the stable operation cycle. The inventors have found that when the water-coal-oil slurry prepared by mixing high-sodium coal and oil shale semi-coke is gasified in a gasifier, the gasification temperature is lower than 1250°C. Compared with the case where the gasification temperature is controlled at 1250°C to 1350°C, the CO and H in the syngas are reduced. 2 The content will decrease, the overall synthesis gas output will decrease, and the high-temperature molten slag will not be discharged smoothly, resulting in intermittent slag blockage; when the gasification temperature is higher than 1350℃, compared with the gasification temperature controlled at 1250℃~1350℃, although it will increase the effective gas content and synthesis gas output in the synthesis gas, the higher gasification temperature also causes the gasifier to have more stringent refractory requirements, which is not conducive to extending the life of the gasifier.

[0065] Specifically, the drying and dehydration unit can use a rotary kiln for drying and dehydration. For example, the oil shale rolls in a rotary kiln, and gas is burned in the middle to provide heat for dehydration, which is used to heat the oil shale particles for dehydration. In some examples, the drying temperature of the drying and dehydration unit for drying and dehydration is 100-200°C, preferably 105-120°C. In some examples, the moisture content of the dried oil shale obtained in the drying and dehydration unit is less than 6wt%, preferably less than 3wt%.

[0066] The heat required by the distillation unit comes from the waste heat of the high-temperature synthesis gas generated by the gasification unit. Preferably, the synthesis gas generated by the gasification unit is indirectly heat-exchanged with the distillation reactor in the distillation unit, for example, the high-temperature synthesis gas is passed through the tube side, and the oil shale particles are passed through the shell side. In some examples, the distillation temperature in the distillation unit is 400-600°C, preferably 450-500°C; in the distillation unit, the temperature of the synthesis gas after heat exchange is 600°C-800°C.

[0067] Preferably, when preparing the water-coal oil slurry, the ratio of the mass of the oil shale semi-coke used to the mass of the high-sodium coal used does not exceed 15:100, for example 0.1:100, 1:100, 5:100, 10:100, 13:100, 15:100, etc.

[0068] In some examples, the solid content of the water-kerosene slurry prepared in the water-kerosene slurry preparation unit is not less than 50wt%, preferably 50-70wt%, and more preferably 60-65wt%. The prepared water-kerosene slurry is transported to the gasification unit via a coal slurry pump. Specifically, the gasification unit can use an entrained flow gasifier. The gasification agent used in the gasification unit is, for example, oxygen.

[0069] In the system and process of the present invention, the specific equipment or specific operations involved, which are not particularly explained, are all existing technologies or conventional technologies well known to those skilled in the art, and will not be described in detail.

[0070] Compared with the prior art, the oil shale and high sodium coal coupled deep processing system and process provided by the present invention has the following beneficial technical effects:

[0071] (1) The waste heat carried by the high-temperature synthesis gas generated by the gasifier in the gasification unit is used to provide heat for the oil shale distillation, so that the heat energy of the entire gasification process is fully utilized without affecting the distillation and gasification performances, and the overall process efficiency is high;

[0072] (2) The main component of oil shale semi-coke is SiO 2 and Al 2 O 3The present invention ingeniously mixes high-sodium coal with oil shale semi-coke so that most of the sodium eventually exists in the form of aluminosilicate, thereby reducing the deposition tendency of fly ash; in addition, if oil shale is directly mixed with high-sodium coal for gasification in a gasification unit, it will make it difficult to deeply utilize the oil shale, for example, it will lead to the inability to produce shale oil, and the oil shale has a high oil content. Directly mixing it with high-sodium coal will cause high viscosity and difficulty in grinding to obtain a water-coal-oil slurry suitable for gasification. The present invention ingeniously distills the oil shale to extract shale oil first, and then mixes the oil shale semi-coke with the high-sodium coal. The above-mentioned disadvantages do not exist, shale oil can be produced, and the generated coal gas can also be burned as fuel to provide heat in the system, and the problem of easy scaling in high-sodium coal gasification that makes it difficult for the system to operate stably for a long period of time can be solved.

[0073] (3) The wastewater generated by the deep processing of shale oil contains oily substances, water-soluble organic matter and inorganic matter, which are difficult to treat with current industrial technology. Even if treated, it is difficult to meet the national emission standards, and it occupies a large area and has high costs. The present invention cleverly mixes it with high-sodium coal and oil shale semi-coke to form a water-coal-oil slurry, and through gasification treatment, it not only solves the environmental protection problem of wastewater treatment, but also increases the production of gasification synthesis gas.

