Gas Liquid Reactions – An Introduction
Gas-liquid reactions are very common in Chemical Process Industry and contribute to more than 30% of all the chemical commercial reactions. There are several commercially important reactions where the gas phase is pure/explosive/toxic. In all these cases the gas phase is expensive and complete utilization of the solute gas is desired. When gas is introduced into the liquid, it has a certain residence time after which it leaves the liquid phase and is lost to atmosphere. To prevent this, there are often recovery devices attached in series with gas liquid contactors. However, this requires additional cost of installation of recovery devices and operating costs from recovering, pumping and compressing of recovered gas. The problem of retaining gas within the reactor has been achieved in the recently developed novel reactor design (which is patented). It uses the self induction principle for impellers. Energy efficient impeller designs have been developed for gas induction and gas dispersion. It is also efficient for gas-liquid-solid three phase reactions. The solid phase may be a catalyst or undergo a chemical reaction. The solids concentration may vary from 0.005% v/v (in the case of noble metal catalyst ) or 25% v/v (when solids undergo chemicals reaction). It is a proven design and a large number of reactors are in successful Commercial operation with a size range from 500 to 20,000 liters. This Gas Liquid Induction Reactor (Hydrogenator) is manufactured in India by New Multifab Engineers Private Limited and finds application in a variety of industrial applications.
Hydrogenation Reaction – An introduction
Reactions in which hydrogen is simply added to a molecule are clubbed under the category of “Hydrogenation” Reactions. Hydrogenation is synonymous with reduction. Advantages of hydrogenation over conventional reduction reaction:
- Simpler and more useful procedure, with high yield
- Cleaner products
- Large volumes of solvents and/or solutions not required in processing step – particularly useful when process has to be used commercially
- Suitability to scale up – lab scale to commercial production
Catalytic hydrogenation is widely used in laboratory and industrial processes. Principal usage in laboratory is for chemical syntheses and also as a research tool. Industrial applications are varied: a short list of Clients to whom we have supplied Hydrogenators can be seen below. There are various limiting steps for the reaction, however there are some 8 kinetic resistances which have to be overcome for undertaking a hydrogenation reaction with high yield percentage.
Hydrogen side resistances
- Solution of Hydrogen
- Diffusion to Catalyst
- Chemisorption on Catalyst
Fluid side resistances
- Diffusion to Catalyst
- Chemisorption on Catalyst Other resistances
- Surface reaction on Catalyst
- Desorption of Products from Catalyst
- Diffusion of Products from Catalyst to Liquid phase
Of the above resistances, the chemical reaction kinetic resistances can be tackled by proper selection of catalyst and reaction conditions. However, it is often found that the rate of dissolution of hydrogen in the liquid phase is the rate limiting step. This is where the Hydrogenators manufactured by New Multifab Engineers Private Limited score over other similar process vessels. The key feature of these reactors is the efficiency at which gas – liquid mixing occurs. For this purpose, it is important that the unreacted gas from the gas space is drawn back into liquid. This difficult task has been achieved in the recently developed novel reactor design (which is patented). It uses the self induction principle for impellers. Energy efficient impeller designs have been developed for gas induction and gas dispersion. It is also efficient for gas-liquid-solid three phase reactions. The solid phase may be a catalyst or undergo a chemical reaction. The solids concentration may vary from 0.005% v/v ( in the case of noble metal catalyst ) or 25% v/v (when solids undergo chemicals reaction). It is a proven design and a large number of reactors are in successful Commercial operation with a size range from 500 to 20,000 liters.
We have manufactured Hydrogenators in various sizes. Click on the image to expand it:
These are in use in various industries across India.
