CN-122010050-A - Method for preparing hydrogen-rich gas by directional catalytic pyrolysis of oil-containing sludge

CN122010050ACN 122010050 ACN122010050 ACN 122010050ACN-122010050-A

Abstract

The invention belongs to the technical field of oil-containing sludge recycling and hydrogen-rich gas preparation, and particularly discloses a method for preparing hydrogen-rich gas by directional catalytic pyrolysis of oil-containing sludge, which comprises the following steps of S1, pretreatment of oil-containing sludge, drying and crushing treatment; S2, pyrolysis of oil-containing sludge, namely introducing inert atmosphere and heating to 650-700 ℃, S3, in-situ catalysis and long-residence directional conversion, namely fully contacting pyrolysis gas with CaO catalyst in situ at the temperature of 650-700 ℃, S4, collecting hydrogen-rich gas, and S5, product separation and catalyst regeneration treatment, namely adopting a membrane separation method or a PSA pressure swing adsorption method. The method for preparing the hydrogen-rich gas by the directional catalytic pyrolysis of the oily sludge improves the yield of the pyrolysis gas and the hydrogen ratio, reduces the carbon dioxide emission, and realizes the efficient directional conversion of the oily sludge to the hydrogen-rich gas.

Inventors

HU HAIJIE
LI JINLING
HAN LEI
YANG BO
QU CHENGDUN
YU TAO
LIU JIAXUAN
JIA SHANSHAN

Assignees

西安石油大学

Dates

Publication Date: 20260512
Application Date: 20260309

Claims (8)

1. The method for preparing the hydrogen-rich gas by directional catalytic pyrolysis of the oil-containing sludge is characterized by comprising the following steps of: S1, pretreatment of oily sludge, namely drying and crushing the oily sludge, wherein the water content of the pretreated oily sludge is controlled to be less than or equal to 30%, the particle size is controlled to be less than or equal to 5mm, and the variation coefficient of the mixing uniformity is controlled to be less than or equal to 10%; S2, pyrolyzing the oily sludge, namely, sending the pretreated oily sludge into an integrated pyrolysis catalytic reactor, introducing inert atmosphere, heating to 650-700 ℃, and maintaining the temperature for pyrolysis reaction to generate pyrolysis gas, pyrolysis oil and pyrolysis carbon; s3, in-situ catalysis and long-residence directional conversion, namely, a CaO catalyst layer is arranged in the integrated pyrolysis catalytic reactor, the residence time of pyrolysis gas is controlled to be 1.5h, and the pyrolysis gas and the CaO catalyst are fully contacted in situ at the temperature of 650-700 ℃ to generate catalytic conversion reaction; s4, collecting the hydrogen-rich gas, namely collecting the converted hydrogen-rich gas through a hydrogen-rich gas collecting unit; s5, separating and purifying the hydrogen-rich gas by a membrane separation method or a PSA pressure swing adsorption method to obtain hydrogen and methane respectively.
2. The method for preparing hydrogen-rich gas by directional catalytic pyrolysis of oily sludge according to claim 1, wherein in S2, the inert atmosphere is nitrogen or argon with the purity of more than or equal to 99.9%, and the inlet flow is 5-20 m 3 /h.
3. The method for preparing hydrogen-rich gas by directional catalytic pyrolysis of oily sludge according to claim 1, wherein in S3, the catalyst particle size of the CaO catalyst layer is 1-10 mm, the specific surface area is 30-200 m 2 /g, the mass ratio of the CaO catalyst to the oily sludge is 0.5-2:1, and the CaO catalyst layer adopts a honeycomb structure.
4. The method for preparing hydrogen-rich gas by directional catalytic pyrolysis of oily sludge according to claim 1, wherein in S2, the temperature rising rate is 5-10 ℃ per minute.
5. The process for preparing hydrogen-rich gas by directional catalytic pyrolysis of oil-containing sludge of claim 1, wherein in S2 the pyrolysis gas comprises hydrogen, methane, carbon dioxide, carbon monoxide, C2-C3 hydrocarbons and tar vapor.
6. The method for preparing hydrogen-rich gas by directional catalytic pyrolysis of oil-containing sludge as claimed in claim 1, wherein in S4, the hydrogen-rich gas comprises the following components in percentage by volume: 30-31% of hydrogen, 41-43% of methane, 4-4.5% of carbon dioxide, 17-19% of carbon monoxide and 4-6% of C2-C3 hydrocarbons; the hydrogen-rich gas accounts for 24% of the total distribution of the pyrolysis products.
7. The method for preparing hydrogen-rich gas by directional catalytic pyrolysis of oily sludge according to claim 1, wherein after S5, the method further comprises a regeneration treatment of CaO catalyst, specifically: Air is used as a regeneration medium, the regeneration temperature is 600-800 ℃, the regeneration time is 2-4 hours, and the recovery rate of catalytic activity after regeneration is more than or equal to 90%.
8. The method for preparing hydrogen-rich gas by directional catalytic pyrolysis of oily sludge according to claim 1, wherein in S2, the integrated pyrolysis catalytic reactor is provided with a heat accumulating radiant tube, a spiral guide plate, a buffer cavity and a second-layer circulating unit, the heat accumulating radiant tube is used for precisely controlling temperature, the spiral guide plate is used for guiding pyrolysis gas to flow directionally, the buffer cavity is used for balancing airflow, and the second-layer circulating unit is used for regeneration and circulating catalysis of CaO catalyst.

