CLOSED, GASTIGHT SYSTEM AND METHOD FOR GAINING SELLABLE PETROLEUM COKE PIECES OUT OF SOLIDIFIED PETROLEUM COKE IN A COKE DRUM UNIT

Abstract

A closed, gastight system for gaining sellable petroleum coke pieces out of solidified petroleum coke in a coke drum unit, wherein the system is configured to be connected to a coke drum unit (X) containing solidified petroleum coke and comprises a coke crushing unit (C) for crushing the petroleum coke into sellable petroleum coke pieces, configured to be connected to the coke drum unit (X), particularly by means of a flexible transition piece (A); a closed sluice way (D) leading petroleum coke slurry to a closed slurry basin; a closed slurry basin (E); a dewatering bin unit (G) configured to receive the petroleum coke slurry from the slurry basin (E), to collect the sellable petroleum coke pieces, and to act as a filter leading runoff drain water from a lower area thereof as filtered water and petroleum coke fines out of it; a closed drain water basin (I), separate from the slurry basin (E), configured to receive the filtered water and the petroleum coke fines from the dewatering bin unit (G); a water tank (L) configured to receive the filtered water from the drain water basin (I); a hot quench water draining line (2) configured to receive hot quench water from the coke drum unit (X) and to lead the same to the closed slurry basin (E); and characterised: in that the water tank (L) is configured as single water tank (L) without a separate second tank; and by comprising one or more of the following elements: a first vent collection line (15a) extending from a top portion of the closed slurry basin (E) to the clean water tank (L), particularly a top portion thereof, for collecting excess amounts of gaseous phase from the slurry basin (E) and for feeding the same to the clean water tank (L); a second vent collection line (15b) extending from the dewatering bin unit (G), particularly a top portion thereof, to the clean water tank (L), particularly a top portion thereof, for collecting excess amounts of gaseous phase from the dewatering bin unit (G) and for feeding the same to the clean water tank (L); and a third vent collection line (15c) extending from the closed drain water basin (I), particularly a top portion thereof, to the clean water tank (L), particularly a top portion thereof, for collecting excess amounts of gaseous phase from the closed drain water basin (I) and for feeding the same to the clean water tank (L); and by comprising a fourth vent collection line (15d) extending from the water tank (L), particularly a top portion thereof, to a vent treatment unit, in particular to a vent incineration unit.

Claims

1. A closed, gastight system for gaining sellable petroleum coke pieces out of solidified petroleum coke in a coke drum unit, wherein the closed, gastight system is configured to be connected to a coke drum unit (X) containing solidified petroleum coke and comprises a coke crushing unit (C) for crushing the petroleum coke into sellable petroleum coke pieces, configured to be connected to the coke drum unit (X), particularly by means of a flexible transition piece (A); a closed sluice way (D) leading petroleum coke slurry to a closed slurry basin; a closed slurry basin (E); a dewatering bin unit (G) configured to receive the petroleum coke slurry from the closed slurry basin (E), to collect the sellable petroleum coke pieces, and to act as a filter leading runoff drain water from a lower area thereof as filtered water and petroleum coke fines out of it; a closed drain water basin (I), separate from the slurry basin (E), configured to receive the filtered water and the petroleum coke fines from the dewatering bin unit (G); a water tank (L) configured to receive the filtered water from the closed drain water basin (I); a hot quench water draining line (2) configured to receive hot quench water from the coke drum unit (X) and to lead the same to the closed slurry basin (E); and characterised in that the water tank (L) is configured as a single water tank (L) without a separate second tank; and comprises one or more of the following elements: a first vent collection line (15a) extending from a top portion of the closed slurry basin (E) to the clean water tank (L), particularly a top portion thereof, for collecting excess amounts of gaseous phase from the slurry basin (E) and for feeding the same to the clean water tank (L); a second vent collection line (15b) extending from the dewatering bin unit (G), particularly a top portion thereof, to the clean water tank (L), particularly a top portion thereof, for collecting excess amounts of gaseous phase from the dewatering bin unit (G) and for feeding the same to the clean water tank (L); and a third vent collection line (15c) extending from the closed drain water basin (1), particularly a top portion thereof, to the clean water tank (L), particularly a top portion thereof, for collecting excess amounts of gaseous phase from the closed drain water basin (1) and for feeding the same to the clean water tank (L); and a fourth vent collection line (15d) extending from the water tank (L), particularly a top portion thereof, to a vent treatment unit, in particular to a vent incineration unit.

