Introduction to the design scheme of crude benzol hydrogenation unit:

Crude benzol hydrogenation technology

In China, crude benzene is deeply processed, and the manufacturers producing pure benzene are mainly divided into two categories: one is to produce pure benzene by pickling, the other is to produce pure benzene by crude benzene hydrogenation process. The benzene produced by the acid pickling process has low purity, and it can not effectively separate toluene and xylene, and it can not achieve the emission standard of environmental protection. In addition, the product quality is low, and the production cost is high, which has been banned by the state and banned within a time limit. Now the crude benzene hydrogenation process has become the main process of crude benzene refining.

This technology adopts the domestic self-developed crude benzol low-temperature hydrotreating technology. The main process is that the crude benzol enters the hydrogenation process after removing the heavy benzene through raw material pretreatment, and all impurities in the crude benzol, mainly thiophene, are removed by low-temperature hydrogenation. Sulfide is converted into H2S, nitride into NH3, oxides into H2O, and unsaturated hydrocarbons are hydrogenated to saturation; Then the impurities are removed by conventional distillation and extractive distillation. Products include pure benzene, toluene, xylene, non aromatic and heavy benzene, among which, the main products are pure benzene, toluene and xylene.

On the basis of absorbing years of practical production and operation experience of existing similar units in China, our company has made targeted program optimization for crude benzene hydrogenation process:

① Optimization of Crude Benzol Hydrogenation Process

..: Raw material pretreatment is added. A heavy component removal tower is set to remove heavier components at a lower temperature under reduced pressure, and then fractionate before hydrogenation. The hydrogenation load was partially reduced. The adaptability of the unit to various domestic raw materials is improved.

Second: Prevent coking. The heavy fraction tower is operated under vacuum condition, and the tower bottom temperature is low. A special reboiler is used to reduce the gasification rate and effectively inhibit coking.

Third: process optimization. According to the actual operation experience of existing crude benzol hydrogenation units in China, many local adjustments and optimizations have been made to the original process flow.

② Optimization of Extractive Distillation Process

The sulfolane extraction distillation process developed by RIPP is used to separate aromatic hydrocarbons. This technology is used to produce benzene, toluene and xylene. It has the advantages of excellent product quality, low investment, low energy consumption and non corrosion of equipment.

Hydrogenation condition: T=300-380 ℃ P=3.0-4.0MPa

Light benzene and heavy aromatics (C9+) are separated from crude benzene through the pre fractionation tower. The heavy aromatics are used to produce coumarone, and the light benzene is used for hydrogenation. The light benzene gets the hydrogenation oil through the pre reactor, evaporator and reactor, and the recycle gas is separated through the high-pressure separator for recycling. The hydrogenation oil enters the liquid-liquid extraction and distillation system after the tail gas is removed from the stabilizer. Aromatic fraction and non aromatic fraction are obtained. Pure benzene, pure toluene and mixed xylene are separated from aromatic fraction by distillation system. The circulating gas is continuously discharged from the system, and the hydrogen produced by PSA method is continuously added.

Technical features:

The production technology is mature and the operation is safe and reliable.

The operation control is reliable and practical, with a high degree of automation.

Low operation cost and short payback period.

Some application achievements

* Construction unit scale

1. Hebei Yida Chemical Co., Ltd. 25000 tons/year

2 Heilongjiang Xingsheng Juda Chemical Co., Ltd. 50000 tons/year

3 Hebei Yifeng New Energy Co., Ltd. 50000 tons/year

4 Jiangsu Shengyun Chemical Co., Ltd. 50000 tons/year

5. Heilongjiang Jintai Chemical Co., Ltd. 50000 tons/year

6 Shandong Huineng Chemical Technology Co., Ltd. 100000 tons/year

7 Anhui Zhuotai Chemical Co., Ltd. 200000 tons/year