Algal capture of carbon dioxide; biomass generation as a tool for greenhouse gas mitigation with reference to New Zealand energy strategy and policy

The use of algae to capture carbon dioxide as a method for greenhouse gas mitigation is discussed. A small fraction of the sunlight energy that bathes Earth is captured by photosynthesis and drives most living systems. Life on Earth is carbon-based and the energy is used to fix atmospheric carbon dioxide into biological material (biomass), indeed fossil fuels that we consume today are a legacy of mostly algal photosynthesis. Algae can be thought of as marine and freshwater plants that have higher photosynthetic efficiencies than terrestrial plants and are more efficient capturing carbon (Box 1). They have other favourable characteristics for this purpose. In the context of New Zealand energy strategy and policy I discuss progress in growing algae and seaweeds with emphasis on their application for exhaust flue carbon recycling for possible generation of useful biomass. I also introduce schemes utilising wild oceanic algae for carbon dioxide sequestration and the merits and possible adverse effects of using this approach. This paper is designed as an approachable review of the science and technology for policy makers and a summary of the New Zealand policy environment for those wishing to deploy biological carbon sequestration.     

Investigating why recycling gravity harvested algae increases harvestability and productivity in high rate algal ponds

It has previously been shown that recycling gravity harvested algae promotes Pediastrum boryanum dominance and improves harvestability and biomass production in pilot-scale High Rate Algal Ponds (HRAPs) treating domestic wastewater. In order to confirm the reproducibility of these findings and investigate the mechanisms responsible, this study utilized twelve 20 L outdoor HRAP mesocosms operated with and without algal recycling. It then compared the recycling of separated solid and liquid components of the harvested biomass against un-separated biomass. The work confirmed that algal recycling promoted P. boryanum dominance, improved 1 h-settleability by >20% and increased biomass productivity by >25% compared with controls that had no recycling. With regard to the improved harvestability, of particular interest was that recycling the liquid fraction alone caused a similar improvement in settleability as recycling the solid fraction. This may be due to the presence of extracellular polymeric substances in the liquid fraction. While there are many possible mechanisms that could account for the increased productivity with algal recycling, all but two were systematically eliminated: (i) the mean cell residence time was extended thereby increasing the algal concentration and more fully utilizing the incident sunlight and, (ii) the relative proportions of algal growth stages (which have different specific growth rates) was changed, resulting in a net increase in the overall growth rate of the culture.     

PETROPHYSICS OF LOWER CRETACEOUS PLATFORM CARBONATE OUTCROPS IN PROVENCE (SE FRANCE): IMPLICATIONS FOR CARBONATE RESERVOIR CHARACTERISATION

High resolution petrophysical analyses were carried out on Urgonian (Lower Cretaceous) carbonates from outcrops in Provence, SE France. Porosity and permeability were measured on 541 plug samples selected from grain‐supported carbonates analogous to those in the age‐equivalent Shu'aiba and Kharaib Formation reservoirs in the eastern Arabian Plate. The sampling strategy allowed property heterogeneities from centimetre to kilometre scales to be investigated, as well as correlations between porosity and permeability in several different reservoir rock types. Property spatial modelling sensitivity analyses were also undertaken. The relative abundance of microporosity, grain size and sedimentary‐diagenetic anisotropy were the main geological parameters which controlled the petrophysical characteristics of the grainstones studied. Increasing microporosity decreased permeability but resulted in an increase in the homogeneity of the reservoir rocks and therefore in their predictability. An increase in grain size, from fine sand to gravel, and in the amount of intergranular pores, enhanced permeability significantly but resulted in a decrease in the homogeneity (and therefore predictability) of the reservoir rock. At a plug scale, poro‐perm relationships are very good and can be used predictively for fine grainstones dominated by microporosity; but relationships are moderate to weak for coarse rudstones with mixed pore types, including intraskeletal pores. In grainstone units, weak sedimentary anisotropy, such as decametre‐scale cross‐bedding, did not prevent the prediction of the horizontal property distribution from vertical data over a few hundreds of metres. In these units, the lateral correlation of rock properties follows periodic variograms with a 7 m wavelength. The lateral distribution of properties in coarse‐grained and heterogeneous rudstones with complex pore types and intense sedimentary heterogeneities, such as channel structures, was however more difficult to predict from a vertical data set. Upscaling poroperm data from plug scale to reservoir scale is linear in the case of grainstones with intergranular microporosity, but is non‐linear in the case of skeletal rudstones with coarser pore types including skeletal porosity.     