2. A closed, gastight system according to claim 1, wherein the slurry basin (E) is configured as closed, emission-free slurry basin (E), which does not discharge to the environment; and/or wherein the drain water basin (1) is configured as closed, emission-free drain water basin (1), which does not discharge to the environment.

3. A closed, gastight system according to claim 1, further comprising a cooling water line (3) leading from the water tank (L), including from a intermediate portion thereof, to the hot quench water draining line (2), including to a joining point (JP) in the hot quench water draining line (2) at a position above the closed slurry basin (E), configured to feed cooling water from the water tank (L) to the hot quench water in the hot quench water draining line (2), in order to prevent steam generation within the slurry basin (E).

4. A closed, gastight system according to claim 3, wherein a mixing unit (B), including a static mixer, is provided in the hot quench water draining line (2), including at the position of the joining point (JP) of the cooling water line (3), or at a position downstream of the joining point (JP) of the cooling water line (3), but upstream of the inlet of the closed slurry basin (E).

5. A closed, gastight system according to claim 1, wherein a heat rejection heat exchanger (N) is provided in the cooling water line (3), configured to reduce the temperature of the cooling water flowing through the cooling water line (3), against a secondary heat exchange medium, including environmental air.

6. A closed, gastight system according to claim 1, wherein a transport water pump (M) is provided in the cooling water line (3), including at a position upstream of the heat rejection heat exchanger (N).

7. A closed, gastight system according to claim 1, further comprising a quench water line (1) leading from the single water tank (L) to the coke drum unit (X), for filling the coke drum unit (X) with water, thereby hardening and cooling the solidified petroleum coke; and/or wherein a quench water pump (S) is provided in the quench water line (1).

8. A closed, gastight system (2) according to claim 1, further comprising a control unit, wherein, during operation of the closed, gastight system, the solidified petroleum coke is at a temperature of up to 550 C., and the water in the single water tank (L) and flowing into the cooling water line (3) is at a temperature of 60 to 80 C.; wherein the control unit is configured to supply quench water to the coke drum unit (X) through the quench water line, in which the water stands up to 60 m high, such that the water heats up to a temperature of up to 165 C. within the coke drum unit (X) and has a pressure level of up to 6 bar, without evaporating; wherein the control unit is further configured to operate the transport water pump (M) and the heat rejection heat exchanger (N) such that a cooling water flow mixes with the hot water in the hot quench water draining line (2), such that the temperature of the hot drain water is reduced to a temperature of around 85-95 C. before reaching the slurry basin I; wherein the control unit is further configured to operate the heat rejection heat exchanger (N) in the cooling water line (3), such that the temperature of the cooling water flowing through the cooling water line (3) is cooled against a secondary heat exchange medium, including environmental air, to a temperature of around 50 to 70 C.

9. A closed, gastight system according to claim 1, wherein a drain water discharge line (7) is provided connecting the closed drain water basin (1) to the water tank (L); wherein a drain water pump (P) and a centrifugal separation device, including a hydro cyclone device (Q), for separating slurry particles out of the drain water from the drain water basin (1) is provided in the drain water discharge line (7); and/or wherein a dirty water pit (O), separate from the drain water basin (1) and separate from the slurry basin I, is provided, which is configured to receive the slurry particles separated by the centrifugal separation device (Q); and/or wherein a dirty water supply line/sludge line (11) is provided, leading from the dirty water pit (O) to the dewatering bin unit (G); and/or wherein a dirty water pump (P) is provided at or in the dirty water pit (O), or in the dirty water supply line (11).

10. A closed, gastight system according to claim 9, wherein the single water tank (L) comprises a sedimentation stage configured to separate solid particles at its bottom portion, including at its low point; and/or wherein a solid particle discharge line (10) is provided connecting the single water tank (L), including its bottom portion to the dirty water pit (O); and/or wherein the single water tank (L) is configured a single water tank (L) without a separate second tank.

