CO2 Capture from IGCC by Low-Temperature Synthesis Gas Separation

Capture conditions for CO2 vary substantially between industrial point sources. Depending on CO2 fraction and pressure level, different capture technologies will be required for cost- and energy-efficient decarbonisation. For decarbonisation of shifted synthesis gas from coal gasification, several studies have identified low-temperature CO2 capture by condensation and phase separation as an energy- and cost-efficient option. In the present work, a process design is proposed for low-temperature CO2 capture from an Integrated Gasification Combined Cycle (IGCC) power plant. Steady-state simulations were carried out and the performance of the overall process, as well as major process components, were investigated. For the baseline capture unit layout, delivering high-pressure CO2 at 150 bar, the net specific power requirement was estimated to 273 kJe/kgCO2, and an 85% CO2 capture ratio was obtained. The impact of 12 different process parameters was studied in a sensitivity analysis, the results of which show that compressor and expander efficiencies, as well as synthesis gas separation temperature, have the highest impact on power requirements. Modifying the process to producing cold liquid CO2 for ship transport resulted in 16% increase in net power requirements and is well suited for capturing CO2 for ship transport.

Design of Boosted Multilevel DC-DC Converter for Solar Photovoltaic System

Integration of renewable energy sources to the grid-connected system has influenced scholarly research in recent times to evolve solutions for power electronic conversion. Particularly, solar photovoltaic (SPV), being a resource available throughout the year, demands needful research to meet the demand for industrial applications. To facilitate SPV, multilevel inverters (MLIs) and cascaded H-bridge inverters (CHBIs) are proposed in the literature to meet the power requirement. However, these circuits suffer from efficiency loss, economic aspects of DC sources usage, and switching losses. Hence, in this research, a new power converter topology is projected to improve the overall efficiency of SPV systems. Further, a three-level approach involving (i) SPV Panel-Temperature Reduction (SPV-PTR) Setup, (ii) Boost Multilevel Direct Current Link Converter (BMLDCLC), and (iii) use of effective snubber modules (SM) are effectively handled to promote the industry readiness of the proposed system. From a detailed system investigation, it is seen that the proposed arrangement has minimized the power loss to ensure better quality in output. Furthermore, the software-based results and hardware setup of the planned comprehensive converter have shown promising results in terms of (i) reduced voltage stress, (ii) reduced total harmonic distortion (THD) without filter component, and (iii) reduced power loss. It is observed that the experimental setup has reported a 12.9% of excess heat removal, 5% decrease in harmonics, and 33% switch reduction than the existing MLI schemes. In addition, the proposed setup is suggested to apply for industrial purposes indicate its efficacy to be a solution in real time.

High temperature fuel cells to reduce CO2 emission in the maritime sector

Recently the interest in the sustainability of the maritime sector has increased exponentially. The International Maritime Organization (IMO) set as objective the reduction of CO2 emissions by 2030 by a margin of 40% compared to 2008. Recent studies showed that, according to the ships and the emission mitigation method applied, only 15–25% of CO2 reduction is de facto needed. Fuel cells represent an answer to meet this regulation. We propose two different solutions: (i) produce with SOFCs instead of engines the minimum power necessary to cut 20% of the emissions, or (ii) reduce the engine power of about 10% balancing the power requirement using MCFCs with CO2 capture. Using Aspen Plus each solution was investigated. The analysis contemplated LNG steam reforming to produce the H2 necessary for cell operation and the separation and liquefaction of CO2. Two case studies were considered comparing existing passenger ships with engines working on HFO and on LNG respectively. Although both solutions showed potential for the reduction of CO2 emissions respecting the IMO regulations, the SOFC solution requires a major change in the design of the ship, while MCFCs are proposed as an urgent solution allowing ship retrofitting without demanding update.

SIMULATION OF DESIGN VARIABLES EFFECT ON PERFORMANCE OF A COMMON BEANS (Phaseolus vulgaris L) PORTABLE THRESHER

In Kenya, threshing of common beans is mainly by traditional method using sticks and animal tramping, which are slow, inefficient and tedious. Consequently, there is a need to develop portable threshers locally available in the market for small and medium-scale farmers. The objective of this study was to simulate design variables effect on the performance of a common beans portable thresher. Sizing of design variables and parameters was key in development of bean thresher. This could be achieved by costly experiments or use of prediction mathematical model equation. The later method was used by developing mathematical models from combination of Buckingham pi theorem and reference to other similar work in literature. The predicting equation for power requirement, grain losses, grain damages, efficiency and throughput capacity were developed and validated using experimental thresher from the same study. The results showed that there was a positive correlation with R2 of 0.9. Based on actual data and 10% absolute residual error interval, the prediction performance of the developed models were above 77%. The results noted that increase in cylinder peripheral speed of the pegs resulted into increase in power requirement, bean grains damages, threshing efficiency and throughput capacity. Also increase in effective cylinder diameter caused increase in threshing efficiency and grain damages.

Generic Analysis Framework for Modular Multilevel Converter HVDC with Multi-Infeed Line-Commutated Converter HVDC System

This paper proposes a generic analysis framework for a grid supporting modular multilevel converter (MMC)-high voltage DC (HVDC) in a multi-infeed of line commutated converter (LCC) and MMC (MILM) system. MMC-HVDC can support the grid by compensating for the exact reactive power consumptions within the MMC-HVDC system and the varying power system conditions in the MILM system. Maximum active/reactive power capability (MPQC) curve and PQ loading curve comparison process is introduced to properly design a grid supporting MMC-HVDC. While the MPQC curve presents the maximum PQ range of the MMC-HVDC system based on the submodule capacitance value and the modulation index, the PQ loading curve presents the reactive power requirement from the power system that MMC-HVDC needs to compensate. Finally, the comparison of these two curves yields the proper value of submodule capacitance and the modulation index for sufficiently supporting the MILM system. The proposed framework is validated with detailed PSCAD/EMTDC simulation; it demonstrated that it could be applied to various power system conditions.

