“The wind blows through sparse elm and willow trees, and heavy frost ripens the pears and jujubes”. In this season of harvest, Feng'an Coking Project has made another significant achievement. On October 1, 2022, the crude benzene distillation unit of the gas purification system at Feng'an Coking project successfully produced crude benzene, marking the full-scale start-up of all process units in the gas purification system designed by Huatai Yongchuang.

Feng'an Coking Project is the first coking project undertaken by our company. From design and construction to commissioning and start-up, every Huatai employee has made tireless efforts. Every member of our chemical engineering team devoted themselves wholeheartedly to the design and review of the gas purification plant. Overcoming numerous challenges such as limited manpower and a tight schedule, and under the leadership of the company’s management, they upheld a spirit of perseverance and successfully completed the design of the entire gas purification plant.

The integrated gas purification unit of Feng'an Coking Project primarily consists of a gas condensation and exhauster unit, a H2S and HCN removal unit, an ammonia recovery unit, a benzene recovery unit, a storage and transportation unit, and external pipelines.

Gas condensation and exhauster unit and H2S and HCN removal unit

In accordance with the unique production requirements of the Feng'an Project, the gas condensation and exhauster unit is designed to comprise two gas systems - Phase I gas system and Phase II (covering the old plant) gas system. Each gas system can operate independently to enable system switching during production operations. The H2S and HCN removal unit adopts a “single-tower” wet oxidation desulfurization process which features a simple process flow, a small footprint, energy efficiency and ease of operation, compared to traditional desulfurization processes.

Ammonia Recovery Unit and Benzene Recovery Unit

The crude benzene distillation unit employs a vacuum benzene stripping process, in which the boiling point of the rich oil is lowered and the volatility of benzene compounds is increased, allowing benzene compounds to be stripped from the rich oil below the operating temperatures under atmospheric pressure. This process offers advantages such as low energy consumption, minimal wastewater generation, and reduced waste gas emissions.

Tailored VOCs treatment processes are adopted to suit varying characteristics of exhaust gases from different units of the COG purification plant. Desulfurization regeneration exhaust gas with higher oxygen content is fed into the coke oven combustion system, while VOCs vent gas with lower oxygen content is routed, via a pressure balancing system, to the negative-pressure gas system upstream of the gas exhauster. This enables efficient resource utilization of coking waste gas while effectively improving the production and operating environment of the gas purification unit.

Feng'an Integrated Coking Gas Purification Unit is the first full-process gas purification project designed and commissioned by our company, representing a breakthrough and a significant milestone of our company to expand into the chemical by-product recovery sector.