Добірка наукової літератури з теми "Methanol generation form a sustainable route"

Methanol is considered a sustainable alternative energy source due to its ease of storage and high-octane rating. However, the conventional methanol production process is accompanied by resource consumption and significant greenhouse gas emissions. The electrochemical reaction of electrochemically reacted hydrogen (H2) with captured carbon dioxide (CO2) offers an alternative route to methanol production. This paper presents a new green poly-generation system consisting of a parabolic trough solar collector (PTC) unit, an organic Rankine cycle (ORC) unit, a CO2 capture unit, an alkaline electrolysis unit, a green methanol synthesis and distillation unit, and a double-effect lithium bromide absorption refrigeration (ARC) unit. The system mainly produced 147.4 kmol/h of methanol at 99.9% purity, 283,500 kmol/h of domestic hot water, and a cooling load of 1341 kW. A total 361.34 MW of thermal energy was supplied to the ORC by the PTC. The alkaline electrolysis unit generated 464.2 kmol/h of H2 and 230.6 kmol/h of oxygen (O2) while providing H2 for methanol synthesis. Thermodynamic and economic analysis of the system was carried out. The energy and exergy efficiency of the whole system could reach 76% and 22.8%, respectively. The internal rate of return (IRR) for the system without subsidies was 11.394%. The analysis for the methanol price showed that the system was economically viable when the methanol price exceedsed$363.34/ton. This new proposed poly-generation system offers more options for efficiently green methanol production.

Abstract In the past two decades, graphene has been one of the most studied materials due to its exceptional properties. The scalable route to cost-effective manufacture defect-free graphene has continued to remain a technical challenge. Intrinsically defect-free graphene changes its properties dramatically, and it is a challenging task to control the defects in graphene production using scaled-down subtractive manufacturing techniques. In this work, the exfoliation of graphite was investigated as a sustainable low-cost graphene manufacturing technique. The study made use of a simple domestic appliance e.g., a kitchen blender to churn graphene in wet conditions by mixing with N-Methyl-2-pyrrolidone (NMP). It was found that the centrifugal force-induced turbulent flow caused by the rotating blades exfoliates graphite flakes to form graphene. The technique is endowed with a high yield of defect-free graphene (0.3 g/h) and was deemed suitable to remove 10% fluoride content from the water and color absorption from fizzy drinks.

Energy derived from biomass is a very promising energy alternative especially when we compare the same with fossil fuels (coal, liquid fossil fuels, etc.) as the plants can absorb the carbon dioxide during the photosynthesis process and therefore can reduce the greenhouse gas (GHG) emissions generated from fossil fuels. Further, the utilization of biomass in various biomass-based thermochemical conversion technologies could help to convert waste bio-resources into bio-energy. This review paper provides an overview of various types of available biomass resources along with their chemical composition and physical properties and their utilization for the generation of power (electricity) as an alternative to coal for power generation from a Thermal Power Plant or useful form of heat or fuels/chemicals for various other industrial processes. It includes the merits and demerits of biomass-fired thermal power plants with reference to efficiency, environmental emissions, and logistics, supply chain and storage for biomass. These review papers attempt to bring forward the effective methods which could be adopted for the efficient utilization of biomass for the purpose of power generation from biomass-based thermal power plants. Further, this could also help to substantially reduce green house gas emissions and carbon footprint and help to achieve sustainable development goals.

The conversion of CO2 gas from the global emission to methanol can be a route to look at in addressing greenhouse gas (GHG) issues. Photocatalysis has been attracting attention in the conversion of CO2 to methanol, as it is seen to be one of the most viable, economic, and sustainable strategies. The biggest hindrance to the use of metal oxide photocatalysts was the poisoning by sulfur content in the CO2 gas feedstock. Therefore, in the development of photocatalysts using metal oxide-based additives, the metal needs to be in the form of metal sulfides to avoid catalyst poisoning due to the presence of H2S. The magnesium sulfide-based TiO2 (MgS-TiO2) photocatalyst has not been synthesized and studied for its photocatalytic potential. In this study, a novel MgS-TiO2 photocatalyst was synthesized using a combination of wet impregnation and hydrothermal method and characterized to determine the physical and chemical properties of the photocatalyst. Characterization results have shown the presence of MgS on the native TiO2 photocatalyst. The optimization of MgS-TiO2 formulation was conducted, wherein the MgS and TiO2 ratio of 0.5 wt % has been shown to give the highest methanol yield of 229.1 μmol/g·h. The photocatalytic parameter optimization results showed that temperature and catalyst loading were the most important factors that impacted the photocatalytic process. In contrast, reaction time had the least significant effect on the CO2 photocatalytic reduction to methanol. This concludes that the MgS-TiO2 photocatalyst has potential and can be used for the photocatalytic reduction of CO2 to methanol.

