Method for purifying crude tall oil soap from black liquor, wherein a washing liquid is used, which washing liquid is either pH-regulated residual liquid from a tall oil producing processing step (180) or a pH-regulated aqueous solution of ash, wherein black liquor-containing crude tall oil soap is mixed with said washing liquid, and wherein the crude tall oil soap is then separated out from the resulting mixture. The method comprises the steps 1. performing a first coarse separation (120,130) of crude tall oil soap from said black liquor, so that a first crude tall oil soap fraction is formed; 2. mixing (140) the first crude tall oil soap fraction with washing liquid, so that a first diluted fraction is formed; and 3. performing a separation (150) of the first diluted fraction using a first centrifugal separator of purificator type, so that a second crude tall oil soap fraction is achieved. The second crude tall oil soap fraction comprises smaller contents of black liquor than the first crude tall oil soap fraction. The invention also relates to a system.

An exchangeable separation insert for a centrifugal separator includes a rotor casing enclosing a separation space in which a stack of separation discs is arranged, and first and second stationary portions. A feed inlet supplies a fluid mixture to the separation space. The insert includes a light phase outlet and a heavy phase outlet. The feed inlet is arranged at a first axial end of the rotor casing. One of the light phase outlet and heavy phase outlet is arranged at a second axial end. A first rotatable seal seals and connects the feed inlet and a second rotatable seal seals and connects one of the light phase outlet and heavy phase outlet.

An exchangeable separation insert for a centrifugal separator includes a rotor casing enclosing a separation space in which a stack of separation discs is arranged, and first and second stationary portions. A feed inlet supplies a fluid mixture to the separation space. The insert includes a light phase outlet and a heavy phase outlet. The feed inlet is arranged at a first axial end of the rotor casing. One of the light phase outlet and heavy phase outlet is arranged at a second axial end. A first rotatable seal seals and connects the feed inlet and a second rotatable seal seals and connects one of the light phase outlet and heavy phase outlet.

An oil separator includes a cylindrical housing that accommodates a rotor and is provided with a gas discharge portion (first exhaust portion), the oil separator being configured to introduce target gas from a rotation center side of the rotor to condense oil mist and emit condensed oil from an outer peripheral edge of the rotor and further being configured to discharge from the housing through the gas discharge portion the blow-by gas (target gas) after having the oil mist separated. The oil separator includes a dome portion (sectioning member) that covers from an outside of the housing the gas discharge portion and sections a closed space around the gas discharge portion and an outlet pipe (second exhaust portion) that is provided to the dome portion and that discharges the blow-by gas from the closed space that is sectioned by the dome portion.

A method of reducing solids accumulation on a disc stack having at least one separator disc used in a centrifuge is provided, comprising: providing at least one surface of the at least one separator disc, said surface having a number of crevices therein; and coating at least a portion of the at least one surface with a coating comprising at least one fluoropolymer to fill the crevices in that portion so that the solids are prevented from settling therein.

A method of reducing solids accumulation on a disc stack having at least one separator disc used in a centrifuge is provided, comprising: providing at least one surface of the at least one separator disc, said surface having a number of crevices therein; and coating at least a portion of the at least one surface with a coating comprising at least one fluoropolymer to fill the crevices in that portion so that the solids are prevented from settling therein.

The invention is characterised in the steps of a) performing a first separation of the mixture in a first centrifugal separator, resulting in a first heavy fraction comprised of the heavy phase with only small amounts of impurities in the form of the light phase and a first light fraction comprising of the light phase with impurities in form of the heavy phase; and b) performing a second separation of the first light fraction in a second hermetic centrifugal separator of purificator type, resulting in a second heavy fraction comprised of the heavy phase with impurities in the form of the light phase and a second light fraction comprised of the light phase with only small amounts of impurities in the form of the heavy phase. The invention also relates to a device.

The invention is characterised in the steps of a) performing a first separation of the mixture in a first centrifugal separator, resulting in a first heavy fraction comprised of the heavy phase with only small amounts of impurities in the form of the light phase and a first light fraction comprising of the light phase with impurities in form of the heavy phase; and b) performing a second separation of the first light fraction in a second hermetic centrifugal separator of purificator type, resulting in a second heavy fraction comprised of the heavy phase with impurities in the form of the light phase and a second light fraction comprised of the light phase with only small amounts of impurities in the form of the heavy phase. The invention also relates to a device.

A centrifugal separator for separating a fluid mixture into components includes a rotor which forms within itself a separation space delimited by a rotor wall, and includes a set of separation plates defining separation passages there between. An inlet is arranged for supply of a fluid mixture to be separated and a first outlet is arranged for a separated lighter first component of the fluid mixture. A sludge space is being defined as an annular portion of the separation space radially outside the separation plates. A second outlet is arranged for discharge of a separated denser second component of the fluid mixture extending from the radially outer portion of the sludge space. A plurality of sludge space plates, which sludge space plates are separate components from the separation plates, is arranged in the sludge space, extending outwardly and in an annular direction with respect to the rotational axis, while forming a gap between the sludge space plates and the rotor wall.

A centrifugal separator for separating a fluid mixture into components includes a rotor which forms within itself a separation space delimited by a rotor wall, and includes a set of separation plates defining separation passages there between. An inlet is arranged for supply of a fluid mixture to be separated and a first outlet is arranged for a separated lighter first component of the fluid mixture. A sludge space is being defined as an annular portion of the separation space radially outside the separation plates. A second outlet is arranged for discharge of a separated denser second component of the fluid mixture extending from the radially outer portion of the sludge space. A plurality of sludge space plates, which sludge space plates are separate components from the separation plates, is arranged in the sludge space, extending outwardly and in an annular direction with respect to the rotational axis, while forming a gap between the sludge space plates and the rotor wall.