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A feasibility analysis of hydrogen delivery system using liquidorganic hydrides

Ameya U. Pradhan, Anshu Shukla, Jayshri V. Pande, Shilpi Karmarkar, Rajesh B. Biniwale*

National Environmental Engineering Research Institute (NEERI), Council of Scientific and Industrial Research (CSIR), Nagpur 440020, India

a r t i c l e i n f o

Article history:

Received 8 June 2010

Received in revised form

17 September 2010

Accepted 19 September 2010

Available online 16 October 2010

Keywords:

Hydrogen storage

Hydrogen delivery

Cycloalkanes

Dehydrogenation

Hydrogen station

Feasibility analysis

* Corresponding author. Tel.: þ91 712 224988E-mail address: rb_biniwale@neeri.res.in

0360-3199/$ e see front matter ª 2010 Profedoi:10.1016/j.ijhydene.2010.09.054

a b s t r a c t

The paper discusses the techno-economic feasibility of a hydrogen storage and delivery

systemusing liquidorganichydrides (LOH).Wherein, LOH(particularlycycloalkanes)areused

for transporting thehydrogen inchemical bonded formatambient temperatureandpressure.

The hydrogen is delivered through a catalytic dehydrogenation process. The aromatics

formed in the process are used for carrying more hydrogen by a subsequent hydrogenation

reaction. Cost economics were performed on a system which produces 10 kg/h of hydrogen

using methylcyclohexane as a carrier. With proprietary catalysts we have demonstrated the

possibility of hydrogen storage of 6.8 wt% and 60 kg/m3 of hydrogen on volume basis. The

energy balance calculation reveals the ratio of energy transported to energy consumed is

about 3.9. Moreover, total carbon footprint calculation for the process of hydrogen delivery

including transportation of LOH is also reported. The process can facilitate a saving of 345

tons/year of carbon dioxide emissions per delivery station by replacing gasoline with

hydrogen forpassenger cars. There is an immense techno-economicpotential for theprocess.

ª 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

1. Introduction storage of hydrogen and utilization of hydrogen for energy

Hydrogen is a fascinating energy carrier. It can be produced

from water by electrolysis. Its conversion to heat or power is

simple and clean. When combusted with oxygen, hydrogen

forms water; hence no pollutants are generated. Hydrogen is

being pursued as a future fuel all around the world for auto-

motive applications in internal combustion engines and in

fuel cells [1,2]. Hydrogen-fuelled vehicles will use fuel cells,

which can provide much higher energy conversion efficiency

as compared to internal combustion (IC) engines with zero tail

pipe emissions [1]. Nevertheless, its storage and delivery

(or in-situ production) is still a challenge [3,4]

The four major factors on which conversion of automotive

fossil fuel economy to hydrogen economy will depend

include: bulk production of hydrogen, transportation of

hydrogen from production facility to fuelling station, onboard

5x410; fax: þ91 712 22499(R.B. Biniwale).ssor T. Nejat Veziroglu. P

generation [1]. Production of hydrogen from hydrocarbon via

steam reforming or auto-thermal reforming is relatively

developed [5]. Similarly, as evident from the literature, the

developments in the field of fuel cell or IC engines using

hydrogen as fuel have reached a considerable level [2].

Hydrogen being a very flammable gas, its storage and trans-

port involves several safety issues. The major safety issue is

wide span of lower and higher explosion limits for H2

concentration in air. Transporting hydrogen using high pres-

sure (typically 300e500 psi) cylinders for storage is not an

attractive option as it involves high pressure hazards and

potential explosion hazards. Carrying hydrogen in liquefied

form attracts an energy penalty and thus is not viable. These

problems can be overcome if hydrogen is either adsorbed on

materials such as carbon based materials [6], metal hydrides

[7,8], magnesium alloys [9] or boranes [10]. While developing

00; Mobile: þ91 9822745768.

ublished by Elsevier Ltd. All rights reserved.

i n t e r n a t i o n a l j o u rn a l o f h y d r o g e n en e r g y 3 6 ( 2 0 1 1 ) 6 8 0e6 8 8 681

such hydrogen storage materials, capacity of the material in

terms of weight and volume is an important factor to be

considered. With a limited capacity it would result in a weight

penalty and CO2 emissions associated with transportation.

Also the adsorption and desorption kinetics has to be suffi-

ciently fast to provide a continuous H2 supply. Another

important requisite is to transport hydrogen containingmedia

at close to atmospheric temperature and pressure.

