Ignition characteristics of pre-combustion plasma jet igniter

At present, aero-engines face a major need to widen the ignition envelope. In order to provide a technical support to expand the high altitude ignition envelope of aero-engines, in this article we propose a novel ignition technology, i.e., "precombustion plasma jet ignition technology". In this paper, we also design a pre-combustion plasma jet igniter. Its discharge characteristics, jet characteristics, and ignition effects are studied. The results show that increasing the equivalent ratio of jet gas can enhance the discharge stability and increase the duty cycle. At the same time, it can reduce working power and energy consumption. The increase of equivalent ratio in jet gas can enhance the length and ignition area of plasma jet.In the process of ignition, the pre-combustion plasma jet igniter has obvious advantages, suchn as shortening the ignition delay time and enlarging the ignition boundary. When the airflow velocity is 39.11 m/s and the inlet air temperature is80℃, compared with the spark igniter and the air plasma jet igniter, the pre-combustion plasma jet igniter has an ignition boundary that is expanded by 319.8% and 55.7% respectively.

Modelling of a tubular membrane contactor for pre-combustion CO_2 capture using ionic liquids:Influence of the membrane configuration, absorbent properties and operation parameters

A membrane contactor using ionic liquids(ILs) as solvent for pre-combustion capture CO_2 at elevated temperature(303-393 K) and pressure(20 bar) has been studied using mathematic model in the present work. A comprehensive two-dimensional(2 D) mass-transfer model was developed based on finite element method. The effects of liquid properties, membrane configurations, as well as operation parameters on the CO_2 removal efficiency were systematically studied. The simulation results show that CO_2 can be effectively removed in this process. In addition, it is found that the liquid phase mass transfer dominated the overall mass transfer. Membranes with high porosity and small thickness could apparently reduce the membrane resistance and thus increase the separation efficiency. On the other hand, the membrane diameter and membrane length have a relatively small influence on separation performance within the operation range.

Gliding arc plasma adjusting pre-combustion cracking products

In view of the difficulty of kerosene-air detonation faced by the application of rotating detonation to aviation engines,in order to improve the kerosene detonation activity,the atmospheric pressure gliding arc plasma is used to conduct secondary adjustment of the pre-combustion cracking products.The results show that the components with larger molecular weight in the pre-combustion cracking products,such as ethylene and methane,can be cracked into highly active species of hydrogen and acetylene by gliding arc plasma.With the increase of the fuel ratio of pre-combustion cracking,the plasma has a more significant effect on the adjustment of high active components.However,as the flow rate of the cracking gas treated by plasma increases,the adjustment effect is obviously reduced.

Characteristics of a pre-combustion plasma jet igniter

Plasma ignition technology has delivered good performance in the aerospace industry. In this study, a pre-combustion plasma jet igniter was designed, and its characteristics were examined from three aspects: the morphology, temperature, and discharge characteristics and process of ignition. Images of the OH distribution were obtained by using an OH Planar Laser-Induced Fluorescence(OH-PLIF) experimental system. Results have shown that the proposed plasma jet had a higher OH concentration, longer length, and larger area than those of a traditional igniter. The stability of discharge of the igniter was improved as the equivalence ratio φ was increased, and reducing gas flow reduced the pulsation of the plasma jet. When the input current was increased from 15A to 35 A, the highest average temperature increased from 5127 K to 7987 K. An increase in the equivalence ratio reduced the region of arc ionization, but expanded the regions of the core combustion reaction and the outer flame. Herein, this study has obtained a deep understanding of the jet and ignition law and developed a new idea for the application of plasma in the ignition field.A pre-combustion plasma jet igniter can significantly improve the efficiency of ignition and shorten the ignition process compared with a traditional igniter.

Pre-combustion mercury removal with co-production of hydrogen via coal electrolysis

Pre-combustion mercury removal via coal electrolysis was performed and investigated on a bench-scale coal electrolytic cell(CEC)systemically,and factorial design was used to determine the effect of different operating conditions(coal particle size,operating temperature,operating cell voltage,and flow rate of slurry)on the percentage of mercury removal,percentage of ash removal,and dry heating value change.The results showed that the operating cell voltage,as well as the interaction between operating cell voltage and coal particle size,are significant factors in the percentage of mercury removal.There is no significant factor in the percentage of ash removal and the dry heating value change,but the coal could be purified while keeping the dry heating value almost constant after electrolysis.A co-product of hydrogen could be produced during coal electrolysis with 50%lower energy consumption compared with water electrolysis.Meanwhile,a mechanism for mercury removal in coal was proposed.The facts indicate that coal electrolysis is a promising method for precombustion mercury removal.

