Guan Shanyuan from China-Africa Agriculture Investment Co., Ltd. (CAAIC)
Our sisal farm in Tanzania has introduced practical technologies from China and is adopting targeted technical innovation in light of local conditions, with a view to reducing production and operation costs, boosting yields, and improving quality and return on investment.
●Modification of sisal scraper
●Modification of sisal fiber baler and introduction of a new one
●R&D and application of ridger especially for sisal cultivation
●Improvement in design parameters of trailer specially for sisal leaves
●Enhanced production process control to improve the quality of sisal fiber
In Tanzania, sisal was first cultivated at the end of the 19th century and flourished at a fast pace thanks to the suitable climate and soil. Towards the early 1960s, Tanzania has evolved into the world's largest sisal producer and sisal fiber exporter, with an annual production of sisal fiber at 280,000 tonnes, making it the "Kingdom of Sisal". Since the 1970s, the sisal industry in Tanzania has seen a sharp contraction, with the number of sisal farms decreasing sharply from 172 at its peak to 38, and the annual production of sisal fiber also dropping markedly to about 35,000 tonnes today. Among the reasons, the frequent aging failure of processing equipment, extensive management, and lower yield per unit area are the major problems facing the country. Precisely because of this, CAAIC's sisal farm in Tanzania has introduced practical technologies from China and is adopting targeted technical innovation in light of local conditions, with a view to reducing production and operation costs, boosting yield, and improving quality and return on investment.
Modification of sisal scraper
Currently, the sisal scrapers used in the sisal industry in Tanzania are basically the models produced before the 1960s, namely, the Corona II and Corona IV manufactured by Krupp Grusonwerk AG, Germany, with intermediate transitional and modified models for the rest. There are a variety of models, but the equipment is aging with frequent failures, high energy consumption, and critical shortage of accessories. For the CORONA II type, there is little difference between the large and small cutter wheels, and the method of scraping is "leaf base first and leaf tip later"; conversely for the CORONA IV type, the large and small cutter wheels largely vary, and the method of scraping is "leaf tip first and leaf base later".
The complete set of sisal scraper is composed of the drive system, leaf feeding system, rope wheel clamping system, cutter-wheel recessed scraping system, flushing system, fiber extraction system, and others. The drive system of stationary sisal scraper used in Tanzania's sisal industry was traditionally single-machine flat belt driven, with the defects reflected in high energy consumption, use of consumables, time-consuming maintenance, and unsafe operation. Starting with the reconstruction of sisal processing equipment, CAAIC has transformed the use of single motor and wide flat belt drive to independent motor for both large and small cutter wheels and V-belt drive for its sisal farm. Based on the size of the cutter wheel and the scraping position, two low-power motors are used to replace one high-power motor; the spacing between the driving shaft of the motor and the driven shaft of the cutter wheel is narrowed to reduce consumables; and the V-belt is used for the replacement of the wide flat belt. In doing so, the sisal farm is allowed to lower production costs, increase operating efficiency, and thus improve return on investment.
The achievements in technical innovation are remarkable. There are three resulting economic benefits: first, consumables are reduced. A sisal scraper originally required a wide flat belt with a length of 60m and a width of 30cm every quarter. Now, only six 2.5m V-belts are needed every six months, without the need of crab shell bolts, belt wax, and others; second, the time is saved. Six hours on average every week was spent repairing the belt. Now, it only takes four hours to replace the belt every six months; third, the electricity cost is saved. When it comes to the calculation of the electricity cost in Tanzania, it is not only based on the "kWh" of the power consumption, but also on the "kVA" measured for instantaneous current intensity. After the transformation, two motors are started in steps, reducing the instantaneous current intensity to save the electricity cost. From the perspective of safety and working environment, the breakage of wide flat belt now and then during its high-speed operation is avoided and the work safety environment is improved. The use of V-belt also allows for the significant reduction of noises.
