Abstract: In some examples, coke, tar, or a mixture thereof can be removed from a furnace effluent. The furnace effluent can include coke, tar, or the mixture thereof and can be contacted with a first quench liquid to produce a quenched mixture, wherein the first quench liquid can include a first steam cracker naphtha, a first steam cracker gas oil, a first steam cracker quench oil, or a mixture thereof. The quenched mixture can be introduced into a first inlet of a centrifugal separator drum. A vapor product and a centrifugal separator drum bottoms can be separated from the quenched mixture, wherein the centrifugal separator drum bottoms can include at least a portion of the coke, tar, or the mixture thereof. The centrifugal separator drum bottoms can be recovered from a first outlet of the centrifugal separator drum.

Abstract: Chromium particulate emissions in flue gas can be reduced or minimized by incorporating a thin layer bed of a catalyst within the flue gas flow path of a furnace, boiler, or other furnace environment that includes Cr-containing surfaces. The thin layer bed of catalyst can correspond to, for example, a honeycomb monolith with catalyst supported on the monolith surface, so as to provide a high contact area while forcing all of the flue gas to pass through the catalyst bed. The honeycomb monolith structure and the depth of the bed can be selected to provide a reduced or minimized pressure drop across the catalyst bed, such as a pressure drop of 0.25 kPa (1.0 inches of water) or less. Exposing the Cr-containing flue gas to the thin layer catalyst bed can result in a treated flue gas with a lower content of Cr.

Abstract: In some examples, coke, tar, or a mixture thereof can be removed from a furnace effluent. The furnace effluent can include coke, tar, or the mixture thereof and can be contacted with a first quench liquid to produce a quenched mixture, wherein the first quench liquid can include a first steam cracker naphtha, a first steam cracker gas oil, a first steam cracker quench oil, or a mixture thereof. The quenched mixture can be introduced into a first inlet of a centrifugal separator drum. A vapor product and a centrifugal separator drum bottoms can be separated from the quenched mixture, wherein the centrifugal separator drum bottoms can include at least a portion of the coke, tar, or the mixture thereof. The centrifugal separator drum bottoms can be recovered from a first outlet of the centrifugal separator drum.

Abstract: Chromium particulate emissions in flue gas can be reduced or minimized by incorporating a thin layer bed of a catalyst within the flue gas flow path of a furnace, boiler, or other furnace environment that includes Cr-containing surfaces. The thin layer bed of catalyst can correspond to, for example, a honeycomb monolith with catalyst supported on the monolith surface, so as to provide a high contact area while forcing all of the flue gas to pass through the catalyst bed. The honeycomb monolith structure and the depth of the bed can be selected to provide a reduced or minimized pressure drop across the catalyst bed, such as a pressure drop of 0.25 kPa (1.0 inches of water) or less. Exposing the Cr-containing flue gas to the thin layer catalyst bed can result in a treated flue gas with a lower content of Cr.