System and method for cooperatively treating oil-based rock debris, waste drilling mud and power plant wastewater through coal-fired boiler

Abstract

The invention belongs to the related technical field of oil-containing pollutant and wastewater treatment, and particularly relates to a system and method for cooperatively treating oil-based rock debris, waste drilling mud and power plant wastewater through a coal-fired boiler. Comprising an oil-based rock debris storage pool, a first stirring device, a filtering device, a waste drilling mud storage pool, a second stirring device, a finished slurry storage pool, a third stirring device and a coal-fired boiler. Through double-line treatment, the purpose that the coal-fired boiler co-treats the oil-based rock debris, the waste drilling mud and the power plant wastewater for resource utilization is achieved, and the technical problems that in the prior art, an oil-based rock debris treatment technology is complex in process, high in treatment cost and low in treatment efficiency are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field related to oil-containing pollutants and wastewater treatment, and specifically relates to a system and method for collaboratively treating oil-based rock cuttings, waste drilling mud and power plant wastewater using coal-fired boiler power generation. Background Art

[0002] Oil-based drilling fluid is a commonly used drilling fluid in the oil / gas drilling process, which plays the role of supporting the well wall and transporting rock fragments. During the oil / gas drilling process, the oil-based drilling fluid continuously sends rock fragments to the surface through the drilling fluid circulation system, and the solid waste generated is the oil-based rock fragments. At the same time, a large amount of waste drilling mud is also generated due to the following reasons: 1. Drilling fluid that is replaced due to changes in drilling engineering and geological requirements; 2. Drilling fluid that is discarded due to unqualified performance; 3. Drilling fluid leaked from the drilling fluid circulation system. Each oil / gas drilling well is expected to generate approximately 300m 3 of waste drilling mud and 500m 3 Oil-based rock cuttings. In recent years, with the vigorous development of my country's oil and gas exploration and production industry, millions of tons of oily waste are generated every year.

[0003] Oil-based drilling fluid is a colloidal suspension system based on mineral oil or diesel fuel, supplemented with water, weighting agents, and various chemical additives. Petroleum-based substances, various chemical additives, and organic compounds are the primary contributors to environmental pollution. Oil-based cuttings and waste drilling mud are primarily composed of oil-based drilling fluid and rock fragments, but the proportions of these components vary. Oil-based cuttings are composed of 2-10% water, 10-20% oil, and 60-70% inorganic mineral phases. Waste drilling mud is composed of 20-30% water, 40-50% oil, and 20-30% inorganic mineral phases. Furthermore, the inorganic mineral phase particles in oil-based cuttings are larger in size, while the inorganic mineral phase particles in oil-based mud are finer.

[0004] Currently, the main treatment methods for oil-based cuttings and waste drilling mud include centrifugation, solidification, solvent extraction, reinjection, pyrolysis, incineration, and composting. Incineration is a simple and efficient method that not only directly removes most hazardous substances but also utilizes the heat generated during the incineration process. Using coal-fired boilers to co-process oil-based cuttings and waste drilling mud not only completely eliminates organic pollutants but also, when combined with the boiler system's desulfurization, denitrification, and dust removal equipment, allows for clean and harmless disposal of combustion flue gases.

[0005] In addition, the disposal of power plant wastewater is also one of the core issues in power plant environmental protection. Coal-fired power plants have complex water systems, and the types and levels of pollutants in wastewater vary depending on their uses. The main sources of their wastewater include: circulating water systems, industrial water systems, domestic and fire water systems, slag removal systems, and desulfurization systems. The wastewater composition is complex, mainly inorganic substances, and contains some organic pollutants (mainly oil substances). If coal-fired boilers can be used to incinerate power plant wastewater, the complexity and cost of power plant wastewater treatment can be greatly reduced. In the prior art, there are no systems and methods for using coal-fired boilers to co-dispose of oil-based rock cuttings, waste drilling mud, and power plant wastewater. Prior art CN 118031241 A discloses a system and method for safely co-firing oil-based rock cuttings in coal-fired boilers. This technology uses pyrolysis + incineration technology to fully utilize the heat of oil-based rock cuttings and reduce the generation of harmful substances. However, this technology has high energy consumption and involves high investment costs due to the modification of secondary air ducts and the construction of pyrolysis systems. Long-term operation of pyrolysis equipment can lead to coking and carbon deposition, impacting efficiency. Furthermore, pyrolysis processing of oil-based rock chips is slow, and the oil recovery process limits the processing speed of oil-based rock chips. Therefore, a relatively simple, fast, low-cost, and energy-efficient system and method for co-firing oil-based rock chips in coal-fired boilers is urgently needed. Summary of the Invention

