Journal of Scientific & Industrial Research Vol. 60, September 2001 , pp 728-734

Production of Automotive Catalytic Converter based on

Non-noble Metal Catalyst Technology: A Feasible Option

Rajesh B Biniwale*, Moqtik A Bawase, M M Deshmukh, N K Labhsetwar, R Kumar and M Z Hasan

National Environmental Engineering Research Institute, Nehru Marg, Nagpur 440 020

Received:04December 2000;accepted: 02 May 2001

Vehicular emission is the major contributor to the air pollution problem because of the increased vehicle population. A technology is needed to control autoexhaust pollution problem so as to meet the emission standards set up by government legislation and the upcoming more stringent emission norms. The catalytic converter is successfully utilized to control air pollution from vehicular emissions. National Environmental Engineering Research Institute (NEERI) has developed a non-noble metal­based catalytic converter considering the present and future emission standards. These non-noble metal based converters can also be fitted to old, on-road vehicles, which shares major part of total vehicular emissions, and thus a large market is readily available. Financial analysis reveals that the technology is cost-effective and has wide commercial application. �-

Introduction

The use of motor vehicles has tremendously increased due to population growth and increased urbanization and industrialization . Vehicular exhaust emission contributes to more than 60 per cent to the air pollution in Indian urban settlements . The consequence is that we are expe­riencing serious vehicular emission problems: Table I shows the increase in vehicular population I and total emissions from these vehicles.

Government of India has already made legislation for the use of Catalytic Converters in new passenger cars with effect from April 1 995. Since August 1 998, 43 cit­ies are covered under the scope of this legislation2• Other vehicles including two-wheelers would also require con­verter to meet emission norms of the year 2000 AD as shown in Table 2. NEERI has developed a Catalytic Converter technology as a substitute to imported noble­metal based converter technologies' that are designed to meet the special requirements of India and other devel­oping countries.

Demand for Catalytic Converters

The present vehicle population 1 0 India is approximately 40 mi l l ion w ith a ready market for

* Author for correspondence, rajeshbiniwale@yahoo.com

converter application. There is a steady growth in the vehicle popUlation. The market for the catalytic converter is directly proportional to this growth. Apart from this, in future it will be required to retrofit the old vehicles with catalytic converter as the old vehicles running on the road contribute largely to air pollution problem.

Catalytic converter developed by NEERI is suitable even for old, in-use vehicles and hence large market is available for catalytic converter in India.

Materials and Methods

Catalytic Converter Technology

Catalytic converter developed by NEERI consists of a ceramic support having approx imately 400 cpsi(channels per square inch) of channel density in the case of catalytic converter for four-wheeler. The surface area of support has been improved to the desired level by high surface area alumina washcoating process developed in-house4. A non-noble metal, perovskite type of catalyst is used to achieve conversion of pol lutants. Perovskites are one of the most fascinating group of catalytic materials having densely packed cubic lattice of the general formula ABOr So far, several compounds with perovskite type structures have been described for their applications in various fields 5-9 . They crystal lize in the ABO, form only when specific conditions of

,,:

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BINIWALE et at.: PRODUCTION OF AUTOMOTIVE CATALYTIC CONVERTER 729

Table 1 - Automobile population and exhaust emission in India

Year Old vehicles New vehicles

No. in million Emissions TPD No. in million Emissions TPD

1 989 1 8 26000 1 .8 360

1 996 32 43000 2.8 220

*2001 49 63000 4.7 70

* Estimated

Table 2 - Emission norms for petrol driven vehicles

Emission Norms Pollutant Four wheeler Two wheeler (g/km) T/A COP T/A COP

CMVR CO 2.72 3. 1 6 2.00 2.40 2000 norms HC+ NOx 0.97 1 . 1 3 2.00 2.40 (w.e.f. 1 -4-2000) PM EURO I CO 2.72 3. 1 6 2.00 2.40 (w.e.f. 1 -7-92 HC+ NOx 0.97 1 . 1 3 2.00 2.40 in ECE countries) PM 0. 1 4 0. 1 8 EURO I I CO 2.20 2.20 N.A. N.A. (w.e.f. 1 -7-96 HC+ NOx 0.50 0.50 in ECE countries) PM CMVR: Central Motor Vehicle Rules 1 988, Government of India ECE: European Committee of Environment

physico-chemical and crystallographical parameters of the A and B metal ions are fulfilled. The renewed interest in these non-conventional catalytic materials can be justified due to fol lowing reasons.

