Crude benzene yield-increasing coal blending process and system under blending condition of high-sulfur coal and non-coking coal

Abstract

The invention relates to the technical field of coal chemical industry and coking processes, and discloses a crude benzene yield-increasing coal blending process and system under the condition of blending high-sulfur coal and non-coking coal, and the process comprises the following steps: mixing a first component comprising the high-sulfur coal and the non-coking coal, a second component of high-cohesiveness fat coal and a third component of prime coking coal; the comprehensive atom carbon hydrogen ratio of the mixed coal is controlled to be 1.0-1.5. And then loading into a top-loading coke oven for dry distillation, and controlling the central temperature at the final stage of coking to be 1030-1070 DEG C, so that the organic sulfur is fractured and converted into hydrogen sulfide, and the hydrogen sulfide is cracked to generate the benzene hydrocarbon. And finally, cooling the raw coke oven gas, removing hydrogen sulfide through pre-deep desulfurization, and washing to recover crude benzene. According to the method, the comprehensive atom carbon hydrogen ratio of the mixed coal is limited to be 1.0-1.5, and a specific pyrolysis temperature field is matched, so that sulfur-containing organic functional groups are effectively induced to be broken, and meanwhile, benzene ring fragments are inhibited from being condensed into macromolecular tar.

Description

Technical Field

[0001] This invention relates to the fields of coal chemical and coking technology, specifically to a coal blending process and system for increasing crude benzene production under the condition of blending high-sulfur coal and non-coking coal. Background Technology

[0002] Coking coal resources are becoming increasingly scarce, especially high-quality prime coking coal and fat coal, whose prices have remained high for a long time. For coking enterprises, minimizing raw material costs while ensuring the quality of metallurgical coke is crucial for survival. Meanwhile, crude benzene, a byproduct of coking, is an important chemical raw material, and its market value often exceeds that of coke itself. Therefore, introducing abundant and inexpensive high-sulfur coal or non-coking coal into production, and using technological means to efficiently convert its volatile matter into high-value-added crude benzene, is of great practical significance for improving the overall profitability and resource utilization efficiency of coking plants.

[0003] Existing coking coal blending technologies primarily rely on industrial analysis indicators of coal for regulation, focusing on the balance of dry ash-free volatile matter, caking index (G value), and maximum plastic layer thickness (Y value). By rationally blending prime coking coal with a certain proportion of lean coal or gas coal, coke with acceptable cold strength can be produced in a standard carbonization chamber. Current conventional processes can maintain relatively stable coking performance when processing standard coal types, and the accompanying chemical product recovery system can also separate tar and crude benzene through a wash oil absorption process when processing low-sulfur coal gas. The process flow is relatively mature, and the equipment is highly versatile.

[0004] However, this traditional coal blending method based on macroscopic indicators has significant limitations when dealing with low-quality coal. First, focusing solely on the total volatile matter while ignoring the atomic carbon-hydrogen ratio at the molecular level leads to excessive cracking of high-volatile coals during pyrolysis, generating low-value gaseous alkanes, or condensation into heavy tar, resulting in a low actual yield of crude benzene. Second, existing technologies lack a strong caking compensation mechanism when blending non-coking coals. If the blending amount is slightly large, the post-reaction strength (CSR) of the coke will drop sharply, resulting in only a very small proportion for blending and limited cost reduction. In addition, traditional processes often employ a process of washing benzene before desulfurization. When treating high-concentration hydrogen sulfide flue gas generated from high-sulfur coal, a large amount of hydrogen sulfide will enter the wash oil along with benzene hydrocarbons. This not only causes excessive sulfur content in the crude benzene product but also leads to rapid aging and failure of the wash oil, making it difficult to maintain long-term operation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a coal blending process and system for increasing crude benzene production under the condition of blending high-sulfur coal and non-coking coal. This addresses the technical problems of existing coking coal blending technologies, which cannot effectively balance the contradiction between the strength of coke after reaction and crude benzene yield when blending large amounts of inferior coal sources such as high-sulfur coal and non-coking coal, and the technical problems of excessive sulfur content in crude benzene products and aging and failure of wash oil due to the coexistence of high concentrations of hydrogen sulfide.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a coal blending process for increasing crude benzene production under the condition of blending high-sulfur coal and non-coking coal, adopting the following technical solution:

[0008] A coal blending process for increasing crude benzene production under blending conditions of high-sulfur coal and non-coking coal includes the following steps:

[0009] S1. The first component, the second component, and the third component are pulverized and mixed to prepare blended coal; the first component includes high-sulfur coal and non-coking coal, the second component includes highly caking coking coal, and the third component includes at least one of prime coking coal or 1 / 3 coking coal; and the overall atomic carbon-hydrogen ratio of the blended coal is controlled to be 1.0 to 1.5.

[0010] S2. The blended coal is loaded into the carbonization chamber of the top-loading coke oven and subjected to high-temperature dry distillation under air-isolated conditions. The temperature of the center of the carbonization chamber at the end of coking is controlled to be 1030°C to 1070°C, so that the sulfur-containing organic functional groups in the blended coal are broken down into hydrogen sulfide under the action of active hydrogen free radicals and decomposed into benzene hydrocarbons to obtain coke and raw coal gas.

[0011] S3. The raw coal gas is discharged and cooled, and then subjected to pre-desulfurization treatment to remove hydrogen sulfide. The desulfurized coal gas is then washed to recover crude benzene. The pre-desulfurization treatment is performed before the crude benzene washing and recovery process.

[0012] By adopting the above technical solution, this invention utilizes high-sulfur coal and non-coking coal as the raw material base rich in hydrogen or volatile matter, uses highly caking coking coal as a binder, and uses prime coking coal or 1 / 3 coking coal as the framework support to construct a three-component synergistic coal blending system. The principle of this invention lies in utilizing the regulatory effect of the comprehensive atomic carbon-hydrogen ratio on the distribution of pyrolysis products, specifically as follows:

[0013] First, the overall atomic carbon-hydrogen ratio of the blended coal is controlled between 1.0 and 1.5, and a pyrolysis temperature of 1030℃ to 1070℃ is used to ensure that the coal macromolecules release an appropriate concentration of active hydrogen radicals in the early stages of pyrolysis. This concentration satisfies the requirements of subsequent hydrogenation reactions while preventing excessive cracking due to excessive hydrogen content, which could lead to the generation of low-value gases such as methane.

[0014] Secondly, under the aforementioned environment of enriched active hydrogen free radicals, the thermally stable organic sulfur functional groups such as thiophene and sulfides in high-sulfur coal interact with active hydrogen, promoting the breakage of carbon-sulfur bonds and directionally converting organic sulfur into gaseous inorganic hydrogen sulfide. This process promotes the migration of sulfur from solid-phase coke and liquid-phase tar to the gas phase, thereby reducing the sulfur content of coke and liquid-phase products.

[0015] Meanwhile, an appropriate amount of active hydrogen radicals can stabilize benzene ring radical fragments generated during pyrolysis, inhibiting their condensation reaction to form large-molecule tar or asphalt, and suppressing their ring-opening cracking to form small-molecule alkanes. This selective stabilizing effect increases the proportion of carbon elements in volatiles converted into monocyclic aromatic hydrocarbons, i.e., crude benzene.

