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CN-122012125-A - Coupling method for oil-containing sludge oil gas recovery and biochar preparation

CN122012125ACN 122012125 ACN122012125 ACN 122012125ACN-122012125-A

Abstract

The invention discloses a coupling method for oil gas recovery of oily sludge and biochar preparation, which belongs to the technical field of recycling of the oily sludge, and specifically comprises the steps of compounding the oily sludge with biomass waste to form a composite raw material with a clay-carbon precursor structure; and then carrying out programmed temperature-controlled coupling pyrolysis under an inert atmosphere, firstly carrying out slow pyrolysis in a first temperature region of 200-400 ℃ to fully recover oil gas, and then carrying out heat preservation in a second temperature region of 500-700 ℃ to promote the framework structure of clay minerals and biomass carbon to form stable biochar. The coupling method for oil-containing sludge oil gas recovery and biochar preparation can synchronously realize the improvement of the light yield of oil gas products and the in-situ conversion of pyrolysis residues into high-performance biochar. The method does not need exogenous additives and subsequent modification, has simple process and low cost, and realizes comprehensive recycling and high-value utilization of the oil-containing sludge.

Inventors

  • HU HAIJIE
  • YANG BO
  • JIA SHANSHAN
  • HAN LEI
  • LI JINLING
  • QU CHENGDUN

Assignees

  • 西安石油大学

Dates

Publication Date
20260512
Application Date
20260312

Claims (10)

  1. 1. The coupling method for oil-containing sludge oil gas recovery and biochar preparation is characterized by comprising the following steps: (1) Raw material construction, namely compounding oily sludge and biomass waste to form a composite raw material with a clay-carbon precursor structure; the oil content of the oil-containing sludge in the composite raw material obtained after the compounding is 15% -40%, the content of the natural clay mineral is 10% -30%, and the water content is 50% -60%; The biomass waste is an agricultural or forestry processing byproduct, and the addition amount of the biomass waste accounts for 5% -25% of the total mass of the composite raw material; (2) Performing coupling pyrolysis, namely placing the composite raw materials in inert atmosphere, and performing program temperature control coupling pyrolysis; Carrying out slow pyrolysis in a first temperature zone of 200-400 ℃ at a heating rate of 3-5 ℃ per minute, and preserving heat for 60-90 minutes at the tail end of the temperature zone; Heating to a second temperature region of 500-700 ℃, raising the heating rate to 10-20 ℃ per minute, and preserving heat for 60-120 minutes; (3) And outputting products, namely respectively collecting and condensing oil gas products generated in the first temperature zone and the second temperature zone, and collecting solid biochar obtained after the second temperature zone is finished.
  2. 2. The coupling method for oil gas recovery and biochar preparation of the oil-containing sludge according to claim 1 is characterized in that in the step (1), the oil-containing sludge is a mixture of crude oil and crude oil product storage tank bottom sediment, ground oil sludge and dehydrated oil-containing scum, wherein the oil content of the crude oil and crude oil product storage tank bottom sediment is 30% -60%, the water content is 20% -40%, the solid content is 3% -6%, the oil content of the ground oil sludge is 5% -15%, the natural clay mineral content is 30% -70%, the water content is 30% -50%, the oil content of the dehydrated oil-containing scum is 8% -10%, the water content is 75% -80% and the solid content is 6% -8%.
  3. 3. The coupling method for oil-containing sludge oil gas recovery and biochar preparation according to claim 1, wherein in the step (1), the natural clay mineral is montmorillonite or bentonite with a layered structure, and the biomass waste is at least one selected from straw, wood chips, rice hulls and coconut shells.
  4. 4. The method for coupling oil-containing sludge oil-gas recovery and biochar preparation according to claim 1, wherein in the step (2), the heating rate of the first temperature zone is set according to the total volatile content of the composite raw materials, and the heating rate is correspondingly reduced by 1 ℃ per minute every 5% of the total volatile content.
  5. 5. The coupling method for oil gas recovery and biochar preparation of the oily sludge according to claim 1, wherein in the step (2), the end point temperature of the second temperature zone is set according to the application requirement of the target biochar, wherein the end point temperature is controlled to be 600-700 ℃ when the method is used for acid soil improvement, and the end point temperature is controlled to be 500-600 ℃ when the method is used for water body adsorption.
  6. 6. The method for coupling oil and gas recovery of oily sludge and biochar production according to claim 1, wherein in the step (2), the inert atmosphere is nitrogen.
  7. 7. The coupling method for oil gas recovery and biochar preparation of the oily sludge according to claim 1, wherein in the step (1), the proportion of the composite raw materials is required to satisfy the following relation of 0.15- Raw materials / ‌ω clay ‌ (O/C) to 0.30, wherein (O/C) Raw materials is the atomic ratio of oxygen and carbon elements of the composite raw materials, and ‌ omega clay is the mass percentage of clay minerals in the composite raw materials.
  8. 8. The coupling method for oil gas recovery and biochar preparation of the oily sludge according to claim 1, wherein the end temperature T of the second temperature zone and the pH value of the obtained biochar follow the following empirical relationship of pH=0.0115+2.4, wherein the value of T ranges from 500 ℃ to 700 ℃.
  9. 9. The coupling method for oil-containing sludge oil gas recovery and biochar preparation according to claim 1, wherein the heat preservation time t of the second temperature zone and the biomass addition amount B in the composite raw material meet the function relation of t=alpha×B, wherein alpha is a proportionality coefficient, and the value range is 1.8-2.2 min/wt%.
  10. 10. The coupling method for oil gas recovery of oily sludge and preparation of biochar, which is characterized in that the prepared biochar has a multi-stage pore structure formed by in-situ crosslinking interpenetrating of clay mineral frameworks derived from the oily sludge and carbon frameworks derived from biomass through pyrolysis, the specific surface area is more than or equal to 200m 2 /g, the fixed carbon content is more than or equal to 45%, the pH value is between 8.0 and 9.5, and the mass ratio R of alkaline oxide to acidic oxide in ash is between 0.25 and 0.65.