• A great flexibility in their chemical compositions with the freedom to influence the properties of active 'B' ion .

• High thermal stability which makes them suitable even for closed-couple applications.

• Great degree of possible tailoring in their physical and chemical properties for future requirements, e. g., lean-bum catalyst.

• Poison resistant nature.

However, their practical feasibility in auto-exhaust applications has been lowered mainly due to their low surface area and comparatively low catalytic activity, particularly under cold start conditions.

Alumina Washcoating on Ceramic Substrate

The ceramic substrate used is cordierite honeycomb substrates having 400 c p s i channel density and wall

thickness of ca 0. 1 5 mm. The porosity of these substrates was in the range of 35-40 per cent and specific surface area in the range of 0.6 to I m2/g. Pore size distribution in macroporous range is important for obtrusion of alumina slurry into pores to get maximum washcoat loading with maximum open frontal area for lower pressure drop. The ceramic substrate was, therefore, characterized for BET-SA, porosity, and pore size distribution. Deep-coating is used for application of alumina washcoat on ceramic substrate, subsequently followed by drying and consol idation by heating in furnace. Specific surface area of alumina washcoated substrate depends on the percentage loading of alumina and temperature of calcination which governs the final phase of alumina in consol idated layer. The specific surface area of alumina washcoated substrate was 25-30 m2/g.

Various oxides such as, La20" Ce20" and zr02 have been blended with alumina slurry as thermal stabilizers. The percentage of this stabilizer was varied as 5, 1 0 and 1 5 per cent of the weight of alumina. Rare earth oxide precoat is used to avoid reaction between alumina and perovskite precursor during synthesis.

7 3 0 J SCI IND RES VOL 6 0 SEPTEMBER 200 1

7 1 98 6478 5758 5039 43 1 9 3399 2R79 2 1 59 1 440

720 0 1\.

1 0 8 .85

20 4.44

... 30

2.98

1\ 40

2.25

.A 1\ 50

1 .82

I,. • 60

1 .54

A 70

1 .34 Two Theta [deg] I d - spacing

Figure 1- a typical X-ray diffraction pattern of perovskite composition

Catalyst Coating

The perovskite catalyst was synthesized fol lowing the various routes using following stoichiometries :

Where A I and B I represent substitution on A and B sites, respectively, of ABO, type perovskite structure. Very high homogeneity was

' maintained in the precursor

phase and perovskite phase was obtained between 500 and 700°C. Use of specific anion was also exploited for better synthesis . The perovskite phase was characterized for its chemical composition, surface area, particle size and structure. X-ray diffraction pattern of perovskite is presented in Figure I .

The complete process of Catalytic Converter manufacture is shown in Figure 2. Vehicle specific modifications in the Catalytic Converter have also been incorporated using mass transfer, pressure drop, and thermal gradient modelling to optimize the reactor dimensions. These specific designs ensure minimum pressure drop across the converter, and adequate retrofit mechanism for the existing Indian vehicles.

Salient features of NEERl's Catalytic Converter

Technology

Following are the sal ient features of NEERI ' s Catalytic Converter Technology:

• Low-cost catalyst compositions. • Thermally stable proprietary alumina washcoat

and catalyst. • Conversion efficiencies sufficient to meet the

norms. • Better poison resistance of catalyst. • Suitable reactor design for low pressure drops

and improved performance. • Suitable for OEM and retro-fitment.

