Worldwide, the dewatering of river silt is a major obstacle to river dredging projects. The desilting system with shaker, desander, and desilter can remove sludge above 25 microns, but fine particles below 25 microns cannot be processed. This is where the centrifuge comes in. In the case of mechanical separation without adding polymers, centrifuges can separate fine particles of more than 5 microns. Through the dosing flocculation technology, the centrifuge and polymer can be used together to achieve zero emissions.
River desilting centrifuge
For the separation of small particles, two types of separation equipment are usually selected, one is a centrifuge, and the other is a filter press.
Compared with the filter press, the centrifuge has the following advantages:
The use of centrifuge chemicals is significantly reduced because of the centrifuge’s high separation factor, which efficiently separates fine particles
Maintenance is easier and requires less service
It can be widely used in the treatment of silt in different waterways
It separates cleaner water
Using centrifuges is easier to install and requires a smaller footprint
Centrifuges can be operated automatically and require less manpower
It can save water resources required for washing equipment
The plate and frame filter press is through the extrusion of the plate and frame, so that the water in the sludge is discharged through the filter cloth to achieve the purpose of dehydration. Advantages: low price, good at dewatering inorganic sludge, mud cake moisture content is low.
Disadvantages: easy to clog, the need to use high-pressure pumps, not suitable for the dehydration of oily sludge, difficult to achieve continuous automatic operation.
When selecting equipment, the following aspects should be considered:
① Requirements for solid content of mud cake. Compared with other types of dehydrators, the solid content of the mud cake can reach 35%, if the consideration is taken from the factors of reducing the footprint of the sludge pile, the plate and frame filter press should be the solution.
② Material of the frame.
③ Filter plate and filter cloth material. Corrosion resistance is required, and the filter cloth should have a certain tensile strength.
④ Filter plate movement mode. The requirements can be fully automatic or semi-automatic through a hydraulic-pneumatic device to reduce the labor intensity of the operator.
⑤ Filter cloth oscillation device to make the filter cake easy to fall off. Compared with other types of dehydrators, the disadvantage of plate and frame filter press is that it occupies a larger area. At the same time, because the plate and frame filter press is intermittently operating, low efficiency, poor operating room environment, and secondary pollution, large domestic sewage disposal plants are rarely used.
Two, decanter sedimentation centrifuge:
The decanter type sedimentation centrifuge is mainly composed of a spiral conveyor with a hollow rotating shaft. After the sludge is sent into the rotating cylinder by the hollow rotating shaft, it is immediately dumped into the hub cavity under the action of centrifugal force generated by high-speed rotation. The proportion of sludge particles is larger, so the centrifugal force generated is also larger, and it is dumped on the inner wall of the hub to form a solid layer; The density of water is small, the centrifugal force is also small, and only the liquid layer is produced inside the solid layer. The sludge of the solid layer is slowly pushed by the screw conveyor, which is transported to the cone end of the transfer, and is continuously discharged through the outlet around the transfer, and the liquid is discharged from the overflow of the weir four to the transfer, and the centrifuge is collected after the transfer.
When the centrifuge is working, the drilling fluid enters the centrifuge through the feed pipe, and then is accelerated on the conveyor shaft barrel and flows into the drum through the feed hole in the shaft barrel. Due to the extremely high rotational speed of the cylinder, under the action of centrifugal force, the particles with large density or volume are thrown to the inner wall of the cylinder, so that the solid-liquid phase is separated. The solid is sent to the small end of the drum by the conveyor and discharged through the bottom flow port; The fluid containing fine particles flows in the opposite direction to the large end of the drum and is discharged from the overflow port. The thickness of the liquid layer in the cylinder is controlled by adjusting several overflow holes on the centrifuge face. The conveyor can continuously push the settled solid particles towards the small end. When moving to the transition zone of the dry and wet zone of the centrifuge, due to the role of centrifugal force and extrusion pressure, most of the free water is squeezed out, and the adsorption water is mainly left on the surface of the particles. Most centrifuges in the field have a capacity of 40-60m3/h
Note:
Before starting the machine, remove the debris that affects the operation of the centrifuge and check the fastening cover.