[0016] Finally, to address the high concentration of hydrogen sulfide generated from the pyrolysis of high-sulfur coal, a pre-desulfurization strategy is adopted to remove hydrogen sulfide before washing crude benzene. This prevents hydrogen sulfide from entering the wash oil and crude benzene product through physical dissolution or chemical adsorption in the benzene washing tower, thereby ensuring the purity of the crude benzene product and the circulation activity of the wash oil under the condition of high-sulfur coal blending.

[0017] In summary, this invention achieves the large-scale utilization of low-cost, low-quality coal and its transformation into high-value-added crude benzene products while ensuring the integrity of the coke skeleton structure.

[0018] Preferably, in step S1, the blended coal is made from raw materials comprising the following mass percentages: the first component is 15% to 25%; the second component is 15% to 30%; the third component is 45% to 70%; and the dry ash-free volatile matter of the blended coal is controlled at 28.0% to 32.0%, the comprehensive weighted caking index is not less than 75, and the maximum thickness of the comprehensive plastic layer is not less than 16.0 mm.

[0019] By adopting the above technical solution and limiting the proportion of each component and the rheological index of the blended coal, it is ensured that when low-quality coal is blended, the blended coal can generate sufficient colloidal liquid phase during the softening and melting stage to fill the gaps between the skeleton particles and wet the inert components, thus ensuring that the cold strength and hot strength of the final coke meet the metallurgical coke standard.

[0020] Preferably, the raw material characteristics of the first component, the second component, and the third component are as follows: the high-sulfur coal is a high-volatile bituminous coal with a dry basis total sulfur content of not less than 2.0%; the non-coking coal is one or a combination of long-flame coal, lean coal, or lignite; the highly caking coking coal is a strongly caking coal with a dry ash-free basis volatile content of 26.0% to 32.0%, a caking index greater than 85, and a maximum plastic layer thickness greater than 25.0 mm; the prime coking coal or 1 / 3 coking coal serves as the skeleton support component, and the caking index of each individual coal is not less than 75.

[0021] By adopting the above technical solutions, the physicochemical property boundaries of each coal component were clarified. Selecting highly caking coking coal as the second component effectively compensates for the insufficient caking properties of high-sulfur coal and non-coking coal; selecting high-volatile high-sulfur coal or non-coking coal provides a sufficient carbon and hydrogen source basis for the formation of crude benzene.

[0022] Preferably, the first component consists of high-sulfur coal and non-coking coal, and the mass ratio of high-sulfur coal to non-coking coal is 1.2 to 3.0:1; or, the first component is used after pretreatment, wherein the pretreatment includes pre-mixing and crushing high-sulfur coal and non-coking coal until the proportion of particles with a particle size of less than 3 mm reaches more than 85%.

[0023] By adopting the above technical solutions, controlling the ratio of high-sulfur coal to non-coking coal or carrying out fine crushing pretreatment, the dispersion uniformity of inferior coal components in blended coal can be improved, avoiding coke cracks or structural defects caused by the concentration of inert components in local areas, and further ensuring the uniformity of coke quality.

[0024] Preferably, in step S2, the specific process parameters for directional pyrolysis are: controlling the temperature of the machine-side flue to be 1280℃ to 1320℃, the temperature of the coke-side flue to be 1300℃ to 1340℃, and the coking time to be 19.0 to 23.0 hours; by controlling the overall atomic carbon-hydrogen ratio of the blended coal and the center temperature of the carbonization chamber at the end of coking, the mass ratio of benzene to tar in the pyrolysis products is maintained between 0.35 and 0.45.

[0025] By employing the above technical solution and utilizing a combination of temperature field control and C / H ratio regulation, the pyrolysis reaction was maintained within the kinetic range of benzene ring formation. The benzene to tar mass ratio was maintained between 0.35 and 0.45, indicating that the system suppressed the formation of heavy tar and achieved a directional conversion to light aromatics.

[0026] Preferably, in step S3, the pre-treatment deep desulfurization process employs a wet oxidation desulfurization process, using a desulfurization liquid containing cobalt phthalocyanine sulfonate catalyst to wash the raw coal gas; the pH value of the desulfurization liquid is controlled to be 8.5 to 9.0, and the regeneration tower pressure is 0.4 to 0.6 MPa; after the pre-treatment deep desulfurization process, the hydrogen sulfide content in the coal gas before entering the crude benzene washing and recovery process is controlled to be no higher than 200 mg / Nm³. 3 .

[0027] By adopting the above technical solution and utilizing the catalytic oxidation desulfurization process, the hydrogen sulfide content in raw coal gas can be reduced to below the safe threshold under specific pH and pressure conditions, thus avoiding the pollution of subsequent crude benzene and wash oil quality by hydrogen sulfide.

[0028] Preferably, in step S3, the specific method for washing the desulfurized coal gas to recover crude benzene is as follows: benzene hydrocarbons in the coal gas are absorbed countercurrently by wash oil in the benzene washing tower; the inlet gas temperature of the benzene washing tower is controlled at 25.0℃ to 27.0℃; the wash oil temperature is controlled to be 2.0℃ to 4.0℃ higher than the coal gas temperature; and the liquid-to-gas ratio of the wash oil circulation is controlled at 1.6 to 2.0 L / m³. 3 The wash oil is a high-temperature coal tar fraction with a distillation range of 230℃ to 300℃.

[0029] By adopting the above technical solution, utilizing the optimized washing temperature gradient and liquid-gas ratio, combined with washing oil of a specific distillation range, the absorption efficiency and selectivity of washing oil for benzene hydrocarbons are improved, power consumption is reduced, and the volatilization loss of light components in the washing oil is reduced.

[0030] Preferably, in step S1, the specific control parameters for the crushing and mixing are: controlling the mass ratio of particles with a diameter less than 3.0 mm in the blended coal after crushing to be 78.0% to 82.0%, and adjusting the moisture content of the blended coal to 8.5% to 9.5%.

[0031] By adopting the above technical solutions, the appropriate particle size distribution increases the contact area between coal particles, which is beneficial to the transfer and bonding of colloids; the appropriate moisture content ensures the bulk density of coal charging and the stability of operation.

[0032] Preferably, the process further includes a feedback adjustment step: detecting the yield of crude benzene in step S3 and the post-reaction strength of the coke obtained in step S2; when the crude benzene yield is less than 1.2%, increasing the proportion of long-flame coal in the first component while maintaining the overall atomic carbon-hydrogen ratio of 1.0 to 1.5; when the post-reaction strength of the coke is less than 60%, increasing the mass proportion of the second component in the blended coal.

[0033] By adopting the above technical solution, a dynamic coal blending correction mechanism based on product performance feedback was established. To address insufficient crude benzene yield, hydrogen-rich components were added to supplement the active hydrogen source; to address insufficient coke strength, high-caking components were added to strengthen the skeleton bonding, ensuring that the production process is always under optimal operating conditions.

[0034] Secondly, the present invention provides a crude benzene production-increasing coal blending system based on the above-mentioned process, using the following technical solution:

[0035] A crude benzene production enhancement coal blending system under blending conditions of high-sulfur coal and non-coking coal includes:

[0036] The coal quality characteristic detection unit is used to obtain data on the physicochemical properties and hydrocarbon content of a single type of coal.

