PTQ Q1 2023 Issue

V6 (water)

V7 (water)





Coal tar uid inlet

Filtered coal tar uid to preheater of HDS reactor




Solid sludge discharge

Figure 1 Universal Filter for HDS reactor of coal tar liquid

from refineries or petrochemical plants meet these FM requirements. So far, all commercial applications are suc - cessful, as shown in the ensuing discussions. Treatment of a light coal tar feed stream to HDS reactor As shown in Figure 1 , approximately 52,000 MT/Y of light coal tar from a steel mill is fed to first chamber C1 and sec - ondly to chamber C2 (of the Universal Filter) through valve V1 for removing the solid particles from the liquid stream. The filtered liquid is then transferred to an HDS reactor via valve V2. During the regeneration cycle, water through valves V6 and V7 is used to flush out the solid sludges in both chambers and discharged via valve V5, while valves V1 and V2 in the process side are closed. To test filter performance, the filter was on-stream con - tinuously for 45 days, treating 6,529.6 metric tons (145.1 MT/D) of light coal tar liquid without regeneration (back - washing). Liquid coal tar samples containing 92% benzene, 5% toluene, and other C6-C7 naphthas were collected from

inlet and outlet streams of the filter. A sample of solid slurry accumulated in the filter during the operation was also col - lected simultaneously for testing and analysis.  Percent and types of solid removal from process fluid by Universal Filter: From analysis of the filter inlet and outlet liquid samples, it was determined that as high as 97.6 wt% of the sol - ids were removed by the filter, based on the following measurements: Weight of total solids collected from 13 litres inlet liquid sample: 0.5877g Weight of total solids collected from 13 litres outlet liquid sample: 0.0144g Wt% of solid removal by Universal Filter: 1 - (0.0144/0.5877) = 97.6 wt% XRF analysis in Table 1 shows that the filter can effectively remove all types of solids, including FM and diamagnetic (DM)/paramagnetic solids, through induced magnetism with the FM inducing agents under an external mag - netic field in the filter. Surprisingly, removals of Fe, S, Mn, Mo, and Cu were almost complete (100%), Al and Cr were around 90%, and Ni and Cl were 60-70%.  Nanometer particles removal from process fluid: The following procedures are used to directly measure PSD in the liquid streams: • Inlet liquid sample was shaken with an ultrasound vibrator for a few minutes to break up any lumps or coagulates of the solid particles • PSD of one portion of the shaken inlet liquid sample was immediately measured with the laser particle anal - yser Horiba LB550. The PSD analysis is presented in Table 2 .  The other portion of shaken inlet liquid sample was allowed to settle for 30 minutes before analysing the PSD. The PSD curve is plotted in Figure 2 .

XRF analysis showing solids removal by Universal Filter

Element Content in inlet liq. Content in outlet liq.

% Removal

(0.5877g) *

(0.0144g) **

by filter


26.86 wt% 9.49 wt% 843 ppm 0.43 wt% 0.53 wt% 224 ppm 1,529 ppm 1,337 ppm

12.67 wt% 14.78 wt%

98.9 96.2





Al Cr

2.16 wt% 2.14 wt%

87.6 90.0




Ni Cl

1.57 wt% 1.92 wt%

74.4 64.4


220 ppm



* Total solids in 13 litres of inlet liquid to the filter. **Total solids in 13 litres of outlet liquid from the filter.

Table 1


PTQ Q1 2023

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