[0006] To address the above-mentioned deficiencies or improvement needs of the prior art, the present invention provides a system and method for the coordinated treatment of oil-based cuttings, waste drilling mud, and power plant wastewater using a coal-fired boiler, thereby resolving the technical issues of high cost and low efficiency in the prior art of treating oil-based cuttings.

[0007] To achieve the above objectives, a system is provided for the coordinated treatment of oil-based rock cuttings, waste drilling mud, and power plant wastewater using a coal-fired boiler. The oil-based rock cuttings are primarily composed of 2-10% water, 10-20% oil, and 60-70% large-particle inorganic mineral phases, with the particle size of the large-particle inorganic mineral phase ranging from 1 μm to 5 mm. The waste drilling mud is primarily composed of 20-30% water, 40-50% oil, and 20-30% small-particle inorganic mineral phases, with the particle size of the small-particle inorganic mineral phase ranging from 1 to 100 μm. The power plant wastewater, derived from the circulating water system, boiler blowdown system, or desulfurization and denitrification system of a thermal power plant, primarily contains salts, Cl ions, and trace amounts of heavy metals.

[0008] According to one aspect of the present invention, a system for collaboratively processing oil-based rock cuttings, waste drilling mud, and power plant wastewater using a coal-fired boiler is provided, comprising an oil-based rock cuttings storage tank, a first stirring device, a filtering device, a waste drilling mud storage tank, a second stirring device, a finished slurry storage tank, a third stirring device, and a coal-fired boiler; the oil-based rock cuttings storage tank, the first stirring device, the filtering device, the second stirring device, the finished slurry storage tank, and the coal-fired boiler are sequentially connected from left to right via pipelines; the first stirring device is connected to the power plant wastewater pipeline; the second stirring device is connected to the waste drilling mud storage tank via a pipeline; the filtering device is connected to the third stirring device via a pipeline, and the third stirring device is connected to the coal-fired boiler via a pipeline; the third stirring device is also connected to a raw coal conveying device.

[0009] Preferably, a crushing device and a first delivery pump are further provided on the pipeline connecting the oil-based rock cuttings storage tank and the first stirring device; and a second delivery pump is provided on the power plant wastewater pipeline.

[0010] Preferably, a third delivery pump is provided on the pipeline connecting the filtering device and the second stirring device; and a fourth delivery pump is provided on the pipeline connecting the second stirring device and the waste drilling mud storage tank.

[0011] Preferably, a fifth delivery pump is provided on the pipeline connecting the finished slurry storage tank and the coal-fired boiler; and an oil gun is provided on the pipeline connecting the fifth delivery pump and the coal-fired boiler.

[0012] Preferably, a coal conveying belt and a coal grinding system are sequentially arranged on the pipeline connecting the third stirring device and the coal-fired boiler.

[0013] According to another aspect of the present invention, a method for collaboratively treating oil-based cuttings, waste drilling mud, and power plant wastewater using a coal-fired boiler is provided, comprising the following steps:

[0014] S1 crushes the oil-based rock cuttings and fully mixes them with power plant wastewater to obtain a mixture of oil-based rock cuttings and power plant wastewater;

[0015] S2 filtering the mixture of the oil-based rock cuttings and the power plant wastewater to obtain a filtrate and a filter residue;

[0016] S3: mixing the filtrate with waste drilling mud to form a finished slurry, and heating the finished slurry;

[0017] S4: mixing the filter residue with raw coal and grinding them to obtain mixed coal powder;

[0018] In S5, the heated finished slurry and the mixed pulverized coal are introduced into a coal-fired boiler, so that the finished slurry and the mixed pulverized coal are coupled and burned.

