Comparation on cost and energy consumption with different straw's collection-store-transportation modes

Abstract: In order to select appropriate mode of crop straw’s collection-storage-transportation, and promote the large-scale use of straw resources, the mathematical model about straw’s collection, storage and transportation was established, which was based on the equipment, manpower, and cost on the North China Plain. By analyzing different modes about straw’s collection-storage-transportation (which was divided into centralized model, decentralized mode; collected by manpower, collected by machinery), the effect of cost and energy consumption were different. Because of the different amounts of straw collection, manpower and equipments were demanded in mathematical models. The results showed that the cost of straw’s collection-storage-transportation was 120- 260 Yuan/t, the fuel consumption of straw’s collection-storage-transportation was 1.2×105 - 5.5×105 kJ/t. While using machinery to collected straw in filed, the cost was lower than that by manpower; but the required equipment number was significantly more than thatneeded by manpower. Meanwhile, the energy consumption of equipment was significantly increased. On the contrary, collecting straw in filed by manpower needs a lot of manpower. The calculated results showed that the cost and energy consumption of centralized mode about equipment-manpower- cost was lower than decentralized mode when collecting by the same manner. Compared to the manpower collection, collection by machinery can reduce the total cost, but the initial investment was higher and the capacity in solving employment problem was lower. When the amount of crop straw collection increased from 5×104 to 50×104 t, the unit cost of mode A and B was monotonically increasing. As to mode C and D, it declined quickly from 5×104 to 25×104 t, then rose gradually from 25×104 to 50×104 t. Therefore, it can be concluded that the collection methods affected cost extremely. Collecting straw by manpower, the mode of A and C curved intersect at 250 000 t; Or else, the mode of B and D curved intersect at 500 000 t. When the collected amount of crop straw increased from 5×104 to 50×104 t, the unit energy consumptions of mode A and B increased, with slow upward trend rate; On the contrary, from 5×104 to 25×104 t straw collection, the unit energy consumption of mode C and D was decreasing, when the collected amount of crop straw was 18×104 and 12×104 t, the unit energy consumption curves of mode B and C2 could intersect; Similarly, the unit energy consumption curves of mode A2 and C1 also could intersect. In this circumstance, when the collected amount was less than the intersection, the energy consumption of mode B and A2 was lower than mode C2 and C1. Therefore, the energy consumption of centralized mode is lower when the crop straw amount collected is less, it is recommended to choose centralized mode; Otherwise, decentralized mode is the better choice.