Chemical Technology May 2016
ERWAT EXCELLENCE IN WASTEWATER
Consistent quality requires consistent excellence ...
Serving both the public and private sectors, ERWAT promotes a healthy environment by providing cost-effective wastewater treatment solutions through innovative technologies. It specialises in sustainable, quality wastewater services, backed by focused technical, maintenance and engineering services. An ISO/IEC 17025 accredited laboratory renders a wide variety of specialised analyses, while industrial wastewater quality management assessments and advice are also offered. ... in every area of wastewater management.
East Rand Water Reg. No. 1992/005753/08 (Association incorporated in terms of section 21) GPS Co-ordinates: S 26° 01’ 25.8” and E 28° 17’ 10.0”
Address: Hartebeestfontein Office Park, R25, Bapsfontein/Bronkhorstspruit, Kempton Park. Tel: +27 11 929 7000 E-mail: mail@erwat.co.za www.erwat.co.za
pemarketingA13900
22
6
16
20
Contents
4
REGULAR FEATURES 3 Comment by Anthonie Cilliers
12 WACKER Silicones – New applications for silicone films
German chemical company, WACKER, operates globally with a network of production sites spanning all key regions, in Europe, the Americas and Asia. WACKER’s silicone division is one of the largest silicone manufacturers worldwide. Its portfolio ranges from silicone fluids, emulsions, resins, elastomers and sealants to silanes, silane terminated polymers and pyrogenic silica. by Glynnis Koch 16 Focus on corrosion and coatings RENEWABLES 20 Rehabilitation in a time of coral bleaching Divers consider the Great Barrier Reef, off the far northern coast of Queensland, Australia, to be one of the greatest destinations for viewing coral anywhere in the world. At 2 300 km long, the system is the largest living thing on earth, and it is dying. by Gavin Chait MINERALS PROCESSING AND METALLURGY 22 Volatiles removal from solids – An introduction to devolatising Devolatilisation is a mandatory step in the manufacturing of many commercial solids ranging from pharmaceutical products to waste streams. Excessive levels of residual solvents, monomers or other volatiles can create fires or explosions in subsequent processing or transportation steps, as well as discontinuities in product appearance. The residual solvents or monomers may also be odoriferous at very low concentrations, creating end user concerns. by Joe Bonem, Polymers and Process Engineering Consultant 25 Focus on minerals processing and metallurgy
28 SAIChE IChemE News
29 SAIChE IChemE ‘spotlight’
31 Et cetera
Transparency You Can See Average circulation (Q1 Jan – Mar 2016) 3 630
32 Sudoku No 114 and solution to No 113
COVER STORY 4 MSA – Harnessing new technologies to produce exceptional protective equipment ‘ChemTech’ recently paid a visit to the offices of MSA The Safety Company and spoke to Colin Oliver, director Sub-Saharan Africa region, about the company’s role and contribution to the safety market in South Africa and other African countries. WATER TREATMENT 6 The potential of water re-use in shale gas bed fracturing in South Africa New water treatment technologies and new applications of existing technologies are being developed and used to treat shale gas produced water. The treated water can be reused as fracturing make-up water, irrigation water, and in some cases even drinking water. New approaches and more efficient technologies are needed to make treatment and re-
Chemical Technology is endorsed by The South African Institution of Chemical Engineers
and the Southern African Association of Energy Efficiency
use a widespread reality. by Carl Schonborn, Pr Eng
DISCLAIMER The views expressed in this journal are not neces- sarily those of the editor or the publisher. Generic images courtesy of www.shutterstock.com
10 Focus on water treatment
CORROSION AND COATINGS
1
Chemical Technology • May 2016
http://www.chemicaltechnologymagazine.co.za/
A radar beam focused like a laser! The future is 80 GHz: a new generation of radar level sensors
The latest cutting-edge technology from the world leader: the unsurpassed focusing of VEGAPULS 64. This enables the radar beam to be targeted at the liquid surface with pinpoint accuracy, avoiding internal obstructions like heating coils and agitators. This new generation of level sensors is also completely unaffected by condensation or buildup and has the smallest antenna of its kind. Simply world-class!