11. A closed, gastight system according to claim 1, further comprising at least one of the following elements: a slurry line (5) connecting the slurry basin I to the dewatering bin unit (G), including to a top portion thereof, for pumping petroleum coke slurry to the dewatering bin unit (G); and/or wherein a slurry pump (F) is provided in the slurry line (5); and a flushing line (4) branching off from the cooling water line (3) and leading to the sluice way (D), for supporting flushing and pumping of the petroleum coke slurry to the slurry basin I; and/or wherein a valve (V3) is provided in this flushing line (4).

12. A method for gaining sellable petroleum coke pieces out of solidified petroleum coke in a coke drum unit (X), using the closed, gastight system of claim 3, comprising the steps of in a quenching and quench water cooling operation, flooding the coke drum unit (X), by means of a quench water supply line (1) leading from a single water tank (L) to the coke drum unit (X), and draining the hot quench water to a slurry basin I via a hot quench water line (2), thereby hardening and cooling the solidified petroleum coke; wherein a cooling water flow is fed from a water tank (L), including from a bottom portion thereof, through a cooling water line (3) to the hot quench water draining line (2), including to a joining point (JP) in the hot quench water draining line (2) at a position above the slurry basin I, in order to cool the hot water in the hot quench water draining line (2), in order to prevent steam generation within the slurry basin I.

13. A method of claim 12, wherein, during operation of the closed, gastight system, the water in the single water tank (L) and flowing into the cooling water line (3) is at a temperature of around 70 C.; wherein, during beginning of the quenching and quench water cooling operation, the solidified petroleum coke is at a temperature of up to 550 C., and wherein, in the flooding step, quench water is supplied to the coke drum unit (X) through the quench water line (1), which stands up to 60 m high within the coke drum unit, such that the water heats up in the coke drum unit (X) to a temperature of up to 165 C., and has a pressure level of up to 6 bar, without evaporating; wherein, in the draining step, the transport water pump (M) and, including also the heat rejection heat exchanger (N) is/are operated such that the cooling water flow mixes with the hot water in the hot quench water draining line (2), such that the temperature of the hot drain water is reduced to a temperature of around 85-95 C. in the hot quench water draining line (2) before reaching the slurry basin I; and/or wherein in the draining step, the heat rejection heat exchanger (N) in the cooling water line (3) is operated, such that the temperature of the cooling water flowing through the cooling water line (3) is cooled against a secondary heat exchange medium, including environmental air, to a temperature of around 50 to 70 C.

14. A method for gaining sellable petroleum coke pieces out of solidified petroleum coke in a coke drum unit (X), using the closed, gastight system of claim 9, comprising a water treatment operation comprising leading drain water from the closed drain water basin (1) to the water tank (L) through a drain water discharge line (7) connecting the closed drain water basin (1) to the single water tank (L), including to an upper portion thereof, and using a drain water pump (P); separating slurry particles out of the drain water from the drain water basin (1) using a centrifugal separation device, including a hydro cyclone device (Q), in the drain water discharge line (7); receiving the slurry particles separated by the centrifugal separation device (Q) in a dirty water pit (O), separate from the drain water basin (1) and separate from the slurry basin I; leading dirty water from the dirty water pit (O) to the dewatering bin unit (G), through a dirty water supply line (11), using a dirty water pump (P) provided at or in the dirty water pit (O), or in the dirty water supply line (11); separating solid particles at the bottom portion at the low point of the single water tank (L); and draining the solid particles from the bottom portion, including the low point of the single water tank (L), through a solid particle discharge line (10) to the dirty water pit (O), wherein the solid particle discharge line (10) connects the single water tank (L), including its bottom portion to the dirty water pit (O).

15. A method for gaining sellable petroleum coke pieces out of solidified petroleum coke in a coke drum unit (X), using the closed, gastight system of claim 1, comprising a water treatment operation comprising at least one of the first three, and the fourth of the following steps: collecting excess amounts of gaseous phase from the slurry basin I and feeding the same to the clean water tank (L) by means of a first vent collection line (15a) extending from a top portion of the closed slurry basin I to the clean water tank (L), including a top portion thereof; and/or collecting excess amounts of gaseous phase from the dewatering bin unit (G) and feeding the same to the clean water tank (L) by means of a second vent collection line (15b) extending from the dewatering bin unit (G), including a top portion thereof, to the clean water tank (L), including a top portion thereof; and/or collecting excess amounts of gaseous phase from the closed drain water basin (1) and feeding the same to the clean water tank (L) by means of a third vent collection line (15c) extending from the closed drain water basin (1), including a top portion thereof, to the clean water tank (L), including a top portion thereof; and collecting excess amounts of gaseous phase from the clean water tank (L) and feeding the same to a vent treatment unit, including to a vent incineration unit, by means of a fourth vent collection line (15d) extending from the clean water tank (L), including a top portion thereof, to a vent treatment unit, including to a vent incineration unit.

