The purchase of a small refinery with only a 7,000 - barrel - per-day capacity in 1967 led to the establishment of Esso Sriracha Refinery. Two years later, in response to the high demand for petroleum products generated by Thailand's fast - growing economy, Esso decided to build new refining unit to raise its capacity to 35,000 bpd. The capacity expansion was completed in 1971. Due to increasing demand, the refinery crept its capacity to 46,000 bpd. By 1976.

In 1985 , its capacity was raised to 63,000 bpd. Later , the government approved Esso's two-phase plan in 1991 to boost the nameplate capacity to 145,000 bpd.

At present, the refinery can refine 170,000 barrels of crude oil per day to serve the Thai oil market.

In 1998, Esso began construction of the Thailand Aromatics Recover Project ( TARP) worth 16,000 million baht at the Sriracha refinery site. Construction of the aromatics plant completed in 1999. Following completion, the plant's operation has been integrated into the refinery. This state-of-the-art aromatics plant will annually produce 350,000 tons of paraxylene.

The Thailand Aromatics Recovery Project succeeded in many aspects - starting from cost management, quality of the work and safety performance. The project is a successful story of the cooperation between ExxonMobil's petroleum and chemicals businesses.

Continuous Catalytic Regenaration and Reformers (CCR ) convert low-octane fuels into high-octane fuels for production of various grades of unleaded gasoline. The unit consists of a 9,000 bpd. Powerformer and a 20,000 bpd continuous catalytic reformer.

Vacuum Pipestills (VPS) produce asphalt from heavier oils from the atmospheric pipestills. The Sriracha refinery has two vacuum pipestills - the first pipestill has a capacity of 8,000 bpd., and the second one has a capacity of 41,000 bpd. The lighter oils are send to the fluidized catalytic cracking units.

A Fluidized Catalytic Cracking Unit (FCCU) converts fuel oil into lighter diesel and gasoline to serve the increasing demand of transportation oils. The unit has a capacity of 33,000 bpd.

Sulfur Recovery Units (SRU) produce liquid sulfur from hydrogen sulfide gas which is generated from Hydro- desulfurization units especially from low-sulfur diesel production. The are two 82-ton sulfur recovery units.

Tail Gas Clean Up Unit (TGCU) reduces sulfur dioxide in flue gases to ensure that emission of sulfur dioxide adheres to Government of Thailand emission requirements.

Desalination Plants supply the refining units with fresh water produced from seawater . The refinery's three desalination plants produce more than 3,000 tons of fresh water per day. Having foreseen that Chonburi province may face a fresh water supply problem, Esso Sriracha Refinery is the first refinery in Thailand that produces its own fresh water from seawater. The first desalination plant was installed in 1967.

Power Generators consist of four boilers and two gas turbine generators . The refinery's five  boilers produce a total of 120 tons of steam per hour. They have been designed and equipped with high standard protection tools.

The two gas turbine generators produce electricity  for the Esso Sriracha refinery with a total capacity of 50 megawatts. The gas turbine generators use natural gas and desulfurized gas from the refining process, which is an effective way to save energy and reduce the emission of sulfur dioxide into the air.