First in Africa liquid organic hydrogen carrier (LOHC) system - a pilot plant for renewable energy storage

by Philllimon Modisha , Gerhard Human & Dmitri Bessarabov, HySA Infrastructure

Table of Contents

• Background & Motivation

• Energy storage technologies

• Chemical storage

• Liquid organic hydrogen carriers

• 1st in Africa LOHC pilot plant

• Conclusions

Background & MotivationHySA Infrastructure CoC

Director: Dr Dmitri Bessarabov

Focus areas: Hydrogen Production

and Storage

Projects:

• Solar to Hydrogen (generation,

compression/ storage)

• Hydrogen storage on/in porous

materials (MOF, CNS)

• Chemical Carriers (Ammonia,

Formic Acid, LOHC)

• Composite Overwrapped

Pressure Vessels

Background & Motivation

LOHC

• New energy storage technologies for efficient and reliable Renewable Energy need to be developed.

• Conventional energy storage system have limitations such as: high costs, long lead time, self discharge, low energy density, safety, etc.

LOHC (liquid organic hydrogen carrier): Hydrocarbon molecule that store/ release hydrogen through catalytic hydrogenation/ dehydrogenation.

A SASOL produced Marlotherm SH® (mixture of dibenzyltoluene isomers) is classified as an excellent liquid organic hydrogen carrier (LOHC).

The high boiling point, low melting point and high H2 storage capacity (1m3 MSH= 624 m3 (57 kg) of H2 ) express Marlotherm SH ® as an excellent hydrogen carrier.

Aslam et al, Separation and Purification Technology 163 (2016) 140-144

Marlotherm SH: mixture of dibenzyltolueneisomers

Liquid Organic Hydrogen Carriers

Comparison of Chemical H2 storage systems

of Chemical H2 storage systems

Okada et al, Technical paper, Technology Development Unit, Chiyoda Corporation, Japan

Liquid Organic Hydrogen Carriers

Examples of LOHC Systems & Selection Criteria

Markiewicz et al, Energy Environ. Sci., 2015, 8, 1035

Selection of a suitable LOHC System

Hydrogen capacity (mass H2 / kg (liter) LOHC system)

Rate of charging/decharging (kinetics)

Selectivity and stability

Melting point and boiling point of carrier fluid

Compatibility to today‘s infrastructure for fuels

Safety aspects

Toxicology and ecotoxicology

Advantages of using LOHC using

LOHCs

© Air Products and Chemicals, Inc., 2010 Pub. No. 352-10-001-GLB

Not consumable like diesel or petrol, only H2 is released.Diesel like properties-easy to transportEfficient : 1kg LOHC= 2.2 kWhLong term storage without self dischargeSafe: Less toxic than diesel, No CO2 / CO emissions, non-flammableEasy to store at ambient conditions

Pumped hydro=100mCAES=2MPaH2 storage underground, 200 barH2 tube storage: 120 bar H2 Storage aboveground 18 bar

Comparison of long term energy storage technologieshnolog

Copyright 2015 Siemens AG

Compressed H2 gas vs LOHC

57 kg H2

1800 kg H2

1,9 MWh

60 MWh

Reversible hydrogen storage

Renewable energy storage

30 bar, 65.4 kJ/molPGM/Al2O3, 150 oC

1 bar, 65.4 kJ/molPGM/Al2O3, 300 oC

Hydrogenation pilot plant

Specifications• H2 consumption: 1000 NL/hr• Max operating pressure :40 bar• Max operating temperature: 300 °C

• Reactor volume: 50 litres• LOHC production: 1,3L/hr (3 kW/hr)• Hydrogenation grade:>99 %

Parametric effects on DBT conversion: Hydrogenation reaction

Liquid Carrier Stability Tests

Lab Scale Hydrogenation system Lab scale dehydrogenation system

Rapid hydrogenation and dehydrogenation for cycling stability

Specifications

• H2 consumption: 4000 NL/hr• LOHC production: 5,5 L/hr

Pre-Commercial System for Hydrogen Storage

Conclusions

• The LOHC hydrogenation plant was successfully commissioned and operational

• Pre-commercial quantities delivered to various customers

• High liquid feed flow decrease DBT conversion

• High DBT conversion can be achieved at 35 bar 180 oC and low flow rate.

• Or 30 bar 150 oC and recirculation to achieve even high degree of hydrogenation >99 %

Thank you!