Ultra-low CO Research Articles

Extracting high-purity hydrogen via sodium looping-based formic acid dehydrogenation

Formic acid (FA) has been considered as a prospective hydrogen carrier for its potentials to realize hydrogen storage, transportation, and in-situ supply under mild conditions. However, the application of FA dehydrogenation is limited by its unsatisfactory hydrogen concentration and carbon monoxide selectivity. Herein, a sodium looping-based (Na 2 CO 3 ↔NaHCO 3 ) formic acid dehydrogenation (SLFAD) system is proposed for high-purity hydrogen production with ultra-low CO generation via the Na 2 CO 3 ↔NaHCO 3 looping. The SLFAD system consists of three parts, which are FA dehydrogenation reactor (FADR), sorption-enhanced carbon oxide removal reactor (CORR), and sodium-based sorbent regeneration reactor (SSRR). Experimental results proved that no sodium formate and sodium oxalate was formed under NaHCO 3 reduction by H 2 . A comprehensive assessment of the system was carried out to preliminary verify the feasibility and optimize the operation parameters of the SLFAD system. Results indicated that a maximum hydrogen concentration of 97.905 vol%, a minimum CO concentration of 11.97 ppm, and a high hydrogen production rate of 0.99989 kmol H 2 h −1 can be obtained under the conditions of atmospheric pressure, FADR temperature at 80 °C, H 2 O/HCOOH = 1.2, CORR temperature at 80 °C, and Na 2 CO 3 /HCOOH = 1.0. • A sodium looping based formic acid dehydrogenation (SLFAD) concept was proposed. • A high hydrogen concentration of 97.90 vol% can be obtained at low temperatures. • Carbon monoxide concentration can be restricted to be 11.97 ppm via SLFAD process. • Sodium-based absorbent can be regenerated with the achievement of CO 2 capture.

Performance and emissions of camelina oil derived jet fuel blends under distributed combustion condition

Renewable biofuels offer good performance characteristics as fossil liquid fuels while reducing the emission of pollutants and greenhouse gases helping promote sustainability. Colorless distributed combustion (CDC) for gas turbine applications offers robust means of providing understanding of performance and emissions characteristics using liquid biofuels. In this study, performance and emission characteristics are reported from the combustion of a liquid biofuel, hydroprocessed esters and fatty acids synthetic paraffinic kerosene (HEFA-SPK), derived from camelina oil. Currently HEFA-SPK is approved in up to a 50% blend with jet fuel (JP-8) for commercial and military applications. Experiments conducted on various blended ratios of HEFA-SPK to JP-8 are reported, ranging from 100% JP-8 to 100% HEFA-SPK. Experiments were carried out on a swirl-assisted burner at thermal intensity of 5.7 MW/m-atm, with oxidizer preheated and fuel pre-vaporized to 600 K. Distributed combustion conditions were achieved by reducing the oxygen concentration in the oxidizer through adding diluent gases of N2 and CO2 simulating internal entrainment of hot reactive gases. The effect of blended fuel properties on flame structure (through OH* chemiluminescence) and emissions are reported here. HEFA-SPK and JP-8 showed ultra-low NO emission under CDC, ranging between 2 and 2.5 ppm. HEFA-SPK showed significant reduction in CO of up to 50% compared to JP-8 fuel. This study revealed that camelina oil derived fuel produced from biomass can be used as a mixture component with JP-8, maintaining high combustion performance while providing ultra-low CO emission. The biofuels also help support reduction of lifecycle CO2 emission.