Description

Coupling method for oil-containing sludge oil gas recovery and biochar preparation Technical Field The invention relates to the technical field of oil-containing sludge recycling, in particular to a coupling method for oil-containing sludge oil gas recovery and biochar preparation. Background With the rapid development of the petroleum industry, various types of oily sludge generated during petroleum and natural gas exploration, development, refining, storage and transportation are increasing. The waste sources are various (including floor sludge, large tank sludge, oil-containing scum and the like), the components are complex (such as petroleum hydrocarbon, heavy metal, clay, rock debris and the like), the waste sources are listed in the national hazardous waste directory, the HW08 hazardous waste is the important challenge for the industry in high-efficiency recycling and harmless treatment. At present, pyrolysis technology is one of the mainstream methods for treating oily sludge and recovering oil and gas resources. However, the prior art is mainly designed by taking single recycled pyrolysis oil gas resource as a guide, and because the pyrolysis raw material has large oil content change range, the residue after pyrolysis is unstable in nature and contains pollutants such as heavy metal, polycyclic aromatic hydrocarbon and the like, the pyrolysis residue is usually further treated by means of incineration, cement kiln co-firing, safe landfill and the like, so that the resource utilization rate is low, the secondary treatment cost is high, and in order to pursue the resource value of the residue, part of research attempts are made to prepare the residue into an adsorption material or a soil conditioner, but complicated subsequent activation or modification procedures are often required, the economy is poor, and industrialization is difficult. On the other hand, although the technology for preparing the high-added-value biochar by taking the pure biomass as the raw material is mature, the raw material cost is high, the process is independent, and the technology is difficult to couple with the existing oily sludge treatment facility. Therefore, the current process focusing on oil gas recovery cannot solve the problem of residue outlet, and the process focusing on biochar preparation needs to face high raw material or post-treatment cost. The development of a synergistic coupling technology capable of synchronously and efficiently recycling oil gas and converting residues into high-quality directly applicable biochar in situ, and realizing closed loop of pollutant disposal-resource recycling-product utilization, has become a technical bottleneck to be broken through in the field. Disclosure of Invention The invention aims to provide a coupling method for oil-containing sludge oil gas recovery and biochar preparation, which aims to solve the problems. The invention provides a coupling method for oil-containing sludge oil gas recovery and biochar preparation, which comprises the following steps: (1) Raw material construction, namely compounding oily sludge and biomass waste to form a composite raw material with a clay-carbon precursor structure; the oil content of the oil-containing sludge in the composite raw material obtained after the compounding is 15% -40%, the content of the natural clay mineral is 10% -30%, and the water content is 50% -60%; The biomass waste is an agricultural or forestry processing byproduct, and the addition amount of the biomass waste accounts for 5% -25% of the total mass of the composite raw material; (2) Performing coupling pyrolysis, namely placing the composite raw materials in inert atmosphere, and performing program temperature control coupling pyrolysis; Carrying out slow pyrolysis in a first temperature zone of 200-400 ℃ at a heating rate of 3-5 ℃ per minute, and preserving heat for 60-90 minutes at the tail end of the temperature zone; Heating to a second temperature region of 500-700 ℃, raising the heating rate to 10-20 ℃ per minute, and preserving heat for 60-120 minutes; (3) And outputting products, namely respectively collecting and condensing oil gas products generated in the first temperature zone and the second temperature zone, and collecting solid biochar obtained after the second temperature zone is finished. Preferably, in the step (1), the oil-containing sludge is a mixture of crude oil and crude oil product storage tank bottom sediment, ground oil sludge and dehydrated oil-containing scum, wherein the oil content of the crude oil and crude oil product storage tank bottom sediment is 30% -60%, the water content is 20% -40%, the solid content is 3% -6%, the oil content of the ground oil sludge is 5% -15%, the natural clay mineral content is 30% -70%, the water content is 30% -50%, the oil content of the dehydrated oil-containing scum is 8% -10%, the water content is 75% -80% and the solid content is 6% -8%. Preferably, in step (1), the natural clay mineral is m