Systematic analysis and multi-objective optimization of an integrated power and freshwater production cycle

This study represents the results of the analysis and optimization of an integrated system for cogenerating electricity and freshwater. This setup consists of a Solid Oxide Fuel cell (SOFC) for producing electricity. Unburned fuel of the SOFC is burned in the afterburner to increase the temperature of the SOFC's outlet gasses and operate a Gas turbine (GT) to produce additional power and operate the air compressor. At the bottom of this cycle, a combined setup of a Multi-Effect Desalination (MED) and Reverse Osmosis (RO) is considered to produce freshwater from the unused heat capacity of the GT's exhaust gasses. Also, a Stirling engine is used in the fuel supply line to increase the fuel's temperature. Using LNG and the Stirling engine will replace the fuel compressor with a pump which increases the system performance and eliminates the need for the expansion valve. To study the system performance a mathematical model is developed in Engineering Equation Solver (EES) program. Then, the system's simulated data from the EES has been sent to MATLAB to promote the best operating condition based on the optimization criteria. An energetic, exergetic, economic, and environmental analysis has been performed and a Non-dominated Sorting Genetic Algorithm (NSGA-II) is used to achieve the goal. The two-objective optimization is performed to maximize the exergetic efficiency of the proposed system while minimizing the system's total cost of production. This cost is a weighted distribution of the Levelized Cost of Electricity (LCOE) and Levelized Cost of freshwater (LCOW). The results showed that the exergetic and energetic efficiencies of the system can reach 73.5% and 69.06% at the optimum point. The total electricity production of the system is 99 MW. The production cost is 11.71 Cents/kWh, of which 1.04 Cents/kWh is emission-related and environmental taxes. The freshwater production rate is 42.44 kg/s which costs 4.38 USD/m³.     

低阶煤颗粒-气/油泡间的诱导时间研究

为表征低阶煤颗粒-气/油泡间矿化过程的差异,通过Sutherland理论下固体颗粒进入泡沫产品的总概率(E)和浮选速率常数(k)之间关系,并结合低阶煤颗粒-气/油泡的浮选速率试验,求得了低阶煤颗粒-气/油泡间的诱导时间。浮选实验研究表明,在相同的捕收剂消耗量下低阶煤-油泡浮选产率均高于低阶煤-气泡浮选产率。诱导时间测试表明,低阶煤颗粒-油泡间的诱导时间(35 ms)要明显低于低阶煤颗粒-气泡间的诱导时间(93 ms)。上述实验结果表明,油泡表面的疏水性要强于传统浮选气泡表面的疏水性。然而,进一步利用Sutherland理论中固体颗粒进入泡沫产品的总概率和浮选速率常数之间的数学关系,并结合低阶煤颗粒-气/油泡的浮选速率试验求得的低阶煤颗粒-气/油泡间的诱导时间分别为9.67和8.46 ms,其与诱导时间测试仪分别测量的诱导时间差异很大。这主要是由于在实际浮选过程中气/油泡的上升速度分别为23.26和22.68 cm/s,其远高于2015EZ型诱导时间仪测试过程中气/油泡碰撞速度(2.0 cm/s)。因此,诱导时间理论计算表明气泡-颗粒间的碰撞速度对颗粒-气泡间的诱导时间影响很大。上述研究结果表明油泡浮选效果优于传统浮选的内在原因在于低阶煤颗粒-油泡间的诱导时间小于低阶煤颗粒-气泡间的诱导时间。     

应用组合起泡剂优化黑、白钨混合浮选

针对湖南某钨选厂使用杂醇类起泡剂BK205所产生的泡沫小、性脆、泡沫层薄等不利于二次浮选的特点,采用BK205与新型醚类起泡剂CU组合使用以便实现矿石中钨矿物的高效回收。结果表明,在采用BK205与新型醚类起泡剂CU组合质量比为3∶1、先BK205后CU的加药方式下,小型闭路试验得到精矿WO3品位为30.13%,回收率为78.98%。工业试验表明,组合起泡剂不仅改善浮选泡沫,减少药剂用量,降低药剂成本,而且能获得比原起泡剂更好的工业指标,使钨矿物得到更高效的回收。     

响应面曲线法优化贵州某磷块岩浮选工艺研究

对贵州某沉积钙质磷块岩进行了浮选工艺研究。采用H₂SO₄为氟磷灰石抑制剂、BW-1为白云石捕收剂,进行了浮选单因素试验; 在此基础上进行了正交试验,并采用响应面曲线法进行了浮选条件优化。确定了最佳浮选条件为: 磨矿细度-0.074 mm粒级占60%、H₂SO₄用量13.20 kg/t和BW-1用量400 g/t。采用一段反浮选试验流程,可得到精矿品位30.94%、回收率92.45%的磷精矿。研究结果表明,磨矿细度与H₂SO₄用量的交互作用对精矿品位影响显著,H₂SO₄用量和BW-1用量的交互作用对精矿回收率影响显著。     