16. A closed, gastight system according to claim 2, further comprising a cooling water line (3) leading from the water tank (L), including from a intermediate portion thereof, to the hot quench water draining line (2), including to a joining point (JP) in the hot quench water draining line (2) at a position above the closed slurry basin (E), configured to feed cooling water from the water tank (L) to the hot quench water in the hot quench water draining line (2), in order to prevent steam generation within the slurry basin (E).

17. A closed, gastight system according to claim 2, wherein a heat rejection heat exchanger (N) is provided in the cooling water line (3), configured to reduce the temperature of the cooling water flowing through the cooling water line (3), against a secondary heat exchange medium, including environmental air.

18. A closed, gastight system according to claim 2, wherein a transport water pump (M) is provided in the cooling water line (3), including at a position upstream of the heat rejection heat exchanger (N).

19. A closed, gastight system according to claim 2, further comprising a quench water line (1) leading from the single water tank (L) to the coke drum unit (X), for filling the coke drum unit (X) with water, thereby hardening and cooling the solidified petroleum coke; and/or wherein a quench water pump (S) is provided in the quench water line (1).

20. A closed, gastight system (2) according to claim 2, further comprising a control unit, wherein, during operation of the closed, gastight system, the solidified petroleum coke is at a temperature of up to 550 C., and the water in the single water tank (L) and flowing into the cooling water line (3) is at a temperature of 60 to 80 C.; wherein the control unit is configured to supply quench water to the coke drum unit (X) through the quench water line, in which the water stands up to 60 m high, such that the water heats up to a temperature of up to 165 C. within the coke drum unit (X) and has a pressure level of up to 6 bar, without evaporating; wherein the control unit is further configured to operate the transport water pump (M) and the heat rejection heat exchanger (N) such that a cooling water flow mixes with the hot water in the hot quench water draining line (2), such that the temperature of the hot drain water is reduced to a temperature of around 85-95 C. before reaching the slurry basin I; wherein the control unit is further configured to operate the heat rejection heat exchanger (N) in the cooling water line (3), such that the temperature of the cooling water flowing through the cooling water line (3) is cooled against a secondary heat exchange medium, including environmental air, to a temperature of around 50 to 70 C.

Description

[0156] This system can also be called environmental coke handling operation, or ECHO.

[0157] The system ECHO comprises a coke crushing unit C installed underneath and connected to the bottom outlet of the coke drum unit X by means of a transition piece A.

[0158] The bottom outlet of the coke crushing unit C is connected by means of a closed sluice way D to a slurry basin E.

[0159] A hot quench water draining line 2 extends from the coke drum unit X to the slurry basin E, and a mixing unit B is arranged within this hot quench water draining line 2, particularly downstream of a joining point JP of a cooling water line 3 which will be explained in further detail below.

[0160] A slurry line 5 extends from the slurry basin E to a dewatering bin unit G, particularly to a top portion thereof, and a slurry pump F is arranged within this slurry line 5.

[0161] The low point of the dewatering bin unit G is connected to a vibration feeder H which in turn leads to a closed coke conveyor and/or to a coke storage unit (not shown).

[0162] A drain water supply line 6 attaches to an intermediate level portion of the dewatering bin unit 6 and leads to a drain water basin I.

[0163] A drain water discharge line 7 extends between the drain water basin I and a hydrocyclone Q, and a drain water pump K is arranged within this drain water discharge line 7.

[0164] A clean water supply line 8 extends from the hydrocyclone Q, particularly from its upper portion to a single water tank L.

[0165] A dirty water supply line 9 extends from the hydrocyclone Q, particularly from its bottom portion to a dirty water pit O.

[0166] A dirty water pump P is provided within the dirty water pit O, and connects to a dirty water supply line/sludge line 11 that extends from the dirty water pit O to the dewatering bin unit G, particularly to its top portion.