Scale-up of Technology

Scale-up is the process or group of activities by which one moves from the calculations, bench/pilot studies, and demonstrations to a successful commercial operating facility II'. Scale-up studies, therefore, are necessary to ensure the relationship of product developed on laboratory scale to a commercial production. A bench plant facility has been set-up at NEERI to scale-up the critical process steps of converter manufacturing. The important objectives of bench plant study are as follows:

• Identification of major scale-up parameters for unit operations assoc iated with the process.

• Preparation of material and energy balance. • Designing of following equipment

•

• Alumina slurry preparation vessel. • Attritor. • Washcoat application unit. • Activation furnace. Develop cri teria for process control and quality assurance.

,

BINIWALE et at.: PRODUCTION OF AUTOMOTIVE CATALYTIC CONVERTER 73 1

ChardCteri7.ation of washcoat'ed

substrate

Cruming of catalyst coated

substrate ;n melaUic shell

lntegration o f Catalytic Converter with exhaust system

Characleriz .... ltioll and laboratory evaluation of coated S\lbSlrale

Designing vehicle specific catalytil: converter

D�"1lamOmeler tes1i11g

Figure 2- Process for catalytic converter manufacturing I The bench p lant fac i l i ty , w ith wel l designed

equipment like slurry preparation vessel, attritor, coating unit, activation furnace, is having capacity to produce 5000 and 20000 units of catalytic converters for four­wheelers and two-wheelers, respectively.

Results and Discussion

Evaluation of Catalytic Converter The catal ytic converter prototypes have been

extensively evaluated for their performance, durabi lity and for other parameters in-house and by third parties as well. Following are the various in-house techniques for evaluation of Catalytic Converter.

• Engine dynamometer evaluation for pressure drop, power loss , mapping , matching and performance, with respect to particular engine in consideration.

• Mass emission trials for EURO I ( Indian 2000 norms) compliance on two-wheelers .

• Durabil ity trials on engine dynamometer. • Field trials for durabil i ty.

The typical oxidative type catalytic converter performs with CO and HC mass conversion efficiencies of 50 to 60 per cent and 80 to 90 per cent, respectively, for four­wheeler veh i c l e s . CO and HC mass convers ion efficiencies for two-wheeler catalytic converters are 65 to 75 per cent and 55 to 65 per cent, respectively. These conversion efficiencies are sufficient for meeting present emission norms. Table3 shows the representative mass emission conversion efficiency results for four-wheeler and two-stroke, two-wheelers.

Durabil ity of converter has also been evaluated following the field trial procedure on in-house, old vehicles. The durabil ity estimated is about 50,000 km, which confirms its suitability for the retrofit mechanism. The mass emission tests have been successfu l ly completed, using the standard test procedures.

Details of Manufacturing Project

The technology, which is offered, should be based on realistic assessment of costs and benefits, keeping in view the technical and economical feasibility. Many of the potential benefits of this technology assure sufficient incentives to the manufacturers to achieve the desired goals. A key component, therefore, must be the cost­effective production of catalytic converters w i th performance to ensure compliance with standards.

Financial Analysis of the Manufacturing Process

The detailed financial analysis is done considering the various cost components involved in the process to arrive at optimum plant capacity, as shown in the Table4. It is observed that as the capacity of the plant (No. of units produced) increases the fixed capital and operating capital both increase but evidently increase in fixed capital is not as proportional as increase in the operating capita\ . With increase in the capacity of the plant the pay back period decreases. Variation in pay back period and project cost is plotted against various plant capacities, as shown in Figure 3. Pay back period reduces with increase in plant capacity. The reduction in pay back period is not very significant after plant capacity of 1 .25 lakh units/yo Considering the reduction in pay back period and total project cost, a plant capacity of 1 .0 lakh units/ y is most suitable .

Preliminary Project Calculations

From the cost estimates, carried out on different plant capacities, it has been observed that capacity of plant of 1 .0 lakh units with 30 per cent of four-wheeler and 70

732

3.00 2 .80 2.60

i 2.40 to " � 2 .20 't> 0 1 2.00 ". u 1 .80 to J:l '" '" ll. 1 .60

1 .40 . 1 .20 1 .00

A) Four wheeler

Pollutants (glkm)

CO HC

NOx

B) Two wheeler Pollutants

(glkm) CO HC

J SCI INO RES VOL 60 SEPTEMBER 2001

5.00 4.50

· 4.00 .. .r; 3.50 :; 0 0 3.00 :; !!.

