Discussion

Block flow diagram is a common diagram that use as a schematic illustration of the major process. It is a simplest flowsheet.Process engineers begins process design with a block flow diagram in which only the feed and product streams are identified.The processes described in the Block Flow Diagram are then broken down into basic functional elements such as reaction and separation sections.There are also identify the recycle streams and additional unit operations to achieve the desired operating conditions.The block or rectangles used represent a unit operation. The blocks are connected by straight lines which represent the process flow streams which flow between the units. These process flow streams may be mixtures of liquids, gases and solids flowing in pipes or ducts, or solids being carried on a conveyor belt.

In order to prepare clear, easy to understand block flow diagram a number of rules should be followed:

unit operations such as mixers, separators, reactors, distillation columns and heat exchangers are usually denoted by a simple block or rectangle.

groups of unit operations may be noted by a single block or rectangle. process flow streams flowing into and out of the blocks are represented by neatly

drawn straight lines. These lines should either be horizontal or vertical. the direction of flow of each of the process flow streams must be clearly indicated by

arrows. flow streams should be numbered sequentially in a logical order. unit operations (i.e., blocks) should be labeled. where possible the diagram should be arranged so that the process material flows from

left to right, with upstream units on the left and downstream units on the right.

Palm oil

Water Acid treated+palm oil Glucose+Na2SO4

H2SO4

Some simple example of Block Flow Diagram of Production of biofuel liquid ABE from palm oil process

Hydrolysis Neutralization

Based on our Block Flow Diagram, there are 14 units operation that involve in ABE biofuel liquid production process. They are hydrolysis,neutralization,2 filtration, sterilization,fermentation,storage,stripping,condensation,3 distillation,mixer and decanting. This BFD indicates the process flow of production biofuel liquid ABE from palm oil.

A Process Flow Diagram shows the relationships between the major components in the system. PFD also tabulate process design values for the components in different operating modes, typical minimum, normal and maximum. A PFD does not show minor components, piping systems, piping ratings and designations.

A Process Flow Diagram should include:

Process Piping Major equipment symbols, names and identification numbers Control, valves and valves that affect operation of the system Interconnection with other systems Major bypass and recirculation lines System ratings and operational values as minimum, normal and maximum flow,

temperature and pressure Composition of fluids

A Process Flow Diagrams should not include:

pipe class pipe line numbers minor bypass lines isolation and shutoff valves maintenance vents and drains relief and safety valve code class information seismic class information

Some simple example of Process Flow Diagram of Production of biofuel liquid ABE from palm oil process

Process Unit Tagging and Numbering

Process Equipment

- identification letters for the equipment classification.

C-compressor or turbine

E- heat exchanger

H- fired heater

P- pump

R-reactor

T- tower

TK- storage tank

V- vessel

Y-designates an area within the plant

ZZ- are the number designation for each item in an equipment class

A/B-identifies parallel units or backup units not shown on a PFD

Example of Process Unit Tagging and Numbering in PFD of Production of biofuel liquid ABE from palm oil process

Based on the Process Flow Diagram of production of biofuel liquid ABE from palm oil process, we can see that there are a few of major equipment that involved in this process. They are:

Hydrolysis tank Neutralization tank Fermenter Ammonium tank Inoculum tank Storage tank Product tank Stripper Distillation column Decanter Heat sterilizer Heat exchanger Condenser Rotary vacuum filter

All these major equipments are very important to make this process successful. Each of these equipment play their own roles.

A Piping and Instrumentation Diagram (P&ID) is a schematic illustration of functional relationship of piping, instrumentation and system equipment components. Beside that, P&ID

shows all of piping including the physical sequences of branches, reducers, valves, equipment, instrumentation and control interlocks. The P&ID are used to operate the process system.

A P&ID should include:

Instrumentation and designations Mechanical equipment with names and numbers All valves and their identifications Process piping,sizes and identification Miscellaneous-vents, drains, special fittings, sampling lines, reducers, increasers and

swagers Permanent start-up and flush lines Flow directions Interconnections references Control inputs and output, interlocks Interfaces for class changes Seismic category Quality level Annunciation inputs Computer control system input Vendors and contractors interfaces Identification of components and subsystems delivered by others Intended physical sequences of the equipment Equipment rating or capacity

A P&ID should not include:

Instrument root valves Control relays Manual switches Primary instrument tubing and valves Pressure temperature and flow data Elbow, tees and similar standard fittings Extensive explanatory notes

In Process and Instrumentation Diagram, process control loop is one of the component. There are components of Process Control Loop: Measuring device (Sensor and transmitter), controller, I/P Transducer( if FCE is control valve) and Final Control Element. ( Control Valve, Pump, Heater)

A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of

a great number of other environmental phenomenon. The output is generally a signal that is converted to human-readable displays at the sensor location or transmitted electronically over a network for reading or further processing.

