Biomedical Engineering Reference
In-Depth Information
are compared with industrialized countries. Therefore, in China, the water crisis
is severe, and water saving and pollution remediation are urgent.
The tasks of water system integration include analysis, synthesis, and transfor-
mation. The targets of analysis are the minimum amount of freshwater and the
minimum wastewater. The target of water system integration is to design a water
network through water reuse, regeneration, and circulation. The water system is
transformed by changing the existing water network, reaching maximum water
reuse and minimum wastewater.
The water system integration method generally includes the water pinch opti-
mization techniques and mathematical programming optimization techniques [
162
].
(1) Water pinch point optimization technique
Pinch technology originated in the 1970s and had new breakthroughs in the 1990s. It
is no longer limited to the thermodynamic problem and more widely extends to the
design of a water system to solve a water crisis. The water pinch point technique is
an important method for industrial water reuse, minimum amount of wastewater, and
wastewater treatment system design. In foreign countries, it has been successfully
applied to some of the refining and chemical enterprises, and the saving rate is up to
20-30 %.
Generally, if the wastewater from a water unit could meet the import require-
ments of another unit in impurity concentration and corrosivity, it can be used to
achieve the purpose of saving freshwater. This wastewater reuse is the main focus
of water conservation.
(2) Mathematical programming optimization technique
The mathematical programming method according to the superstructure uses
computer-aided design to solve water system integration quickly and reliably, and it
is another water network design.
11.4.4
Research Methods for Cellulose Biotransformation
Ecological Industrial Chain
Throughout the cellulose resource development status, there are some issues in
the existing cellulose industry, such as the use of a single component, single
conversion technologies, and low availability of raw materials, which result in great
waste of resources and transformation process pollution. Because of the relative
independence of each operating unit, the process characteristics and the influence
on each other are rarely taken into account, resulting in the isolation of various
technical aspects and lack of coordination and complementarity. It also leads to
additional energy consumption, which is not conducive for improving work and
economic efficiency and potentially increases the cost of production [
141
].
Taking into account characteristics of cellulose, to achieve product diversifi-
cation and comprehensive utilization of lignocellulosic resources, it is necessary