[0074] (4) Oil shale semi-coke is rich in organic matter, and using it for gasification can also make the most of the oil shale. The coupling of the entire process not only produces qualified oil products, but also produces rich synthesis gas (C1 chemical synthesis raw material), and the process energy consumption is low, so the overall process added value is significantly improved.

[0075] The present invention is further described below by way of examples, but it should not be understood that the present invention is limited thereto.

[0076] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental steps or conditions in the art can be used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be purchased commercially.

[0077] Example 1

[0078] This embodiment adopts Figure 1 The system shown is used for deep processing of oil shale and high sodium coal. Figure 1 The description of the system shown is given above and will not be repeated here.

[0079] Taking the gasifier pressure of 4.0MPa, the processing capacity of a single gasifier of 2000 tons / day as an example, and the oil shale retorting processing capacity of 300 tons / day as an example, the properties of the raw coal and oil shale used are shown in Tables 1 and 2 below:

[0080] Table 1 Industrial analysis and elemental analysis of raw materials

[0081]

[0082] Table 2 Raw material ash composition / wt%

[0083] raw material <![CDATA[SiO 2 ]]> <![CDATA[Al 2 THE 3 ]]> <![CDATA[Fe 2 THE 3 ]]> CaO MgO <![CDATA[TiO 2 ]]> <![CDATA[SO 3 ]]> <![CDATA[K 2 The]]> <![CDATA[Na 2 The]]> <![CDATA[P 2 THE 3 ]]> High sodium coal 18.25 9.81 24.93 11.96 6.50 0.52 19.45 0.35 6.36 0.06 Oil shale 63.32 28.12 2.25 2.05 0.31 1.22 0.40 0.22 0.40 0.09

[0084] The deep processing steps of this embodiment are as follows:

[0085] After the oil shale is crushed to a particle size of 20-30 mm, it is sent to a drying and dehydration unit for drying and dehydration. The heat required by the drying and dehydration unit is the heat generated by the combustion of the coal gas obtained in the distillation unit as fuel in the drying and dehydration unit, and the oil shale particles are heated by the combustion of the coal gas; the drying temperature is 105-110°C; the moisture content of the dried oil shale is 3wt%.

[0086] The dried oil shale is sent to the distillation unit for distillation to obtain coal gas, shale oil and oil shale semi-coke; the distillation unit obtains the heat required for distillation by indirect heat exchange with the synthesis gas obtained from the gasification unit; the coal gas obtained from the distillation unit is output to the drying and dehydration unit through the coal gas output pipe for combustion to provide heat for the drying and dehydration unit; the distillation temperature in the distillation unit is 500°C, the distillation pressure is normal pressure, and the distillation processing capacity is 300t / d.

[0087] The shale oil is sent to the deep processing unit for oil-water separation to obtain oily wastewater and crude oil, and the crude oil is processed to obtain diesel, gasoline and other oil products;

[0088] The high sodium coal and the oil shale semi-coke are pre-mixed in a mixing unit to obtain a mixture, wherein the mixing mass ratio of the high sodium coal to the oil shale semi-coke is 22:3, and then the obtained mixture and the oily wastewater are mixed in a water-kerosene slurry preparation unit to prepare a water-kerosene slurry, and the solid concentration of the obtained water-kerosene slurry is 60wt%;

[0089] The water-kerosene slurry is sent to the gasification unit (using an entrained flow gasifier) ​​to react with oxygen as a gasifying agent. The gasification temperature is 1350°C, the gasification pressure is 4.0MPa, and the processing capacity of the gasifier is 2000t / d. Synthesis gas and gasification slag are obtained in the gasification unit. The synthesis gas obtained by the gasification unit is output through the synthesis gas output pipe and heat exchanged with the distillation unit. The temperature of the synthesis gas after heat exchange with the distillation unit is about 800°C. The synthesis gas is sent to the dust removal and purification unit. After dust removal and purification, it is used as a synthetic raw material for C1 chemicals downstream. The gasification slag is sent downstream for processing building materials.

