Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D19/00—Degasification of liquids
  • B01D19/0042—Degasification of liquids modifying the liquid flow
  • B01D19/0052—Degasification of liquids modifying the liquid flow in rotating vessels, vessels containing movable parts or in which centrifugal movement is caused
  • B01D19/0057—Degasification of liquids modifying the liquid flow in rotating vessels, vessels containing movable parts or in which centrifugal movement is caused the centrifugal movement being caused by a vortex, e.g. using a cyclone, or by a tangential inlet

Definitions

• the invention relates to a method according to claim 1 for removing gas, particularly inert gas bubbles, from process solutions. Moreover, the invention also relates to an arrangement according to claim 15 for removing gas from a solution.
• the bubbles cause aerosol emissions, such as acid and metal emissions to the environment, when being released from the liquid surface of the reactor. Emissions cause health hazards when a possibly toxic gas is emitted from process conditions to the environment, and problems related to corrosion may also occur. It is well known that the removal of gas bubbles from solutions is difficult, and various different arrangements have been developed to solve the problem.
• the degassing equipment includes a cylindrical container, into which liquid is fed tangentially, as it is set in a rotary, downwardly oriented motion.
• the released gas bubbles are removed in countercurrent to the flow from the top part of the container, which is the most essential drawback of said invention.
• the object of the invention is to solve problems related to gas removal.
• the invention relates to eliminating the hazardous effects caused by gas bubbles when processing liquids containing solid substances.
• the preferred embodiments of the invention are set forth in the dependent claims.
• the object of the invention is realized by means of a method according to the independent claim 1 for removing gas, particularly inert gas bubbles, from process solutions, wherein a container containing process solution is provided with means both for feeding gas and solution into a container and for removing gas and solution from the container, said container comprising a separate gas removal tank set therein, into which tank the solution is fed tangentially at the lower part of the gas removal tank, and in which gas removal tank the solution is conducted in a helical, upwardly oriented motion, while the gas bubbles are removed from the top part of the gas removal tank.
• solution is removed at the lower part of the tank.
• the gas removal tank is installed concentrically in the surrounding container.
• the solution is removed from the gas removal tank into the surrounding container.
• the solution is fed to the gas removal tank in an essentially horizontal direction with respect to the lengthwise axis of the gas removal tank. Now the helical flow of the solution inside the gas removal tank is conducted in a desired motion.
• the solution is conducted into the gas removal tank through a feed pipe, the maximum width of the transversal surface of said feed pipe being no more than a fifth of the gas removal tank diameter, at least at the spot where it is connected to the gas removal tank.
• solution is fed to the gas removal tank advantageously at the rate 1 -6 m/s, so that an advantageous helical flow is achieved.
• the diameter and height of the gas removal tank are chosen so that the delay time of the solution containing gas bubbles in the gas removal tank is advantageously at least 10 seconds. The faster the achieved helical flow and the longer the achieved delay time of the solution in the gas removal tank, the more effective is the merging together of gas bubbles.
• the solution is conducted to proceed into an intermediate space left in between the gas removal tank and the container.
• gas removal is made more effective by adjusting the solution flow rate in the intermediate space.
• the maximum flow rate of the solution in the intermediate space is no more than 8 cm/s, in which case there is achieved a good separation of the gas bubbles from the solution.
• the gas removal tank is placed in the container prior to concentrating the solution. According to another embodiment of the invention, the gas removal tank is placed in the container prior to precipitating the solution.
• solids contained in the solution are removed through the lower part of the gas removal tank.
• solids carried along with the solution are removed through the lower part of the container.
• the object of the invention is achieved by using an arrangement according to the invention for removing gas, particularly inert gas, from process solutions, said arrangement comprising, in connection with a container containing process solution, means for feeding both gas and solution to the container and for removing both gas and solution from the container, in which case the container includes a separate gas removal tank, at the lower part of which there is tangentially arranged a solution feed pipe, and in which gas removal tank the solution is conducted in a helical, upwardly oriented motion, the top part of said gas removal tank being provided with means for removing gas.
• the lower part of the container is provided with means for removing solution.
• the gas removal tank is installed concentrically in the surrounding container.
• the lower part of the gas removal tank is at least partially conical and open for removing solids contained in the solution. Consequently, the solids contained in the solution are advantageously removed.
• the means for removing solids from the container are placed as near as possible to the outlet aperture of the gas removal tank.
