Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP Environmental, Health, and Safety Guidelines for Natural Gas Processing The Environmental, Health, and Safety (EHS) Guidelines are recommendations should be based on the professional opinion technical reference documents with general and industry- of qualified and experienced persons. specific examples of Good International Industry Practice When host country regulations differ from the levels and (GIIP) 1. When one or more members of the World Bank Group measures presented in the EHS Guidelines, projects are are involved in a project, these EHS Guidelines are applied as expected to achieve whichever is more stringent. If less required by their respective policies and standards. These stringent levels or measures than those provided in these EHS industry sector EHS guidelines are designed to be used together Guidelines are appropriate, in view of specific project with the General EHS Guidelines document, which provides circumstances, a full and detailed justification for any proposed guidance to users on common EHS issues potentially applicable alternatives is needed as part of the site- specific environmental to all industry sectors. For complex projects, use of multiple industry-sector guidelines may be necessary. A complete list of assessment. This justification should demonstrate that the choice for any alternate performance levels is protective of industry-sector guidelines can be found at: human health and the environment. www.ifc.org/ifcext/enviro.nsf/Content/EnvironmentalGuidelines The EHS Guidelines contain the performance levels and Applicability measures that are generally considered to be achievable in new The EHS Guidelines for Natural Gas Processing cover facilities by existing technology at reasonable costs. Application production in gas to liquids (GTL) facilities including production of the EHS Guidelines to existing facilities may involve the of methanol, as well as common intermediate production of establishment of site-specific targets, with an appropriate synthetic gas known as “Syn-gas”, a mixture of carbon timetable for achieving them. monoxide and hydrogen. Annex A contains a description of The applicability of the EHS Guidelines should be tailored to the industry sector activities. Information on EHS issues related to hazards and risks established for each project on the basis of storage tank farms is provided in the EHS Guidelines for Crude the results of an environmental assessment in which site- Oil and Petroleum Product Terminals. specific variables, such as host country context, assimilative This document is organized according to the following sections: capacity of the environment, and other project factors, are taken into account. The applicability of specific technical Section 1.0 — Industry-Specific Impacts and Management Section 2.0 — Performance Indicators and Monitoring 1 Defined as the exercise of professional skill, diligence, prudence and foresight Section 3.0 — References and Additional Sources that would be reasonably expected from skilled and experienced professionals Annex A — General Description of Industry Activities engaged in the same type of undertaking under the same or similar circumstances globally. The circumstances that skilled and experienced professionals may find when evaluating the range of pollution prevention and control techniques available to a project may include, but are not limited to, varying levels of environmental degradation and environmental assimilative capacity as well as varying levels of financial and technical feasibility. APRIL 30, 2007 1 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP emissions include nitrogen gas contaminated with methanol 1.0 Industry-Specific Impacts vapor from methanol storage facilities; methane (CH4), carbon and Management monoxide (C O), and hydrogen from Syn-gas production units, The following section provides a summary of EHS issues and Fischer-Tropsch (F-T) or methanol synthesis units. associated with natural gas processing, which occur during the operational phase, along with recommendations for their Recommendations to prevent and control fugitive emissions management. Recommendations for the management of EHS include the following: issues common to most large industrial facilities during the construction and decommissioning phase(s) are provided in the • Regularly monitor fugitive emissions from pipes, valves, General EHS Guidelines. seals, tanks, and other infrastructure components with vapor detection equipment, and maintenance or 1.1 Environmental replacement of components as needed in a prioritized manner; Potential environmental aspects associated with natural gas • Maintain stable tank pressure and vapor space by: processing include the following: o Coordinating filling and withdrawal schedules, and • Air emissions implementing vapor balancing between tanks, (a • Wastewater process whereby vapor displaced during filling • Hazardous materials activities is transferred to the vapor space of the tank • Wastes being emptied or to other containment in preparation • Noise for vapor recovery); o Using white or other color paints with low heat absorption properties on exteriors of storage tanks for Air Emissions lighter distillate s such as gasoline, ethanol, and Fugitive Emissions methanol to reduce heat absorption. Potential for Fugitive emissions in natural gas processing facilities are visual impacts from reflection of light off tanks should associated with leaks in tubing; valves; connections; flanges; be considered; packings; open-ended lines; floating roof storage tank, pump, • Selecting and designing storage tanks in accordance with and compressor seals; gas conveyance systems, pressure relief internationally accepted standards to minimize storage and valves, tanks or open pits / containments, and loading and working losses considering, for example, storage capacity unloading operations of hydrocarbons. and the vapor