scholarly journals Modeling the Feasibility of Using Solar Thermal Systems for Meeting the Heating Requirements at Corn Ethanol Production Facilities

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Elizabeth Ehrke ◽  
John R. Reisel
Keyword(s):  
Natural Gas ◽  
Ethanol Production ◽  
Thermal Energy ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Thermal Systems ◽  
Makeup Water ◽  
Gas Consumption ◽  
Natural Gas Consumption ◽  
Production Facilities

While ethanol use as a vehicle fuel has been promoted as a renewable alternative to fossil fuels, current production methods of ethanol from corn feedstock rely heavily on the combustion of nonrenewable fuels such as natural gas. Solar thermal systems can provide a renewable energy source for supplying some of the heat required ethanol production. In this paper, a model to analyze the feasibility of using solar thermal energy to reduce natural gas consumption in ethanol production is described and applied. Sites of current ethanol production facilities are used to provide a realistic analysis of the economic feasibility of using solar thermal energy in the ethanol production process. The results show that it is not reasonable to expect to replace all of the natural gas consumption in the heating processes in ethanol production but that application of solar thermal energy can be applied to a specific subsystem such as the preheating of boiler makeup water. Profitability of systems for replacing a fraction of the natural gas is analyzed. It is found that both location and local natural gas prices are important in determining whether to pursue such a project and that solar thermal systems should have long-term profitability.

scholarly journals Solar Integrated Anaerobic Digester: Energy Savings and Economics

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4292
Author(s):  
Lidia Lombardi ◽  
Barbara Mendecka ◽  
Simone Fabrizi
Keyword(s):  
Anaerobic Digestion ◽  
Natural Gas ◽  
Economic Analysis ◽  
Thermal Energy ◽  
Economic Feasibility ◽  
Solar Thermal ◽  
Base Case ◽  
Economic Sustainability ◽  
Solar Thermal Energy ◽  
Solar Integration

Industrial anaerobic digestion requires low temperature thermal energy to heat the feedstock and maintain temperature conditions inside the reactor. In some cases, the thermal requirements are satisfied by burning part of the produced biogas in devoted boilers. However, part of the biogas can be saved by integrating thermal solar energy into the anaerobic digestion plant. We study the possibility of integrating solar thermal energy in biowaste mesophilic/thermophilic anaerobic digestion, with the aim of reducing the amount of biogas burnt for internal heating and increasing the amount of biogas, further upgraded to biomethane and injected into the natural gas grid. With respect to previously available studies that evaluated the possibility of integrating solar thermal energy in anaerobic digestion, we introduce the topic of economic sustainability by performing a preliminary and simplified economic analysis of the solar system, based only on the additional costs/revenues. The case of Italian economic incentives for biomethane injection into the natural gas grid—that are particularly favourable—is considered as reference case. The amount of saved biogas/biomethane, on an annual basis, is about 4–55% of the heat required by the gas boiler in the base case, without solar integration, depending on the different considered variables (mesophilic/thermophilic, solar field area, storage time, latitude, type of collector). Results of the economic analysis show that the economic sustainability can be reached only for some of the analysed conditions, using the less expensive collector, even if its efficiency allows lower biomethane savings. Future reduction of solar collector costs might improve the economic feasibility. However, when the payback time is calculated, excluding the Italian incentives and considering selling the biomethane at the natural gas price, its value is always higher than 10 years. Therefore, incentives mechanism is of great importance to support the economic sustainability of solar integration in biowaste anaerobic digestion producing biomethane.

Production of Solar Hybrid Fuels of DME, Methanol and H2 in Australia and Shipping to Japan

Solar Energy ◽  
2005 ◽  
Author(s):  
Yutaka Tamaura ◽  
Hiroshi Kaneko ◽  
Akinori Fuse ◽  
Hideyuki Ishihara
Keyword(s):  
Natural Gas ◽  
Solar Energy ◽  
Thermal Energy ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Mixed Gas ◽  
Combined Process ◽  
Emission Process ◽  
Zero Emission ◽  
The One

Solar hybrid fuel production from natural gas using concentrated solar thermal energy in Australia was studied, assuming that 54.6MW/(one unit of solar farm) of the concentrated solar thermal energy is used for the endothermic process of stream reforming (solar steam reforming; SSR) with total solar energy conversion efficiency of 45.5% (120MW of heliostat field; one unit of solar farm). With 23 units of the solar farm, natural gas of 2516t/d can be reformed by the SSR. To ship the product fuel to Japan by existing tankers, the syngas (CO + 3H2) produced by the SSR is separated into one mole of H2 (375t/d) and the mixed gas of one mole of CO and two moles of H2 which is converted to one mole of methanol (6000t/d) to be shipped by existing tankers. The one mole of H2 will be used in Australia as the H2 fuel with 25% solar share (CO2 reduction). To improve cost barrier between oil and the methanol produced by SSR, the CO2 zero emission process of the combined process of SSR and AT (auto-thermal process) is proposed as the one whose methanol cost can be competitive with oil, when carbon tax is introduced. By shipping the methanol produced by the CO2 zero emission process of the combined process of SSR-AT (economically feasible), we can reduce CO2 emission by co-firing coal and methanol at coal-firing power stations in Japan. In this system, an excess H2 fuel with solar energy is produced, and can be used in Australia.

Sign in / Sign up

Export Citation Format

Share Document