The possibility of using renewable feedstocks for biodiesel production and reducing gas emissions makes it an attractive large-scale substitute to traditional fossil diesel. Although renewability is one of the main driving forces in biodiesel use, traditional production routes employ methanol as the transesterification agent, a chemical generated from fossil carbon. Aiming at further improving biodiesel’s sustainable performance, the replacement of methanol by ethanol has been proposed. Use of the ethylic production route could further reduce CO2 emissions, energy consumption and generate more jobs. The objective of this study is to unveil whether substituting methanol for ethanol does indeed result in a less carbon and energy intensive production chain while also increasing job generation and decreasing social strife. To assess production chain performance a lifecycle approach was used composed by: (i) Data assemblage from literature to represent the ethylic/methylic biodiesel systems; (ii) Construction of quantitative indicators to compare material and energetic flows; and (iii) Principal Component Analysis (PCA) for data interpretation and relevance ranking of calculated social/environmental indicators. Focus was given to CO2 emissions, energy consumption and social aspects of sustainability. Results show that use of ethanol does indeed reduce CO2 emissions, due to extra agricultural carbon sinks in the production chain but increases energy consumption and energy loss. Methanol also resulted in a chain with higher average wages, more jobs generated and less forced labor cases but with a higher accident rate and a high salary disparity. PCA showed that carbon intensity is one of the most important environmental metrics while energy consumption was considered secondary, but the high correlation between these aspects highly impact chain sustainability. PCA also greatly differentiated agricultural and industrial links of respective production chains, with industrial links being governed by CO2 emissions and process safety and agricultural links by water consumption, land use and energy loss. A distinct tradeoff was seen between environmental and social considerations of sustainability and between carbon intensity and energy consumption reductions. As a result, substitution is only justified in scenarios in which CO2 emissions outweigh energy intensity and social aspects.

The synthesis of ZSM-22 zeolite has been extensively studied due to its properties of form selectivity, acidity and hydrothermal stability, which is applied in important reactions in the areas of petroleum refining and petrochemicals. In view of this, the present work studied different approaches of synthesis of ZSM-22 using: 1-diaminohexane as a structure directing agent, (ii) methanol and seed crystals, (iii) aging of the synthesis gel with addition of polymer, surfactant and silane and (iv) starch, calcium carbonate and silanized silica with subsequent desilication. Thus, the effects of these methodologies on the textural properties, acidity and catalytic activity of the zeolites obtained were evaluated. The samples were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, scanning electron microscopy (SEM), ammonia desorption at programmed temperature (NH3-TPD) and thermal analysis (TG/DTG). The catalytic activity and selectivity of the catalysts were evaluated in the model catalytic cracking reaction of n-heptane at 650 °C for 180 min. The synthesis route using methanol and seed crystals allowed obtaining ZSM-22 in 3 h of crystallization, drastically reducing the synthesis time compared to other methodologies. Despite this, the use of 1-diaminohexane led to the obtaining of zeolite with textural properties, acidity and catalytic activity superior to the other samples. The generation of mesoporosity was obtained through the use of silanized silica and subsequent desilication, leading to greater catalytic stability and less deactivation by coke. All catalysts showed similar selectivity to the formation of compounds in the range C2 to C4.