Investigation the effect of adding graphene oxide into diesel/higher alcohols blends on a diesel engine performance

ABSTRACTThis article aims to study the influence of the addition of graphene oxide nanoparticles (GO) to diesel/higher alcohols blends on the combustion, emission, and exergy parameters of a CI engine under various engine loads. The higher alcohols mainly n-butanol, n-heptanol, and n-octanol are blended with diesel at a volume fraction of 50%. Then, the 25 and 50 mg/L concentrations of GO are dispersed into diesel/higher alcohols blends using an ultrasonicator. The GO structures are examined using TEM, TGA, XRD and FTIR. The findings show that there is a reduction in pmax. and HRR when adding higher alcohols with diesel fuel. Regarding engine emission, there is a significant improvement in emissions formation with adding higher alcohols. The addition of GO into diesel/higher alcohols blends improves the brake thermal efficiency by 15%. Moreover, the pmax. and HRR are both enhanced by 4%. The CO, UHC and smoke formation are reduced considerably by 40%, 50 and 20%, respectively, while NOx level is increased by 30% with adding GO. Finally, adding high percentages of n-butanol, n-heptanol, and n-octanol with diesel fuel with the presence of GO has the potential to achieve ultra-low CO, UHC, and smoke formation meanwhile keeping high thermal efficiency level.

Combustion Characteristics of a Diesel Engine Fueled by Biodiesel-Diesel-N-Butanol Blend and Titanium Oxide Additives

Jojoba biodiesel is considered a promising feedstock for renewable energy sources in different countries, however, it has a high viscosity which hinders it to be used with high blending ratio with diesel fuel. Meanwhile, there is a new technique which uses the nanoparticles as additives to diesel-biodiesel-alcohol blend to improve diesel engines performance. Therefore, in this study, to enhance the engine combustion and emission characteristics of a diesel engine, the titanium oxide (TiO2) (25 and 50 mg/L) is used as additives of 50% by volume Jojoba biodiesel, 40% diesel, and 10% n-butanol (denoted by J50D10Bu). The addition of TiO2 nanoparticles to J50D10Bu blend shows that the peak pressure and heat release rate are increased up to 2% and 1.5% respectively. Additionally, the bsfc, as well as CO and UHC emissions, are decreased up to 17%, 30%, and 50% respectively, while NOx is increased in average by 30%. Subsequently, adding high jatropha biodiesel ratio (50% by volume) with 10% n-butanol and 40% diesel fuel with the addition of TiO2 nanoparticles has the potential to accomplish ultra-low CO and UHC emissions meanwhile keeping high thermal efficiency level.

Experimental and Numerical Study of the Effect of High Steam Concentration on the Oxidation of Methane and Ammonia during Oxy-Steam Combustion

The effect of high H2O concentration during oxy-steam combustion on the oxidation of methane and ammonia was investigated both experimentally and numerically. Comparison experiments between O2/N2 and O2/H2O atmosphere were performed in a flow reactor at atmospheric pressure covering fuel-rich to fuel-lean equivalence ratios and temperatures from 973 to 1773 K. Experimental results showed that the presence of high H2O concentration dramatically suppressed CO formation at temperatures above 1300 K. High H2O concentrations inhibited NO formation under stoichiometric and fuel-lean conditions but enhanced NO formation under fuel-rich conditions. The chemical kinetic mechanism, which was hierarchically structured and updated, satisfactorily reproduced the main characteristics of CO and NO formation. High H2O concentrations significantly alter the structure of radical pool and subsequently the formation of CO and NO. Ultralow CO concentrations above 1300 K are attributed to the enhancement of CO + OH ⇄ CO2 + H b...

Use of industrial gases in blast-furnace operation

Industrial gases are used in blast-furnace operation to increase the productivity of the furnaces, optimize their gasdynamic and thermal operating conditions, and alleviate adverse environmental effects. The following technologies are examined: enrichment of the blast with oxygen when pulverized coal and other fuels are injected into the furnace; oxygen enrichment of the combustion air in the stoves; the suppression of fume formation during taps and transfers of pig iron; oxygen-assisted blast-furnace smelting with recirculation of the top gas after it has been washed to remove CO 2 (the technology ULCOS ‐ ultra-low CO 2 steelmaking).