pressure of materials being stored;2 The main sources and pollutants of concern include Volatile 2 Examples include: API Standard 620: Design and Construction of Large, Organic Compound (VOC) emissions from storage tanks during Welded, Low -pressure Storage Tanks (2002); API Standard 650: Welded Steel Tanks for Oil Storage (1998), and; European Union (EU) European Standard filling and due to tank breathing; floating roof seals in case of (EN) 12285-2:2005. Workshop fabricated steel tanks for the aboveground storage of flammable and non-flammable water polluting liquids (2005). For floating roof storage tanks; wastewater treatment units; Fischer- example, according to API Standard 650: Welded Steel Tanks for Oil Storage (1998), new, modified, or restructured tanks with a capacity greater or equal to Tropsch (F-T) synthesis units; methanol synthesis units; and 40,000 gallons and storing liquids with a vapor pressure greater or equal than 0.75 psi but less than 11.1 psi, or a capacity greater or equal to 20,000 gallons product up-grading units. Additional sources of fugitive and storing liquids with a vapor pressure greater or equal than 4 psi but less than 11.1 psi must be equipped with: fixed roof in conjunction with an internal APRIL 30, 2007 2 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP • Use supply and return systems, vapor recovery hoses, and total, rated heat input capacity of 50 Megawatt thermal (MWth) vapor-tight trucks / railcars / vessels during loading and is provided in the General EHS Guidelines. Guidance unloading of transport vehicles; applicable to processes larger than 50 MWth is provided in the • Use bottom-loading truck / rail car filling systems; and EHS Guidelines for Thermal Power. • Where vapor emissions contribute or result in ambient air Emissions related to the operation of power sources should be quality levels in excess of health based standards, install minimized through the adoption of a combined strategy which secondary emissions controls, such as vapor condensing includes a reduction in energy demand, use of cleaner fuels, and recovery units, catalytic oxidizers, vapor combustion and application of emissions controls where required. units, or gas adsorption media. Recommendations on energy efficiency are addressed in the Greenhouse Gases (GHGs) General EHS Guidelines. Significant amounts of carbon dioxide (CO2) may be emitted from Syn-gas manufacturing, mainly from CO2 washing, and Venting and Flaring from all combustion processes (e.g., electric power production Venting and flaring are an important operational and safety and byproduct incineration). Recommendations for energy measure used in natural gas processing facilities to ensure gas conservation and the management of greenhouse gas is safely disposed of in the event of an emergency, power or emissions are discussed in the General EHS Guidelines. At equipment failure, or other plant upset conditions. Unreacted integrated facilities, operators should explore an overall facility raw materials and by-product combustible gases are also approach in the selection of process and utility technologies. disposed of through venting and flaring. Excess gas should not be vented but instead sent to an efficient flare gas system for Exhaust Gases disposal. Exhaust gas emissions produced by the combustion of gas or other hydrocarbon fuels in turbines, boilers, compressors, Recommendations to minimize gas venting and flaring include pumps, and other engines for power and heat generation are a the following: significant source of air emissions from natural gas processing • Optimize plant controls to increase the reaction conversion facilities. Incineration of oxygenated byproducts at GTL rates; production facilities also generates CO2 and nitrogen oxides • Recycle unreacted raw materials and by-product (NOX) emissions. combustible gases in the process or utilize these gases for Guidance for the management of small combustion processes power generation or heat recovery, if possible; designed to deliver electrical or mechanical power, steam, heat, • Provide back-up systems to achieve as high a plant or any combination of these, regardless of the fuel type, with a reliability as practical; and • Locate the flaring system at a safe distance from floating roof with a liquid mounted mechanical shoe primary seal; or external residential areas or other potential receptors, and maintain floating roof with a liquid mounted mechanical shoe primary seal and continuous the system to achieve high efficiency. rim-mounted secondary seal, with both seals meeting certain minimum gap requirements and gasketed covers on the roof fittings; or closed vent system and 95% effective control device. See also American Petroleum Institute (API) Standard 2610: Design, Construction, Operation, and Maintenance of Terminal and Tank Facilities (2005). APRIL 30, 2007 3 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP Emergency venting may be acceptable under specific conditions be collected into a dedicated closed drain system and, after where flaring of the gas stream is not appropriate. For example, filtration, recycled back into the process provided the amine in GTL processing there could be streams containing high did not become contaminated as a consequence of being concentrations of carbon dioxide which, if sent to a flare system, spilled and/or collected; would extinguish the flare's flame; - venting of such streams to a • The water effluent from the stripping column of the Fischer- safe atmospheric location is an acceptable option. Standard risk Tropsch (F-T) Synthesis Unit, which contains dissolved assessment methodologies should be utilized to analyze such hydrocarbons and oxygenated compounds including situations. Justification for not using a gas flaring system should alcohols, organic acids and minor amounts of ketones, be fully documented before an emergency gas venting facility is should be re-circulated inside the F-T Synthesis