A novel approach for the supply of hydrogen is through

liquid organic hydrides (LOH) using a catalytic reaction pair of

dehydrogenation of cycloalkanes such asmethylcyclohexane,

cyclohexane and decalin; and hydrogenation of correspond-

ing aromatics is a useful process for supply of hydrogen to

PEMFC [11e20]. This is one of the most promising methods

to store, transport and supply with in-situ generation of

hydrogen. The advantages of this system are: CO free

hydrogen at fuelling stations, reversible catalytic reactions,

recyclable reactants and products and relatively high

hydrogen contents (6e8wt%) [19]. Due to high boiling points of

cycloalkanes, the present infrastructure such as oil tankers

and tank lorries can be used for the long-term storage and

long-distance transportation of hydrogen in the form of LOH.

The proposed system of hydrogen storage using liquid organic

hydrides will serve the transportation of hydrogen from

production facility to fuelling stations. Whereas for onboard

storage of hydrogen other methods such as gas cylinders or

systems based on metal hydrides will be useful.

In order to implement the process of hydrogen delivery

using LOH technology, it is important to examine the techno-

economical feasibility of the method. This study targets the

feasibility of the hydrogen transportation and delivery using

LOH as hydrogen carriers and a dehydrogenation reaction as

means of producing hydrogen at fuelling stations. The present

approach particularly focuses on the transportation of

hydrogen from production facility to fuelling stations.

2. Description of process

Hydrogen is produced in refineries and chloroalkali industries.

This hydrogen can be reacted with aromatics to form cyclo-

alkanes. Cycloalkanes can be transported by lorries or pipe-

lines to fuelling station site, and can be stored in storage

tanks. A detailed description of the proposed process is given

in our earlier report [19]. At the fuelling station a subsequent

dehydrogenation reaction supplies hydrogen to fuel cell

vehicles and recycles back the toluene to the hydrogen

production facility. Literature reports high selectivity and

stability for some noble metal and non-noble metal-based

catalysts for the dehydrogenation reaction [11e20]. Hydroge-

nation and dehydrogenation reactions are well established.

However R & D efforts are being devoted towards the devel-

opment of appropriate systems for achieving these reactions

at low temperatures with low energy inputs.

Fig. 1 depicts a system based onmethylcyclohexane (MCH)

and toluene for the transportation of hydrogen. The system

boundary for the estimation of techno-economic feasibility

encloses the dehydrogenation setup at the fuelling station.

The MCH is fed to the reactor and exposed to the catalyst

heated at 350 �C. MCH on dehydrogenation give toluene and

hydrogen. These products are separated using a condenser.

Hydrogen is passed through a hydrocarbon trap. With subse-

quent compression the clean hydrogen, free from COx, can be

supplied to the fuel cell vehicles. Liquid products thus

obtained are then sent to an extractive distillation unit, which

separates aromatics from unreacted cycloalkanes which are

recycled back to their respective storage. Pure toluene is sent

back to the refinery for hydrogenation or can be directly sold

in the market as a solvent.

3. Results and discussions

Several factors are considered while proposing the above

discussed method for hydrogen transportation from

a hydrogen production facility to fuel station. These include:

� Use of various cycloalkanes

� Development of an effective catalytic system consisting of

active, selective and stable catalysts

� Development of reactors for effectively carrying out the

endothermic dehydrogenation reaction

� Easy product purification, particularly to obtain clean

hydrogen

� Economic estimations

� Carbon footprint of the system

3.1. Cycloalkanes as candidates for hydrogentransportation

Several cycloalkanes including cyclohexane, methyl-

cyclohexane, tetralin, decalin, cyclohexylbenzene, bicyclo-

hexyl, 1-methyldecalin, etc.may be used as a hydrogen carrier

as liquid organic hydrides. Each mole of cycloalkane has

potential to transport 3e6moles of hydrogen. This results into

a high hydrogen capacity between 3 and 7.5 wt% [19]. Catalytic

dehydrogenation of these cycloalkanes delivers the hydrogen.

The endothermic energy requirement for these reactions is in

the range of 64e69 kJ/mol of H2. This is much lower than

energy that could be obtained by oxidation of H2 (248 kJ/mol).