Ammonia (NH3) is a primary form of reactive nitrogen (Nr) which is an essential nutrient for all lives on the earth. Over the past century, the anthropological N2-fixing process in the industry (i.e., the Haber-Bosch process) has contributed to a significant portion of NH3 production, and has also led to the continued accumulation of Nr in our ecosystems that has caused alarming and profound damages to the ecosystems as well as human welfare, as the rate of Nr generation is not balanced by the natural nitrification-denitrification process for its elimination. For example, leakage of excessive nitrate (NO3 −) into the water bodies caused by overfertilization of crop fields and discharged streams from food processing facilities has led to the formation of “dead zones” in coastal areas created by eutrophication. Denitrification in nature is also accompanied by the considerable generation of nitrous oxide (N2O) which possesses century-long stability and a 300-time greater potential for greenhouse effect than CO2. Therefore, restoring the balance between the generation and elimination of Nr is a challenging but urgent task faced by our human beings today. Sustainable solutions to this human-induced matter have been actively pursued in recent years either by converting Nr to harmless N2 (i.e., denitrification), or by enhancing the effective circulation and utilization of Nr in the cycle of the nitrogen element. For instance, the electrochemical reduction of nitrate (NO3RR) is a promising approach as it can eliminate Nr without the need for additional oxidant/reductant. Selective NO3RR toward N2 is highly desirable but remains difficult to achieve due to the high activation barrier for linking two N atoms on typical catalyst surfaces, and thus the coexistence of competing pathways toward other N-containing products. Alternatively, if other forms of Nr in waste resources can be converted to NH3 in an electrochemical device, this process will not only alleviate the environmental impacts of those Nr, but also simultaneously produce NH3 that could substantially decrease the NH3 demand from the Haber-Bosch process, reduce the use of fossil-derived H2 in NH3 production, and decelerate the accumulation of Nr. In this work, we seek to develop an electricity-driven process that can convert various forms of Nr in real waste resources into manageable NH3 products. The key component is a membrane-free alkaline electrolyzer (MFAEL) which transforms Nr into NH3 as the sole N-containing product. With the inexpensive and robust MFAEL system, we achieved an ampere-level partial current density towards NH3 production. By properly choosing the conditions of NH3 collection from MFAEL, continuous production of pure NH3-based chemicals can be realized without the need for additional separation procedures. Techno-economic analysis (TEA) suggests the potential economic feasibility of the waste-to-NH3 process by coupling electrodialysis (ED) for Nr concentration and the MFAEL process for Nr conversion, offering an all-sustainable route for upcycling waste N into the highest-demanded N-based chemical product, so that the growing trend of Nr buildup can be largely decelerated and reversed.

