Incineration process design

Tillman, D.A., W.R. Seeker, D. W. Pershing and D. DiAntonio. 1991. Developing Incineration Process Designs and Remediation Projects from Treatability Studies," Remediation, Summer. 

Raw material usages per ton of carbon disulfide are approximately 310 m of methane, or equivalent volume of other hydrocarbon gas, and 0.86—0.92 ton of sulfur (87,88), which includes typical Claus sulfur recovery efficiency. Fuel usage, as natural gas, is about 180 m /ton carbon disulfide excluding the fuel gas assist for the incinerator or flare. The process is a net generator of steam the amount depends on process design considerations. 

In the feed pretreatment section oil and water are removed from the recovered or converted CCI2F2. The reactor type will be a multi-tubular fixed bed reactor because of the exothermic reaction (standard heat of reaction -150 kJ/mol). After the reactor the acids are selectively removed and collected as products of the reaction. In the light removal section the CFCs are condensed and the excess hydrogen is separated and recycled. The product CH2F2 is separated from the waste such as other CFCs produced and unconverted CCI2F2. The waste will be catalytically converted or incinerated. A preliminary process design has shown that such a CFC-destruction process would be both technically and economically feasible. 

The HRUBOUT process is a mobile in situ or ex situ thermal desorption process designed to remediate soils contaminated with volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs). For the ex situ process, excavated soil is treated in a soil pile or in a specially designed container. Heated compressed air is injected into the soil, evaporating soil moisture and removing volatile and semivolatUe contaminants. Heavier hydrocarbons are oxidized as the soil temperature is increased to higher levels over an extended period of time. The vapor is collected and transferred to a thermal oxidizer (incinerator) for destruction. 

Incinerators are designed to bum and, in many cases, destroy waste materials which may sometimes be contaminated with hazardous substances. The waste materials usually have some heating value. However, nearly all incineration processes require a substantial amount of auxiliary heat which is commonly generated by the combustion of hydrocarbon fuels such as natural gas or oil. Most combustion processes use air as the oxidant. In many cases, these processes can be enhanced by using an oxidant that contains a higher proportion of 02 than that in air (see Chapter 1). 

The second case to be considered is designing a new incineration process to include oxygen enhancement. The savings in capital equipment may be very substantial. The incinerator itself can be smaller, for a fixed processing rate, compared with an air/fuel system. The associated downstream equipment may be smaller as well. 

In addition to APCD, metal emissions from waste combustors can be minimized by 1) limiting the metal content of the waste feed via source control 2) designing and operating the combustion process to minimize metal vaporization and 3) designing and operating the primary combustion chamber to minimize fly-ash carryover. From a practical standpoint, the second method is likely to be the most difficult to implement because the objective of the incineration process is to burn all the combustible waste completely and avoid PIC formation, both of which require the use of high temperatures. Therefore, the most-reliable methods of limiting metal emissions are source control and efficient use of APCD. 

In fiscal year 1981, the Army planned to build a disposal facility on Johnston Island, which would use the reverse assembly and incineration process to destroy chemical weapons stored on the island. Although the Army designed the Johnston disposal facility to destroy all types of munitions, it initially planned to equip the facility to destroy only one type of chemical munitions—the M55 rocket. Determining that the M55 rockets were in poor condition and were no longer militarily useful, the Army established an M55 rocket disposal program to destroy the nerve-agent-filled rockets stored at Johnston Island and five chemical storage sites in the continental United States. 

Incinerators are designed to heat the dryer exhaust for proper time and temperature required to decompose hydrocarbons into carbon dioxide and water through the process of oxidation. Temperature, time, and turbulence are the three factors contributing to the conversion efficiency. Thermal and catalytic incinerators are the two major incinerators in use. Thermal incinerations are used for the solvent vapor concentration around or below 25% LEL, while catalytic incinerators should be considered for applications in which there is a low concentration (below 15% LEL). 

Final disposal of the recovered agent and contaminated components is undertaken in an incinerator specifically designed and built for this purpose. The incinerator, which was built in 1980, is based on a two kiln, batch process with a secondary burner and full exhaust... 

To limit emissions, vents leaving the recovery plant pass through a VCM chemical absorption or adsorption unit, a molecular sieve, an incinerator or a catalytic treatment unit, hr the case when an incinerator is used, it must be designed and operated so as to ensure that any dioxins formed in the incineration process are destroyed and do not reform. 

Elaborate on the incineration process. What are the basic design parameters to consider in building an incineration furnace ... 

---