Hydrogen storage capacities of cycloalkanes, boiling points,

and endothermic energy required for dehydrogenation are

compared in Table 1. Due to high boiling points of cyclo-

alkanes, the present infrastructure such as oil tankers and

tank lorries can be used for the long-term storage and long-

distance transportation of hydrogen in the form of LOH [19].

Methylcyclohexane was selected for feasibility study as the

dehydrogenation product toluene is relatively safe solvent

as compared to benzene produced during dehydrogenation

of cyclohexane. Further, both the methylcyclohexane and

toluene are liquid at ambient conditions unlike naphthalene

produced by dehydrogenation of decalin. The ready avail-

ability of methylcyclohexane was also an important

consideration.

3.2. Development of catalysts for dehydrogenation ofcycloalkanes

The dehydrogenation of cycloalkanes can be effectively

carried out using the metal catalysts well dispersed on

Fig. 1 e Schematic diagram for hydrogen delivering plant delivering 10 kg/h using dehydrogenation of methylcyclohexane.

i n t e rn a t i o n a l j o u r n a l o f h y d r o g e n en e r g y 3 6 ( 2 0 1 1 ) 6 8 0e6 8 8682

a high surface area support [11e20]. The mechanism of

reaction involves adsorption of cycloalkanes on metallic site

with rapid or simultaneous abstraction of the hydrogen

atom via tetrahedral metal atom and formation of a pi-bond.

Thus the products of the reaction include hydrogen and

aromatics. Rapid removal of the hydrogen atom from the

active site and subsequent formation of molecular hydrogen

is an essential step to avoid the reverse reaction on the

Table 1 e Hydrogen storage capacity of various cycloalkanes, thdehydrogenation.

Storage Media Hydrogen storage capacity

wt% mol/L

Cyclohexane 7.2 27.77

Methylcyclohexane 6.2 23.29

Tetralin 3.0 14.72

cis-Decalin 7.3 32.44

trans-Decalin 7.3 31.46

Cyclohexylbenzene 3.8 17.63

Bicyclohexyl 7.3 32.0

cis-syn-1-Mehtyldecalin 6.6 29.31

trans-anti-1-Mehtyldecalin 6.6 28.52

catalyst’s surface. Several monometallic and bimetallic

catalysts are proposed for this reaction. A brief review for

the catalysts reported has been covered in our earlier report

[19]. A proprietary catalyst (i.e. NEERI DeH2) developed by

our group exhibits excellent activity in terms of hydrogen

production rates, 958 mmol/gmet/min as compared to the

best reported 744 mmol/Lcat/min for a continuous fixed bed

reactor system using MCH.

eir boiling points and endothermic energy requirement for

Boling point(�C)

Endothermic dehydrogenationenergy (kJ/mol of H2)

80.7 þ68.8

101 þ68.3

207 þ64.2

193 þ64.0

185 þ66.7

237 þ65.9

227 þ66.6

213.2 þ63.9

204.9 e

i n t e r n a t i o n a l j o u rn a l o f h y d r o g e n en e r g y 3 6 ( 2 0 1 1 ) 6 8 0e6 8 8 683

Another important aspect of catalyst design is use of

support for structured catalyst. Besides requiring a high

surface area of the support, its structured nature is also

important. Using Al2O3 or carbon pellets placement of catalyst

in the reactor is difficult, particularly for heating the catalyst,

except in the case of a packed bed reactor. As explained in the

next section, if plate type heaters are used then the contact

between heater and pellets is not continuous and results in

poor heat transfer to the catalyst. Earlier, we have reported the

use of carbon cloth and alumite plates as support for metal

catalysts [18,19]. This structured catalyst is suitable for

placement of catalyst in the reactor.

3.3. Development of reactors for catalyticdehydrogenation of cycloalkanes

Dehydrogenation of cycloalkanes being an endothermic

reaction demands supply of heat. The catalyst’s surface is

thus required to be at temperatures in the range of 300e400 �C.Since the reactant, i.e. methylcyclohexane, is fed to the

reactor in liquid form the surface temperature of the catalysts

may be lowered by losing energy in vaporizing the reactant

and product. However, in the case of vapor phase reaction,

wherein the cycloalkanes are introduced as vapors, the

contact between reactant and solid catalysts may be poor. In

our work we have used two different types of reactors e

namely a packed column reactor and an advanced spray-

pulsed reactor. The packed column reactor is simple to

operate and particularly useful when the source of heat is

a solar concentrator.

