Emission control problems

Fluid catalytic cracking units present formidable emission control problems. Contaminants are present in both reactor product gas and regenerator flue gas. The reactor product contains hydrogen sulfide, ammonia, and cyanides, plus combined sulfur and nitrogen in the liquid products. Hydrogen sulfide, ammonia and cyanides are handled as part of the overall refinery waste water cleanup. The combined sulfur and nitrogen may be removed by hydrotreating. 

Emission control problems and experiences with the VD 1 Guidelines 3471 in Germany... 

Losses of phosphoric acid mists or phosphorus pentoxide fumes through a corrosion-induced rupture of ductwork or a vessel, or from a process-related parameter, represent the most commonly experienced emission control problems with furnace acid plants. When this occurs, a white plume, or ghost, of aerosol droplets or particles remains visible downwind long after the steam component has dissipated. Corrosion problems are now better understood so that more exposed components are constructed of stainless steel. If high temperatures are also involved, the equipment is lined with graphite [28]. 

Similarities of raw materials and many of the procedures of distillery operations to those of brewing and winemaking mean that many of the emission control problems and solutions are similar. Much of the discussion of those sections is also appropriate here. 

Specialized designs have been developed to solve emission control problems connected with conventional methods in the pharmaceutical industry. Among these is closed-cycle drying, which anploys recycle of the drying medium. Closed-cycle drying is recommended if... 

Automotive Emission Control Catalysts. Air pollution (qv) problems caused by automotive exhaust emissions have been met in part by automotive emission control catalysts (autocatalysts) containing PGMs. In the United States, all new cars have been requited to have autocatalyst systems since 1975. In 1995, systems were available for control of emissions from both petrol and diesel vehicles (see Exhaust control, automotive). 

Many industries operated throughout the world do not fall into the previous categories. Some of these are universal, such as asphalt batching plants, whereas others are regional, such as bagasse-fired boilers. Each has its own emission and control problems and requires knowledgeable analysis and engineering. Some of the more widely used processes are examined in this section. 

Indoor air contaminants can originate within the building or be drawn in from outdoors. If contaminant sources are not controlled, problems can arise, even if the HVAC system is properly designed and well-maintained. Sources can be from outside the building from operating equipment, from human activities, and other or miscellaneous sources. Sources outside a building include contaminated outdoor air, emissions from nearby sources, soil gas, or moisture or standing water. 

It was not nndl the 1950s that detonation flame arresters made of crimped metal ribbon elements were developed and began to be used more freqnendy (Binks 1999). The major impetus for die use of crimped metal ribbon detonation flame arresters in the US was the enactment of clean air legislation (Clean Air Act of 1990) which inadvertently created a safety problem by requiring reductions in volatile organic compound (VOC) emissions. To do this, manifolded vent systems (vapor collection systems) were increasingly installed in many chemical process industry plants which captured VOC vapors and transported them to suitable recovery, recycle, or destruction systems. This emission control requirement has led to the introdnction of ignition risks, for example, from a flare or via spontaneous combustion of an activated carbon adsorber bed. Multiple... 

See also Acid Ram Air Quality, Indoor Atmosphere Automobile Performance Climatic Effects Emission Control, Vehicle Emission Control, Power Plant Environmental Economics Environmental Problems and Energy Use Gasoline and Additives Transportation, Evolution of Energy Use and Turbines, Gas. 

See also Batteries Capacitors and Ultracapacitors Electric Motor Systems Emission Control, Vehicle Environmental Problems and Energy Use Flywheels Fuel Cells Fuel Cell Vehicles Flybrid Vehicles Materials Transportation, Evolution ofEnergy Use and. 

Croezen and Sas (a.4) have published an extensive LCA for treatment of MPW with the Texaco process. There is a detailed discussion on inputs and emissions there. No specific problems with emissions control were mentioned by these authors. As for cost performance, detailed data of the cost structure have not been made public. The general figure circulating for the likely gate fee of the Texaco process is 90 to 135 per tonne for a 50 ktonne/year plant, decreasing to 50/tonne for a 200 ktonne/year plant. 

The final emission standard under the BIF regulations limits the unit s output of HCI and chlorine gas (Cl j). These compounds combine with water in the air to form acid rain. They are also a known cause of human respiratory problems. The emission controls are implemented in the same way as the metal emissions, using the tiered approach. The owner/operator has a choice of three tiers with varying focal points. The Tier I and Tier II screening levels for waste feed and stack emission limits are located in Part 266, Appendices II and III.5... 

These toxic components sometimes travel more than a thousand kilometers and cause problems in other places and, in some cases, in other countries. Therefore the problem of air pollution attracts worldwide attention. Among these, the coal-fired flue gas from thermal power plants has been recognized as one of the main sources of environmental pollution, because of its larger amount of 8 and N components. Now many countries are introducing stricter emission control regulations to solve the problem. 

Despite the fact that organic pollution still remains a problem, the steps taken to improve the situation cannot be overlooked. Specifically, the improvement in both wastewater treatment and emission controls has led to a significant decrease in the percentage of heavily polluted rivers, from 24% in the late 1970s to 6% in the 1990s in Western Europe. In contrast, the situation is not exactly the same in the southern member states, since 50% of the population is not yet connected to sewage treatment operations. 

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