It is estimated that the global annual acids/alkaline wastes are equivalent to 100 million tons. The disposal process of these waste acid/alkaline solution is the direct neutralization process wherein a lot of heat (~1.11 × 1014 kJ/100 million tons) and salts are expelled to the environment, thus causing serious threats to the environment. If the acid/alkali wastes are neutralized in an electrochemical pathway, energy of about 44 TW h can be harvested in the form of electrical energy which offers a unique platform for the simultaneous treatment of industrial acid and alkaline wastes. Therefore, the development of an electrochemical neutralization device may open a new avenue to design novel aqueous energy storage and conversion devices including fuel cells, supercapacitors and batteries to meet future energy demand. The overall neutralization reaction which involves the formation of water and salt does not lead to change in the oxidation state of the participating species which is a major challenge to perform this reaction electrochemically. How to develop a pH driven fuel cell utilizing the energy of neutralization remains a major challenge? How the neutralization driven fuel cells could be used for other applications such as Alcohol reformation and water desalination? By exploiting the pH dependent nature of Hydrogen redox reaction we for the first demonstrated the concept of direct conversion of Neutralization energy into electrical output without consuming any fuel. We named it as Fuel exhaling fuel wherein neutralization energy is converted to electrical energy with simultaneous regeneration of hydrogen fuel at the cathode. This electrochemical neutralization cell employs H+/H2 redox couple to perform the neutralization reaction in an electrochemical pathway and the positive entropy change of the reaction allows nearly 30% of electrical energy to be harvested from the surroundings. The electrochemical neutralization cell (ENC) delivered a peak power density of ~70 mW/cm2 at a peak current density of ~160 mA/cm2 with a cathodic H2 output of ~80 mL in 1 hour. By using electrochemical neutralization as driving force, We could incorporate the additional functionalities of desalination and alcohol reformation into the fuel cell that too with simultaneous generation of electrical energy. By designing a 3-compartment electrochemical cell simultaneous water desalination during electricity production could be achieved by exploiting the electrochemical neutralization reaction as the driving force. This pathway is unprecedented because desalination is achieved in the electrochemical neutralization cell without irreversibly consuming free energy stored in expensive metals as in redox flow batteries and metal ion batteries but by just interconverting the energy of neutralization as an electrical driving force. The device uses acid and alkali as fuels for desalination by performing reversible redox reactions involving only gases, water, H+ and OH- such that the products and reactants of the redox reactions do not poison the desalinated water as in the state-of-the-art electrodialysis process. The electrochemical desalination cell driven by the electrochemical neutralization demonstrates performance metrics comparable to the state-of-the-art desalination processes reported in the literature. Taking it a step further we show the design and performance of an alcohol reforming fuel cell (ARFC) wherein alcohol reformation is coupled with the electricity production. The thermodynamic calculation showed that alcohol reformation which is otherwise a high temperature/pressure catalytic process can be driven at room temperature and pressure during electricity production with the simultaneous generation of pure hydrogen by utilizing the electrochemical neutralization reaction as the driving force. ARFC chemistry is unusual because of its distinctly positive entropic heat which allows ~56 % of the total available energy to be harvested from the surroundings leveraging a thermodynamic efficiency as high as 2.67. This ARFC demonstrates an energy density of ~253 Wh/kg with ~62 % of methanol to hydrogen conversion, Figure 2. Since the hydrogen fuel produced is free from carbon containing impurities, ARFC can be directly utilized as a fuel reservoir for a H2-O2 fuel cell in a tandem configuration. Although the electrochemical neutralization has many promising applications, it is still in the early stages of development. The devices work on the principle of asymmetric electrolyte configuration and as such the low-cost membranes which are stable in highly acidic and alkaline pHs have to be designed for sustainable operation. Different redox couples have to be identified to explore new possibilities and stable and durable electrocatalysts have to be developed to drive the reaction efficiently in respective pH solutions.

AbstractMethanol is a liquid with high energy storage capacity that holds promise as an alternative substrate to replace sugars in the biotechnology industry. It can be produced from CO2 or methane and its use does not compete with food and animal feed production. However, there are currently only limited biotechnological options for the valorization of methanol, which hinders its widespread adoption. Here, we report the conversion of the industrial platform organism Escherichia coli into a synthetic methylotroph that assimilates methanol via the energy efficient ribulose monophosphate cycle. Methylotrophy is achieved after evolution of a methanol-dependent E. coli strain over 250 generations in continuous chemostat culture. We demonstrate growth on methanol and biomass formation exclusively from the one-carbon source by 13C isotopic tracer analysis. In line with computational modeling, the methylotrophic E. coli strain optimizes methanol oxidation by upregulation of an improved methanol dehydrogenase, increasing ribulose monophosphate cycle activity, channeling carbon flux through the Entner-Doudoroff pathway and downregulating tricarboxylic acid cycle enzymes. En route towards sustainable bioproduction processes, our work lays the foundation for the efficient utilization of methanol as the dominant carbon and energy resource.

Testosterone is a male hormone which is being manufactured in pharmaceutical industry for many years. Testosterone is the primary sex hormone and anabolic steroid in males. It is also used as a drug to treat male hypogonadism, gender dysphoria, bone loss, certain types of breast cancer, prostate cancer and hypersexuality [01]. It may also be used to increase athletic ability in the form of doping. Most of the time the current manufacturing routes start from 4 androstene 3,17 dione which is chemically converted to Testosterone by a reduction reaction. In this article we present the development of a second-generation route towards Testosterone via Biocatalysis, using an oxidoreductase enzyme. This results in a more sustainable API Testosterone. The overall PMI decreases from 69 to 44. Consequently, the enzymatic route reduces the environmental impact based on material use by 36%. Via proteomics principles we have been able to develop a generally applicable in-house analysis/method to prove absence of residual enzyme with a detection limit as low as 1 ppm.