www.vega.com/radar
COMMENT
by Dr Anthonie Cilliers, Pr.Eng The case for nuclear power
I am extremely pro-nuclear, not because I work in the industry. I work in the nuclear industry because I cannot see a viable alternative for supplying the country with clean energy. Maybe I am missing some- thing; I hear on a daily basis about renew- able energy being able to supply all the needs of the country. When I do the calcula- tions, however, things simply don’t add up. Based on information from the US Energy Information Administration (eia.gov) the capac- ity factor for nuclear was 92,2 % in 2015 in the US, with wind at 32,5 %, PV at 28,6 % and solar thermal at 22,7 %. This is average data over the entire year for a very large country, so the notion that the wind is always blowing somewhere simply is not true. To put this data into perspective we need to calculate how to install a stable MW of elec- tricity from these sources. One MW installed wind will provide on average 325 kW over the entire year, 1 MW PV 286 kW, thermal solar 227 kW and nuclear, 92 2 kW. This also means that for an equivalent wind and nuclear MW, 2,84 times the capacity of wind needs to be installed. (For solar this factor is 3.22, for PV and 4.06 for thermal solar.) Since these sup- plies are still intermittent, an equal amount of storage still need to be installed, thus these storage mediums are, in my estimation, 80 % efficient, at best. This brings the factor for wind to 3,408, PV to 3,864 and thermal solar to 4,872. When comparing cost, we are talking about cost per installed kW. We then translate that to kWh to determine the cost per unit of electric- ity. From my calculation above it is clear that installed kW does not translate directly to kWh. If we make the (very incorrect) assumption that the storage medium costs the same per kW of storage as the generating capacity, we see that the cost to install a nuclear equivalent kW of wind will rise to 4,408 times that of the peak
capacity installation cost. (For PV this factor is 4,864 and for thermal solar, 5,872.) While some claim that the cost of wind en- ergy can be as low as 57c/kWh, the real base load price rises to R2,51/kWh, for PVs, R2,77/ kWh and for solar thermal, R3,35/kWh. This is if I assume all sources can provide a kWh at 57c/kWh when available. Unfortunately, reliability has a price tag. The other argument is that renewable en- ergy (RE) can augment gas turbine electricity production. Here the calculation is simpler. If, for every 1 MW of gas turbine supply we install 1MWof RE, it will simply result in a reduction of one’s gas bill by 32,5 %, 28,6 % and 22,7 % re- spectively. Based on the additional capital cost of the installations I am not sure if this viable. Germany’s case is an interesting one. With a total installed base of 39 698 MW of solar PVs in the country, the capacity factor in Germany for PVs is at 14 %. That results in an average capacity of 5 557,72 MW over a year. With storage of 6 000 MW being 80 % efficient, they would have 4446,18 MW of solar base load capacity available. Because of this, this massive PV capacity only contributes 6,2 % of the consumed kWh in the country. I am not against RE. Not at all, I believe it has a place, but when I hear comments that the uncertainty of the price of nuclear power will prevent us from moving forward, I cannot help but wonder how the other energy sources costs stack up. Nuclear power has unique capabilities that make it impossible even to consider a low carbon energy future without it being part of the mix. I would welcome any comments. I truly want to find solutions for the country to be real and effective.
Published monthly by: Crown Publications cc Crown House Cnr Theunis and Sovereign Streets Bedford Gardens 2007 PO Box 140 Bedfordview 2008 Tel: +27 (0) 11 622-4770 Fax: +27 (0) 11 615-6108 www.crown.co.za Consulting editor: Carl Schonborn, PrEng Editor: Glynnis Koch BA(Hons) Comms, LDipBibl Advertising: Brenda Karathanasis Design & layout: Colin Mazibuko E-mail: chemtech@crown.co.za Website:
Circulation: Karen Smith Publisher: Karen Grant
Deputy Publisher: Wilhelm du Plessis Director: Jenny Warwick Printed by: Tandym Print - Cape Town
Email Dr Anthonie Cilliers at: Anthonie.Cilliers@nwu.ac.za, or telephone: +27 18 299 1312.
3
Chemical Technology • May 2016
MSA – Harnessing new technologies to produce exceptional protective equipment
‘ChemTech’ recently paid a visit to the offices of MSA The Safety Company and spoke to Colin Oliver, director Sub-Saharan Africa region, about the company’s role and contribution to the safety market in South Africa and other African countries.
