Microwave processing of oil contaminated drill cuttings

Easily accessible oil reserves are currently decreasing, leading to an increase in more complex offshore deep-sea drilling programs, which require increasingly greater depths to be drilled. Such wells are commonly drilled using oil based muds, which leads to the production of drilled rock fragments, drill cuttings, which are contaminated with the base oil present in the mud. It is a legal requirement to reduce oil content to below 1 wt% in order to dispose of these drill cuttings in the North Sea and microwave processing is suggested as a feasible method of achieving the desired oil removal. However, there are currently gaps in our understanding of the mechanisms behind, and variables affecting, the microwave treatment of oil contaminated drill cuttings. The work described in this thesis seeks to address some of these gaps in knowledge. There were three main objectives for this thesis: (1) quantification, for the first time in the literature, of the main mechanisms driving oil and water removal during microwave processing of oil contaminated drill cuttings, (2) determination of key variables affecting performance during pilot scale continuous processing of oil contaminated drill cuttings and, for the first time, (3) treatment of drill cuttings with microwaves continuously at 896 MHz. Bench scale experiments carried out in a single mode applicator were used to quantify the mechanisms involved in oil and water removal from drill cuttings. It was found that both vaporisation and entrainment mechanisms play a role in oil and water removal. Vaporisation was the main mechanism of water and oil removal, and typically accounted for >80-90% of the water and oil removed. For oil removal, vaporisation of the oil phase accounted for 70-100% of the overall removal. The absolute amount of water entrained and vaporised was found to increase with increasing energy input and power density. However, as a percentage of the overall amount removed, entrainment was found to increase with increasing energy input. This was mainly due to higher heating rates at higher energy inputs, leading to pressurised, high velocity steam, which increased liquid carry-over (entrainment). Both the drill cuttings sample composition and applicator type were found to have an effect on the extent of entrainment/vaporisation. Samples consisting of a higher overall liquid content, tended to have a greater amount of surface liquid content. This led to a greater potential of carry over when steam generated internally left the sample. Increasing the power again led an increase in entrainment in this case. Different applicators were found to impact the electric field strength and power density within the water phase of the sample. Oil removal in multimode applicators progressed mainly through vaporisation (steam distillation) until the water content was sufficiently low to generate steam at a velocity high enough to entrain liquid droplets. When treatment was changed to single mode operation, entrainment occurred at an earlier stage, probably due to higher electric field strengths and power densities. It was also noted that the vaporisation mechanism of oil was more efficient at higher field strengths and powers, which could again be attributed to superheating and higher velocity steam, which enabled better mixing and heat transfer. Experiments were also run to determine the main variables affecting the performance of continuous processing of cuttings. Overall continuous processing showed a substantial improvement in the energy required, 150 kWh/t vs. >250 kWh/t, to reduce the oil content of a drill cuttings sample to 1 wt%. It was found that the initial water and oil content of the sample, as well as the sample particle size distribution, had the greatest effect on the efficiency of continuous processing. The effect of initial water and oil content on residual oil content was investigated methodically for the first time for continuous microwave processing of oil contaminated drill cuttings. An increase in initial oil content was found to have a significant impact on the energy input required to treat the sample to 1 wt% oil content. As the oil content increased, the energy input required increased exponentially, mainly as a result of the change in the physical structure of the sample. An increase in the water content led to an increase in energy input without any additional benefit to oil removal. However, as the water content was increased it was noticed that the theoretical energy input required to heat the entire sample approached the actual value measured for the energy input. This occurs as a result of the increasingly greater bulk dielectric properties of the sample as a result of higher levels of water content, which in turn leads to a higher efficiency in the conversion of microwave energy to heat in the sample. The effect of particle size on oil content distribution and removal was investigated. Oil content was found to be substantially higher in particles of size 80%, consisted of particles >1.0 mm, this improved removal is diluted by the performance of the coarser particles. The improved removal in finer particles is likely to be due to larger surface area, reduced path length within the particles and potentially higher electric field strength. Finally, samples processed continuously using a continuous microwave setup at 896 MHz showed improvements over both continuous microwave treatment at 2.45 GHz and bench scale setups. Increasing the f10wrate of the system at 896 MHz was also found to improve oil removal efficiency, which can be explained by the higher power requirements that would be required to maintain the energy inputs observed at the lower flowrate. Increasing the power leads to improved heating rates and thus increased removal rates through entrainment and vaporisation

Impacto de los incendios forestales en la regulación de las inundaciones y la depuración del agua