[0090] The experimental results are as follows:

[0091] The main components of the syngas produced by the gasifier (mol%) are: CO: 53%, H 2 :36%、CO 2 : 11%;

[0092] Gasifier synthesis gas production: 4.2×10 6 Nm 3 / d;

[0093] Composition of coal gas produced by the carbonization unit (mol%): CO: 13%, H 2 :12.0%、CO 2 :30%、CH 4 :12.0%、C n H m :20%、N 2 :13%; among them, C n H m n=2-3, m=4-8 (C in each embodiment and comparative example n H m At the same time, I will not go into details one by one)

[0094] Gas production of distillation unit: 2.8×10 4 Nm 3 / d;

[0095] Deep processing unit diesel, gasoline and other oil product output: 10.5t / d;

[0096] It can be seen from the above process indicators that the oil shale and high sodium coal coupled deep processing process of the present invention makes it almost unnecessary to add additional heat to the oil shale distillation process, and also produces 10.5t / d of oil products as a by-product; and for the gasification process, the ash composition of high sodium coal and oil shale semi-coke mixed at a mass ratio of 22:3 is shown in Table 3:

[0097] Table 3 Ash composition of high sodium coal and oil shale semi-coke mixed at a mass ratio of 22:3 (wt%)

[0098] <![CDATA[SiO 2 ]]> <![CDATA[Al 2 THE 3 ]]> <![CDATA[Fe 2 THE 3 ]]> CaO MgO <![CDATA[TiO 2 ]]> <![CDATA[SO 3 ]]> <![CDATA[K 2 The]]> <![CDATA[Na 2 The]]> <![CDATA[P 2 THE 3 ]]> 45.03 20.69 11.46 6.07 2.82 0.94 8.13 0.27 2.82 0.08

[0099] It can be seen from Table 3 that after mixing, the sodium content in the high-sodium coal is reduced from 6.36% to 2.82%, and the silicon and aluminum content is increased from the original 28% to about 66%. The total potassium and sodium content after mixing fully meets the requirements of the group standard T / CCT 015-2024 "Coal for fluidized bed water-coal slurry gasification" for coal ash potassium and sodium content ≤3.5%. In addition, the use of the mixed coal sample as a gasification raw material achieved stable and long-term operation of the process system during the gasification operation, and there were no problems such as scaling and slag blockage caused by raw material problems. At the same time, the fly ash generated during the gasification operation in this embodiment was sampled and analyzed, and the results are shown in Table 4:

[0100] Table 4 Gasification operation fly ash composition / wt%

[0101] <![CDATA[SiO 2 ]]> <![CDATA[Al 2 THE 3 ]]> <![CDATA[Fe 2 THE 3 ]]> CaO MgO <![CDATA[TiO 2 ]]> <![CDATA[SO 3 ]]> <![CDATA[K 2 The]]> <![CDATA[Na 2 The]]> <![CDATA[P 2 THE 3 ]]> 45.36 19.84 13.43 6.25 2.92 0.82 7.21 0.16 2.05 0.32

[0102] It can also be seen from the above table that, compared with the composition of the fly ash after mixing and the coal ash entering the furnace, the potassium and sodium contents are reduced, especially the sodium content is reduced from 2.82% to 2.05%, which shows that potassium and sodium alkali metals are not enriched in the fly ash. Through the process of the present invention, most of the sodium can be present in the form of aluminosilicates, so that high-sodium coal can be fully used as gasification coal without the occurrence of problems such as fly ash deposition and scaling, and the energy efficiency of the entire process is fully utilized.

[0103] Example 2

[0104] The process is carried out in accordance with Example 1, except that the gasification temperature of the gasification unit is 1200°C.

[0105] The experimental results are as follows:

[0106] The main components of the syngas produced by the gasifier (mol%) are: CO: 51%, H 2 :33%、CO 2 : 16%;

[0107] Gasifier synthesis gas production: 4.12×10 6 Nm 3 / d;

[0108] Composition of coal gas produced by the carbonization unit (mol%): CO: 13%, H 2 :12.0%、CO 2 :30%、CH 4 :12.0%、C n H m :20%、N 2 : 13%;

[0109] Gas production of distillation unit: 2.8×10 4 Nm 3 / d;

[0110] Deep processing unit diesel, gasoline and other oil products output: 10.5t / d

[0111] From the above indicators, it can be seen that when the gasification temperature is operated at 1200℃, CO and H 2 The content of CO was lower than that of Example 1. 2 The content of increases, resulting in a decrease in the overall synthesis gas output. In addition, when the gasification temperature is 1200°C, compared with Example 1, there is a phenomenon that the high-temperature slag in the gasifier is not discharged smoothly.

