Author: gnadmin

In many industry applications, it is often the case that solids materials are mixed with liquid. For instance in water well drilling process there is a lot of slurry. Dumping will contaminate environment and waste a lot of water, and it may damage landscape. Under this circumstance, decanter centrifuge will play a very important role to separate solids from liquid. Without decanter centrifuge, solids/liquid separation will become low efficient, high cost and waste of liquid because of low separation efficiencies in other means of separation.

The mostly commonly used decanter centrifuge horizontal type. They work under the principle of gravitational separation. Let us take an example. If you fill a container with mud and liquid. The weight of the mud will cause it to settle down to the bottom of the container. The aggregation of the solids on the base of the container will force liquid to stay on top of the solids, generating a obvious barrier between solids and liquid. The longer the mud is undisturbed in the container, the clearer the liquid is.

Decanter centrifuge uses the same principle of gravitational force. The difference is that decanter centrifuge formulates a much stronger gravitational force, which is usually 500 to 5000 time the regular gravitational force, which greatly reduce the time for solids to settle down, and the sizes of smallest particles decanter centrifuge can remove.

Rotational separation can be found in many area, from amusement parks to country county ground. Rotating horizontally gives you a force to overcome gravitational force from the earth. Decanter centrifuge works the same way, except that the rotation can be vertical, causing solids to move in radial direction, not in horizontal direction as we see in amusement park. The other thing is that decanter centrifuge rotates in much higher RPM, usually in a few hundreds RPM. Small centrifuges can run at the speed of over 10,000 RPM.

Drilling fluid is critical for the safely operation of drilling activities, the protection of reservoir and the success of oil and gas investment.

Because the importance of drilling fluid, a good amount of research and development work have been conducted to enhance the performance of drilling fluid. Many kinds of additives are added to drilling fluid to turn the property of drilling fluid to meet the needs of certain drilling jobs. Oil based drilling mud is one of the major kind of drilling fluid widely used in the oil and gas industry. Due to the cost of the oil based mud, and the potential thread if oil based mud is dumped, many countries put forward regulations for the recovery of the fluid in oil based mud. It is necessary to recover the fluid in the oil-based drilling fluid to save drilling cost, and to protect environment.

In oil and gas drilling process major portion of the fluid from oil based mud (OBM) is recycled into the drilling fluid system through shale shakers, decanter centrifuges. Yet there is still a big percentage of fluid from OBM being attached to the surface of drilling cuts. Typically, the OOC (oil on cutting) can be up to 15-20%. In other words, about 1/5 of the expensive drilling fluid in OBM is wasted.

In order to solve this challenge, GN Solids Control conducted extensive research and development work and successfully released vertical drilling cut dryer to the market.

A typical application of drilling cut dryer is to position the system in a center location, where transportation vehicles send drilling cut to the location and unload the drilling cut into a collect bin. A conveyor will transport the drilling cut to a hopper, which is mounted on top of the cutting dryer. The cutting comes into the cutting dryer, and the centrifugal force generated by the rotation of rotating basket can be a few hundreds time of G force and thus force the fluid, along with smaller particles, to go through the screen basket and is collected through channel system and flow to a collector, while the solids accumulated on the screen basket is pushed down by tungsten carbide enforced cutting knife and discharged at the bottom of cutting dryer.

Collected fluid has certain concentration of solids under 0.25mm, which needs to be removed by next equipment, decanter centrifuge. GN Solids Control manufactures a series of decanter centrifuge up to 30 inch bowl.

After being processed by decanter centrifuge, the solids in the collected fluids is minimized and is ready to be used for drilling operation again.

A major advantage of vertical cutting dryer is its ability to generate profit, in addition to environment protection, because the fluid is expensive. The base fluid is diesel, which is already costly. The addition of different chemicals, to improve flow dynamic, to increase holding capability of drilling fluid, to protect reservoir formations, to help to dissipate heat generated by the drilling process, and to improve lubrication capability of drill bit, tremendously increased the cost of oil based drilling fluid.

One of GN vertical drilling cut dryer was used by Great Wall Drill. According to the operation manager of the drilling rig, they can save up to USD 3,000 for each cubic meter of fluid recovered. Usually the processing capability of such equipment can process 10 m³/h of drilling cut, and recover 1m³ of drilling fluid. In another word, a vertical drilling cut dryer can recover 8 m³ of drilling fluid an hour, which can save the drilling rig at least $15,000 per each 8 hour shift.

If we put it the other way, the cost of a GN vertical cutting dryer can be recovered in a few months and for the rest of the time, profit generated would be unbelievable.

Offshore Technology Conference has been the top exhibition for oil and gas technologies. It has been held for 50 years. With the 50^th anniversary of OTC, petroleum industry welcomes an important event.

