1.0 INTRODUCTION

Hydrochloric acidis a clear, colorless, highlypungentsolutionofhydrogen chloride(HCl) in water. It is a highlycorrosive,strongmineral acidwith many industrial uses. Hydrochloric acid is found naturally ingastric acid.It was historically calledacidumsalis,muriatic acid, andspirits of saltbecause it was produced fromrock saltandgreen vitriol(byBasiliusValentinusin the 15th century) and later from the chemically similar substancescommon saltandsulfuric acid(byJohann Rudolph Glauberin the 17th century). Free hydrochloric acid was first formally described in the 16th century byLibavius. Later, it was used by chemists such asGlauber,Priestley, andDavyin their scientific research.During theIndustrial Revolutionin Europe, demand foralkalinesubstances increased. A new industrial processbyNicolas Leblanc(Issoundun, France) enabled cheap large-scale production ofsodium carbonate(soda ash). In thisLeblanc process, common salt is converted to soda ash, using sulfuric acid, limestone, and coal, releasing hydrogen chloride as a by-product. Until the BritishAlkali Act 1863and similar legislation in other countries, the excess HCl was vented to air. After the passage of the act, soda ash producers were obliged to absorb the waste gas in water, producing hydrochloric acid on an industrial scale.For the production, hydrochloric acid is prepared by dissolvinghydrogen chloridein water. Hydrogen chloride can be generated in many ways, and thus several precursors to hydrochloric acid exist. The large-scale production of hydrochloric acid is almost always integrated with the industrial scaleproduction of other chemicals.In industrial market, hydrochloric acid is produced in solutions up to 38% HCl (concentrated grade). Higher concentrations up to just over 40% are chemically possible, but theevaporationrate is then so high that storage and handling need extra precautions, such as pressure and low temperature. Bulk industrial-grade is therefore 30% to 35%, optimized for effective transport and limited product loss by HClvapors. Higher concentrations require the material to be pressurized and cooled to reduce evaporation losses. In the United Kingdom, where it is sold as "Spirits of Salt" for domestic cleaning, the potency is the same as the US industrial grade.Besides, hydrochloric acid is used for a large number of small-scaleapplications, such as leather processing, purification of common salt, household cleaning,andbuildingconstruction.Oil productionmay be stimulated by injecting hydrochloric acid into the rock formation of anoil well, dissolving a portion of the rock, and creating a large-pore structure. Oilwell acidizing is a common process in theNorth Sea oilproduction industry.Hydrochloric acid has been used for dissolving calcium carbonate, i.e. such things as de-scaling kettles and for cleaning mortar off brickwork, but it is a hazardous liquid which must be used with care. When used on brickwork the reaction with the mortar only continues until the acid has all been converted, producingcalcium chloride,carbon dioxide, and water:2HCl + CaCO3 CaCl2+ CO2+ H2OMany chemical reactions involving hydrochloric acid are applied in the production of food, food ingredients, andfood additives. Typical products includeaspartame,fructose,citric acid,lysine,hydrolyzed vegetable proteinas food enhancer, and ingelatinproduction. Food-grade (extra-pure) hydrochloric acid can be applied when needed for the final product.

2.0 Process Flow Diagram

Figure 1: Process Flow Diagram for the manufacturing of Hydrochloric acid

3.0 Process Description

MANUFACTURE HCl is manufactured by various methods as follows 1. Synthesis from hydrogen and chlorine 2. From salt and sulfuric acid 3. As by-product from chemical processes 4. From incineration of waste organics 5. Hydrochloric acid solutions

We choose the method manufacturing of Hydrochloric Acid from salt and Sulphuric AcidReaction

1. NaCl + HSONaHSO4 + HCl 2. NaCl + NaHSO NaSO+ HCl

Salt (NaCl) and sulfuric acid are charged to the furnace. It is desirable to keep one of the components in the reaction mixture in a liquid form in both steps. The first step is carried out at the lower temperature compare to second step. Even so, for liquefaction of NaHSO4, which is required to carry out in second step, material is heated up to 4000C. Sodium sulfate in form of sludge is collected from the bottom of the furnace. The product and unconverted sulfuric acid is sent to further processing in which recovery of sulfuric acid and nitric acid in cooling tower and absorber respectively. Hydrochloric acid gas is cooled absorbed in water or dilute HCl solution by passing through cooler and absorber through the connecting pipe. The strength of acid produced is generally 32-33 %. The heat of absorption of HCl in water is removed by spray of cold water outside the absorber. The solution of HCl flows into a storage tank.4.0 Piping & Instrumentation Diagram