Temperature Sensor

Flow Sensor

A transmitter is an electronic device that generates and amplifies a carrier wave, modulates it with a meaningful signal derived from speech or other sources, and radiates the resulting signal from an antenna.

Pressure Transmitter

A controller is a device which monitors and affects the operational conditions of a given dynamical system. Furthermore, the operational conditions are typically referred to as output variables of yhe system which can be affected by adjusting certain input variables.

I/P Transducer is a device that converts electric signal to pneumatic signal.

Final Control Element is a device that directly controls the value of manipulated variable of control loop.

Control valve Pump

The table below show the sensor, transmitter and controller that involve in production of biofuel liquid ABE from palm oil process.

Control system at hydrolysis tank Flow Transmitter, Flow Indicating Controller, Flow Fraction

Control system at neutralization tank pHsensor, pH Indicating ControllerControl system at rotary vacuum filter

Flow Transmitter, Flow Indicating Controller

Control system at heat sterilizer Temperature sensor, Temperature Indicating Controller

Control system at fermenter Level sensor, Level Indicating Controller, Flow Transmitter, Flow Indicating Controller,pH sensor,pH Indicating controller, Temperature sensor, Temperature Indicating Controller

Control system at storage tank Level sensor, Level Indicating controllerControl system at stripper Flow Transmitter, Flow Indicating Controller,

Temperature sensor, Temperature Indicating Controller, Level sensor, Level Indicating Controller

Control system at condenser Temperature sensor, Temperature Indicating Controller

Control system at distillation column Temperature sensor, Temperature Indicating Controller, Level sensor, Level Indicating Controller

Control system at mixer Flow Transmitter, Flow Indicating ControllerControl system at decanter Flow Transmitter, Flow Indicating Controller

Types of control loop

Feedback Control Feedforward Control Ratio Control Cascade Control Split Range Control

Feedback Control- measure a process variable and sends the measurement to a controller for comparison to set point. If the process variable is not at set point, control action is taken to return the process variable to set point.

Feedforward Control- to measure important disturbance variable and take corrective action before they upset the process.

Ratio Control- is used to ensure that two or more flows are kept at the same time ratio even if the flows are changing.

Cascade Control- uses the output of the promary controller(master) to manipulate the set point of the secondary controller(slave) as if it were the final control element.

Split Range Control- output of a controller is split to two or more control valves.

Table below shows the types of control loop that involve in the process of making biofuel liquid ABE from palm oil.

Types of process Types of control loopHydrolysis Ratio Control LoopNeutralization Feedback Control LoopFiltration Feedforward Control LoopSterilization Feedback Control LoopFermentation Cascade- Ratio Control Loop, Split Range

Control Loop, Feedback Control LoopFiltration Feedforward Control Loop, Feedback Control

LoopStorage Feedback Control LoopStripping Feedback Control Loop, Split Range Control

LoopCondensation Feedback Control LoopDistillation Feedback Control Loop, Split Range Control

LoopMixing Ratio Control Loop

Valves

Valve is mechanical devices specifically designed to direct, start, stop, mix or regulate the flow, pressure or temperature of a process fluid. It can be manufactured from various materials, mostly made from steel, iron, plastic, brass, bronze and special alloys. Valves can be classified according to function, application and motion.

Types of valves that involve in this process plant are ball valve, diaphragm valve and pressure relief valve.

Ball valve

A ball valve is a valve with a spherical disc, the part of the valve which controls the flow through it. The sphere has a hole, or port, through the middle so that when the port is in line with both ends of the valve, flow will occur. When the valve is closed, the hole is perpendicular to the ends of the valve, and flow is blocked. Example, in this process plant, this valve control the flow of butanol and acetic acid. Ball valve is not suitable for high pressure flow.In this part, flowrate of butanol and acetic acid are lower. So, it is suitable for ball valve to control the flow of the fluids.

Diaphragm Valve

Diaphragm valves (or membrane valves) consists of a valve body with two or more ports, a diaphragm, and a "weir or saddle" or seat upon which the diaphragm closes the valve. The valve is constructed from either plastic or metal. . Their application is generally as shut-off valves in process systems within the industrial, food and beverage, pharmaceutical and biotech industries.

Pressure Relief Valve

Pressure Relief Valve is a  type of valve used to control or limit the pressure in a system or vessel which can build up by a process upset, instrument or equipment failure, or fire.

Control System

Control system at hydrolysis tank

This process is performed to control the flowrate of inlet stream (palm oil, water, and H2SO4) to the hydrolysis tank. The additional equipment that need to install are flow transmitter, flow indicating control and flow fraction. Flow transmitter will detect the changes in flowrate and send signal to flow indicating control. Flow fraction and flow indicating control will control the ratio of the streams which respective to the palm oil stream. The solution become acid treated palm oil.

