Energy recovery equipment

I he direct-flame incinerator is the simplest type of thermal oxidation system. It comprises a combustion chamber and supplementarv fuel-injection system with no energy-recovery equipment. Direct-flame incineration is suitable only for gases that support combustion without requirements for auxiliary fuel (concentrated streams) or for intermittent use. 

Incineration is another form of energy recovery [ 1 ]. Some hazardous waste incinerators and many refuse incinerators are equipped with energy recovery equipment. While some major facilities operate either or both types of incinerators, most firms must resort to offsite treatment. These treatment facilities should be carefully evaluated from an economic, regulatory, and operations standpoint. While these facilities reduce volume and, generally, toxicity, air pollutant generation and the final incinerator ash disposal must still be considered and may impact a generator s liability. 

Recovery of a portion of the heat energy available in the hot (>2000°F) syngas stream of the 25 TPD unit is intended to improve the net thermal efficiency of the process by installing a waste heat boiler, which will produce steam for use in process heating. In a larger gasification system, additional energy recovery equipment could be installed to further improve efficiency. However, the capital costs of such equipment are not justified for a small 25 TPD pilot unit. 

A further study, recently completed by TNO (the Dutch engineering, testing and scientific organisation) has concluded that the presence of bromine in plastics (as a flame retardant) does not adversely affect energy recovery equipment for household waste treatment. Levels of bromine in the plastic waste going to energy recovery can be easily increased by a factor of 9-10 times before any additional adverse effect could occur in the equipment. 

Thermal and catalytic incinerators, condensers, and adsorbers are the most common methods of abatement used, due to their ability to deal with a wide variety of emissions of organic compounds. The selection between destruction and recovery equipment is normally based on the feasibility of recovery, which relates directly to the cost and the concentration of organic compounds in the gas stream. The selection of a suitable technology depends on environmental and economical aspects, energy demand, and ease of installation as well as considerations of operating and maintenance. 7 he selection criteria may vary with companies or with individual process units however, the fundamental approach is the same. 

As liquids are essentially incompressible, less energy is stored in a compressed liquid than a gas. However, it is worth considering power recovery from high-pressure liquid streams (> 15 bar) as the equipment required is relatively simple and inexpensive. Centrifugal pumps are used as expanders and are often coupled directly to pumps. The design, operation and cost of energy recovery from high-pressure liquid streams is discussed by Jenett (1968), Chada (1984) and Buse (1985). 

Such improvements could for instance be looked for in the handling and pretreatment of solid feedstock, which require heavy and energy consuming equipment. Purification of the product can also be capital intensive. For instance, hydrolysis and fermentation technologies often result in a product that is highly diluted in water and requires expensive recovery by distillation or extraction. 

CMCs are used in the manufacture of preheaters and recuperators in heat recovery equipment. They are used for indirect heating and energy-intensive industrial internal processes such as glass melters, steel reheaters and aluminium remelters. 

The permeate of the MF units is fed to two SWRO units equipped with high-pressure pumps with an energy-recovery system (Pelton wheel). The SWRO units comprise 44 pressure vessels loaded with 6 Dow/FilmTec SW30 membranes each. The designed permeate capacity of each unit is 210 m3/h per unit with a recovery of 50-5 5%. Antisealant is dosed to the feed stream of the SWRO with a concentration of 3 to 4 ppm [15]. 

Heat pipes are particularly useful in energy-conservation equipment. One example is shown in Fig. 12-22 where hot exhaust gases are used to drive a waste heat recovery boiler. The hot gases from a combustion process, which... 

A. Homung, W. Koch and H. Seifert, Haloclean and PYDRA - a dual staged pyrolysis plant for the recycling waste electronic and electrical equipment (WEEE). Metals and Energy Recovery, International Symposium, Skelleftea, Sweden, 25-26 June 2003. 

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