With its continued effort, GN Solids Control put forwarded new and updated products including. At the exhibition, GN Solids presented the following products:

• shale shakers
• decanter centrifuges
• vacuum pumps
• centrifugal pumps

GN Solids Control also bring a series of effectively profitable products to the exhibition, including:

• oil sludge treatment systems
• automatic tank cleaning systems
• vertical cutting dryers
• shale shaker screens, for GN shale shakers and as replacement screens for shale shakers of other brands.

Years of painstaking effort in research and development has been improving the quality, performance, variety and profitability of equipment & systems by GN Solids Control. Some of the products by GN Solids Control with good profitability are:

• Oil sludge treatment system

Long time oil field development activities left many seriously polluted areas in a good number of countries. Nothing can grow on such land and will eventually lead to ecological disaster. This is especially true in the un-developed countries where legislation is weak, so is law enforcement.

However, with ever growth awareness of environment protection, more and more attention is given to the remediation of such pollutions. Oil sludge treatment system from GN Solids Control provides an effective solution to solve this difficult situation.

Such systems take oil sludge, send it to pre-mixer, then convey it to shale shaker by GN. Discharged solids will be delivered to final disposal process. Recovered fluid will be pumped to another mixer for combine with chemicals so that the fluid can be treated with decanter centrifuge. Separated solids will be sent to final disposal process again, which the recovered fluid will be taken over to a 3 phase disc separator, where it will be separated into oil, water and solids.

This process can complete remediate seriously polluted land and can make it arable, for us, and for future generations.

One important thing is that, GN Solids Control can provide all the equipment required by such system and therefore can provide a cost effective and reliable oil sludge system for customers.

• Automatic tank cleaning system

There are countless mud tanks and all kind of other tanks being used worldwide. Cleaning such tank is a major challenge to all the owners of such tanks.

These kind of tanks are used to be cleaned manually, which is pretty tedious and impose a serious risk to the cleaning people because usually the inside of the tanks is refined space and has limited accessibility, there might be toxic gas inside the tanks as well, which can endanger the life of people. In addition, the floor of such tanks is usually pretty slippery, dim, making the cleaning work very dangerous and time consuming.

Automatic tank cleaning system by GN Solids Control effectively solves this problem.

In such system, there is a buffer tank which supply chemical solutions to the cleaning head through a water booster. The cleaning head is inside the tank to be cleaned, and rotates at preset scanning pattern, making the chemical spray to cover all the surface of the tank. Flushed down dirt will be sucked up by a hose connected to a suction pump, which transfer the slurry from the tank to a inclined plate clarifier, where solids is separated from chemical solutions and pumped out through a membrane pump to skip, while the clean chemical solution will overflow to buffer tank, to provide washing material to the cleaning head inside mud tank.

This system is efficient, it can clean one tank in one hour including time to deploy the system. if no relocation is necessary, it can clean on tank in half an hour. It requires at most 2 operators and therefore one man-hour to clean a tank.

If such tank is cleaned by people, it takes 24 to 36 man-hour. In other word, it is 24 to 36 time more efficient than manual cleaning.

Let us do a calculation.

Regular wage for field worker is $50. 36 man-hour is $1,800. With GN automatic tank cleaning system, labor cost is $50, plus electricity, may be another $50.

GN Automatic tank cleaning system provide a very cost effective solution to the labor and cost intensive tank cleaning job.

You can find more information including videos for the field application of the above systems at this link.

Separation of solids from liquid is routinely encountered in industry. There is numerous needs for such differentiation, from iron and steel complex, oil and gas exploration and production, to manufacturing of cooking oil, separation of solids from liquid is indispensable.

Traditionally such separation is done by static setting – mixture of liquid and solids are sent to a container, or a specially designed tank with mechanism inside the tank with the intention to speed up the setting process.

The advantage of such static setting is low cost, as the tank and the associated transferring equipment is all what is needed.

The disadvantage is its low efficiency, as the deposition process is described by Stock’s law. The smaller the difference between the specific gravity of the two phases, the longer time it takes. Sometimes it takes so long that such process makes no sense.

In order to solve this problem, many efforts have been made. The decanter centrifuge by GN Solids Control is a very efficient solution.

Working under the principle of centrifugal force, the decanter centrifuge by GN Solids Control rotates the material inside the spinning bowl at the speed of up to 4500RPM. Generated G force can be up to 3000G. In other word it is 3000 times more efficient than static setting process, if G force is used as the comparison criteria.

Under such separation force, solids is quickly thrown to the surface of the bowl and liquid is floated on top of the set solids. A specially designed decanter inside the rotating bowl, a specially shaped screw conveyor, will send set solids to one side of the bowl and discharge solids through Tungsten Carbide enforced opening. Separated liquid will be discharged from the other end of bowl called weir whose height is adjustable.