It is reported in the literature including our earlier studies

[16e20] that creation of unsteady state conditions on the

surface of the catalysts helps in improving the activity and

stability of the catalysts for dehydrogenation of cycloalkanes.

Several attempts including superheated film conditions,

spray-pulsed reactors, etc. have been reported for creating

unsteady conditions. We have used a spray-pulsed reactor, as

described in detail elsewhere and briefly herein, to create

alternatewet and dry conditions over the catalyst surface. The

catalyst is kept on a plate type heater and the reactant is

introduced as an atomized spray over the catalysts. A fine

nozzle installed at the top of the reactor is used for creating

the atomized spray and for injecting cycloalkanes at

a controlled injection pulse frequency and pulsewidth. During

the injection step, reactant reaches the heated catalyst’s

surface in fine droplets and evaporates to form a dense vapor

phase in close vicinity to the catalyst surface. This improves

the catalyst-reactant contact. During the interval between two

injection pulses, i.e. dry step, the product and unreacted

reactant gets removed from the surface of the catalyst. The

alternate wet and dry conditions thus help in keeping the

catalyst’s surface clean and active for longer stability of

the catalyst. Also, the surface of the catalyst can be main-

tained at high temperature favoring the dehydrogenation

reaction. Using several reactors in combination with a time

phase lag between injections would provide the hydrogen on

a continuous basis.

Selection of the reactor is based on the application for

which the hydrogen is required and the method used for

heating the catalyst. In the case where the solar concentrators

are used for heating the catalyst, then tubular packed bed

reactors are useful. Even a microchannel reactor could be

a good option. Whereas when electrical heaters are used,

either reactor can be employed.

The catalysts on a laboratory scale have been evaluated for

their hydrogen evaluation rate at various conditions. The

reaction conditions were optimised for an advanced spray-

pulse injection reactor. The optimum temperature for the

dehydrogenation of cycloalkanes is in the range of 300e350 �C.In our previous study we have reported optimization of the

pulse injection frequency and pulse width for feeding cyclo-

alkanes to the reactor [18,20]. Accordingly for the catalysts

referred in this study for dehydrogenation of methyl-

cyclohexane the best feed conditions obtained were pulse

injection frequency of 0.33 Hz and pulse width of 10 ms.

3.4. Mass and energy balance on the process

The process of delivering hydrogen using LOH is described in

Fig. 1. In order to establish the flow of rawmaterials, products,

product separation and various process parameters, a detailed

mass and energy balance for the process has beenworked out.

The basis for calculations was taken from laboratory data (our

own work) on catalyst performance for generating hydrogen

at 10 kg/h with continuous operation of 100 h. As depicted in

Fig. 1 the mass balance has been carried out for targeted

delivery of 10 kg/h of hydrogen. The delivery pressure is about

1e1.2 bar and the temperature is ambient. In order to main-

tain the flow through the reactor, hydrogen is used as a sweep

gas. Initially an external source of hydrogen may be used to

start the reaction. Once the system is able to generate the

hydrogen, a part of the hydrogen is recycled back as the sweep

gas. The reactor is designed to generate about 12 kg/h of

hydrogen. Out of the total 12 kg/h of hydrogen generated, 10

kg/h is supplied to the vehicles after compression. The

balance of 2 kg/h of hydrogen is recycled back to the reactor,

after compression, at a pressure of 2.5e3 bar. Estimated

requirement of MCH at the conversion efficiency of 90% is 216

kg/h. The products hydrogen and toluene are separated by

using a condenser. The condensable product contains about

22 kg/h of MCH. The separation of MCH and toluene is carried

out in an extractive distillation unit. An evaporative loss of

0.3% from storage of MCH and toluene has been estimated by

considering the maximum ambient temperature of 40 �C.Similarly, other process losses have been estimated as 0.1%

and evaporative losses during transportation is estimated as

0.5%. This amounts to a total loss of MCH of about 0.9%.

The energy requirement for the hydrogen delivery process

consists of energy for carrying out the reaction at 320e350 �C,energy required for pumping MCH to the reactor, energy for

the condenser, energy for extractive distillation, energy

required for compression of hydrogen, and for process

equipment. When the required energy is compared with the

energy that can be evolved by hydrogen combustion, an

energy efficiency factor can be calculated using:

Energy efficiency ¼ Energy generation potential of

hydrogen supplied/Total fossil fuel energy supplied.

Based on the energy balance estimates are given in the

Table 2. The total energy consumption for production of

hydrogen during is 5.10 kW/kg and the energy that can be

Table 2 e Energy efficiency estimation.

