Oil and Natural Gas Production Facilities
Oil and natural gas production facilities emit hazardous air pollutants and other VOCs, which may contribute to the health problems of the employees as well as the community. The chemicals emitted include benzene, toluene, ethyl benzene, xylenes, n-hexane, and VOCs. Benzene exposure in the short term may cause severe irritation of the skin, eyes, and upper respiratory tract. Over long periods of time, it may cause blood disorders, reproductive and developmental disorders, and cancer. Toluene long-term exposure may cause nervous system effects, irritation of the skin, eyes and respiratory tract, headaches, and birth defects. Ethylbenzene may cause short-term effects of throat and eye irritation, chest construction, and dizziness. It may cause long-term effects of blood disorders. Xylenes may cause short-term effects of nausea, vomiting, and neurological effects. Long-term effects may impair the nervous system. n-Hexane may cause short-term effects of dizziness, nausea, and headache. It may cause long-term effects of numbness in the extremities, muscular weakness, blurred vision, headaches, and fatigue. VOCs can help form ground-level ozone as part of smog, and cause breathing difficulties and severe respiratory problems in susceptible populations such as the young, the elderly, and those with asthma.
Best Practices for the Natural Gas and Crude Oil Extraction Industry (See endnote 65)
- • Optimize the glycol dehydration system by modifying the process using diethylene glycol or ethylene glycol instead of triethylene glycol. Replace glycol dehydrators with desiccant dehydrators.
- • Install VOC controls on all storage tanks used to temporarily hold liquids from the production and transmission of oil and natural gas, starting with those which are most prone to produce emissions of the VOCs and air toxics including benzene.
- • Evaluate and eliminate all emissions to the air from valves, pumps, seals, pressure relief valves, and other equipment.
- • Remove hydrogen sulfide, carbon dioxide, helium, nitrogen, and other substances from raw natural gas to produce pipeline quality dry natural gas.
- • Use special equipment to separate and treat the gas and liquid hydrocarbons from the flowback and then prepare the products for sale instead of disposal.
- • Use pit flaring, which is a horizontal flare burner that discharges into a pit, to burn VOCs and methane if they cannot be collected efficiently and it is not a safety hazard.
- • Improve the compressors of natural gas by equipping them with dry seals.
- • Use pneumatic controllers that are not gas driven.
- • Strengthen the leak detection and repair requirements for natural gas processing plants.
- • Improve the air toxics standards by doing a new assessment 8 years after the standard is issued and also a technology review every 8 years after the standard is issued.
- • Replace the gas starters with air or nitrogen in compressors/engines.
- • Conduct frequent inspection and maintenance at remote sites.
- • Test and repair the pressure safety valves.
- • Frequently inspect and maintain properly gate stations, surface facilities, compressor stations, processing plants, and booster stations.
- • Inspect, service, and repair pipelines, pressure safety valves, and pipeline connections on a regular basis.
- • Convert water tank blankets from natural gas to produced carbon dioxide gas and eliminate unnecessary equipment and/or systems.
- • Install vapor recovery units on storage tanks and recover gases during condensate loading.
- • Connect the casing of wells to the vapor recovery units.
- • Install properly operating flares to destroy excess gases and toxic air pollutants.
- 16. Natural Sources
These sources vary by intensity and quantity of type of pollutants based on a variety of factors. They are:
- • Bodies of water that produce methane through the digestive process of marine life and reaction within sediments
- • Digestive gasses, such as methane, which are produced by the digestion of food in cattle and other animals
- • Dust which comes from areas of little or no vegetation
- • Forest fires caused by lightning or spontaneous combustion producing smoke, ash, dust, nitrogen oxides, carbon dioxide, and other air pollutants
- • Geysers produce hydrogen sulfide, arsenic, other heavy metals, etc.
- • Lightning converts atmospheric nitrogen into nitrogen oxides.
- • Plants and trees, especially pine trees, which release VOCs
- • Radioactive material which releases radon gas into the atmosphere from the Earth’s crust
- • Sea salt releasing sodium chloride and other particles into the air from the action of wind over the body of salt water
- • Soil where microbial action in soils forms and releases nitrogen oxides
- • Termites, which are the second-largest source of methane production because of their normal digestive process
- • Volcanoes which produce smoke, ash, carbon dioxide, sulfur dioxide, and other air pollutants
- • Wetlands in which microbial action produces and releases to the atmosphere a significant amount of methane.