Some typical applications of Hydrogenators manufactured and commissioned by us are as follows:
|No.||Application||Range of Reactor Volume||Product Category|
|1||Saturation of double bonds. For example, in this case parafins are formed from olefins or saturated fatty acids or saturated oils from the corresponding unsaturated acids and oils.||5 m3 – 20 m3||Fatty acids, Hydrogenation (or hardening) of natural oils|
|2||Nitrile to amine. In this case C = N group is converted in to -CH2 NH2.||0.1 m3 – 8 m3||Soap Intermediates and Specialty chemicals|
|3||Saturation of aromatic ring. The ring of of substituted aromatic compounds are saturated||0.5 m3 – 4 m3||Substituted anthraquiones, speciality chemicals, perfumery chemicals, cyclohoxyl amine|
|4||Hydrogenation of aromatic nitro-compounds such m-dinitrobenzene, o-nitroanilene, p-nitoanilene, o-dinitrobenzene, p-dinitrobenzens, nitrotoluenes, nitroxylenes, nitrochlorobenzenes, nitroanisoles, nitrocumenes, etc.||2 m3 – 12 m3||Dye, pharmaceuticals and agro-chemical intermediates|
|5||Reductive amination and reductive alkylation||1 m3 – 5 m3||Surface active agents, Pharmaceutical intermediates|
Our Engineering Strengths
The company offers process and mechanical design of custom built equipment under one roof. In house quality assurance practices are followed.
Application of Hydrogenation
1. Aliphatic compounds with one or multiple of double/triple bonds
2. Conversion of Aromatic compounds from Nitro to Amino
3. Conversion of Aliphatic & Aromatic compounds from Cyno to Amines
4. Conversion of Aliphatic & Aromatic compounds from Acids to Aldehydes
5. Conversion of Aliphatic & Aromatic compounds from Aldehydes to Alcohols
6. Rind hydrogenation of variety of aromatics
7. Reductive amination
8. Reductive Alkylation
9. Asymmetric hydrogenation
Our Commitments / Responsibility
We offer a single source responsibility from process / product development stage through design, procurement, construction and commissioning of plant. We shall be part of your team during execution of project – conception to commissioning.
Depending on the reaction, our Gas Induction reactor along with process engineering of the hydrogenation system, one or more of the following objectives / goals can be achieved:
- Shorter reaction time
- Higher selectivity
- Higher yield
- Reduced catalyst load
- Reduced catalyst consumption due to more number of recycles
- Higher productivity
Reduced solvent load if solvent is used as reaction media leading to higher productivity per unit volume of reactor.
Hydrogenation with Gas Induction Reactor – Stirred Vessel (Hydrogenator)
The benefits of gas induction reactor are as follows:
- Complete and Vigorous mixing of gas and liquid
- Uniform suspension of catalyst throughout reaction mixture
- Large gas-liquid contact area, typically 200m2 per m3 of operating volume
- Enhanced rate of mass transfer
- Minimal side reactions
- Reduced reaction time
- Higher heat transfer co-efficient
- Better batch to batch repeatability
- Heat transfer area not a constraint – Heat transfer area can be provided by internal coil as well as external heat exchanger
Hydrogenation with Hydrosyphon System
To overcome limitation of accommodating heat transfer area in stirred vessel, the alternate design is providing an external heat exchanger with recirculation pump.
Our in-house developed hydrogenation system design is without recirculation pump based on Hydrosyphon principle. In this design, heat transfer area is provided out side the vessel as vertical shell & tube heat exchanger.
In this design Hydrosyphon can generate volumetric flow rates equivalent to large size pumps used for re-circulation providing advantage of elimination of rotating parts there by eliminating mechanical maintenance as well as hydrogen embrittlement of metal. Additionally, since our design does not require installation of pump, the power consumption of system is reduced. Hence, this is an eco-friendly solution.
Hydrosyphon system can be designed for high turn-down ratio, even by factor of ‘five’.
- Optimization of catalytic gas/liquid reactions
- Development of specific process
- Providing guidance for handling of all types of catalyst used for hydrogenation like noble metals, Pt/C, Pd/C, Rh-Ni etc.
- Providing guidance for reactivation and reuse of spent catalyst
- Providing guidance for regeneration and reuse of spent catalyst
- Feasibility study & site assessment
- Conceptual design
- Process hazard analysis
- Basic & detail engineering
- Process automation
- Project management
- Consulting for handling of by-products
- Process design for Effluent treatment
The above services can be offered as per requirements.
