Category Archives: Hydrocyclones

Introduction of the desander cones for solid control

Desander is used as the 2nd stage of solids control for drilling fluids, which makes separations between 45 and 75 μm. DCCNQ Series Desilter is used as the 3rd stage of solids control for drilling mud, which makes separations between 15 and 45 μm.

Usually the cone diameter is more than 6″is called Desander, and used as the second-control equipment in drilling operation. We commonly used 8 “and 10” cones desander to separate solid-phase particle size 47-76μm in the drilling fluids.

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SONY DSC

Desander, as stated earlier, have no moving parts. The larger the internal diameter (ID) of the desander is, the greater the amount of fluid it is able to process and the larger the size of the solids removed.

Desander (10 in.cone) are able to remove roughly 50 percent of those solids within the 40-50 micron range at a flow rate of 500 gallons per min (gal/min), while desilter (4 in. Cone) are able to remove approximately 50 percent of those solids within the 15-20 micron range at a flow rate of 60 gal/min. Micro fine separators are  able to remove around 50 percent of those solids within the 10-15 micron range at a flow rate of 15 gal/min.

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Desander is typically positioned next-to-last in the arrangement of solids control equipment, with decanting centrifuge as the subsequent processing unit. Desander are preceded by gas busters, gumbo removal equipment (if utilized), shale shakers, mud cleaner (if utilized) and vacuum degasser. Desander is widely used in oilfield
drilling.

Proper hydrocyclones used in mud recycler system

In addition to the shale shakers, another way to size the processing capability of the mud recycler is to look at the hydrocyclone. Depending on the size of the mud recycling system, cone size will be 4, 5, 10 or 12 in. Each size cone has a micron “cut point,” and represents the size of the smallest particle the cone can “pull.”

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SONY DSC

Four- and 5-in. cones have a 20-micron “cut point,” and 10- and 12-in. cones have a 74-micron “cut point.” Smaller mud systems normally have two section tanks, with a ”dirty” tank under the scalping shaker and a “clean” tank under the mud cleaner (shaker with desilting cones), while larger systems can have three section tanks with scalping, desanding and desilting.

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SONY DSC

One hydrocyclone processes liquid at a rate of 50 gpm/ 4-in. cone, 80 gpm/ 5-in. cone, and 500 gpm/ 10-in. or 12-in. cone. Some manufacturers’ volume amount for their respective cone sizes may differ than those cited herein, but these are the most common within the industry for reference purposes.

Maintaining proper pressure is essential for the hydrocyclones to work effectively, with the normal operating pressure range for 4- and 5-in. cones of 30 to 40 psi; 10- and 12-in. cones of 23 to 35 psi. Pressure above 45 to 50 psi cause premature internal cone wear, and lower pressure down around 20 to 22 psi is a “red flag” that you better consider rebuilding the centrifugal(s) to maintain pressure in the optimum range.

Common underflow problems of drilling fluid cleaning Cyclone

When cyclone works, high-speed swirling movement generates the air column and low-pressure area, creating suction towards underflow outlet. Inject some water into cyclone by certain pressure and adjust the outlet till it allows no fluid flow, meaning it reaches the balance point. This cyclone is called balanced cyclone, often found in mud cleaners where solid-content fluids enters and solids leave through underflow outlet.

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However, some problems may arise adjusting the underflow outlet:

1. “Dry Underflow”: Relatively smaller outlet can pile a layer of dry silt between it and the balanced point. When ultra-fine solids enter, its water goes through the layer and dewatered solids block the outlet, causing dry plug. And this is called “dry underflow” adjustment.

2. “Wet Underflow”: Relatively larger underflow outlet can discharge conical rotating liquid. And this is called “wet underflow”.

3. “Radial” Discharge: Commonly, two flows move mutually reversely at the apex, one is the air inhaled and another the solid-content slurry discharging radially, forming an annular curtain there. Inhaled air keeps the outlet open and the cyclone efficient.

4. “Rope-like Discharge”: When the solid content excessively exceeds the designed capacity, the cyclone is over-loaded and solids flow out outlet in a rope-like shape, making no air or annular curtain but a nozzle possible. Then, some solid phase within limits will turn around and out from vortex finder.

How to do when sand block the hydrocyclone

The work principle of hydrocyclones is to separate two or several components with different densities with the aid of centrifugal force. After the mixture is sent into hydrocyclones by certain pressure, it gradually flow into a high-speed rotation where the heavy phase form an outer swirl by moving downwards along the axis, outwards along radial direction, downwards again along the cone till they flow out of underflow; while the light phase form upward inner swirl by moving towards axis and upwards till they go out from overflow outlet. Thus, the separation is done.

