Category Archives: Vacuum Degasser

NOV(National Oilwell Varco)Nov Brandt Solids Control Division Is very famous brand around the world.

Vacuum degassers mechanically remove entrained gases such as hydrogen sulfide, carbon dioxide and natural gas from the mud system. Entrained gas can reduce the hydrostatic head of the mud column and can cause catastrophic well control problems.

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BRANDT™ manufactures negative pressure (vacuum) and atmospheric degassers. Vacuum degassers utilize negative pressure to withdraw entrained gases from the mud. In order for this to work, mud is pumped through a venturi, which develops a negative pressure, thus sucking mud into the unit. The mud then flows over dispersion plates, arranged either horizontally or vertically, creating thin sheets of gas-cut mud.

But now there are many Chinese manufactures can produce the vacuum degasser same like Brandt. DC Solids Control Is a China based Solids Control equipments manufacturer, we also offer worldwide vacuum degasser and services.

vacuum degasser

Our vacuum degasser is constructed by main vessel, gas water separator, vacuum pump, motor, and eletric control cabinet. The vacuum degasser could be used in many field, like commercial uses, agricultural uses and oilfield uses. Hereunder we talk about the oilfield uses.In oilfield drilling fluid system, there are 2 types degasser. One is poor boy degasser separate large quantity invaded gas, the other is the vacuum degasser, we also call it gas buster.

The vacuum degasser is a high-efficiency in-line modele that removes dissolved gasses from HPLC solvents. Its unique design assure reliable continuous operation and the highest level of continuous performance available without the need for helium degassing. Up to five solvent lines may be degassed simultaneously by one unit. The extremely low internal volume of each teflon AF channel offers very quick equilibration and very short startup times compared with PTFE degassing channels which have the same degassing efficiency.

vacuum degasser

A vacuum is pulled on a stream of water, and the vacuum draws the dissolved gas out of solution, removing it from water. There are two basic systems available – tower and membrane. In a vacuum degasser tower, water flows by gravity down through a tower filled with packing as a vacuum is drawn on the tower. The packing in the tower has a very high surface area, disperses the water very effectively, thereby enhancing the removal of O2, CO2 and N2. Performance is further enhanced by using atomizing nozzles as the water enters the tower. In a membrane degasser, water flows across one side of a membrane surface while a vacuum is drawn on the other side. Both types of systems use steam jet eductors or liquid ring pumps to generate the vacuum required.

VACUUM DEGASSING PROCESSES :

Vacuum degassing is practiced in the steel industry for several purposes. They are :

to remove hydrogen
to improve cleanliness by removing part of the oxygen
to produce steel of low carbon content ( < 0.03%)
to produce steels to close chemical composition ranges (including deoxidizers), and
to control pouring temperatures, especially for continuous casting operations.

Vacuum degassing is the process of removing dissolved gas from a liquid solution by lowering the pressure inside a vessel containing the solution. The reduced pressure inside the vessel causes the gas to become less soluble and separate from the liquefied material. After the vacuum degassing process is complete, the gas is removed from the vessel, and the pressure is returned to normal. This process is typically performed in a specially designed chamber known as a vacuum degasser. Vacuum degassing is often utilized in water treatment, laboratory testing, and soil purification procedures.

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Operational Theory:

Vacuum degasser utilize negative pressure by vacuum pump to withdraw entrained gases from the mud. In order for this to work, mud is pumped through a venturi, which develops a negative pressure in the vessel by vacuum pump, thus sucking mud into the unit. The choice between horizontally- or vertically-mounted units is typically based on the footprint requirements of the specific rig.

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Commercial uses
Vacuum degassers are used in some water treatment operations to significantly reduce the total gas pressure in water containment vessels. The vacuum is created by using either a blower or pump, and the degasser containment vessel is constructed from several materials, including steel, fiberglass and aluminum. Some containment vessels are built from concrete reinforced with metal fittings. Aqua vacuum degasser are often used to remove sulfur gases that can build up in water.

