ORC Waste Heat to Power System
■ Project Overview
In the original process of Maoming Petrochemical's 4# diesel hydrotreating unit, 330 tons of refined diesel above 140°C was cooled by air coolers, consuming energy and releasing waste heat into the atmosphere.
This project retrofitted the original process flow. The refined diesel enters the ORC waste heat power generation unit directly. Utilizing the waste heat from the diesel, the unit has a designed power generation capacity of 1750kW, while simultaneously saving 450kW of electricity consumption from the air coolers.
■ Project Results
The project saves 4,870 tons of standard coal annually, reduces CO₂ emissions by 11,758 tons per year, and generates a net annual power output of 14.944 million kW·h. It saves 3.78 million kW·h in annual electricity consumption compared to the original air cooling process. The investment for this project is recovered within three years, demonstrating excellent energy-saving effects and economic viability.
The project received the German Energy Agency (dena) Energy Efficiency Nomination Award.
Direct expansion generator set series
■ Project Overview
The styrene unit of the Plastic Plant at Sinopec Qilu Branch adopted a 1MW extraction-backpressure turbine direct-expansion generator set. It reduces the pressure of 1.5MPaG superheated steam to 0.33MPaG for use by various consumers. This meets process requirements while simultaneously converting this portion of pressure energy into electrical energy.
■ Project Achievements
The project achieves an annual energy saving of 2,400 tons of standard coal, an annual emission reduction of 5,982 tons of CO₂, and an annual net power generation of 6 million kW·h. The investment in this project is recovered within two years, demonstrating excellent energy-saving effects and economic viability.
Steam enhanced heat pump series
■ Project Overview
The Huizhou Petrochemical "Three Sludges" Treatment and Waste Heat Utilization Unit mainly generates and utilizes waste heat steam through incineration. The steam pressure produced by the waste heat boiler is approximately 1.0MPa. However, due to the introduction of external steam into the original low-pressure steam (network), the network pressure rose to 1.5MPa, preventing the waste heat steam from being merged into the network. To solve this problem, a waste heat steam upgrading and reuse system is required to improve the quality of the waste heat steam before merging it into the network. This achieves resource recovery, reduces noise pollution, and increases user benefits.
Huahang Shengshi has completed the validation of the first set of processes in the petrochemical industry, including Maoming Petrochemical, Shijiazhuang Refining and Chemical, Baling Petrochemical, Jiujiang Petrochemical, Qingdao Refining and Chemical, Qilu Petrochemical, and Huizhou Refining and Chemical. In the future, ORC waste heat recovery process package, steam temperature and pressure reduction direct expansion power generation, low-grade steam upgrading and reuse can be adopted in all new, renovated, and expanded projects to achieve comprehensive utilization of waste heat and pressure.