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Sand fill is the commonest anormaly to hydrocyclone and is categorized as:

Sand fill at the underflow: it happens as a consequence of improper adjustment that results in dry bottom or of excessive silt content which brings about overloaded hydrocyclone. It should be removed immediately as it affects the purification ability and accelerates abrasion of lining and vortex tube. Usually the best ways are to enlarge underflow outlet or to have more solids taken away by preceding equipment.

Sand fill at the inlet: it can be partial or overall. Partial sand fill decelerates fluid flow inside inlet, leaks enormous drilling fluids from underflow and sometimes clean mud which may flow backwards from the overflow as, at that time, hydrocyclone is not more functional than a hopper. Overall sand fill is prone to back flow drilling mud from the overflow. Inlet sand fill generally stems from poor drilling fluids management, and most likely from going round the shale shaker or abrading shaker screens.

Scientific selection of hydrocyclone for desander and desilter

Abrasive resistance is the mainly quality target of the cyclone, and the separation size which also called D50 is the mainly performance of hydrocyclone, the lower the D50, the better the separation efficiency of the cyclone. In the desander, desilter configuration should pay attention to the particles separation range not only have a certain distance, but also have a certain degree of overlap.

According to the classification standard and separating size of hydrocyclone. The inner diameter of the cylindrical casing for diameter 150 – 300 mm, separation size of 74 – 44μm of the water cyclone were drilling fluid desander; the inner diameter of the cylindrical casing for phi 100-150, the separation granularity for 44 – 15μm of the water cyclone for desilter. But the separation size of the desander and desilter in the field maybe colse (drilling fluid desander for 20 – 50μm, desilter for 45 – 15μm), after the drilling fluid processed by desander then it processed by desilter, resulting in the desilter can’t have effect on removing solid particles . The main reason for the above phenomenon is that the manufacturing level of the cyclone is not up to the requirements, and the effect can not be hit by the drilling process. So many users choose the macthing scheme of 2 sets of drilling fluid desander instead of 1 set of drilling fluid desander and one desilter.

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Some users simply install second sets of drilling fluid desander in place of desilter mounted, the process will not change. This method is not desirable, since the performance parameters of the two sets of drilling fluid desander are the same, it should be using parallel process, to mutual standby or fast drilling in increasing the processing capacity of the drilling fluid. But for the well with high requirements of the drilling fluid performance, the reasonable supporting scheme is still supporting one set of drilling fluid desander one desilter, using the series process.

In the selection the desander and mud desilter should choose products with different separation particle size range, such as desander separation size range for 40 – 60μm, separation size of desilter s for 15 – 45μm, then it can achieve better treatment effect.

Present situation of driling mud cyclone

Desilter  is usually comprised by 8-10 cyclones. In addition to that, most of them has the structure of linear arrangement and one side of liquid inlet, this structure usually easy to cause different inlet pressure of desilter and the operation is not stable, and vertebral body of the desilter is fragile, short life, drilling fluid is often not up to the requirements of the effect.

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The desander cycclone cones needs to be improved in corrosion resistance, high temperature resistance, wear resistance and ageing resistance performance, the use of it has frequent replacement. Although the manufacturers use the high chromium cast iron, rubber lined, polyurethane liner and medium manganese wear-resistant ductile iron and other materials, but the effect is not ideal. For recovery of all drilling fluid discharged from underflow, desander are usually equipped with small drilling fluid vibrating screen, most of which adopt the motor belt wheel driving, but there are problems of instability of eccentric shaft excited vibration, the maintenance is not convenient and the service life of the screen is short etc.

The cyclone produced by Dachuan Machinery Equipment Co., Ltd. adopt special wear-resistant polyurethane material, which is corrosion resistance, wear resistance, high strength and reasonable in price. The cyclone has inlet tangential feeding, smooth inner surface, high separation efficiency. And it is equipped with automatic anti sand block device and adjustable underflow hole device. The inlet and outlet of the cyclone produced by DC are connected by clamps, fast, safty and reliable.

Common malfunction of cyclone underflow on drilling mud cleaner

When the cyclone during normal operation, the air column is formed in the center of the spiral movement, resulting in a low pressure area which has a suction on the underflow. Under a certain pressure, clean water is pumped into the cyclone, and adjust the underflow orifice size until there is no liquid discharged from the underflow, and at this time size of the underflow mouth is the equilibrium point, this type of hydrocyclone are known as balance cyclone. The cyclone is most used for drilling mud cleaner, when pump the liquid containing solid into it then solid phase will be discharged from the underflow.

Contact us if you want purchase the cyclone or mud cleaner like this!

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Several phenomena may appear on the regulation of hydrocyclone underflow of drilling mud cleaner:

1. ‘Dry bottom’: if the underflow orifice is adjusted smalller than the equilibrium point opening, a layer of dry heap shaped sand will appear between the equilibrium point and the actual underflow openings. When using this type of hydrocyclone to separate the very fine solid, the fine particles being separated lose surface water film when being through the sand layer, resulting in the underflow opening is blocked, and make the formation of “blocking”, this regulation is called “dry bottom” regulation.

