PROCESSES: BASICS OF PROCESS DESIGN - Biomass as a Sustainable Energy Source for the Future - page 207

Input-output diagram of process
Preferred technologies
and license(s)

Process boundary
“battery limit”

Co-feed Fuels

Oxygen

Biomass to energy

Heat

carrier

Reference
process

Power
Syngas

PROCESS

Biomass

Auxiliary
chemicals
(solvents, catalyst, etc.)

Wastes: G / L / S

Utility system

Syngas (1)

Co-feed

Fuels
Heat
Power

Subprocess 1

Oxygen

Subprocess 3

Subprocess 2

Syngas (2)

Biomass

FIGURE 7.8 Splitting a process into subprocesses.

3. Reversely, the intermediate product can be imported if the demand of sub-
process 3 exceeds the joint production capacity of subprocesses 1 and 2. In this
example, the syngas going to subprocess 3 is converted into three products:
liquid fuels, power, and heat.

d. Analysis and (e) Evaluation
These are done for each alternative in the same way as for the full process, end-
ing with (f ) Selection and (g) Documentation of the better options for propa-
gation to the next level of design.

7.8 PROCESS DESIGN: FUNCTIONAL BLOCK DIAGRAM

Design at the third level generates a network of processing functions, encapsulated in
process units. The focus here is on which functions are needed and how they interact
in the network for an optimal performance. Targets are derived for the functional