CN-122010671-A - Propane dehydrogenation method capable of stabilizing sulfur concentration

Abstract

The invention belongs to the technical field of petrochemical industry, and discloses a propane dehydrogenation method for stabilizing sulfur concentration, wherein a vulcanizing agent is added into a bubbler, the bubbler is arranged in a circulating cooler, a circulating constant-temperature water bath is adjusted to reach a preset temperature T1, an inlet of the bubbler is connected with a preset gas G1, an outlet of the bubbler is connected with a propane dehydrogenation reactor, a pre-reduced platinum-containing catalyst is added into the propane dehydrogenation reactor, after the propane dehydrogenation reactor is heated to the preset temperature T2, the flow of the preset gas G1 is set to be a preset flow F1, and reaction gas is introduced into the propane dehydrogenation reactor, so that the sulfur concentration of an effluent section of the reactor is stabilized at the preset concentration until the reaction is finished. According to the invention, the sulfur content of ppm level is stably maintained in the reaction atmosphere by adopting a vulcanizing agent saturated steam sample injection mode at a specific temperature, so that the metal material on the wall surface of the reaction tube is passivated, the cracking and deep dehydrogenation of propane on the metal material are inhibited to generate coke, and the improvement of propylene selectivity and reaction stability is realized.

Inventors

• GONG JINLONG
• LU ZHENPU
• HUANG YIPING
• PEI CHUNLEI
• YUE CHANGHAI
• CHEN SAI
• WEI ZHENHAO
• CAI XINLEI

Assignees

• 中建安装集团有限公司
• 天津大学

Dates

Publication Date

20260512

Application Date

20251230

Claims (10)

1. 1. A process for the dehydrogenation of propane to stabilize sulfur concentration comprising: (1) Adding a vulcanizing agent into a bubbler, placing the bubbler into a circulating cooler, and adjusting a circulating constant-temperature water bath to a preset temperature T1; (2) The inlet of the bubbler is connected with a preset gas G1, and the outlet of the bubbler is connected with the inlet of the propane dehydrogenation reactor; (3) Adding a pre-reduced platinum-containing catalyst into the propane dehydrogenation reactor; (4) After the propane dehydrogenation reactor is heated to a preset temperature T2, the flow of preset gas G1 is set to be a preset flow F1, and reaction gas is introduced into the propane dehydrogenation reactor, so that the sulfur concentration of the effluent section of the reactor is stabilized at a preset concentration until the reaction is finished.
2. 2. The method for dehydrogenating propane with stable sulfur concentration according to claim 1, wherein the preset temperature T1 in step (1) and the preset flow rate F1 in step (4) are calculated from the saturation vapor pressure of the sulfiding agent according to the preset concentration in the propane dehydrogenation reactor.
3. 3. A method for dehydrogenating propane with a stable sulfur concentration according to claim 1, wherein the sulfiding agent in step (1) is dimethyl disulfide.
4. 4. The method for dehydrogenating propane with stable sulfur concentration according to claim 1, wherein the predetermined gas G1 in the step (2) is hydrogen or nitrogen.
5. 5. The method for dehydrogenating propane with stable sulfur concentration according to claim 1, wherein the platinum catalyst in the step (3) is a platinum-containing catalyst supported on alumina.
6. 6. A propane dehydrogenation process according to claim 1, characterized in that the mass fraction of platinum in the platinum catalyst in step (3) is 0.1-2.0%.
7. 7. A propane dehydrogenation process with stable sulfur concentration according to claim 1, characterized in that the preset temperature T2 in step (4) is 550-620 ℃.
8. 8. A method for dehydrogenating propane with a stable sulfur concentration according to claim 1, wherein the reaction gas in step (4) contains propane.
9. 9. A propane dehydrogenation process according to claim 1, characterized in that the preset concentration of sulfur concentration in step (4) is 10-1000ppm in terms of the amount of substance.
10. 10. The method for dehydrogenating propane with stable sulfur concentration according to claim 1, wherein the preset gas G1 in the step (4) is continuously introduced into the propane dehydrogenation reactor during the whole reaction process, and the flow is maintained to be stable for a preset flow F1.