2.50 8 � Pay back period u

2.00 � ___ Total project cost .� ... 1 .50 :3 0 .... 1 00

0.50 0 .00

0.50 0.75 1 .00 1 .25 1 .50 1 .75 2.00 Capacity of plant (Iakh un its)

Figure 3- Effect of capacity of plant on pay back period

Table 3 - Result of mass emission test on catalytic converter

Without catalytic converter I " III

3.29 2.79 2.98 0.9 1 0.97 0.90 1 .52 1 .5 1 1 .46

With catalytic converter I " III

1 . 1 5 1 . 39 1 .45 0. 1 5 0. 1 3 0. 1 6 1 . 32 1 .25 1 .20

Without catalytic With catalytic converter converter I I I II I

1 .99 0.67 0.59 0.44 2.77 1 . 1 2 1 . 1 2 0.92

Average percentage conversion

55.52 84. 1 7 1 6.03

Average percentage conversion

7 1 .52 6 1 .97

SO

±6.74 ±1 .83 ±2.07

SO

±4.79 ±3.40

NOx Practically zero conc. of NOx is observed with catalytic converter

Table 4- Comparative cost elements for different plant capacities

Cost (in Rs lakhs)

SI. no. Capacity of plant Fixed cost Operating cost Total project cost Pay-back period (y) (No. of units/y )

0.50 1 84.40 644.97 3 1 9.81 2.74

2 0.75 235. 1 9 959.77 339.49 2.09

3 1 .00 279.50 1 297.53 360.24 1 .83

4 1 .25 31 9.54 1 589.36 378.84 1 .63

5 1 .50 356.48 1 904. 1 6 409.85 1 .54

6 1 .75 391 .03 221 8.96 436.06 1 .45

7 2.00 423.64 2533.75 462.92 1 .42

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BINIWALE et af.: PRODUCfION OF AUTOMOTIVE CATALYTIC CONVERTER 733

Table 5- Basis for project calculations

Total capacity of production

For four-wheeler 30 per cent of total production

1 00000 units

30000 Units

70000 Units

300

For two-wheeler 70 per cent of total production

Number of working d1y Number of shifts/d

per cent of two-wheeler Catalytic Converters production break-up is suitable with respect to demand and economic criteria. A total of 300 working days in a year with three shifts per day were considered for calculation of equipment capacities. Basis for the project calculations given in TableS.

For the above mentioned production schedule the cost of fixed capital and operating cost requirement have been estimated and reported subsequently. Various major elements, of fixed capital are land, design and engineering, equipment and operating cost includes cost of raw materials, utilities, manpower, etc. Tables 6- 1 0 show the cost involved in plant and machinery, land and building, utilities, manpower, annual operation and maintenance, respectively, for the above production schedule.

After calculation of the fixed and operating cost, total project cost is calculated. Calculations of the total cost of project" , cost benefit analysis, and payback period is shown in Tables I I - 1 3, respectively.

Conclusions

The industrial growth and urbanization have , tremendously increased the vehicle population and its

usage, this resulted in increased amount of pollutants released in the environment. The government stipulations and the emission standards are being made and are going to be more stringent in the coming days. As a combined effect of this the present vehicle on-road and new vehicles would require to adopt the exhaust emission control measures.

