Figure $1$ shows a simplified process and instrumentation diagram $($PI&D$)$ for a single unit of

a fixed bed reactor for a catalytic steam reforming process. The reactor is designed to produce

hydrogen from an acetic acid$/$steam reforming at the atmospheric pressure. Acetic acid

solution $($acid$/$water$)$ is fed by a pump, Pl which has an automatic control system. Nitrogen

functions as a carrier gas to support the fluid flow rate. The nitrogen flow is controlled by a

mass flow controller, MFC $($control valve$).$ The electrical furnace, $Fl$ and pre$-$heater, $PHl$ are

connected to a controller, $Cl.$ The reaction is endothermic and it takes place after the acetic

acid solution is vaporized inside the reactor with the presence of nickel$/$cobalt catalyst. The

resulted products are channeled to a gas$-$liquid separator through a flanged piping system.

Figure $1$: Schematic diagram of a fixed bed reactor with the feeding system

$($a$)$ Develop a HAZOP study for the reactor vessel based on the following requirements

listed in Table $1$ below.

$($b$)$ List down all the actions required as per the HAZOP study in $($a$).$

$($c$)$ Construct a new piping and instrumentation diagram $($PID$)$ of the system after

implementing the actions required listed in $($b$).$

$($d$)$ Recommend two approaches which fall under the category of intensification and

attenuation $($one approach for each$)$ for making the system shown in Figure $1$

inherently safer. Brief explanation on how the proposed approach can make the

system safer should be given.