[0037] The data processing and coal blending control unit is connected to the coal quality characteristic detection unit and is used to calculate the blending ratio of each component based on the physicochemical properties of the raw coal, the carbon and hydrogen content data, and the preset constraint that the comprehensive atomic carbon-hydrogen ratio is 1.0-1.5.

[0038] A precise batching and preparation unit is connected to the data processing and coal blending control unit and is used to prepare blended coal according to the blending ratio.

[0039] The top-loading coke oven reaction unit is used to perform directional pyrolysis of the blended coal and control the temperature at the end of coking to obtain coke and raw coal gas.

[0040] The raw coal gas condensation and separation unit is connected to the raw coal gas outlet of the top-charged coke oven reaction unit. It is used to cool the raw coal gas produced by the top-charged coke oven reaction unit and separate tar and ammonia water to obtain pre-cooled coal gas.

[0041] A pre-desulfurization unit is installed in the flow path after the raw coal gas is condensed and separated. It is used to desulfurize the initially cooled coal gas to remove hydrogen sulfide before crude benzene recovery, thereby obtaining desulfurized coal gas.

[0042] A crude benzene washing and recovery unit is located downstream of the pre-desulfurization unit and is used to recover crude benzene from the desulfurized coal gas.

[0043] The product feedback monitoring unit is connected to the top-loading coke oven reaction unit and the crude benzene washing and recovery unit, respectively, and is used to detect the post-reaction strength of the coke and the yield of the crude benzene, and transmit the post-reaction strength and the yield as feedback data to the data processing and coal blending control unit.

[0044] By adopting the above technical solution, the system integrates functional modules such as raw material detection, calculation, batching, reaction, purification, and feedback correction, realizing automated control of the coal blending process. The data processing and coal blending control unit can adjust the blending ratio in real time according to the fluctuation of raw coal quality, ensuring that the blended coal is always within the carbon-hydrogen ratio window; the series arrangement of the pre-desulfurization unit and the crude benzene washing and recovery unit ensures the low sulfur content of the crude benzene product; the product feedback monitoring unit realizes closed-loop control, improving the stability of system operation.

[0045] The crude benzene production enhancement coal blending process and system provided by this invention under the condition of blending high-sulfur coal and non-coking coal has the following beneficial effects:

[0046] This invention, by limiting the overall atomic carbon-hydrogen ratio of blended coal to the range of 1.0 to 1.5 and matching a specific pyrolysis temperature field, creates an atmosphere of suitable concentration of active hydrogen free radicals within the pyrolysis microenvironment. This effectively induces the breakage of sulfur-containing organic functional groups and inhibits the condensation of benzene ring fragments into macromolecular tar. Compared with the extensive mode of blending coal based solely on macroscopic volatile matter indicators in existing technologies, this scheme solves the problem that high-volatile, low-quality coal is prone to producing large amounts of tar or excessive cracking into low-carbon alkanes during pyrolysis. It achieves a significant increase in crude benzene yield and directional gas-phase migration of sulfur.

[0047] This invention constructs a ternary synergistic coal blending system comprising a first component of high-sulfur coal and non-coking coal, a second component of highly caking coking coal, and a third component of prime coking coal. Utilizing the abundant plastic mass generated by the highly caking component during the plastic coking stage, it fully fills the skeletal voids caused by the inert component, encapsulating low-quality coal particles. Addressing the shortcomings of existing technologies where blending non-coking coal often leads to a significant decline in the coke's coke strength (CSR) after reaction, this process, while absorbing low-cost, low-quality coal, ensures that the cold and hot strength indicators of the coke meet metallurgical coke standards, thus significantly reducing raw material costs.

[0048] This invention employs a process flow of deep desulfurization of raw coal gas coupled with crude benzene washing and recovery. Before the crude benzene absorption process, the hydrogen sulfide content in the coal gas is reduced to a safe low level, blocking the mass transfer path of inorganic sulfur to wash oil and crude benzene products in the benzene washing tower. Compared with the phenomenon that hydrogen sulfide is easily co-absorbed with benzene hydrocarbons in the existing conventional process, resulting in excessive sulfur content in crude benzene, this technical solution effectively eliminates the poisoning and aging of wash oil, improves the purity and added value of crude benzene products, and achieves long-term stable operation of the system under high sulfur feed conditions. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the system structure according to an embodiment of the present invention;

[0050] Figure 2 This is a graph showing the correlation between the overall atomic carbon-hydrogen ratio of the coal and the distribution of pyrolysis products and sulfur conversion rate in the test examples of this invention.

[0051] Figure 3 This is a comparison chart of the input-output distribution of raw material cost index and crude benzene yield for each embodiment and comparative example in the test examples of this invention.

[0052] Explanation of icon numbers:

[0053] 1. Coal quality characteristic detection unit; 2. Data processing and coal blending control unit; 3. Precision batching preparation unit; 4. Top-charged coke oven reaction unit; 5. Raw coal gas condensation and separation unit; 6. Pre-desulfurization unit; 7. Crude benzene washing and recovery unit; 8. Product feedback monitoring unit. Detailed Implementation

[0054] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0056] High-sulfur coal A is a high-volatile bituminous coal with a dry ash-free volatile content of 34.2% and a dry-basis total sulfur content of 2.6%. The pyrite sulfur content is 1.75%, the organic sulfur content is 0.85%, and the inorganic sulfur to organic sulfur mass ratio is approximately 2.06. Elemental analysis (dry ash-free basis) shows a carbon content of 80.5%, a hydrogen content of 5.2%, a nitrogen content of 1.3%, and an oxygen content of 10.4%, with a calculated atomic carbon-hydrogen ratio of 1.29.

[0057] High-sulfur coal B is a medium-to-high volatile bituminous coal. Its dry ash-free volatile matter content is 29.8%, and its dry-basis total sulfur content is 3.1%, of which the pyrite sulfur content is 2.2% and the organic sulfur content is 0.9%. Elemental analysis (dry ash-free basis) shows that the carbon content is 83.2% and the hydrogen content is 4.9%, and the calculated atomic carbon-hydrogen ratio is 1.41.

[0058] Lean coal A is a low-volatile non-coking coal with a dry ash-free volatile content of 14.5%, a caking index of 12, a maximum plastic layer thickness of 0 mm, and a dry basis total sulfur content of 0.5%. Elemental analysis (dry ash-free basis) shows a carbon content of 89.2% and a hydrogen content of 3.7%, with a calculated atomic carbon-hydrogen ratio of 2.01. It is mainly used to adjust the skeleton structure of blended coal.

[0059] Long-flame coal A is a high-volatile, weakly caking coal. Its dry ash-free volatile content is 37.5%, its caking index is 35, and its maximum plastic layer thickness is 5.0 mm. Elemental analysis (dry ash-free basis) shows that the carbon content is 78.6% and the hydrogen content is 5.4%. The calculated atomic carbon-hydrogen ratio is 1.21, which is used to provide volatiles and adjust the carbon-hydrogen ratio.

[0060] Lignite A is a low-coalification coal with a dry ash-free volatile matter content of 45.0% and no caking properties. Elemental analysis (dry ash-free) shows a carbon content of 68.5% and a hydrogen content of 6.2%, with a calculated atomic carbon-to-hydrogen ratio of 0.92. It is rich in aliphatic chain structures.

