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Records with Keyword: Natural Gas
Performance Study on a Single-Screw Expander for a Small-Scale Pressure Recovery System
Guoqiang Li, Yuting Wu, Yeqiang Zhang, Ruiping Zhi, Jingfu Wang, Chongfang Ma
March 15, 2019 (v1)
Subject: Other
Keywords: Natural Gas, pressure energy recovery, single-screw expander
A single-screw expander with 195 mm diameter is developed to recover pressure energy in letdown stations. An experiment system is established using compressed air as a working fluid instead of natural gas. Experiments are conducted via measurements for important parameters, such as inlet and outlet temperature and pressure, volume flow rate and power output. The influence of inlet pressure and rotational speed on the performance are also analyzed. Results indicate that the single-screw expander achieved good output characteristics, in which 2800 rpm is considered the best working speed. The maximum volumetric efficiency, isentropic efficiency, overall efficiency, and the lowest air-consumption are 51.1 kW, 83.5%, 66.4%, 62.2%, and 44.1 kg/(kW·h), respectively. If a single-screw expander is adopted in a pressure energy recovery system applied in a certain domestic natural gas letdown station, the isentropic efficiency of the single-screw expander and overall efficiency of the system are... [more]
Life Cycle Assessment of a HYSOL Concentrated Solar Power Plant: Analyzing the Effect of Geographic Location
Blanca Corona, Diego Ruiz, Guillermo San Miguel
November 28, 2018 (v1)
Subject: Energy Policy
Keywords: biomethane, Chile, environment, Kingdom of Saudi Arabia, Life Cycle Assessment (LCA), Mexico, Natural Gas, solar energy, South Africa, Spain
Concentrating Solar Power (CSP) technology is developing in order to achieve higher energy efficiency, reduced economic costs, and improved firmness and dispatchability in the generation of power on demand. To this purpose, a research project titled HYSOL has developed a new power plant, consisting of a combined cycle configuration with a 100 MWe steam turbine and an 80 MWe gas-fed turbine with biomethane. Technological developments must be supported by the identification, quantification, and evaluation of the environmental impacts produced. The aim of this paper is to evaluate the environmental performance of a CSP plant based on HYSOL technology using a Life Cycle Assessment (LCA) methodology while considering different locations. The scenarios investigated include different geographic locations (Spain, Chile, Kingdom of Saudi Arabia, Mexico, and South Africa), an alternative modelling procedure for biomethane, and the use of natural gas as an alternative fuel. Results indicate that... [more]
Techno-Economic Analysis of Combining Petroleum Coke and Natural Gas for Efficient Liquid Fuels Production
Ikenna Joseph Okeke, Thomas A Adams II
October 30, 2018 (v1)
Subject: Uncategorized
Waste petcoke can be converted to liquid fuels instead of stockpiling which reduces the net CO2 emission by displacing additional petroleum usage. In this study, three petcoke to liquid fuels designs were compared based on the following performance criteria: conversion efficiency, economics, and environmental impacts. The designs considered were petcoke gasification only, a combination of natural gas reforming and petcoke gasification, and natural gas reforming integrated in the petcoke gasification step. The processes were modeled and simulated using a combination of Aspen Plus v10, ProMax, and gProms software. Each of the configurations were designed to operate with and without carbon capture and sequestration (CCS) technology along with a corresponding carbon emission penalty. Performance metrics analyzed were the net present value, minimum diesel selling price, cost of CO2 avoided, and cradle to plant exit gate life cycle greenhouse gas emissions. From the analysis, the integration... [more]
Diesel-Minimal Combustion Control of a Natural Gas-Diesel Engine
Florian Zurbriggen, Richard Hutter, Christopher Onder
October 23, 2018 (v1)
Keywords: closed-loop control, combustion control, Diesel, dual fuel, engine control, extremum seeking, internal combustion engine, Natural Gas, Optimization
This paper investigates the combustion phasing control of natural gas-diesel engines. In this study, the combustion phasing is influenced by manipulating the start and the duration of the diesel injection. Instead of using both degrees of freedom to control the center of combustion only, we propose a method that simultaneously controls the combustion phasing and minimizes the amount of diesel used. Minimizing the amount of diesel while keeping the center of combustion at a constant value is formulated as an optimization problem with an equality constraint. A combination of feedback control and extremum seeking is used to solve this optimization problem online. The necessity to separate the different time scales is discussed and a structure is proposed that facilitates this separation for this specific example. The proposed method is validated by experiments on a test bench.
