Increase of energy recovery from sewage sludge

The use of the pyrolysis process to obtain valuable products from biomass is amongst the technologies being investigated as a source for renewable energy. The pyrolysis process yields products such as biochar, bio-oil and non condensable gases. The main objective of this project is to increase energy recovery from sewage sludge by utilising the intermediate pyrolysis process. The intermediate pyrolysis has a residence time ranging from 5 to 10 minutes. The main product yields from sewage sludge pyrolysis are 50 wt% biochar, 40 wt% bio-oil and 10 wt% non condensable gases. The project was carried out on a pilot plant scale reactor with a load capacity of 20 kg/h. This enabled a high yield of biochar and bio-oil. The characterisation of the products indicated that the organic phase of the bio-oil had good fuel properties such as having high energy content of 39 MJ/kg, low acid number of 21.5, high flash point of 150 and viscosity of 35 cSt. An increase in pyrolysis experiments enabled large quantities of pyrolysis oil production. Co-pyrolysis of sewage sludge was carried out on laboratory scale with mixed wood, rapeseed and straw. It found that there was an increase in bio-oil quantity with rapeseed while co-pyrolysis with wood helped to mask the smell of the sludge pyrolysis oil. Engine test were successfully carried out in an old Lister engine with pyrolysis oil fractions of 30% and 50% blended with biodiesel. This indicates that these pyrolysis oil fractions can be used in similar engine types without any problems however long term effects in ordinary engines are unknown. An economic evaluation was carried out about the implementation of the intermediate pyrolysis process for electricity production in a CHP using the pyrolysis oil. The prices of electricity per kWh were found to be very high.

Element characteristic tolerance for semi-batch fixed bed biomass pyrolysis

Biomass pyrolysis to bio-oil is one of the promising sustainable fuels. In this work, relation between biomass feedstock element characteristic and crude bio-oil production yield and lower heating value was explored. The element characteristics considered in this study include moisture, ash, fix carbon, volatile matter, C, H, N, O, S, cellulose, hemicellulose, and lignin content. A semi-batch fixed bed reactor was used for biomass pyrolysis with heating rate of 30 °C/min from room temperature to 600 °C and the reactor was held at 600 °C for 1 h before cooling down. Constant nitrogen flow (1bar) was provided for anaerobic condition. Sago and Napier glass were used in the study to create different element characteristic of feedstock by altering mixing ratio. Comparison between each element characteristic to crude bio-oil yield and low heating value was conducted. The result suggested potential key element characteristic for pyrolysis and provide a platform to access the feedstock element acceptance range.

Comprehensive characterization of Napier grass as a feedstock for thermochemical conversion

Study on Napier grass leaf (NGL), stem (NGS) and leaf and stem (NGT) was carried out. Proximate, ultimate and structural analyses were evaluated. Functional groups and crystalline components in the biomass were examined. Pyrolysis study was conducted in a thermogravimetric analyzer under nitrogen atmosphere of 20 mL/min at constant heating rate of 10 K/min. The results reveal that Napier grass biomass has high volatile matter, higher heating value, high carbon content and lower ash, nitrogen and sulfur contents. Structural analysis shows that the biomass has considerable cellulose and lignin contents which are good candidates for good quality bio-oil production. From the pyrolysis study, degradation of extractives, hemicellulose, cellulose and lignin occurred at temperature around 478, 543, 600 and above 600 K, respectively. Kinetics of the process was evaluated using reaction order model. New equations that described the process were developed using the kinetic parameters and data compared with experimental data. The results of the models fit well to the experimental data. The proposed models may be a reliable means for describing thermal decomposition of lignocellulosic biomass under nitrogen atmosphere at constant heating rate.

The thermal performance of the polysaccharides extracted from hardwood:cellulose and hemicellulose

The pyrolytic behaviour of individual component in biomass needs to be understood to gain insight into the mechanism of biomass pyrolysis. A comparative study on the pyrolysis of cellulose (hexose-based polysaccharides) and hemicallulose (pentose-based polysaccharides) is performed by two sets of experiments including TG analysis and Py-GC-MS/FTIR. The samples of these two polysaccharide components are thermally decomposed in TGA at the heating rate of 5 and 60 K/min to demonstrate the different characteristics of mass loss stage(s) between them. The yield of pyrolytic products is examined by a fluidized-bed fast pyrolysis unit. The experiment confirms that cellulose mainly contributes to bio-oil production (reaching the maximum of 72% at 580 °C), while hemicellulose works as an important precursor for the char production (∼25%). The compounds in the gaseous mixture (CO and CO2) and bio-oil (levoglucosan, furfural, aldehyde, acetone and acetic acid) are further characterized by GC-MS for cellulose and GC-FTIR for hemicellulose, and their formations are investigated thoroughly. © 2010 Elsevier Ltd. All rights reserved.