Modification of sisal fiber baler and introduction of a new one
The sisal fiber balers currently used in Tanzania are British products made in the mid-1950s, with the drawbacks highlighted by seriously aging equipment, an acute shortage of spare parts, hard-to-maintain, and especially, the frequent failures of the hydraulic system. To this end, we have worked with Hebei Handan Golden Lion Cotton Machine Co., Ltd. (hereinafter referred to as "Golden Lion"), a holding company of Sinocot that is part of China Co-op Group under the All China Federation of Supply and Marketing Cooperatives, to carry out the technical transformation. Golden Lion is hailed as the "Cradle of Cotton Machine in China", and exports its products to 42 countries and regions across the global. According to the requirements of large diameter and fast speed of the existing equipment plunger, Golden Lion completed the replacement with a new hydraulic system, an electrical control operating system, and hydraulic cartridge valves with large throughput and excellent sealing in January 2007. The modification has allowed to greatly shorten the baling time, reduce the failure rate, and achieve a good effect.
To satisfy its development needs, CAAIC also purchased the new BY5000C Sisal Fiber Baler for its sisal farm from Golden Lion. This type of sisal fiber baler features high tonnage (5,000kN), high density for bales (480 kg/m3), high efficiency (15 bales/h), excellent rigidity and stability, simple operation, convenient maintenance, and more. The door is opened and closed in a form of a combination of manual and hydraulic operations to improve safety. The hydraulic system comes equipped with cartridge valves to accommodate the characteristics of large throughput and good sealing. The sisal fiber baler is electrically operated, with a slant-axis plunger pump and a double vane pump for its main pressure system. The control valves mainly adopt two-way cartridge valves and unloading valves, which are automatically controlled to reduce labor intensity and were installed and commissioned on the farm from October 2013 to April 2014.
Right after it got the news, Mohammed Enterprises Tanzania Ltd. (MeTL), the largest sisal cultivation and fiber producer in Tanzania, learned about Golden Lion and its equipment repeatedly. After comparison and crosschecks, it eventually commissioned Golden Lion to modify all the sisal fiber balers in its six farms from October 2016 to May 2017. After installation and commissioning, the lifting time of the modified baler plungers was shortened from 8-12 minutes to about 3 minutes, together with a more compact and consistent form factor of bales and more convenient maintenance and repair. R&D and application of ridger especially for sisal cultivation
Sisal is a tropical plant. After planting, juvenile sisal needs to be nourished and managed for 3-4 years to enter the harvest period. Generally, they are eliminated after 9-12 years of harvest. The production of sisal fiber is closely linked to the harvest area, age of sisal fiber, number of live plants per unit area, and sisal fiber growth (varied depending on soil, terrain, climate, and field management). The rate of leaf yielding fiber and quality are greatly different. The sisal is usually cultivated on flat ground and in wide and narrow rows in Tanzania, that is, after the land is raked, the sisal is planted according to the specified standards of 400cm for wide rows, 100cm for narrow rows, 100cm for plant spacing, and the presentation of isosceles triangle between plants each row. Sisal is grown under a fibrous root system, without taproots. It is basically distributed horizontally in the soil and has the characteristics of shallow roots and good aeration. Generally, more than 90% of the roots are concentrated in the 0-30cm surface soil layer, with a small amount extending to 50-100cm. For planting on flat ground, the growth of the sisal root system will be restrained due to the affected respiration as a result of excessive soil moisture in the rainy season, and is especially susceptible to diseases such as zebra patterns.
In recent years, affected by the global warming and poor drainage in the field, the survival rate of transplanted seedlings of sisal immersed in water stain has been significantly reduced. In the rainy season (from January to May) in 2014, the 200 hectares of sisal gardens of CAAIC's sisal farm suffered from floods to varying degrees, with a loss of RMB 2.5 million. For this purpose, the farm purchased a ridger from China at the end of 2014, aiming to plant sisal after ridging. It turned out that the ridger could not achieve the expected effect. Manual ridging is labor-intensive, time-consuming, and expensive (with the ridging cost at about RMB 1,500 per hectare). Similar equipment has neither been used in other sisal farms in Tanzania nor been available in the market.