Effect of ultrasound on the true flotation of lignite and its entrainment behavior

In this study, the ultrasound was fixed in the pulp zone of flotation cell and its effect on the true flotation of lignite was analyzed. Flotation results indicated that the simultaneous ultrasound treatment increased the concentrate yield and decreased the concentrate ash content. Screening analysis of flotation products revealed that the ultrasound could crush coarse coal to fine coal and scanning electron microscopy (SEM) tests indicated that the ultrasound could reduce the coverage of high-ash coal fines on the coarse particle surface. Thus, the flotation recovery of coarse lignite particle was increased. In addition, the true flotation and entrainment of ?0.074 mm fine particles were studied by the sink-float test and the method of Trahar. It was found the ultrasound significantly enhanced the true flotation of fine particles and improved the overall water recovery in lignite flotation.     

改性淀粉抑制赤铁矿反浮选石英的作用机理研究

通过矿物浮选试验、动电位测定以及吸附量测试,考察了4种淀粉抑制剂对赤铁矿和石英浮选性能的影响,并探讨了其作用机理。在碱性条件下,改性淀粉抑制剂对赤铁矿抑制效果明显,且以改性玉米淀粉效果最佳,改性磷酸酯淀粉、改性羧甲基淀粉的抑制效果次之,而普通淀粉抑制作用一般。同时4种淀粉抑制剂对主要脉石矿物石英的抑制效果均不明显。pH=10~12.5条件下,改性玉米淀粉因其羟基氧和裸露在赤铁矿表面的铁元素发生了化学键合,因而选择性抑制能力最佳。分子动力学模拟表明,改性玉米淀粉片段与赤铁矿作用更为紧密,验证了改性淀粉能更好地抑制赤铁矿。     

某贫磁赤铁矿石选矿工艺试验研究

为了使某矿山贫磁赤铁矿资源得到合理的开发利用，针对现开采部位矿石的性质和可选性问题，进行了工艺矿物学和可选性试验研究。试验结果表明：采用弱磁、强磁—阴离子反浮选工艺可得到精矿铁品位68.55%、精矿产率36.41%、金属回收率79.92%、尾矿品位9.86%的较好选别指标，说明矿石的可选性较好，为该矿石的合理开发利用提供了可靠的技术依据。     

Investigation of Copper Recovery from a New Copper Deposit (Nussir) in Northern Norway

ABSTRACT

Norway has seen an upsurge of interest in exploiting its mineral deposits during the last decade. One of the major areas of interest is a huge copper deposit, operated by Nussir ASA located in the Repparfjord tectonic window in the Caledonides of west Finnmark. Nussir ASA is evaluating the Nussir and Ulveryggen mineral resources that contain copper sulfides with a small amount of gold and silver bearing minerals. The performance of flotation operations is generally evaluated on the basis of degree of liberation of minerals or the surface interactions between the collector and mineral. Firstly, size-by-size mineralogical characterization of the flotation feed and cumulative final product using Zeiss automated mineralogy techniques (Mineralogic) revealed that mineral liberation heavily influenced the flotation behavior of the ore. Furthermore, in order to assess the role of pH, collector concentration and flotation time, bench scale flotation experiments were performed. The metallurgical results were maximum between pH 6 and 8 and at collector concentration 6 × 10^?5 M. A correlation is established using the zeta potential and Hallimond flotation tests to assess the role of operating parameters in flotation. The distinctive role of process mineralogy and flotation chemical influence for copper mineral flotation of Nussir ore is presented in this article.     

低碱度下高硫铅锌矿的无钙浮选分离工艺研究

为了解决高硫铅锌矿分离时石灰用量大的问题,结合工艺矿物学,对云南某高硫铅锌矿进行了选矿试验研究。试验结果表明,在低碱度的情况下(pH值=9)采用LY-2可以较好地抑制黄铁矿。闭路试验可获得铅精矿含铅61.13%,铅回收率88.40%,铅硫分离铅作业回收率91.75%,硫精矿含铅1.66%,含锌2.76%,铅回收率7.95%,锌回收率5.19%,实现了铅硫的高效分离,对该类矿山的开发提供新思路。     

某铜矿重介质产品提铁降硫选矿试验

某铜矿重介质产品铁品位56.24%，硫含量高达9.34%，95.72%的硫以磁黄铁矿的形式存在。为获得硫含量<2%的铁精矿，按磨矿—弱磁选—浮选原则流程对该矿石进行了选矿试验。试验结果表明，在最佳试验参数下，重介质产品经一段磨矿（-0.043 mm 85%）—1粗1精弱磁选—1粗2扫脱硫浮选流程处理，可获得产率45.23%、硫含量为1.52%、全铁品位66.50%的铁精矿，可作为后续钢铁冶炼原料的配矿使用，为此类重介质产品的利用提供技术参考。