Sr. No. Description Quantity

A) Calculations for energy Consumption during the process

1. Methylcyclohexane requirement (kg/day) 3465.5

2. Energy requirement for dehydrogenation

a) Heat of reaction @62 kJ/mol (kW) 547.07

b) Energy required for pumps and instrumentation (kW) 8.53

c) Energy required for chillers (kW) 54.4

d) Energy required for illumination and plant accessories (kW) 13.2

Sub Total (a to d) (kW) 623.2

3. Energy required for separation of unconverted methylcyclohexane

and toluene afterreaction (kW)

112

4. Energy required for compression of hydrogen (kW) 80

Grand total of energy consumption (kW) 815.2

In terms of per kg of hydrogen the energy required (kW/kg) 5.10

B) Energy production by hydrogen made available through LOH

5. Total hydrogen produced (kg/day) or 160

In terms of (kmol/h) 4.96

6. Energy that can be released by hydrogen (kJ/mol) 242

7. Gross energy available by hydrogen produced (kW/h) 333.65

8. Total energy available at 60% efficiency of fuel cell stacks (kW/h) 200.19

9. Total energy available in 16 h (kW) 3203

In terms of per kg of hydrogen the energy available (kW/kg) 20.02

10. Ratio of energy generated/energy consumed

a) Without considering the energy requirement for compressor 4.36

b) With considering the compressor energy need 3.92

i n t e rn a t i o n a l j o u r n a l o f h y d r o g e n en e r g y 3 6 ( 2 0 1 1 ) 6 8 0e6 8 8684

made available by hydrogen is 20.02 kW/kg. This indicates

a favourable energy ratio in terms of energy produced/energy

consumed. The energy efficiency ratios when the compressor

is not considered and when it is considered are 4.36 and 3.92

respectively.

The major energy requirement out of the total energy for

dehydrogenation of methylcyclohexane is for the heat of

reaction. This requirement is about 67.12%. Separation of

products and unreacted reactant contributes to 13.7% of the

total energy requirement. This clearly indicates that the scope

of energy reduction is rather marginal as most of the energy

required is for heat of reaction. Energy efficient pumps and

separation units could be designed for reduction in the energy

requirement.

3.5. Financial feasibility analysis of the manufacturingprocess

Cost-effectiveness analysis was carried out for hydrogen

delivery using dehydrogenation of methylcyclohexane.

Assuming the cost of methylcyclohexane at the rate of 0.97

USD/kg and the selling price for toluene considered about 0.89

USD/kg the cost of hydrogen production at present estimates

would be approximately 5.33 USD/kg delivered at the fuelling

station.

The following assumptions were considered:

� 10 kg/h of hydrogen production.

� 300 working days per year.

� 16 h working per day.

Most importantly the cost of hydrogen delivery will not

increase significantly even if thedistanceofdelivery is increased.

Therefore the hydrogen delivery using LOH is a cost-effective

process having favourable energy efficiencies. The technology,

which is offered, should be based on realistic assessment of cost

and benefit, keeping in view the technical and economic feasi-

bility. Many of the potential benefits of this technology assure

sufficient incentives to themanufacturers to achieve the desired

goals. A key component, therefore, must be the cost-effective

production of Hydrogen to ensure compliance with standards.

The cost of each systemcomponent includes the cost of raw

material, manufacturing, assembly and mark-up. Mark-up

refers to the additional cost percentage to account for payment

to workers, overhead expenses and profit. The final resulting

“cost” is thus actually a projected “price” of the hydrogen

generated at the fuelling station. In addition, theprojected cost

of hydrogen to the consumer (potentially an FCV motorist) is

provided in this report, with inclusion of taxes. The detailed

financial analysis is done considering the various cost

components involved in theprocess to arrive at optimumplant

capacity. As the capacity of the plant (amount of hydrogen

produced) increases, the fixed capital and the operating capital

both increase but evidently an increase in fixed capital is not as

proportional as increase in theoperating capital.With increase

in the capacity of the plant, the payback period decreases.

From the cost estimations, carried out on different plant

capacities, it has been observed that the capacity of a plant of

10 kg/h is suitable with respect to demand and economic

criteria. A total of 300working days in a yearwith 16 hworking

per day were considered for the calculation of equipment

capacities. For the above mentioned production schedule

the cost of fixed capital and operating cost requirement

has been estimated and reported subsequently. Tables 3e6

depict the cost involved in plant and machinery, electrical

power requirement, manpower, and annual operation &

Table 3 e Plant and machinery taking 1 USD [ 47 Rs.

