Process Engineering

1.     Introduction of Process Engineering

1.1 Function of Process Engineering

- Transfer the laboratory and pilot plant process information

to fulfill the requirement of process plant mechanical design and instrument and control design

- Major activities include the material and energy balance, sizing of piping and equipment, setting up the requirement of instrument and equipment operation condition such as temperature and pressure.

- Guideline for the plant operation.

1.2 Basic Requirement of a Process Plant

Now, process engineers are always required to proceed the

design in the consideration of the following requirement:

-Safety

-Operability

-Maintenance requirement

-Minimum environmental impact

-Energy efficiency

-Economy

1.3 Process engineers’ role

- Collect process information including licensor list, rule of thumb plant investment cost, pros and cons of each process to assist the project and sales groups in the pursuit of business.

- Provide technical consultancy to the client or project for plant operation trouble shooting.

- Assist or be in charge of the plant start-up and performance test.

- Be capable to do the most of refinery and some petrochemical process plants Front End Engineering Design (FEED)

2. Major Activities of Process Engineering

Basically the process engineering activities are classified into

different areas as listed:

- Feasibility study

- Process design

- System design

- Utility system design

- Plant start up assistance

3. Design Procedure

3.1 Design Work Flow

If the client has already purchased a commercial process license, in most case, the licensor will perform the process design and supplies a PDP (Process design package). In the PDP, at least the PFD, material and energy balance, critical equipment data sheet, and operation procedure should be provided. The process engineers will follow the client specification to complete the process design including the issue or modification of P&ID and other design such as the preparation of equipment data sheets, hydraulic checks, line sizing/list, instrument process data sheets, operation manual, and others.

3.2 Content of Process Design Package

Typical process design package(PDP) will include the following data:

- Introduction

- Design basis

- Process description

- Material and energy balance

- Chemical and utility consumption

- Piping and material specification

- PFD

- P&ID

- Equipment list

- Equipment process data sheet/specification

- Instrument process data sheet/specification

- Reference plot plant

- Effluent data

- Operation procedure

- Key control philosophy in some PDP

4. Feasibility Study

4.1 Major Scope of Feasibility Study

Feasibility study is the first step in the evaluation of the plant investment. It will provide the technical and economical information to assist in the decision making of the investment including some or all of license selection, plant scale, plant site selection, and others. For some of the activities such as market survey and others, process engineers may need

assistance from outside source or other discipline to complete the study.

- Market survey

- Process survey

- Plant site selection

- Capital investment cost estimation

- Operation cost estimation

- Economic analysis

- Sensitivity analysis

4.2 Data Required for Feasibility Study

- Market information such as raw material, product, catalyst, and chemical availability, cost, growth rate…

- Process data such as equipment list and data sheet

- Plant site data such as climate, transportation, and other

infrastructure availability and cost

- Utility including fuel, electricity, water, and other utility

availability and cost

- Labor cost

- Local code and regulation

- Tax information

5. Design Basis

The design basis should include at least the following information:

a. Site conditions (site elevation, temperature, humidity and etc.)

b. Battery limit condition (Temperature /pressure of the process and utility fluid.)

c. Code and regulation in:

- Safety

- Environmental protection

- Specific equipment codes and standard such as boiler, pressure vessel, heat exchanger, pumps and etc.

d. Project specific requirement such as

- Spare philosophy

- Over design and turn down requirement

- Equipment, piping and instrument specific requirement such as type, design conditions, and etc.

6. Process Engineering Design

6.1 Process Design

a. Process simulation

b. Material and energizing balance

c. PFD

d. Equipment sizing

- Static equipment: Fired heater, heat exchanger, tower, drum, silo, tank, filter….

- Rotary machine: pump, compressor, steam turbine, fan/blower,

conveyor, and agitator….

- Package equipment: Desalter, chilling water system…

e. Equipment list

6.2 System Design

a. P&ID

b. Utility flow diagram(UFD)

c. Instrument and control process data

d. Line sizing

f. System hydraulic calculation /check

g. Safety relief system

h. HAZOP study

i. Operation manual

6.3 Offsite/Utility System Requirement

6.3.1 Tankage

a. Raw material

b. Final product

c. Intermediate product

d. Off spec. product

e. Utilities

f. Wastewater or other effluent

6.3.2 Utility System

a. Steam/condensate: HP, MP, LP…

b. Water System: raw water, potable water, cooling water, BFW, Demineralized water, process water, fire water

c. Air: Plant air, instrument air

d. Fuel: Fuel oil, fuel gas

e. Gas: N2

f. Electricity

7. Assistance in plant starting

7.1 Typical process plant start up procedures

a. Precommissioning activities

- Piping cleaning: water flushing, air blowing, steam

blowing, or chemical cleaning

- Tightness test and/or vacuum test

- Refractory and system dry out

- Air removal

- Instrument calibration

- Instrument function test

- Electrical facilities test such as motor no load running test

- Catalyst/packing loading

b. Equipment test run

c. System test run

d. Other procedure prior to feed-in such as catalyst conditioning or oil circulation

e. Feed-in

f. Performance test