Rotate the main motor pulley and auxiliary motor pulley by hand, if there is a blockage phenomenon should be eliminated in time; Check whether the motor running direction is consistent with the indicated direction.
Turn on the power switch, start the auxiliary motor first, pay attention to the normal operation, and then start the main motor, if there is an anomaly should stop to check and eliminate it.
Open the inlet valve and start the liquid supply pump to supply liquid to the centrifuge. If there is no abnormality, the diverter valve should be gradually closed until the full flow. If the centrifuge load is found to be too heavy, the diverter valve can be opened appropriately.
When the solid phase discharged from the centrifuge sand discharge tank is too dry or too wet, the overflow baffle or liquid intake can be adjusted.
When you need to stop, first turn off the motor of the liquid supply pump.
Start the motor of the cleaning pump, and open the valve to clean the inner wall, outer surface, and sand discharge tank respectively, and the cleaning time shall not be less than 60 seconds. (If there is no cleaning pump, it can be cleaned directly with the website water source.)
Turn off the motor of the cleaning pump.
Turn off the main motor and turn off the auxiliary motor after 2 minutes.
Drilling fluid solid control system is an important part of oil drilling engineering, it is responsible for the purification of drilling fluid, to ensure the stability of drilling fluid performance, so as to ensure the smooth progress of drilling operations. In the drilling fluid solid control system, the choice of pipe material is very important, because it is directly related to the corrosion resistance, wear resistance and service life of the system. Here are some common pipe materials: 1.Carbon steel: carbon steel is an alloy steel made of iron as the main component and a certain amount of carbon is added. It is widely used in the pipeline material of drilling fluid solid control system, especially when the conveying medium is oily or less corrosive to steel. Carbon steel has good mechanical properties and weldability, but its corrosion resistance is weak, and it is usually necessary to improve the corrosion resistance by coating or coating.
Stainless steel: Stainless steel is an alloy steel with a chromium content of at least 10.5%, which has excellent corrosion resistance. In the drilling fluid solid control system, when the conveying medium is highly corrosive drilling fluid, stainless steel is often selected as the pipeline material. In particular, type 304 and 316 stainless steels, which contain nickel and molybdenum, can resist the corrosion of gasification and are suitable for offshore drilling environments. (3) Duplex steel: Duplex steel is a special low carbon steel, through the control of the heat treatment process, so that it has an iron surface and austenitic biphase structure. It combines high strength and good toughness with good corrosion resistance. In drilling fluid solid control systems, duplex steel is suitable for applications requiring high strength and good corrosion resistance.
Super duplex steel: Super duplex steel is a kind of duplex steel, but it has higher strength and better corrosion resistance. It contains high chromium, molybdenum and nitrogen content, which significantly improves its resistance to pitting and stress corrosion cracking. In extremely demanding drilling environments, super duplex steel is the ideal pipeline material of choice.
Nickel-based alloy: Nickel-based alloy is an alloy formed with nickel as the main component and other alloy elements such as chromium, molybdenum, copper, etc. It has excellent corrosion resistance and high temperature resistance, especially in environments containing hydrogen sulfide. Nickel-based alloys are expensive and are often used in drilling fluid solid control systems where corrosion resistance is highly required. When selecting the pipe material for drilling fluid solid control system, the following factors should also be considered:
Medium properties: According to the composition of drilling fluid, such as oil, water, sand content, etc., select the appropriate pipeline material.
Use environment: consider the temperature, pressure, corrosion and other factors of the drilling environment, select the corresponding pipeline material.
Cost budget: under the premise of meeting technical requirements, consider the cost of pipeline materials and maintenance costs. To sum up, the selection of pipe material for drilling fluid solid control system is a complex engineering decision, which requires comprehensive consideration of multiple factors.
Since the first set of Kosun solid control equipment entered the domestic market in 2014, Kexun’s products have been highly praised in the country, after years of accumulation, Kexun has accumulated different customer groups at home and abroad. That includes 3 barrels of oil, multiple mud service companies, and environmental companies. Just recently, we received inquiries and orders from our customers. Its demands are as follows
High-frequency drying screen, 4 pieces of the screen, screen using composite material screen.
High-speed variable frequency centrifuge, which uses two-way stainless steel drum material, and the screw discharger is inlaid with a wear-resistant alloy sheet.