Estudo paramétrico da injeção de polímeros em reservatórios de petróleo

Developing an efficient methodology for oil recovery is extremely important . Within the range of enh anced oil recovery, known as EOR, the injection of polymer solutions becomes effective in controlling the mobility of displacing fluid . This method consists of adding polymers to the injection water to increase its viscosity, so that more water diffuses in to the porous medium and increasing the sweep efficiency in the reservoir. This work is studied by numerical simulation , application of the injection polymer solution in a homogeneous reservoir , semisynthetic with similar characteristics to the reservoirs of the Brazilian Northeast , numerical simulations were performed using thermal simulator STARS from CMG (Computer Modelling Group ). The study aimed to analyze the influence of some parameters on the behavior of reservoir oil production, with the response to cumulative production. Simulations were performed to analyze the influence of water injection, polymer solution and alternating injection of water banks and polymer solution, comparing the results for each simulated condition. The primary outcomes were: oil viscosity, percentage of injected polymer, polymer viscosity and flow rate of water injection. The evaluation of the influence of variables consisted of a complete experimental design followed a Pareto analysis for the purpose of pointing out which va riables would be most influential on the response represented b y the cumulative oil production . It was found that all variables significantly influenced the recovery of oil and the injection of polymer solution on an ongoing basis is more efficient for the cumulative production compared to oil recovery by continuous water injection. The primary recovery show ed low levels of oil production , water injection significantly improves the pro duction of oil in the reservoir , but the injection of polymer solution em erges as a new methodology to increase the production of oil, increasing the life of the well and possible reduction of water produced.

Incrustação em poço produtor de petróleo e gás natural: um estudo de caso

Water and gas is a common by - product of the oil production process. Production may be compromised by the precipitation of inorganic salts in both the reservoir and producing well, through scale formation. This precipitation is likely the cause of the formation damage. High temperatures and h igh pressures (HTHP) may favor the precipitation of insoluble salts. The most common types of scale in oil fields are calcium carbonate and calcium sulphate, strontium and barium sulphate. New types of scale formation have attracted special attention such as zinc sulphide and lead. This precipitation may occur in the pores of reservoir rocks, in the production string and in equipment, causing obstructions and consequent production losses. In this study, the influence of well depth on incrustation compositio n was investigated to design removal treatments and assess the behavior of these deposits along the string, through the analysis of pressure and temperature. Scale residues were recovered from the inside of the production string of an oil and gas well duri ng the string removal operation. A total of 10 samples from different depths (15.4 m to 4061.5 m) were obtained. Initially a dissolution test was conducted in weak acid, similar to that used in removal operations with this type of scale formation. Majority composition was defined and confirmed by dissolution tests using X - Ray Fluorescence Spectroscopy (XRF), X - Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) techniques. Residues with distinct characteristics were observed in different proportion s, showing a tendency toward increased and/or decreased mass with depth. In the samples closest to the surface, typical sandstone residues were found, with calcium (45% Ca) as the metal of highest concentration. The obtained results indicate correlations o f the scale types studied with the depth and, consequently, with the thermodynamic conditions of pressure and temperature.

Alterações morfofisiológicas e moleculares em resposta a estresses abióticos em mamona (Ricinus communis L.)

The use of fossil fuels has been considered one of reason for the increase of pollution in the atmosphere and it may be related to the climate changes. Then, the research of the new sources of fuels will be important. Considering this, the use of biodiesel has been considered not as bad as petrol. The castor bean (Ricinus communis L.) is an important oilseed, which belongs to Euphorbiaceae family, and the oil found in the seed has important characteristics for biodiesel. This plant is considered as “rustic” as it does not need so much water for its development and oil production. Due to this, this plant has been considered to be ideal in semi-arid regions, such as the Northeast of Brazil. The aim of his study is to better understand the responses to abiotic stresses (drought and salinity) from castor bean plants using morphological, physiological and molecular tools. In order to do this, the castor bean plants were subjected to salt stress (50, 100, 150 and 200 mM NaCl) in a controlled environment and drought stress (5, 10, 15 days and 10 days cyclic). After these treatments, these plants were subjected to different analyzes: a) the expansion and retention of water from leaves; b) anatomy using leaves and roots. Based on these results, we found that castor suffered decrease in leaf area with increase drought stress, however restricted water loss, probably by accumulation of compatible solutes in the leaves. The anatomy data showed modifications in the vascular system. These modifications observed suggested that castor bean plant may be resistant to stress as it was verified in 5 days of drought as well as in 100 mM NaCl. In both conditions, these plants were fine. Probably these plants keep some solutes in the cell and then maintain the cell tugor. The data obtained in this study gave a better idea how castor bean plant responds to abiotic stress conditions - drought and salt stress

