APPARATUSES AND METHODS FOR REMOVING DEPOSITS IN THERMAL CONVERSION PROCESSES

Embodiments of apparatuses and methods for removing deposits in thermal conversion processes are provided herein. In one example, a method comprises advancing a hot vapor through a hot vapor inlet tubular section to a low temperature zone inlet nozzle of a longitudinal tubular section. The hot vapor inlet tubular section has a first inner diameter and the longitudinal tubular section has a second inner diameter that is greater than the first inner diameter. A ram head with a net open cross-sectional flow area is moved between a retracted position and an extended position to remove the deposits in the low temperature zone inlet nozzle.

DETAILED DESCRIPTION

Various embodiments contemplated herein relate to apparatuses and methods for removing deposits in a thermal conversion process such as in a pyrolysis process, e.g., a rapid thermal process (RTP). The exemplary embodiments taught herein provide a branched pipeline that provides fluid communication between a high temperature zone (e.g., reactor cyclone that is fluidly coupled to a RTP reactor) and a low temperature zone (e.g., quenching tower). The branched pipeline includes a longitudinal tubular section that extends distally to define a low temperature zone inlet nozzle. The low temperature zone inlet nozzle is fluidly coupled to the low temperatures zone. A hot vapor inlet tubular section extends from the longitudinal tubular section proximal to the low temperature zone inlet nozzle. The hot vapor tubular section is fluidly coupled to the high temperature zone to receive hot vapor (e.g., RTP gaseous products including a condensable high quality pyrolysis gas at a temperature of about 500° C. or greater).

In an exemplary embodiment, the hot vapor inlet tubular section has a first inner diameter that defines a hot vapor channel that is formed through the hot vapor inlet tubular section. The longitudinal tubular section has a second inner diameter that is greater than the first inner diameter. The second inner diameter defines a longitudinal channel that is open to the hot vapor channel and that extends through the low temperature zone inlet nozzle. A reamer for removing deposits includes a ram head. The ram head has a net open cross-sectional flow area. The ram head is operably disposed in the longitudinal channel to move between a retracted position and an extended position.

In an exemplary embodiment, the hot vapor from the high temperature zone is advanced through a hot vapor inlet tubular section to the low temperature zone inlet nozzle for introduction to the low temperature zone to quench the hot vapor, for example, to a temperature of about 100° C. or less. Over time, coke-like deposits form along the inner surfaces of the longitudinal tubular section adjacent to the low temperature zone including along the inner surfaces of the low temperature zone inlet nozzle. The ram head is moved from a retracted position to an extended position to remove these deposits. Because the ram head has the net open cross-sectional flow area, the hot vapor is able to pass through the ram head during removal of the deposits to reduce or minimize any incremental back pressure that might otherwise cause a substantial hydraulic bounce and/or disruption to the thermal conversion process. Additionally, in an exemplary embodiment, because the longitudinal channel has a greater inner diameter than the hot vapor channel, the ram head can be sized relatively large compared to the hot vapor channel such that the net open cross-sectional flow area is about the same as or greater than the cross-sectional flow area of the hot vapor to further reduce or prevent any incremental back pressure that can cause a substantial hydraulic bounce and/or disruption of the thermal conversion process.

Referring toFIG. 1, a portion of a thermal conversion arrangement10including an apparatus12for removing deposits in the thermal conversion arrangement10in accordance with an exemplary embodiment is provided. As illustrated, the thermal conversion arrangement10includes a high temperature zone14that includes a reactor cyclone18, a low temperature zone20that includes a primary quench tower22, and the apparatus12that is fluidly coupled to both the high temperature zone14via a pipeline24and to the low temperature zone20. As illustrated and will be discussed in further detail below, the apparatus12includes a branched pipeline25and a reamer26.

The reactor cyclone18separates a hot vapor (indicated by dashed arrows27) from heated inorganic solid particles (e.g., sand) that is used to thermally convert a carbonaceous material (e.g., biomass) into the hot vapor27in the RTP reactor. (not shown) which is directly attached to the reactor cyclone In an exemplary embodiment, the hot vapor27has a temperature of about 500° C. or greater, such as from about 500 to about 650° C.

The hot vapor27is advanced through the pipelines24and25for introduction to the primary quench tower22. The primary quench tower22quickly quenches the majority of the condensable pyoil in the incoming hot vapor27into a liquid pyoil product, which creates a hot-cold interface zone. In an exemplary embodiment, the hot vapor27is quenched in the primary quench tower22to a temperature of about 100° C. or less, such as from about 50 to about 100° C. to form the liquid product. As will be discussed in further detail below, the reamer26removes coke-like deposits and other product deposits that form along portions of the branched pipeline25due to the hot-cold interface zone, thereby preventing unwanted increases in system back pressure.

Referring toFIG. 2, a sectional side view of the apparatus12in accordance with an exemplary embodiment is provided. The branched pipeline25of the apparatus12includes a longitudinal tubular section28that extends from a proximal section30to a distal section32. The distal section32of the longitudinal tubular section28forms a low temperature zone inlet nozzle34that is fluidly coupled to the low temperature zone20. A hot vapor inlet tubular section36extends from the longitudinal tubular section28proximal the low temperature zone inlet nozzle34and is fluidly coupled to the pipeline24(seeFIG. 1).

In an exemplary embodiment, the hot vapor inlet tubular section36has an inner diameter (indicated by double headed arrow D1) that defines a hot vapor channel38having a relatively circular cross-sectional flow area. As such, the cross-sectional flow area of the hot vapor channel38corresponds to about π(D1)2/4.

