Designing a Surrogate Fuel for Gas-to-Liquid Derived Diesel

Abstract

Synthetic diesel fuel produced from natural gas via gas-to-liquid (GTL) technology is referred to as ultraclean fuel but is still challenged for full certification as diesel fuel. GTL diesel lacks certain hydrocarbons and chemical constituents, which although are benign to the environment, result in a trade-off in performance when used in a diesel engine. To boost GTL diesel physicochemical properties and thereby enable its use in conventional diesel engines, GTL diesel needs improvement. This can be achieved by mixing suitable additives to the GTL diesel and through the development of surrogate fuels that have fewer components. Screening of thousands of additives is a tedious task and can be done efficiently via computer based modeling to quickly and reliably identify a small number of promising candidates. These models are used to guide the formulation of five surrogates and predict their physicochemical properties. These surrogates are further verified using rigorous mathematical tools as well as through advanced experimental techniques. An optimal surrogate MI-5 is identified, which closely mimics GTL diesel-conventional diesel blends in terms of its physicochemical properties. An engine study for the surrogate is also performed to understand the effect of physicochemical properties on combustion as well as the emission behavior of the fuel. MI-5 exhibited an optimal torque at higher load conditions. A reduction of 11.26% NOx emission for MI-5 is observed when compared to conventional fuel. At higher loads, diesel fuel surpasses the total hydrocarbon (THC) emissions for both the surrogate and the GTL fuel. No significant variation in CO and CO2 emissions for MI-5, GTL diesel and conventional diesel is observed. Analysis of combustion as well as emission behavior of the fuels helps to understand the role of physicochemical properties on the performance of the fuel.

Enhancing the lubricity of gas-to-liquid (GTL) paraffinic kerosene: impact of the additives on the physicochemical properties

“…This study therefore aimed at addressing the lubricity challenge of SPK fuel while determining the trade-offs of these additives on the critical properties of the fuel. Additionally, improving the competences of an already developed model [19][20][21], that has been used to predict the fuel's lubricity as well as other properties is reported in this study.…”

“…The first stage was to experimentally test the critical physicochemical properties of the fuels. The second stage was to forward samples compositions and properties to the mathematical modelling team at Dalian Technical University, where they utilized a previously developed mathematical modelling tool to predict the physicochemical properties of the fuel [19,20]. Later the data found in the lab and the predictions results obtained by the model were compared.…”

“…Choudhry et al [19] has reported experimentally verified gasoline fuel surrogate design using a computer aided model-based technique MINLP. In a different study Choudhury et al [20] have used the computer aided modelling tool to screen additive quickly and later experimentally validated the predictive ability of the computer model. The chemical properties and property models were called to solve the problem by producing a number of suitable candidates, which in their turn were calculated by a rigorous model and verified by experimental tests.…”

“…Although there are voluminous literature available on predictive model development for designing fuel blends, no attempts were made to include the impact of the lubricity additives on the fuels physicochemical property to the best of our knowledge. In our earlier publications we have successfully developed a computer based model which can predict the physicochemical properties of the fuel and fuel blends [19,20]. Advancing the model to incorporate a comprehensive view on the effect of the lubricity additives on all critical properties allows the flexibility to explore different blend compositions without the need of physical formulation in the laboratory.…”

REDIFUEL: Robust and efficient processes and technologies for drop-in renewable fuels for road transport

“…Successively, the phisico-chemical properties of RFA30P70 are exchanged with the one of diesel fuel. The liquid properties of the renewable fuel are estimated using different models available in the literature [Viswanath, Dabir S., et al, 2007 andYaws, Carl L, 2008] and considering 1-octanol as surrogate for the alcoholic share, a mixture of cyclooctane (45 vol%), isocetane (51 vol%) and n-decane (4 vol%) as surrogate for GtL [Choudhury, H. A., et al, 2017], and DF-2 [Farrell, J. T., et al, 2007] for diesel fuel for the liquid phase. The gas-phase properties of the alcoholic components are modelled with 1-octanol, due to the very close ICN as shown in Figure 4.…”