Plant safety is our commitment. We undertake safety analysis during the design stage combining with monitoring of all operational sequences during operations including start-up and shut-down to avoid formation of any explosive mixture giving intrinsically safe plant.
Typical Hydrogenation System
List of Gas Induction Reactors manufactured by New Multifab Engineers Private Limited
SR NO. CLIENT CAPACITY DESIGN PRES. DESIGN TEMP. M.O.C. QTY INSPECTION YEAR SERVICE (Litre) kg / cm2 ° C 1 Emmellen Biotech Pharma Ltd., Mahad, Maharashtra, India 500 10 100 SS316 1 Internal 1996 Hydrogenation (Hydrogenator) 2 Emmellen Biotech Pharma Ltd., Mahad, Maharashtra, India 500 10 100 SS316 1 Internal 1997 Hydrogenation (Hydrogenator) 3 Jayant Oil Mill, Bhandup, Mumbai, India 2200 30 200 SS316 1 Third Party 1998 Hydrogenation (Hydrogenator) 4 Aarti Industries Ltd., Vapi, Gujarat, India 12000 44 200 SA516 Gr. 70 2 Third Party 1998 Amonolysis 5 Emmellen Biotech Pharma. Ltd., Mahad, Maharashtra, India 250 10 100 SS 316 1 Internal 1998 Hydrogenation (Hydrogenator) 6 Catapharma Chem. Pvt. Ltd., Nashik, Maharashtra, India 3000 32.7 to Full Vacuum 150 SS 304 1 Third Party 1999 Hydrogenation (Hydrogenator) 7 Galaxy Laboratories Pvt. Ltd., Aurangabad, Maharashtra, India 1000 35.15 200 SS 316 1 Internal 1999 Hydrogenation (Hydrogenator) 8 Emmellen Biotech Pharma. Ltd. 250 10 100 SS316 1 Internal 1999 Hydrogenation (Hydrogenator) 9 Aarti Industries Ltd., Vapi, Gujarat, India. 3000 37 200 SS 316L 1 Third Party 2000 Hydrogenation (Hydrogenator) 10 Alta Laboratories Ltd. 100 50 200 SS 316 1 Internal 2000 Carboxylation 11 Erie Chem Pvt. Ltd. 100 20 150 SS316 1 Internal 2000 Hydrogenation (Hydrogenator) 12 Aarti Industries Ltd., Jhagadia,Gujarat, India 10000 37 150 SS 316L 1 Third Party 2000 Hydrogenation (Hydrogenator) 13 Erie Chem Pvt. Ltd. 5000 15 150 SS316 1 Third Party 2000 Hydrogenation (Hydrogenator) 14 Aarti Industries Ltd., Jhagadia,Gujarat, India 50 25 200 SS316 1 Internal 2001 Hydrogenation,Pilot Plant 15 Tagros Chemicals (I) Ltd., Chennai, Tamil Nadu, India 2000 10 150 SS316 1 Dalal, Mott McDonald 2002 Hydrogenation (Hydrogenator) 16 Galaxy Laboratories Pvt. Ltd., Aurangabad, Maharashtra, India 2000 25 150 SS 316 1 Internal 2002 Hydrogenation (Hydrogenator) 17 Metropolitan Eximchem Ltd. 200 70 200 SS 316 1 Internal 2002 Hydrogenation (Hydrogenator) 18 Catapharma Chemicals Pvt. Ltd., Nashik, Maharashtra, India 5000 28 200 SS 316L 1 Third Party 2002 Hydrogenation (Hydrogenator) 19 Aryan Pesticides Ltd, Roha, Maharashtra, India (Div. Of Deepak Nitrite Ltd) 3500 12 200 SS 316 2 Internal 2002 Hydrogenation 20 Hindustan Monomers Ltd 300 35 200 SS 316 1 Third Party 2003 Hydrogenation plus Pilot Plant 21 Catapro Technologies 100 80 200 SS 316 1 Third Party 2004 Hydrogenation pilot plant 22 Catapharma Chemicals p. Ltd. 