Enhancing hydrogen production activity and suppressing CO formation from photocatalytic biomass reforming on Pt/TiO 2 by optimizing anatase–rutile phase structure

The photocatalytic activity in hydrogen production from biomass reforming can be significantly enhanced while keeping ultra-low CO concentration in produced H 2 by tuning the anatase–rutile phase structures of Pt/TiO 2 photocatalysts. Compared with Pt/P25, the overall photocatalytic activity for the photocatalyst with optimized anatase–rutile structure can be enhanced up to 3–5 times, and the CO concentration in hydrogen can be reduced from several thousands ppm to 5 ppm. It is proposed that the anatase–rutile phase structure can not only enhance the charge separation, consequently the activity, but also adjust the surface acid/base property which suppresses the CO formation.

Design and performance of a pressurized cyclone combustor (PCC) for high and low heating value gas combustion

The combustion difficulties for low heating value (LHV) gases derived from biomass fuels via a gasification process have led to more investigations into LHV gas combustors. Cyclone combustors provide good air/fuel mixing with long residence times. In this study, a small-scale pressurized cyclone combustor (PCC) was designed and optimized using computational fluid dynamics (CFD) simulation. The PCC, along with a turbocharger-based, two-stage microturbine engine, was first characterized experimentally with liquefied petroleum gas (LPG) fuel and then with both LPG and LHV gas derived from biomass in dual-fuel mode. The combustor achieved ultra-low CO and NO x emissions of about 5 and 7 ppm, respectively, for LPG fuel and of about 55 and 12 ppm, respectively, in dual-fuel mode at the maximum second-stage turbine speed of 26,000 rpm with stable turbine operation.

O2 plasma-activated CuO-ZnO inverse opals as high-performance methanol microreformer

We report the use of oxygen vacancy-rich CuO-ZnO inverse opals to strikingly enhance the performance of catalytic methanol reforming reaction with a ratio of 1 : 0.125 : 1 (H2O/O2/MeOH) at a low reaction temperature of only 230 °C, yielding complete conversion of methanol, high hydrogen production rate, ultralow CO formation, and outstanding stability.

Development of an Air Assisted Fuel Atomizer (Liquid Siphon Type) for a Continuous Combustor

This research was the study of a fuel injection system in continuous combustor. Air atomizing nozzle is developed to good efficiency injection and used low air pressure (68.95-275.79kPa) to assist the atomizing nozzle. Refined palm oil and automotive diesel oil were the fuels for the experiment for the system of atomization. The atomizer was designed in a manner that air could flow through the small nozzle. Consequently, the low-pressure airflow could induce fuel by siphoning and break oil into small fine droplets that were delivered through the outlet. The aim of design and develop a continuous combustor is emphasized on simplicity for construction, inexpensive, good stability and reduce import fuel for continuous combustor. Material for combustor chamber is stainless steel in order to avoid oxidation at high combustion temperature. The results showed practical combustion performance using refined palm oil as fuel with ultra-low CO and HC emissions less than 206 ppm and 7 ppm. Another main advantage is a clean combustion, as no sulfur content in the fuel. As a result, the combustor performance testing was evaluated with refined palm oil and LPG. By regulating atomizing air pressure between 68.9995- 275.79 kPa (10-40psi, Siphon height 0.45 m) and regulating LPG pressure of 6.8 kPa (1 psi), result showed that 0.0001167-0.00019936 kg/s of fuel consumption, hot gas produced from combustion was in the range of 308-498°C depending on oxidizing air mass flow regulated between 0.0695-0.1067kg/s. The LPG mass flow was regulated 0.000489 kg/s in order to sustain the combustion stability.

