Study on Separating Naphthenic Acids from Diesel Fuel by Microwave Irradiation

The microwave technology was introduced to separate naphthenic acids from diesel fuel. Thedecrease of zeta-potential of electric double layer on the W/O interface and the reduction of diesel fuelviscosity were responsible for the accelerated separation of naphthenic acids under microwave irradiation.The influences of dosage of alkali compound solvent (Mp/MT), irradiation pressure, irradiation time,irradiation power, the settling time and oil phase-to-solvent phase volume ratio (O/S) had been investigated.The optimum process conditions for the refining process were determined. The removal of naphthenicacids reached 98.4% when the optimum conditions were proposed as follows: Mp/MT=1.5, 0.05MPa, 6 min,375W, 25min and O/S=10, respectively. The diesel recovery could reach 99.3% and the quality of thetreated diesel oil was good enough to meet the specification of GB252-2000.

A method for predicting in-cylinder compound combustion emissions

This paper presents a method using a large steady state engine operation data matrix to provide necessary information for successfully training a predictive network, while at the same time eliminating errors produced by the dispersive effects of the emissions measurement system. The steady state training conditions of compound fuel allow for the correlation of time averaged in cylinder combustion variables to the engine out NO x and HC emissions. The error back propagation neural network (EBP) is then capable of learning the relationships between these variables and the measured gaseous emissions, and then interpolating between steady state points in the matrix. This method for NO x and HC has been proved highly successful.

Microalgae for Renewable Energy： Is it a Solution for Global Warming？

Microalgae could be a new sustainable energy source substituted for petroleum. They can produce high value biodiesel, bioethanol, bio-hydrogen, biogas, and that they are able to use waste water and nutrients, allowing for integration of such processes with waste treatment. Open ponds in hectares of area, could remove excess CO2 in atmosphere with photosynthesis. Large scale microalgal production in fields which are not suitable for agriculture could be a solution for CO： capturing from the atmosphere. Sea water could be used for the culture medium not to consume the fresh water. However microalgae reduce the atmospheric CO： while producing the organic material, using the biomass for either fuel production or food, feed, fertilizer, come out with CO2 release to the atmosphere, when burned by the engine, body and/or bacterial activities. So, microalgal growth can＇t reduce the CO2 however makes an important contribution to keep the atmospheric CO2 level stable. Long term solution for removing the CO2, could be possible with making durable biomaterials with microalgal biomass and capture the atmospheric CO2 by fixing into the materials and interrupt the carbon cycle for a long while.

Overview of Past, Present and Future Marine Power Plants

In efforts to overcome an foreseeable energy crisis predicated on limited oil and gas supplies, reserves; economic variations facing the world, and of course the environmental side effects of fossil fuels, an urgent need for energy sources that provide sustainable, safe and economic supplies for the world is imperative. The current fossil fuel energy system must be improved to ensure a better and cleaner transportation future for the world. Despite the fact that the marine transportation sector consumes only 5% of global petroleum production; it is responsible for 15% of the world NOx and SOx emissions. These figures must be the engine that powers the scientific research worldwide to develop new solutions for a very old energy problem. In this paper, the most effective types of marine power plants were discussed. The history of the development of each type was presented first and the technical aspects were discussed second. Also, the fuel ceils as a new type of power plants used in marine sector were briefed to give a complete overview of the past, present and future of the marine power plants development. Based on the increased worldwide concerns regarding harmful emissions, many researchers have introduced solutions to this problem, including the adoption of new cleaner fuels. This paper was guided using the same trend and by implementing the hydrogen as fuel for marine internal combustion engine, gas turbines, and fuel cells.

The Impact of Ethanol as a Fuel in the Gas Emissions

This work deals with the examination of farm tractor with diesel engine from the viewpoint of power and gas emissions, using as fuel diesel-ethanol mixtures. A series of laboratory instruments was used for the realization of the experiments. The tractor engine is functioning under full load conditions. The experimental results have shown small reduction of power engine with simultaneously remarkable reduction of CO and HC emissions.

The experimental study on combustion characteristics and emissions of a CMM fueled engine

In this paper, an experimental study on combustion characteristics and emissions of a single cylinder spark ignition engine fueled with coal-mine methane （CMM） is investigated under various loads. CMM is simulated by the compressed nature gas（ CNG）/nitrogen blend fuels. Based on experiment results, it is shown that under 0% - 35% nitrogen volume fraction in CNG/nitrogen blends, the maximum cylinder pressure, the maximum rate of pressure rise and the rate of heat release decrease, the flame propagation period increases, the center of heat release curve is closed to the top dead centre （TDC）markedly with the increase of nitrogen volume fraction. Meanwhile, the hydrocarbon （HC）, CO emissions increase, the NOx emission decreases apparently with the increase of nitrogen volume fraction.

Performance and Emission Characteristics of Tylosema Esculentum Biodiesel in a Diesel Engine： An Experimental Investigation

Biodiesel derived from indigenous feed stocks such as Tylosema esculentum kernel oil is deemed a feasible alternative to petroleum diesel for the diesel engine. This paper presents results of investigation of performance and emissions characteristics of diesel engine using Tylosema biodiesel. In this investigation, Tylosema biodiesel was prepared, analyzed and compared with the performance of petroleum diesel fuel using a single cylinder compression ignition diesel engine. The specific fuel consumption, engine torque, engine brake power, hydrocarbons, carbon monoxide and carbon dioxide were analyzed. The tests showed a decrease in engine brake power and torque with increase in engine load, while specific fuel consumption showed an increasing trend with maximum variation of 33% between the two fuels at engine load of 90%. Emission levels of hydrocarbons, carbon monoxide and carbon dioxide showed an increasing trend with increase in load for both fuels. Tylosema biodiesel produced significantly lower concentrations of hydrocarbons than petroleum diesel, while levels of carbon dioxide and carbon monoxide were largely comparable to those of petroleum diesel. Soot production from combustion ofTylosema biodiesel was found to be approximately 98% lower than that from combustion of petroleum biodiesel, demonstrating insignificant contribution to environmental pollution.

Effect of dry density on ^(125)I diffusion in GMZ bentonite

Gaomiaozi （GMZ） bentonite is regarded as the favorable candidate backfilling material for a potential repository in China. It is important to understand the diffusion behavior of ^125I in GMZ bentonite and compare the diffusion behavior in GMZ and other types of bentonite like MX-80, Avonlea, etc. Therefore, through- and out-diffusion experiments were conducted to obtain the effective diffusion coefficient （De） and distribution coefficient （Kd）. A computer code named Fitting for diffusion coefficient （FDP） was used for the experimental data processing and theoretical modeling. At the dry density of GMZ bentonite from 1600-2000 kg/m^3, the De values of ^125I were （2.4-20.4）×10 ^-12 m^2/s and Ka values were constants. At dry density above 1800 kg/m^3, the diffusion behaviors were almost the same, indicating that the anion exclusion was ineffective. Out-diffusion results showed that the species of ^125I may be changed during the diffusion processing. It was probably caused by some organic mat- ters or reducing substances in GMZ bentonite. Since the main composition of bentonite is montmorillonite, similar diffusion parameters were obtained in GMZ and other types of bentonite. The relationship of DE and accessible porosity （εacc） could be described by Archie＇s law with exponent n = 1.2-2.8 for ^125I diffusion in bentonite, whereas n = 2.0 in GMZ bentonite. Fur- thermore, bentonite with the dry density of 1800 kg/m^3 was proposed as the backfilling materials used in the construction of high level radioactivity waste repository.