Approximating Nonlinear Relationships for Optimal Operation of Natural Gas Transport Networks
Kody Kazda, Xiang Li
October 13, 2018 (v1)
Subject: Optimization
Keywords: Compressors, Fuel Cost Minimization Problem, GAMS, Matlab, Natural Gas, Optimization
Source code for the case study presented in the paper "Approximating Nonlinear Relationships for Optimal Operation of Natural Gas Transport Networks". The case study involves solving the compressor fuel cost minimization problem (FCMP) on three simple natural gas networks. For each gas network three different formulations of the FCMP are tested: a common simplified FCMP model (FCMP_S), the novel approximation FCMP model (FCMP_N) that is developed in the paper, and a partially rigorous FCMP model (FCMP_PR) that models components of the model using their most rigorous calculations where feasible. The FCMP for each of these tests was optimized using GAMS, for which the code is provided. The accuracy of each of the three models was then assessed by comparing them to a rigorous simulation. The rigorous simulation was coded in Matlab and is provided, where separate files are used to calculate the rigorous gas pressure drop along a pipeline, and the energy input required for gas compression... [more]
Understanding Continuance Usage of Natural Gas: A Theoretical Model and Empirical Evaluation
Victor Fernández-Guzmán, Edgardo R. Bravo
September 21, 2018 (v1)
Keywords: continuance usage, expectation-confirmation, Natural Gas
The adoption of natural gas increased notably last years, and there is some recognition that it improves the quality of life of inhabitants. While initial acceptance is an essential first step, the continued use is relevant to the long-term success of any technology. However, the literature on energy has focused on adoption and has devoted less attention to models that explain continuance usage. Accordingly, this study developed a model to explain continuance usage, grounded in Expectation-Confirmation Model (ECM). Unlike adoption models, confirmation of previous expectations and satisfaction with the experience of use have a relevant role in this phenomenon. Data was gathered through a questionnaire to 435 users of the service in a Latin American metropolis, and structural equations model was used for analysis. The results show that constructs of the ECM (perceived usefulness, disconfirmation, and satisfaction) influences on continuance intention. While the price impacts as expected,... [more]
Short-Term Load Forecasting of Natural Gas with Deep Neural Network Regression †
Gregory D. Merkel, Richard J. Povinelli, Ronald H. Brown
September 21, 2018 (v1)
Keywords: artificial neural networks, deep learning, Natural Gas, short term load forecasting
Deep neural networks are proposed for short-term natural gas load forecasting. Deep learning has proven to be a powerful tool for many classification problems seeing significant use in machine learning fields such as image recognition and speech processing. We provide an overview of natural gas forecasting. Next, the deep learning method, contrastive divergence is explained. We compare our proposed deep neural network method to a linear regression model and a traditional artificial neural network on 62 operating areas, each of which has at least 10 years of data. The proposed deep network outperforms traditional artificial neural networks by 9.83% weighted mean absolute percent error (WMAPE).