In an exemplary embodiment, the longitudinal tubular section28has an inner diameter (indicated by double headed arrow D2) that defines a longitudinal channel40having a relatively circular cross-sectional flow area. Likewise, the cross-sectional flow area of the longitudinal channel40corresponds to about π(D2)2/4.

The inner diameter D2and the corresponding net cross-sectional flow area of the longitudinal channel40are greater than the inner diameter D1and the corresponding cross-sectional flow area of the hot vapor inlet tubular section36, respectively. In an exemplary embodiment, the inner diameter D2is about 105% or greater of the inner diameter D1, such as from about105to about 150% of the inner diameter D1.

As illustrated, the longitudinal channel40is open to the hot vapor channel38and extends through the low temperature zone inlet nozzle34. This allows the hot vapor27from the high temperature zone14(seeFIG. 1) to pass through the hot vapor channel38, the longitudinal channel40including the low temperature zone inlet nozzle34, to the low temperature zone20. The hot-cold interface zone adjacent to the low temperature zone20extends along the inner surfaces41of the low temperature zone inlet nozzle34and, as such, coke-like deposits and other product deposits can build up along these inner surfaces41.

The reamer26includes a rod42and a ram head44. The ram head44is operably coupled to a distal end section of the rod42and the proximal end section of the rod42is operably coupled to an actuator46.

Referring also toFIG. 4, in an exemplary embodiment, the ram head44has a tubular wall48that is disposed substantially coaxial with the longitudinal tubular section28and that surrounds a ram head channel50. A plurality of spokes52are disposed in the ram head channel50and extend radially outward from the rod42to operably couple the tubular wall48with the rod42. The actuator46is configured to move the rod42together with the ram head44through the longitudinal channel40between a retracted position54and an extended position56.

As illustrated inFIG. 2, a gap (indicated by arrows57) is formed between the tubular wall48and an inner surface of the longitudinal tubular section28. In an exemplary embodiment, the gap57is about 2 mm or greater, such as from about 2 to about 4 mm.

As illustrated inFIGS. 2 and 4, the ram head channel50extends longitudinally through ram head44such that both the distal end58and the proximal end60of the ram head44are open. As such, the ram head44has a net cross-sectional flow area61to allow the hot vapor27to pass through the ram head44while the ram head44is being moved between the retracted and extended positions54and56. In an exemplary embodiment, the net open cross-sectional flow area61of the ram head44is defined as a cross-sectional area of the ram head channel50less a combined cross-sectional area of the rod42and the spokes52. In an exemplary embodiment, the net open cross-sectional flow area61is about 100% or greater, such as from about 100 to about 110%, of the cross-sectional flow area of the hot vapor inlet tubular section36.

Referring toFIGS. 2,3, and5, in an exemplary embodiment, a slot opening62is formed through an intermediate section64of the tubular wall48between a leading continuous edge section66and a trailing continuous edge section68. In an exemplary embodiment, for structure, the leading and trailing continuous edge sections66and68of the ram head44have corresponding minimum longitudinal lengths (indicated by arrows L1and L2) of at least about 5 mm, such as from about 5 to about 25 mm. As illustrated, the leading continuous edge section66has a leading beveled edge69to facilitate removing the deposits.

In an exemplary embodiment, the slot opening62has a slot opening flow area68that is defined by a length (indicated by double headed arrow L3) and a width (indicated by arrows W). In an exemplary embodiment, the slot opening flow area68is greater than the cross-sectional flow area (indicated inFIG. 3by dashed lines70) of the hot vapor channel38. In one example, the slot opening flow area68is about 105% or greater, such as from about 105 to about 150%, of the cross-sectional flow area70of the hot vapor chamber38. In an exemplary embodiment, the length L3and width W of the slot opening flow area68are independently about the same as or greater than the inner diameter D1of the hot vapor inlet tubular section36. In another exemplary embodiment, the slot opening62is positioned along the tubular wall48such that when the ram head44is in an intermediate position72, the slot opening62and the hot vapor channel38are matched and aligned to allow the hot vapor27from the hot vapor inlet tubular section36to pass through the slot opening62into the ram head channel50and the longitudinal channel40substantially unobstructed.

Accordingly, apparatuses and methods for removing deposits in a thermal conversion process have been described. The exemplary embodiments taught herein provide a branched pipeline that provides fluid communication between a high temperature zone and a low temperature zone. The branched pipeline includes a longitudinal tubular section that extends distally to define a low temperature zone inlet nozzle. A hot vapor inlet tubular section extends from the longitudinal tubular section proximal to the low temperature zone inlet nozzle. In an exemplary embodiment, the hot vapor inlet tubular section has a first inner diameter that defines a hot vapor channel that is formed through the hot vapor inlet tubular section. The longitudinal tubular section has a second inner diameter that is greater than the first inner diameter. The second inner diameter defines a longitudinal channel that is open to the hot vapor channel and that extends through the low temperature zone inlet nozzle. A reamer for removing deposits includes a ram head. The ram head has a net open cross-sectional flow area. The ram head is operably disposed in the longitudinal channel to move between a retracted position and an extended position. Because the ram head has the net open cross-sectional flow area, the hot vapor is able to pass through the ram head during removal of the deposits to reduce or minimize any incremental back pressure that might otherwise cause a substantial hydraulic bounce and/or disruption to the thermal conversion process.