The oil industry is categorized into oil drilling, petroleum refining, petrochemistry.
Oil Well Drilling - Oil-well drilling occurs at depths of several hundred meters to several thousand meters below ground level, where the oil reservoirs are located. A flowing artesian state is achieved by drilling and then manipulating pressures. Valves are used in controlling the flow of oil at the wellhead.
Oil Well Refining - A variety of petroleum products are produced by distilling crude oil. Manufacturing processes include atmospheric distillation, distillation under reduced pressure, catalytic cracking, catalytic reforming, alkylation, desulfurization, and preparation. Processes occur between classes 125 to 4500, and valves utilize various materials, including: cast Iron, carbon steel, low-alloy steel, high-alloy steel, and low-temperature steel.
Petrochemicals - Ethylene plants carry out a key process that produces intermediate materials for the petrochemical industry. Valves used in ethylene plants are similar to those in oil refineries, but they are required to follow much stricter standards for high temperature, extreme cold, high pressure, and corrosion-resistance. Many require specialized materials and specifications.
Characteristics of petroleum refining and petrochemical valves - Crude oil, heavy oil, volatile oil, acids and alkaline are hazardous fluids. Within the processes, valves and fittings may encounter extremes of cold and hot as well as flammable and explosive fluids and gases. Petroleum refining is a complex process and demands strict anti-corrosion standards. Because refineries are designed for long periods of operation, anti-corrosion is an essential specification for the valves and fittings. Due to the risks posed by disasters such as earthquakes and fires, valves for pipelines and tanks must be designed so as not to cause secondary disasters. In petroleum refining, there are common industry standards that specify the selection of materials to match the conditions under which valves and fittings will be used.