[0167] A quench water supply line 1 attaches to the water tank L, particularly to an intermediate level portion thereof and extends to the coke drum unit X. A quench water pump S is arranged within this quench water supply line 1.

[0168] A cutting pump water line 14 attaches to the water tank L, particularly to an intermediate level portion thereof, and it also extends to the coke drum unit X, particularly to a top portion thereof (not shown). A cutting pump R is arranged within this cutting pump water line 14.

[0169] A make up water supply line 13 is shown to attach to the water tank L at an upper-level portion thereof. This make up water supply line 13 is connected to a water supply (not shown) and comprises a valve V4 by means of which the make up water supply line 13 can be opened or closed or by means of which the amount of make up water flow to the water tank L can be adjusted.

[0170] A cooling water line 3 connects to an intermediate level portion of the water tank L and extends to the joining point JP at the hot quench water draining line 2. A transport water pump M and a heat rejection heat exchanger/air cooler N are arranged within this cooling water line 3.

[0171] A solid particle discharge line 10 attaches to the low point of the water tank L and leads to the dirty water pit O.

[0172] A cooling water backflow line 12 attaches to the cooling water line 3 at a position downstream of the air cooler N and connects to the water tank L, particularly to an intermediate level portion thereof. A valve V2 is arranged within this cooling water back flow line 12 by means of which this line can be opened or closed or the amount of the flow through this line can be adapted.

[0173] A valve V1 is arranged within the cooling water line 3, particularly at an end portion thereof, just upstream of the joining point JP. By means of this valve V1, the cooling water line 3 can be opened or closed and/or the amount of the cooling water flow can be adapted to the respective needs.

[0174] A flushing line 4 branches off the cooling water line 3, particularly at an end portion thereof and is connected to the sluiceway D, particularly an upper portion thereof. A valve V3 is arranged within this flushing line 4 which enables opening or closing the flushing line 4 and/or adjusting the amount of flushing water flow through this flushing line 4.

[0175] A first vent collection line 15a connects to a top portion of the closed slurry basin E, and leads to the clean water tank L, particularly a top portion thereof. This first vent collection line 15a is configured to collect excess amounts of gaseous phase from the slurry basin E and to feed the same to the clean water tank L.

[0176] A second vent collection line 15b connects to a top portion of the dewatering bin G and leads to the clean water tank L, particularly a top portion thereof. This second vent collection line 15b is configured to collect excess amounts of gaseous phase from the dewatering bin unit G and to feed the same to the clean water tank L.

[0177] A third vent collection line 15c connects to a top portion of the closed drain water basin I and leads to the clean water tank L, particularly a top portion thereof. This third vent collection line 15c is configured to collect excess amounts of gaseous phase from the drain water basin I and to feed the same to the clean water tank L.

[0178] In the FIGURE, the first, second, and third vent collection lines 15a, 15b and 15c are formed by the first vent collection line 15a leading from the slurry basin E to the clean water tank L and by separate second and third vent collection lines 15b and 15c joining into this first vent collection line 15a, thereby forming a joint collection line 15.

[0179] In an alternative embodiment, which is not shown here, the three vent collection lines 15a, 15b and 15c can be formed as a separate vent collection lines leading from this slurry basin E/from the dewatering bin unit G/from the drain water basin E, respectively, to the clean water tank L.

[0180] A fourth vent collection line 15d connects to the water tank L, particularly a top portion thereof, and leads to a vent treatment unit (not shown), for example a vent incineration unit. This fourth vent collection line 15d is configured to collect excess amounts of gaseous phase from the clean water tank L and to feed the same to a vent treatment unit (not shown), for example a vent incineration unit.

[0181] By these vent collection lines 15a-15d it is reliably avoided that gaseous phase/steam containing coke particles gets into the environment. Rather the gaseous phase/the steam which typically contains coke particles, is collected from this slurry basin E/from the dewatering bin unit G/from the drain water basin E and fed to the clean water tank L. From the clean water tank L, the gaseous phase of the water/the steam which typically contains coke particles which collects therein is not released into the environment via one or more vents, which is the case for other systems, but rather is fed to a vent treatment unit (not shown), for example a vent incineration unit.

[0182] The operation of the coke drum unit X is normally a cyclic operation of typically 18 to 24 hours of coking followed by a stage called decoking.

