Problem 4. A process that is being considered for construction has been through several technical reviews; block flow, process flow, and piping and instrumentation diagrams are available for the process. Explain the changes that would have to be made to the three principal diagrams if during a final preconstruction review, the following changes were made: a. The efficiency of a fired heater had been specified incorrectly as 92% instead of 82%. b. A waste process stream flowrate (sent to a sludge pond) was calculated incorrectly and is now 30% greater than before. c. It has been decided to add a second (backup) drive for an existing compressor. d. The locations of several control valves have changed to allow for better operator access