Unit in considered. order to recover the hydrocarbons and oxygenated compounds; Wastewater • Acidic and caustic effluents from demineralized water Industrial Process Wastewater preparation, the generation of which depends on the quality Process wastewater and other wastewaters, which may be of the raw water supply to the process, should be contain dissolved hydrocarbons, oxygenated compounds, and neutralized prior to discharge into the facility’s wastewater other contaminants, should be treated at the onsite wastewater treatment system; treatment unit (WWTU). Recommended process wastewater • Blow-down from the steam generation systems and cooling management practices include: towers should be cooled prior to discharge. Cooling water containing biocides or other additives may also require • Prevention and control of accidental releases of liquids dose adjustments or treatment in the facility’s wastewater through inspections and maintenance of storage and treatment plant prior to discharge; and conveyance systems, including stuffing boxes on pumps • Hydrocarbon-contaminated water from scheduled cleaning and valves and other potential leakage points, as well as activities during facility turn-around (cleaning activities are the implementation of spill response plans; typically performed annually and may last for a few weeks), • Provision of sufficient process fluids let- down capacity to hydrocarbon-containing effluents from process leaks, and maximize recovery into the process and to avoid massive heavy-metals containing effluents from fixed and fluidized process liquids discharge into the oily water drain system; beds should be treated via the facility’s wastewater • Design and construction of wastewater and hazardous treatment plant. materials storage containment basins with impervious surfaces to prevent infiltration of contaminated water into Process Wastewater treatment soil and groundwater. Techniques for treating industrial process wastewater in this sector include source segregation and pretreatment of Specific provisions to be considered for the management of concentrated wastewater streams. Typical wastewater treatment individual wastewater streams include the following: steps include: grease traps, skimmers, dissolved air floatation, or oil / water separators for separation of oils and floatable • Amines spills resulting from the carbon dioxide alkaline solids; filtration for separation of filterable solids; flow and load removal system downstream of the Gasification Unit should APRIL 30, 2007 4 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP equalization; sedimentation for suspended solids reduction Stormwater: Stormwater may become contaminated as a result using clarifiers; biological treatment, typically aerobic treatment, of spills of process liquids. Natural gas processing facilities for reduction of soluble organic matter (BOD); chemical or should provide secondary containment where liquids are biological nutrient removal for reduction in nitrogen and handled, segregate contaminated and non-conta minated phosphorus; chlorination of effluent when disinfection is stormwater, implement spill control plans, and route stormwater required; and dewatering and disposal of residuals in from process areas into the wastewater treatment unit. designated hazardous waste landfills. Additional engineering Cooling water: Cooling water may necessitate high rates of controls may be required for (i) containment and treatment of water consumption, as well as the potential release of high volatile organics stripped from various unit operations in the temperature water, residues of biocides, and residues of other wastewater treatment system, (ii)advanced metals removal using membrane filtration or other physical/chemical treatment cooling system anti- fouling agents. Recommended cooling water management strategies include: technologies, (iii) removal of recalcitrant organics, cyanide, and non biodegradable COD using activated carbon or advanced • Adoption of water conservation opportunities for facility chemical oxidation, (iii) reduction in effluent toxicity using cooling systems as provided in the General EHS appropriate technology (such as reverse osmosis, ion Guidelines; exchange, activated carbon, etc.), and (iv) containment and • Use of heat recovery methods (also energy efficiency neutralization of nuisance odors. improvements) or other cooling methods to reduce the Management of industrial wastewater and examples of temperature of heated water prior to discharge to ensure treatment approaches are discussed in the General EHS the discharge water te mperature does not result in an Guidelines. Through use of these technologies and good increase greater than 3°C of ambient temperature at the practice techniques for wastewater management, facilities edge of a scientifically established mixing zone that takes should meet the Guideline Values for wastewater discharge as into account ambient water quality, receiving water use, indicated in the relevant table of Section 2 of this industry sector assimilative capacity , etc.; document. Recommendations to reduce water consumption, • Minimizing use of antifouling and corrosion-inhibiting especially where it may be a limited natural resource, are chemicals through proper selection of depth for placement provided in the General EHS Guidelines. of water intake and use of screens; selection of the least- hazardous alternative with regards to toxicity, Other Wastewater Streams & Water Consumption biodegradability, bioavailability, and bioaccumulation Guidance on the management of non-contaminated wastewater potential; and dosing according to local regulatory from utility operations, non-contaminated stormwater, and requirements and manufacturer recommendations; and sanitary sewage is provided in the General EHS Guidelines. • Testing for the presence of residual biocides and other Contaminated streams should be routed to the treatment system pollutants