The company took into account the particularity of the customer’s project and the relatively short cycle. Finally, we selected the popular model equipment, which has been serving customers for many years and has stable working performance.
one High-performance vibrating screen with a 4-piece composite screen.
High-speed variable frequency centrifuge. Centrifuge can be adjusted from 0-3200, frequency conversion PLC touch screen control. This 360mm diameter centrifuge is the most popular for barite recovery at low or medium speeds; It also provides higher speed for reducing mud weight.
To date, we have sold more than 100 slurry treatment systems and served more than 100 oil RIGS. So far, the customer is very satisfied with the performance of the 363 centrifuges. In addition to the above equipment, kosun can provide a complete product line of solid control equipment, as well as drilling cuttings treatment equipment. kosun’s cuttings dryer, which can efficiently solve the drying problem of oil-based cuttings, has passed the practice certification of many customers at home and abroad and has been unanimously praised. If you need any support, please contact us.
In the oil and gas industry, solid control equipment plays a crucial role in the drilling process. One of the key components of solid control equipment is the centrifuge, which is essential for separating solids from drilling fluids. This process is vital for maintaining the integrity of the drilling fluid and ensuring the efficiency of the overall drilling operation.
Centrifuges are designed to utilize centrifugal force to separate the solid particles from the drilling fluid. As the drilling fluid is fed into the centrifuge, the high-speed rotation forces the heavier solids to settle at the bottom while the lighter fluid is directed out of the centrifuge for reuse in the drilling process. This separation process is essential for maintaining the properties of the drilling fluid, such as viscosity and density, which are critical for successful drilling operations.
The use of centrifuges in solid control equipment offers several benefits to drilling operations. Firstly, it helps to minimize the amount of solid particles in the drilling fluid, which in turn reduces the wear and tear on drilling equipment such as pumps and pipes. This ultimately leads to cost savings and increased efficiency in the drilling process.
Furthermore, the use of centrifuges in solid control equipment contributes to environmental protection by reducing the amount of waste generated from drilling operations. By effectively separating solids from the drilling fluid, the need for disposal of contaminated fluids is minimized, leading to a more sustainable and environmentally friendly drilling process.
In addition to their role in solid control equipment, centrifuges also play a crucial role in enhancing the overall safety of drilling operations. By maintaining the integrity of the drilling fluid, centrifuges help to prevent potential hazards such as blowouts and well instability, ultimately contributing to a safer working environment for drilling personnel.
In conclusion, the role of centrifuges in solid control equipment is indispensable in the oil and gas industry. Their ability to effectively separate solids from drilling fluids not only ensures the efficiency of drilling operations but also contributes to cost savings, environmental protection, and overall safety. As technology continues to advance, the role of centrifuges in solid control equipment will only become more critical in optimizing drilling processes.
1-According to the structure can be divided into desktop centrifuge and vertical centrifuge (floor centrifuge). The separation method can be divided into filter centrifuge and sedimentation centrifuge.
What are the classifications of centrifuges? How to choose? Next, the mud and water separation equipment manufacturers will explain it to you.
1, according to the structure can be divided into desktop centrifuge and vertical centrifuge (floor centrifuge).
2, according to the separation method can be divided into filter centrifuge and sedimentation centrifuge.
3, according to the speed can be divided into low-speed centrifuge, high-speed centrifuge, and super. High-speed centrifuges.
4, according to the capacity can be divided into microcentrifuge (microcentrifuge or mini centrifuge), small capacity centrifuge, large capacity centrifuge, and super capacity centrifuge.
5, whether frozen can be divided into frozen and room temperature centrifuge.
6, according to different uses, centrifuges can also be divided into Medical centrifuge, biological centrifuge, pharmaceutical centrifuge, chemical centrifuge, food centrifuge, dairy centrifuge, milk centrifuge, fat centrifuge, beauty centrifuge, blood centrifuge, blood bank centrifuge, serum centrifuge, plasma centrifuge, enzyme plate centrifuge, special centrifuge, laboratory centrifuge, rare earth centrifuge, mineral centrifuge, pulp centrifuge, mineral powder centrifuge Machine, rock centrifuge, rock core centrifuge, rock centrifuge, coal centrifuge, slime centrifuge, coal tar centrifuge, coal centrifuge, sewage centrifuge, wastewater centrifuge, oil centrifuge, crude oil centrifuge, and oil field centrifuge.
