Method for preparing autoclaved sand-lime bricks from dry residue after oil-based rock cuttings processing

Abstract

The present invention discloses a method for preparing autoclaved lime-sand bricks from dry residue after processing oil-based rock cuttings, and relates to the technical field of building materials. The present invention uses ash residue produced after treating the oil-based rock cuttings with an anaerobic thermal desorption process as raw material, wherein the raw material ratio is 81.3% ash residue, 7.32% cement, and 11.38% water. The raw material is stirred by a wheel mixer to become a water-containing colloid, and then the colloid is screened, crushed, statically pressed, and statically cured. Finally, the colloid is processed in an autoclave at high temperature and high pressure to become a finished autoclaved lime-sand brick. The present invention uses ash residue produced after treating the oil-based rock cuttings with an anaerobic thermal desorption process, and then uses the processed ash residue to produce autoclaved lime-sand bricks. This method can greatly improve the utilization rate of the oil-based rock cuttings.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, and in particular to a method for preparing autoclaved lime sand bricks from dry residues after oil-based rock cuttings are processed. Background Art

[0002] Oil-based rock cuttings are a type of oil-containing solid waste produced when oil-based drilling fluid is used to open up oil and gas "channels". During the exploration and development of resources such as shale gas, due to the complex mineral composition of shale, in order to ensure the stability of the well wall and reduce well control risks, oil-based mud with a certain proportion of proppant must be used as drilling fluid. In this way, the amount of oil-based rock cuttings produced increases accordingly. Its main components include oil, water, drill cuttings, high molecular compounds and other impurities, including a variety of harmful substances that are difficult to degrade in the natural environment.

[0003] Existing methods for processing oil-based rock cuttings include pyrolysis, solvent extraction technology, incineration technology, physicochemical separation technology, solidification technology, thermal desorption treatment technology and biodegradation. Oil-based rock cuttings after pyrolysis, physicochemical separation and thermal desorption treatment technology can be recycled. These treatment methods have laid the foundation for the environmentally friendly utilization of oil-based rock cuttings.

[0004] Autoclaved sand-lime brick is a common sand-lime brick made of sand and lime as the main raw materials, which is prepared by blank preparation, pressed into shape, and cured by high-pressure steam. Autoclaved sand-lime brick is a new building material with mature technology, excellent performance and energy saving. It is suitable for load-bearing walls of multi-story mixed structure buildings. Summary of the Invention

[0005] In response to the above technical problems, the present invention proposes the following technical solutions for utilizing oil-based rock cuttings in building materials:

[0006] A method for preparing autoclaved sand-lime bricks from dry residue after processing oil-based rock cuttings, characterized by comprising the following steps:

[0007] Step 1: The oil-based rock cuttings are treated with an anaerobic thermal desorption process to produce ash, which is cooled by a refrigeration auger. The cooled ash is then crushed by a two-stage crusher. The crushed ash is screened by a vibrating screen with a mesh size of 0.8 cm. The screened ash is one of the raw materials.

[0008] Step 2: Prepare auxiliary cement, the cement grade is PO42.5R.

[0009] Step 3: Weigh the ash, cement and water using the meter in the meter;

[0010] Step 4: Put the ash and cement into the wheel mixer, let the wheel mixer stir the ingredients, and at the same time transport them to the water adder equipped with the wheel mixer through a water pump, and evenly spray them in the wheel mixer for stirring. The ingredient ratio is 81.3% ash, 7.32% cement, and 11.38% water. The finished product after stirring is a water-containing colloid.

[0011] Step 5: The water-containing colloidal intermediate material after stirring is sent to a drum screening machine through a closed conveyor. When the drum screening machine screens the water-containing colloidal material, the colloidal material or hard stones larger than 5 mm in the material are screened out.

[0012] Step 6: The screened aqueous colloidal material is conveyed to a grinder by a closed belt for crushing. The grinder has the functions of breaking up and crushing. The grinder controls the fineness of the aqueous colloidal material to within 4 mm. The crushed material is conveyed to the next process by a closed belt.

[0013] Step 7: The crushed material is pressed into shape by a bidirectional simulated static press, and then the autoclaved brick body is taken out from the bidirectional simulated static press.

[0014] Step 8: Before entering the autoclave, the bricks pressed out of the brick machine are placed in a natural environment for one to two hours to reduce excess moisture in the autoclaved bricks.