[0061] Highly caking coking coal A, as an active binder, has a dry ash-free volatile matter content of 28.5%, a caking index of 92, a maximum plastic layer thickness of 27.5 mm, a dry basis total sulfur content of 0.7%, and a maximum vitrinite reflectance of 1.05%. Elemental analysis shows that the carbon content is 85.5% and the hydrogen content is 5.3%.

[0062] High-caking coking coal B has a dry ash-free volatile matter content of 31.0%, a caking index of 88, a maximum plastic layer thickness of 26.0 mm, and a dry basis total sulfur content of 0.8%. Elemental analysis shows that the carbon content is 84.2% and the hydrogen content is 5.5%.

[0063] Prime coking coal A, as the backbone component, has a dry ash-free volatile matter content of 21.5%, a caking index of 82, a maximum plastic layer thickness of 18.5 mm, and a dry basis total sulfur content of 0.6%. Elemental analysis shows that the carbon content is 87.5% and the hydrogen content is 4.8%.

[0064] 1 / 3 coking coal A, as a basic skeleton coal, has a dry ash-free volatile matter content of 33.0%, a caking index of 78, a maximum plastic layer thickness of 16.5 mm, and a dry basis total sulfur content of 0.55%. Elemental analysis shows that the carbon content is 83.5% and the hydrogen content is 5.4%.

[0065] Wash oil is a high-temperature coal tar fraction, commercially available, with a main distillation range of 230℃ to 300℃ and a density (at 20℃) of 1.04 g / cm³. 3 Up to 1.06 g / cm 3 It contains less than 10% naphthalene and is used for the washing and recovery of crude benzene.

[0066] The main component of PDS desulfurization catalyst is dinuclear cobalt phthalocyanine sulfonate, which is commercially available. It appears as a blue-black powder with an effective active ingredient content of more than 90%. It has good water solubility and is used in the pre-wet oxidation desulfurization process of raw coal gas.

[0067] See Figure 1 , Figure 1 This is a schematic diagram of a crude benzene production-increasing coal blending system under blending conditions of high-sulfur coal and non-coking coal according to an embodiment of the present invention. The crude benzene production-increasing coal blending system provided by this embodiment of the present invention may include: a coal quality characteristic detection unit 1, a data processing and coal blending control unit 2, a precise batching preparation unit 3, a top-charged coke oven reaction unit 4, a raw coal gas condensation and separation unit 5, a pre-desulfurization deep desulfurization unit 6, a crude benzene washing and recovery unit 7, and a product feedback monitoring unit 8.

[0068] The coal quality characteristic detection unit 1 is specifically equipped with a fully automatic industrial analyzer, an elemental analyzer, and a plastic layer measuring instrument. It is used to perform physicochemical property analysis on basic coal types, obtain data on dry ash-free volatile matter, dry basis total sulfur content, sulfur speciation distribution, dry ash-free carbon content, dry ash-free hydrogen content, caking index, and maximum plastic layer thickness of a single coal type, and summarize the above data to generate coal quality physicochemical data.

[0069] The data processing and coal blending control unit 2, specifically an industrial control computer or DCS control system equipped with industrial control software, is connected to the coal quality characteristic detection unit 1 via signal transmission. The data processing and coal blending control unit 2 internally stores a linear programming algorithm model (i.e., a coal blending model) and preset constraints on the carbon-hydrogen ratio and volatile matter content. The linear programming algorithm model uses the lowest blending coal cost or the highest crude benzene yield as the objective function, with the comprehensive atomic carbon-hydrogen ratio (1.0-1.5), ash content, sulfur content, and caking index as constraint variables. It is iteratively solved using the simplex method or interior point method, and is used to calculate and generate the blending instructions for each type of coal based on the input coal physicochemical data and subsequent feedback correction signals.

[0070] The precision batching preparation unit 3 is electrically connected to the data processing and coal blending control unit 2, and specifically includes a quantitative feeding hopper (equipped with an electronic belt scale at the bottom) and a crushing and mixing device (including a hammer crusher and a twin-shaft mixer). The precision batching preparation unit 3 is used to perform feeding, crushing and uniform mixing operations of each type of coal according to the ratio instructions to prepare a blended coal that meets the requirements.

[0071] The top-charged coke oven reaction unit 4, located downstream of the precision batching preparation unit 3, includes a carbonization chamber and a combustion chamber (arranged alternately). The top-charged coke oven reaction unit 4 is equipped with a temperature control loop (including vertical flue thermocouples and gas flow regulating valves) to control the heating rate of the carbonization chamber during the coking process and the central temperature at the end of coking, ensuring that the blended coal undergoes a directional pyrolysis reaction within the carbonization chamber. After the reaction is completed, the top-charged coke oven reaction unit 4 produces raw coal gas and coke, while simultaneously collecting the physical properties of the coke to generate coke strength data.

[0072] The raw coal gas condensation and separation unit 5 is connected to the riser pipe at the top of the top-loading coke oven reaction unit 4, and specifically includes a bridge pipe, a gas collecting pipe, a primary cooler, and a mechanized clarification tank. The bridge pipe and gas collecting pipe are used to discharge high-temperature raw coal gas and spray ammonia water for preliminary cooling; the primary cooler is used to further reduce the temperature of the raw coal gas to 22-25℃ through indirect heat exchange; the mechanized clarification tank is used to receive condensate and separate tar and ammonia water. The raw coal gas condensation and separation unit 5 uses the above equipment to condense and separate tar mist and ammonia water in the raw coal gas, thereby outputting pre-cooled coal gas.

[0073] The pre-desulfurization unit 6 is located at the gas outlet of the raw coal gas condensation and separation unit 5, and specifically includes a desulfurization tower and a matching regeneration tower. The desulfurization tower adopts a packed or empty-tower spray structure, utilizing a desulfurization liquid containing a catalyst to countercurrently contact the initially cooled coal gas to remove inorganic hydrogen sulfide components. The regeneration tower is used to oxidize and regenerate the rich liquid using compressed air. After treatment, the pre-desulfurization unit 6 outputs desulfurized coal gas with a qualified sulfur content.

[0074] The crude benzene washing and recovery unit 7 is located at the gas outlet of the pre-desulfurization unit 6. Specifically, it includes a benzene washing tower, a rich oil heat exchanger, a tubular heater, and a benzene removal tower connected in sequence, along with a matching wash oil circulation flow controller. The benzene washing tower absorbs benzene hydrocarbons from the desulfurized coal gas using lean wash oil, and the washed coal gas is discharged as tail gas (which can be reused for combustion chamber heating). The benzene removal tower distills and separates the benzene-absorbed rich oil to obtain crude benzene product and generate crude benzene yield data. The lean oil separated from the wash oil circulation is cooled and returned to the benzene washing tower for reuse, forming a tail gas / wash oil circulation path together with the tail gas emission.

[0075] The product feedback monitoring unit 8 is connected to both the top-charged coke oven reaction unit 4 and the crude benzene washing and recovery unit 7. Specifically, the product feedback monitoring unit 8 includes a coke rotary drum test machine and a crude benzene metering tank, used to receive coke strength data and crude benzene yield data. The product feedback monitoring unit 8 analyzes and compares the above data, generates a correction feedback signal, and transmits it back to the data processing and coal blending control unit 2. This signal serves as a correction coefficient to iteratively correct the constraints in the linear programming algorithm model.