Function of vacuum degasser 

Vacuum degasser used in filling well, grinding well and sinkiang Di na well. All technology indexes all achieve the design requirements. Degassing effect is marked and will produce the good economic benefit. In the regular drilling process, if occur drilling fluid gas cutting, the vacuum degasser can dispose it. It can avoid the influence of gas cutting to drilling fluid working performance, decrease the abrading of mud pump, improve the efficiency of water and decrease the repairing times and stop drilling dispose times.

Comprehensiveness of vacuum degasser 

In unbalanced drilling, now have the degassing equipment – drilling fluid gas separator, it only separate the free gas in drilling fluid, but it can’t eliminate the not free gas. Drilling fluid often have gas cutting. The function of vacuum degasser is eliminating the not free gas. The equipment developed succeed provide the guarantee for the matched equipment of regular drilling and unbalanced drilling.

Why vacuum degasser can eliminate the gas 

In order to efficiency eliminate the gas in drilling fluid must meet the requirements:

The bubbles in drilling fluids should expose on the surface, will rapidly swell and fracture in the negative pressure condition. Gas cutting drilling fluid will remain a certain times in separation chamber. After gas cutting enter into separation chamber will present the turbulent condition flowing. So the degassing effect decided by the reasonable control of vacuum, the remaining times of gas cutting drilling fluid in degassing chamber and the turbulent condition in degassing chamber.

Degassing chamber vacuum is higher, the bubbles received the expansionary force in drilling fluid is bigger, the volume expansion is bigger, drilling fluid give the buoyancy is bigger, then bubbles are easy float to the drilling fluid surface to broken.

ZCQ/3 vertical type vacuum degasser used to remove the bubbles whose diameter less than 10mm. It uses level centrifugal force field and negative pressure dual function action principle to eliminate it, the throughput is 180m3/h, the degassing efficiency is 95%-99%, it can effectively remove the gas invaded in drilling fluid, avoid the well kick, blowout and blindness aggravate drilling fluid evocable well leakage accidents.

Structure of vacuum degasser 

ZCQ/3 vertical type vacuum degasser made of explosion proof motor, vacuum pump, coaxial shunting gear reducer. When works, pressuring the start key, motor drive vacuum pump and mud gas separator degassing impeller rotate, gas cut invaded drilling fluid absorbed to mud gas separator and throw to mud gas separator by degassing impeller. Production a fluid lamina which is eddy spiral movement and form the centrifugal force field. Because the centrifugal force is the 32 times of its gravity, make the small bubbles in fluid lamina rapidly buoyancy lift to surface, in the function of negative pressure, the small bubbles rapidly broken, the broken bubbles gas enter into vacuum pump and discharged through the two air holes in reducer.

Vacuum Degasser Parameters

Model ZCQ240 ZCQ270 ZCQ300 ZCQ360
Main Diameter 700mm 800mm 900mm 1000mm
Treating Capacity ≤240 m3/h ≤270 m3/h ≤300 m3/h ≤360 m3/h
Vacuum -0.030~-0.045MPa -0.030~-0.050MPa -0.030~-0.055MPa -0.040~-0.065MPa
Ratio 1.68 1.68 1.68 1.72
Efficiency ≥95%
Motor Power 15kw 22kw 30kw 37kw
Vacuum Power 2.2kw 3kw 4kw 7.5kw
Dimension 1750×860×1500 2000×1000×1670 2250×1330×1650 2400×1500×1850
Weight 1150kg 1450kg 1800kg 2100kg

Characteristics 

The volume is small, light weight, structure impact and simple. The design of vacuum degasser use electromotor, vacuum pump, reducer, degassing long impellers and pump impellers equipped in the same shaft in series, and the reducer is coaxial shunt type drive structure, make input axis and output shaft in the same axis, offset the lateral thrust, the lengthways structure size can be shorten.

Installation, operation and maintenance is convenient.

Power is small, degassing efficiency is high, treating capacity is big. The degasser treating capacity is 180m3/h, can dispose the drilling fluid of drilling pump double pumpage at the same times, the treating capacity follows the liquid height to automatic control , when use needn’t do any adjustment.