of concern to determine the need for dose for industrial process wastewater. Additional specific guidance is adjustments or treatment of cooling water prior to provided below. discharge. APRIL 30, 2007 5 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP Hydrostatic testing water: Hydrostatic testing of equipment and Wastes pipelines involves pressure testing with water (generally filtered Non-hazardous Waste raw water) to verify their integrity and to detect possible leaks. Non-hazardous industrial wastes consist mainly of exhausted Chemical additives (typically a corrosion inhibitor, an oxygen molecular sieves from the air separation unit as well as scavenger, and a dye) may be added. In managing hydro-test domestic wastes. Other non-hazardous wastes may include waters, the following pollution prevention and control measures office and packaging wastes, construction rubble, and scrap should be implemented: metal. General recommendations for the management of non- hazardous waste, including storage and disposal, are presented • Using the same water for multiple tests to conserve water in the General EHS Guidelines. and minimize discharges of potentially contaminated effluent; Hazardous Waste • Reducing the use of corrosion inhibiting or other chemicals Hazardous waste should be determined according to the by minimizing the time that test water remains in the characteristics and source of the waste materials and applicable equipment or pipeline; and regulatory classification. In GTL facilities, hazardous wastes • Selecting the least hazardous alternative with regards to may include bio-sludge; spent catalysts; spent oil, solvents, and toxicity, biodegradability, bioavailability, and filters (e.g., activated carbon filters and oily sludge from oil water bioaccumulation potential, and dosing according to local separators); used containers and oily rags; mineral spirits; used regulatory requirements and manufacturer sweetening; spent amines for CO2 removal; and laboratory recommendations. wastes. General recommendations for the management of hazardous waste are presented in the General EHS If discharge of hydro-test waters to the sea or to surface water is Guidelines. Industry-specific waste management practices are the only feasible alternative for disposal, a hydro-test water described below. disposal plan should be prepared considering location and rate of discharge, chemical use (if any), dispersion, environmental Spent catalysts: Spent catalysts from GTL production are risk, and required monitoring. Hydro-test water disposal into generated from scheduled replacements in natural gas shallow coastal waters should be avoided. desulphurization reactors, reforming reactors and furnaces, Fischer-Tropsch synthesis reactors, and reactors for mild Hazardous Materials hydrocracking. Spent catalysts may contain zinc, nickel, iron, Natural gas processing facilities use and manufacture significant cobalt, platinum, palladium, and copper, depending on the amounts of hazardous materials, including raw materials, particular process. Recommended waste management intermediate / final products and by-products. The handling, strategies for spent catalysts include the following: storage, and transportation of these materials should to be managed properly to avoid or minimize the environmental • Proper on-site management, including submerging impacts from these hazardous materials. Recommended pyrophoric spent catalysts in water during temporary practices for hazardous material management, including storage and transport until they can reach the final point of handling, storage, and transport, are presented in the General treatment to avoid uncontrolled exothermic reactions; EHS Guidelines. APRIL 30, 2007 6 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP • Return to the manufacturer for regeneration; and biological health and safety hazards described in the General • Off-site management by specialized companies that can EHS Guidelines (Occupational Health and Safety). recover the heavy or precious metals, through recovery The most significant occupational health and safety hazards and recycling processes whenever possible, or who can occur during the operational phase of a natural gas processing otherwise manage spent catalysts or their non-recoverable facility and primarily include the fo llowing: materials according to hazardous and non-hazardous waste management recommendations presented in the • Process Safety General EHS Guidelines. Catalysts that contain platinum or • Oxygen-Enriched Gas Releases palladium should be sent to a noble metal recovery facility. • Oxygen-Deficient Atmospheres Heavy ends: Heavy ends from the purification section of the • Chemical hazards Methanol Synthesis Unit are normally burnt in a steam boiler by means of a dedicated burner. Process Safety Process safety programs should be implemented due to Noise industry-specific characteristics, including complex chemistry The principal sources of noise in natural gas processing facilities reactions, use of hazardous materials (e.g., toxic, reactive, include large rotating machines (e.g. compressors, turbines, flammable, or explosive compounds), and multi-step reactions. pumps, electric motors, air coolers, and fired heaters). During Process safety management includes the following actions: emergency depressurization, high noise levels can be • Physical hazard testing of materials and reactions; generated due to release of high-pressure gases to flare and / • Hazard analysis studies to review the process chemistry or steam release into the atmosphere. General and engineering practices, including thermodynamics and recommendations for noise management are provided in the kinetics; General EHS Guidelines. • Examination of preventive maintenance and mechanical integrity of the process equipment and utilities; 1.2 Occupational Health and Safety • Worker training; and Facility -specific occupational health and safety hazards