Best Practices for Natural Sources
Basically there are no Best Practices for natural sources which would be practical other than carrying out clean-up activities where appropriate.
17. Petroleum Refining
Crude oil is processed to produce automobile gasoline, diesel fuel, lubricants, and other petroleum-based products. The toxic air pollutants including benzene come from storage tanks, equipment leaks, process vents, wastewater collection, and treatment systems at the facility. The emission of air toxics occurs during production, transporting, storage, separation, upgrading, leaks from pumps, compressors, valves, flanges, and other equipment used in oil and natural gas production, transmission, and storage. The air toxics include benzene and other VOCs as well as methane, an important greenhouse gas.
Best Practices for Petroleum Refineries
- • Develop appropriate timely inspection procedures for determining if equipment is leaking and make appropriate corrections.
- • Keep appropriate records of the equipment leaking times and sites.
- • Use preventive maintenance where appropriate to keep equipment from leaking.
- • Determine if industrial flares are operating appropriately on a timely basis and take corrective action when necessary.
- 18. Power Plants (See External Combustion Sources-Electric Power Plants above)
- 19. Publicly Owned Treatment Works (Public Sewage) (See Chapter 11, “Sewage Disposal Systems”)
These plants treat wastewater from residential, commercial, and industrial sources. Depending on the types of commercial and industrial plants utilizing the publicly owned treatment works for disposal of their liquid waste and possibly from combined sewers on their properties, there will be considerable variation in the potential air toxics which will be emitted. Typically, there is a release of VOCs from the wastewater including xylenes, methylene chloride, toluene, ethylbenzene, chloroform, tetrachloroethylene, and naphthalene.
Best Practices for Publicly Owned Treatment Works (Public Sewage) (See Chapter 11, “Sewage Disposal Systems”)
20. Pulp and Paper Mills
Wood and non-wood sources of fiber are turned into pulp by use of chemicals, mechanical grinding, or a combination of both. Pulp may also be produced from the re-pulping of recovered paper. The fibrous masses are washed, screened, and sometimes bleached. The individual fibers are then mixed with water and the slurry is sprayed onto a flat wire screen where the water is squeezed out and the fibers bond together to form paper of different qualities and thicknesses. The air emissions from the pulp and paper production contain process gases, which vary with the raw materials, and may include total reduced sulfur compounds, causing obnoxious odors, which are typically found in kraft and sulfite mills. The kraft chemical process, which uses sodium hydroxide and sodium sulfide to pulp the wood, is the most important process used in the world for virgin wood. In the kraft process, about half of the wood is dissolved and that solution plus the used sodium hydroxide and sodium sulfide becomes a substance called black liquor. The black liquor is then washed from the pulp and sent to a kraft recovery system where the two chemicals are separated for reuse while the dissolved organic material is prepared to be a fuel to make steam to generate electricity and heat to be used in the pulping process. The process consists of pulping chemicals, recovery boilers for dealing especially with particulate matter and sulfur dioxide, and lime kilns for reducing sulfur compounds.
Process gases also include particulate matter, nitrogen oxides, VOCs, fluorine, carbon dioxide, and methane. Other emissions may come from the materials used in the heating process and the energy producing process. Toxic air pollutants are produced including chloroform, fluorine, formaldehyde, methanol, acetaldehyde, methyl ethyl ketone, and metals. Other air pollutants include particulate matter and chlorine. (See endnote 5.)
The pulp and paper industry uses a very substantial amount of energy. This is over 15% of the manufacturing energy used in the United States. The use of energy sources significantly adds to the amount of criteria pollutants, greenhouse gases, and hazardous air pollutants. (See endnote 73.)
Best Practices Pulp and Paper Mills (See endnote 72)
- • Collect and incinerate emissions to completely oxidize all reduced sulfur compounds coming from the process of working with black liquor, brown pulp, unbleached pulp, and condensate.
- • Use a standby incineration system to destroy high concentrations of gases from condensates and digester events.
- • Use a standby incinerator to incinerate low concentrations of gases when the industrial plant is close to a residential area.
- • Use an oxygen-activated sludge process to capture odors from wastewater treatment plants.
- • Ensure black liquor is oxidized prior to evaporation.
- • Concentrate black liquor in the evaporator to reduce sulfur emissions.
- • Control the combustion temperatures to properly incinerate sulfur emissions.