Centrifuge selection
1, can not use vacuum filtration, and requires closed explosion-proof.
2. Good wear resistance of separated mechanical materials.
3, if it is a valuable material, it requires a high recovery rate of centrifuges.
4, when the solid phase material is a crystalline product, the degree of damage of the crystal is required to be low during separation. This has special requirements for the structure of the separation machinery and the discharge methods and methods. For such products, the centrifuge must be selected according to the size and concentration of solid particles in the suspension (or emulsion), the density difference between the solid and the liquid (or two liquids), the viscosity of the liquid, and the characteristics of the filter residue (or sediment).
Centrifuges for drilling generally include high-speed centrifuges and medium-speed centrifuges. 1000-2000r/min is a medium-speed centrifuge, and higher than 2000r/min is a high-speed centrifuge.
The choice of centrifuge is affected by the particle size of the solid phase particles to be separated, the diameter of the centrifuge drum, the highest speed, and the separation factor. The sedimentation centrifuge commonly used on the drilling site is the difference in the density of solid and liquid as the separation basis, mainly used to remove the solid phase material in the drilling fluid of 2-10μm, and is the last level of drilling fluid solid control equipment.
In response to this problem, we should first trek the decanter centrifuge drum speed, of course, within the safety tolerance range, and the material is non-corrosive or less corrosive. Then trudge the filtration area inside the centrifuge drum. The method is to increase the lining mesh, so that there is a small gap between the filter bag and the centrifuge drum, and the trekking permeability; Increase the section area, such as adding V-shaped filter baffles.
In the process of using the decanter centrifuge, the problem of slow dewatering power of the decanter centrifuge is encountered, which is manifested as the increase of solid image material in the drum, the extension of dewatering time of the decanter centrifuge, and the appearance of non-drying. This phenomenon belongs to the general phenomenon.
It can be a few times dehydration methods, reducing the amount of centrifuge dehydration filter material per time, more, less discharging method. If the material is sticky, wash it within the limits allowed by the process. Trudging solid phase material particle size, in the case of unchanged process, if you want to trek fear rate, you can consider increasing, such as adding flocculant.
Decanter centrifuge is one of the widely adaptable solid-liquid separation equipment on the market, mainly used for solid-liquid separation. When selecting the equipment, it depends on the specific condition of the material, the separation or not of the decanter centrifuge and the separation function are determined by the dryness of the solid particles in the suspension, such as salt and sugar and other water-soluble items, which need to be separated after using flocculant.
Kosun_decanter centrifuge is mainly composed of a drum, screw, differential system, liquid level baffle, drive system, and control system. It is a special equipment for solid-liquid separation designed according to the characteristics of petroleum drilling fluid, which can complete various processes such as feeding, centrifugal sedimentation, and unloading at full speed. It is mainly used for recovering barite, removing fine solids, reducing the solid content of drilling fluid, controlling the density and viscosity of drilling fluid, ensuring the performance of drilling fluid, and playing an important role in rapid drilling. The LW series centrifuge separates the drilling suspension by the principle of centrifugal sedimentation. The suspension enters the rotary drum from the feed pipe through the liquid outlet hole in the screw pusher. Under the action of centrifugal force, the solid particles are pushed to the inner wall of the rotary drum and discharged through the slag discharge port at the small end of the rotary drum through the blade on the screw pusher. This is repeated to achieve the purpose of continuous separation. Sedimentation centrifuge belongs to the category of horizontal spiral centrifuge, full name horizontal spiral sedimentation centrifuge. Factors affecting the use effect of decanter centrifuge
The use effect of decanter centrifuge, the impact of its mechanical part is divided into adjustable factors and non-adjustable factors, now respectively explained, first understand its principle of action, you can effectively control it in use
