Rapid determination of methanol content in methanol gasoline_Industrial additives

Background and overview^[1]

Methanol is a simple alcohol used as a reagent in many manufacturing processes and as a fuel. As a substitute for ordinary gasoline, methanol gasoline is a way of “replacing oil with coal” and can directly replace ordinary gasoline. While alleviating the tight supply of gasoline, it has good environmental benefits and is beneficial to the sustainable development of the country’s ecological economy and Social progress is of great significance.

Methanol gasoline is a mixture of methanol, gasoline and additives. The methanol blending amount is generally 5% to 30%. Those with the highest blending rate of 15% are called M15 methanol gasoline. The calorific value of methanol is about half that of gasoline. Without changing the compression ratio of the car engine, the methanol content must be fixed within a certain range. If the content is too low, the octane number will be too low and damage the engine; if the content is too high, the calorific value of the fuel will be insufficient, increasing fuel consumption and cost. At the end of 2009, my country officially promulgated the product standard for high-proportion methanol gasoline for vehicles, “Methanol Gasoline for Vehicles (M85)”, which requires that the content of methanol in methanol gasoline is about 85%. Shaanxi Province has fully promoted the use of M15 methanol gasoline. Among the national standards (M85) and local standards of various provinces, such as Hebei Province local standards “M30 Methanol Gasoline for Vehicles”, “Methanol Gasoline Component Oil for Vehicles”, Shanxi Province Local Standard DB14/T 92-2002, Zhejiang Province Local Standards Standards such as DB33/T 756.2-2009 have strict requirements on the methanol content in methanol gasoline.

Rapid determination of methanol content in methanol gasoline^[2]

CN201210039272.3 provides a method for rapid determination of methanol content in methanol gasoline based on Raman spectrum superposition. The method is simple and effective. The object of the present invention is achieved through the following technical solution: a rapid determination method for methanol gasoline methanol content based on the linear superposition principle of Raman spectrum. The method includes the following steps:

(1) Add methanol to a certain base oil and prepare methanol gasoline with any volume content; use a Raman spectrometer to measure the Raman spectra of the base oil, the above-mentioned methanol gasoline and pure methanol; first, conduct the obtained spectrum Preprocessing such as smoothing, noise filtering, and fluorescence background removal; then normalizing the saturated hydrocarbon characteristic peaks of the base oil and methanol gasoline spectra to obtain spectrum A and spectrum B; performing maximum value normalization on the pure methanol spectrum to obtain the spectrum C; The base oil refers to methanol-free conventional gasoline mixed with catalytic gasoline, reformed gasoline and MTBE.

(2) Represent spectrum B as the weighted algebraic sum of base oil spectrum A and pure methanol spectrum C, and establish the linear superposition formula of the spectrum corresponding to the base oil:

B=k1[(1-m)A]+k2(mC) +E;

In the formula, m is the volume percentage concentration of methanol in methanol gasoline, E is the spectrum measurement error, k1=a, k2=aK, a is the system parameter, K is the relative Raman intensity of methanol in methanol gasoline,

Then use the least squares method to obtain k1 and k2. Using K=k2/k1, the key parameter K in the spectral linear superposition formula can be obtained. Finally, the spectrum A and parameter K are stored in the spectrum database;

(3) Select different base oils and repeat steps 1 and 2. From this, the spectral linear superposition formulas corresponding to different base oils can be established, as well as a spectral database containing the spectra of various base oils and their parameters K;

(4) For the oil sample to be tested with unknown base oil type and unknown methanol content, use a Raman spectrometer to measure its spectrum; first perform preprocessing on the spectrum such as smoothing, noise filtering, and fluorescence background removal, and then Saturated hydrocarbons are normalized to obtain spectrum D;

(5) Select different base oil spectra A and their related parameters K from the spectrum database, and use the spectral superposition formula, D=k3A+k4KC+E, where k3=a(1-m), k4=am use The least squares method is used to estimate k3 and k4; the coefficients k3 and k4 with the smallest estimation error in all cases are selected as the final estimation coefficients, and k3 and k4 are used to calculate m, thus obtaining the methanol content in the methanol gasoline sample.

The beneficial effects of the present invention are that the method for rapid determination of methanol content in methanol gasoline based on the linear superposition principle of Raman spectrum has fast measurement speed, high analysis accuracy, and greatly reduces the required calibration samples, which provides a basis for the promotion of methanol gasoline in my country. A convenient detection method is provided in the process.

Method of converting to diesel^[1]

Prepare an adhesive with an aluminum sol with a density of 0.7g/ml and a nitric acid aqueous solution with a concentration of 5% (the volume ratio of the aluminum sol to the nitric acid aqueous solution is 15:1). Grind and mix the cobalt oxide and the nitric acid aqueous solution evenly. Powder of aluminum (Co:Al=1:9 molar ratio) is poured into the A pelletizing machine, contacted with the atomized and sprayed adhesive, and rolled into shape. When the radius of the formed pellets reaches 2.5mm, the pellets are formed from After being rolled out of the pelletizing machine A, it enters the pelletizing machine B. The pelletizing machine B contains uniformly ground and mixed powders of copper oxide, zinc oxide and aluminum oxide (Cu:Zn:Al=1:1:6 molar ratio) , under the action of the atomized and sprayed adhesive, continue rolling and forming to a spherical shape with a diameter of 10mm, and leave the B ball machine. At this time, the active components with Fischer-Tropsch synthesis function are distributed in the core area with a radius of ≤2.5mm, while the active components with methanolysis function are distributed in the outer shell area with a radius between 2.5mm and 5mm. After the shaped spherical particles were calcined at ℃ for 2 hours, spherical catalyst particles were obtained. Such catalyst particles are loaded into a fixed bed reactor with an inner diameter of 80 mm to form a catalyst bed with a height of 320 mm. At the initial moment, the air velocity is 1000h^-1Pour synthesis gas (H₂:CO=2 volume ratio) into the reactor, and increase the flow rate from zero at a rate of 10% per hour. The proportion of methanol in the feed (the total feed amount is measured by the total moles of methanol and synthesis gas, the proportion of methanol in the total feed is the mole percentage of methanol in the total feed), after 10 hours the feed will all be methanol, Under reaction conditions of 225°C and 5MPa, when reacting for 24 hours, the methanol conversion rate was 30%, CO2 accounted for 28% of the total products, and among the hydrocarbon products, the methane selectivity was 12%, while C10 and above (herein referred to as C10 and above) The component represents diesel, the same below) with a selectivity of 51%.

References

[1] [China invention, China invention authorization] CN201410451845.2 A method of converting methanol into diesel oil

[2] [Invented in China, authorized by China] CN201210039272.3 Rapid determination method of methanol content in methanol gasoline based on Raman spectrum superposition