[0019] Preferably, the oil-based rock cuttings and power plant wastewater are mixed in a mass ratio of 1:(1-2).

[0020] Preferably, the mass mixing ratio of the oil-based rock cuttings and power plant wastewater mixture to the waste drilling mud is 1:(1-2), and the stirring time is 20-60 minutes.

[0021] Preferably, the heating temperature in step S3 is 80-90°C.

[0022] Preferably, the temperature of the power plant wastewater is 40-50° C., and the stirring time is 20-60 minutes.

[0023] Preferably, the sieve plate used in the filtering device has a pore size of 5 to 10 mm.

[0024] Preferably, the filter residue and the raw coal are mixed in a mass ratio of 1:(20-50).

[0025] Preferably, the volume-to-weight ratio of the finished slurry to the mixed coal powder is 0.03-0.07 L / kg.

[0026] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0027] 1. The present invention mixes oil-based rock cuttings with power plant wastewater, diluting the oil-based rock cuttings with the wastewater to increase their fluidity and facilitate subsequent filtration and atomized combustion. The filter residue screened by the filter device, after dilution and washing with the wastewater, has a significantly reduced oil content, preventing the release of excess oil and gas during subsequent pulverization with raw coal, significantly reducing the risk of explosions and deflagrations in the pulverizing system. The filter device removes incompletely crushed, large, inorganic rock fragments from the oil-based rock cuttings, improving the atomization effect of subsequent atomized combustion. The filter residue produced during the production process is mixed with raw coal in the boiler's pulverizing system and pulverized, then fed into the boiler for combustion. This dual-line treatment achieves the harmless and resourceful disposal of oil-based rock cuttings, waste drilling mud, and power plant wastewater.

[0028] 2. The present invention heats the finished slurry storage tank to increase the finished slurry's temperature, reduce viscosity, and increase fluidity, enhancing the atomized combustion effect. The higher initial temperature also facilitates combustion in the furnace. The finished slurry is atomized with an oil gun and fed into a boiler for coupled combustion with pulverized coal. Exhaust gas drilling mud and oil-based cuttings share a common source and similar composition. Mixing the exhaust gas drilling mud with the filtrate facilitates simultaneous processing of both oil-based cuttings and exhaust gas drilling mud.

[0029] 3. The present invention utilizes power plant wastewater to produce finished slurry and achieves coordinated disposal through atomized spray combustion. Compared with the existing technology that utilizes pyrolysis and incineration to treat oil-based cuttings, the present invention avoids the complex oil recovery process and uses simple methods such as dilution filtration to separate most of the oil phase. At the same time, the fluidity of the oil-based cuttings is further improved by adding power plant wastewater to meet the process requirements of atomized spray combustion to treat oil-based cuttings. Atomized spray combustion can continuously feed and process oil-based cuttings and waste drilling mud on a large scale. The processing capacity is far higher than other technologies, and the atomized oil droplets can fully contact the air in the high temperature environment of the boiler, and the combustion efficiency is relatively high. The present invention not only greatly simplifies the process flow of oil-based cuttings treatment and coordinates the disposal of power plant wastewater, but also can continuously process oil-based cuttings and waste drilling mud in large quantities.

[0030] 4. In the first stirring device of the present invention, the oil-based rock cuttings and power plant wastewater are mixed in a mass ratio of 1:(1-2). In the second stirring device, the oil-based rock cuttings and power plant wastewater mixture is mixed with the waste drilling mud in a mass ratio of 1:(1-2). The finished slurry produced by this mixing ratio maintains fluidity while having an appropriate calorific value, meeting the requirements of atomization and furnace combustion.

[0031] The filter residue is mixed with the raw coal at a mass ratio of 1: (20-50). Since the filter residue has a low calorific value and a high ash content, a high mixing ratio will have a significant impact on boiler combustion. Coal powder produced according to the above mixing ratio can reduce the impact on the calorific value of the coal powder.

