Harvest all at once. New application and new product

Transcription

1 Harvest all at once The compact harvesting principle / Potential evaluation for biomass production / Review and current activities / Re-design of combine harvester is prepared / Interesting approaches to economic evaluation The biomass potential of chaff and a principle of co-harvesting - practically free of charge - have been described in two former publications (German magazine BauernZeitung 30, 31/2010, pp. 28, 29 und pp. 30, 31). Meanwhile, the planned combine harvester re-design is prepared. The realization is scheduled in harvesting period of The design regarding the proposed new harvester machine and its testing are primary targets of all further work. The technical solution itself is not the subject of this article. Figure 1: Demonstration of volume ratios in the mixture New application and new product On the one hand, the proposed method is depicted to give a better understanding of the processes. After many conversations presenting the new approach it seems to be necessary for several reasons. On the other hand, a change or simplification of the cereal harvest process, memorized for decades, is difficult to understand without pictorial representation. Furthermore, every conversation inevitably leads to a comparison between the existing and the new design of the combine, even if this is factually incorrect. The process considers the design of a new application chain using a partially other product. Therefore a specialized harvester that is able to provide the modified product is the key machine. The fundamental differences between the two process chains will be illustrated.

2 Introducing here the new name of compact harvesting, the method takes into account following issues: The total harvest process is realized in more compact way (a separated straw harvest chain is not necessary), the process in the combine is more compact (shaker and winnowing units omitted), and the harvested product mixture is compressed for temporary storage in a bunker, transportation or storage in general, if necessary. This comparison was done in collaboration with the University of Applied Sciences Schmalkalden (FH, Faculty of Mechanical Engineering, research group Renewable Resources, Nawaro ). The FH Schmalkalden also provides support by doing the re-design of the combine harvester. The compact harvesting method provides a new approach for the crop harvesting process, machine and product. The prime process focus is in harvesting the grain as well. In just one passage: Grain, straw and chaff New is the approach of harvesting a mixture that contains the desired grain, straw (a certain share only), and chaff in a single passage. Thus, the entire share of sustainably removable biomass is harvested in a single process. Only the acceptable amount of harvested straw is taken away in order to assure a well-balanced humus level in the soil. The rest remains on the field. Due to the chaff the proportion of harvested biomass by chaff is higher. This supports the goals of energy crop cultivation providing a new biomass potential. It ensures a possible expansion of bio-energy without new acreage conflicts, which are driven by limited areas available for energy crops. Figure 2: Schematic illustration of the compact harvester Recent industrial developments in the use of this potential for pilot plants already calculate with annual tonnages of four-and five-figure range (e.g. Bioliq process of the Karlsruhe Institute of Technology, KIT). If agriculture wants to be considered as a serious partner in energy policy change, it

3 must stand the unavoidable cost pressure concerning technics and technology and provide low-cost biomass for energy purposes. It is difficult to communicate to industrial partners prices for a ton of straw coming from the neighborhood that are above the overseas coal price level! What the farmer or provider needs is a safe harvest technology, which makes the overall process as efficient as today the combine. Such an approach was proposed with the compact harvesting method (Figure 2). A new market should be opened It is not the goal to undermine the current market for grain and straw products. The aim is to open a new farmers market for biomass products especially for chaff as a high-quality and therefore future demanded product It is recognized, that compact harvesting technically provides the number one chance. In articles published last year in the farmers' newspaper (BauernZeitung) were described the background of the idea to use chaff and short straw, and the technical approach to modify a combine harvester. Not the modified harvester represents the star of the new method, but an additional cost-efficient biomass product in form of straw / chaff (Figure 3, p. 32). A first direct comparison should determine whether the new method can be implemented at the same cost or even cheaper than current processes. The comparison is subject to the following assumptions: Performance and cost of the combine and compact harvester are initially identified as equals because the compact harvester is based on the same platform of a conventional combine harvester. As a result of technological development, constraints in performance and cost for the new harvesting machine are not expected. Actual values for the compact harvester are determined with the prototype at a later date. The conventional collecting line of straw (square bales) was defined by the process steps pressing, collecting, loading, and transporting. No. STEP (conventional) COST [ ] For [t] Comments 1 Combining 1, Transport (grain) Grain, 20 ha 3 Straw collection Straw when using 25% 4 Straw transportation Grain winnowing for storage , rides 190 t of biomass Costs per ton of grain , for 160 t of grain Costs per ton of straw for 30 t of straw No. STEP (compact harvesting) COST [ ] For [t] Comments 1 Harvesting 1, Transportation (mixture) Separation of mixture , rides 220 t of biomass Costs per ton of grain , for 160 t of grain Costs per ton of straw for 60 t of straw/chaff