Impact of organic interlayer anions on the CO2 adsorption performance of Mg-Al layered double hydroxides derived mixed oxides

Herein we report a systematical investigation on the promoting effect of the carbon chain length of the intercalated carboxylic anions on the COcapture performance of Mg-Al layer double hydroxides（LDHs）.A series of organo-LDHs were successfully synthesized via co-precipitation and calcination-rehydration methods. All as-prepared samples were characterized by many techniques including XRD, ATR-FTIR, BET,and TGA. The XRD and ATR-FTIR studies indicated that organic anions were successfully intercalated into LDHs. The influence of some important parameters such as calcination temperature, adsorption temperature, and coating with（Li-Na-K）NOmolten salt was investigated. The results exhibited that when the number of carbon is greater than 10, the COcapture capacity steadily increased with the increase in carbon number. After coating with 55 mol%（Li-Na-K）NOmolten salt, the COuptake of LDH-C16 sample with high Mg/Al ratios can be increased up to 3.25 mmol/g. The COadsorption/desorption cycling stability was also studied using temperature swing adsorption, which showed a stable COcapture performance even after 22 cycles. Considering its high COcapture capacity and good cycling stability, this novel COadsorbent is very promising in the sorption-enhanced water gas shift（SEWGS） processes.

CO_2 absorption with ionic liquids at elevated temperatures

COcapture with ionic liquids（ILs） has attracted many attentions, and most works focused on absorption ability at ambient temperatures, while seldom research was concerned at elevated temperatures.This not only limits the COabsorption application at elevated temperature, but also the determination of the operation condition of the COdesorption generally occurring at higher temperature. This work mainly reported COsolubilities in ILs at elevated temperatures and related properties were also provided. 1-alkyl-3-methylimidazolium bis（trifluoromethylsulfonyl）imide（[CnMIm][TfN]） ILs were selected as physical absorbents for COcapture in this work due to their relative higher COabsorption capacities and good thermal stabilities. The long-term stability tests showed that [CnMIm][TfN] is thermally stable at 393.15 K for long time. COsolubilities in [CnMIm][TfN] were systematically determined at temperatures from 353.15 K to 393.15 K. It demonstrated that COsolubility obviously increases with the increase of pressure while slightly decreases with increase of temperature. As the length of alkyl chain on the cation increases, COsolubility in ILs increases. Additionally, the thermodynamic properties including the Gibbs free energy, enthalpy, and entropy of COwere also calculated.

CO_(2) capture RD&D proceedings in China Huaneng Group

CO_(2) capture is an important carbon management route to mitigate the greenhouse gas emission in power sector.In recent years,China Huaneng Group(CHNG)has paid more attention on CO_(2)capture technology development and launched a series of R&D and demonstration projects.In the area of pre-combustion CO_(2) capture technology,GreenGen project initiated by CHNG is the first integrated gasification combined cycle(IGCC)power plant in China.Located in Tianjin,GreenGen aims at the development,demonstration and promotion of a near-zero emissions power plant.An IGCC plant of 250 MW has successfully passed full-scale trial operation.In the next phase,a pre-combustion CO_(2) capture unit will be integrated into the system.Pre-combustion process based on coal chemical process has been developed with lower costs successfully.Regarding to post-combustion CO_(2) capture(PCC),in 2008,CHNG built a 3,000 tpa CO_(2) capture plant,which was the first CO_(2) capture demonstration plant in China.In 2009,CHNG launched a PCC project in Shanghai with a capture capacity of 120,000 tpa CO_(2).Recently,Huaneng Clean Energy Research Institute(CERI)and Powerspan formed a joint venture,Huaneng-CERI-Powerspan(HCP).HCP has completed the technology qualification program to supply carbon capture technology for the CO_(2)capture Mongstad project.Besides these activities mentioned above,feasibility studies and system design for large scale PCC system,have been undertaken by CERI and its partners from Australia,US and Europe.

Best mix of primary energy resources by renewable energy and fossil fuel with CCS in view of security,stability and sustainability——A vision on hydrogen supply chain by organic chemical hydride method

The best mix scenario by renewable energy and fossil fuel with or without CCS(Carbon Dioxide Capture and Storage) would be a solution to compromise Greenhouse Gases emission issue caused by carbon dioxide(CO2),and depletion of crude oil and natural gas reserves.As fossil fuel with pre-combustion CCS means hydrogen manufacturing and also hydrogen can be produced via electrolysis with renewable energy,it is desirable to establish transportation and storage systems of hydrogen as a clean energy.In this paper a vision on Hydrogen Supply Chain by Organic Chemical Hydride(OCH) Method as well as comparison of CCS configuration are discussed.

