Cost evaluation for dry fiber production from A. comosus leaves is presented in Table 7.4. A slight increase of the production costs was found in the first crop plants compared with the plants from the second crop, which was due to the difference in productivity between both crops (Table 7.4). However, a similarity was found in the distribution of costs; fuel was the rubric which had most influence on the cost of the product, accounting for an average 70.1 % of the total cost, followed by manpower costs, with 29 % of total cost. Three workers were considered in the manpower rubric: one to operate the machine, the second to hand the leaves to the machine operator, and the third to collect and arrange plants for transportation or for drying.

Finally, the lowest cost was depreciation of the equipment with 0.9 % of the production costs. The cost of the equipment was of US$3,000 with a lifetime of 12

years which means that for plantations of 70,000 plants/ha, this rubric has little influence on the total cost. Costs of raw material or drying were not considered since the first comes from wastes and air-drying was used.

7.2 Conclusions

The quantity of leaves as well as the distribution by leaf length of A. comosus plants from the first and the second crops was different. The plants from the first crop produced less quantity of leaves per plant, therefore less quantity of leaves and less fiber per area unit (hectare). With respect to the scrapping machine prototype, pro­ductivity tests showed that the average processing capacity was 113 A. comosus plants/hour, slightly higher in the second crop than in the first crop, for the reason that the second crop plant had more leaves, thus allowing production of 4.9 kg/h of dried fiber. The fiber produced had an average 74 % moisture content and presented a greenish shade, which can be bleached with water, hydrogen peroxide 5 %, or chlorine 1 %, the most effective being chlorine 1 %, which gives the highest color change for pineapple fiber.

Lastly, a slight increase in production costs of the first crop plants was found compared with the second crop, due to the difference in the level of productivity of each type of crop. However, the distribution of costs was similar for both crops, since fuel accounted for 70.1 % of the total cost, followed by manpower with 29 %, and lastly by depreciation of the equipment with the lowest cost at 0.9 %. In addition, the average cost to produce 1 kg of dry fiber was US$0.49.