Equipment RequiredNo.

Cost(Thousand USD)

Reactor 2 22.55

Storage tanks 3 17.23

Resistance temperature

Detector (RTD)

6 6.38

Pressure gauge 4 1.70

Level transmitter 4 0.85

Flow meters 6 1.28

Control valves 2 3.83

Frequency controller 1 2.13

Safety interlocking 2 2.13

Gas chromatograph 1 13.83

Extractive distillation columns

(For MCH & toluene separation) 2 12.77

Distillation column 1 4.26

Air compressor 1 0.43

Water pump and Storage 1 0.96

Fuel pumps 10 0.74

Chiller 1 6.38

Condenser (heat exchanger) 2 12.77

Phase separating vessel 2 0.85

Total 111.06

Table 5 e Manpower requirement.

Category No. ofPeople

Total SalaryUSD/Month

Supervisor 1 255.32

Operators (skilled) 2 340.43

Cleaners (unskilled) 2 212.77

Total 5 808.51

Annual man power cost (Thousand USD) 9.70

# Man Power calculation is based on Indian Standards. It might

differ from country to country.

i n t e r n a t i o n a l j o u rn a l o f h y d r o g e n en e r g y 3 6 ( 2 0 1 1 ) 6 8 0e6 8 8 685

maintenance cost respectively. The cost of plant and

machinery has been estimated on the basis of prevailing costs

in the local market for fabrication of various equipments. The

details of equipment are given in Table 3 and a schematic of

the process flow sheet without finer details in depicted in

Fig. 1. Based on the local sources the plant andmachinery cost

is estimated at 11106 USD. As shown in Table 4 the cost esti-

mate for energy requirement for per day operation for 16 h is

178 USD/day. Table 5 shows manpower calculations using

Indian standards. Production cost is calculated by finding

annual operation and maintenance cost, utilities cost and

manpower costs as shown in Table 6. Total project cost was

calculated as shown in Table 7 as 327000 USD.

According to the break-up of total cost of the plant about

37.36% cost is of plant and machinery. The second major

component of the cost is working capital contributing 18.07%.

The implication of fluctuations in the price of methyl-

cyclohexane may affect the working capital cost. Whereas

Table 4 e Electric power requirement cost of electricity(per unit i.e. kW-h)[ 0.149 USD/kW-h (Indian standards).

Plant Operation No. of Units Power(kW-h/day)

Energy for dehydrogenation 1 Heater & 8 Pumps 502.50

Energy for hydrogenation 1 Heater & feed pumps 500

Energy for lighting and

illumination

Lump Sum 13.2

Chiller and instrumentation 1 54.72

Extractive distillation 3 80

Distillation of hydrogenation

products

1 48

Total (kW-h/day) 1198.42

Power Cost (USD/day) 178.49

technical know-how/engineering fees, cost of plant and

machinery would remain the same for the same capacity of

the plant. However cost reduction in the plant andmachinery,

preoperative and contingencies cost may be attempted to

reduce the total cost of the project.

Out of the total working capital themajor cost is due to raw

materials (69.5%) and utilities (22.6%). The cost of raw mate-

rials was considered as the cost ofmethylcyclohexane and the

basic cost of hydrogen for a year. The cost of hydrogen if to

be purchased from hydrogen production facility would be

approximately 1.5 USD/kg. This assumption is based on the

projected cost of the hydrogen from coal gasification or

hydrocarbon reforming as available in the open literature.

The pricing of hydrogen as projected by different reports in

the literature ranges between 2 and 5 USD/kg (untaxed). The

cost of CO2 sequestration in case of hydrogen production from

steam reforming would generally offset the price of hydrogen.

Based on the estimated cost of production of hydrogen at

fuelling station using dehydrogenation of methylcyclohexane

(including re-hydrogenation of toluene for subsequent cycles)

a comparison has been carried out for pricing of hydrogen.

The sales price of hydrogen (including taxes) to the customer

was varied from 7 to 7.75 USD/kg. Effect of this variation on

cumulative cash accruals is depicted in Fig. 2. In order to

obtain a reasonable payback period, price of hydrogen was

selected as 7.45 USD/kg. Cost benefit analysis as seen in

Table 8 indicates that hydrogen if sold at 7.45 USD/kg, results

in an annual profit of 58770 USD (after tax). The effective

payback period was calculated based on the assumption that

Table 6 e Annual operation & maintenance and cost ofhydrogen production.