Barrier- free long working hour, can be as the agitator agitate drilling fluid, also can replace centrifugal pump

Vacuum degasser can wipe off the invaded gas from drilling mud quickly, restore drilling mud proportion, keep mud viscosity performance and improve the quality of drilling fluid. Vacuum degasser produced by DC Machinery has the advantages of compact structure, reasonable design and so on.

Function of vacuum degasser 

Treatment gas invaded drilling fluid, wipe off the bubbles in drilling fluid, recover gas invaded density.

The difference of vacuum degasser and mud gas separator

The main function of mud gas separator is eliminating the big bubbles in drilling fluid which refers the expansion gas in well eye annular air, the diameter is about 3-25. The fluid can directly enter into mud gas separator from rotating blowout preventer, also can enter into fluid from throttle manifold place, separate out the big bubbles. The treatment drilling fluids still have small bubbles, after through shale shaker enter into vacuum degasser to treat.

Vacuum degasser is used to eliminating the small bubble sin drilling fluid, main used to wipe off the bubbles whose diameter is smaller than 1mm.

Consist of vacuum degasser 

Vacuum tank.  Three ventilation control valve system.  Ejector system.  Water circulating type vacuum pump.  Water box.  And Foundation

Vacuum degasser produced by DC Machinery is suitable for various supporting of drilling mud solids control system, it plays an important role in restoring drilling mud performance, and can also be an agitator with big power. 

Checking routine every day

Checking the connection condition of vacuum pipe

Check gas outlet pipe and the connection.

Checking mud outlet pipe whether unimpeded, discharged pipe outlet must be submerged below mud surface.

Check oil pool liquid level.

Check gas discharge value.

Starting degassing 

Check all electrical equipment connection.

Starting degasser

Degasser must gradually enter into normal working condition. check mud discharge pipeline.

Stop degasser

Stop the vacuum degasser

Open the washing value, washing separation impeller 5 minutes.

Check and maintenance of ever week 

A Speed changing box

Check speed changing oil pool every day, on occasion add Dexron III transmission fluid.

B Top washing device.

We must washing vacuum degasser every week, washing out the mud which dry and hard the vacuum chamber. Make the sufficient number of seawater wash the impeller of upper gas cell.

C Other maintenance

Gear case oil, work with 1000 hours should replace lubrication and cleaning or replace filter assembly. The model of lubrication is Dexron III fluid frivr , oil volume is 2 gallon and the liquid level is 25/64 on galss porthole.

Day time maintenance

Check the inner surface of wear- resisting rubber cone bush.

Check inlet pressure whether meet the demand, ensure small hole is cleaning and give it fair adjustment.

Lubricate the packing of desander pump and desiltr pump.

Three months maintenance

Add the butter to coupling.

Two years maintenance or using 15000 hours maintenance

Check pump impeller, pump case and sail upstream, discharge water valve, when need should replace impeller, pump case or value

Check the bearing and sealing element, when needed should replace.

Check hydrocyclone cone bush and each component, when needed should be replaced.

 

There are mainly have two reasons why vacuum degasser use vacuum pump, the one is, the degassing mud in degasser absorb to the top of the degasser, make if form into thin layer flow on baffle, vertebral body or between hopper;The second one is the gas discharged in tank and intake air is all discharged. Vacuum pump also can produce a kind of pressure which can discharge the exhaust gas through a pipeline.

The degassers are used to clean the gas in the drilling fluid, to ensure the drilling fluid property relatively stable, to guarantee the steady operation of swirlers. The degassers can be grouped into two kinds: ordinary pressure type and vacuum type.

The ordinary pressure degasser is to use the centrifugal to take out gas to invade the mud, with the help of centrifugal force to make the mud spraying in the jet tanks and striking on the wall to make gas releasing. The vacuum degasser is to use the suction of the centrifugal, forming negative pressure in the vacuum tanks, under the action of drilling fluid at atmospheric pressure, through the suction pipe into the hollow shaft, then by umbrella piece of around the hollow shaft assembly, they jet to the skin of tank.

The Spirovent Superior is a fully automatic vacuum degasser for heating, cooling and process installations. This device temporarily subjects part of the installation fluid to low pressure or vacuum. As a result, the air dissolved in the fluid is released and removed from the system. Thanks to the electronic, independent control system, reading system information is a breeze.