1, non-adjustable mechanical factors are drum diameter and effective length. Half cone Angle of the drum. Pitch. The following categories are described: drum diameter and effective length: The larger the drum diameter and the longer the effective length, the larger the effective settling area and the greater the processing capacity. Half cone Angle: When the sediment settling inside of the centrifuge drum is pushed to the discharge port along the end of the drum cone, it is subjected to the downward sliding reflux force due to the action of centrifugal force. Drum half cone Angle: a more important parameter in centrifuge design. In terms of clarifying effect, the cone Angle should be as large as possible. In terms of slag delivery and dehydration effect, the cone Angle is required to be as small as possible. Pitch: that is, the distance between two adjacent spiral blades, is a very important structural parameter, which directly affects the success or failure of slag transport. When the spiral diameter is fixed, the larger the pitch and the larger the spiral lift Angle, the greater the chance of the material being blocked between the spiral blades. At the same time, the large pitch will reduce the number of turns of the spiral blade, resulting in uneven material distribution at the end of the drum cone, resulting in increased vibration of the machine. Therefore, for difficult-to-separate materials such as activated sludge, slag delivery is more difficult, and the pitch should be smaller. Spiral type: According to the liquid and solid relative movement in the drum is divided into countercurrent and forward flow. The feeding chamber of the countercurrent centrifuge is in the middle of the spiral, that is, near the boundary between the dry zone and the settling zone, to ensure that the liquid phase has enough settling distance, but the solid phase can only stay for the time required to pass through the cone, so a higher centrifugal force is required; The material entering the drum from here will cause the settled solid particles in this area to float again due to disturbance, and will also produce turbulence and additional eddy currents, which will reduce the separation effect. 2, adjustable mechanical factors are drum speed, difference speed (difference ratio), liquid ring layer thickness, and process factors, the following categories are described: drum speed: drum speed adjustment is usually achieved by variable frequency motor or hydraulic motor. The higher the rotational speed, the greater the centrifugal force, which is helpful to improve the solid content of mud cake. However, excessive rotation speed will destroy the sludge flocculation, but reduce the dehydration effect. At the same time, the higher speed has high requirements for materials, the wear of the machine increases, and the power consumption, vibration, and level will also increase accordingly. Difference velocity (difference ratio), the difference velocity directly affects the slag discharge capacity, mud biscuit degree, and filtrate quality to improve the difference velocity, which is conducive to improving the slag discharge capacity, but the sludge dehydration time will be shortened, the water content of the mud cake after dehydration is large, and too large difference velocity will increase the disturbance of the spiral to the liquid pool in the clarified area, and the filtrate quality is relatively poor (commonly known as “back mixing”). Liquid ring layer thickness: liquid ring layer thickness is an important parameter for equipment optimization, which directly affects the effective sedimentation volume of the centrifuge and the length of the dry zone (bank zone), and then affects the treatment effect of sludge dehydration. Generally, it is achieved by manually adjusting the level of the liquid level baffle in the shutdown state, and the adjustment must ensure that the level of each level baffle is the same, otherwise, it will cause severe vibration when the centrifuge is running. The increase in the thickness of the liquid ring layer will increase the settling area, the residence time of the material in the machine will also increase correspondingly, and the quality of the filtrate will be improved, but the length of the dry zone (bank zone) at the same time will be shortened, resulting in the reduction of the mud biscuit degree. On the contrary, lower liquid ring layer thickness can obtain higher solid content of mud cake, but at the cost of filtrate quality. Process factors: To improve the sludge dewatering performance, an appropriate amount of organic polymer flocculant, such as polyacrylamide (PAM), should be uniformly added before mechanical dewatering to reduce the specific resistance of the sludge, so that the sludge solid phase and liquid phase separation is easier to dehydrate, and the type of flocculant must be adapted to the characteristics of the sludge and the type of equipment and operating conditions. In many cases, the agent with better performance in the flocculant selection beaker test does not have better performance in practical applications, and the important reason is that although the agent characteristics meet the sludge characteristics to a certain extent, it cannot fully meet the operating conditions of the equipment.
Many factors affect the dewatering effect of decanter centrifuge, and all factors affect each other, so the treatment effect is the result of the comprehensive action of the above factors, the selection of centrifuge should be combined with the actual situation of the project, the adjustment of operating parameters should be considered from the expected mud cake moisture content, solid rate and economic factors required by the disposal method of the mud cake after dehydration