Techno-economic comparison of three technologies for precombustion CO2 capture from a lignite-fired IGCC

This paper compares the techno-economic performances of three technologies for CO2 capture from a lignite-based IGCC power plant located in the Czech Republic:(1)Physical absorption with a Rectisol-based process;(2)Polymeric CO2-selective membrane-based capture;(3)Low-temperature capture.The evaluations show that the IGCC plant with CO2 capture leads to costs of electricity between 91 and 120€·MWh−1,depending on the capture technology employed,compared to 65€·MWh−1 for the power plant without capture.This results in CO2 avoidance costs ranging from 42 to 84€·tCO2,avoided−1,mainly linked to the losses in net power output.From both energy and cost points of view,the low-temperature and Rectisol based CO2 capture processes are the most efficient capture technologies.Furthermore,partial CO2 capture appears as a good mean to ensure early implementation due to the limited increase in CO2 avoidance cost when considering partial capture.To go beyond the two specific CO2-selective membranes considered,a cost/membrane property map for CO2-selective membranes was developed.This map emphasise the need to develop high performance membrane to compete with solvent technology.Finally,the cost of the whole CCS chain was estimated at 54€·tCO2,avoided−1 once pipeline transport and storage are taken into consideration.

Advancement and new perspectives of using formulated reactive amine blends for post-combustion carbon dioxide (CO_(2)) capture technologies

Chemical absorption using amine-based solvents have proven to be the most studied,as well as the most reliable and efficient technology for capturing carbon dioxide(CO_(2))from exhaust gas streams and synthesis gas in all combustion and industrial processes.The application of single amine-based solvents especially the very reactive monoethanolamine(MEA)is associated with a parasitic energy demand for solvent regeneration.Since regeneration energy accounts for up to threeequarters of the plant operating cost,efforts in its reduction have prompted the idea of using blended amine solvents.This review paper highlights the success achieved in blending amine solvents and the recent and future technologies aimed at increasing the overall volumetric mass transfer coefficient,absorption rate,cyclic capacity and greatly minimizing both degradation and the energy for solvent regeneration.The importance of amine biodegradability(BOD)and low ecotoxicity as well as low amine volatility is also highlighted.Costs and energy penalty indices that influences the capital and operating costs of CO_(2) capture process was also highlighted.A new experimental method for simultaneously estimating amine cost,degradation rate,regeneration energy and reclaiming energy is also proposed in this review paper.

The capture of carbon dioxide by transition metal aluminates, calcium aluminate, calcium zirconate, calcium silicate and lithium zirconate

The capture of CO_(2) by transition metal(Mn,Ni,Co and Zn)aluminates,calcium aluminate,calcium zirconate,calcium silicate and lithium zirconate was carried out at pre-and post-combustion temperatures.The prepared metal adsorbents were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),surface area analysis and acidity/alkalinity mea-surements.The different experimental variables affecting the adsorbents ability to capture CO_(2),such as the mol ratio of metal ions,the pressure of CO_(2),the exposure time and the temperature of the adsorbent were also investigated.Calcium zirconate captured 13.85 wt-%CO_(2) at 650℃ and 2.5 atm and calcium silicate captured 14.31 wt-%at 650℃.Molecular sieves(13X)and carbon can only capture a negligible amount of CO_(2) at high temperatures(300℃–650℃).However,the mixed metal oxides captured reasonable amount of CO_(2) at these higher temperatures.In addition,calcium aluminate,calcium zirconate,calcium silicate and lithium zirconate adsorbents captured CO_(2) at both pre and post-combustion temperatures.The trend for the amount of captured carbon dioxide over the adsorbents was calcium aluminate<lithium zirconate<calcium zir-conate<calcium silicate.

Particuology and climate change

The global concern over the greenhouse gas emissions and its effect on global warming and climate change has focused attention on the necessity of carbon dioxide capture and sequestration. There are many processes proposed to capture carbon either before or after combustion and these processes invariably involve investigation and application of traditional particuology. The solids employed are of different sizes, densities, morphologies, and strengths. Their handling, transportation, recirculation, and reactor applications are the essence of ＇particuology＇. Particuology can play an important and vital role in achieving cost-effective removal of carbon and minimize emissions of greenhouse gases. In this paper, the existing and developing carbon capture processes are briefly reviewed and the opportunities for application of particuology are identified. The review was not intended to be exhaustive. It is only in sufficient detail to make connection between particuology and climate change. For immediate and future challenges of reducing global warming and carbon capture and sequestration, innovative reactor design and application of parricuology is imperative. Expertise and innovation in particuology can greatly enhance the speed of development of those technologies and help to achieve cost-effective implementation. Particuology is indeed intimately related to the climate change and global warming.