Method and apparatus for hydrotreating waste plastics

Abstract

The invention relates to a method for hydrotreating waste plastics. The method comprises the following steps: S1, adding waste plastics into a first liquid phase hydrogenation reactor, and carrying out a hydrocracking reaction under the conditions that the pressure is 1-3 MPa, the temperature is 500-700 DEG C and the time is 20-90 minutes to obtain a cracking product; S2, feeding the cracking product or the cracking product and an oil raw material into a second liquid phase hydrogenation reactor, and carrying out a hydroisomerization reaction to obtain an isomerization product, wherein the weight ratio of the cracking product to Fischer-Tropsch wax is 1:(0.5-3), the conditions of the hydroisomerization reaction are as follows: the pressure is 10-15 MPa, the temperature is 300-500 DEG C, and the reaction time is 1 hour, and the oil raw material is at least one selected from paraffin-based distillate oil and Fischer-Tropsch wax; and S3, performing distillation or high-pressure separationon the isomerization product to obtain lubricating oil base oil, diesel oil and hydrocarbon gas. The invention also relates to a device for hydrotreating waste plastics.

Description

technical field [0001] The invention relates to a method and device for hydrogenation treatment of waste plastics, in particular to a method for treating waste plastics with a liquid phase hydrogenation treatment device. The invention uses a liquid-phase hydrogenation reactor to carry out hydrocracking and hydrogenation isomerization. The liquid-phase hydrogenation reactor adopts a multi-point quantitative hydrogen replenishment method, cancels a circulating hydrogen compressor, and improves hydrogenation efficiency. Background technique [0002] According to the latest information from China Petroleum and Chemical Network: China's annual waste plastic production is about 34.13 million tons, and the recycling amount reaches more than 24.878 million tons, accounting for about 30% of China's plastic consumption. Waste plastic resources are called "the second mineral deposit of human beings" by modern economists. Plastic raw materials are chemical products extracted from natur...

AI Technical Summary

Problems solved by technology

This one-step processing method causes the two raw materials to be heated quickly before they are fully mixed; at the same time, due to the high heating rate, the raw materials that have just been mixed will directly generate coke products before they have time to react. The liquid product yield is on the low side, only about 80wt%

[0006] Chinese patent CN1434100A uses waste plastics and oil mixed raw materials to produce fuel oil through pyrolysis. This method solves the problem of utilization of waste plastics, heavy oil and waste oil, but there is a high cracking initiation temperature, and light oil products such as Low yields of gasoline and diesel fractions, and the heavy oil mentioned is a long-chain, large-molecular-weight, high-viscosity oil produced during petroleum production

At the same time, in order to increase the mass transfer, the ratio of hydrogen to oil is usually much higher than that required for the reaction, and the low flow rate of the liquid will result in insufficient wetting of the catalyst.

Images