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Chap.7 Material Flow Analysis（Part 1）The Improved Dynamic Model for SFA
Question 2
How to analysis the material flow ?
A dynamic model
The original framework
A STAF model
The improved framework
The improved framework for lead flow analysis
?Take Lead as the objective metal
?Nonrenewable resource depletion, the reserve base can be
used for about 10 years
?Toxic metal: is a poisonous metal that can damage nervous
connections (especially in young children) and cause blood and brain disorders
?The anthropoganic flow rate is about 13 times higher than
the natural flow rate
?Important modern industrial materials
?Wide usage in modern industrial fields: mechanical, electrical, and chemical engineering
?Main usage：60 -70% of refined lead is used in
manufacturing of Lead-acid battery (LAB)
?Position of China in the world: the second biggest
producer and consumer, main lead products exporter, and
lead ore importer
quick increase in production of refined lead and LABs
To obtain some rules, used to lead ore resource conservation and
environmental quality improvement
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2
3
4
5
1990199219941996199820002010Lead Mt
Research object ：LAB system ，in 1999，75%of refined
lead was used in LAB manufacture
?Methodology ——
τ
???=P F The service provided by LABs ：store and transfer electric
energy ,kWh
，Annual transferred electric energy ，kWh/yr
，specific energy,kWh/kt (Pb) lead content in batteries ，kt/yr
the life span of LABs ，average weighted value ，yr
∑=i E E P E F =P τ?τ??=E S
●Environmental impacts definition：
●Eco-efficiency：
resource efficiency：kWh/kt Pb
environmental efficiency:kWh/kt Pb
R
S
r=
Q
S
q=
R
Q
resource load：lead ore consumption，，lead content，kt/yr emission load：lead emissions，，lead content,kt/yr
Methodology——Assumption：
Ignored the time spent in various of production
The average life-span of LABs is , and keeps constant in research period
All LABs become obsolete after years of its production, and return to secondary lead production
τ?
τ?
?Lead flow schematic of product life cycle
?The lead-flow diagram for the LAB life cycle. Stage I is lead mining, concentrating , smelting, and refining. Stage II is battery manufacturing and Stage III is battery use.
、——t he annual production of LABs in year and ，t/yr ——recycling rate, the ratio of the old lead scrap reused in lead production in year τ to the total LAB production △τ years ago, t/t ——moderate recycling rate, the ratio of the lead scrap produced in LAB manufacturing that become inputs for lead production to the total production of batteries in the same year, t/t.——lead emission ratio, the ratio of the lead emissions to the lead content of batteries produced in the same year ，t/t ，
Parameters definition ：
αβγP τP ττ-?ττ-?τ12
γγγ=+
1()Q P P τττγα-?=+-F P τ=???S E τ=??Lead ore consumption load:
Lead emissions:
Service provided:
=1+P -P τττγα-?R （）