[0076] Preparation Example 1:

[0077] This preparation example provides a blended coal a for increasing crude benzene production, comprising the following steps:

[0078] (1) Weigh each type of coal raw material accurately according to the mass percentage: high-sulfur coal A 10.0%, long-flame coal A 8.0%, high-caking fat coal A 25.0%, prime coking coal A 22.0%, and 1 / 3 coking coal A 35.0%. Among them, high-sulfur coal A and long-flame coal A constitute the first component, high-caking fat coal A is the second component, and prime coking coal A and 1 / 3 coking coal A constitute the third component.

[0079] (2) Each of the above-mentioned single coal types is fed into a crusher for crushing, and the mass ratio of particles with a diameter of less than 3.0 mm in the crushed coal is controlled to be 80.0%.

[0080] (3) The crushed coal is fed into a mixer for uniform mixing, and water is sprayed during the process to control the moisture content of the blended coal to 9.0%.

[0081] (4) After testing and calculation, the dry ash-free volatile matter of the obtained blended coal a is 29.8%, the comprehensive atomic carbon-hydrogen ratio is 1.34, the comprehensive weighted caking index is 82, and the comprehensive maximum thickness of the plastic layer is 21.0 mm. All indicators are in the center of the preferred range.

[0082] Preparation Example 2:

[0083] This preparation example provides a blended coal b for increasing crude benzene production, comprising the following steps:

[0084] (1) Weigh each type of coal raw material accurately according to the mass percentage: high-sulfur coal B 15.0%, lean coal A 5.0%, high-caking fat coal B 25.0%, prime coking coal A 20.0%, and 1 / 3 coking coal A 35.0%. Among them, high-sulfur coal B and lean coal A constitute the first component, high-caking fat coal B is the second component, and prime coking coal A and 1 / 3 coking coal A constitute the third component.

[0085] (2) Each of the above-mentioned single coal types is fed into a crusher for crushing, and the mass ratio of particles with a diameter of less than 3.0 mm in the crushed coal is controlled to be 78.0%.

[0086] (3) The crushed coal is fed into a mixer for uniform mixing, and water is sprayed during the process to control the moisture content of the blended coal to 8.5%.

[0087] (4) According to the test and calculation, the dry ash-free volatile matter of the obtained blended coal b is 28.8%, the comprehensive atomic carbon-hydrogen ratio is 1.37, the comprehensive weighted caking index is 79, and the comprehensive maximum thickness of the plastic layer is 18.5 mm, which meets the requirements of low volatile matter boundary of process parameters and bottoming out of coke quality.

[0088] Preparation Example 3:

[0089] This preparation example provides a blended coal c for increasing crude benzene production, comprising the following steps:

[0090] (1) Weigh each type of coal raw material accurately according to the mass percentage: high-sulfur coal A 15.0%, long-flame coal A 5.0%, high-caking fat coal A 20.0%, prime coking coal A 10.0%, and 1 / 3 coking coal A 50.0%. Among them, high-sulfur coal A and long-flame coal A constitute the first component, high-caking fat coal A is the second component, and prime coking coal A and 1 / 3 coking coal A constitute the third component.

[0091] (2) Each of the above-mentioned single coal types is fed into a crusher for crushing, and the mass ratio of particles with a diameter of less than 3.0 mm in the crushed coal is controlled to be 82.0%.

[0092] (3) The crushed coal is fed into a mixer for uniform mixing, and water is sprayed during the process to control the moisture content of the blended coal to 9.5%.

[0093] (4) According to the test and calculation, the dry ash-free volatile matter of the obtained blended coal c is 31.4%, the comprehensive atomic carbon-hydrogen ratio is 1.31, the comprehensive weighted caking index is 77, and the comprehensive maximum thickness of the plastic layer is 17.5 mm. It is located at the high volatile matter boundary of the process parameters, and still maintains qualified rheological properties under the maximum amount of inferior coal blending.

[0094] Example 1:

[0095] This embodiment provides a crude benzene production enhancement coal blending process using high-sulfur coal and non-coking coal, employing the blended coal a from Preparation Example 1 as raw material, and includes the following steps:

[0096] (1) In the coal loading and sealing step, the blended coal a obtained in Preparation Example 1 is loaded into the carbonization chamber through the coal loading car of the top-loading coke oven. After leveling the coal, the furnace door and the riser pipe are sealed to maintain a slight positive pressure of 100 Pa in the carbonization chamber.

[0097] (2) In the directional pyrolysis control step, a temperature control strategy matching the carbon-hydrogen ratio (C / H=1.34) of the blended coal a is implemented. The temperature of the machine-side flue is controlled at 1300℃, and the temperature of the coke-side flue is controlled at 1320℃; the temperature of the center of the carbonization chamber at the end of coking is controlled at 1050℃, and the coking time is 21.0h. Under this temperature field, the active hydrogen free radicals generated by the blended coal induce the breakage of sulfur-containing organic functional groups to generate hydrogen sulfide.

[0098] (3) In the raw coal gas extraction and primary cooling step, the raw coal gas generated by pyrolysis is extracted through the riser pipe, and ammonia water is sprayed at the bridge pipe to cool it to 82°C. Then it enters the primary cooler to further cool it to 22°C, and the tar and ammonia water are separated.

[0099] (4) In the pre-desulfurization step, the initially cooled raw coal gas is fed into a wet oxidation desulfurization tower and washed with a desulfurization liquid containing PDS catalyst. The pH value of the desulfurization liquid is controlled at 8.8, and the pressure of the regeneration tower is controlled at 0.5 MPa. The H2S content in the coal gas before entering the crude benzene recovery unit after desulfurization is measured to be 150 mg / Nm³. 3 .

[0100] (5) In the crude benzene washing and recovery step, the desulfurized coal gas is sent to the benzene washing tower. The coal gas temperature is controlled at 26.0℃ and the lean oil temperature is controlled at 29.0℃ (temperature difference 3.0℃); the liquid-to-gas ratio of the washing oil circulation is set at 1.8L / m³. 3 .

[0101] (6) In the rich oil debenzene removal and product acquisition step, the rich oil that has absorbed benzene hydrocarbons is preheated and sent to a tubular heater. It is heated to 180°C and then enters the debenzene removal tower for distillation. The top temperature of the debenzene removal tower is controlled at 92°C. The superheated steam consumption is 3.5 times the crude benzene production. The crude benzene product is obtained by condensation and separation.

[0102] Example 2:

[0103] This embodiment provides a coal blending process that focuses on a low-temperature, long-term pyrolysis mode, using the blended coal b from Preparation Example 2 as raw material, and includes the following steps:

[0104] (1) In the coal loading and sealing step, the blended coal b obtained in Preparation Example 2 is loaded into the carbonization chamber of the top-loading coke oven and the slight positive pressure in the carbonization chamber is maintained at 50 Pa.

[0105] (2) In the directional pyrolysis control step, a temperature control strategy adapted to low volatile distribution coal b is implemented. The temperature of the machine-side flue is controlled at 1280℃ and the temperature of the coke-side flue is controlled at 1300℃; the temperature of the center of the carbonization chamber at the end of coking is controlled at 1030℃, and the coking time is extended to 23.0h to ensure that the organic matter is fully decomposed and secondary thermal polymerization is inhibited at a lower temperature.