[0112] Example 3

[0113] The process is carried out in accordance with Example 1, except that the gasification temperature of the gasification unit is 1400°C.

[0114] The experimental results are as follows:

[0115] The main components of the syngas produced by the gasifier (mol%) are: CO: 55%, H 2 :36%、CO 2 : 9%;

[0116] Gasifier synthesis gas production: 4.26×10 6 Nm 3 / d;

[0117] Composition of coal gas produced by the carbonization unit (mol%): CO: 13%, H 2 :12.0%、CO 2 :30%、CH 4 :12.0%、C n H m :20%、N 2 : 13%;

[0118] Gas production of distillation unit: 2.8×10 4 Nm 3 / d;

[0119] Deep processing unit diesel, gasoline and other oil product output: 10.5t / d;

[0120] From the above indicators, it can be seen that when the gasification temperature is operated at 1400℃, CO and H 2 The contents of CO 2 The content of is reduced, resulting in an increase in the overall synthesis gas output. However, when the gasification temperature is 1400°C, a more stringent high temperature resistance requirement is imposed on the gasifier to avoid damage to the refractory materials in the gasifier due to excessively high temperature. The temperature of the outer wall of the gasifier increases from about 200°C to about 260°C compared with Example 1.

[0121] Comparative Example 1

[0122] The method is carried out with reference to Example 1, except that: the high-sodium coal is not coupled with oil shale for deep processing; in the process of preparing water-coal slurry with high-sodium coal, the oily wastewater generated by the treatment of oil shale semi-coke and shale oil in the deep processing unit is not introduced; the solid concentration of the water-coal slurry in this comparative example is the same as that of the water-coal-oil slurry in Example 1; the process conditions for gasification of water-coal slurry prepared with high-sodium coal are the same as those in Example 1.

[0123] The experimental results are as follows:

[0124] The main components of the syngas produced by the gasifier (mol%) are: CO: 50%, H 2 :31%、CO 2 : 19%;

[0125] Gasifier synthesis gas production: 3.96×10 6 Nm 3 / d;

[0126] When only high sodium coal is used as gasification raw material, the effective gas composition and output are lower than those after mixing with oil shale semi-coke, and no other by-products are produced. At the same time, direct use of water-coal slurry prepared with high sodium coal for gasification often leads to scaling problems. The fly ash was sampled and analyzed, and the results are shown in Table 5:

[0127] Table 5 Fly ash composition of high sodium coal gasification operation / wt%

[0128] <![CDATA[SiO 2 ]]> <![CDATA[Al 2 THE 3 ]]> <![CDATA[Fe 2 THE 3 ]]> CaO MgO <![CDATA[TiO 2 ]]> <![CDATA[SO 3 ]]> <![CDATA[K 2 The]]> <![CDATA[Na 2 The]]> <![CDATA[P 2 THE 3 ]]> 44.65 18.46 11.76 6.86 3.02 0.73 5.54 0.33 6.82 0.38

[0129] It can be seen from the above table that most of the potassium and sodium in the coal ash are enriched in the fly ash. Compared with Examples 1-3, the deposition and scaling of the fly ash are prone to occur, resulting in frequent scaling problems in the downstream pipelines, making the system operation unstable and the operation cycle short. The stable operation cycle is less than 20 days, and regular inspection and maintenance are required; while in the above embodiments of the present invention, the stable operation cycle is greater than 100 days.

[0130] It is easy to understand that the above embodiments are only examples for clear explanation and do not mean that the present invention is limited thereto. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the protection scope of the present invention.

Claims

1. A system for coupling deep processing of oil shale and high sodium coal, characterized in that: The system includes a drying and dehydration unit, a dry distillation unit, a deep processing unit, a water-kerosene slurry preparation unit and a gasification unit; The drying and dehydration unit is used to dry and dehydrate the crushed oil shale to obtain dried oil shale; The dry distillation unit is used to receive the dried oil shale and dry distill it to obtain coal gas, shale oil and oil shale semi-coke; The deep processing unit is used to separate oil from water and process the shale oil to obtain oily wastewater and oil products; The water-coal-oil slurry preparation unit is used to receive the high-sodium coal, the oil shale semi-coke and the oily wastewater and prepare the water-coal-oil slurry; The gasification unit is used to gasify the water-kerosene slurry and the gasification agent to obtain synthesis gas and gasified slag; The gasification unit and the dry distillation unit are connected via a synthesis gas output pipe, which is used to perform heat exchange between the synthesis gas obtained by the gasification unit and the dry distillation unit; The dry distillation unit and the drying and dehydration unit are connected via a gas output pipe, which is used to pass the gas obtained by the dry distillation unit as fuel into the drying and dehydration unit for combustion to provide heat.