should • Development of operating instructions and emergency be identified based on job safety analysis or comprehensive response procedures. hazard or risk assessment using established methodologies such as a hazard identification study [HAZID], hazard and Oxygen-Enriched Gas Releases operability study [HAZOP], or a scenario-based risk assessment Leaks of oxygen-enriched from air separation units can create a [QRA]. fire risk. Oxygen-enriched atmospheres may potentially result in the saturation of materials, hair, and clothing with oxygen, which As a general approach, health and safety management planning may burn violently if ignited. Prevention and control measures to should include the adoption of a systematic and structured reduce on-site and off-site exposure to oxygen-enriched approach for prevention and control of physical, chemical, and atmospheres include: APRIL 30, 2007 7 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP • Installation of an automatic Emergency Shutdown System • Installation of an automatic Emergency Shutdown System that can detect and warn of the uncontrolled release of that can detect and warn of the uncontrolled release of oxygen (including the presence of oxygen-enriched nitrogen (including the presence of oxygen deficient atmospheres in working areas ) and initiate shutdown 3 atmospheres in working areas 4), initiate forced ventilation, actions thus minimizing the duration of releases, and and minimize the duration of releases; and elimination of potential ignition sources; • Implementation of confined space entry procedures as • Design of facilities and components according to applicable described in the General EHS Guidelines with industry safety standards, avoiding the placement of consideration of facility -specific hazards. oxygen-carrying piping in confined spaces, using intrinsically safe electrical installations, and using facility - Chemical Hazards wide oxygen venting systems that properly consider the Chemical exposures in natural gas processing facilities are potential impact of the vented gas; mainly related to carbon monoxide and methanol releases. • Implementation of hot work and permit-required confined Potential inhalation exposures to chemicals emi ssions during space entry procedures that specifically take into account routine plant operations should be managed based on the the potential release of oxygen; results of a job safety analysis and industrial hygiene survey and • Implementation of good housekeeping practices to avoid according to the occupational health and safety guidance accumulation of combustible materials; provided in the General EHS Guidelines. Protection measures include worker training, work permit systems, use of personal • Planning and implementation of emergency preparedness protective equipment (PPE), and toxic gas detection systems and response plans that specifically incorporate with alarms. procedures for managing uncontrolled releases of oxygen; and Fire and Explosions • Provision of appropriate fire prevention and control Fire and explosion hazards generated by process operations equipment as described below (Fire and Explosion include the accidental release of Syn-gas (containing carbon Hazards). monoxide and hydrogen), oxygen, and methanol. High pressure Syn-gas releases may cause “Jet Fires” or give rise to a Vapor Oxygen-Deficient Atmosphere Cloud Explosion (VCE), “Fireball,” or “Flash Fire,” depending on The potential releases and accumulation of nitrogen gas into the quantity of flammable material involved and the degree of work areas can result asphyxiating conditions due to the confinement of the cloud. Hydrogen, methane, and carbon displacement of oxygen by these gases. Prevention and control monoxide gases may ignite even in the absence of ignition measures to reduce risks of asphyxiant gas release include: sources if their temperatures exceed their auto-ignition points of • Design and placement of nitrogen venting systems 500°C, 580°C, and 609°C, respectively. Flammable liquid spills according to recognized industry standards; may cause “Pool Fires.” 3 Working areas with the potential for oxygen enriched atmospheres should be 4 Working areas with the potential for oxygen deficient atmospheres should be equipped with area monitoring systems capable of detecting such conditions. equipped with area monitoring systems capable of detecting such conditions. Workers also should be equipped with personal monitoring systems. Both types Workers also should be equipped with personal monitoring systems. Both types of monitoring systems should be equipped with a warning alarm set at 23.5 of monitoring systems should be equipped with a warning alarm set at 19.5% percent concentration of O2 in air. concentration of O2 in air. APRIL 30, 2007 8 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP Recommended measures to prevent and control fire and o Designing the oily sewage system to avoid explosion risks from process operations include the following: propagation of fire. • Providing early release detection, such as pressure 1.3 Community Health and Safety monitoring of gas and liquid conveyance systems, in The most significant community health and safety hazards addition to smoke and heat detection for fires; associated with natural gas processing facilities occur during the • Limiting the inventory that may be released by isolation of operation phase and may include the threat from major the process operations in the facility from large storage accidents related to the aforementioned fires and explosions at inventories; the facility and potential accidental releases of raw materials or • Avoiding potential sources of ignition (e.g., by configuring finished products during their transport outside of the processing the layout of piping to avoid spills over high temperature facility. Guidance for the management of these issues is piping, equipment, and / or rotating machines); presented under the Major Hazards