- • Control excess air to reduce nitrogen oxide emissions.
- • Collect sulfur dioxide emissions by absorption in an alkaline solution.
- • Use low sulfur content fuel and control excess oxygen to reduce sulfur dioxide emissions.
- • Use electrostatic precipitators in recovery boilers, auxiliary boilers, and lime kilns.
- • Use an alkaline process with scrubbers to remove the acid gases.
- • Incinerate VOC emissions from mechanical pulping of wood.
- 21. Solid Waste Landfills (See Chapter 12, “Solid Waste, Hazardous Materials, and Hazardous Waste Management”)
Solid waste landfills produce landfill gas in the presence of microorganisms and the chemical reactions in the waste. This gas including methane, carbon dioxide, ammonia, and sulfides which enter the ambient air.
Best Practices for Solid Waste Landfills (See Chapter 12, “Solid Waste, Hazardous Materials, and Hazardous Waste Management”)
22. Solid Waste Incinerators (See Chapter 12, “Solid Waste, Hazardous Materials, and Hazardous Waste Management”)
Solid waste incinerators include waste incineration plants and waste-to-energy plants. Municipal, commercial, institutional, and industrial incineration is a means of reducing the quantity of solid waste to a point where the disposal of the remnants takes up a small amount of land. A number of pollutants may be released during this process, including cadmium, lead, mercury, dioxin, sulfur dioxide, hydrogen chloride, nitrogen dioxide, and particulate matter. These pollutants are a mixture of criteria pollutants and toxic air pollutants. Hospital/medical/infectious waste incineration is the destruction of solid waste materials used in all facets of diagnosis, treatment, or immunization of humans or animals in such a manner that the remnants can no longer potentially cause disease. This is accomplished in special incinerators.
Best Practices for Solid Waste Incinerators (See Chapter 12, “Solid Waste, Hazardous Materials, and Hazardous Waste Management”)
23. Spills and Run off from Stored Chemicals and Storage Tanks
Ground or surface water is readily contaminated when petroleum products and chemicals are mishandled and spills occur, resulting in the chemicals seeping into the ground and to the water supply or becoming part of runoff and going into surface bodies of water. A single spill or leakage can spread out into the ground and become a source of contamination for many years. In numerous areas, there are a substantial number of underground storage tanks which have been used over many years for holding a variety of products including substances which are very hazardous. These tanks may be found in gas stations (the most common place), airports, dry cleaners, homes, agricultural areas, etc. An immediate problem occurs when there are leaks and spills because of poor housekeeping, overfilling of the tanks, sloppiness in loading and unloading the product, and poor maintenance and inspection of the facility. A longterm problem occurs when the tanks become corroded and start to leak product into the ground. A recent example of an overflow from the tanks into a drinking water supply occurred on January 9, 2014, when toxic chemicals were released from a storage tank spill into the Elk River which is the drinking water supply for Charleston, West Virginia.
This affected 300,000 people. The spill resulted in individuals going to the emergency room because of nausea, eye irritation, and vomiting. The chemicals released were also potentially carcinogenic.
Best Practices for Spills and Run off from Stored Chemicals and Storage Tanks
The Best Practices to prevent spills and leakage from aboveground storage tanks and
underground storage tanks include:
- • Inspect all pumps, hoses, and connections between pipes for leaks monthly.
- • Check for loose fittings, worn gaskets, or damaged rubber nozzles monthly.
- • Check underground storage tank equipment and dispensers for leaks and structural problems monthly.
- • Make frequent inspections of all tanks and equipment during very cold weather and very hot weather.
- • Inspect aboveground storage tanks weekly for leaks and monthly for deterioration.
- • Check secondary containment areas for any sheen, which would indicate spillage.
- • Keep an inspection log with the results of the inspections, dated and signed.
- 24. Toxic Waste Storage, Transfer, Treatment, and Disposal Facilities
These include facilities for industrial wastewater treatment, industrial waste, solvent recycling, and used oil recovery. Toxic air pollutants including chloroform, toluene, formaldehyde, and xylene are released from the tanks, from process events, through equipment leaks, from the containers, from surface impoundments, and through the piping system of the transfer, treatment, and disposal of the wastes.
Best Practices for Toxic Waste Transfer, Treatment, and Disposal Facilities (See Chapter 12, “Solid Waste, Hazardous Materials, and Hazardous Waste Management”)