2. The oil shale and high sodium coal coupled deep processing system according to claim 1 is characterized in that: It also includes a mixing unit for receiving the high-sodium coal and the oil shale semi-coke obtained by the distillation unit and pre-mixing the two; the water-coal-oil slurry preparation unit is connected to the mixing unit to receive the pre-mixed high-sodium coal and the oil shale semi-coke.

3. The oil shale and high sodium coal coupled deep processing system according to claim 1 or 2, characterized in that: It also includes a dust removal and purification unit, which is used to remove dust and purify the synthesis gas that has undergone heat exchange with the dry distillation unit to obtain purified synthesis gas.

4. The oil shale and high sodium coal coupled deep processing system according to claim 1 or 2, characterized in that: The synthesis gas obtained by the gasification unit undergoes heat exchange with the dry distillation unit in an indirect heat exchange manner.

5. The oil shale and high sodium coal coupled deep processing system according to claim 1 or 2, characterized in that: The invention also comprises a gasified slag processing unit, which is used for processing building materials with the gasified slag as raw material.

6. A process for coupling deep processing of oil shale and high-sodium coal using the oil shale and high-sodium coal coupling deep processing system according to any one of claims 1 to 5, characterized in that: The steps include: After the oil shale is crushed, it is sent to the drying and dehydration unit for drying and dehydration to obtain dried oil shale; the heat required by the drying and dehydration unit is the heat generated by the combustion of the coal gas obtained in the dry distillation unit; The dried oil shale is sent to the dry distillation unit for dry distillation to obtain coal gas, shale oil and oil shale semi-coke; the dry distillation unit obtains heat required for the dry distillation by heat exchange with the synthesis gas obtained from the gasification unit; the coal gas is output to the drying and dehydration unit through the coal gas output pipe for combustion to provide heat required for the drying and dehydration; The shale oil is sent to the deep processing unit for oil-water separation and processing to obtain oily wastewater and oil products; Prepare a water-kerosene slurry by using high sodium coal, the oil shale semi-coke and the oily wastewater in the water-kerosene slurry preparation unit; The water-kerosene slurry is sent to the gasification unit to undergo a gasification reaction with a gasifying agent to obtain synthesis gas and gasified slag; the synthesis gas obtained by the gasification unit is output through the synthesis gas output pipe and undergoes heat exchange with the dry distillation unit.

7. The process according to claim 6, characterized in that The high sodium coal and the oil shale semi-coke are pre-mixed in a mixing unit and then fed into the water-coal-oil slurry preparation unit; and / or, sending the synthesis gas that has completed the heat exchange in the dry distillation unit to a dust removal and purification unit for dust removal and purification to obtain purified synthesis gas; preferably, the purified synthesis gas is used as a synthetic raw material for producing chemicals; And / or, the gasified slag is fed into a gasified slag processing unit, and the gasified slag is used as a raw material for processing building materials.

8. The process according to claim 6 or 7, characterized in that The gasification unit performs the gasification reaction at a gasification temperature of 1200° C. to 1500° C. and a gasification pressure of 4.0 to 8.5 MPa, preferably a gasification pressure of 4.0 to 6.0 MPa.

9. The process according to claim 8, characterized in that The gasification temperature is 1250°C to 1350°C.

10. The process according to claim 6 or 7, characterized in that The moisture content of the dried oil shale is less than 6wt%, preferably less than 3wt%; And / or, the drying temperature of the drying and dehydration unit for the drying and dehydration is 100-200° C., preferably 105-120° C.; and / or, the dry distillation temperature in the dry distillation unit is 400-600° C., preferably 450-500° C.; and / or, in the dry distillation unit, the temperature of the synthesis gas after the heat exchange is 600° C. to 800° C.; And / or, in the deep processing unit, the oil product obtained includes diesel and / or gasoline; And / or, when preparing the water-coal-oil slurry, the ratio of the mass of the oil shale semi-coke used to the mass of the high-sodium coal used does not exceed 15:100; And / or, the solid content of the water-kerosene slurry is not less than 50 wt %, preferably 50-70 wt %, more preferably 60-65 wt %.

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