[0106] (3) In the raw coal gas extraction and primary cooling steps, after the raw coal gas is extracted, it is cooled to 80°C by ammonia water spraying and then cooled to 21°C in the primary cooler.

[0107] (4) In the pre-desulfurization step, the initially cooled raw coal gas is fed into the desulfurization tower. The pH value of the desulfurization liquid is controlled at 8.5, and the pressure of the regeneration tower is controlled at 0.4 MPa. The H2S content in the desulfurized coal gas is measured to be 180 mg / Nm³. 3 .

[0108] (5) In the crude benzene washing and recovery step, the inlet gas temperature of the benzene washing tower is controlled at 25.0℃, and the lean oil temperature is controlled at 27.0℃ (temperature difference 2.0℃); the liquid-to-gas ratio of the washing oil circulation is set at 1.6L / m 3 To reduce power consumption.

[0109] (6) In the rich oil benzene removal and product acquisition step, the rich oil is heated to 175°C in a tubular heater and enters the benzene removal tower. The top temperature of the benzene removal tower is controlled at 90°C and the superheated steam consumption is 3.0 times the crude benzene production. The crude benzene product is obtained by condensation and separation.

[0110] Example 3:

[0111] This embodiment provides a coal blending process that focuses on a high-temperature, short-time pyrolysis mode, using the blended coal c from Preparation Example 3 as raw material, and includes the following steps:

[0112] (1) In the coal loading and sealing step, the blended coal c obtained in Preparation Example 3 is loaded into the carbonization chamber of the top-loading coke oven, and the slight positive pressure in the carbonization chamber is maintained at 150 Pa.

[0113] (2) In the directional pyrolysis control step, an enhanced temperature control strategy adapted to high volatile coal C is implemented. The temperature of the machine-side flue is controlled at 1320℃ and the temperature of the coke-side flue is controlled at 1340℃; the temperature of the center of the carbonization chamber at the end of coking is controlled at 1070℃, shortening the coking time to 19.0h, and using high-temperature rapid pyrolysis to promote the gasification efficiency of high volatile coal.

[0114] (3) In the raw coal gas extraction and primary cooling steps, after the raw coal gas is extracted, it is cooled to 85°C by ammonia water spraying and then cooled to 23°C in the primary cooler.

[0115] (4) In the pre-desulfurization step, the desulfurization operation was intensified to address the high sulfur load of the blended coal c. The pH value of the desulfurization liquid was controlled at 9.0, and the pressure of the regeneration tower was controlled at 0.6 MPa. The H2S content in the desulfurized gas was measured to be 195 mg / Nm³. 3 This meets the requirements for entering the benzene washing tower.

[0116] (5) In the crude benzene washing and recovery step, control the inlet gas temperature of the benzene washing tower to 27.0℃ and the lean oil temperature to 31.0℃ (temperature difference 4.0℃); increase the liquid-to-gas ratio of the washing oil circulation to 2.0L / m³. 3 This is to cope with the high concentration of benzene hydrocarbon gas generated per unit time and prevent the wash oil from becoming saturated.

[0117] (6) In the rich oil benzene removal and product acquisition step, the rich oil is heated to 185°C in a tubular heater and enters the benzene removal tower. The top temperature of the benzene removal tower is controlled at 95°C. The superheated steam consumption is 4.0 times the crude benzene production. The crude benzene product is obtained by condensation and separation.

[0118] Example 4:

[0119] This embodiment provides a process optimization mode for high-sulfur coal blending conditions, also using the blended coal a from Preparation Example 1 as raw material, including the following steps:

[0120] (1) In the coal loading and sealing steps, the operation is the same as in Example 1, and the slight positive pressure in the carbonization chamber is maintained at 120 Pa.

[0121] (2) In the directional pyrolysis control step, the temperature of the center of the carbonization chamber at the end of the coking period is controlled at 1060℃ and the coking time is 20.0h.

[0122] (3) In the raw coal gas extraction and primary cooling step, the raw coal gas is cooled to 83°C and then enters the primary cooler to be cooled to 22.5°C.

[0123] (4) In the pre-desulfurization stage, the pH of the desulfurization solution is controlled at 8.9, and the pressure of the regeneration tower is controlled at 0.55 MPa. The H2S content in the desulfurized gas is 160 mg / Nm³. 3 .

[0124] (5) In the crude benzene washing and recovery step, the inlet gas temperature of the benzene washing tower is controlled at 26.5℃, and the lean oil temperature is controlled at 30.0℃ (temperature difference 3.5℃); the liquid-to-gas ratio of the washing oil circulation is set at 1.9L / m³. 3 .

[0125] (6) In the rich oil benzene removal and product acquisition step, the rich oil is heated to 182°C and enters the benzene removal tower. The top temperature of the benzene removal tower is controlled at 93°C. The superheated steam consumption is 3.8 times the crude benzene production, and crude benzene product is obtained.

[0126] Comparative Example 1:

[0127] Compared with Example 1, the difference is that high-sulfur coal A and long-flame coal A were not added to the blended coal. Instead, 1 / 3 of the mass of coking coal A was used to replace them. The other raw material ratios and process steps are the same.

[0128] Comparative Example 2:

[0129] Compared with Example 1, the difference is that the raw material ratio of the blended coal was adjusted, the long-flame coal A that can provide high hydrogen content was removed, and the proportion of lean coal A was increased, so that the overall atomic carbon-hydrogen ratio of the blended coal is 1.65. The remaining process steps are the same.

[0130] Comparative Example 3:

[0131] Compared with Example 1, the difference is that the raw material ratio of the blended coal was adjusted, lignite A was used to replace high-sulfur coal A and long-flame coal A, and the proportion of coking coal was increased by 1 / 3, so that the overall atomic carbon-hydrogen ratio of the blended coal was reduced to 0.90. The remaining process steps are the same.

[0132] Comparative Example 4:

[0133] Compared with Example 1, the difference is that the highly caking coking coal A in the second component is replaced by 1 / 3 coking coal A of equal mass, which reduces the overall weighted caking index of the blended coal to 65 and the maximum thickness of the overall plastic layer to 13.0 mm. The other raw material ratios and process steps are the same.

[0134] Comparative Example 5:

[0135] Compared with Example 1, the difference is that the process sequence of raw coal gas purification has been changed, and the pre-desulfurization unit is set after the crude benzene washing and recovery unit, while the other raw material ratios and process parameters are the same.

[0136] Comparative Example 6:

[0137] Compared with Example 1, the difference is that the heating regime of the top-loading coke oven reaction unit was changed, and the center temperature of the carbonization chamber at the end of coking was controlled at 1150°C. The other raw material ratios and process steps are the same.

[0138] Test Example 1:

[0139] This test case verifies the effect of the overall atomic carbon-hydrogen ratio (C / H) of blended coal on the sulfur speciation pathway and the distribution of gaseous and liquid phase products during pyrolysis. The blended coals obtained from Preparation Examples 1, 2, and 3 were used as the experimental group, while the blended coals obtained from Comparative Examples 2 and 3 were used as the control group. The experimental steps are as follows:

[0140] Step (1) Accurately weigh 10.0g of each group of crushed coal samples, place them in a quartz boat, and push them into the constant temperature zone of the micro fixed-bed quartz tube pyrolysis furnace.

[0141] Step (2) introduce high-purity nitrogen gas at a flow rate of 100 mL / min as a carrier gas to remove air from the system and maintain an inert atmosphere for the pyrolysis process.