[0015] Step 8: Use a double-opening autoclave, place the autoclaved brick body into the autoclave, seal it, and then introduce steam. After the steam is introduced into the autoclave, the space inside the autoclave is pressurized to 10 MPa, and the temperature inside the autoclave is maintained at 250 to 300 degrees. Under this state, autoclave and pressure are maintained for three hours, and then the autoclave is opened. After the autoclave is autoclaved at high temperature and high pressure in the autoclave and reaches a certain strength, it becomes a finished autoclaved lime sand brick.

[0016] Step 9: Take out the finished autoclave lime sand bricks from the autoclave and place them in the finished product yard in a natural environment.

[0017] Compared with the prior art, the present invention has the following advantages: (1) the present invention produces ash residue by treating oil-based rock cuttings with an anaerobic thermal desorption process, and then uses the treated ash residue to make autoclaved fly ash bricks, which can greatly improve the utilization rate of oil-based rock cuttings; (2) the present invention uses a specific proportion of oil-based rock cuttings to make autoclaved fly ash bricks, which can not only make the autoclaved fly ash bricks reach the strength of superior products, but also further reduce the production cost of autoclaved fly ash bricks. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0019] A method for preparing autoclaved sand-lime bricks from dry residue after processing oil-based rock cuttings comprises the following steps:

[0020] Step 1, oil-based rock cuttings processing: The oil-based rock cuttings produce ash after anaerobic thermal desorption treatment, and then the ash is specially treated so that the dry slag is suitable for brick making raw materials. The specific process is that the ash after anaerobic thermal desorption treatment is first cooled by a refrigeration auger, and the refrigeration auger cools the ash from about 320℃ to about 50℃, and then the ash enters a double-stage hammer crusher, and is crushed by the double-stage hammer crusher. The crushed ash is transported to an ash tank through a screw conveyor and an elevator. In the process of loading the dry slag from the ash tank into the ash tank transport vehicle, it is screened by a vibrating screen. The screen size of the vibrating screen is 0.8 cm. Its purpose is to screen out materials exceeding 0.8 cm in the ash, such as iron blocks, debris, etc., and the ash that is less than 0.8 cm after the vibrating screen is loaded into an ash tank truck and transported to the brick factory, and then put into the ash tank in the brick factory as the main raw material for autoclaved lime sand bricks.

[0021] Step 2: Raw material preparation: prepare cement, ash, and water. The cement grade is PO42.5R. The raw materials, cement and ash, are transported to the production workshop by special tank trucks. After connecting the tank trucks to the cement silo and ash silo through pipelines, they are transported to the cement silo and ash silo by air pumps for standby use.

[0022] Step 3: Batching and mixing: According to the ratio of cement 11.38% and ash 81.3%, the raw materials are measured in the meter and then enter the batching machine. Then the batching machine puts the ash and cement into the wheel mixer, and the wheel mixer stirs the ingredients. At the same time, water is pumped into the water adder equipped with the wheel mixer through the water pump. The water adder will spray the water evenly in the wheel mixer for stirring. The batching ratio is 81.3% of ash, 7.32% of cement, and 11.38% of water. The finished product after stirring is a water-containing colloid. For example, the weight of the raw materials entering the batching machine at one time are: 1500 kg of ash and 135 kg of cement. Then, 210 kg of water is evenly fed into the mixer through the water adder. The uniform stirring in the mixer is completed after 360 seconds.

[0023] Step 4: Screening: The water-containing colloidal intermediate material after stirring is sent to a drum screening machine through a closed conveyor. When the drum screening machine screens the water-containing colloidal material, the colloidal material or hard stones larger than 5 mm in the material are screened out.

[0024] Step 5: Crushing: The screened water-containing colloidal material is conveyed to the crusher by a closed belt for crushing. The crusher has the functions of breaking up and crushing. The crusher can control the fineness of the material within 4mm. The crushed material is conveyed to the brick machine receiving hopper by a closed belt.

[0025] Step 6: Compression molding: The crushed material is pressed into autoclaved brick bodies through a two-way simulated static press. The autoclaved brick bodies are stacked on a steaming trolley by an automatic stacker and enter the static curing area.

[0026] Step 7. Resting: The purpose of resting is to allow some of the excess water in the autoclaved bricks to evaporate, so as to prevent the subsequent autoclaved bricks from cracking due to the expansion of water due to heat during the heating process. Secondly, resting can increase the strength of the autoclaved bricks, thereby improving the strength of the product. Generally, the resting time for autoclaved bricks is 1-2 hours.