Wildfires are global phenomena with positive and negative impacts on ecosystems. They are a natural ecosystem element that shaped several biomes. However, for some time, they may disturb the ecosystems, reducing their capacity to supply several services. The objective of this article is to resume the impacts of wildfires on flood regulation and water purification and discuss the use of some restoration measures to mitigate the wildfire impacts. Wildfires, especially in the immediate period after, reduce the ecosystem’s capacity to regulate floods and purify water due to vegetation removal and ash that can degrade water quality. The magnitude of the impacts depends essentially on wildfire severity and post-wildfire precipitation intensity. Restoration measures must be applied, especially after high-severity wildfires and if the recurrence is high. In the context of climate change, the interval between fires is expected to be shorter, and the severity will be high. Therefore, restoration measures may be more needed.Los incendios forestales son un fenómeno global con repercusiones positivas y negativas en los ecosistemas. Estos son un elemento natural de los ecosistemas que dio forma a diversos biomas. Sin embargo, durante algún tiempo, pueden perturbar los ecosistemas, reduciendo su capacidad para suministrar diversos servicios. El objetivo de este artículo es resumir los impactos de los incendios forestales en la regulación de las inundaciones y la depuración del agua y discutir el uso de algunas medidas de restauración para mitigar los impactos de los incendios forestales. Los incendios forestales, especialmente en el periodo inmediatamente posterior al evento, reducen la capacidad del ecosistema para regular las inundaciones y depurar el agua debido a la eliminación de vegetación y cenizas que pueden degradar la calidad de ese agua. La magnitud de los impactos depende esencialmente de la severidad del incendio forestal y de la intensidad de las precipitaciones posteriores al mismo. Deben aplicarse medidas de restauración, especialmente después de incendios forestales de gran severidad y si la recurrencia es elevada. En el contexto del cambio climático, se espera que el intervalo entre incendios sea más corto y que la severidad sea mayor. Por lo tanto, las medidas de restauración pueden ser más necesarias

Digital Literacy and Propaganda

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Acesso, equidade e coesão social: avaliação de estratégias intersetoriais para a população em situação de rua

Objective To understand and evaluate the work of intersectoral assistance on the insertion and the flow of people in situation of street with severe mental illness in public services of Mental Health. Method A case study developed from ten visits to a night shelter between March and April 2012. For data collection, the participant observation and semi-structured interviews were carried out with four sheltered individuals, as well as non-directive group interviews with five technicians of the social-assistance services. Results Were analyzed using Content Analysis and developing a Logic Model validated with the professionals involved. Conclusion The social assistance services are the main entry of this clientele in the public network of assistance services, and the Mental Health services have difficulty in responding to the specificities of the same clientele and in establishing intersectoral work.
Objetivo Compreender e avaliar o trabalho de assistência intersetorial sobre a inserção e o fluxo de pessoas em situação de rua, com transtorno mental grave, nos serviços públicos de Saúde Mental. Método Estudo de caso, desenvolvido a partir de 10 visitas a um albergue, entre março e abril de 2012. Para a coleta de dados foi realizada a observação participante e entrevistas semiestruturadas com quatro albergados, além de entrevistas não diretivas em grupo, com cinco técnicos dos serviços socioassistenciais. Resultados Foram analisados por meio da Análise de Conteúdo e da elaboração de Modelo Lógico, e validados junto aos profissionais envolvidos. Conclusão Os serviços socioassistenciais são a principal entrada dessa clientela à rede pública de assistência, e que os serviços de Saúde Mental apresentam dificuldades em responder às especificidades dessa mesma clientela e estabelecer trabalho intersetorial.
Objetivo Comprender y evaluar el trabajo de asistencia intersectorial acerca de la inserción y el flujo de personas en situación de calle, con trastorno mental severo, en los servicios públicos de Salud Mental. Método Estudio de caso, desarrollado a partir de 10 visitas a un albergue, entre marzo y abril de 2012. Para la recolección de datos fue realizada la observación participante y entrevistas semiestructuradas con cuatro albergados, además de entrevistas no directivas en grupo, con cinco técnicos de los servicios socioasistenciales. Resultados Fueron validados mediante el Análisis de Contenido y la confección del Modelo Lógico, y validados junto a los profesionales involucrados. Conclusión Los servicios socioasistenciales son la principal forma de ingreso de esa clientela a la red pública de asistencia, y que los servicios de Salud Mental presentan dificultades de responder a las especificidades de dicha clientela y establecer trabajo intersectorial.Universidade de São Paulo Faculty of MedicineUniversidade Federal de São Paulo (UNIFESP)UNIFESPSciEL