section below and in • Controlling the potential effect of fires or explosions by relevant sections of the General EHS Guidelines including the segregation of process, storage, utility, and safe areas by sections on: Traffic Safety , Transport of Hazardous Materials, designing, constructing, and operating them according to and Emergency Preparedness and Response. international standards5 for the prevention and control of fire and explosion hazards, including provisions for Additional relevant guidance applicable to the transport by sea distances between tanks in the facility and between the and rail as well as shore-based facilities can be found in the facility and adjacent buildings, provision of additional EHS Guidelines for Shipping, Railways, Ports and Harbors, and cooling water capacity for adjacent tanks, or other risk- Crude Oil and Petroleum Products Terminals. based management approaches; 6 and • Limiting the areas that may be potentially affected by accidental releases by: o Defining fire zones and equipping them with a drainage system to collect and convey accidental releases of flammable liquids to a safe containment area including secondary containment of storage tanks; o Installing fire / blast partition walls in areas where appropriate separation distances cannot be achieved; and 5 Further guidance to minimize exposure to static electricity and lightening is available in API Recommended Practice 2003: Protection Against Ignitions Arising Out of Static, Lightning, and Stray Currents (1998). 6 Safety distances also can be derived from industry and trade association standards, insurance providers, and specific safety analyses. APRIL 30, 2007 9 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP 2.0 Performance Indicators and Environmental Monitoring Monitoring Environmental monitoring programs for this sector should be implemented to address all activities that have been identified to 2.1 Environment have potentially significant impacts on the environment, during normal operations and upset conditions. Environmental Emissions and Effluent Guidelines monitoring activities should be based on direct or indirect Tables 1 and 2 present process emission and effluent guidelines indicators of emissions, effluents, and resource use applicable for this sector. Guideline values for process emissions and to the particular project. effluents in this sector are indicative of good international industry practice as reflected in relevant standards of countries Monitoring frequency should be sufficient to provide with recognized regulatory frameworks. These guidelines are representative data for the parameter being monitored. achievable under normal operating conditions in appropriately Monitoring should be conducted by trained individuals following designed and operated facilities through the application of monitoring and record-keeping procedures and using properly pollution prevention and control techniques discussed in the calibrated and maintained equipment. Monitoring data should be preceding sections of this document. Combustion source analyzed and reviewed at regular intervals and compared with emissions guidelines associated with steam- and power- the operating standards so that any necessary corrective generation activities from sources with a capacity equal to or actions can be taken. Additional guidance on applicable lower than 50 MWth are addressed in the General EHS sampling and analytical methods for emissions and effluents is Guidelines with larger power source emissions addressed in provided in the General EHS Guidelines. the EHS Guidelines for Thermal Power. Guidance on ambient considerations based on the total load of emissions is provided Table 1. Air Emissions Levels for Natural Gas in the General EHS Guidelines. Processing Facilitiesa Effluent guidelines are applicable for direct discharges of treated Pollutant Units Guideline Value effluents to surface waters for general use. Site-specific 150b NOX mg/Nm 3 50c discharge levels may be established based on the availability SO 2 mg/Nm 3 75 and conditions in the use of publicly operated sewage collection Particulate Matter mg/Nm 3 10 (PM10) and treatment systems or, if discharged directly to surface VOC mg/Nm 3 150 waters, on the receiving water use classification as described in CO mg/Nm 3 100 the General EHS Guidelines. These levels should be achieved, a. Dry gas at 15% oxygen b. The 150 mg/NM3 NOX value is applicable to facilities with a total heat without dilution, at least 95 percent of the time that the plant or input capacity of up to 300 MWth. c. The 50 mg/NM 3 NOX value is applicable to facilities with a total heat unit is operating, to be calculated as a proportion of annual input capacity greater than 300 MWth. operating hours. Deviation from these levels in consideration of specific, local project conditions should be justified in the environmental assessment. APRIL 30, 2007 10 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP States (OSHA),9 Indicative Occupational Exposure Limit Values Table 2. Effluents Levels for Natural Gas Processing Facilities published by European Union member states, 10 or other similar sources. Guideline Pollutant Units Value pH -- 6-9 Accident and Fatality Rates BOD 5 mg/l 50 Projects should try to reduce the number of accidents among COD mg/l 150 project workers (whether directly employed or subcontracted) to TSS mg/l 50 a rate of zero, especially accidents that could result in lost work Oil and Grease mg/l 10 time, different levels of disability, or even fatalities. Facility rates Cadmium mg/l 0.1 may be benchmarked against the performance of facilities in this Total Residual Chlorine mg/l 0.2 Chromium (total) mg/l 0.5 sector in developed countries through consultation with Copper mg/l 0.5 published sources (e.g. US Bureau of Labor Statistics and UK Iron mg/l 3 Health and Safety Executive)11. Zinc mg/l 1 Cyanide Occupational Health and Safety Monitoring Free mg/l 0.1 Total 1 The