[0032] The volume-to-weight ratio of the finished product slurry to the mixed coal powder is 0.03-0.07 L / kg. According to the above-mentioned finished product slurry blending ratio, the impact of the finished product slurry blending on boiler combustion can be reduced, thereby ensuring boiler combustion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention is a schematic diagram of a system for the coordinated disposal of oil-based rock cuttings, waste drilling mud and power plant wastewater by coal-fired boilers.

[0034] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0035] 1. Oil-based rock cuttings storage tank; 2. Crushing device; 3. First delivery pump; 4. Second delivery pump; 5. First stirring device; 6. Filter device; 7. Third delivery pump; 8. Waste drilling mud storage tank; 9. Fourth delivery pump; 10. Second stirring device; 11. Finished slurry storage tank; 12. Fifth delivery pump; 13. Oil gun; 14. Third stirring device; 15. Coal conveyor belt; 16. Coal grinding system; 17. Coal-fired boiler; 18. Power plant wastewater pipeline; 19. Raw coal conveying device. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0037] Example 1

[0038] The present invention provides a system for the coordinated disposal of oil-based rock cuttings, waste drilling mud and power plant wastewater by a coal-fired boiler. The system realizes the coordinated disposal of oil-based rock cuttings, waste drilling mud and power plant wastewater, fully utilizes the heat generated by incineration, reduces power generation costs, and realizes the clean and harmless treatment of oil-based rock cuttings, waste drilling mud and power plant wastewater.

[0039] The system includes an oil-based rock cuttings storage tank 1, a crushing device 2, a first delivery pump 3, a second delivery pump 4, a first stirring device 5, a filtering device 6, a third delivery pump 7, a waste drilling mud storage tank 8, a fourth delivery pump 9, a second stirring device 10, a finished slurry storage tank 11, a fifth delivery pump 12, an oil gun 13, a third stirring device 14, a coal conveyor belt 15, a coal grinding system 16, a coal-fired boiler 17, a plant wastewater pipeline 18 and a raw coal conveyor belt 19.

[0040] The oil-based rock cuttings storage tank 1, the first stirring device 5, the filtering device 6, the second stirring device 10, the finished slurry storage tank 11, and the coal-fired boiler 17 are connected in sequence from left to right through pipelines; the first stirring device 5 is connected to the power plant wastewater pipeline 18; the second stirring device 10 is connected to the abandoned drilling mud storage tank 8 through a pipeline; the filtering device 6 is connected to the third stirring device 14 through a pipeline, and the third stirring device 14 is connected to the coal-fired boiler 17 through a pipeline; the third stirring device 14 is also connected to the raw coal conveyor belt 19.

[0041] The oil-based rock cuttings in the oil-based rock cuttings storage tank 1 are crushed by the crushing device 2 and then transported to the first stirring device 5 by the first delivery pump 3. The power plant wastewater is transported to the first stirring device 5 by the second delivery pump 4. The first and second delivery pumps 3 and 4 have variable frequency control functions, adjusting the delivery rate of the oil-based rock cuttings and power plant wastewater according to a mass ratio of 1:2. The filtering device 6 uses a sieve plate to filter out larger particles from the oil-based rock cuttings and power plant wastewater mixture and transports them to the third stirring device 14. The remaining mixture flows out through the sieve plate holes.

[0042] The waste drilling mud storage tank 8 is used to store waste drilling mud, which is delivered to the second stirring device 10 by a fourth delivery pump 9. The filtrate at the outlet of the filter device 6 is delivered to the second stirring device 10 by a third delivery pump 7. The fourth and third delivery pumps 9 and 7 have variable frequency control functions, adjusting the delivery rate of the oil-based cuttings / power plant wastewater mixture and the waste drilling mud to maintain a 1:1 mass ratio.

[0043] The finished product slurry storage tank 11 is used to store the finished product slurry from the second stirring device 10. The finished product slurry is heated to 80°C in the finished product slurry storage tank 11 by a heating device and then transported to the oil gun 13 via an insulated pipe by a fifth delivery pump 12. The fifth delivery pump 12 has a variable frequency control function, adjusting the delivery rate based on the slurry mixing ratio. The finished product slurry is dispersed and atomized into an aerosol by compressed air, which is then sprayed into the coal-fired boiler 17 for combustion via the oil gun 13. The compressed air pressure can be adjusted.