Mapeamento da isoterma de Curie na Bacia do Parnaíba estimada através da profundidade da base das fontes magnéticas

Located on the western edge of the Brazilian northeast, the Parnaíba Basin is an intra cratonic basin with oil production. This study aims at understanding its genesis and evolution, using aeromagnetic and gravity data. We used the spectral analysis of aeromagnetic data to map the depth to the bottom of the magnetic sources in order to assimilate this depth with the depth of the Curie isotherm, and infer the geothermal gradient. Using the spectral analysis technique, we succeeded in mapping the surface of the depth to the bottom of magnetic sources (SBFM), which marks the depth that occur magnetization. In the Parnaíba Basin the SBFM presented depths around -20,5 and -28,5 , which was consistent with an inversion of the same dataset using the technique of Magnetization Vector Inversion (MVI). Furthermore, SBFM topography correlates well with Moho depth, which was estimated from satellite gravimetric data from the GOCE mission (Gravity Field and Steady-State Ocean Circulation Explorer). Assuming that SBFM coincides with the Curie isotherm of magnetite (ICM), defined as the surface at which magnetite ( ) looses its ferromagnetic properties, it was possible to estimate the geothermal gradient. The geothermal gradient in the basin showed values between 19.2 and 26.5 , allowing to estimate the heat flow for the Parnaíba basin after assuming a conductivity of 2.69 . The resulting heat flow values ranged between 51.6 and 71.3 , which is consistent with values found in other works throughout the South American continent. Lithospheric thickness using an empirical relationship, finding values between -65.8 and -89.2 . We propose that thermal structure of Parnaíba basin is influenced by a deep thermal anomaly. This anomaly has heated the lithosphere beneath the basin and has resulted in relatively thin values for the lithospheric thickness and relatively high surface heat flow values. The origin of the anomaly is not clear, but the correlation between Curie depth and Moho topography, suggests that tectonic extension processes could have played a role.

Recuperação avançada de óleos pesados em poços fraturados utilizando aquecimento eletromagnético indutivo

The success achieved by thermal methods of recovery, in heavy oils, prompted the emergence of studies on the use of electromagnetic waves as heat generating sources in oil reservoirs. Thus, this generation is achieved by three types of different processes according to the frequency range used. They are: the electromagnetic induction heating, the resistive and the dielectric, also known as radiation. This study was based on computer simulations in oil reservoirs with characteristics similar to those found in the sedimentary basins of the Brazilian Northeast. All cases studied were simulated using the software STARS, CMG (Computer Group, version 2012.10 Modeling). Some simulations took into account the inclusion of electrically sensitive particles in certain sectors of the reservoir model studied by fracturing. The purpose of this work is the use of the electromagnetic induction heating as a recovery method of heavy oil, to check the influence of these aforementioned particles on the reservoir model used. Comparative analyses were made involving electromagnetic induction heating, the operation of hydraulic fracturing and the injection of water to the different situations of the reservoir model studied. It was found that fracturing the injection well in order that the electromagnetic heating occurs in the same well where there is water injection, there was a considerable increase in the recovery factor and in the cumulative oil production in relation to the models in which hydraulic fracturing occurred in the production well and water injection in the injection well. This is due to the generation of steam in situ in the reservoir.

Modelagem matemática e experimental da perda de injetividade em poços canhoneados

Water injection in oil reservoirs is a recovery technique widely used for oil recovery. However, the injected water contains suspended particles that can be trapped, causing formation damage and injectivity decline. In such cases, it is necessary to stimulate the damaged formation looking forward to restore the injectivity of the injection wells. Injectivity decline causes a major negative impact to the economy of oil production, which is why, it is important to foresee the injectivity behavior for a good waterflooding management project. Mathematical models for injectivity losses allow studying the effect of the injected water quality, also the well and formation characteristics. Therefore, a mathematical model of injectivity losses for perforated injection wells was developed. The scientific novelty of this work relates to the modeling and prediction of injectivity decline in perforated injection wells, considering deep filtration and the formation of external cake in spheroidal perforations. The classic modeling for deep filtration was rewritten using spheroidal coordinates. The solution to the concentration of suspended particles was obtained analytically and the concentration of the retained particles, which cause formation damage, was solved numerically. The acquisition of the solution to impedance assumed a constant injection rate and the modified Darcy´s Law, defined as being the inverse of the normalized injectivity by the inverse of the initial injectivity. Finally, classic linear flow injectivity tests were performed within Berea sandstone samples, and within perforated samples. The parameters of the model, filtration and formation damage coefficients, obtained from the data, were used to verify the proposed modeling. The simulations showed a good fit to the experimental data, it was observed that the ratio between the particle size and pore has a large influence on the behavior of injectivity decline.