Description

Method for preparing hydrogen-rich gas by directional catalytic pyrolysis of oil-containing sludge Technical Field The invention relates to the technical field of oil-containing sludge recycling and hydrogen-rich gas preparation, in particular to a method for preparing hydrogen-rich gas by directional catalytic pyrolysis of oil-containing sludge. Background The oily sludge is a large amount of industrial waste produced in industries such as petrochemical industry, oil refining, steel and the like, has complex components, mainly contains oil, water, solid particles, heavy metals, polycyclic aromatic hydrocarbon and other harmful substances, seriously pollutes soil, water and atmospheric environment if the oily sludge is improperly treated, threatens ecological safety and human health, and is a difficult problem to be solved urgently in the industries for harmless treatment and recycling. The traditional oily sludge treatment technology such as landfill, incineration, biodegradation and the like has the defects of resource waste, secondary pollution or long treatment period and the like, and is difficult to meet the green development requirement. The oil-containing sludge is recycled, so that on one hand, additional economic value can be obtained through recycling treatment, and on the other hand, the secondary environmental pollution of the sludge can be avoided. The hydrogen-rich gas (mainly hydrogen and methane) is used as a clean and efficient energy carrier, and has wide application in the fields of industrial fuel, chemical synthesis, hydrogen energy application and the like. The low-carbon economy and cyclic utilization of the oil-containing sludge can be realized to the greatest extent by converting the oil-containing sludge into hydrogen energy. In the prior art, most of oil-containing sludge pyrolysis gasification technologies are single pyrolysis technologies, the pyrolysis temperature is low and effective catalytic regulation is lacking, so that the distribution of products is unreasonable, pyrolysis gas in conventional pyrolysis products is only 15%, pyrolysis oil is 17%, pyrolysis carbon is 68%, hydrogen in gas products is only 15%, carbon dioxide is up to 19%, meanwhile, the retention time of the pyrolysis gas is short, the conversion is insufficient, and the proportion of heavy hydrocarbon components such as C2-C3 is up to 24%, so that the energy utilization efficiency is reduced, and the environmental protection pressure is increased. In addition, some technologies attempt to introduce catalytic means, but most of the technologies are externally connected with catalytic devices, so that the problems of condensation loss, insufficient contact with a catalyst and the like in the pyrolysis gas transmission process exist, and in-situ efficient conversion cannot be realized. Therefore, an in-situ catalysis and long-residence regulation-based directional pyrolysis technology for the oily sludge is developed, the yield and the hydrogen selectivity of hydrogen-rich gas are improved, and the carbon dioxide emission is reduced, so that the method has important practical significance and application value. Disclosure of Invention The invention aims to provide a method for preparing hydrogen-rich gas by directional catalytic pyrolysis of oily sludge, which improves the yield of pyrolysis gas and the hydrogen ratio, reduces the carbon dioxide emission and realizes the efficient directional conversion of the oily sludge to the hydrogen-rich gas. In order to achieve the above purpose, the invention provides a method for preparing hydrogen-rich gas by directional catalytic pyrolysis of oil-containing sludge, which comprises the following steps: S1, pretreatment of oily sludge, namely drying and crushing the oily sludge, wherein the water content of the pretreated oily sludge is controlled to be less than or equal to 30%, the particle size is controlled to be less than or equal to 5mm, and the variation coefficient of the mixing uniformity is controlled to be less than or equal to 10%; S2, pyrolyzing the oily sludge, namely, sending the pretreated oily sludge into an integrated pyrolysis catalytic reactor, introducing inert atmosphere, heating to 650-700 ℃, and maintaining the temperature for pyrolysis reaction to generate pyrolysis gas, pyrolysis oil and pyrolysis carbon; s3, in-situ catalysis and long-residence directional conversion, namely, a CaO catalyst layer is arranged in the integrated pyrolysis catalytic reactor, the residence time of pyrolysis gas is controlled to be 1.5h, and the pyrolysis gas and the CaO catalyst are fully contacted in situ at the temperature of 650-700 ℃ to generate catalytic conversion reaction; s4, collecting the hydrogen-rich gas, namely collecting the converted hydrogen-rich gas through a hydrogen-rich gas collecting unit; s5, separating and purifying the hydrogen-rich gas by a membrane separation method or a PSA pressure swing adsorption method to obtain hydrogen and methan