Item Cost (inThousand USD)

Raw Material/Chemicals. 164.51

Cost on Utilities. 53.55

Annual Manpower cost 9.70

Annual cost of Repairs. 5.55

Depreciation on P&M @ 10% 11.11

Depreciation on L&B @ 5% 1.06

Interest on capital

(@ 25% of total capital) @ 12%

10.44

Total annual expenditure for 48,000 kg

hydrogen production.

255.92

Therefore the cost of hydrogen production is 5.33 USD/kg

Table 7 e Total project cost.

Item Costs(Thousand USD)

Land (on existing fuel pumps) Nil

Site development 21.28

Building and civil work 5.32

Plant and machinery:

Indigenous 111.06

Imported Nil

Erection/Commissioning (10% of P &M) 11.10

Technical know how and engineering fee 53.19

Misc. Assets:

Electrical Fittings 2.17

Deposits 6.38

Fire fighting/Others 4.22

Preliminary and preoperative 21.28

Contingency provision 31.91

Margin money for working capital

(3 Months O&M)

59.09

Total cost of Project 327

Table 8 e Cost benefit analysis.

Item Cost USD/kg

Sales price of hydrogen (USD/kg) 7.45

Basic cost of production 5.33

Royalty on sales price @ 1% 0.07

Local tax, octroi @ 5% 0.27

Sales overhead 0.03

Total cost of manufacturing 5.70

Profit per kg of hydrogen 1.75

Annual profit before tax (Thousand USD) 83.96

Annual profit after tax @ 30%(Thousand USD) 58.77

i n t e rn a t i o n a l j o u r n a l o f h y d r o g e n en e r g y 3 6 ( 2 0 1 1 ) 6 8 0e6 8 8686

the fuelling station will operate at 50, 70, 95 and 100% capacity

for the first, second, third and fourth year respectively. From

the fourth year of operation 100% capacity utilization is

expected. The cash inflow estimates shown in Table 9 results

in a payback period of 6.41 years.

4. Comparison with hydrogen carryingpipelines

When the LOH based system is compared with a pipeline

transport system for hydrogen, it can be seen that pipeline

installation requires huge investments per km of pipeline.

According to estimates provided by NREL, DOE, USA [21] and

ANL, USA [22] the hydrogen pipeline cost may be of the order

of 400000 USD per mile. This cost may be higher for the

pipelinewith diametermore than 3 inches (0.075m). Although

0

100

200

300

400

500

600

0 2 4 6 8 10Number of years

Cum

mul

ativ

e ca

sh a

ccru

al (1

000

USD

)

7.0 USD/kg

7.25 USD/kg

7.45 USD/kg

Project Cost

7.75 USD/kg

Fig. 2 e Variation in cumulative cash accruals for varying

sales price of hydrogen.

it is argued in the literature that the variation in pressure

simply can vary the hydrogen storage/delivery capacity of

pipeline, compression of hydrogen is an energy intensive

operation. Whereas calculations show LOH based systems

with 10 kg/h hydrogen delivery had an overall installation cost

of approximately 327000 USD (as shown in Table 7). This

includes all preoperative as well as three months operative

costs. Unlike in the case of pipelines, the costs of trans-

portation do not vary largely depending on the distance if LOH

approach is used. Use of pipelines has limitations when the

distance of transport is high. For an example, in this case

wherein the hydrogen transportation upto 300 km is consid-

ered the approximate cost of hydrogen pipelines could be of

the order of 800 million USD. Moreover due to high flamma-

bility of hydrogen, transportation of using pipelines is risky

as well.

5. Reduction in total carbon footprintemission

Estimation of total carbon footprints is an increasingly

important evaluation tool for decision making. Especially

applied during the planning phase, it can pinpoint process

steps with a high environmental impact and thus, provide

guidance towards optimising the actual technology imple-

mentation. One of the main goals of this study was the

assessment of the environmental impact of hydrogen fuel

transported in the form of liquid organic hydrides.

Table 9 e Pay back period Total project cost [ 327Thousand USD.