Methanol is increasingly being considered as an alternative fuel due to its potential to reduce environmental pollution and its ability to be used directly in internal combustion engines without any engine modification. This study focuses on using biomass as a source for methanol synthesis. The use of biomass for methanol synthesis has two main advantages: it addresses the air pollution caused by biomass incineration, and it generates value-added chemicals from waste biomass. In this work, the suitability and profitability of producing methanol from biomass-derived syngas (bio-syngas) were investigated. Methanol is typically produced in industries by catalytic conversion of syngas obtained from the steam methane reforming process (SMR). However, syngas obtained from biomass gasification is a relatively newer route since this process generates syngas with lower H2 and higher CO2 content. The hydrogen content in biomass is only 5-7%, in comparison to the carbon value of 48-52%, making the choice of gasifying agent and gasifier design crucial as it determines the H2 percentage and tar content in the syngas. Thus, the simulated syngas composition obtained from oxy-steam downdraft gasification was chosen as an input for studying its effect on the final methanol yield. Thermodynamic analysis of methanol generation from both bio-syngas and SMR showed that methanol yield is sensitive to temperature, pressure, and stoichiometric number (S) in both cases. The optimized methanol yield was achieved at 61.87% for SMR-based syngas and 39.54% for bio-syngas at 483 K and 5 MPa, respectively. Before developing an Aspen Plus® model for biomass to methanol (B2M) conversion, a kinetic-based downdraft gasification model was developed in Aspen Plus® software. The model included tar kinetics and considered the downdraft gasification process in four separate zones with major reaction kinetics. The model was validated with literature data for different feedstocks and three different gasifying agents: air, oxygen, and oxy-steam. And as for the methanol generation system, limited literature was available for methanol production via bio-syngas. This thesis includes experiments with simulated bio-syngas composition for methanol production. Methanol synthesis experiments were performed in a high-pressure reactor using commercial Cu/ZnO/Al2O3 catalysts. The experimental values were used for the validation of the Aspen Plus® methanol kinetic model. The methanol yield values were optimized for the parameters like temperature, pressure and the S for the methanol reactor setup. These optimized values of the parameter were then considered for the B2M process optimization as well. Surrogate models were created using multi-variable analysis to predict and optimize the methanol yield value for the entire B2M process. The model predicts that the maximum achievable methanol yield was 37.77% for bio-syngas. This can be achieved at a gasification condition where the Equivalence Ratio (ER), temperature, Steam to Biomass Ratio (SBR) values were 0.2, 1173 K, and 4, respectively. Finally, a techno-economic analysis of B2M process was done to assess the feasibility of this new alternative route in comparison to the existing natural gas reforming process for methanol synthesis. The techno-economic studies show that biomass to methanol technology can be developed in a country like India where surplus biomass is available. This process becomes economically viable at a methanol selling price of Rs 28 per litre or 0.3 Euro per litre and above a plant capacity of 2000 Tonnes per day of methanol production.

As an energy carrier, hydrogen has the potential to boost the transition toward a cleaner and sustainable energy infrastructure. In this context, steam methane reforming coupled with carbon capture through membrane separation is emerging as a potential route for hydrogen generation with a reduced carbon footprint. A potential way to improve the efficiency and reduce costs of the entire process is to integrate the hydrogen production system with a gas turbine power plant, using a fraction of waste heat exhausted to provide the heat and the steam required by the endothermic reforming reaction. The paper assesses the techno-economic performances of a small-scale hydrogen and electricity co-production system, integrating a syngas production section, a gas turbine and a membrane separation unit. The simulation study investigates two main configurations, depending on whether the gas turbine is fed by hydrogen or natural gas. For each configuration, energy and economic performance indices are evaluated varying the main plant operating parameters, i.e. the steam reforming temperature, the permeate sweep dilution, the membrane pressure ratio and the technology of gas turbine.