An application of evolutionary algorithms for WAG optimisation in the Norne Field

Water-alternating-gas (WAG) is an enhanced oil recovery method combining the improved macroscopic sweep of water flooding with the improved microscopic displacement of gas injection. The optimal design of the WAG parameters is usually based on numerical reservoir simulation via trial and error, limited by the reservoir engineer’s availability. Employing optimisation techniques can guide the simulation runs and reduce the number of function evaluations. In this study, robust evolutionary algorithms are utilized to optimise hydrocarbon WAG performance in the E-segment of the Norne field. The first objective function is selected to be the net present value (NPV) and two global semi-random search strategies, a genetic algorithm (GA) and particle swarm optimisation (PSO) are tested on different case studies with different numbers of controlling variables which are sampled from the set of water and gas injection rates, bottom-hole pressures of the oil production wells, cycle ratio, cycle time, the composition of the injected hydrocarbon gas (miscible/immiscible WAG) and the total WAG period. In progressive experiments, the number of decision-making variables is increased, increasing the problem complexity while potentially improving the efficacy of the WAG process. The second objective function is selected to be the incremental recovery factor (IRF) within a fixed total WAG simulation time and it is optimised using the same optimisation algorithms. The results from the two optimisation techniques are analyzed and their performance, convergence speed and the quality of the optimal solutions found by the algorithms in multiple trials are compared for each experiment. The distinctions between the optimal WAG parameters resulting from NPV and oil recovery optimisation are also examined. This is the first known work optimising over this complete set of WAG variables. The first use of PSO to optimise a WAG project at the field scale is also illustrated. Compared to the reference cases, the best overall values of the objective functions found by GA and PSO were 13.8% and 14.2% higher, respectively, if NPV is optimised over all the above variables, and 14.2% and 16.2% higher, respectively, if IRF is optimised.

SISAL - Um sistema supervisório para elevação artificial de petróleo

MEDEIROS, Adelardo A. D. et al. SISAL - Um Sistema Supervisório para Elevação Artificial de Petróleo. In: Rio Oil and Gas Expo Conference, 2006, Rio de Janeiro, RJ. Anais... Rio de Janeiro, 2006.

Achieving forms of sustainable and competitive tourism in coastal areas: the case of Baixo Vouga

Tourism has become the world’s largest industry, and has overcome economic sectors such as oil production and car manufacturing. It is foreseen that tourism will continue to expand in the future and will spread all around the world. In Europe, the tourism sector is made of 440 million international arrivals that are responsible for accounting about 10% of European GDP and generating 20 million jobs. Coastal destinations are major tourist destinations. This is due to their physical attractiveness, beautiful landscapes, and fine open space for leisure activities. Nevertheless, sun-sea-sand tourism depends very much on the environment. In this way, coastal destination ought to be properly planned so they do not exceed the limits of acceptable change (LAC) of the ecosystems, and keep their attractiveness. Being an economic activity, it is essential that coastal tourism is competitive, and show capacity to attracting new and enlarged markets. Coastal destinations should diversify its products and services, smooth seasonality and become more competitive. Diversification should create more growth and employment, and also reduce environmental, economic and social impact caused by the concentration of tourism activity in a few months of the year and the use of only the beach resource. This paper aims at analyzing the application of the competitiveness concept to tourism in coastal areas (Ria de Aveiro region, Central Portugal), and draws attention to the principle of environmental, economical and social sustainability.

SISAL - Um sistema supervisório para elevação artificial de petróleo

MEDEIROS, Adelardo A. D. et al. SISAL - Um Sistema Supervisório para Elevação Artificial de Petróleo. In: Rio Oil and Gas Expo Conference, 2006, Rio de Janeiro, RJ. Anais... Rio de Janeiro, 2006.

Estudo experimental do escoamento bifásico líquido gás em golfadas com leve mudança de direção

Gas-liquid two-phase flow is very common in industrial applications, especially in the oil and gas, chemical, and nuclear industries. As operating conditions change such as the flow rates of the phases, the pipe diameter and physical properties of the fluids, different configurations called flow patterns take place. In the case of oil production, the most frequent pattern found is slug flow, in which continuous liquid plugs (liquid slugs) and gas-dominated regions (elongated bubbles) alternate. Offshore scenarios where the pipe lies onto the seabed with slight changes of direction are extremely common. With those scenarios and issues in mind, this work presents an experimental study of two-phase gas-liquid slug flows in a duct with a slight change of direction, represented by a horizontal section followed by a downward sloping pipe stretch. The experiments were carried out at NUEM (Núcleo de Escoamentos Multifásicos UTFPR). The flow initiated and developed under controlled conditions and their characteristic parameters were measured with resistive sensors installed at four pipe sections. Two high-speed cameras were also used. With the measured results, it was evaluated the influence of a slight direction change on the slug flow structures and on the transition between slug flow and stratified flow in the downward section.