Influence of soil moisture on energy requirement of rotary tilling

The rotary tiller with ‘L’ shaped blades was examined for torque, power and specific tilling energy requirements to attain optimum soil-machine operational parameters. The three levels of moisture content (11.4%, 12.8% and 14.6% (d.b)), three speed ratios of 20 (?1), 12 (?2) and 9 (?3) at different passes (first, second and third) with rotational speed of 262 rpm were selected for study. The observations indicated inverse relation between torque and power requirement to moisture content. The lowest value of torque of 16.54 N-m and 26.66 N-m was associated with sandy loam and clay loam soil under third pass and moisture content of 14.6 per cent. Similarly, the minimum power requirement of 0.452 kW and 0.699 kW was observed under analogous conditions of rotary tiller. The energy requirement was found to decrease with higher number of passes due to the breakdown of the hard pan and clod aggregate size. The specific tilling energy is strongly correlated with forward speed and less dependent on the number of the passes of rotary tilling.

DEVELOPMENT OF INTELLIGENT SELF-BALANCING E-BIKE USING MACHINE LEARNING

The self-driving autonomous cars is becoming an increasingly popular concept all around the world but the area of self-driving two wheelers is still under developed. For developing countries like India, two wheelers are affordable than cars for most of the population. The project aims at developing intelligent self-balancing bike using artificial intelligence because the major problem in developing an autonomous bike is in the area of balancing. Even though there are many working mechanisms available for self-balancing of bike, the implementation of AI will be an edge over others from the point of computational power requirement and the programming complexity incurred. A prototype of the bike was developed with reaction wheel mechanism for self-balancing. The mechanism was fully controlled by AI by preventing the need of explicit programming for balancing which was the earlier technique used in self-balancing bike. Reinforcement learning, a type of machine learning technique is adopted for this purpose. The policy gradient algorithm was used to make the bike learn by itself for balancing. Even though the AI algorithm worked well in the virtual environment (balancing a cart-pole) it fails in the real environment. (i.e. it fails to balance the bike). It is because of the noisy data from the sensor, which gives inaccurate information about the orientation of the bike. The noise in the data is due to the vibration of the body when the reaction wheel rotates. This could be solved if the AI is fed with accurate information about the orientation of the vehicle.

ENERGY EFFICIENCY BASED OPERATION OF COMPRESSED AIR SYSTEM ON SHIPS TO REDUCE FUEL CONSUMPTION AND CO2 EMISSION

Energy efficiency subject has been gaining importance in maritime sector. The compressed air is a valuable energy source in operational manner, by the reason of intrinsic lack of efficiency in pressurization process. Operational pressure and leakage rate are the major variables which affect operational efficiency of the system. This study aims to reveal potential energy saving for the compressed air system. To this end, several pressure ranges, 29-30 bars to 14-18 bars, and different leakage rates 2.4% to 45% are evaluated. After the data was obtained from ships, thermodynamic calculations had been carried out. Optimization of pressure saves 47.3% in daily power requirement, 58,2% in compressed air unit cost, 18.4 and 57.4 tons of reduction in fuel consumption and CO2 emissions in a year respectively. High leakage rates can cause 2.7 times more power and fuel consumption. Finally, operating load, as an important indicator of compressor, makes imperfections identifiable.

Microgrids dynamic stability interconnected through low voltage AC network

Renewable energy based microgrids have main challenges of maintaining its frequency-voltage characteristics and system becomes more complex when they are interconnected. These sources being intermittent in nature need to be supported by other resources like diesel/biogas such that at time of small variation in load or natural sources (wind/solar), power requirement is met through support provided by diesel/biogas-based system. Also, the controller should be fast enough to minimize the changes such that system reaches steady state. In this paper, renewable based rural microgrid consisting of wind, solar and biogas is modeled and interconnected through low voltage AC (LVAC) line. Also, one of the microgrid modeled is connected to the main grid as well as drawing power from the other microgrid. Control approach have been developed in such a way that whenever there is disturbance in the system due to increase/decrease in load or input to the renewable energy sources the biogas-based system of individual microgrid increases/decreases its generation to support the system requirement. No extra power is drawn either from the LVAC network or main grid as desired. modeling of system and its dynamic Study has been carried out in MATLAB/Simulink.

Critical Analysis of the Application of Fuzzy Logic in Renewable Energy Systems

This study describes the effectiveness of applying Fuzzy controller into the renewable energy storage system for better efficiency. Different small size power generators need to be initially started up in order to fulfil the demand of power at the rush hours. V2G (Vehicle to grid) technology is an interface of bidirectional electrical grid which allows electric vehicles to take energy from the mesh. The calculation for the power requirement of the battery is initiated for identifying the charging load. When it comes to power management for the electric vehicles (EVs), information technology plays a vital role for the V2G framework. The delivery of power request to the aggregate of EVs through the aggregator is done with the help of sending a signal from the RTO/ISO. The load is generated with the help of huge as well as continuously running units of power generation and gradable EVs. In V2G optimization, lowering the overall operational cost may be achieved by using wind power as well as using the grid.