Reburning of Animal Waste Based Biomass with Coal for NOx Reduction, Part I: Feedlot Biomass (FB) and Coal:FB Blends

Hyukjin Oh,Kalyan Annamalai,Paul G. Goughner,Ben Thien,John M. Sweeten

doi:10.3390/en14238030

Abstract

Cattle biomass (CB or manure from cattle) is proposed as reburn fuel under slightly fuel-rich conditions. The CB includes wastes from cattle feedlots (cattle grown in feedlots to slaughter weights of 450–640 kg) termed as Feedlot Biomass (FB) and cattle wastes from dairy farms termed as Dairy Biomass (DB). NOx emissions from coal-fired power plants can be reduced by using pure CB and Coal:CB mixtures as reburn fuels (10~30% by heat) injected after the primary combustion region. Experiments with Coal:CB mixtures as reburn fuels were performed using the 30 kW burner facility. Part I deals with results from experiments using pure FB and Coal:FB blends as reburn fuels while Part II presents results on extent of NOx reduction using pure DB and Coal:DB blends as reburn fuels (RF). In the current work, results on NOx emission are presented with FB and Coal:FB blends as RF. The parametric studies include: equivalence ratio in reburn zone (ERRBZ), vitiated air, angle of reburn nozzles, presence and absence of heat exchangers (HEXs), and baseline NOx concentration. The optimum operating conditions for FB reburning were found to be conditions with vitiation at ERRBZ = 1.1 with 45° upward counter-current injection in the presence of HEXs. NOx emissions were reduced by as much as 96%.

Highlights

Introduction and Literature ReviewThe current method of disposal of cattle manure is to apply it as fertilizer on the land near cattle feedlots
Biomass (HAFB) and High Ash Dairy Biomass (HADB), and that collected from fly ash paved surfaces containing less ash is termed as Low Ash Feedlot Biomass (LAFB) and Low
The fuel characteristics of natural gas, coal and various reburn fuels are presented first followed by brief description of experimental set up and operational conditions and NOx emission relations in terms of kg/GJ

Summary

Introduction

The current method of disposal of cattle manure (termed as cattle biomass, CB) is to apply it as fertilizer on the land near cattle feedlots (acronyms at end of text). The CB scraped from the soil surface of feedlots containing high ash is termed High Ash Feedlot. Biomass (HAFB) and High Ash Dairy Biomass (HADB), and that collected from fly ash paved surfaces containing less ash is termed as Low Ash Feedlot Biomass (LAFB) and Low. Ash Dairy Biomass (LADB). Biomass samples prior to composting are termed raw manure, and samples taken after about 45 days of composting involving successive wetting and turning cycles are termed partially composted (PC) [1]. Samples taken after about 120 days of composting (which involves wetting and turning cycles) are termed finished compost

Methods

Results

Conclusion