Design of waste gas treatment system from incinerator

Contents

Contents

Introduction

The problem of recycling solid household waste. Technologies for storage and processing of municipal solid waste

Terms of Reference

3. Calculation of pollutant emissions according to ND-

4. Determination of excess concentrations of pollutants at the NWZ boundary

5. Design of exhaust gas purification system

5. 1. General diagram

5. 2. Gas Purification System for Sulphurous Anhydride Design

5. 3. Apparatus design

5. 4. Strength calculation of the cylindrical support of the apparatus

5. 5. Calculation of vehicle support for stability

List of literature

Introduction

Today, using established technologies, humanity has a diverse structure of all kinds of waste of domestic and industrial origin. This waste, gradually accumulating, has become a real disaster. Governments in developed countries are increasingly paying attention to environmental protection and are encouraging the development of appropriate technologies. Systems for cleaning territories from garbage and technologies for burning it are developing.

Incineration reduces the amount of waste entering landfills and can be used to generate electricity. Although incineration of all waste indiscriminately is a technology of the past, modern incinerators equipped with emission treatment systems, power generators and used in combination with other MSW disposal methods can help to cope with the flow of garbage, especially in densely populated areas.

The problem of recycling solid household waste. Technologies for storage and processing of municipal solid waste

The problem of the complete destruction or partial disposal of municipal solid waste (MSW) - domestic waste - is relevant, first of all, from the point of view of negative environmental impact. Solid household waste is a rich source of secondary resources (including ferrous, non-ferrous, rare and scattered metals), as well as a "free" energy carrier, since household garbage is a renewable carbonaceous energy raw material for fuel energy. However, for any city and settlement, the problem of disposal or disposal of solid household waste is always primarily an environmental problem. It is essential that waste management processes do not undermine the ecological safety of the city, the normal functioning of the urban economy in terms of public sanitation and hygiene, as well as the living conditions of the population as a whole. As you know, the vast majority of MSW in the world is still stored in landfills, natural or specially organized in the form of "landfills." However, this is the most inefficient way to combat TBT, since landfills that occupy vast areas of often fertile land and are characterized by a high concentration of carbonaceous materials (paper, polyethylene, plastic, wood, rubber) often burn, polluting the environment with waste gases. In addition, landfills are a source of pollution of both surface and groundwater through drainage of landfills by atmospheric precipitation. Foreign experience shows that the rational organization of MSW processing makes it possible to use up to 90% of recycling products in the construction industry, for example, as concrete aggregate.

According to specialized firms currently implementing even low-potential technologies for direct combustion of solid household waste, the implementation of thermal methods when burning 1000 kg of TBT will produce thermal energy equivalent to burning 250 kg of fuel oil. However, real savings will be even greater, since they do not take into account the very fact of preserving primary raw materials and the cost of extracting them, that is, oil and obtaining fuel oil from it. In addition, in developed countries, there is a legislative restriction on the content of 1 m3 of flue gas released into the atmosphere not more than 0.1x109 g of nitrogen dioxide and furans during incineration of waste. These limitations dictate the need to search for technological ways to decontaminate MSW with the least negative impact on the environment, especially landfills. Consequently, the presence of domestic garbage in open landfills has an extremely negative impact on the environment and, as a result, on humans .

Currently, there are a number of methods of storage and processing of solid household waste, namely, pre-sorting, sanitary earth filling, incineration, biothermal composting, low-temperature pyrolysis, high-temperature pyrolysis [1].

The process of burning the waste of human life, carried out since prehistoric times, has received industrial design and is quite popular. Its disadvantages, causing a fair negative attitude of an educated and sustainable public, are:

In many enterprises that have not managed to dispose of components that are converted into harmful substances in flue gases and slag residues during incineration;

the high cost and complexity of efficient flue gas treatment, which is why simplified schemes with insufficient depth of cleaning from hazardous impurities are used, and environmental pollution occurs;

From an environmental point of view, large-scale incineration of organic waste, which distorts the natural dynamics of the circulation of substances and the balance of energy in the natural environment, which is one of the factors causing climate change, which is especially evident in the new millennium.

Thus, in the practical solution of the question of the applicability of the thermal method of processing waste of the city, it is necessary to solve at least the following problems:

• Preparation of collected municipal waste in terms of recovery of reused materials and removal of harmful substances at the stage of either collection of solid waste in residential areas, enterprises and organizations, or in special sorting areas.

• Selection of the optimal for the specific conditions of the MRZ project, ensuring efficient combustion and subsequent sufficient cleaning of flue gases, minimizing the negative impact on the environment.