5000 30 200 SS 316 1 Third Party 2004 Hydrogenation 23 MDB Chemicals P. Ltd 5000 30 200 SS 316 1 Third Party 2004 Hydrogenation 24 Aryan Pesticides Ltd 3000 20 150 SS 316 1 Internal/Client 2004 Hydrogenation 25 Ganesh Polychem Ltd 3000 50 150 SS 316 1 Third Party 2004 Hydrogenation/Amination 26 Aarti Industries Ltd 10000 15 150 SS 316 1 Third Party 2004 Hydrogenation 27 Aarti Health Care Ltd., Dombivali, Maharashtra, India 2200 15 200 SS 316 2 Third Party 2004 Hydrogenation 28 Aarti Health Care Ltd., Dombivali, Maharashtra, India 1100 15 200 SS 316 2 Third Party 2004 Hydrogenation 29 Ven Petrochem, Ankleshwar, Gujarat, India 600 25 150 SS 316 1 Internal 2004 Hydrogenation 30 Modepro India Pvt. Ltd., Navi Mumbai, Maharashtra, India 2000 20 150 SS 316 1 Internal 2004 Hydrogenation (Hydrogenator) 31 Bharat Chemicals Ltd., Tarapur, Maharashtra, India 6000 22 150 SS 316 1 Third Party 2005 Hydrogenation 32 Aarti Industries Ltd., Vapi, Gujarat, India 7500 20 150 SS 316 1 Third Party 2006 Hydrogenation 33 Dheeraj Intermediates Ltd., Vapi, Gujarat, India 10000 20 150 SS 316 1 Third Party 2006 Hydrogenation 34 Ganesh Polychem Ltd 8000 50 250 SA 515 Gr.70 1 Third Party 2006 Hydrogenation 35 Aarti Industries Ltd., Tarapur, Maharashtra, India 6000 20 150 SS 316 1 Third Party 2006 Hydrogenation 36 Suven Life Sciences Pvt. Ltd., Hyderabad, Andhra Pradesh, India 5000 35 200 SS 316 1 Internal 2006 Hydrogenation 37 Suven Life Sciences Pvt. Ltd., Hyderabad, Andhra Pradesh, India 1000 35 200 SS 316 1 Internal 2006 Hydrogenation 38 Suven Life Sciences Pvt. Ltd., Hyderabad, Andhra Pradesh, India 3000 35 200 SS 316 1 Internal 2006 Hydrogenation 39 United Phosphorus Ltd., Jhagadia, Gujarat, India 7000 25 150 SS 316 1 Internal 2006 Hydrogenation 40 Indo Amines 2500 10 150 SS 316 1 Internal 2007 Hydrogenation 41 Karnataka Malladi Biotech Ltd., Mahad, Maharashtra, India 1000 15 150 SS 316 2 Internal 2008 Hydrogenation 42 Indo Amines 2000 15 150 SS 316 1 Internal 2008 Hydrogenation 43 Alta Laboratories Ltd. 4500 18 250 SA 515 Gr.70 1 Internal 2008 Carbonation 44 Chemie Organic Inds. 4000 15 150 SS 316 1 Internal 2009 Hydrogenation 45 Galaxy Laboratories Pvt. Ltd. 3000 35 150 SS 316 1 Internal 2009 Hydrogenation (Hydrogenator) 46 Virchow Labs 1200 35 150 SS 316 1 Internal 2009 Hydrogenation (Hydrogenator) 47 Richter Themis Medicare P. Ltd.. 2500 15 150 SS 316 1 Internal 2009 Hydrogenation (Hydrogenator) 48 Alphs Chemicals 30 10 100 SS 316 1 Internal 2010 Pilot Plant 49 Emmellen Biotech Pharma Ltd. (Embio) 1000 10 100 SS 316 1 Internal 2011 Hydrogenation (Hydrogenator) 50 Kusa Chemicals Pvt. Ltd. 5000 10 100 SS 316 1 Internal 2011 Hydrogenation / Ethoxylation 51 Chemie Organic Inds. 14500 24 150 SS 316 1 Internal 2012 Hydrogenation 52 Gujarat Organics Limited 10000 10 250 SS 316 1 Bureau Veritas 2012 Carboxylation