The special operation certificate of hydrogenation process is a kind of work permit, and only those who have obtained the special operation certificate of hydrogenation process can work at their posts. The validity period of the special operation certificate is 6 years, and it will be reviewed once every 3 years. After 6 years, it needs to be re-examined and updated. The operation certificate for special operations is commonly known as the employment certificate. You can't do this job until you get a job license.