Figure 1 : Process & Instrumentation Diagram of batch reactor

5.0 description instrument involved in processBased on the Process Flow Diagram that has been chosen,the equipments involved in the production of HCl are reactor,cooler,absorber and scrubber.From all of the equipments,we chose reactor for piping and instrumentation Diagram in our project.For the reactor we chose batch reactor. The stirred tank batch reactor is still the most widely used reactor type both in the laboratory and industry. A batch reactor is one in which a feed material is treated as a whole for a fixed period of time. Batch reactors may be preferred for small-scale production of high priced products, particularly if many sequential operations are employed to obtain high product yields. Batch reactors also may be justified when multiple, low volume products are produced in the same equipment or when continuous flow is difficult, as it is with highly viscous or sticky solids-laden liquids. Because residence time can be more uniform in batch reactors, better yields and higher selectivity may be obtained than with continuous reactors. Instruments involve in the reactor as shown in Figure 2 are valves, pumps, flow meter, thermocouple and bourdon tube.

Centrifugal Pump

Figure 3 : PumpApumpis a device that moves fluids (liquidsorgases), or sometimesslurries, by mechanical action. Pumps can be classified into three major groups according to the method they use to move the fluid:direct lift,displacement, andgravitypumps. Pumps operate by some mechanism typicallyreciprocatingorrotary, and consumeenergyto performmechanical workby moving the fluid. Pumps operate via many energy sources, including manual operation, electricity,engines, orwind power. Mechanical pumps serve in a wide range of applications such aspumping water from wells,aquarium filtering,pond filteringandaeration, in thecar industryforwater-coolingandfuel injection, in theenergy industryforpumping oilandnatural gasor for operatingcooling towers. Based on piping and instrumentation diagram of the batch reactor above, there are three pump in this process. The first pump situated from the feed storage to the reactor directly and the second pump situated at outflow of reactor which is between two control valve. Generally there are two types of pump which is Centrifugal Pumps (or Roto-dynamic pumps) and Positive Displacement Pumps.

Figure 4: Centrifugal pumpThecentrifugal or roto-dynamic pumpproduce a head and a flow by increasing the velocity of the liquid through the machine with the help of a rotating vane impeller.Centrifugal pumps include radial, axial and mixed flow units.Centrifugal pumps can further be classified asend suction pumps,in-line pumps,double suction pumps,vertical multistage pumps,horizontal multistage pumps,submersible pumps,self-priming pumps,axial-flow pumps,regenerative pumps. Second pump is Positive Displacement Pumps. Thepositive displacement pumpoperates by alternating of filling a cavity and then displacing a given volume of liquid. The positive displacement pump delivers a constant volume of liquid for each cycle against varying dischargepressure or head.The positive displacement pump can be classified as reciprocating pumps - piston, plunger and diaphragm, power pumps,steam pumps, rotary pumps - gear, lobe, screw, vane, regenerative (peripheral) and progressive cavity.In this process the type of pump that suitable use is centrifugal pump. This is because there is no drive seal so there is no leakage in pump, there are very less frictional losses. There is also can be said have no noise, most efficiency and have minimum wear compare to others. In the centrifugal pump, there is a gap between pump chamber and motor, so there is no heat transfer between them. Then because of the gap between pump chamber and motor, water cannot enter into motor so there is no heat transfer between them.Temperature MeasurementThermocouple

Figure 5: ThermocoupleIn this process thermocouple is used to measure the temperature in the reactor . This is to make sure the temperature is not over limit which is can cause the equipment to be overheating. Athermocoupleis a temperature-measuring device consisting of two dissimilar conductors that contact each other at one or more spots, where a temperature differential is experienced by the different conductors (or semiconductors). It produces avoltagewhen the temperature of one of the spots differs from the reference temperature at other parts of the circuit. Thermocouples are a widely used type oftemperature sensorfor measurement and control,and can also convert a temperaturegradientinto electricity. Commercial thermocouples are inexpensive,interchangeable, are supplied with standard connectors, and can measure a wide range of temperatures. In contrast to most other methods of temperature measurement, thermocouples are self powered and require no external form of excitation. The main limitation with thermocouples is accuracy; system errors of less than one degreeCelsius(C) can be difficult to achieve. Certain combinations of alloys have become popular as industry standards. Selection of the combination is driven by cost, availability, convenience, melting point, chemical properties, stability, and output. Different types are best suited for different applications. They are usually selected on the basis of the temperature range and sensitivity needed. Thermocouples with low sensitivities (B, R, and S types) have correspondingly lower resolutions. Standard thermocouple types are types T, J ,K and E. In this process type K are choose to be used. Type K (chromelalumel) is the most common general purpose thermocouple with a sensitivity of approximately 41V/C (chromel positive relative to alumel when the junction temperature is higher than the reference temperature). Type K thermocouples usually work in most applications as they are nickel based and exhibit good corrosion resistance. It is the most common sensor calibration type providing the widest operating temperature range. Due to its reliability and accuracy the Type K thermocouple is used extensively at temperatures up to 2300F (1260C). This type of thermocouple should be protected with a suitable metal or ceramic protection tube, especially in reducing atmospheres. In oxidizing atmospheres, such as electric furnaces, tube protection is not always necessary when other conditions are suitable; however, it is recommended for cleanliness and general mechanical protection.