working environment should be monitored for occupational Lead mg/l 0.1 hazards relevant to the specific project. Monitoring should be Nickel mg/l 1.5 designed and implemented by accredited professionals 12 as Heavy metals total mg/l 5 part of an occupational health and safety monitoring program. Phenol mg/l 0.5 Facilities should also maintain a record of occupational Nitrogen mg/l 40 Phosphorous mg/l 3 accidents and diseases and dangerous occurrences and accidents. Additional guidance on occupational health and 2.2 Occupational Health and Safety safety monitoring programs is provided in the General EHS Guidelines. Occupational Health and Safety Guidelines Occupational health and safety performance should be evaluated against internationally published exposure guidelines, of which examples include the Threshold Limit Value (TLV®) occupational exposure guidelines and Biological Exposure Indices (BEIs®) published by American Conference of Governmenta l Industrial Hygienists (ACGIH), 7 the Pocket Guide to Chemical Hazards published by the United States National Institute for Occupational Health and Safety (NIOSH),8 9 Available at: http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDAR Permissible Exposure Limits (PELs) published by the DS&p_id=9992 10 Available at: http://europe.osha.eu.int/good_practice/risks/ds/oel/ Occupational Safety and Health Administration of the United 11 Available at: http://www.bls.gov/iif/ and http://www.hse.gov.uk/statistics/index.htm 12 Accredited professionals may include Certified Industrial Hygienists, 7 Available at: http://www.acgih.org/TLV/ and http://www.acgih.org/store/ Registered Occupational Hygienists, or Certified Safety Professionals or their 8 Available at: http://www.cdc.gov/niosh/npg/ equivalent. APRIL 30, 2007 11 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP 3.0 References and Additional Sources Compressed Gas Association Inc. (CGA). 2001. CGA G-4.6, Oxygen World Bank Group. 2004. A Voluntary Standard for Global Gas Flaring and Compressor Installation and Operation Guide. First Edition. Arlington, VA: CGA. Venting Reduction. Global Gas Flaring Reduction (GGFR) Public-Private Available at http://www.cganet.com/ Partnership, Report No. 4. Washington, DC: World Bank. Available at http://siteresources.worldbank.org/INTGGFR/Resources/gfrmethodologyno6revi European Commission. 2003. European Integrated Pollution Prevention and sed.pdf Control Bureau (EIPPCB). BAT Techniques Reference (BREF) Document on Mineral Oil and Gas Refineries. EIPPCB: Sevilla, Spain. Available at http://eippcb.jrc.es/pages/FActivities.htm European Industrial Gases Association (EIGA). 2002. Oxygen Pipeline Systems. IGC Document 13/02/E. Brussels: EIGA. European Industrial Gases Association. 2001 Centrifugal Compressor for Oxygen Service. Code of Practice. IGC Document 27/01/E. Brussels: EIGA. European Industrial Gases Association (EIGA). 1999. Safe Operation of Reboilers/Condensers in Air Separation Units. IGC Document 65/99/EFD. Brussels: EIGA. German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU). 2004. Promulgation of the New Version of the Ordinance on Requirements for the Discharge of Waste Water into Waters (Waste Water Ordinance - AbwV) of 17. June 2004. Berlin: BMU. Available at http://www.bmu.de/english/publication/current/publ/5258.php German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU). 2002. First General Administrative Regulation Pertaining to the Federal Emission Control Act (Technical Instructions on Air Quality Control – TA Luft). Berlin: BMU. Available at http://www.bmu.de/english/air_pollution_control/ta_luft/doc/36958.php Schmidt, W.P. , K.S. Winegardner, M. Dennehy and H. Casle-Smith. 2001. Safe Design and Operation of a Cryogenic Air Separation Unit. Process Safety Progress (Vol. 20. No.4) pages 269-278, December 2001. United States (US) Environmental Protection Agency (EPA). 1987. 40 CFR Part 60. Standards of Performance for New Stationary Sources. Subpart Kb— Standards of Performance for Volatile Organic Liquid Storage Vessels (Including Petroleum Liquid Storage Vessels) for Which Construction, Reconstruction, or Modification Commenced after July 23, 1984. Washington, DC: US EPA. US EPA. 40 CFR Part 60. Standards of Performance for New Stationary Sources. Subpart QQQ—Standards of Performance for VOC Emissions From Petroleum Refinery Wastewater Systems. Washington, DC: US EPA. US EPA. 40 CFR Part 63. National Emissions Standards for Hazardhous Air Pollutants. Subpart CC—National Emission Standards for Hazardous Air Pollutants from Petroleum Refineries. Washington, DC: US EPA. US EPA. 40 CFR Part 63. . National Emissions Standards for Hazardhous Air Pollutants. Subpart HHH—National Emission Standards for Hazardous Air Pollutants From Natural Gas Transmission and Storage Facilities. Washington, DC: US EPA. US EPA. 40 CFR Part 63. . National Emissions Standards for Hazardhous Air Pollutants. Subpart VV—National Emission Standards for Oil-Water Separators and Organic-Water Separators. Washington, DC: US EPA. APRIL 30, 2007 12 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP Annex A: General Description of Industry Activities For the purposes of these EHS Guidelines, natural gas normally consists of a reforming section followed by a heat processing refers to the production of liquid products from recovery section. natural gas. These facilities first produce syn-gas through the The reforming section comprises a pre-reforming reactor Natural Gas Reforming. Syn-gas is then converted into liquid followed by an autothermal reforming reactor. The pre-reforming petroleum products (GTL products), which may include naphtha, reactor uses a steam reaction to convert the heavier gasoline, kerosene, diesel fuel, waxes, and lubes, or into hydrocarbons (e.g. ethane, propane) into hydrogen and carbon methanol through methanol synthesis. monoxide, to avoid the formation of soot in the autothermal Natural gas feedstock is typically purified (e.g., de-sulfurized) reforming reactor. In the autothermal reforming reactor, and fractionated from heavy hydrocarbons in natural gas methane reacts with steam and oxygen at about 950°C and 30- treatment facilities, as discussed in the EHS Guidelines for Oil 40 bar in the presence of a nickel-based catalyst to yield a and Gas Development (Onshore and Offshore). Natural gas mixture of carbon monoxide and hydrogen in the desired molar processing facilities are capital-intensive operations, and are ratio. typically located in natural gas producing regions. Production In the heat recovery section, the reaction heat from the capacities for GTL plants are typically in the range of 20,000 to autothermal reforming reactor is reused to pre-heat process 30,000 barrels per stream day (BPSD) of GTL products, while streams, in addition to producing high pressure steam for use in capacities of 50,000 to 100,000 BPSD are under evaluation. the steam turbines and to feed the pre-reforming and the Methanol plants with a capacity of 5,000 metric tons per day autothermal reforming reactors. Cold gas leaving the heat (MTPD) are currently in operation, and facilities for higher recovery section enters a carbon dioxide removal stage, production volumes (e.g., up to 7,500-10,000 MTPD), are under normally based on a regenerative alkaline washing, before evaluation. being fed into the Fischer-Tropsch Synthesis Unit. Oxygen is GTL Production provided by a dedicated Air Separation Unit (ASU), which also GTL production plants typically comprise the following process supplies the plant with the necessary service nitrogen. units: Fischer-Tropsch Synthesis Unit • Synthetic Gas Production Unit The syn-gas from the Syn-gas Production Unit then enters the • Fischer-Tropsch Synthesis Unit Fischer-Tropsch Synthesis Unit, which principally comprises • Product Up-grading Unit reaction, stabilization, and gas recycling sections. • Air Separation Unit (ASU) In the reaction section, carbon monoxide and hydrogen react as part of the Fischer-Tropsch synthesis reaction, at about 250°C Synthetic Gas Production Unit and 20-25 bar over iron or cobalt- based catalysts, to yield long- Natural gas feedstock is treated to remove trace quantities of chain hydrocarbons, water, oxygenated compounds (mainly sulfur (e.g., by passing the gas over zinc oxide beds) before alcohols), organic acids, and minor amounts of ketones. The being fed into the Synthetic (Syn) Gas Production Unit. This unit commercially available Fischer-Tropsch reactors include Fixed APRIL 30, 2007 13 Environmental, Health, and Safety Guidelines NATURAL GAS PROCESSING WORLD BANK GROUP Bed Tubular type and Fluidized Bed or Slurry type. In the described for GTL plants. In the steam reforming furnace the stabilization section, the unconverted gas and the light- ends are gas reacts with steam at about 800°C and 40-50 bar in the separated and the unconverted gas is subsequently recycled presence of a nickel-based catalyst. back to the Fischer-Tropsch Synthesis Section. In the heat recovery section, the reaction heat, generated in the The stabilized Fischer-Tropsch product enters the product up- autothermal reforming reactor, is used to pre-heat process grading unit, generally a mild hydrocracker, where under streams and to produce high pressure steam to operate steam platinum or palladium catalyst, the long chain hydrocarbons are turbines and to feed all reforming reactors. Oxygen is again transformed into the desired end products (e.g., naphtha, provided by a dedicated Air Separation Unit (ASU), which also gasoline, kerosene, diesel fuel, waxes, and lubes). The supplies with the service nitrogen. hydrogen necessary for the mild hydrocracker is produced by a dedicated hydrogen production process typically involving a Methanol Synthesis Unit natural gas steam reforming unit. The Methanol Synthesis Unit principally comprises reaction, gas recycle, and methanol purification sections. The utilities necessary to run the plant are mainly electric power, steam and cooling water. Nitrogen is provided by the Air In the reaction section, carbon monoxide and hydrogen react at Separation Unit. The plants are provided with a blow-down and about 250°C and 50-80 bar in the presence of a copper-based a flare. These plants are normally fitted with large storage tank catalyst to yield methanol. The commercially available reactors farms to collect the products, as well as ship loading facilities are of Fixed Bed Tubular or Multi-Beds Adiabatic Radial types. and / or pipelines to dispatch the products, similarly to refineries Down-stream of the reactor, methanol is condensed and the and other downstream petroleum facilities. More detailed unconverted gas is recycled to the Syn-gas Production Unit. information is provided in the EHS Guidelines for Crude Oil and The purification section is composed of two fractionation towers Petroleum Product Terminals. where both light- ends and heavy-ends (high molecular weight alcohols) are removed from methanol product. The light-ends Methanol Production are normally recovered as fuel gas, while the heavy-ends are Methanol production plants comprise Syn-gas production, normally burned in a steam boiler with a dedicated burner. The methanol synthesis, and air separation units. utilities necessary to run methanol plants are the same as Syn-gas Production Unit needed for GTL plants. The plants are provided with a blow- This unit is similar to the unit as described above for GTL plants. down and a flare, and normally include large methanol storage For capacities in excess of 5,000 MTPD, the trend is to adopt tanks. only the autothermal reformer. Existing medium-size plants with capacities up to 5,000 MTPD make use of combined reforming. The combined reforming involves a pre-reforming reactor followed by a steam reforming furnace and, finally, an autothermal reforming reactor. The pre-reforming and the autothermal reforming reactors have the same functions as APRIL 30, 2007 14