The company has hired an engineering consultant to carry out design work on the upgrade which is expected to be complete by 2015-16.
In addition, a new pipeline from Nairobi to the western town of Eldoret is expected to be completed by August.
Once operational, the facility is expected to deliver fuel at 600,000 liters per hour, compared with the current 200,000 liters per hour.
Standard Chartered has been commissioned to assist the refinery on the $784m upgrade, the bank is expected to raise 75% of the funds while the rest would be provided by shareholders.
The state holds 50% stake in the refinery and the balance is held by Essar Energy Overseas, while the pipeline company is wholly owned by the Kenyan government, according to Bloomberg.