In the face of difficulties, the sisal farm of CAAIC organized a special squad for independent research and development. The expected design objectives were achieved in the end through repeated commissioning. Being put into service, the independently developed ridge shows good ridging effect, with an average ridging height of 28cm. With high efficiency, a single ridger is able to ridge 5 hectares per day, and the ridging cost stands at about RMB 300 per hectare. Compared with the flat planted sisal, the survival rate of ridged sisal rises by 5-40% (with large difference between different terrains), the number of leaves of a single plant goes up by 5 to 20, and the leaf area rises is increased by 20-90%. The plants are stout and bright in color, and their effect is significantly better than that of the flat planted sisal. Since 2016, the 700 hectares of sisal planted on the farm have all been ridged by this type of ridger. Improvement in design parameters of trailer especially for sisal leaves
Traditionally, the sisal farms in Tanzania transported sisal leaves from the field to the processing plant by small train, which has been gradually eliminated today. Now, various types of trailers are used for loading sisal leaves. At the very beginning, the sisal farm of CAAIC used the single-tire platform trailer purchased from China, but found that it was less loaded and the leaves were easy to slip after the trailer was put into service. Afterwards, the farm contacted the trailer manufacturer Beijing Jingtuo Weiye Trailer Co., Ltd. to improve the design parameters and change the platform to concave type—20cm wide sub-panels were added to both sides of the vehicle bottom, the single tire was replaced with double tires, and baffles on both sides were removed. It turned out that there remained some problems: The first is that the strength of the traction frame was insufficient, the second is that the concave base plate was prone to water accumulation in the rainy season, resulting in mildew of the leaves, and the third is that the strength of the axle was not enough. After receipt of the farm's feedback, the manufacturer eliminated the original defects by improving the strength of the traction frame and axle and reserving holes on the base plate for draining the water. During the service, it was also found that the steel wire tire was more easily punctured by the shrub pile in the field, so the manufacturer was required to have to provide optional 12 layers of wire tire.
Enhanced production process control to improve the quality of sisal fiber
In spite of basically identical raw materials and production processes, the price of sisal fibers of different grades varies greatly, and the unit price of the top-quality sisal fiber is about 3 times that of the defective product. The sisal farm of CAAIC fully realized the extreme significance of the quality of sisal fiber to its survival and development. Therefore, a package of management measures for quality improvement was developed: First, strictly control the quality of cutting leaves, including the quality requirements for circle cutting, cut-through, 45 degrees, no rotten leaves, no short leaves (＜60cm), and others. The site management personnel should often visit the field and make unremitting efforts to address possible problems; second, timely and accurately regulate the connection between the cutting and scraping processes, so as to prevent the cut leaves from getting moldy as a result of an extended pile-up period due to failure of timely processing; third, specially designate one person to pick inferior products at the wet fiber exit end of the sisal fiber scraper; fourth, spread and dry wet fibers in a uniform and neat manner, pick the defective fibers (UF) in the drying field, and collect and store dry fibers in the granary in time; fifth, stringently control the polishing quality. Each bundle must be evenly polished inside and outside. The sorting quality shall be strictly controlled. The unqualified fibers shall be cut off with scissors, the random inspection shall be intensified, and they shall be re-sorted if any unqualified fiber is found; sixth, the calibration of scales is normalized, and the packaging of different specifications should be randomly inspected. Unqualified products must be reworked. After continuous efforts, the quality of sisal fibers produced by the farm comes out at the very top in the industry, which is favored by users.
Li Zhenxiu, engineer of Hebei Handan Golden Lion Cotton Machine Co., Ltd., provided some information available to the section of "Modification of sisal fiber baler and introduction of a new one".
Source: China Investment