Technology

Introduction

1. Background

   SINOPEC has developed and commercialized Residue Hydrotreating Technology (RHT) with the catalyst grading technology. RHT process is a fixed bed hydrotreating technology to process inferior residue. In this technology residue is hydrotreated on RHT series catalysts to remove sulfur, metal, nitrogen, carbon residue and asphaltene. The main product, hydrotreated residue, is a qualified RFCC feed for further cracking to produce more light oil and low-carbon olefins. RHT has high yield of liquid product and environment friendly, which can significantly improve the efficiency of refinery.

   RHT-RFCC is an ideal technology for residue conversion. Although the investment and operation cost of the residue hydrogenation unit is relatively high, due to the improvement of the feed property of the RFCC unit, the product quality and light oil yield of the RFCC unit are improved and the RFCC catalyst cost is reduced. Therefore, the RHT-RFCC combined technology has good economic benefits. RHT improves the properties of residue hydrogenation products, reduces metal, sulfur, nitrogen, carbon residue content in RFCC feed, and improves the proportion of polycyclic aromatic hydrocarbons. The high value liquid product yield of RFCC products is effectively enhanced, thus the economic benefit of RHT - RFCC combination technology is greatly improved.

   Key indicators of RHT product: The mass yield of product >90%; HDS rate >90%; HDM rate >90%; HDN rate >40%; HDCCR rate >50%.

2. Technology Process

   The residue mixed with hydrogen passes through the guard reactor and the main reactor to remove metals, sulfur, nitrogen and residue carbon. After hydrotreating reaction, the reaction product goes to the separation and fractionation. Hydrogen is recycled, and the hydrogenated heavy oil goes to the catalytic cracking unit as feedstock (PFD image attached).
    
3. Main process conditions
   
   ▪️ Pressure: 13.0MPa~17.0MPa
   ▪️ LHSV: 0.2h^-1~0.4h^-1
   ▪️ Reaction temperature: 350°C~415°C
   ▪️ Hydrogen oil ratio: 500-1000Nm³/m³

Technical Features

Advantages of RHT:

1. Strong adaptability of raw materials to provide High Quality Feed for RFCC.
2. ailored catalyst grading technology. Good stability and high activity of grading catalysts.
3. High metal deposition capacity to ensure longer cycle length.
4. Reasonable utilization of hydrogen to reduce energy consumption and processing cost.
5. High efficient reactor inlet distributor.

Catalysts for RHT

RHT is supported by the third and fourth generation RHT series catalysts.

Application Performance

There are 12 sets of residue hydrotreating industrial units constructed by RHT technology, with a total processing capacity of 38.2 million tons per year, and the largest one has a processing capacity of 7.8 million tons per year. Eight of them have been completed and put into operation, and four are under construction.

The RHT series catalysts have been used in 25 sets of residue hydrotreating units worldwide for more than 100 times, and all have achieved good industrial application performance. The industrial application results show that RHT series catalysts have the characteristics of high impurity removal activity, high metal holding capacity, good carbon residue reduction effect, good hydrogenation selectivity and long service life.

References

Sinopec Research Institute of Petroleum Technologies, 7th Sep 2022, Residue Hydrotreating Technology (RHT)