Simulation of Processes for Thermal Treatment of Wastes

článek v časopise - ostatní, Jost

angličtina

A convenient software system based on modelling units for incineration and thermal treatment including utilisation of energy is a useful tool for both the designers and operators. It can be successfully used to support both the design decisions in selecting optimal arrangements and the choice of operating conditions. Software TDW for simulating the processes and/or units for thermal disposal of wastes has been created and developed for the purposes mentioned above. Using this system it is possible to calculate heat and mass balance of a process and to simulate a range of alternatives. The computer program consists of various procedures each of them representing an individual apparatus. The apparatuses are connected by streams. A model for calculation of combustion in a combustion chamber, rotary kiln etc. can be considered as a core of the system. The model consists of procedures for calculation of combustion air flowrate, composition, temperature and flowrate of flue gas, net heating value of fuel based on its composition and heat balance of the apparatus. Further procedures are those dealing with mixing flue gases and their splitting, filtration of flue gas, recycling, pre-heating combustion air and/or heating cold flue gas and other procedures related to utilising heat (i.e. models of steam generators and superheators). A complex model is completed with procedures of scrubber treatment and adsorption. Software TDW based on the model described above can be used and run under Windows thus it is a user-friendly product. A design of a process/unit consists in drawing a flowsheet with individual apparatuses and streams which connect them. A new flowsheet can be generated and/or a previously generated one can be read and re-drawn. We can remove or add new pieces of equipment or create a new alternative of a unit. A flowsheet obtained by using TDW is similar as that obtained with the aid of other simulation software generally used in the field of chemical engineering (e.g. ChemCAD, AspenPlus). When the flowsheet generation is completed input data for all the pieces of equipment have to be specified. Then the computer program can be run. Since the mathematical models of individual apparatuses are not complicated ones results of a simulation can be obtained immmediately even if recycling streams are considered and thus an iterational algorithm is necessary to be used. The main results of a simulation are as follows: heat and mass balance for all pieces of equipment, detailed process stream data (temperature, pressure, mass and volumetric flowrates, composition). Based on these data a design of a unit can be made (dimensions of equipment, piping etc.) and/or changing parameters in a regime of operation. Simulation of an industrial unit for the thermal disposal of both solid and liquid wastes is shown as an instructive example of the benefit of using software TDW. Various alternatives are considered and an evaluation is made.

software, simulation, thermal treatment

STEHLÍK, P.; PUCHÝŘ, R.; ORAL, J.

1. 1. 2000

0956-053X

Waste Management

20

5-6

Spojené státy americké

435

442

8