[0044] The filter residue screened out by the filter device 6 and the raw coal enter the third stirring device 14 at a mass ratio of 1:20 and are directly sent to the coal grinding system 16 for pulverization through the coal conveyor belt 15.

[0045] After the filter residue screened by the filter device 6 is washed and diluted with power plant wastewater, its oil content is greatly reduced, so that no excessive oil and gas will be released during the subsequent processing of the pulverizing system, greatly reducing the probability of deflagration and explosion accidents in the pulverizing system, and ensuring the safe operation of the coal-fired boiler 17.

[0046] The present invention also provides a method for the coordinated treatment of oil-based rock cuttings, waste drilling mud and power plant wastewater by coal-fired boilers. The method adopts the above-mentioned system for the coordinated treatment of oil-based rock cuttings, waste drilling mud and power plant wastewater by coal-fired boilers to burn oil-based rock cuttings, waste drilling mud and power plant wastewater in coal-fired boilers.

[0047] Specifically, oil-based rock cuttings storage tank 1 is used to temporarily store oil-based rock cuttings. It is a fully enclosed storage tank equipped with a negative pressure system to prevent volatile substances in the oil-based rock cuttings from entering the atmosphere, effectively preventing air pollution. A screw pump is installed at the bottom of oil-based rock cuttings storage tank 1, which transports the oil-based rock cuttings to crushing device 2, which uses a hammer crusher for crushing.

[0048] Power plant wastewater and crushed oil-based rock chips are delivered to a first agitator 5 by a first pump 3 and a second pump 4, each with adjustable delivery rates, at a mass mixing ratio of 1:2. Mixing and stirring are continued for 30 minutes. The power plant wastewater temperature is 40°C. The fan speed in the first agitator 5 is adjustable at approximately 200 rpm. A filter 6, using a linear sieve-type screening machine with a 5mm sieve plate, separates the oil-based rock chips produced by the first agitator 5 from the large debris in the power plant wastewater mixture. Raw coal and filter residue are then mixed and stirred in a third agitator 14 at a mass mixing ratio of 1:20. The mixture is then conveyed by a coal conveyor 15 to a coal grinding system 16, where it is ground, dried, and powdered for combustion in a coal-fired boiler 17. The third agitator 14 and coal conveyor 15 have a maximum processing capacity of 50 tons per hour. The oil content of the filter residue is ≤2%, and no excessive oil and gas will be released during the subsequent processing of the pulverizing system, which greatly reduces the probability of deflagration and explosion accidents in the pulverizing system.

[0049] The waste drilling mud storage tank 8 is a fully enclosed negative pressure storage tank. The filtrate filtered out of the filter device 6 and the drilling mud stored in the waste drilling mud storage tank 8 are respectively delivered to the second stirring device 10 by the third delivery pump 7 and the fourth delivery pump 9 in a mass mixing ratio of 1:1 for mixing. The stirring time is about 30 minutes. The fan speed of the second stirring device 10 is about 100 rpm, and the fan speed and rotation direction are adjustable. After stirring is completed, it is sent to the finished slurry storage tank 11, which is a fully enclosed negative pressure storage tank equipped with a heating device. After the finished slurry is heated to 80°C, it is sent to the oil gun for atomization and combustion by the fifth delivery pump 12 through the insulated pipe.

[0050] The finished slurry is dispersed into a fine mist by compressed air in the oil gun 13 before entering the coal-fired boiler 17 for combustion. The compressed air pressure can be adjusted to ensure stable atomization performance. The oil gun 13 can adjust the delivery rate based on the blending ratio of the finished slurry. The volume-to-weight ratio of the finished slurry to the mixed pulverized coal is 0.03 L / kg.

[0051] Example 2

[0052] The present invention provides a method for the coordinated disposal of oil-based rock cuttings, waste drilling mud and power plant wastewater by using a coal-fired boiler. The system realizes the coordinated disposal of oil-based rock cuttings, waste drilling mud and power plant wastewater, and fully utilizes the heat generated by their incineration, thereby reducing the cost of power generation and achieving the clean and harmless treatment of oil-based rock cuttings, waste drilling mud and power plant wastewater.