[0027] Step 8. Autoclave curing: The autoclave is a double-opening type. The grouped autoclaved bricks enter the autoclave along the track and are sealed. Then steam is introduced into the autoclave. The autoclaved bricks are autoclaved at high temperature and high pressure in the autoclave before the furnace is opened to produce bricks. During this process, the steam in the autoclave must be kept at a pressure of 10 MPa and a temperature of 250-300 degrees Celsius. The autoclave is maintained for 3 hours, and then the pressure is maintained for another 3 hours. After the autoclaved bricks reach a certain strength, they become finished autoclaved fly ash bricks. The steam used in the specific autoclave process is provided by the natural gas boiler installed in the factory.

[0028] Step 9: Finished product stacking: The lime sand bricks after leaving the furnace are transported to the finished product yard by crane for inspection and sale.

[0029] The autoclaved sand-lime bricks produced using oil-based rock cuttings according to this method have an average compressive strength of 26.9MPa, which fully meets the strength index of superior autoclaved sand-lime bricks (>25MPa). At the same time, the other indicators of autoclaved sand-lime bricks, such as radionuclide limit, frost resistance, water absorption rate, linear drying shrinkage rate and softening coefficient, also fully meet the national standard "Autoclaved Sand-lime Brick" (GB11945-1999).

Claims

1. A method for preparing autoclaved lime sand bricks from dry residue after oil-based rock cuttings treatment, characterized in that The following steps are involved: Step 1: treating the oil-based rock cuttings with an anaerobic thermal desorption process to produce ash residue; Step 2: Prepare auxiliary cement, the cement grade is PO42.5R; Step 3: Weigh the ash, cement and water using the meter in the meter; Step 4: Put the ash and cement into a wheel mixer, let the wheel mixer stir the ingredients, and at the same time, transport them to the water adder equipped with the wheel mixer through a water pump, and evenly spray them in the wheel mixer for stirring. The ingredient ratio is 81.3% ash, 7.32% cement, and 11.38% water. The finished product after stirring is a water-containing colloid. Step 5: The water-containing colloidal intermediate material after stirring is sent to a drum screening machine through a closed conveyor for further screening; Step 6: The screened water-containing colloidal material is conveyed to the crusher by a closed belt for crushing, and the crushed material is conveyed to the next process by a closed belt; Step 7: The crushed material is pressed into shape by a bidirectional simulated static press, and then the autoclaved brick body is taken out from the bidirectional simulated static press; Step 8: Place the autoclaved brick body in a natural environment for one to two hours to reduce excess moisture in the autoclaved brick body; Step 9: Use a double-opening autoclave to place the autoclaved brick body into the autoclave, seal it, and then introduce steam. After the autoclaved brick body reaches a certain strength after being autoclaved at high temperature and high pressure in the autoclave, it becomes an autoclaved sand-lime brick product. The pressure in the autoclave is kept at 10 MPa and the temperature in the autoclave is kept at 250 to 300 degrees Celsius. In this state, autoclave and pressure holding are carried out for three hours. Step 10: Take out the finished autoclaved sand-lime bricks from the autoclave and place them in a finished product yard in a natural environment; Step 11: Check the compressive strength of the finished autoclaved sand-lime brick. If it is >25MPa, it meets the inspection standards.

2. The method for preparing autoclaved sand-lime bricks from dry residue after processing oil-based rock cuttings according to claim 1, characterized in that: In step 1, the ash produced after the oil-based rock cuttings are treated by an anaerobic thermal desorption process is pretreated. The ash is cooled by a refrigeration auger, and then the cooled ash is crushed by a two-stage crusher. The crushed ash is screened by a vibrating screen with a mesh size of 0.8 cm. The screened ash is one of the raw materials.

3. The method for preparing autoclaved sand-lime bricks from dry residue after processing oil-based rock cuttings according to claim 1, characterized in that: When the drum screening machine in step 5 screens the aqueous colloid, the colloid or hard stones larger than 5 mm in the material are screened out.

4. The method for preparing autoclaved sand-lime bricks from dry residue after processing oil-based rock cuttings according to claim 1, characterized in that: The pulverizer in step six has the functions of breaking up and crushing, and the pulverizer controls the fineness of the aqueous colloidal material to within 4 mm.

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