[0142] Step (3) The furnace temperature is raised from room temperature to 1050℃ at a heating rate of 5℃ / min and kept constant for 30 minutes to simulate the heating process of a top-loading coke oven.

[0143] Step (4) The gas generated by pyrolysis is condensed by a condenser tube. The non-condensable gas is introduced into a flame photometric detector (FPD) to monitor the release peak intensity of H2S gas in real time. The total amount of H2S released is calculated by integration and the gas phase sulfur conversion rate is calculated. The liquid phase product collected by the condenser tube is extracted with carbon disulfide and the content of benzene series compounds and tar heavy components is determined by gas chromatography-mass spectrometry (GC-MS). The benzene / tar mass ratio is calculated, and the residual concentration of thiophene and organic sulfides in the liquid phase product is detected at the same time.

[0144] The experimental data are shown in Table 1.

[0145] Table 1: Test data on the distribution of pyrolysis products and sulfur migration characteristics of different blended coals

[0146] Experiment number Overall atomic C / H ratio Volatile matter Vdaf (%) <![CDATA[H2S conversion rate (%)]]> Crude benzene yield (converted %) Tar yield (converted %) Benzene / Tar Ratio (B / T) Liquid phase organic sulfur residue (mg / kg) Preparation Example 1 1.26 30.2 86.42 1.43 3.55 0.403 425.3 Preparation Example 2 1.05 28.1 82.15 1.31 3.21 0.408 512.6 Preparation Example 3 1.48 31.8 84.37 1.52 3.92 0.388 489.1 Comparative Example 2 1.65 29.5 63.28 0.96 4.88 0.197 1856.4 Comparative Example 3 0.90 30.6 78.54 0.82 2.15 0.381 623.7

[0147] Based on the test data in Table 1 and Figure 2 The correlation curves shown indicate that when the C / H ratio of the blended coal is controlled within the range of 1.0-1.5 (Preparation Examples 1-3), the H2S conversion rate is 82%-86%, and the residual organic sulfur in the liquid phase is 425-512 mg / kg. When the C / H ratio increases to 1.65 (Comparative Example 2), the H2S conversion rate decreases to 63.28%, and the residual organic sulfur in the liquid phase increases to 1856.4 mg / kg. The data and curve trends indicate that within the pyrolysis temperature range of 1050℃, a specific range of atomic carbon-hydrogen ratios can provide the active hydrogen radicals required to induce the breakage of sulfur-containing organic functional groups, promoting the conversion of organic sulfur to inorganic sulfur (H2S).

[0148] Regarding product distribution, such as Figure 2 As shown, the benzene / tar ratio (B / T) of Preparation Examples 1-3 remained at a high level (0.38-0.41), with crude benzene yields of 1.31%-1.52%. In Comparative Example 2 (C / H=1.65), the benzene / tar ratio significantly decreased to 0.197; the crude benzene yield of Comparative Example 3 (C / H=0.90) was only 0.82%. The results indicate that an excessively high C / H ratio leads to the condensation reaction of aromatic hydrocarbon precursors to form large molecular weight tar, while an excessively low C / H ratio leads to excessive cracking to form gaseous alkanes. Limiting the overall atomic C-H ratio of the blended coal to the range of 1.0-1.5 is beneficial for balancing cracking and condensation reactions and improving the selectivity of light aromatics.

[0149] Test Example 2:

[0150] This test case verifies the combined effects of each example and comparative example on coke quality, crude benzene yield, and raw material cost under actual coking process conditions. The experimental subjects are the process products of Examples 1 to 4 and Comparative Examples 1 to 6. The experimental steps are as follows:

[0151] Step (1) Take the blended coal set in each example and comparative example respectively, and conduct coking experiments in a 400kg test coke oven equipped with a crude benzene recovery system. Perform the operation according to the process parameters (temperature, coking time, desulfurization sequence, etc.) set in each example.

[0152] Step (2) Collect the crude benzene produced in a single furnace, weigh it and calculate its percentage of the dry coal mass fed into the furnace; determine the total sulfur content in the crude benzene product using the microcoulometric method.

[0153] Step (3) After the coke matures, push the coke to extinguish the fire and take samples to determine the crushing strength M40 and abrasion resistance M10 of the coke according to GB / T 2006 standard; determine the coke reactivity index (CRI) and coke strength after reaction (CSR) according to GB / T 4000 standard.

[0154] Step (4) Based on the coal blending cost of Comparative Example 1, calculate the relative raw material cost index of each experimental group according to the market price of each type of coal.

[0155] The experimental data are shown in Table 2.

[0156] Table 2: Summary of Comprehensive Test Data on Coke Quality, Crude Benzene Yield, and Economic Indicators

[0157] Experiment number Crude benzene yield / % Crude benzene total sulfur / % Coke M40 / % Coke M10 / % Coke CSR / % Coke CRI / % Raw material cost index Example 1 1.38 0.035 86.4 6.2 63.5 26.4 0.86 Example 2 1.29 0.032 87.1 5.9 64.8 25.1 0.84 Example 3 1.45 0.041 85.2 6.5 61.2 28.3 0.81 Example 4 1.41 0.036 86.0 6.3 62.9 26.8 0.86 Comparative Example 1 0.95 0.021 89.5 5.2 69.5 21.5 1.00 Comparative Example 2 0.98 0.028 87.6 5.8 65.4 24.8 0.92 Comparative Example 3 0.85 0.039 82.3 7.8 55.6 32.1 0.83 Comparative Example 4 1.36 0.045 74.5 9.4 45.2 41.5 0.79 Comparative Example 5 1.39 0.168 86.3 6.2 63.4 26.5 0.86 Comparative Example 6 1.05 0.038 84.8 6.6 60.5 29.2 0.86

[0158] Based on the test data in Table 2 and Figure 3The input-output distribution map shown indicates that Examples 1 to 4 are concentrated in the advantageous region of low cost and high yield. Specifically, in this example, by controlling the C / H ratio within the range of 1.0-1.5, the crude benzene yield was increased to 1.29%-1.45%, which is better than the 0.95% of Comparative Example 1 (all high-quality coal); the raw material cost index was 0.81-0.86, which is lower than that of Comparative Example 1. Comparative Example 2, due to the excessive addition of lean coal resulting in a high C / H ratio, had a crude benzene yield of only 0.98%, indicating that simply blending low-quality coal while ignoring the C / H ratio window cannot effectively improve the crude benzene yield.

[0159] Regarding coke quality, the coke CSR in Examples 1-4 remained between 61.2% and 64.8%. In Comparative Example 4, the second component was removed, and the coke CSR decreased to 45.2%, indicating that the high-caking component in the three-component blend plays a necessary role in maintaining the integrity of the skeletal structure. The results of these examples confirm that this coal blending process and system can reduce raw material costs while simultaneously achieving coke quality standards and increasing crude benzene production.

[0160] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A coal blending process for increasing crude benzene production under the condition of blending high-sulfur coal and non-coking coal, characterized in that, include: S1. The first component, the second component, and the third component are crushed and mixed to prepare blended coal; The first component includes high-sulfur coal and non-coking coal, the second component includes highly caking coking coal, and the third component includes prime coking coal or 1 / 3 coking coal; and the overall atomic carbon-hydrogen ratio of the blended coal is controlled to be 1.0-1.