Control system at neutralization tank

The acid treated palm oil undergo neutralization in neutralization tank. In this process, the flowrate of NaOH is the manipulated variable. pH sensor will detect the changes in pH and send signal to pH indicating control. pH indicating control will control the dosing pump to dose the NaOH to the tank.

Control system at rotary vacuum filter

The solution then filtered in rotary vacuum filter by use of water. Flow transmitter will detect the changes in flowrate of the wash water and send signal to flow indicating control. Flow indicating control will alter the control valve either open or close to control the flowrate of the wash water enter rotary vacuum filter.

Control system at heat sterilizer

In this process, the temperature of heat sterilizer is controlled by using steam. Temperature sensor will detect the temperature in the heat sterilizer and send signal to the temperature indicating control. Temperature indicating control will adjust on the control valve either open or close to maintain the temperature required.

Control system at fermenter

The solution of glucose, ammonium and biomass stream will flow into the fermenter and the flowrate of this inlet stream have been controlled. Flowrate control was secondary control while level control was primary control. Level sensor will detect the level in the fermenter and transmit signal to level indicating control. Flow transmitter will detect the flowrate of each inlet stream. The flow indicating control was used to maintain the ratio of flowrate required. The flow rate will influences the level in the fermenter.

The pH of the solution in the fermenter also will be maintained to pH 6. Dosage of acid and base will be controlled by manipulating it dosing. pH sensor will detect the changes pH in the fermenter and send signal to the pH indicating control. pH indicating control will alter the dosage pump dosing correct amount of acid or base into the fermenter.

The temperature in the fermenter must be maintained to 37° c. The temperature of the fermenter will maintained by manipulated the flow of water inlet to the cooling coil. Temperature sensor will detect the temperature in the fermenter and send signal to the temperature indicating controller. Temperature indicating controller will adjust on the control valve either open or close.

Control system at rotary vacuum filter

In rotary vacuum filter, the flow rate of wash water was manipulated. Flow transmitter will detect the changes in flowrate of the wash water and send signal to flow indicating controller. Flow indicating controller will alter the control valve either open or close to control the flowrate of the wash water enter rotary vacuum filter. The flowrate of inlet also have been controlled by manipulated the pump. Flow transmitter will detect the changes in the flowrate of the wash water and send signal to flow indicating controller. Flow indicating controller will alter the pump speed either slow or fast to control the inlet flowrate to the rotary vacuum filter.

Control system at storage tank

The objective of this process is to control the level of storage tank by manipulated the inlet flowrate to the storage tank. Level sensor will detect any changes of the level in the tank and send signal to level indicating controller. Level indicating controller will alter the control valve either open or close to control the level in fermenter.

Control system of stripper

Then, the solution move into the stripper. In this control system, flow of nitrogen inlet was controlled by manipulated the air compressor. Flow sensor will detect the changes in flowrate of the wash water and send signal to Flow indicating controller. Flow indicator controller will alter the compressor speed either slow or fast to control the air flow to the stripper. The temperature in the stripper was controlled by manipulated the flow of steam to the stripper. Temperature sensor will detect the temperature in the fermenter and send signal to the Temperature indicating controller will adjust on the control valve either open or close. The level in the stripper was contolled by manipulated the flowrate of outlet stream from the stream. Level sensor will detect the level changesw in the stripper and send signal to Level indicating will alter the control valve eiyher open v-111 and close v-112 or vice versa.

Control system at condenser

The solution of inlet stream was condensed by manipulated the flow of cold water to the condenser. Temperature sensor will detect the temperature in the fermenter and send signal to the temperature indicating controller. Temperature indicating controller will adjust on the control valve either open or close.

Control system at distillation column

Temperature of the distillation column was controlled by manipulated the flow of steam to the distillation column. Temperature sensor will detect the temperature in the distillation column and send signal to the temperature indicating controller. Temperature indicating controller will adjust on the control valve either open or close. The level of the fluid in the distillation column have been controlled by manipulated the outlet stream of the distillation column. Level sensor will detect any changes of level in the distillation column and send signal to Level indicating controller. Level indicating controller will open V-2 when level high or open V-1 when level low to achieve required level. This distillation process occur 3 times and acetone and ethanol produce respectively.

Control system at mixer

Lastly, the solution(Butanol + acetic acid) flow into the mixer. Flow sensor will detect any changes of flowrate and send signal to Flow indicating controller. A nother flow sensor will detect changes on flowrate also and send signal to flow fraction and signal also send to flow indicating controller. Flow indicating controller will analyze the signal to give ratio on the two inlet flowrate and alter the control valve either close or open.

Control system at decanter

At decanter, the flow sensor detect the flow of inlet stream and send signal to flow indicating control. The flow indicating controller control the control valve either open or close. At this process, butanol is produce and acetic acid yields as byproduct.