Substitute natural gas

About: Substitute natural gas is a research topic. Over the lifetime, 1216 publications have been published within this topic receiving 23604 citations. The topic is also known as: synthetic natural gas.

Wheat straw based polygeneration systems integrating the electricity, heating and transport sector

Abstract: To achieve a 100% renewable energy system, plants integrating the electricity, heating and transport sectors in a Smart Energy System are required. In this work, three different polygeneration plants producing biofuels and heat, while interacting with the electricity grid are presented. All plants were based on wheat straw gasification in a low temperature circulating fluidized bed gasifier. High quality bio-oil was produced by catalytically upgrading and condensing the tars in the produced gas. Additionally, bio-ash containing carbon was produced, which acts as fertilizer and carbon sequestration when returned to the fields. The three plants used the tar-free gas to produce electricity, synthetic natural gas (SNG) and dimethyl ether (DME), respectively. The electricity producing plant delivered electricity to the grid, while the SNG and DME production plants used electricity for producing electrolytic hydrogen to boost the fuel production. The plants were evaluated using energy and carbon efficiencies. The analysis showed that all plants achieved total energy efficiencies >83%, including process heat and district heating as by-products. The SNG production plant yielded the highest carbon efficiency (91%) of carbon bound in bio-fuels and bio-ash, followed by the DME (50%) and the electricity production plant (23%).

Hydrogen gasify reacting apparatus of coal for synthetic natural gas production

Abstract: Provided is a hydrogen gasifying reaction apparatus of coal to produce synthetic natural gas through a direct reaction between hydrogen/steam and coal without using a catalyst, and to minimize the generation of hydrogen and carbon monoxide. The hydrogen gasifying reaction apparatus of coal for production of synthetic natural gas is constituted by an entrained flow gasifier(17) where a hydrogen/steam gasifying reaction occurs, compressed gas input units(7,14), a compressed steam input unit(3), a compressed coal input unit(11), non-incinerated residue and ash collection units(22,24,26), and a gas analyzer(20). To control concentration of hydrogen and pressure of a reactor, nitrogen and helium gas(12) are directly injected to the gasifier(17) through pressure controllers(6,13). If the pressure of the gasifier(17) is higher than a certain value, a signal is sent to automatic valves(4,8,15,18,25) so as to stop the gas injection or to release the gas into outside.

Method for producing environment-friendly gas and liquid products by nuclear energy hydrolysate and carbon dioxide and system adopting same

Abstract: The invention provides a system for producing gas and liquid products by nuclear energy hydrolysate and carbon dioxide, comprising a hydrolysis device which can dissolve water into hydrogen and oxygen by nuclear energy, a methanol synthesis device which can produce methanol with carbon dioxide and the hydrogen obtained by hydrolysis, and a dimethyl carbonate synthesis device which can produce dimethyl carbonate by carbon dioxide and methanol. Accordingly, the invention also provides a method for producing gas and liquid products by nuclear energy hydrolysate and carbon dioxide. By effective utilization of hydrogen and oxygen from nuclear energy hydrolysis and carbonaceous substances produced in industrial process or human life, such as carbon dioxide and/or coal and biomass and the like, the system and the method of the invention can produce multiple important gas and liquid products, such as dimethyl carbonate (DMC) and synthetic natural gas (SNG) and the like, and further realize a green and pollution-free production process.

Development of a tar decomposition model for application in a Chemical-Looping Reformer operated with raw gas from a biomass gasifier

Abstract: The production of Synthetic Natural Gas (SNG) represents one of the promising alternatives for biofuel manufacture. The transport sector is where SNG has been identified as having the highest potential in terms of profitability and use efficiency, making it the main aim of production. The key process steps to yield SNG are thermal gasification of biomass followed by methanation of the product gas. But, before reaching methanation the producer gas has to be cleaned from the presence of organic hydrocarbons called tars as well as other contaminants, eliminating them from the mixture of permanent gases. Tars are usually referred to as condensable hydrocarbons that start to condense already at temperatures around 350°C. As the tar condenses it creates operating problems like clogging and blockage of equipment downstream the gasifier. A system for cleaning the producer gas from biomass gasification was developed at Chalmers University of Technology, using a Chemical-Looping Reformer (CLR) for catalytic cracking of tar components. The system was developed for further implementation in the industry with the aim of making it a quicker solution for tar cleaning. The objective of the work was to develop a model for catalytic decomposition of tars, using data available by experiments occurring within the CLR-System at Chalmers. The system is fed with producer gas from Chalmers 2-4MWth biomass gasifier, which goes into the dual-fluidized bed process in which the system consists. The available data for the work was achieved by running the CLR-System with a manganese-based catalyst in the fuel reactor (FR) at three different working temperatures and two oxygen concentrations for reforming of the catalyst in the air reactor (AR). Development of the decomposition model was done firstly by grouping the analyzed tar molecules according to structures, conversions and amount and secondly by study of models describing decomposition processes. From implementation of the developed model ruling first order differential equations in the mathematical software MatLab, it was possible to verify to what extent the model correctly describes the decomposition processes inside the reactor and to have a first impression on how fast the reactions are or how each reaction interacts with the others. Experimental data and simulation results only differed by around 15% maximum. It was conclusive that increasing temperatures and higher oxygen concentrations perform better than lower values, but can also have an influence on the composition of the permanent gases. It was possible to detect some trends on the decomposition pattern but no correlation between working conditions and cracking processes can be made. Finally, temperature seems to have a higher influence on the results than oxygen concentration.