In order to improve energy utilization rate of biogas engine-driven heat pump (BEHP) systems for wastewater treatment plant, the exergy analysis is applied in this paper. The paper concludes the exergy losses and exergy efficiency of each equipment, and reveals the weak link of energy transformation of the whole system. According to the calculation of one example, the location of maximum exergy loss is the biogas engine-driven, while the location of minimum exergy efficiency is the compressor, which provides powerful theoretic references to improve and optimize BEHP systems for wastewater treatment plant.

Abstract. The fruit images on points cloud acquired by the current 3D scanner from field will appear a visible seams, inconvenient data acquisition or taking large space due to unorganized background. We give a SAOW method to cope with the space efficiency and realistic effects of texture synthesis on pear point model. At first, a point-quadtree is proposed to simplify the pear image division. Then, an adaptive multi-granularity morton coding scheme are presented to optimizing the memory space of pear image. At last, weighted oversampling mixing method is mainly focused on texture quality of pear surface. As shown in the experiment results, our adaptive division makes the memory space decline dramatically about 90.7% than non-division and 92.9% than general division respectively; adaptive code scheme helps to reduce the memory to 72.1% of ordinary morton code; weighted oversampling keeps the mixed texture more real and smoothly than current methods.

Based on the MEOR mechanism study of Brevibacillus brevis and Bacillus cereus, From 2002 to 2004, the two strain and other microbes were applied in the microbial huff and puff as well as the Microbial enhanced waterflood test in Daqing excessively low permeability (1.0md-25md) reservoir. After bacteria injection, 44 among the 60 huff and puff wells shows a significant oil production response---the accumulative oil increment reaches 9175.5 tons and the input-output ratio amounts to 1: 8. The Microbial enhanced waterflood test carried out in June 2004 also provides a satisfying result. After the injection of bacteria, the pressure in the two water injectors decreased more than 2MPa, which results in an injection capacity increase. The Analyse result of production fluid indicate that the selected bacteria can adapt the stratum conditions better and can grow and reproduce . They degrade heavy hydrocarbon , improve character of crude oil and metabolize active substances. The fluid production of trial field increase and water cut decline . in late 2005 , 7 production wells among 10 production wells get good effect . Fluid production increased from 50.7 tons per day (before bacteria injection) to 68.3 tons per day, and the corresponding water cut declined from 46.8% to 40.3%.oil production is increased from 24.7 tons per day (before bacteria injection) to 40.8 tons per day. The accumulative oil increment more than 5800tons and the input/output ratio is 1:5. These make MEOR a very promising and effective oil recovery method in Daqing low permeabilityreservoirs. Introduction Reservoirs' stratum conditions are different. The geological conditions of some reservoirs are good, and it is somewhat relatively easy to exploit crude oil, but some are poorer with poor physical properties, low permeability, narrow, small and changeable sand body, high oil viscosity and low fluidity. Moreover, there are pollution and other influential factors during drilling and water injection. Therefore, higher kick off pressure is needed for reservoir development, and it is difficult to inject water. Due to higher injection-production ratio, the effective driving system cannot be established easily. So, oil producer response is poor, production reset is slow and single well production is low. Daqing periphery oilfield belongs to " 3 low oilfield", namely, low permeability, low reserves abundance and low well production. The annual output of the periphery oilfield has reached 500×l04t, which contribute to the total production of Daqing oilfield. Due to the unfavorable conditions mentioned, the development results are not ideal. It's urgent to explore new economical and effective development mode and improve the oil recovery further. In recent years, MEOR has entered a new development period with successful applications in some countries[1–16], and the potential for the application of MEOR is fine in the near future. However, the thorough research on MEOR mechanisms is not enough, and the success rate of application is still not high enough to greatly increase oil recovery factor. This paper is about the research on the mechanism of Brevibacillus brevis and Bacillus cereus degrading petroleum hydrocarbon[17], and with the application of these two kinds of microbes, MEOR field test has been implemented successfully in Daqing peripheral low permeability oilfields.

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