Description

Propane dehydrogenation method capable of stabilizing sulfur concentration Technical Field The invention belongs to the technical field of petrochemical industry, and particularly relates to a propane dehydrogenation method capable of stabilizing sulfur concentration. Background The dehydrogenation of propane to propylene (Propane Dehydrogenation, PDH) is an important industrial process for the conversion of propane to propylene. Propylene is an important raw material in the chemical industry and is used for producing various chemical products such as polypropylene, epoxy resin, acrylic acid and esters thereof. With the global growing demand for propylene, propane dehydrogenation technology is becoming increasingly interesting. The advantage of propane dehydrogenation technology is that it is widely available and relatively low cost, and particularly after shale gas revolution, propane is available in sufficient and inexpensive form. In addition, the technology can reduce the dependence on petroleum resources and provide a more environment-friendly production path. With the continuous progress of technology, the dehydrogenation of propane to propylene has become one of the important sources of propylene in modern chemical production. Pt-based catalysts are a class of catalysts with high activity for the dehydrogenation of propane to propylene, and are the focus of current research. However, during the propane dehydrogenation reactor, the temperature of which can be up to 600 ℃ or more, cracking of propane in the metal reaction tube may cause carbon deposition problems, which may reduce the reaction efficiency. At the same time, carbon deposition may cause partial or complete blockage of the reactor tube, increasing system pressure drop, affecting flowability and process control. In addition, carbon deposition can also lead to catalyst poisoning, covering the catalyst surface, reducing its activity and selectivity. Excessive carbon deposition can even cause thermal stress concentrations, resulting in mechanical damage or deformation of the metal reaction tube. This problem can be ameliorated by injecting a sulfiding agent into the large reactor to maintain a ppm level sulfur-containing atmosphere in the reaction atmosphere. However, since the gas flow rate of the small reactor is small, if the sulfur content of ppm level is to be maintained, the injection amount of the vulcanizing agent needs to be maintained at about 1×10 −3 μl/min, and it is difficult to achieve the required accuracy with the conventional syringe pump and other devices. Disclosure of Invention The invention focuses on how to effectively inhibit the technical problem of catalyst carbon deposition through a vulcanizing agent in a small propane dehydrogenation reactor, and provides a propane dehydrogenation method with stable sulfur concentration. In order to solve the technical problems, the invention is realized by the following technical scheme: The invention provides a propane dehydrogenation method with stable sulfur concentration, which comprises the following steps: (1) Adding a vulcanizing agent into a bubbler, placing the bubbler into a circulating cooler, and adjusting a circulating constant-temperature water bath to a preset temperature T1; (2) The inlet of the bubbler is connected with a preset gas G1, and the outlet of the bubbler is connected with the inlet of the propane dehydrogenation reactor; (3) Adding a pre-reduced platinum-containing catalyst into the propane dehydrogenation reactor; (4) After the propane dehydrogenation reactor is heated to a preset temperature T2, the flow of preset gas G1 is set to be a preset flow F1, and reaction gas is introduced into the propane dehydrogenation reactor, so that the sulfur concentration of the effluent section of the reactor is stabilized at a preset concentration until the reaction is finished. Further, the preset temperature T1 in the step (1) and the preset flow F1 in the step (4) are calculated according to the preset concentration in the propane dehydrogenation reactor by the saturated vapor pressure of the vulcanizing agent. Specific: Firstly, determining the saturated vapor pressure P s of the selected vulcanizing agent at a preset temperature T1 by utilizing an Artwan equation according to the physical property of the selected vulcanizing agent, wherein P s is the saturated vapor pressure; Secondly, calculating the mole fraction (P s /Psys) of the vulcanizing agent saturated and carried in the carrier gas (passing through with a preset flow F1) at a preset temperature T1 and a system pressure P sys according to the Dalton partial pressure law and an ideal gas state equation; And finally, converting the preset flow F1 (the mass flow of the gas entering the bubbling gas) into the actual supply quantity of the vulcanizing agent by combining the ratio of the relative molecular mass of the vulcanizing agent and the carrier gas, so that the material balance requirement of the pres