Showing papers by "Chris Peterson published in 1999"

The effect of biodiesel feedstock on regulated emissions in chassis dynamometer tests of a pickup truck.

Abstract: Six different vegetable oil esters (coconut ethyl ester, used hydrogenated soy methyl ester, rapeseed ethyl ester, mustard ethyl ester, safflower ethyl ester, and a commercial methyl ester of soy oil) were selected to represent a range of iodine numbers from 7.88 to 133. These vegetable oil esters were tested neat and in 20% biodiesel/80% diesel blends in comparison with low sulfur diesel fuel for the effect on regulated emissions. The test vehicle was a pickup truck with a 5.9 L turbo-charged and inter-cooled direct injection diesel engine. The emissions tests were conducted at the Los Angeles County Metropolitan Transit Authority Emissions Testing Facility on a chassis dynamometer. It was found that lower iodine numbers correlated with reduced nitrogen oxides (NOx). As iodine number increased from 7.88 to 129.5 the NOx increased 29.3%. Fatty acids with two double bonds appeared to have more effect on increasing NOx emissions than did fatty acids with one double bond. Changes in carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM) were not linearly correlated with iodine number. It is apparent that the type of feedstock oil affects the characteristics of the biodiesel fuel. The most obvious difference is that the pour point changes with fatty acid composition, however, other fuel characteristics, some of which effect combustion, are also changed. This article reports on a study of biodiesel iodine number on changes in regulated emissions. The results of this and similar studies provide information for developing triglycerides specifically for optimum use in biodiesel. Modern chemical processes and/or plant breeding should make this possible.

One-thousand-hour engine durability test with HySEE and using a 5X-EMA test cycle

Abstract: A modified 1000-h EMA-based test was run on three Yanmar 3TN75E-S 15 kW (20 hp) diesel engines fueled with three different blends of hydrogenated soy ethyl ester (HySEE). Fuels used in the test were 100%, 50%, and 25% blends of HySEE with type 2 diesel fuel (D2). Eight-thousand one-hundred and five liters (2141 gal) of HySEE were produced for the test using the process developed at the Department of Biological and Agricultural Engineering at the University of Idaho. The blends of HySEE performed adequately compared to diesel fuel. However, cold weather operation was a continual challenge. At each of the normal oil change intervals, oil analysis results for wear metals for the 100% HySEE engine were equal to or better than either the 25% HySEE or the 50% HySEE fueled engine. Engine injector pressure and compression was essentially unchanged for all engines over the course of the 1000 h. The engine fueled with 100% HySEE was cleaner and brighter internally than either the 25% HySEE or the 50% HySEE fueled engine. The 25% HySEE fueled engine was overfueled in the torque range according to a post injector pump test.

Continuous flow biodiesel production.

Abstract: Biodiesel, which consists of the fatty acid esters of simple alcohols, is a potential replacement for a portion of thediesel fuel used in transportation. It is produced from both used (oil that has been utilized for frying and discarded) and newvegetable and animal fats and oils. It has several advantages. Among these advantages are its classification as a renewableresource, its ability to reduce HC, CO, and CO2 exhaust emissions, its nontoxic character, and its biodegradability. One ofthe keys to making biodiesel a viable and profitable energy source is the use of a continuous flow transesterification processto reduce time and cost, thereby increasing production and profit. A continuous flow esterification process for producing biodiesel from rapeseed oil and ethanol was investigated. Theequipment consisted of an oil metering pump, centrifugal mixing pump, ethanol and catalyst metering pump, static mixers,laddertype retention reactor, water injection system, and continuous flow centrifugal separating system. The oil feed ratewas 0.38 L/min that yields about three times the weekly production of the existing batch type transesterification system thatproduces 945 L (250 gal) per batch. It was anticipated that if methanol were used instead of ethanol that the flow rate couldbe considerably increased. The system in its present configuration has met ASTM PS12199 standard for free and total glycerol. The centrifugalseparation resulted in release of excessive alcohol vapors. A vapor recovery and condensing system should be installed. Thislatter system could help further reduce costs of the biodiesel produced by recycling some of the alcohol used.

Bezout's theorem and Cohen-Macaulay modules

Abstract: We define very proper intersections of modules and projective subschemes. It turns out that equidimensional locally Cohen-Macaulay modules intersect very properly if and only if they intersect properly. We prove a Bezout theorem for modules which meet very properly. Furthermore, we show for equidimensional subschemes $X$ and $Y$: If they intersect properly in an arithmetically Cohen-Macaulay subscheme of positive dimension then $X$ and $Y$ are arithmetically Cohen-Macaulay. The module version of this result implies splitting criteria for reflexive sheaves.