Development of an Air Assisted Fuel Atomizer (Liquid Siphon Type) for a Continuous Combustor

This research was the study of a fuel injection system in continuous combustor. Air atomizing nozzle is developed to good efficiency injection and used low air pressure (68.95- 275.79kPa) to assist the atomizing nozzle. Refined palm oil and automotive diesel oil were the fuels for the experiment for the system of atomization. The atomizer was designed in a manner that air could flow through the small nozzle. Consequently, the low-pressure airflow could induce fuel by siphoning and break oil into small fine droplets that were delivered through the outlet. The aim of design and develop a continuous combustor is emphasized on simplicity for construction, inexpensive, good stability and reduce import fuel for continuous combustor. Material for combustor chamber is stainless steel in order to avoid oxidation at high combustion temperature. The results showed practical combustion performance using refined palm oil as fuel with ultra-low CO and HC emissions less than 206 ppm and 7 ppm. Another main advantage is a clean combustion, as no sulfur content in the fuel. As a result, the combustor performance testing was evaluated with refined palm oil and LPG. By regulating atomizing air pressure between 68.9995- 275.79 kPa (10-40psi, Siphon height 0.45 m) and regulating LPG pressure of 6.8 kPa (1 psi), result showed that 0.0001167-0.00019936 kg/s of fuel consumption, hot gas produced from combustion was in the range of 308-498 0 C depending on oxidizing air mass flow regulated between 0.0695-0.1067kg/s. The LPG mass flow was regulated 0.000489 kg/s in order to sustain the combustion stability.

H2 production with ultra-low CO selectivity via photocatalytic reforming of methanol on Au/TiO2 catalyst

H2 with ultra-low CO concentration was produced via photocatalytic reforming of methanol on Au/TiO2 catalyst. The rate of H2 production is greatly increased when the gold particle size is reduced from 10 to smaller than 3nm. The concentration of CO in H2 decreases with reducing the gold particle size of the catalyst. It is suggested that the by-product CO is mostly produced via decomposition of the intermediate formic acid species derived from methanol. The smaller gold particles possibly switch the HCOOH decomposition reaction mainly to H2 and CO2 products while suppress the CO and H2O products. In addition, some CO may be oxidized to CO2 by photogenerated oxidizing species at the perimeter interface between the small gold particles and TiO2 under photocatalytic condition.

Suppressing CO formation by anion adsorption and Pt deposition on TiO 2 in H 2 production from photocatalytic reforming of methanol

H 2 with ultra-low CO concentration less than 10 ppm was produced via photocatalytic reforming of methanol on Pt/TiO 2 catalyst adsorbed with sulfate or phosphate ion. The platinum loaded on TiO 2 not only enhances the rate of H 2 production but also considerably suppresses CO formation. The sulfate and phosphate ions adsorbed on TiO 2 were found to further suppress the CO formation, without evidently decreasing the rate of H 2 production.

The climate change challenge and transitions for radical changes in the European steel industry

This paper presents ideas pertaining to transitions that are envisaged in the steel industry from Cleaner Production (CP) to Systems Innovation. Limits of the socio-technical system and the climate change challenge will induce changes in the production, distribution and consumption patterns of steel and other materials. Insights from industrial economics and evolutionary theory on innovation for sustainable development are needed to assess the rationale behind the adoption and diffusion of new breakthrough technologies named Ultra Low CO 2 Steel making (ULCOS). Evolution in material consumption patterns deserves a special research agenda which focuses upon the long term evolution of the consuming sectors as major changes in the infrastructure and products that support our many energy dependent services (mobility, shelter, heat, light, etc.) are expected. These changes will be significantly amplified by greenhouse gas emission constraints.

The catalytic oxidation of 14CO in a flow reactor used to measure atmospheric hydroxyl radical concentrations

Measurements of ultra-low CO oxidation rates of materials suitable for construction of a hydroxyl radical monitor are described. The procedure consists of passing an ultrapure 14CO tracer over the test material and collecting the resultant 14CO 2. Oxidation rates are measured for stainless steel, aluminum, alumina, titanium, and Teflon. Results show the oxidation rate with aluminum is at least an order of magnitude less than any other material (<10 4 cm −2s −1). These rates are three to four orders of magnitude lower than reported previously in the literature. Application to a ground-based hydroxyl monitor is discussed.