• the maximum width of the transversal surface of the feed pipe is no more than a fifth of the diameter of the gas removal tank, at least at the spot where it is connected to the gas removal tank.
• the arrangement according to the invention provides for a fast and controlled removal of gas bubbles from the solution.
• bubble clusters are advantageously removed through the top part of the gas removal tank.
• the diameter of the container surrounding the gas removal tank can be chosen to be suitable, depending on the desired diameter of the gas bubbles to be removed.
• An embodiment according to the invention can be included in an existing process, when gas removal problems occur therein. According to the invention, an effective separation of gas bubbles can be affected by adjusting the flow rate of the solution and by designing the measures of the gas removal tank with respect to the existing process requirements.
• Figure 1 a is an illustration in principle of an arrangement according to the invention
• Figure 1 b is an illustration in principle of an arrangement according to the invention
• FIG. 2 illustrates an example according to an embodiment of the invention
• FIG. 3 illustrates an example according to an embodiment of the invention. Detailed description of the invention
• FIG. 1 a and 1 b An arrangement according to the invention for removing gas is illustrated in more detail in Figures 1 a and 1 b, of which 1 b shows the target of Figure 1 a as viewed from the direction A.
• Solution is fed into a container 1 , provided with a separate cylindrical gas removal tank 2, which is installed concentrically with respect to the container and is conical at the lower part 3.
• Solution is fed into the gas removal tank tangentially through the lower part 3, in which gas removal tank 2 the solution 4 is set in a helical, upwardly oriented motion owing to the effect of the centrifugal force.
• the feed flow is conducted from the feed pipe 5 to the gas removal tank 2, so that at the feeding spot, it is perpendicular to the lengthwise axis 6 of the gas removal tank.
• the flow rate of the solution is adjusted to be suitable in the intermediate space 10. Consequently, by means of an arrangement according to the invention, gas removal from a solution can be made more effective by adjusting the flow rate in the intermediate space 10.
• the maximum flow rate in the intermediate space is no more than 8 cm/s, preferably no more than 5 cm/s.
• the lower part 3 of the gas removal tank 2 is conical, in order to carry out the removal of solution and solids through the outlet aperture 13 of the gas removal tank 2 further to the lower part 1 1 of the container 1 .
• the width B of the transversal surface of the feed pipe 5 is proportioned to the length of the diameter C of the gas removal tank 2, so that it is advantageously no more than a fifth of the tank diameter at the point where the feed pipe is connected to the tank.
• a gas removal arrangement according to the example comprises a gas removal tank, which in this example is described as a cyclone, as well as a tank surrounding said cyclone. Water was treated in a gas removal arrangement according to the example, in which case air was fed in the feed pipe of the cyclone.
• the cyclone is set concentrically in the tank, so that solution can be fed tangentially through the lower part of the cyclone.
• the solution is set in a helical, upwardly oriented motion, so that bubbles are removed at the top part of the cyclone, while part of them is carried along with the flow into the intermediate space left between the tank and the cyclone.
• the diameter of the cyclone used in the arrangement according to the example was 300 mm and the height 700 mm; these sizes fluctuate as a function of the feed rate and the turbulent speed. In that case the solution was fed into the cyclone through a feed pipe with a diameter of 40 mm.
• Three different flow rates were used in the tests: 5.1 m 3 /h, 7.4 m 3 /h, and 10.6 m 3 /h.
• the solution feed rates into the cyclone corresponding to said flow rates were 1 .1 m/s, 1 .6 m/s, and 2.3 m/s, and the flow rates in the intermediate space left in between the cyclone and the tank were 2.9 cm/s, 4.2 cm/s and 6.0 cm/s.
• the functional capacity of the invention was estimated by measuring the sizes of the gas bubbles in the intermediate space left in between the cyclone and the tank, at the depth of 630 mm from the free fluid level. The measurement volume is background illuminated by an immersed light, and the pictures were recorded with a digital camera. The contours of the gas bubbles, and therethrough the size of the gas bubbles, could be defined through the gradient of the image intensity.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Degasification And Air Bubble Elimination (AREA)
• Treating Waste Gases (AREA)
• Separation Of Particles Using Liquids (AREA)
• Gas Separation By Absorption (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=41727580

Family Applications (1)

Country Status (10)

Families Citing this family (1)

Family Cites Families (11)

• 2010
  • 2010-02-02 FI FI20100032A patent/FI123403B/fi not_active IP Right Cessation
• 2011
  • 2011-01-31 BR BR112012019081A patent/BR112012019081A2/pt not_active IP Right Cessation
  • 2011-01-31 CN CN2011800080547A patent/CN102740943A/zh active Pending
  • 2011-01-31 EP EP11739444.5A patent/EP2531270A4/de not_active Withdrawn
  • 2011-01-31 PE PE2012001070A patent/PE20130350A1/es not_active Application Discontinuation
  • 2011-01-31 CA CA2786684A patent/CA2786684A1/en not_active Abandoned
  • 2011-01-31 AU AU2011212316A patent/AU2011212316A1/en not_active Abandoned
  • 2011-01-31 WO PCT/FI2011/050077 patent/WO2011095685A1/en not_active Ceased
  • 2011-01-31 EA EA201290648A patent/EA201290648A1/ru unknown
• 2012
  • 2012-07-31 CL CL2012002120A patent/CL2012002120A1/es unknown

Also Published As

Similar Documents

Legal Events