Kuntal Jana

Techno-economic evaluation of a polygeneration using agricultural residue - a case study for an Indian district.

Presently, most of world electricity and other energy services are catered by fossil fuel resources. This is unsustainable in the long run both with respect to energy security and climate change problems. Fuel switching, specifically using biomass may partially address this problem. Polygeneration is an efficient way of delivering multiple utility outputs with one or more inputs. Decentralized small or large scale polygeneration using alternative fuels may be a future sustainable solution. In this paper, a techno-economic evaluation of a polygeneration with four utility outputs and rice straw as input has been reported. Results of the simulation and real-life data as inputs are used for the techno-economic analysis. The analysis is specific for a district in the state of West Bengal of India. Results show that such a plant has strong potential to qualify in techno-economic performance in addition to higher efficiency and lower CO2 emission.

Environmental impact of biomass based polygeneration - A case study through life cycle assessment.

Multi-generation or polygeneration is considered to be a potential sustainable energy solution. To assess environmental sustainability of multi-generation, life cycle assessment (LCA) is a useful tool. In this paper, environmental impact of polygeneration using an agro waste (rice straw) is assessed by LCA. Then it is compared with stand alone conventional plants with same utility outputs. Power, ethanol, heating and cooling are utility outputs of the polygeneration plant. System boundary for this polygeneration is defined for surplus biomass only. Exergy based allocation method is used for this analysis. Results of LCA are shown through both mid-point and end-point indicators. Results indicate that polygeneration with surplus rice straw is more environment-friendly than conventional stand-alone generation of same utilities.

Polygeneration performance assessments: multi-dimensional viewpoint

Performance metrics of a system with single input and single output is straight forward and is generally termed as ‘efficiency’. However, for systems with multiple outputs, defined performance metrics has to include effects of all outputs on a rational basis. For systems with both multiple inputs and outputs such definition is even more complicated. Polygeneration is the integration of multiple utility outputs with one or more inputs for better performance. The better performance may again be assessed from different aspects, e.g., thermodynamic, economic, social, etc. Performance metrics of polygeneration is not unique. It depends on type of systems as well as objective of evaluation of it. In this paper, several possible performance parameters for polygeneration are discussed. Evaluation of performance is also tested with multi-dimensional viewpoints. Simulation results of two polygeneration schemes are used to show case studies for these defined performance parameters. Relative performance of polygeneration schemes with different fuel inputs is presented to show the performance variation of these schemes with multi-dimensional viewpoints.

Thermo-Chemical Ethanol Production from Agricultural Waste Through Polygeneration: Performance Assessment Through a Case Study

Substitution of fossil fuels by biofuels over a planned period is an imperative need to meet the energy demand in future with minimum possible environmental impact. Biofuels from food stuff may lead to conflict between energy and food security. However, producing biofuel (say, ethanol) from agricultural waste (say, rice straw) in thermo-chemical process may be a sustainable option through recycling of waste. But energy requirement for this process is significantly higher and independent production of ethanol may not be economically feasible. However, suitable integration of this ethanol production through an efficiently integrated multi-utility system called polygeneration may be economically feasible with low impact on the environment. This has been explored through a case study with thermodynamic, economic and environmental performance assessment. Results show sustainability of such a process with acceptable performance from multidimensional viewpoints.

Utilizing waste heat of the flue gas for post-combustion CO2 capture—A comparative study for different process layouts

ABSTRACT The inlet flue gas entering the absorber column must be ~40°C and hence needs cooling. In this article, it is proposed that waste heat be recovered from the flue gas using a condensing heat exchanger. This recovered heat is utilized as partial supplement to subsequent heating in stripper during CO2 capture. System layouts—one for base case and two others—have been conceptualized. ASPEN Plus® simulation results for the other two layouts are discussed for energy savings with respect to the base case. Results show that, for the other two layouts, reboiler heat duty decreases though carbon capture efficiency also decreases.

A CCGT Based Polygeneration Using Rice Straw: Simulation by Aspen Plus®

Demand of secondary energy is ever increasing. Presently, fossil fuels supply majority of it. Energy technologists are currently facing the formidable challenge of meeting this demand with minimum environmental impact, specifically reduced CO2 emission to minimize ‘climate change’. Also new technology development for efficient energy conversion is needed for renewable resource (e.g. biomass) utilization. Rice straw is an agricultural residue and has good calorific value to be used as an energy resource. For the efficient utilization of rice straw, combined cycle gas turbine (CCGT) based polygeneration is a possible option to deliver multiple utilities. In this paper, a polygeneration plant is proposed to deliver power, cooling, heating and desalinated water. It was simulated by Aspen Plus®. Results show that polygeneration has good potential in power generation as well as for various other utilities. Effects of gasification parameters and gas turbine compression ratio are also studied. Results show that optimum equivalence ratio is 3.5–4 for maximum fuel energy savings ratio and for maximum exergy efficiency. Higher GT-cycle compression ratio results more power output but other utility outputs decrease with increase in compression ratio.Copyright

Intelligent Biogas Fuelled Distributed Energy Conversion Technologies: Overview of a Pilot Study in Norway

It is foreseen that distributed power generation, using biogas and natural gas as fuel, will play increasingly important role in the future European energy market. These technologies are presenting controllable power generation capacity as complementary to the installed intermittent renewable power generation in terms of wind and solar.A nationally funded project was initiated in Stavanger, Norway in 2010, led by the Center for Sustainable Energy Solutions (cenSE), to investigate use of existing small scale energy conversion technologies developed for natural gas, using as much as possible biogas mixed with natural gas without any hardware modifications to the energy conversion units. Three test setups with a micro gas turbine (100 kWe), a gas engine (11 kWe) and a short stack of solid oxide fuel cell consisting of six cells (30–40 We) were installed for experimental studies, providing necessary data for model validation and development of data driven models for engine performance monitoring.This paper reports the results of the project, concerning mapping the operational window for use of mixture of simulated biogas (50% methane, 50% CO2) and natural gas for each technology as an enabler of biogas utilization with natural gas as fallback solution. The CO2 reduction potential, when natural gas is replaced with biogas, is also presented. Moreover, the capability of using data driven models based on artificial neural network for online monitoring and control of the engine performance at various operational conditions is shown.Detailed reporting on various aspects of fuel composition and technology impact has been conducted earlier. This paper provides a total overview and a comparison of performance of the technologies tested in this study.Copyright