Solids Deposition from Paraffinic Mixtures: Investigation of 'Cold Flow' in Pipelines

石蜡混合物的固体沉积：管道中“冷流”的研究

• 批准号: RGPIN-2015-06498
• 负责人: Mehrotra, Anil
• 金额: $ 2.55万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=614184
• 关键词: Solids; Deposition; Paraffinic; Mixtures; Investigation

Most energy consumption forecasts suggest a continued growth in the worldwide petroleum demand. However, new crude oil reservoirs are deep, located offshore and contain heavy oils, with complex and costly infrastructure and operations. One serious challenge with deep-water petroleum production is the solids or wax deposition, which is known to cause plugging of pipelines and process equipment, requiring hundreds of millions of dollars annually for its control and remediation. Pipelines are known to have been abandoned because of becoming plugged with wax deposit. Wax deposition is a complex process, involving liquid-to-solid phase transformation of paraffins, which is influenced by cooling or crystallization rates, shear stress, the rate of heat transfer, and the oil composition.      The long-term objective of this research program is to develop simulation models and a novel software for solids deposition during pipeline flow and processing of 'waxy' (paraffinic) crude oils. The heat-transfer based approach developed in this research program is unique. Building on recent innovative accomplishments, the proposed research will focus on developing the 'cold flow' technology, which offers the benefit of much reduced levels of solids deposition. In the 'cold flow' regime, however, the fluid is actually a two-phase solid-liquid suspension created by the precipitated wax crystals, which would be expected to cause increased pressure drop across the pipeline.      A number of experimental and theoretical activities are proposed that involve phase transformation, solids deposition and thermophysical and transport properties of systems comprising heavy hydrocarbons. The research will involve experimentation, statistical analysis, and model development. Over the next 5 years, NSERC DG will be used to provide training to at least 10 HQPs (2 PhD, 3 MSc and 5 BSc students).      The research methodology involves experiments with defined mixtures to provide improved understanding of the basic processes, which will aid in the validation of new mathematical models. A rigorous heat-transfer based solids deposition model will be developed for simulating both laminar and turbulent flow under a wide range of operating conditions as well as for pipeline start-up and shutdown. The model development research will be augmented by experimental and theoretical studies, including solid deposition in bench-scale flow loop and cold finger apparatus (operated at temperatures below the wax appearance temperature), phase transformation, rheological behavior of the deposit, alternate mechanisms for deposit aging and sloughing phenomena, deposit thermal conductivity, etc. The developed software, incorporating validated mathematical models, will be used by the flow assurance groups of petroleum companies for tackling major challenges associated with solids deposition in a sustainable and cost-effective manner.

大多数能源消费预测表明，全球石油需求将继续增长。然而，新的原油储藏很深，位于近海，含有重油，基础设施和作业复杂而昂贵。深水石油生产的一个严重挑战是固体或蜡沉积，已知这会导致管道和工艺设备堵塞，每年需要数亿美元用于控制和补救。众所周知，管道因被蜡存款堵塞而被废弃。蜡沉积是一个复杂的过程，涉及链烷烃的液-固相转化，其受冷却或结晶速率、剪切应力、传热速率和油组成的影响。 这项研究计划的长期目标是开发模拟模型和一个新的软件，固体沉积在管道流动和加工的“含蜡”（石蜡）原油。在这项研究计划中开发的基于传热的方法是独一无二的。基于最近的创新成果，拟议的研究将集中在开发“冷流”技术，该技术提供了大大降低固体沉积水平的好处。然而，在“冷流”状态下，流体实际上是由沉淀的蜡晶体产生的两相固液悬浮液，这将预期导致穿过管道的压降增加。 提出了一些实验和理论活动，涉及相变，固体沉积和热物理和运输性质的系统，包括重烃。研究将涉及实验，统计分析和模型开发。在未来5年内，NSERC DG将用于为至少10名HQP（2名博士，3名硕士和5名理学士学生）提供培训。 研究方法包括使用定义的混合物进行实验，以提供对基本过程的更好理解，这将有助于验证新的数学模型。将开发一个严格的基于传热的固体沉积模型，用于模拟各种操作条件下的层流和湍流以及管道启动和关闭。模型开发研究将通过实验和理论研究得到加强，包括实验室规模流动回路和冷指装置中的固体沉积（在低于蜡出现温度的温度下操作）、相变、存款的流变行为、存款老化和脱落现象的交替机制、存款热导率等。所开发的软件，结合经验证的数学模型，将被石油公司的流动保障集团用于以可持续和具有成本效益的方式应对与固体沉积相关的重大挑战。