A unique features of GN decanter is how the bowl is built. It is centrifugally casted with 2304 stainless steel, which results in pretty evenly distributed density throughout the bowl. This is crucial to the normal operation of the decanter centrifuge because of the very high G force. For instance, 1 gram of out of balance weight can be as big as 3000 gram at the highest rotation speed. Centrifugal casting greatly reduced the potential of out of balance, though it is much more expensive to cast the bowl.

Last week there was a news. To many people there are so many big news that this business cooperation is really a routine, not deserving serious attention.

However this news does symbolize something, automation comes deeper into oil and gas industry.

Last week, Schlumberger, the biggest service company in the world, and Rockwell, a giant in automation technology, came into an agreement to make a joint venture, sensia, to combine advantages of both company and bring revolutionary solutions to the oil and gas industry.

This is the trend. The now joint venture want to release the huge potential of automation in oil and gas industry.

Automation has been widely used in many other industry sectors, such as iron and steel industry, for the control of complex machinery. Many advance technologies such as DCS and SCADA are a backbone of many highly complex process control. One good example is the control of steel pipe straighterner, which make steel pipe straight, round, with less hook end. This is a very advance control technique, which uses wavelet theory to control the accuracy of straightener wheels. This is the accuracy of half millimeter with tens of pressing force on straightener with response speed of micro seconds as the steel pipe is going through the machine at 1m/s speed.

In the oil and gas industry automation technology has been primarily focused on automated operation of remote oil and gas fields, monitoring long distance pipelines , and data collection. This is just the basic application of automation technology, they have no comparison with automation technologies used in other industry sectors such as iron and steel industry.

In solids control technology, there is not much application of automation. However GN Solids Control has been making effort to use automation technology in its products, such as decanter centrifuges. Now GN Solids Control is controlling is decanter centrifuges and monitor their operation parameters with HMI. GN Solids Control is also working on more advanced control technology, such as interlock logics to protect the centrifuges, smart control of differential speed for optimized separation of fed solutions, etc.

Application of automation in solids control equipment has tremendous potential to enhance equipment performance, explore new territories unthinkable ever before, and make great revolution come true.

One big potential of the marriage of automation with solids control equipment is smart shaker screen.

Shaker screens being used in solids control are all “passive” screens because they never play an active role in solids control. They do not know, and there is no way for them to know the condition of incoming fluids, its solids contents, and allowed operation parameters. They simply rock, and rock.

With smart shake screen, this situation will be changed completely one day.

Smart screen execute command from controller, which collect all the information throughout the drilling process, to determine the optimum operating parameters of smart shaker screens.

Smart screen is a power shaker screen.

Traditional shaker screens are mounted on shaker basket with two vibrators linked to the basket. The vibrators “rock” the basket to generate vibration,

Biggest disadvantage of such structure is its g-force. Usually G force generated is about 6-7, with very high quality and high strength basket being able to generate 8-8.5G force. There is not much room for G force to increase in such structure to increase, limited by the strength of steel frame.

However the G force of smart screen can generate unbelievable G force, up to 50G. This is 6 times the G force of best shale shaker.

And the G force is applied on the screen, not on the basket. There is no need for super-strong  steel for the basket.

The secret is the structure of the smart screen.

Underneath the smart screen there is an array of excitors, arranged in a pre-determined position. Each excitor will rock at electrical signal. There are tens of such excitors under the smart screen. With changing timing and strength of electrical signal, the intensity and frequency can be adjusted, to generate right G force for the coming sludge. For instance, G force will be gentle if solids concentration is low, or majority of solids in the sludge are fine particle. If solids concentration is high, or big particle are the majority of solids phase, G force needs to be bigger.

Obviously, two conditions are needed. One is the control of excitors. With complex algorithm, different G force and be generated, or even different G force are generated for different parts of the smart screen. The other is the sensing of particle break-down of incoming sludge. Without automation technology, all these stories will remain stories.

Smart screens sound attractive, yet it is very difficult to make them come true. You have to have a mathematical model, on which you get theoretical solutions to have resonance, and to what magnitude this resonance can be, and what parameters are to be adjusted to tune the intensity of G force.

After all these, a simulation model needs to be established to “run”, to verify the viability of the model, any deficiencies need to be addressed and corrected.

Then it comes to the prototype.

First you have to make the excitors identical. This is not supposed to be a manufacturing challenge as technology today make mass production of such excitors with high consistency possible.

Then the fabrication technology to make mounting the excitors reliably, and wiring them properly, for the very tough operation conditions they are going to face.

The next challenge is the bias effect of many factors resulting from manufacturing and fabrication process. Some of them many have big impact on the resonance of the excitors.

Smart screen appears to be a very promising products, it needs to go through a long way before it become mature.