Method for activating benzene-method maleic anhydride catalyst outside reactor

Abstract

The invention discloses a method for activating a benzene-method maleic anhydride catalyst outside a reactor. The method comprises the following steps: 1, placing the benzene-method maleic anhydride catalyst in the activation reactor; 2, introducing air into the activation reactor, so that the interior of the activation reactor is filled with air; 3, raising the temperature of the benzene-method maleic anhydride catalyst, wherein the temperature-raising gradient is 60-100 DEG C / h, after the temperature is raised to 300 DEG C, changing the temperature-raising gradient to 0-80 DEG C / h, and raising the temperature to 440-460 DEG C; 4, after the temperature is preserved for 3-5 hours, lowering the temperature to 420-440 DEG C, introducing ammonia gas, when the volume ratio of ammonia gas to air in the activation reactor reaches 1 / 25 to 1 / 15, stopping gas introduction, and continuing preserving the temperature for 2-4 hours, then lowering the temperature to the room temperature, wherein the temperature lowering time is one hour, so that the benzene-method maleic anhydride catalyst activated outside the reactor is obtained. According to the method, air and a gas mixture of ammonia gas and air are adopted as activation atmosphere in sequence, activation cost is lowered, stability of catalyst activity is guaranteed, and stability of the benzene conversion rate is greatly improved.

Description

technical field [0001] The invention relates to the technical field of catalysts, in particular to an external activation method of a benzene-process maleic anhydride catalyst. Background technique [0002] The production of maleic anhydride by gas-phase fixed-bed catalytic oxidation of benzene as raw material has a history of decades at home and abroad. Although the production of maleic anhydride by n-butane oxidation will replace the traditional production process of maleic anhydride by benzene oxidation in the world, due to resource Depending on the quantity and price, the benzene oxidation production process will continue to exist for a long time in many countries and regions, and will still have certain market competitiveness. At present, the production of benzene in my country has exceeded 1400Kt / a, while the production of maleic anhydride by benzene oxidation only accounts for about 6% of the total consumption of benzene. The supply of raw materials is abundant and th...

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Problems solved by technology

[0004] In 2010, a patent with the authorized announcement number CN102371187B disclosed an external activation method of maleic anhydride catalyst. In the catalyst activation method provided in this patent, the activation atmosphere is under closed conditions, and the activation is adjusted by self-decomposing gas atmosphere, to achieve the activation effect, but when the catalysts with different active components are activated, or the ratio of the active components of the catalyst is different, the concentration of various substances in the activation atmosphere is uncontrollable, which will lead to insufficient stability of the catalyst activity to a certain extent, affecting the The next step is to use it uniformly

At the same time, when the active catalyst obtained by this technology is used for benzene oxidation to produce maleic anhydride, the benzene conversion rate varies in a large range, which may be related to the insufficient stability of the catalyst activity.

[0005] In 2005, our company applied for a patent with the publication number CN1579631A, which belongs to the activation method outside the device. The method proposed in this patent is to use ammonia-containing air for activation in the whole process, and the ammonia-to-air ratio needs to be controlled at 1:25~ 1:5, but because of the addition of ammonia, ammonia is used to adjust the activation atmosphere, which increases the input cost to a certain extent

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