Terms of Reference

The results of the analysis of emissions samples of Incinerator No. 2 (22.10.86, 23.10.86) [2] were taken as initial data.

Plant productivity - 130 thousand tons/year.

Boiler capacity for incinerated HF = 8.3 t/h.

The number of boilers is 2.

The height of the chimney is 50 m.

Pipe mouth diameter is 2.1 m.

Combustion product temperature - 220 ° С.

Ambient air temperature - 20 ° С.

Flue gas quantity - 30 m3/s.

Determination of excess concentrations of pollutants at the NWZ boundary

According to SanPiN 2.2.1 ./2.1.1.120003 "Sanitary protection zones" [6] for objects, their individual buildings and structures with technological processes, Sources of habitat and human health impacts, depending on capacity, operating conditions, nature and quantity of pollutants released into the environment, created noise, vibration and other harmful physical factors, as well as taking into account the envisaged measures to reduce their adverse impact on the habitat and human health, in accordance with the sanitary classification of enterprises, industries and facilities, the following dimensions of sanitary protection zones are established :

enterprises of the first class - 1000 m;

enterprises of the second class - 500 m ;

enterprises of the third class - 300 m;

enterprises of the fourth class - 100 m;

fifth class enterprises - 50 m.

Incinerators and waste processing plants with a capacity of more than 40 thousand tons/year belong to the first class enterprises.

Design of exhaust gas purification system

Design of Sulfur Anhydride Gas Purification System (absorber) The purification process is based on an absorption process in which the oxide reacts with the reagent used (2% of Ca (OH) 2 is most commonly used) to form sulfites. In order to design the apparatus (absorber), it is necessary to specify the efficiency of gas purification. The initial concentration at the border of the sanitary protection zone is 0.0133 mg/m3, the final concentration is 0.003, from where the efficiency is 77.4%. The absorber is represented by a poppet column apparatus with lattice plates. Devices of this type are simple in design, reliable, durable, easy to install. Lattice trays are most commonly used because of their relatively low cost, simplicity of design and reliability. The disadvantage of both the apparatus and the trays is a rather narrow range of loads, that is, the absorber can operate in a narrow range of speeds, a deviation of more than 25% from optimal values ​ ​ threatens to "choke" the column and switch it to a non-operational state. 2% of Ca (OH) 2 is used as a reagent (as a proven and reliable option). The temperature of the gas entering the absorber is 250 ° C. Gas flow rate - 30 m3/s. The set was calculated using the MathCad program. Program text and results of process, hydraulic and mass exchange calculations are given in Appendix 1, 2, 3. Based on the results of the calculation, phase diagrams of the absorption process are constructed in the apparatus presented in Appendix 4, 5.

List of literature

http://www.recyclers.ru

Methodological guidelines for the calculation of emissions of pollutants into the atmosphere from incinerators and incinerators. Department of Scientific and Technical Information of AKH, Moscow, 1989.

Procedure for calculation of concentrations in atmospheric air of harmful substances contained in emissions of enterprises. OND86. Goskomhydromet. Hydrometeoisdate. Leningrad, 1987

A collection of methods for calculating emissions into the atmosphere of pollutants by various industries. - L.: Hydrometeoisdat, 1986. - 150 s.

Methods for determining gross emissions of harmful substances into the atmosphere. MG347001083: ACT Soyuztekhenergo. - M., 1984. - 35 sec.

SanPiN 2.2.1 ./2.1.1.120003. Design, construction, reconstruction and operation of enterprises, planning and development of populated areas .

GN 2.1.6.1338-03. Maximum permissible concentrations (MPC) of pollutants in the atmospheric air of populated areas.

RD 52.04.18689. Guidance on air pollution control. Moscow, 1991.

GOST 17.2.3.0278. Atmosphere. Rules for establishing permissible emissions of harmful substances by industrial enterprises.

http://www.stroygramota.ru/12_m/54.php

Timonin A. S. Basics of design and calculation of chemical-technological and environmental equipment. Directory. Edition 2e, revised and supplemented. Volume 1. - Kaluga: Publishing house N. Bochkareva, 2002. – 852 pages.

Vetoshkin A.G. Processes and dust cleaning devices. Tutorial. - Penza: Publishing House of Penz. Gos. Unta, 2005.

Basis of chemical equipment design and calculation. Lashchinsky A. A., Tolchinsky A. R., L., "Mechanical Engineering." 1970, 752 pp. Table 476. Ill. 418. Bible. 218 names.