China
Africa
Explore chapters and articles related to this topic
Industrial and Hazardous Waste Incineration
Published in Gaetano Joseph Celenza, Specialized Treatment Systems, 2020
The kiln temperature and oxygen level are major design factors that must be carefully chosen to meet performance requirements through the expected feed range. The kiln temperature is a result of the heat release of the combustible feed and the quench capacity of the exhaust products; and if required, adjusted with supplementary fuel or quench. The selected operating temperature is governed by regulatory mandates, the required destruction efficiency, and refractory limits. Generally, high kiln temperatures allow greater throughput and produce more efficient oxidation conditions but increase slagging, volatile metal release, and entrainment problems.
Soil Remediation
Published in Kathleen Sellers, Fundamentals of Hazardous Waste Site Remediation, 2018
The combustion unit in a rotary kiln incinerator is a refractory-lined cylinder mounted on a slight incline.172 Wastes and auxiliary fuel injected into the high end of the kiln move downward through the combustion zone as the kiln slowly rotates. This rotation creates turbulence, which promotes thorough combustion. The retention time in the kiln can vary from several minutes to an hour or more, but is typically 30 to 60 min.171,172 At the operating temperature of some 1200 to 1800°F, organic materials oxidize to gaseous compounds and ash. The ash is removed from the lower end of the kiln. It may be sprayed with water to cool the hot ash and to control dust. The off-gases contain water vapor, some desorbed contaminants, volatile metals, particulates, and the products of combustion. The off-gases pass through a secondary combustion chamber, then through air pollution control units for particulate and acid gas removal.
Introduction to Ceramic Fabrication Approaches Including Powder Processing
Published in David W. Richerson, William E. Lee, Modern Ceramic Engineering, 2018
David W. Richerson, William E. Lee
A kiln is a high-temperature furnace. A rotary kiln is a furnace cylindrical in cross section that can be rotated during a powder calcining or synthesis operation. The rotation keeps the powder free-flowing and minimizes bonding of adjacent particles. The rotation can also provide continuous mixing to help achieve a homogeneous powder.
A mathematical model of a twin-shaft parallel flow regenerative lime kiln
Published in Mineral Processing and Extractive Metallurgy, 2023
Sujit A. Jagnade, Saurabh K. Nayak, Jose M. Korath, Nurni N. Viswanathan, Prakash B. Abhale
Many researchers have investigated the kinetics of different limestones to improve the energy efficiency, productivity, and the product quality in various types of lime kilns (Borgwardt 1985; Ar and Doğu 2001; Feng and Lombardo 2002). Thus, the design of kilns and their operation has evolved from primitive batch kilns to sophisticated continuous kilns in the last 50 years. Several types of kilns are use used such as annular shaft with recuperator, short rotary kiln with preheater, long rotary kiln without preheater, high-performance shaft, mixed feed type, twin shaft parallel flow regenerative (PFR) kiln, etc. Various industries use these kilns based on the raw material available, product quality required (reactivity and degree of calcination), types of fuel available, and energy consumption. A comparative study has been carried out by Piringer (2017) wherein he compared the advantages of modern shaft kilns with other kilns and explained the functioning principles of each type of kiln.
Thermal imaging as a tool for process modelling: application to a flight rotary kiln
Published in Quantitative InfraRed Thermography Journal, 2020
The rotary kiln is widely used for the thermal treatment of granular materials, including drying, gasification, heating, pyrolysis, sintering, calcination, roasting and cooling, within various industries. Slightly inclined, a hollow cylindrical apparatus rotates around its central axis. The dimensions can reach 230 m long by up to a 7-m inner diameter. The temperature range of these processes extends from 100 to 2000°C, with the kilns capable of being heated either directly (from the inside) or indirectly (from the outside). The carbon footprint of these facilities is to be considered as non-negligible, as is the case encountered in the cement production sector where wall heat losses can account for 61% of the total energy losses [1]. To limit energy consumption from the temperature controller, two technological limitations must be overcome first, namely the rotational motion of the drum and the extensive temperature range encountered in such systems.