L ast year the company celebrated its 75th anniversary, the South African branch being the second oldest, next to the head office in Pittsburgh, USA, which celebrated its centenary last year. Presently R&D takes place in the Ryan Laboratory in Pitttsburgh, the laboratory named after John T Ryan, the founder of the company. Existing products are constantly being improved and in- novated, which, Oliver told us, is the main reason MSA safety products are regarded as the most reputable and reliable brand available, both in this country and further afield, in Nigeria and Ghana, as well as in newer, expand- ing markets such as Angola, Mozambique and Tanzania. The mainstay of MSA in South Africa is the Oil, Gas and Petroleum (OGP) sector, which, Oliver said, makes up 40 – 50 % of the company’s total business. Together with the mining sector, they make up 70 – 80 % of the total. The rest of the business is in utilities and general industries. Range of products Oliver explained that the safety and fire and emergency markets have, together, a large footprint in sub-Saharan Africa. Overall, the top-ranking product is the range of self- contained breathing apparatus (SCBA) or devices such as the G1 SCBA which offers integrated and enhanced solutions such as built-in telemetry devices, monitors to measure air capacity, built-in communication units and
flashing alarms. Rechargeable batteries are now available for the central power systems which run all the electronics. No matter which button is pressed on the control module of the device, necessary information displays. Recent in- novations mean that the G1 SCBA provides more data and functionality than ever before and the heads up display provides clear and easy to understand/interpret informa- tion. Furthermore, it has integrated technology such as Bluetooth, RFID, Near Field Communication (NFC), and long-range radio, for future expansion. The MSA AirXpress 2 Fire is a new, economical SCBA with customisable configurations, allowing usage in different first responder applications and as such is ideally-suited to firefighting, rescue operations, escape scenarios, confined space entry and for ‘search and rescue’ missions. The unit has amodern design and features an ergonomic back plate, designed for unrestricted movement, while the chest strap prevents any slipping of the shoulder harness. The carrier is made with glass fibre-reinforced polyamide to withstand high heat and flames. It boasts an optional manual bypass function which increases the airflow in extreme environments. Other popular products Fall protection equipment, such as full body harnesses, self- retracting devices and energy-absorbing lanyards, confined
4
Chemical Technology •May 2016
COVER STORY
To do this, MSA staff is especially trained and certifi- cated with the qualification, BOSIET (Basic Offshore Safety Induction Emergency Training), which includes range of knowledge and skills relevant to working offshore and the proper emergency response procedures, including safety induction, fire safety and self-rescue, helicopter safety and escape, and sea survival. Ethisphere Institute award for standards of ethical business practices Last, but by no means least, when asked about MSA’s recent international award for ethical business practices, Oliver explained that the company was yet again, for the second year in succession, recognised by the Ethisphere Institute, the global leader in defining and advancing the standards of ethical business practices, as a 2016 World’s Most Ethical Company ® . There is no doubt that this basic tenet contributes, on a daily basis, to MSA’s success worldwide, a fact that Oliver is at pains to reiterate.
space products and lifelines and climbing systems, are among the most sought after products in MSA’s ranges. In addition, MSA recently acquired Latchways plc, a UK-based provider of innovative fall protection systems and solutions thereby significantly broadening its existing line of fall pro- tection products and strengthening the company’s position in the global fall protection market, estimated at between US$1,5 and US$2,0 billion globally. Portable gas detectors and other Fixed Gas & Flame Detection (FGFP) monitors and detectors are also used on a large scale in the safety field to detect sparks and open fires or flames, and, of course, explosive gases, particularly in the OGP sector. An acoustic type of gas detector is able to pick up leaks of gas, or anything else and has proved itself over time – more than 20 years – in African countries. General Monitors, acquired by MSA during 2010 and based in California, supplies these, especially in the Middle East where OGP projects are plentiful. Oliver told us that Floating Production, Storage and Offloading (FPSO) units (floating vessels used by the off- shore oil and gas industry for the production and processing of hydrocarbons, and for the storage of oil), partially owned by governments and other players such as Sonangol, in countries such as Angola, offer MSA opportunities to install and maintain safety equipment, as well as to train and certify the relevant staff on the vessels.
For more information contact : Colin Oliver, tel: +27 11 610 2600; email: Colin.Oliver@msasafety.com or go to: www.msasafety.com
5
Chemical Technology • May 2016
The potential of water re-use in shale gas bed
fracturing in South Africa
by Carl Schonborn, Pr Eng
New water treatment technologies and new applications of existing technologies are being developed and used to treat shale gas produced water. The treated water can be reused as fracturing make-up water, irrigation water, and in some cases even drinking water. New approaches and more efficient technologies are needed to make treatment and re-use a widespread reality.
T he drilling and hydraulic fracturing of a horizontal shale gas well may typically require 7,5 – 15 mil- lion litres of water [5], with about 12 million litres being most common. The volume of water needed may vary substantially between wells and the volume of water needed per metre of well appears to be decreas- ing as technologies and methods improve over time. Table 1: Estimated water needs for drilling and fracturing wells in some USA shale gas fields
fractures within the reservoir rock and heal after fracturing, thus preventing the fluids from flowing back to the well. There are two sources of water that emanate from the hydraulic fracturing of shale beds. Flowback water and Produced water. Flowback water is a water-based solution that flows back to the surface during and after the completion of fracturing. It consists of the fluid used to fracture the shale. The fluid contains clays, chemical additives, dissolved metal ions and total dissolved solids (TDS). Most of the flowback occurs in the first seven to ten days while the rest can occur over a three to four week time period. The volume of recovery is anywhere between 20 % and 40 % of the volume that was initially injected into the well, ie, 2,5 - 5 million litres of water. The rest of the fluid remains absorbed in the shale formation. Produced water , in contrast, is naturally occurring wa- ter found in shale formations that flows to the surface throughout the entire lifespan of the gas well. This water has high levels of TDS and leaches out minerals from the shale including barium, calcium, iron and magnesium. It also contains dissolved hydrocarbons such as methane, ethane and propane. Some of these stranded fluids may flow back to the well in very small volumes over an extended time span. By pursuing the pollution prevention hierarchy of ‘Reduce, Re-use, and Recycle’, statutory bodies are examining both traditional and innovative approaches tomanaging shale gas produced water. This water is currently managed through a variety of mechanisms, including underground injection, treatment and discharge, and recycling.