[0183] During the coking stage, so called petroleum coke is produced and settles as solid agglomerate in the coke drum unit X, while other products of this process leave the coke drum unit X at the top for further treatment. This is continued until the coke drum unit X is filled with solid petroleum coke to a defined level.

[0184] In the next stage, namely the decoking stage, this solid/solidified petroleum coke needs to be removed from the coke drum unit X.

[0185] During the decoking stage, the agglomerated and solidified petroleum coke is cut by means of high-pressure cutting water taken from the water tank L and supplied to the coke drum unit X through the cutting pump water line 14 and by means of the cutting pump R.

[0186] The system ECHO as shown in FIG. 1 is designed to handle the coke as a zero-emission reliable and safe system. The system ECHO is capable to crush petroleum coke, by means of the coke crushing unit C, then route it as slurry, which is to be understood as a mixture of crushed coke particles and water from the coke drum unit X through the transition piece A, through the coke crushing unit C and through the closed sluice way D to the slurry basin E, to the dewatering bin unit G. Finally, sellable coke pieces get from the dewatering bin unit G through the coke discharge to the vibration feeder H and from there to the coke storage area.

[0187] The system ECHO as it is described here provides a highly efficient separation of coke from water and produces clean water to be reused in the decoking process.

[0188] The system ECHO is typically a batch process which is operated in four process stages, namely: [0189] 1. Quench water cooling; [0190] 2. Coke crushing and slurry transport; [0191] 3. Dewatering; and [0192] 4. Dry coke discharge.

1. Quench Water Cooling;

[0193] At first, quench water is supplied from the water tank L through the quench water supply line 1 by the operation of the quench water pump S to the coke drum unit X, which is closed at its bottom, until the quench water stands up to 40 meter high in the coke drum unit. The hot solidified petroleum coke in the coke drum unit has typically a temperature of up to 550 C. before the quenching is started. The water cools down the coke and in turn heats up and partially evaporates. The hydrostatic pressure inside the coke drum (height up to 60 m) can lead to a pressure of up to 6 bar, which can result in water temperatures of up to 165 C. without evaporating.

[0194] Then, the coke drum unit X is drained through the header (not shown) such that this hot quench water flows into the hot water draining line 2. Cooling water is fed from the water tank L by the operation of the transport water pump M to the joining point JP within the hot water draining line 2. For this purpose, the valve V1 is opened.

[0195] The water in the water tank L is typically at a temperature of around 60 to 80 C. By an air cooler N provided in the cooling water line 3, the temperature of the cooling water flow can be reduced to be in the range of around 50 to 70 C.

[0196] The mixing unit B provides for a constant flow downstream thereof and can be controlled such that the temperature of the water flow leaving the mixing unit at its downstream end is below 100 C. at atmosphere level, particularly at a temperature of 85-95 C. or less such that the cooled down quench water arriving in the slurry basin E remains liquid and does not evaporate, thereby reliably preventing steam generation within the slurry basin E.

2. Coke Crushing and Slurry Transport,

[0197] The operational stage of hydraulic coke drilling/cutting starts with drilling a pilot whole into the solidified petroleum coke (drilling/cutting means are not shown). High pressure water that is supplied through the cutting water line 14 by means of the cutting pump R is used for the drilling step and to cut the coke in the coke drum unit X. The cut coke falls down through the transition piece A and is crushed by the coke crushing unit C down to a particle size of maximum 100 mm. Then, the crushed coke/water mixture flows, through the closed sluice way into the slurry basin E. A highly specialised slurry pump F conveys the mixture of coke and water through the slurry line 5 to the dewatering bin G.

[0198] The coke particles in the mixture will be trapped and retained in the coke bed in the dewatering bin unit G, while the drain water drains off from the dewatering bin unit G through the drain water supply line 6 into the drain water basin I. The slurry pump F is configured to be capable of transporting slurry having a coke/water ratio of 1 to 2 without plugging.

[0199] The main function of the dewatering bin G is to separate coke from water by a filtering process.

3. Dewatering

[0200] During the dewatering stage, a coke bed is formed within the dewatering bin unit G, and coke fines in the slurry are retained by the coke bed, while the clean water drains off into the drain water basin I through the drain water supply line 6. In particular, water drains through filter elements in an upper and lower collection ring attached to the dewatering bin unit G. The dewatering bin unit G is typically equipped with filtration screens, which are uniformly placed along its inner wall.