Vacuum degasser use atmosphere and vacuum degassing theory eliminate the remaining gas in drilling fluid. Vacuum degasser tank is installed a group of wave blade and many mud inlet make flow is uniform distribution and form into turbulence in tank.

The throughput of vacuum degasser is 500g/m, 1200 type is 1200g/m, this is because the different area of wave blade. The blade area of vacuum degasser is 500 times of 500 type which is in order to ensure effective eliminate the remaining gas.

The vacuum tank produce low pressure in tank, the bubbles in the mud can well discharge. According the change of overload, vacuum pump proof motor can be adjusted. The mud liquid level in bottom tank feedback to a group of mechanical transmission device in order to automatic control inlet displacement and vacuum tank liquid level. Jet pump sucks out degassing mud from vacuum degasser tank.

Design characteristic

Drilling fluid enter into vacuum degasser from the inlet pipeline of tank wall. After gas is discharged from mud, flow to the bottom of vacuum tank. Degasser use vacuum and molecular collision / turbulence theory and maximize the surface area of drilling fluid to eliminate the gas.

Low pressure — the low pressure in vacuum tank make the bubble in mud is nature swell. It is more easy float to the surface of mud after bubbles is large and escaping mud.

Collision/ turbulence – the mud flow to the centre of tank and spray out from the ostioles which are in the wall of the tank. The liquid has enough force to impact the blade and tank wall. The result is the remaining gas is more easy escape to vacuum environment. The probability is big of blade is cracked.

Contacting area is maximum — in the process of mud splash to the tank from the odtioles in vertical pipe, the mud through a group of wave plate fine and thin blade make mud is disperse to increase the contacting area of the mud and vacuum environment. The residual gas is more easy to discharge.

Operation theory of vacuum degasser

Drilling fluid is transported to mud inlet from mud tank. Mud through degasser vacuum is bout 29inch of mercury is absorbed to vertical pipe. The mud splashes to wave blade and tank wall from the spray mouth of vertical pipe, the gas evolution this time and expose in the low pressure environment which is extracted by out tank vacuum pump.

The degassing mud ceaseless flow to bottom mud pit from blade group. Centrifugal pump is unceasing extract degassing mud by ejector.

DC Solids control manufacturer combines the advanced technology at home and abroad to design the high quality vacuum degasser. You can be assured that our products are of the quality you expert.

The common basic theory processing gas cut

Gravity separation

Gravity separation is decided by the difference of density, the height of liquid column, the size of bubbles and the flow resistance in fluid. The simple drilling fluid tank or fracturing tank is a gravity separator, it can store fluid, solid phase and gas until they are natural separation. The gas rise and escape from the top of the tank, the oil is separation in other fluid and floating to the top of fluid. When oil over overflow mouth or built-in baffle of the tank is siphoned off, drilling fluid and other fluid are eliminated from the bottom tank. Gravity separation is the main method of used in oil-water separation than and seal type confined separator.

Centrifugal separation

Drilling fluid is sent to the circular container with tangential or cylinder container. Oil, gas, water and solid phase particles produce the artificial gravity by the centrifugal force of a rotating fluid. The method is used in many open or West Texal separator, but the involute spiral is widely used in seal type bearing system, it produces gravity separation.

Impacting, baffling, spray separation

Impacting, baffling, spray separation make drilling fluid impact the baffle with high speed, the separation the gas. It can directly separate the drilling fluid which is discharging from overflow pipe and chip removal pipe, it can separate after using pump increase the drilling fluid flow speed.

Parallel-plate and membrane separation

Parallel-plate and membrane separation is aim at the gas of drilling fluid. Drilling fluid is tile expansion on parallel plate, make gas is easy to escape. In parallel separator, the drilling fluid has gas is forced between the two parallel plate, male bubbles distortion, the thin film processing is used in most vacuum degassing device. 

Vacuum separation

Vacuum degassing device is using separate the drilling fluid mixed gas, it using decrease pressure to urge bubbles swell and fracture. The method is used in degassing device to eliminate the drilling fluid mixed gas.