自然伽马反演在双家坝构造飞仙关组鲕滩储层预测中的应用

以往川东地区飞仙关组鲕滩储层预测,主要采用常规剖面寻找"亮点"反射,或作速度反演寻找低速异常体,取得了一定的效果。但是随着勘探的深入,认识到"亮点"反射或低速异常体不一定真正是鲕滩储层的地震响应。当飞一—飞三段内发育有膏盐层或较厚的泥灰岩段时,也会形成"亮点"反射或低速异常体,如果只靠常规剖面或速度反演,就可能造成误解。针对这种情况,采用伽马反演,来排除因泥质含量增加形成的低速异常现象,再结合速度反演,较准确地预测出了双家坝地区飞仙关组鲕滩的发育情况,落实了其分布范围,为下一步勘探提供了可靠的资料。     

Iron Extraction From Oolitic Iron Ore by a Deep Reduction Process

A laboratory experiment was carried out to extract iron from oolitic iron ore by a deep reduction and magnetic separation technique. The raw coal with fixed carbon of 66.54% was used as the reductant. ...     

鄂西高磷鲕状赤铁矿提铁降杂技术研究

通过对鄂西高磷鲕状赤铁矿矿石性质的分析,总结了我国近期针对高磷鲕状赤铁矿开展的常规选矿、闪速磁化焙烧、直接还原焙烧以及微生物除磷等提铁降杂技术研究成果,并对该类矿石选矿的研究方向和前景进行了展望。     

鄂西某高磷鲕状赤铁矿浮选工艺研究

本文根据鄂西某高磷鲕状赤铁矿石的特点进行了浮选药剂及相应浮选工艺的研究,研制了EM-501脱磷捕收剂和EM-506高效脱硅捕收剂,采用脱泥-脱磷反浮选-脱硅反浮选工艺流程,取得较好的结果:铁精矿TFe品位为58.89％,TFe反浮选作业回收率为91.06％,脱泥-反浮选全流程TFe回收率为74.05％,精矿中P含量仅为0.24％.     

四川盆地铁山坡地区飞仙关组鲕滩储层地震预测

四川盆地东北部的三叠系下统飞仙关组是重要的油气储层,其储集岩体主要为经晚期白云岩化改造的鲕滩坝沉积的致密鲕粒白云岩、鲕粒灰岩.铁山坡地区位于开江-梁平海槽的东北边缘,具备发育飞仙关组鲕滩储层的条件.但是,复杂多变的围岩和严重的非均质性增加了储层预测的难度,为此,在储层预测中采用了基于信息融合理论的地质模型约束地震反演,把地质、测井、地震等多元地学信息统一到同一个模型上,将各类信息在模型空间进行有机融合,提高了反演的信息使用量、信息匹配精度和反演结果的置信度.同时,利用空间地质约束相干识别技术对储层的含气、含水及气水关系等进行了检测和识别,检测结果与钻井资料吻合.     

海相及湖相碳酸盐岩储层预测——层序地层学技术在储层预测中的应用

碳酸盐岩是非常重要的一类储层 ,应用层序地层学分析方法对碳酸盐岩有效储层进行预测是实用而有效的 ,地震参数分析方法是有效储层预测的补充方法。总体上极为致密的碳酸盐岩中 ,溶蚀性孔洞是有效储层形成的关键因素 ,而溶蚀性孔洞的发育和沉积相密切相关。在下侏罗统大安寨段湖相介屑灰岩储层的预测中 ,层序地层学储层预测方法成功地得到了运用。使用同样方法对SZ地区下三叠统飞仙关组鲕滩储层、石炭系黄龙组白云岩储层的展布作了全面的分析和预测 ,预测结果基本为钻井所证实 ,研究结果已经用于实际勘探和开发部署     

川东南地区下三叠统飞仙关组层序地层与鲕滩展布特征研究

在川东南地区,以层序地层学原理为指导,通过综合分析野外露头剖面和钻井等资料,分析了飞仙关组和鲕滩的发育特征。飞仙关组发育完整,可以识别出两个三级层序底界面,均为Ⅱ型层序的岩性、岩相转换面。第1层序海侵期主要发育混积陆棚环境,从第1层序高位期开始研究区进入碳酸盐岩台地演化阶段,鲕粒滩开始发育。第1层序高位期至第2层序高位早期,主要为开阔台地沉积环境,灰岩和鲕粒灰岩为主要岩石类型;第2层序高位晚期,沉积局限台地环境的紫红色泥页岩、白云岩夹石膏层。鲕粒滩主要发育于第1层序高位期和第2层序高位早期。第1层序高位期鲕滩呈北西—南东向展布,第2层序高位早期鲕滩则为北东—南西向展布。鲕粒滩分布以第2层序高位早期较佳,为潜在的最有利勘探层位。