2. ‘Wet bottom’: if the underflow orifice is adjusted to larger than the opening of balance point, heap shaped rotating liquid will be discharged, this regulation called “wet bottom” regulation.

3. ‘Umbrella’ discharge: in the normal work, there are two fluid flowing relatively at the underflow: one is inhaled by air, another is the thick slurry containing solids that descharged as umbrella shape, then the annular barrier formed at the opening place. Inhaled air flow maintain the smooth flow of the underflow opening to ensure the cyclone working at peak efficiency.

4. ‘Rope’ discharge: when the solid content is too large in the feeding matrials, when the solid content to be separated exceeds the maximum allowable displacement of drilling mud cleaner cyclone, “overload” will generate. The underflow discharge from the bottom in a rope shape at this time. The air will not be sucked here, and there is no ring block at the opening bottom, but the formation of a choke nozzle will be made. In this case, many of the solid particles that are in the range of the clearance will be folded to the overflow pipe and return to the drilling fluid system.

Working pressure regulation of cyclone of DC Machinery

The pressure difference between inlet and outlet of the cyclone, which is working pressure, is one of the important working parameters. Increasing the pressure difference of the inlet and outlet, in fact, increases the flow rate of the liquid, so that the time of the liquid in the hydrocyclone is less.

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Since the time of the liquid in the hydrocyclone is basically the separation time of the solid phase, the residence time is reduced, and the separation process is not sufficient.

Moreover, due to the reduction of residence time, the wear of the cone can be accelerated. Reduce the export pressure, resulting in the decline of the swirl velocity, centrifugal force is not enough, despite an increase in the liquid residence time in the cone, also cannot achieve full separation effect. Therefore, cyclone will have an optimum working pressure.

DERRICK Company cyclone characteristics

DERRICK comapny supply the top quality hydrocyclones, what characteristics do they have? DC machinery will answer you.

DERRICK company’s cyclone has the following characteristics :
1 desander desilter , shaker together to form a complete set of mud cleaner system , saving floor space, reducing the transport trips .
2 ring desilter provided to each funnel same working pressure, so that the cyclone achieve optimal performance.
3. ¢ 101.6mm cyclone use of lightweight , high corrosion polyurea amine resin , has a long life and easy maintenance advantages , replaceable bottom orifice nozzles can reduce the loss of drilling fluid .
4 each are equipped with cyclone inlet shut-off valve , even in working condition but also on individual funnel overhaul, removed.
5. ¢ 101.6mm integrated desilter lower ceramic liner , greatly increasing the corrosion resistance .
6 desander on a pallet can be flexibly installed 1 to 3 Desanding funnel . Each ¢ 254mm Grit funnel 22.86m drilling fluid under pressure head capacity of 1.9m3/min. Maximum capacity of 5.7m3/min. Effluents discharged directly or streaming only shaker for further processing.
7 desilter can choose 8,10,12,16 or 20 funnel , funnel processing capacity of each 175L/min.
8 Recycling drilling fluid shale shaker motor is large capacity and very detail mesh shaker,can be used in parallel with the main shale shaker .

DC machinery is top China solids control service company, we provide cyclones/ hydrocyclones ,manufacturer desilters, desanders and mud cleaners of all types, welcome inquiry us for more information.

What is hydrocyclone?

Hydrocyclone is a part of desander or desilter. Desander and desilter are solids control equipment. Hydrocyclone raw material is high wear-resistant polyurethane , it have the advantages of well performance, long service life, low price.

Hydrocyclones are common industrial and manufacturing process separators used to remove solids from carrier liquids or to separate liquids of different consistencies. They are simple yet efficient devices with no moving parts and requiring very little maintenance. Commonly known as cyclones, these devices are generally constructed of steel, ceramics, or abrasion resistant plastics. Typical uses of hydrocyclones are removing contaminates from paper pulp, separating of oil from water, extracting metal shavings from cooling liquids, and starch recovery from waste water in potato processing facilities. Cyclones are also found in the mining industry processing plants to separate process solids from water.

A hydrocyclone is a filter or separator mechanism that uses centrifugal force to separate solids from liquids or even liquids of different consistencies. The hydrocyclone consists of a two-part chamber with a inner profile which is cylindrical along its upper section and conical along the lower half fitted with one entry and two exit points. When a suspension is pumped into the cyclone, it spins around the inside of the chamber creating a centrifugal force which causes suspended solids to separate from the liquid carrier. The filtered water and solids then exit the hydrocyclone, typically at opposite ends. Hydrocyclones are used extensively in industrial and manufacturing sectors and are suited for liquid rich suspensions carrying solids heavier than the fluid.

Want to know more parameter and price, contact DC machinery . mail : dc@dcmudcleaningequipment.com