An evaluation of alternatives to energy recovery from municipal solid waste part 1: waste flow and energy potential

ABSTRACT

This two-part paper, which consists of Part 1: waste flow and energy potential, and Part 2: energy balance and carbon footprint, respectively, aims to evaluate alternatives to energy recovery from Municipal Solid Waste (MSW) in Pyongyang. This first part focuses on an evaluation of alternatives to energy recovery from MSW in terms of waste flow and energy potential analysis. This paper proposes three alternatives to energy recovery from MSW, and conducts an evaluation of energy potential for the alternatives, based on an analysis of the existing MSW management options (i.e., recycling & reuse, incineration, landfill, and composting) in the municipality, inclusive of MSW composition and characteristics of waste flow (i.e., refuse-derived fuel) being fed to energy recovery. The results show that alternative 3 (i.e., gasification reactor) could produce the largest electricity, followed by alternative 1 (i.e., grate combustor and fixed dome reactor) and alternative 2 (i.e., fluidized bed combustor). In the meanwhile, alternative 1 accounts for 29.9% of the largest gross efficiency, followed by alternative 3 and alternative 2, as 29.7% and 28.0%, respectively. This study can provide a possibility of energy recovery from MSW to the local planners in Pyongyang.

KEYWORDS:

• Alternatives
• carbon emissions
• energy potential
• energy recovery
• refuse derived fuel

Nomenclature

Latin symbols

Eel	=	electricity from grate combustor or fluidized bed combustor (kWh)
${\text{'}\mathrm{E}}_{\mathrm{el}}$	=	electricity from biogas/syngas (kWh)
$\mathrm{E}{\mathrm{l}}_{\mathrm{per}}$	=	electricity per Nm3 of biogas/syngas (kWh/Nm3)
$\mathrm{LH}{\mathrm{V}}_{\mathrm{feedstock}}$	=	Lower Heating Value of feedstock into gasification reactor or fixed dome reactor (MJ/kg)
LHVgas	=	total Lower Heating Value of the produced syngas or biogas (MJ)
LHVI	=	Lower Heating Value of input materials to each process (MJ/kg)
LHVO	=	Lower Heating Value of output materials from each process (MJ/kg)
LHVper	=	Lower Heating Value per Nm3 of syngas/biogas (MJ/Nm3)
LHVRDF	=	Lower Heating Value of RDF into grate combustor or fluidized bed combustor (MJ/kg)
${\mathrm{m}}_{\mathrm{feedstock}}$	=	weight of the feedstock into gasification reactor or fixed dome reactor (Mg)
mgas	=	volume of the produced syngas/biogas(Nm3)
mper	=	volume of syngas/biogas produced per kg of organic Dry Matter(moDM, kg) in feedstock(Nm3/kgoDM)
mRDF	=	weight of RDF into grate combustor or fluidized bed combustor (Mg)
Ri	=	loss ratio of inerts in each process (wt.%)
Rm	=	loss ratio of moisture in each process (wt.%)
Rl	=	loss ratio of mass in each process (wt.%)

Greek symbols

ηg	=	a gross efficiency of grate combustor or fluidized bed combustor to electricity production (%)
${\mathit{\eta }}_{\text{'}\mathrm{g}}$	=	a gross efficiency of gasification reactor or fixed dome reactor to electricity production (%)
μ	=	the factor converting heating value into electricity, 1MJ≈0.277 kWh

Additional information

Funding

This study was supported by the Ministry of Land and Environmental Protection, the Democratic People’s Republic of Korea.