C. TRATAMIENTOS POTENCIALES PARA LA ESCLEROSIS
1. Tratamientos dirigidos contra el sistema inmune
Table 4.8 shows the raw data (results) of the validation work conducted at the LASRA pilot scale fellmongery.
Table 4.8: Raw data (results) of the validation work comparing the LASRA enzyme process standard configuration (2SCrossC) and the proposed modification of its washing stages (2SCounterC). The runs of 2SCounterC R1 and R2 were runs used to generate a float to be used in R3 that was as close to equilibrium as possible (as detailed in sub-section 4.4.1 before).
ame IS (mg/l) Average IS % TS Average % TS % TKN (w/w total n
Process run
(dry solids basis) protein) Average % TKN COD (gm-3)
2S CrossC R1W1 16120 15700 6.95 6.71 2.38 2.32 59740 15280 6.46 2.26 2S CrossC R1W2 3960 4140 3.03 3.20 1.32 1.30 34740 4320 3.37 1.28 2S CounterC R1W1 20920 12090 7.53 4.87 2.33 1.53 24351 3260 2.21 0.73 2S CounterC R1W2 7120 4210 2.68 1.80 1.28 0.80 12662 1300 0.91 0.31 2S CounterC R2W1 30800 19500 10.04 6.96 3.57 2.46 112338 8200 3.87 1.34 2S CounterC R2W2 4960 3400 3.83 2.57 1.61 1.05 42208 1840 1.31 0.49 2S CounterC R3W1 7640 7880 5.07 4.74 1.81 1.79 13961 8120 4.41 1.77 2S CounterC R3W2 1640 1630 1.37 1.38 0.59 0.58 58442 1620 1.38 0.57
Looking at the COD readings found on table 4.8, it can be seen that these may not be reliably used in the analysis of validation work. Discrepancies can be seen in readings of 2SCounterC R2W1 which shows an unusually high COD value. Particularly of more concern in this work is the value of the 2SCounterC R3W2 COD value which is almost 4 times higher than that of 2SCounterC R3W1. With a multistage counter-current washing system, it is usually the first washing stage which should wash out the larger amount of organic material (solids) from sheepskins.
Table 4.9 shows the summarized results of the validation work, comparing both the 2SCrossC and 2SCounterC configuration through the measures of IS, TDS, TS, and TKN (2SCrossC is the 2-
Table 4.9: Summary of the comparison between the 2SCrossC and 2SCounterC processes using IS, TDS, TS, and TKN as measure
IS TD T
2SCrossC (% washed out per skins input weight)
2SCounterC (% washed out per skin input weight)
1.22% 1.08%
S 5.13% 5.41%
S 6.34% 6.49%
TKN 2.35% 2.45%
Table 4.9 showed (with the exception of IS) that the counter- current process extracted more TDS, TS and TKN than the cross- current process. These results validate the initial findings that the 2SCounterC configuration does yield improved quality skins. However, the improvements of the 2SCounterC over the 2SCrossC were not to the level predicted by a mass balance study. It has to be noted that the prediction generated by a mass balance study was for ideal conditions and that stringent pilot plant procedures may not have been exercised in the validation work. Also, with the measure of TDS used being a value of small magnitude, systematic and random errors may have resulted leading to a difference in results between the mass balance study and validation work.
Despite there being a small reduction of IS being washed out through the 2SCounterC, this was offset by the fact that more TDS was washed out leading to an increase of TS washed out overall.
To further emphasize the advantages of the 2SCounterC
configuration as shown by the validation work, table 4.8 showing the results of the validation work, shows that there is a higher concentration of IS, TS and TKN discharged with the 2SCrossC process over that discharged by the 2SCounterC process (for the second washing stage). For example, the concentration of TS in the effluent stream of washing stage 2 for 2SCrossC was 3.2% while for 2SCounterC it was 1.4%. With the assumption that the process floats were in equilibrium, this meant that these concentrations were consistent between the effluent and product streams. This
would mean that there is a higher concentration and also amount of IS, TKN and hence TS associated with the slats produced by the 2SCrossC configuration (with the assumption that the slats of 2SCrossC and 2SCounterC configurations had been drained to similar levels of slat ‘dry-ness’ at the end of their respective trial runs).
Overall, it is recommended that industrial scale runs be conducted in a similar fashion as was done in the validation work to test the benefits of the 2SCounterC configuration of zone 1. The results obtained would be more reflective of the potential of 2SCounterC as larger scale processing would provide more meaningful values for comparison.
4.5 Summary of Optimization Work on Zone 1 of LASRA Enzyme
Treatment Process
To end the chapter, a summary of the things achieved are seen below;
a) Forward mass balances were established in order to predict flow parameter outcomes given inputs. These forward mass balances were then used to evaluate potential modifications to the current washing step configuration (2SCrossC) of the LASRA enzyme treatment process.
b) The 2 stage counter-current washing configuration (2SCounterC) was found to be the more ideal modification to 2SCrossC
c) Through the mass balance study done on the 2SCounterC configuration, a freshwater usage reduction of up to 40% may be achieved. In addition to existing benefits of the un-optimized LASRA process, total freshwater savings over conventional is 70%.
d) Through the mass balance study done on the 2SCounterC configuration, a reduction of total dissolved solids (TDS) on the sheep slat departing the washing stages of up to 50% may be achieved (when compared with the LASRA process).
e) The finding of c) has since been validated through a trial run (although not to the magnitude predicted by mass balance). It is recommended that an industrial scale study be conducted in a similar fashion to the validation work done to confirm findings.
However, it has to be noted that for the 2SCounterC configuration to be
implemented in the industry, this may require the expansion of additional capital resources to upgrade existing pre-tanning facilities such as storage drums to store the float to be recycled. In the following chapter 5 , similar approaches, conducted to find a suitable modification to Zone 2 of the LASRA enzyme treatment process are outlined.