Flow measurementFlow meter A flow meter is a device used to measure the flow rate or quantity of a gas or liquid in a pipe. Flow measurement applications are very diverse; consider these examples: water flow through an open channel, hydraulic valve leakage, fuel measurement through a fuel injector, or respiratory flow through a peak expiratory flow meter.Although there are many technologies used to measure flow, the positive displacement flow meter is unique as it is the only one to directly measure the actual volume. All other types infer the flow rate by making some other type of measurement and equating it to the flow rate. Flow meters are referred to by many names, such as flow gauge, flow indicator, liquid meter, etc. dependent on a particular industry; however the function, to measure flow, remains the same.In our P&ID,the flow meter situated before entering the fluid entering the reactor.We use two flow meters for the reactor.The flowmeter can be classified into 4 types which are volumetric, velocity,inferential and mass.This reactor use volumetric type such as positive- displacement meter.It measures volume directly.Positive displacement meters provide high accuracy, 0.1% of actual flow rate in some cases and good repeatability as high as 0.05% of reading. Accuracy is not affected by pulsating flow unless it entrains air or gas in the fluid. PD meters do not require a power supply for their operation and do not require straight upstream and downstream pipe runs for their installation. The process must be clean. Particles greater than 100 microns in size must be removed by filtering. They are most widely used as household water meters. In industrial and petrochemical applications, PD meters are commonly used in for batch charging of both liquids and gases. Velocity is major effect on the accuracy and performance flow meter.

Figure 6: Orifice Plate

The flow measurement device that we choose orifice plate.Two common types of fluid meters are the orifice and venturi meters. They are both differential pressure flow meters. It means that a pressure difference is measured some two points in the pipe. This difference in measure can be related to the velocity of the fluid in the pipe using the Bernoulli equation. These two meters both induce minimum flow area in fluid flow in the pipe. For orifice meter, the minimum cross sectional area is called the vena contracta. For venturi meters, it is called the venturi throat.An orifice meter is simple apparatus consists of a flat plate with a drilled hole inserted into the pipe. This flat plate or commonly known as orifice plate causes restriction in the fluid flow and will create pressure difference before and after the orifice plate. Because of the restriction, the fluid flow will take the form of the restriction and will have a change in cross sectional area depending upon the area of the hole in the restriction. From a half or twice the diameter of the pipe to the orifice plate a minimum cross section of the flow is expected and this is called the vena contracta. Pressure difference is then measured from an arbitrary point before the orifice plate (usually a length equal to the diameter of the pipe) and the vena contracta. This pressure difference can then be related to the velocity of the fluid flow.The orifice plate is very inexpensive for it is just a flat plate and a thin orifice plate. It is also very easy to install in the pipeline. But one disadvantage of this meter is it maximizes form friction. And it is very serious that by using this kind of meter a large percentage of pressure drop is unrecovered. The fluidvelocity is increased at the opening of the orifice plate and not much energy is lost but as it flows through and starts slowing down, much of the excess energy is lost.Unlike the orifice meter, form friction is minimized in the venturi meter. The meter is streamlined shape and almost eliminates boundary-layer separation and thus form drag is assumed negligible. It has a converging and a diverging part. The converging cone must be 25o to 30o. The diverging cone must not exceed 7o. The pressure difference is measured between the upstream side of the cone and the venturi throat. And again, as for all pressure differential flow meters, this pressure difference can be related to the velocity of the fluid flow. A disadvantage of this flow meter is that it is large, difficult and expensive to manufacture. Also, because of its large area, it is difficult to install in our pipeline.

Level measurementSight Glasses

Figure 6: Sight Glasses The level of measurement refers to the relationship among the values that are assigned to the attributes for a variable.The level measurement device that we choose to add is sight glass.It is visual measurement, transparent tube of glass and level inside the vessel shown in the level sight glass. The tube has a scale- indicator for direct reading.Simple sight glasses may be just a plastic or glass tube connected to the bottom of the tank at one end and the top of the tank at the other. The level of liquid in the sight glass will be the same as the level of liquid in the tank.It also can adapt to open and closed tank and use for both low and high pressure process. We chose high pressure sight glass instead of low pressure glass, because it contains liquid under high pressure- reflex sight.It also tolerates higher temperature and pressure.It is installed in protective high pressure housing with I inch thick.