4 Table: Results of comparison The bale storing is not considered in the conventional method, because it is not required after stationary winnowing when compact harvesting is applied. After harvesting with the compact method the straw is already downsized and can directly be fed into a final process stage. If the final product were pellets, for example, the bale line would in fact incur considerably additional burdens for removal from storage, ball-breaking and fine grinding. In both examined processes, the grain processing includes the winnowing. Even if in conventional technology the winnowing procedure is usually not a farmer s job, those costs are quoted to him in form of discounts. The approach for numbers and data bases on guidelines of The Association for Technology and Structures in Agriculture (KTBL) and on a field size of 20 ha. An exception to this approach represents the cost of winnowing which is quite different in many publications. In the presented case, the value in compact harvesting was determined according to the price list of a grain merchant plus an extra fee for necessary pre-winnowing caused by heavy contaminants. In the process diagram (Figure 3) the calculation points are marked for comparison purpose. The underlying data and calculated values are assigned to calculation points in the table. The calculation is done deliberately using a small number of clear points of comparison. The stated aim is a first "stress test" for the compact harvesting method. For a first calculation the assumptions are very conservative in order to not distort the comparison with exaggerated positive aspects. Nevertheless, there is the conviction that the process and its development will reveal considerably more potential.

5 At first, lower overall cost First of all, despite higher costs in separation, the total costs in compact harvesting of about / ha are lower (about 10%) because of the omission of the bale processing line. This is respectable for a first approach. Also in compact process, grain represents the main part of the harvested biomass. Chaff and straw are additionally harvested at the same time. Therefore, there are limits for a total cost reduction which are determined by harvesting costs of grain. The grain share related costs are therefore equal in both processes and amount to / t in present case. It would be also possible to divide the total cost, by weight of individual components of grain, chaff, and straw on the mixture. This would in terms of figures - result in a cost reduction for the grain portion. It is not the approach here. Figure 3: Compact Harvest - Calculation points for comparison of methods In this new approach, the co-harvesting cost for straw and chaff components in the mixture results from the difference between total and grain harvesting costs. Before discussing further details an explanation regarding the cost approach of subsequent separation process is required as follows: A dealer of agricultural products could as a service provider in worst case calculate a basic price of 3.00 / t for separation service of the total mixture volume of 220 tons (grain, straw, and chaff) plus an extra fee for winnowing grain impurities of 1.00 / t. This would result in a total of 880 for the winnowing, e.g. the separation of chaff and straw from grain. The pragmatic farmer will receive according to present interpretation of the price table a basic price plus extra fee for each ton of grain which results in the more practical amount of 480. At this point in the process, the difference shows considerably hidden potential that is a worthwhile attempt for further development: It is possible to approach the practical process by a powerful prewinnower for the specific mixture. For the time being, to get an evaluation of the new method both of these observations have been considered as not entirely fair: Due to the fact that the total amount of mixture (220 t) runs through the additional pre-winnower, the entire volume is calculated with