5. S2. The blended coal is loaded into the carbonization chamber of the top-loading coke oven and subjected to high-temperature dry distillation under air-isolated conditions. The temperature of the center of the carbonization chamber at the end of coking is controlled at 1030℃-1070℃ so that the sulfur-containing organic functional groups in the blended coal are broken down into hydrogen sulfide under the action of active hydrogen free radicals and decomposed into benzene hydrocarbons to obtain coke and raw coal gas. S3. The raw coal gas is discharged and cooled, and then subjected to pre-desulfurization treatment to remove hydrogen sulfide. The desulfurized coal gas is then washed to recover crude benzene. The pre-desulfurization treatment is performed before the crude benzene washing and recovery process.

2. The crude benzene production enhancement coal blending process under the blending conditions of high-sulfur coal and non-coking coal according to claim 1, characterized in that, In step S1, the blended coal is made from raw materials comprising the following mass percentages: The mass percentage of the first component is 15%-25%; The second component has a mass percentage of 15%-30%; The third component accounts for 45%-70% of the mass. Furthermore, the dry ash-free volatile matter content of the blended coal is controlled at 28.0%-32.0%, the comprehensive weighted caking index is ≥75, and the maximum thickness of the comprehensive plastic layer is ≥16.0mm.

3. The crude benzene production-increasing coal blending process under the blending conditions of high-sulfur coal and non-coking coal according to claim 1, characterized in that, The raw material characteristics of the first component, the second component, and the third component are as follows: The high-sulfur coal is a high-volatile bituminous coal with a dry basis total sulfur content of ≥2.0%; The non-coking coal is one or a combination of long-flame coal, lean coal or lignite; The highly caking coking coal is a strongly caking coal with a dry ash-free volatile matter content of 26.0%-32.0%, a caking index > 85, and a maximum plastic layer thickness > 25.0 mm. The primary coking coal or 1 / 3 coking coal serves as the skeleton support component, wherein the caking index of each type of coal is ≥75.

4. The crude benzene production enhancement coal blending process under the blending conditions of high-sulfur coal and non-coking coal according to claim 1, characterized in that, The first component consists of high-sulfur coal and non-coking coal, and the mass ratio of high-sulfur coal to non-coking coal is 1.2-3.0:1; Alternatively, the first component may be used after pretreatment, wherein the pretreatment includes pre-mixing and crushing high-sulfur coal and non-coking coal until the proportion of particles with a diameter of less than 3 mm reaches more than 85%.

5. The crude benzene production enhancement coal blending process under the blending conditions of high-sulfur coal and non-coking coal according to claim 1, characterized in that, In step S2, the specific process parameters for directional pyrolysis are as follows: the temperature of the machine-side flue is controlled at 1280℃-1320℃, the temperature of the coke-side flue is controlled at 1300℃-1340℃, and the coking time is 19.0-23.0 hours. By controlling the overall atomic carbon-hydrogen ratio of the blended coal and the center temperature of the carbonization chamber at the end of coking, the mass ratio of benzene to tar in the pyrolysis products is maintained between 0.35 and 0.

45.

6. The crude benzene production-increasing coal blending process under the blending conditions of high-sulfur coal and non-coking coal according to claim 1, characterized in that, In step S3, the pre-desulfurization treatment adopts a wet oxidation desulfurization process, which uses a desulfurization liquid containing cobalt phthalocyanine sulfonate catalyst to wash the raw coal gas. The pH of the desulfurization solution should be controlled at 8.5-9.0, and the pressure of the regeneration tower should be 0.4-0.6 MPa. After pre-treatment for deep desulfurization, the hydrogen sulfide content in the coal gas before entering the crude benzene washing and recovery process is controlled at ≤200mg / Nm³. 3 .

7. The crude benzene production enhancement coal blending process under the blending conditions of high-sulfur coal and non-coking coal according to claim 1, characterized in that, In step S3, the specific implementation method for washing the desulfurized coal gas to recover crude benzene is as follows: The benzene hydrocarbons in the coal gas are absorbed countercurrently by the wash oil in the benzene washing tower. The coal gas temperature at the inlet of the benzene washing tower is controlled at 25.0℃-27.0℃, and the wash oil temperature is controlled to be 2.0℃-4.0℃ higher than the coal gas temperature. The liquid-to-gas ratio of the wash oil circulation volume should be controlled at 1.6-2.0 L / m³. 3 ; The wash oil is a high-temperature coal tar fraction with a distillation range of 230℃-300℃.

8. The crude benzene production enhancement coal blending process under the blending conditions of high-sulfur coal and non-coking coal according to claim 1, characterized in that, In step S1, the specific control parameters for the crushing and mixing are as follows: the mass ratio of particles with a diameter of less than 3.0 mm in the blended coal after crushing is controlled to be 78.0%-82.0%, and the moisture content of the blended coal is adjusted to 8.5%-9.5%.

9. The crude benzene production enhancement coal blending process under the blending conditions of high-sulfur coal and non-coking coal according to claim 1, characterized in that, The process also includes a feedback adjustment step: The yield of crude benzene in step S3 and the post-reaction strength of the coke obtained in step S2 were determined. When the crude benzene yield is less than 1.2%, the proportion of long-flame coal in the first component should be increased while maintaining the overall atomic carbon-hydrogen ratio at 1.0-1.

5. When the strength of coke after reaction is less than 60%, the mass ratio of the second component in the blended coal should be increased.

10. A crude benzene production-increasing coal blending system under the condition of blending high-sulfur coal and non-coking coal, characterized in that, The system is applied to the crude benzene production enhancement coal blending process under the blending conditions of high-sulfur coal and non-coking coal as described in any one of claims 1-9, and the system comprises: The coal quality characteristic detection unit is used to obtain data on the physicochemical properties and hydrocarbon content of a single type of coal. The data processing and coal blending control unit is connected to the coal quality characteristic detection unit and is used to calculate the blending ratio of each component based on the physicochemical properties of the raw coal, the carbon and hydrogen content data, and the preset constraint that the comprehensive atomic carbon-hydrogen ratio is 1.0-1.

5. A precise batching and preparation unit is connected to the data processing and coal blending control unit and is used to prepare blended coal according to the blending ratio. The top-loading coke oven reaction unit is used to perform directional pyrolysis on the blended coal and control the temperature at the end of coking to obtain coke and raw coal gas. The raw coal gas condensation and separation unit is connected to the raw coal gas outlet of the top-charged coke oven reaction unit. It is used to cool the raw coal gas produced by the top-charged coke oven reaction unit and separate tar and ammonia water to obtain pre-cooled coal gas. A pre-desulfurization unit is installed in the flow path after the raw coal gas is condensed and separated. It is used to desulfurize the initially cooled coal gas to remove hydrogen sulfide before crude benzene recovery, thereby obtaining desulfurized coal gas. A crude benzene washing and recovery unit is located downstream of the pre-desulfurization unit and is used to recover crude benzene from the desulfurized coal gas. The product feedback monitoring unit is connected to the top-loading coke oven reaction unit and the crude benzene washing and recovery unit, respectively, and is used to detect the post-reaction strength of the coke and the yield of the crude benzene, and transmit the post-reaction strength and the yield as feedback data to the data processing and coal blending control unit.

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