Year Percentageproductioncapacityutilization

Net CashInflow

(Thousand USD)

CumulativeCash Inflow

(Thousand USD)

1 50 29.38 29.38

2 70 41.14 70.52

3 95 55.83 126.36

4 100 58.77 185.13

5 100 58.77 243.90

6 100 58.77 302.68

7 100 58.77 361.45

8 100 58.77 420.23

Payback period ¼ 6.41 years.

Table 10 e Annual savings in Carbon footprint assuming total distance of travel for transport once [ 300 km, mileage ofa fuel cell car [ 73.6 miles/kg of hydrogen and gasoline car mileage [ 15 km/l.

Sr. No. Description Value

A Dehydrogenation and hydrogenation processes

1 Number of electrical units consumed (kW/day) 1198

2 Units per year (kW/Year) 359,526

3 Amount of CO2 emitted in the process of dehydrogenation and hydrogenation (kg/year) 503,336

B Transportation of LOH

4 Average distance travelled (km/year) 25,800

5 Mileage (km/l) for a tanker carrying LOH 4

6 Total diesel consumed (l/year) 6450

7 Amount of CO2 emitted in the transport (kg/year) 17,415

C So Total Carbon footprint of the process (kg/year) [ (3) D (7) 520,751

8 Hydrogen produced in one year (kg/year) 48,000

9 Distance that could be travelled by fuel cell vehicle (mile/year) 353,280

10 CO2 being evolved by normal Gasoline vehicle to travel the same distance (kg/year) 866,713

D CO2 that can be saved (kg/year) 345,962

i n t e r n a t i o n a l j o u rn a l o f h y d r o g e n en e r g y 3 6 ( 2 0 1 1 ) 6 8 0e6 8 8 687

The function of the product, i.e. hydrogen, is to serve as

fuel formotor vehicles. This produceswaterwhen used as fuel

in an FCV that lead to zero tail gas emissions. The total CO2

emissions calculated for LOH system include the CO2 emis-

sions attributed to the energy requirement for dehydrogena-

tion and emissions from transportation of LOH using tank

lorries. Furthermore, if the distance travelled by the FCV is

compared to that of a gasoline powered vehicle, the total

carbon footprint reduction is remarkably high for LOH based

hydrogen transport and delivery system. As detailed in Table

10, for the basis for estimation of CO2 emissions avoided

a distance of 300 km for hydrogen transportation is consid-

ered. The CO2 emissions due to transportation of LOH and

dehydrogenation reaction at a fuelling station have been

estimated about 17,400 and 503,300 kg/year. This amounts to

total carbon foot print of 520 tons/year. A gallon of gasoline

equivalent (gge) of hydrogen is about 1 kg. A fuel cell driven

passenger car would cover about 74 km per kg of hydrogen. It

is considered that a gasoline driven car gives mileage of 15

km/l of gasoline. Using a proper emission factor for CO2

emissions from gasoline driven cars, for a total car-kms

travelled of 350,000 km/year the carbon foot print would be

866 tons/year. Considering that a fuelling station with 10 kg/h

of hydrogen delivery capacity would serve to fuel cells vehi-

cles there by avoiding use of gasoline, the carbon foot print

reduction of 345 tons/year can be achieved. This amounts to

a 40% reduction in CO2 emissions as compared to normal

gasoline driven vehicles by enabling the use of fuel cell vehi-

cles through supply of hydrogen using LOH system.

6. Conclusions

Several advantages associated with liquid organic hydrides

(LOH) for storage and supply of hydrogen include relatively

high hydrogen storage capacity, carrying hydrogen in chemi-

cally bonded form at near ambient conditions, easy delivery of

hydrogen, and purity of hydrogen for applications in fuel cell

vehicles. In view of LOH as a potential hydrogen delivery

option, the economic analysis carried out reveals a high

feasibility. The near future cost of hydrogen for a plant of

capacity of 10 kg/h has been estimated as 7.47 USD/kg

including all expenses and taxes. Although the analysis is

carried out in an Indian context, it nevertheless is useful for

estimating the potential for other countries. Further, estima-

tions of carbon footprint exhibit the possibility of a large

saving on carbon emissions by facilitating hydrogen supply

using this option. In view of the excellent activity of our

proprietary catalyst the option is highly feasible.

Acknowledgements

Financial support received from Ministry of New and Renew-

able Energy, New Delhi is acknowledged. The authors Ms.

Anshu Shukla and Ms. Jayshri Pande would like to acknowl-

edge CSIR for their Senior Research fellowships.

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