Title:
The Ignitability (Explosion Group Classification) of Various Producer Gas Compositions
Author(s):
Mellitzer, D., Huber, M.B., Krueger, J., Scheffler, J., Brandes, E.
Document(s):
Paper
Abstract:
Biomass gasification represents one of the most promising and effective methods to cover future energy demands. However the construction and the operation of a biomass gasification plant often involves difficulties. On the one hand the feed should have a stable and uniform composition to assure a certain quality of the producer gas. On the other hand there are explosion protection requirements because explosive gas/air mixtures may occur. Design features based on explosion protection requirements are expensive and are prone to create problems during operation. E.g. the small gaps of a flame arrester may to be blocked partly or completely. Moreover additional maintenance and downtime could appear. The explosion protection measures used are based among others on the so called Maximum Experimental Safe Gap (MESG). Flammable gases and vapours (producer gases) as well as explosion protected equipment are classified into the explosion groups IIA, IIB, IIC based on MESG values (group I is for mining). The MESG is determined according to the standard IEC 60079-20-1. The MESG of most of the pure flammable gases is well known. Because of the wide range of the producer gas composition the determination of each single MESG is not possible. Therefore, it is good practice to base the safety requirements of current wood gas plants on the compound having the lowest MESG. Doing so the influence of the inert gas amounts is ignored entirely. Thus some wood gas plants are likely to be designed too conservative resulting in flame arrester equipment that causes additional difficulties during operation. Based on an estimation method [formula 2] by PTB [1] further investigations have been done. This current estimation method has been extended to take into account the inert gases amounts. As a result of comparative studies of estimated MESG and measured MESG it has been verified that the classification of some existing producer gases is definitely too strict. Furthermore, depending on the oxidant used during the gasification process, even wood gas classified as IIA seems to be possible.
Keywords:
gasification, wood gas, maximum experimental safe gap, MESG, inert gases
Topic:
Thermochemical conversion - Gasification for power and CHP and polygeneration
Subtopic:
Gasification for power and CHP and polygeneration
Event:
18th European Biomass Conference and Exhibition
Session:
VP2.1.18
Pages:
673 - 677
ISBN-13:
978-88-89407-56-1
ISBN-10:
88-89407-56-5
Paper DOI:
10.5071/18thEUBCE2010-VP2.1.18
Price:
FREE
