Patent FR-2815413-A1 (FR)
Title: Determination of characteristics of distillation of liquid petroleum products, comprises distilling small sample with continuous measurements of temperatures and pressures in liquid and vapor phases
Inventor: ABAEV GUENRIKH
IPC: B01D3/14
Filed: 2000-10-17
Abstract: To determine the characteristics of the distillation of liquid petroleum products, using a rapid mini-distillation, a sample of 5-15 ml is heated in a distillation flask (1) at a constant and controlled heat. Continuous temperature measurements are taken of the sample during distillation of the liquid and the vapor phases by thermal sensors (5,6). The vapor pressure is measured (7). The temperature and pressure signals are evaluated (14).  To determine the characteristics of the distillation products using a small sample of liquid petroleum, in a rapid distillation action, it is heated at a constant level according to the nature of the sample to measure the progress towards the boiling point. The vapor pressure is monitored constantly at the entry (40) into the escape tube (4), together with the temperatures of the liquid phase (TL) and the vapor phase (TS) to give curves of the pressure/temperature changes as a function of time ( tau 1) to give curves for establishing the boiling point of the liquid phase (TLIBP). The temperature at the boiling point into the vapor phase (TSIBP) shows at an increase in pressure. The temperature (TLEND) of the actual liquid phase temperature is equal to the temperature (TSFBP) at the end of boiling in the vapor phase. The vol.% of the distilled sample (Vv) is shown in the curve of vapor pressure (P) variations as a function of time ( tau 1) in the distillation flask and the actual temperature of the sample vapor phase is determined by the function where (Sf(TS,P) depend on the surface under the pressure diagram in the distillation process, and Sf(TiS,P) represents the fraction of that surface by time ( tau 1i), Vires) is the volume of liquid in the distillation flask by time ( tau 1i). The molecular percentage of the distilled sample (VM) is a function of the actual temperature of the sample in the vapor phase (TS) by the function VMi=f(Vvi, Pi,TSi) where  rho i is the molecular density by time ( tau 1i). The temperature at the end of boiling in the liquid phase (TLFBP) is determined by iteration using the formula where VEND is the molecular percentage of the distilled sample at the temperature TLEND, while a and k are coefficients of the mathematical distillation model according to the empirical formula calculated by iteration using the equation where in calculating at each step a new value of TLFBP at the moment where TL(n)FBP-TL(n-1)FBP\=1oC. The molecular percentage of the distilled sample is recalculated as a function of the actual sample temperature value in the vapor phase to take into account the distillation residues and losses by the formula VMi=v'Mi+\=DLi+\=DSi where  DELTA Si is the percentage of the vapor phase during distillation,  DELTA Li the percentage of the liquid phase as it is formed by condensation, and VMi the molecular percentage of the distilled sample taking the residues into account. The vol.% of the distilled sample (VVi is determined as a function of the actual temperature of the sample in the liquid phase by the formula: VVi=f(VMi,  rho i; TiL) to form an appropriate curve. The intensity of the heat is controlled at the heater (2) to give a distillation time of 5-15 mins. The empirical value of the sample in the vapor phase (TSTAND) matches a standard norm from the sample temperature in the liquid phase (TL) using the formula TiSTAND=TLi-\=hi where  eta  is a function of the temperature difference. TD86STAND is the empirical temperature defined by ASTM D 86 and  eta D86 is calculated by the function and is determined graphically using the parameter values (a,k,TLIBP,TLFBP). An Independent claim is included to determine the characteristics of the distilled products of a heavy liquid petroleum with a boiling point \- 400 deg C, where the petroleum sample selected is a light liquid petrol with a boiling point of  <= 3 00 deg C, compatible with the sample for analysis. A curve is produced to show the molecular percentage (VM) as a function of the actual temperature in the liquid phase TLVMi(porteur)=f(TiL). Preferred Features: A mixture is prepared containing 85-95% of the light material and 5-15% of the sample for analysis, so that at least 90% of the mixture has a boiling point  <=  360 deg C. The mixture is processed to give curves showing the molecular percentage (VM) of the distilled mixture as a function of the mixture temperature (TL) in the liquid phase (VMi(mix)=f(TiL) in the same coordinate system as for the light distillation. The temperature of the analysis sample at the end of boiling (TFBPHP) is equal to the temperature of the mixture at the end of boiling in the liquid phase TFBPHP=TLFBP(mix), where TLFBP is set by iteration. The temperature of the sample for analysis in the liquid phase, at the start of boiling (TIBPHP) is calculated by the formula where Ti is the intersection temperature of the curves VMi(porteur)=f(TiL) and VMi(mix)=f(TiL). VMi is the molecular percentage of the sample which matches the temperature T1 and  DELTA T1=TFBPHP-T1. aHP and kHP are determined by the use of additive equations: and where Si(T) and Si( tau ) are functions of the surfaces under the distillation curves in the coordinate systems VM, T and Vm.  tau  and  EPSILON  are functions of the specific gravity of the light component in the mixture, and the curves (VMHP=f(T) are traced using the formula: The light petroleum product is kerosene and/or a liquid petroleum product with a boiling point   <= 300 deg C. From the normal distillation curves (LBP VM=f(T)) for a column with a single level, the curves of the actual boiling points (TBP) match a technique with a column of at least 15 theoretical levels, to take the temperatures TLEND(LBP) and TLEND(TBP) as equal. The normal (LBP) coordinate systems VM, T are taken as equal to the actual boiling point curves, and TIBP(TBP)=f(SLBP), f(SLBP) according to the surface under the normal distillation curve.