The catalytic converters are successfully applied for after-treatment of vehicular exhaust to reduce pollution. The demand of catalytic converter is increasing with vehicle population and is expected to increase many­fold if retrofit for in-use vehicles are considered. The advantages of NEERI's non-noble metal-based catalytic converter are simple manufacturing process, easily available, cheaper raw material, and indigenous plant and machinery. The vehicle specific design and retrofit

3

Table 6= Land and bUlldtng reqUIrement

Facility

Plant & machinery Fabrication W/S Evaluation facility Packaging and storage Office Total

Building ( sq ft)

5000 1 500 1 000 3000 2000

1 2500

Table 7- Plant and machinery

Equipment Required nos Cost (Rs lakhs) Slurry prep. vessel 2 5 Blender / Attritor 2 I Washcoating unit 2 2 Solution preparation vessel 1 0 2 Storage vessels 7 3.5 Forced air drier 2 5 Ovens 3 1 5 Furnaces 4 24 Coating vessels 2 Controlled atmosphere oven 7.5 Condensers 2 I

Mechanical workshop Lumpsum 5 Laboratory Lumpsum 1 2 Evaluation facility Lumpsum 30 Total cost 1 1 5

Table 8- Utilities requirement Power

Plant operation For 4-wheeler For 2-wheeler

Alumina washcoating Ceria precoating Catalyst synthesis and coating Promoter doping Activation Other Total

kWh/unit kWh/unit

0.64 0.05 0.48 0.03

0.52 0.04 0.36 0.03 0.22 0.02 0.44 0.03 2.65 0. 1 9

Cost of power including tax = R s 3 .60 lakh/y Water

Plant operation Alumina slurry preparation Catalyst preparation Total Cost of water Total utilities cost = Rs. 5.79 lakh/y

Lit.!shift 1 1 0.0 95.0 205.0 Rs 2. 1 9 lakh /y

734 J SCI IND RES VOL 60 SEPTEM BER 200 1

Table 9-Manpower requirement

Category No. of workers Rate, Rs/month

Supervisor 3 5000

Semisk il led 4 2550

Unski l led 20 2250

Total

Total manpower cost = Rs 25.27 l akh/y

Total salary Rs/month

1 5000 1 0200 45000 70200

Table 1 0- Annual operation and maintenance cost

Item Raw material I chemicals Uti l i ties Manpower Repairs Total

Rs in lakhs 1 254.97 5 .79 25 .27 5 .75 1 29 1 .53

Table 1 1 - Total project cost

I tem

Land Site development Bui lding (Civi l Work) Plant and machi nery

I ndigenous I m ported Erection I Foundat;;)I.

Technical know-how I Engineering fee Misc. assets

Electrical Deposits

Fire fighting I Others

Prel imi nary and preoperative Conti ngency provision Margin money for worki ng capital Total project cost

Rs in lakh

2.0 2.0 54.0 1 26.50 1 1 5.00

Ni l 1 1 .50 1 5 .00 20.00 1 0.00 5 .00 5 .00 20.00 40.00 80.74 360.24

Table 1 2- Cost benefit analysis

Instal led capacity 30000 units ( four-wheeler CC) 700()O ul l i ts ( two-wheeler CC)

Item four-wheeler CC two-wheeler CC

Sales Price proposed Basic cost of production Royally on sales price @ 3 per cent S . tax excise. octroi @ 24 per cent Sales overheads @ 5 per cent

Total cost of manufacturing Profit before tax Profit after tax

( Rs/unit) ( Rs/U nit )

5000 2000 1 733.59 1 250.53 1 50.00 60.0

1 200.00 480.0 250.00 1 00

3333.59 1 890. 5 3

1 666.4 1 1 09.47

1 1 66.49 76.63

Table 1 3- Pay back period

Total project cost = 360.24 Rs lakh

Year Cash accruals Cumulative Percenti le ut i l i satioll cash accruals o f capacity of (Rs in lakh) production

I 20 1 .79 20 1 .79 0.50 2 262.33 464. 1 3 0.65 3 3 22.87 787.08 0.80 4 363.23 1 1 50.23 0.90 5 363.23 1 5 1 3 .45 0.90 6 363.23 1 876.68 0.90

Pay back period = 1 .83 Y

poss ib i l i t i es ensure large m arket potent ia l for these catalytic converters in India .

F i n a nc i a l a n a l y s i s fo r c a t a l y t i c con v e rt e r manufacturing process shows that combined production of two- and four- wheelers is very cost effect ive with a reasonably good payback period of about 22 months .

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9

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I I

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