[0053] A method for collaboratively treating oil-based rock cuttings, waste drilling mud, and power plant wastewater using a coal-fired boiler comprises the following steps:

[0054] S1 delivers the oil-based rock cuttings into the crushing device 2, delivers the oil-based rock cuttings processed by the crushing device 2 to the first stirring device 5 via the first delivery pump 3, and simultaneously delivers the power plant wastewater to the first stirring device 5 via the second delivery pump 4, so that the oil-based rock cuttings and the power plant wastewater are fully mixed and stirred to obtain a mixture of the oil-based rock cuttings and the power plant wastewater;

[0055] S2: The mixture of oil-based rock cuttings and power plant wastewater is passed into the filter device 6 for filtration, and the filtrate is delivered to the second stirring device 10 by the third delivery pump 7; the filtered residue is passed into the third stirring device 14;

[0056] S3: The waste drilling mud is delivered by the fourth delivery pump 9 to the second stirring device 10, where it is stirred and mixed with the filtrate to form a finished slurry, and the finished slurry is delivered to the finished slurry storage tank 11 for storage and heating;

[0057] In step S4, the raw coal is passed through the raw coal conveyor belt 19 into the third stirring device 14, the filter residue obtained in step S2 is mixed and stirred with the raw coal in the third stirring device 14, and then sent to the boiler coal grinding system 16 through the coal conveyor belt 15 to be ground into mixed coal powder, and then the mixed coal powder is sent to the coal-fired boiler 17;

[0058] In step S5 , the heated finished slurry is delivered to the oil gun 13 by the fifth delivery pump 12 , atomized by the oil gun 13 , and sprayed into the coal-fired boiler 17 to be coupled with the mixed pulverized coal for combustion.

[0059] Oil-based rock cuttings storage tank 1 is a fully enclosed tank used for temporary storage of oil-based rock cuttings. It features a negative pressure system to prevent volatile components from the cuttings from entering the atmosphere, effectively preventing air pollution. A screw pump is installed at the bottom of the tank, pumping the cuttings to a crushing unit 2 for crushing. Crushing unit 2 utilizes a pin-type sand mill to grind the large rock fragments to less than 5 mm. Power plant wastewater is pumped by a second pump 4 with an adjustable delivery rate to a first agitator 5 at a mixing ratio of 1:1 oil-based rock cuttings:power plant wastewater for approximately 45 minutes. The temperature of the power plant wastewater is 40°C. The fan speed of the first agitator 5 is adjustable at approximately 250 rpm. The waste drilling mud storage tank is a fully enclosed negative pressure tank used for temporary storage of waste drilling mud. The mixture of oil-based rock cuttings and power plant wastewater produced by the first stirring device 5 and the drilling mud in the waste drilling mud storage tank 8 are respectively delivered to the second stirring device 10 by the third delivery pump 7 and the fourth delivery pump 9 in a mass mixing ratio of 1:2 for mixing and stirring, and the stirring time is about 45 minutes. The fan speed in the second stirring device 10 is about 150 rpm, and the fan speed is adjustable. After the stirring is completed, it is sent to the finished slurry storage tank 11 for storage. The finished slurry storage tank 11 is a fully enclosed negative pressure storage tank with a heating device. The finished slurry is heated to 90°C and sent to the oil gun 13 for atomization and combustion through the insulation pipe by the fifth delivery pump 12.

[0060] The finished slurry is dispersed into a fine mist by compressed air in the oil gun 13 before entering the coal-fired boiler 17 for combustion. The compressed air pressure can be adjusted to ensure stable atomization performance. The oil gun 13 can adjust the delivery rate of the finished slurry based on the blending ratio of the finished slurry to the pulverized coal mixture. The volume-to-weight ratio of the finished slurry to the pulverized coal mixture is 0.07 L / kg.

