PTGL processes

One possible system which could be used by smaller communities is to combine source separation of solid waste with a simple PTGL process for energy conversion of the paper fraction of the waste. Since typical solid waste contains over 40, percent paper, energy recovery from the paper fraction could reduce landfill requirements by the same amount. 

TABLE 1 b PTGL - Processes for industrial wastes and tires. 

PTGL-processes (table Ia,b,c) can be characterized by their operating principle (pyrolysis, gasification or liquefaction) and reaction conditions, their type of reactor and method of heat supply and the possible presence of auxiliary systems. The selection of a particular process will ultimately be based on its proven reliability on one hand and on the quality of the process output on the other [ ]. ... 

The only PTGL-process currently operating at a commercial scale is the American-developed Andco-Torrax process, pioneered in Europe by S.A. Ets Paul Wurth (Luxemburg). Since its start-up in 1976 the Leudelange plant has operated intermittently, the frequent periods of shutdovn being used for modifying various parts of the system. At present the reliability of the process has considerably improved but the nominal design capacity (200 t/day) vill probably not be attained. [ 6]. ... 

From European experience it can be concluded that the Andco-Torrax system is a feasible PTGL-process but that it takes much time and trouble before such a new process can be operated with a sufficient degree of reliability. It is still too early to compare the process to conventional mass-incineration. At present the consumption of auxiliary fuel is still very high at 5 to 12 GJ/h (Luxemburg). The power consumption, at 60 - 80 kWh/t of refuse is about twice that of a conventional incinerator. The consumption of cooling water and the composition of the flue gas are roughly comparable. 

The pyrolysis of cellulose is of outstanding importance in the study of PTGL-processes involving refuse, wood waste or agricultural waste. Unfortunately the products and mechanism of thermal decomposition are extremely sensitive to a number of physical and chemical factors. Even the decomposition of the purest a-cellulose has led to conflicting opinions regarding kinetics and mechanism[ 3j. 

The aim of this paper is to describe the present status of development and application, and evaluation of PTGL processes in our country. 

Application of PTGL Processes as an Alternative to Incineration for Treatment of MR. As stated above, as a first stage, various PTGL process systems offer the possibility of decreasing several pollution problems caused in the incineration process. 

While the topic of this paper is Canada s PTGL (Pyrolysis Thermal Gasification and Liquefaction) research program it is useful to review the current status of conversion technologies for biomass. The goal is to describe the characteristics of each technology so that efficiencies, process steps and environmental factors are well quantified and under these circumstances for a known cost and nature of feedstock an economic or social decision can be taken as to whether or not to implement the technology. 

PTGL-technology can only be succesful if practical solutions are found for problems such as refuse handling and feeding, maintenance of stable operating conditions with a constantly variable feedstock, smooth elimination of residue and proper treatment of reaction products. Quite normally process developers center all their energy on the design,construction and demonstration of their plant and equipment. 

On the basis of these circumstances, the need for a better solid waste disposal system has stimulated a great deal of interest in the application of pyrolysis to solid wastes instead of the traditional incineration system in our country. Since the Agency of Industrial Science Technology, MITI had launched the national project on development of technology and system of resource recovery from refuse in 1973, more than a dozen processes of PTGL are being developed at the national level, municipal level, and the level of private companies as shown in Table I. 

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