6 1.00 /t. The subsequent grain winnowing stage does not differ from the conventional winnowing process. 160 tons of grain are rated with 3.00 /t which results in 700 in total. So, the higher winnowing effort is measured in this comparison at the same time. Thus in the overall result for the co-harvesting of straw-chaff mixture (60 t) the operation costs are of / ha compared with / ha for straw harvesting (30 t) in the conventional example. Just this fact represents a very significant cost reduction. Since the collecting of chaff doubles the amount of harvested straw volume, the cost reduction for each ton of crop turns out to be even more remarkable in this specific consideration: Costs of 5.59 / t straw-chaff mixture in compact harvesting faces / t straw in conventional harvesting methods. This corresponds to a specific cost reduction by 70%! Due to known values for the high volume of straw and chaff, the associated costs and experiences with regard to transport, handling and storage, this result was not expected and could hinder the understanding of the process for some practitioners. To clarify the issue we bring up a "volumetric chaff formula" (Figure 1, p. 30). Self-compacting the mixture Although at first sight, such a pictorial view is easy to understand: The formula states that 0,5 units of volume of each, grain, chaff, and chopped straw can be mixed to only 1,0 unit of volume in mixture filling smaller particles in empty gaps between bigger components. This can be easily found out in a simple experiment. Interestingly, this mixture is nearly self-compacting as well. This causes three main effects to the process: A good realizable bunker volume of about 35 m³ is sufficient for the harvester to collect the total biomass harvested from one hectare. Thus the compared compact harvester must be unloaded only once per hectare. The mixture volume allows using not only the maximum transportation weight according to the vehicle regulations of the road traffic licensing authority (StVZO), but also the possible transport volume. This means that even in this case, three bunkers can be loaded on a transportation unit. In comparison, a transport unit can be calculated with 25 tons of loading capacity. This then results in the aforementioned superior values. The mixture can be conveyed very well mechanically and pneumatically which also matters for the technical implementation of the harvesting process. What does the procedure bring in terms of chaff co-harvesting? A considerably great contribution, when considering straw / chaff to pellets as output product. On current basis again fairly calculated, out of the additionally collected 1.5 t / ha chaff, an extra profit of 90 / ha is realistic. This only concerns the use of chaff as additional biomass harvested for the production of agropellets. Added to the procedural cost advantages and its future potential as well as the cost savings in the pellet production an extra benefit of 150 / ha can be realized as a result of shredding the straw already in the harvester (eliminating the shredding during pelletizing

7 process). This has been indicated last year and is properly verified as achievable. We should be able to indisputably accept the economic opportunity as the second chance of the process. This stress test to position the activities for the first time - must be assessed as passed. With the compact harvesting method besides the conventional process by combine harvesters, a technically and economically equivalent method has been proposed that really has comprehensible potential. The procedure is consistently applicable in the farmers works and is not a supplemental or special solution. By reducing operation costs on the one hand and additional profits that result from the consistent co-harvesting of the whole available biomass volume on the field on the other hand, both farmers and users obtain new sustainable options: The farmer gets the chance to enter - as a long-term partner providing raw materials - the currently interesting process of change in energy and raw material supply. This can be done operationally by very specialized service providers. Apropos, similar experiences have been done by beet farmers. The service provider can become owner of the complete process offering services from harvesting, transportation, storage of the mixture up to its subsequent processing. Here, creativity frame work in large scale exists up to the final product which opens up new possibilities rather than only focusing on better utilization of existing machines. Farmers and service providers can develop new markets together. A great number of companies of the extractive and energy industry welcomes and supports this development. Initial project plans following this direction have been noticed very positively. Chaff has also confirmed its excellence by an industrial-scaled test. In presence of suitable harvesting equipment, the extraction of chaff and broken straw can be additionally implemented in grain production. It generates another product, without entering into competition for fields or the need to establish new methods of cultivation. The compact harvester thus represents the key machine of the presented process chain. Just imagine: the new process would be completed at the interim storage box on the field. At this interim storage, a time-shifted production process can start that uses mobile processing (e.g. production of pellets). This would require that the described crop mixture may be stored over several months without significant losses. In Bernburg, the mixture s storage suitability has been tested last winter. The partly surprising outcome of those storage experiments are subject of a future publication. It also includes the topics of humus and moisture of straw. DR. JOHANN RUMPLER, Regional Institute for Agriculture and Horticulture Saxony-Anhalt (LLFG) BERNBURG, PROF. FRANK BENEKE, University of Applied Sciences Schmalkalden (FH) SCHMALKALDEN