Combining Petroleum Coke and Natural Gas for Efficient Liquid Fuels Production
Ikenna J Okeke, Thomas A Adams II
August 28, 2018 (v1)
This work explores the technical feasibility and economic profitability of converting petroleum coke (petcoke) and natural gas to liquid fuels via Fischer-Tropsch synthesis. Different petcoke conversion strategies were examined to determine the conversion pathway which can be competitive with current market prices with little or no adverse environmental impacts. Three main design approaches were considered: petcoke gasification only, combined petcoke gasification and natural gas reforming through traditional processing steps, and combined petcoke gasification and natural gas reforming by directly integrating the gasifier’s radiant cooler with the gas reformer. The designs investigated included scenarios with and without carbon capture and sequestration, and with and without CO2 emission tax penalties. The performance metrics considered included net present value, life cycle greenhouse gas emissions, and the cost of CO2 avoided. The design configuration that integrated natural gas refor... [more]
Combining Biomass, Natural Gas, Carbonless Heat to produce liquid fuels
Leila Hoseinzade, Thomas A Adams II
August 15, 2018 (v1)
Keywords: Biomass, Carbonless Heat, Natural Gas, Polygeneration
In this study, a new Biomass-Gas-Nuclear heat-To-Liquid fuel (BGNTL) process is presented which uses high-temperature nuclear heat as the heat source for steam methane reforming (SMR). This process co-produces liquid fuels (Fischer-Tropsch liquids, methanol and DME) and power. The BGNTL process was simulated using a combination of different software packages including gPROMS, MATLAB, ProMax, and Aspen Plus. This included the use of a rigorous multi-scale model for the nuclear-heat-powered SMR reactor which was developed in a prior work in gPROMS. Energy efficiency and cradle-to-grave life cycle inventory and life-cycle impact analyses of greenhouse gas (GHG) emissions were accomplished to analyze the environmental impacts of the BGNTL system. Plant performance was compared with a base case Biomass-Gas-To-Liquid (BGTL) process at the same size. In both processes, a carbon capture and storage (CCS) option is considered. It has been found that both processes result in negative total life... [more]
Aspen Plus Simulation of Biomass-Gas-and-Nuclear-To-Liquids (BGNTL) Processes (Using CuCl Route)
James Alexander Scott, Thomas Alan Adams II
August 7, 2018 (v1)
These are Aspen Plus simulation files for a Biomass-Gas-and-Nuclear-To-Liquids chemical plant (a conceptional design), which uses the Copper-Chloride route for hydrogen production. This is a part of a larger work (see linked LAPSE record for pre-print and associated publication in Canadian J Chem Eng). Process sections and major units in this simulation include: Gasification, Integrated-Gasification-Methane-Reforming, Pre-Reforming, Water Gas Shift, Autothermal Reforming, Syngas Blending and Upgrading, Solid Oxide Fuel Cell power islands, Fischer-Tropsch Synthesis, Methanol Synthesis, Dimethyl Ether Synthesis, Heat Recovery and Steam Generation, CO2 Compression for Sequestration, Cooling Towers, and various auxiliary units for heat and pressure management. See the linked work for a detailed description of the model.
Biomass-Gas-and-Nuclear-To-Liquids (BGNTL) Processes Part I: Model Development and Simulation
James Alexander Scott, Thomas Alan Adams II
August 7, 2018 (v1)
New polygeneration processes for the co-production of liquid fuels (Fischer-Tropsch liquids, methanol, and dimethyl ether) and electricity are presented. The processes use a combination of biomass, natural gas, and nuclear energy as primary energy feeds. Chemical process models were created and used to simulate candidate versions of the process, using combinations of models ranging from complex multi- scale models to standard process flowsheet models. The simulation results are presented for an Ontario, Canada case study to obtain key metrics such as efficiency and product conversions. Sample Aspen Plus files are provided in the supplementary material to be used by others.
Biomass-Gas-and-Nuclear-To-Liquids Aspen Plus Simulations
Leila Hoseinzade, Thomas A. Adams II
December 7, 2018 (v2)
In this paper, several new processes are proposed which co-generate electricity and liquid fuels (such as diesel, gasoline, or dimethyl ether) from biomass, natural gas and heat from a high temperature gas-cooled reactor. This carbonless heat provides the required energy to drive an endothermic steam methane reforming process, which yields H2-rich syngas (H2/CO>6) with lower greenhouse gas emissions than traditional steam methane reforming processes. Since downstream Fischer-Tropsch, methanol, or dimethyl ether synthesis processes require an H2/CO ratio of around 2, biomass gasification is integrated into the process. Biomass-derived syngas is sufficiently H2-lean such that blending it with the steam methane reforming derived syngas yields a syngas of the appropriate H2/CO ratio of around 2. In a prior work, we also demonstrated that integrating carbonless heat with combined steam and CO2 reforming of methane is a promising option to produce a syngas with proper H2/CO ratio for Fischer... [more]
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