PERC process

The aqueous-phase pyrolysis can also be assisted by catalysts and reactive gases. For instance, the PERC process [3, 33] produces a pyrolysis oil upon dissolving wood chips in a recycle pyrolysis oil, mixing the slurry with a water-Na2C03 solution and treating the resulting mixture at 370 °C and 275 bar under synthesis gas atmosphere. 

Statfjord atmospheric resid (1). Atmospheric resid (2). SRC II (3). Prahoe shale oil (4). Directly liquefied oil from wood chips using the PERC process (5). Molar ratio adjusted assuming that ammonia, water and hydrogen sulfide are formed by the heteroatoms. 

The oil derived from biomass was liquefied with the PERC process, extracted with decalin, hydroprocessed at 370 0, and the fraction boiling above 350 C (BMO) was separated by distillation (16). A hydroprocessed mixture of North sea and Arabian light vaccum gas oil (HVGO) was used as a "base line", i.e. a typical FCC feed stock. 

The plasma energy recycle and conversion (PERC) process is an indirectly heated ex situ thermal recycling and conversion technology. According to the vendor, it treats hazardous waste, mixed radioactive waste, medical waste, municipal solid waste, radioactive waste, environmental restoration wastes, and incinerator ash in gaseous, hquid, slurry, or solid form. The technology uses an induction-coupled plasma (ICP) torch as its heat source coupled to a reaction chamber system to destroy hazardous materials. 

The evaluation of pressurized wood-slurry liquefaction by the LBL process of wood-water slurries was performed mainly in small-scale equipment (Ergun, 1981 Davis, 1983). Oils similar to those produced by the PERC process were obtained, but at lower yields. In the late 1970s and early 1980s, the PERC process was evaluated in a PDU (Thigpen and Berry, 1982). The purpose of... 

In view of the complex nature of the reactants and products, it is likely that a complete understanding of all of the chemical reactions that occur in the PERC process will not be developed unless detailed mechanistic studies are carried out. 

Rust Engineering believes that the PDU needs modifications in order to develop the PERC process. However, a great deal of engineering design and materials compatability information has been accumulated which will be useful in designing future biomass liquefaction facilities. 

With the informations drawn from our experimental work, a preliminary conceptual design has been developed. Then, we used the same assumptions as proposed by SRI, which published a rough economical analysis of the PERC Process (8), in order to perform also economical analysis of a two steps liquefaction process. 

Perc A process for making a heavy fuel oil by reacting a slurry of biomass in aqueous sodium carbonate solution with carbon monoxide. Under development in the United States in 1980. 

The vendor claims that a PERC system typically costs between 200,000 and 1,000,000 for a test nnit and between 500,000 and over 20,000,000 for a large processing facility (D160112, p. 3). 

Pilot plant and demonstration plant scale projects include the SYNTHANE process, the Hygas process, and the Bigas process among others. See W. P. Haynes and A. J. Forney, High BTU Gas from Coal Status and Prospects, Tech. Rep. PERC/IC-76-1. U.S.E.R. D.A. Office of Public Affairs, 1976. 

Since the 1960s, the prevailing solvent at the 36,000 dry cleaning establishments in the United States has been perchloroethylene (also called perc or PCE) (USEPA, 1998). Process improvements implemented in the dry cleaning industry have greatly reduced perc usage in recent years, but annual consumption is approximately 53 million kg (Mannsville, 1997). 

Dry cleaning customers and employees of dry cleaning plants often complain about the chemical odor of perchloroethylene. More recently, with the recent process changes to reduce perc consumption and emission to the atmosphere, solvent turnover is minimized and complaints have arisen about a stale, stagnant and unpleasant odor that the customer relates to as clothes being cleaned in a dirty solvent (ISFA, 1999). Carbon dioxide dry cleaning clearly has an advantage here in that C02 is odorless. 

Petrusic WM. Semantic congruity effects and theories of the comparison process. J Exp Psychol Hum Perc Perf 1992 18 962-986. 

A few properties of the liquid oils produced by selected flash pyrolysis and the PERC and LBL processes are listed in Table 8.13. It as apparent that there are some basic differences between the two classes of oils. The oils from the flash pyrolysis processes are quite similar, as are the oils from the PERC and LBL processes. But there are major differences in their elemental analyses and... 

Dry cleaning is a process in which clothes are cleaned without water. The cleaning fluid used is either perchlorethylene (C12C=CC12) perc or the volatile synthetic solvent carbon tetrachloride (CC14). These solvents are used because their molecular structures are similar to those of the oils found in dirt and grime. 

The process development activities based on the original PERC flowsheet have been beset with many mechanical and operational difficulties and it has not yet been possible to obtain a pure wood derived oil which is free of the anthracene start up oil. 

The most interesting variant on the basic thermochemical liquefaction process involves the addition of an overpressure of carbon monoxide and hydrogen to the reaction, which is also performed in a non-aqueous solvent (anthracene oil or recycled product oil). Yields of oil up to 70% of the weight of the Douglas fir wood feedstock have been reported in an investigation by Elliott (4-8), Elliott and Walkup ( and Elliott and Giacoletto (10). This process variant (also known as the Albany, PERC, or CO-Steam Process) is described in more detail in the Results and Discussion section. 

In order to compare the two steps process with the PERC and the LBL ones, the three plants were costed out with the same capacity. Results are given in Table I,... 

Most of the test work has been done with two product oils from the Albany, Oregon Biomass Liquefaction Experimental Facility. Both oils were produced In an alkali-catalyzed, reducing gas environment with long residence times and high pressure (3000 psig). The TR12 represents a PERC-type recycle oil slurry process, and TR7 represents the LBL-type aqueous slurry single pass process. Detailed process descriptions (U) can be found elsewhere. 

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