[0061] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A system for coordinating the treatment of oil-based rock cuttings, waste drilling mud and power plant wastewater by coal-fired boilers, characterized in that: The invention comprises an oil-based rock cuttings storage tank (1), a first stirring device (5), a filtering device (6), a waste drilling mud storage tank (8), a second stirring device (10), a finished slurry storage tank (11), a third stirring device (14) and a coal-fired boiler (17); the oil-based rock cuttings storage tank (1), the first stirring device (5), the filtering device (6), the second stirring device (10), the finished slurry storage tank (11) and the coal-fired boiler (17) are sequentially connected from left to right through pipelines; the first stirring device (5) is connected to the power plant wastewater pipeline (18); the second stirring device (10) is connected to the waste drilling mud storage tank (8) through a pipeline; the filtering device (6) is connected to the third stirring device (14) through a pipeline, and the third stirring device (14) is connected to the coal-fired boiler (17) through a pipeline; the third stirring device (14) is also connected to a raw coal conveying device (19).

2. A system for coordinating the treatment of oil-based rock cuttings, waste drilling mud and power plant wastewater by a coal-fired boiler according to claim 1, characterized in that: A crushing device (2) and a first delivery pump (3) are also provided on the pipeline connecting the oil-based rock cuttings storage tank (1) and the first stirring device (5); and a second delivery pump (4) is provided on the power plant wastewater pipeline (18).

3. The system for coordinating the treatment of oil-based rock cuttings, waste drilling mud and power plant wastewater by coal-fired boilers according to claim 1, characterized in that: A third delivery pump (7) is provided on the pipeline connecting the filtering device (6) and the second stirring device (10); and a fourth delivery pump (9) is provided on the pipeline connecting the second stirring device (10) and the waste drilling mud storage tank (8).

4. A system for coordinating the treatment of oil-based rock cuttings, waste drilling mud and power plant wastewater by a coal-fired boiler as claimed in claim 3, characterized in that: A fifth delivery pump (12) is provided on the pipeline connecting the finished product slurry storage tank (11) and the coal-fired boiler (17); and an oil gun (13) is provided on the pipeline connecting the fifth delivery pump (12) and the coal-fired boiler (17).

5. The system for coordinating the treatment of oil-based rock cuttings, waste drilling mud and power plant wastewater by coal-fired boilers according to claim 1, characterized in that: A coal conveying belt (15) and a coal grinding system (16) are sequentially arranged on the pipeline connecting the third stirring device (14) and the coal-fired boiler (17); the raw coal conveying device (19) is a raw coal conveying belt.

6. A method for collaboratively treating oil-based rock cuttings, waste drilling mud and power plant wastewater using a coal-fired boiler, characterized in that: The steps include: S1 crushes the oil-based rock cuttings and fully mixes them with power plant wastewater to obtain a mixture of oil-based rock cuttings and power plant wastewater; S2 filtering the mixture of the oil-based rock cuttings and the power plant wastewater to obtain a filtrate and a filter residue; S3: mixing the filtrate with waste drilling mud to form a finished slurry, and heating the finished slurry; S4: mixing the filter residue with raw coal and grinding them to obtain mixed coal powder; In S5, the heated finished slurry and the mixed pulverized coal are introduced into a coal-fired boiler, so that the finished slurry and the mixed pulverized coal are coupled and burned.

7. The method for collaboratively treating oil-based rock cuttings, waste drilling mud and power plant wastewater using a coal-fired boiler according to claim 6, characterized in that: The oil-based rock cuttings and power plant wastewater are mixed in a mass ratio of 1:(1-2).

8. The method for collaboratively treating oil-based rock cuttings, waste drilling mud and power plant wastewater using a coal-fired boiler according to claim 6, wherein: The mixture of the oil-based rock cuttings and the power plant wastewater is mixed with the waste drilling mud in a mass ratio of 1:(1-2), and the stirring time is 20-60 minutes.

9. The method for collaboratively treating oil-based rock cuttings, waste drilling mud and power plant wastewater using a coal-fired boiler according to claim 6, wherein: The heating temperature in step S3 is 80-90°C.

10. The method for collaboratively treating oil-based rock cuttings, waste drilling mud and power plant wastewater using a coal-fired boiler according to claim 6, wherein: The filter residue and the raw coal are mixed in a mass ratio of 1:(20-50); the volume weight ratio of the finished slurry to the mixed coal powder is 0.03-0.07 L / kg.

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