Valves

Figure 8: Ball valve Figure 9: Butterfly ValveValves are any devices for halting or controlling the flow of a liquid, gas, or other material through a passage, pipe, inlet, outlet, etc.We use two types of valves which are butterfly valve and ball valve.The butterfly valve are situated at the entering of the reactor while one ball valve use after the fluid flows out from reactor.A butterfly valve is a flat valve that is either 1 piece or 2 pieces. The name comes from the 2 piece that operates like butterfly wings, when opened they fold inward to allow flow and look like a set of wings touching each other. When closed they are flat. A single piece is a flat disk that rotate about the shaft of the valve. It is still called butterfly as that is what it was made from. A ball valve is just that, a valve that utilizes a ball to control flow. Inside the ball has been bored through to allow flow to pass through it. The hole bored into the ball is equal to the ID of the pipe connecting to it, therefore the valve is much larger than the pipe. Ball valves are the typical norm on most installations, the variety of valves that you can obtain allow for use on multiple services and pressures. Butterfly valves are used when you have limited space for a valve and you are not concerned about flow losses due to the disk being in the flow path. They are also used as control valves to limit flow and induce pressure drops. Butterfly valves typically pick up where ball valves stop, which is size dependent. Ball valves can be used in all sizes, but typically stop at 6"-8" which after that butterfly or gate valves are used as it is more economical.Pressure MeasurementBourden Tubes

Figure 4:Bourden tubesPressure must be considered when designing many chemical processes. Pressure is defined as force per unit area. There are three types of pressure measurements which is first absolute pressure - atomospheric pressure plus gauge pressure. Second, gauge pressure - absolute pressure minus atmospheric pressure and lastly differential pressure - pressure difference between two locations. In order for a pressure controlled system to function properly and cost-effectively, it is important that the pressure sensor used be able to give accurate and precise readings as needed for a long period of time without need for maintenance or replacement while enduring the conditions of the system. Several factors influence the suitability of a particular pressure sensor for a given process: the characteristics of the substances being used or formed during the process, the environmental conditions of the system, the pressure range of the process, and the level of precision and sensitivity required in measurements made.Bourdon tube are choose to measure the pressure inside reactor because of it is the most common type in many areas and are used to measure medium to high pressures. They cover measuring spans from 600 mbar to 4,000 bar. The measuring element is a curved tube with a circular, spiral or coiled shape, commonly called a bourdon tube. This tube moves outward when the pressure inside the tube is higher than the external pressure, and inward when the internal pressure is lower. This motion is proportional to the pressure to be measured, and it is coupled to the pointer mechanism.The types of bourdon tubes are varies in specific use and space accommodations for better linearity and larger sensitivity. In this case, the most suitable is c-type. C -type bourdon tube pressure gauge is works on the principle of Elasticity. It is made of phosphorous bronze,glass baralium or copper. For repeatability, the c-types bourdon tubes materials must have good elastic or spring characteristics. The surrounding in which the process is carried out is also important as corrosive atmosphere or fluid would require a material which is corrosion proof.

6.0 Conclusion & Recommendation

In conclusions, instrumentation plays an integral part in industry. It enables processes to be done in the right conditions such as temperature, pressure and volume. For example, the acid removal column require instruments to measure temperature in and out and measure the pressure. The process of hydrochloric reactions involves instruments such as Acid Removal Column, HCl Removal Column and Water Removal Column. In short, the process of recovery of hydrochloric acid uses acid removal column to condense hydrochloric acid and the acid goes to acid-organic separator and HCl absorber. The absorbed HCl then flow to HCl removal column where the water removed flow from the bottom feed of HCl removal column to Water Removal Column.It is suggested that manufacturer use a more environmental friendly process to recover HCl because this process produce considerable amount of stack emissions containing HCl, particles and chlorine that can cause hazard to environment.

7.0 REFERENCES

1. Robert H. Perry, Perrys chemical engineers handbook,McGraw-Hill 7th edition.2. Carlos A. Smith, Ph.D., P.E.; Armando B. Corripio, Ph.D., P.E., Principles and Practice of Automatic Process Control, John Wiley & Sons, Inc., 2nded.3. Pawan K. Tech B. (2013) Instrument & Control Engineering. National Institute of Technology. Jalandhar4. William. D, Fundamental of Industrial Instrumentation and Process Control, McGraw Hill Professional, April 21, 20055. John, W. (2014, October 18). Bourdon Tube. Retrieved May 9, 2015, from http://www.instrumentationtoday.com/about-us/6. Marangoni, R. (2013, October 12). Pressure Measurement. Retrieved May 6, 2015, from http://en.wikipedia.org/wiki/Pressure_measurement

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