[0201] Once there is enough coke in the dewatering bin unit G to form a filtration bed, the filtrate quality improves, and the drain water flows from the dewatering bin unit G, through the drain water supply line 6 to the drain water basin I, until the end of the dewatering stage.

[0202] The lower part of the dewatering bin unit G can be equipped with a conical screen, which is connected with a lower dewatering ring line which can also be called core dewatering line.

[0203] The hydraulic head generated between the outlet to the drain water supply line 6 of the dewatering bin unit G and the drain water basin I induces a negative pressure in the core dewatering line which supports the water flow through the voids of coarse coke material.

4. Dry Coke Discharge

[0204] Once the coke cutting is completed and the slurry pump F has been stopped, the drain water flow will reduce over time and approach a flow rate of 0 m.sup.3/h. When no more water is draining through the drain water supply line 6 the coke can be considered dry and ready for discharge.

[0205] In the dry coke discharge stage, the coke product will be discharged from the dewatering bin unit G to the coke conveyor system via a load out vibration feeder H to a conveying system and subsequently to storage facilities of sellable petroleum coke (not shown).

Water Treatment

[0206] During all stages, water treatment is conducted continuously as will be explained below.

[0207] The drain water from the dewatering bin unit G, especially during the beginning of the dewatering stage, contains a substantial amount of coke fines that need to be removed by further water treatment before being able to reuse the water.

[0208] The drain water from the dewatering bin unit G including the coke fines is received in the drain water basin I. From there, the drain water pump K pumps it through the hydrocyclone Q, which is a centrifugal separation device, to the water tank L via the clean water supply line 8. In this hydrocyclone Q coke fines and solids from the drain water are separated and are directed through the dirty water supply line 9 to the dirty water pit O.

[0209] From the dirty water pit O, the slush contained therein is pumped by the dirty water pump P and through the slush/dirty water supply line 11 to the dewatering bin unit G, where the coke fines and solids are trapped and retained in the coke filter bed and are effectively removed from the process.

[0210] The water that has been filtered/purified by the hydrocyclone Q is received in the water tank L which serves as the water inventory for the process. In the sedimentation stage of the water tank L, the solid particles that are still comprised in the water are collected at its bottom portion, particularly at its low point. This low point is drained through the solid particle discharge line 10 to the dirty water pit O e.g. in regular intervals.

[0211] The water from the water tank L can be used as high-pressure cutting water (line 14), as quench water (line 1), or as cooling and transport water (cooling line 3).

[0212] For the system ECHO that has been described above with reference to the sole FIGURE, all the above advantageous and embodiments, that have been explained in the general part of the description, apply and they are not repeated here for brevity.

[0213] In other embodiments the coke drum unit X comprises two or more sets of a coke drum X, of a transition piece A, of a coke crushing unit C, of a closed sluiceway D and of a hot quench water draining line 2.

[0214] In another embodiment, the dewatering bin unit G can comprise two or more dewatering bins G.

LIST OF REFERENCE NUMERALS

[0215] ECHO system [0216] X coke drum unit [0217] A transition piece [0218] B mixer [0219] C coke crushing unit [0220] D closed sluice way [0221] E slurry basin [0222] F slurry pump [0223] G dewatering bin unit [0224] H vibration feeder [0225] I drain water basin [0226] K drain water pump [0227] Q hydrocyclone [0228] O dirty water pit [0229] P dirty water pump [0230] L clean water tank [0231] M transport water pump [0232] N air cooler [0233] R cutting pump [0234] S quench water pump [0235] V1, V2, V3, V4 valves [0236] 1 quench water supply line [0237] 2 hot quench water draining line [0238] JP joining point [0239] 3 cooling water line [0240] 4 flushing line [0241] 5 slurry line [0242] 6 drain water supply line [0243] 7 drain water discharge line [0244] 8 clean water supply line [0245] 9 dirty water supply line [0246] 10 solid particle discharge line [0247] 11 sludge line/dirty water supply line [0248] 12 cooling water backflow line [0249] 13 make up water supply line [0250] 14 cutting pump water line [0251] 15, 15a-d vent collection lines