The economic value and satisfaction of substituting LPG in households by a biogas network: A case study of Bo Rae Subdistrict in Chai Nat Province Thailand

Economic value and satisfaction of substituting LPG by a biogas network in households of Bo Rae Subdistrict, Chai Nat Province, Thailand were investigated. This project was undertaken through collaboration between the Ministry of Energy and Phairat Farm. The Thai Government supported investment in the construction of biogas production and network piping systems for transporting biogas to households. Phairat Farm allocated an area of land to construct the biogas production system and provided support with the raw materials for biogas. These raw materials were pig manure and wastewater as by-products from pig farming. Income and expenses of a 15-year plan project were considered and analysed to assess the economic value using net present value (NPV), internal rate of return (IRR) and payback period (PB) in 3 case; (1) income came from payment for biogas by each household at a rate of 50 baht per month and selling dried sediments from the biogas production system, (2) income came from substituting LPG at price of 30 THB/kg and (3) income came from payment for biogas by each household, selling dried sediments, substituting LPG and selling carbon credit. Results showed that only the first case was not profitable because payback period over 15 year. Then, a biogas user satisfaction survey was also conducted using 136 questionnaires. The samples size was determined by Taro Yamane's equation to achieve 95% confidence level and ±5% uncertainty. Data were collected and analysed to measure satisfaction level in three aspects; (1) an analysis comprising management, usage, and maintenance of the biogas system, (2) environmental impact and (3) overall satisfaction level. Results showed that the samples were very satisfied with management, usage and maintenance of the biogas system. Income was only the main influential factors. For the environmental impact and overall satisfaction level, the samples were also very satisfied

Biogas and biomass pellet production from water hyacinth

The prime objective of this paper was to produce the biogas and biomass pellets from water hyacinth. The leaf and petiole were chopped, grind, squeezed and then separated into two parts as squeezed out juice and remaining fiber. The squeezed out water as water hyacinth juice (SWWH) was used to produce biogas with microorganisms at a ratio of 1: 1 (8 liters of SWWH/8 liters of microorganisms). Water hyacinth fiber (WHF), with a moisture content of 10.57% wet basis, was used to produce biomass pellets. The results showed that a total of 458.44 liters of biogas was produced from SWWH with microorganisms consisting of 68.67% CH4, 18.23% CO2, and 13.10% other gases. Specific methane yield and the potential to biodegrade methane were 237.37 L CH4/kgVSadded and 51.89%, respectively. Test results of biomass pellets from water hyacinth with water ratio of 10:90 indicated that the bulk density, diameter, durability, fines content, length, and moisture of the pellets met the criteria of the US Standards (PFI standard), except for inorganic ash and chloride contents

Improving Biomethanol Synthesis via the Addition of Extra Hydrogen to Biohydrogen Using a Reverse Water–Gas Shift Reaction Compared with Direct Methanol Synthesis

Conventionally, methanol is derived from a petroleum base and natural gas, but biomethanol is obtained from biobased sources, which can provide a good alternative for commercial methanol synthesis. The fermentation of molasses to produce biomethanol via the production of biohydrogen (H2 and CO2) was studied. Molasses concentrations of 20, 30, or 40 g/L with the addition of 0, 0.01, or 0.1 g/L of trace elements (TEs) (NiCl2 and FeSO4·7H2O) were investigated, and the proper conditions were a 30 g/L molasses solution combined with 0.01 g/L of TEs. H2/CO2 ratios of 50/50% (v/v), 60/40% (v/v), and 70/30% (v/v) with a constant feed rate of 60 g/h for CO2 conversion via methanol synthesis (MS) and the reverse water–gas shift (RWGS) reaction were studied. MS at temperatures of 170, 200, and 230 °C with a Cu/ZnO/Al2O3 catalyst and pressure of 40 barg was studied. Increasing the H2/CO2 ratio increased the maximum methanol product rate, and the maximum H2/CO2 ratio of 70/30% (v/v) resulted in methanol production rates of 13.15, 17.81, and 14.15 g/h, respectively. The optimum temperature and methanol purity were 200 °C and 62.9% (wt). The RWGS was studied at temperatures ranging from 150 to 550 °C at atm pressure with the same catalyst and feed. Increasing the temperature supported CO generation, which remained unchanged at 21 to 23% at 500 to 550 °C. For direct methanol synthesis (DMS), there was an initial methanol synthesis (MS) reaction followed by a second methanol synthesis (MS) reaction, and for indirect methanol synthesis (IMS), there was a reverse water–gas shift (RWGS) reaction followed by methanol synthesis (MS). For pathway 1, DMS (1st MS + 2nd MS), and pathway 2, IMS (1st RWGS + 2nd MS), the same optimal H2/CO2 ratio at 60/40% (v/v) or 1.49/1 (mole ratio) was determined, and methanol production rates of 1.04 (0.033) and 1.0111 (0.032) g/min (mol/min), methanol purities of 75.91% (wt) and 97.98% (wt), and CO2 consumptions of 27.32% and 57.25%, respectively, were achieved

Comparison of molasses conversion to biomethanol by biohydrogen pathway with biogas route in engineering and cost assessment: Thailand case

Biomethanol is a significant chemical in biochemicals and biofuels. Molasses is interested in producing biogas and biohydrogen for biomethanol. Biohydrogen, Enterobacter aerogenes digested molasses obtaining value organic chemicals and biohydrogen in appropriate ratios of H2/CO2 then transforming to H2/CO by RWGS. Biogas was converted to syngas then methanol synthesis. The biogas pathway was 4 steps and it was appropriate for sailing single product as biomethanol. The biohydrogen pathway was 3 steps and obtained income both valuable substances and biomethanol. Operating expenditure for 1 kg methanol by biohydrogen experiment and theory were 4.4148 and 4.0912 USD comparing with biogas 0.3446 USD based on commercial methanol price 0.449 USD/kg. The sale prices per kg of biomethanol by biohydrogen were 6.7243 USD (Exp.) and 5.7500 USD (Theory) comparing with biomethanol sailing from biogas pathway at 0.4486 USD. Margin caps were 30.19%, 39.66%, and 40.55% for biogas pathway, biohydrogen experiment and theory route respectively