MAERZ

Key factors to minimise emissions from parallel flow regenerative lime kilns

1 Formation of NO_x in an oil fired PFR lime kiln

2 Formation of NO_x in a lignite-fired PFR lime kiln

3 Temperatures at burner lance tips with lignite firing

4 Temperatures at burner lance tips with natural gas firing

5 Burning temperature and reactivity of burnt lime

6 Gas flow in a typical circular Maerz PFR lime kiln

7 Temperature profiles of a circular PFR kiln with natural gas firing

8 Temperature profiles of a circular PFR kiln with lignite firing

9 Different cases with regard to flame length and channel temperature as a result of excess air setting

10 Selective kiln charging for optimal combustion air distribution

All Maerz

3D image of a round PFR lime kiln

All Maerz

Emission reduction is a significant topic in the lime industry. This article concentrates on NO_x formation in PFR lime kilns, as these kilns provide the highest thermal efficiency of all kiln types. It goes on to share with its readers the conclusions drawn from years of research and development by Maerz Ofenbau AG, on how to reduce NOx formation, thereby minimising emissions and contributing to a healthier environment.

1 Introduction

Directive 2010/75/EU of the European Parliament, adopted on November 24^th, 2010, lays down rules for EU member states on the integrated prevention and control of pollution arising from industrial activities. Member states are obliged to take the necessary measures to ensure that no installation, in this case no lime kiln, is operated without a permit. Germany incorporated the IED (Industrial Emissions Directive) 2010/75/EU into national law (BlmSchG) in May 2013. Other EU member states have reached an equivalent status and are currently implementing the IED into their respective...