Volume of Drilling Water per well (l)
Volume of Fractur- ing Water per well (l)
Total Volumes of Water per well (l)
Shale Gas Field
Approximate Number of 40 000 (l) road tankers
Barnett Shale
1 500 000
8 700 000
10 200 000
250
Fayetteville Shale 230 000*
11 000 000
11 230 000
280
Haynesville Shale 3 800 000
10 000 000
13 800 000
350
Marcellus Shale 300 000*
14 400 000
14 700 000
370
* Drilling carried out with ‘mists’ (less water) or oil-based muds for deep horizontal well completions.
Table 1 presents estimated per well water needs for four shale gas fields in the United States of America. Froma paper, ‘Modern Shale Gas Development in the United States for the US Department of Energy by GWPC and ALL Consulting – Tulsa Oklahoma’ [1], there is discussion about the ultimate location of fracturing fluids after drilling and fracturing of a shale bed. Unrecovered fluids, if any, will be located in the natural shale bed pores and some will occupy the micro-pore space vacated by the gas that is produced. Also, some of the fracturing fluids remain stranded in
6
Chemical Technology • May 2016
WATER TREATMENT
While a TDS of 5 000 mg/l is the minimum threshold for a water to be considered brine, the typical range is 30 000 to 100 000 mg/l. In South Africa drinking water must meet the require- ments of SANS 241 [4], which specifies, amongst other constituents, a maximum allowable value in mg/l of Nitrate, N<11, Sulphate, SO 4 <250, Fluoride, F<300, Chloride, Cl<200 and Sodium as NA of about 10. Natural formation water has been in contact with the reservoir formation for millions of years and thus contains minerals native to the reservoir rock. The salinity, TDS, and overall quality of formation water vary by geologic basin. After initial production, produced water can vary from brackish to saline to supersaturated brine (50 000 mg/l to >200 000 mg/l TDS) [5], and some shale gas operators have reported TDS values greater than 400 000 mg/l. The variation in composition changes primarily with changes in the natural formation water chemistry. TDS concentration is calculated as the sum of the con- centrations for Na + , K + , Mg 2 + , Ca 2 + , Cl-, SO 2 -, TAL, NO 3 -, F-, PO 4 3 - and NH 4 + in a sample filtered through a 0,45 µm filter [6]. See Table 2 on page 8. One factor in shale gas water use is that operators need this water when drilling and hydraulic fracturing activities are occurring, requiring that the water be procured over a relatively short period of time, and these activities will occur year-round. Operators may need to store water for later use. At some point, the water that is recovered from a gas well makes a transition from flowback water to produced water. This transition point is sometimes identified according to the rate of return measured in m 3 /day and by looking at
The costs of transporting water from the source to the well site can quickly and dramatically exceed the simple cost of obtaining the water [2]. Regulation of impacts on water quality in South Africa In South Africa the National Water Act, No 36 of 1998, states in the preamble that one of the objects is: ”Recognising that the protection of the quality of water resources is necessary to ensure sustainability of the nation’s water resources in the interests of all water users.” [3] What this means is that hydraulic shale bed fracturing becomes a water use, thus requiring a water use license. The Act should be studied to understand the ramifica- tions in more detail, in particular: • Water use • Prevention and remedying effects of pollution • Determination of quantity of water which may be allo- cated by the responsible authority • Licences for use of water found underground on property of another person • Regulations on use of water • Controlled activity • Declaration of certain activities as controlled activities • Water classification. Water can be classified by the amount of TDS (Total Dissolved Solids) per litre: Fresh water < 1 000 mg/l TDS
Brackish water 1 000 to 10 000 mg/l TDS Saline water 10 000 to 30 000 mg/l TDS Brine > 30 000 mg/l TDS
7
Chemical Technology • May 2016
seek to manage produced water in a way that protects surface and ground water resources and, if possible, reduces future demands for fresh water. By pursuing the pollution prevention hierarchy of ‘Reduce, Re-use, and Recycle’, these groups are examining both traditional and innovative approaches to managing shale gas produced water. This water is currently managed through a variety of mechanisms, including underground injection, treatment and discharge, and recycling. Underground injection has traditionally been the primary disposal option for oil and gas produced water. Injection of the produced water is not possible in every play as suitable injection zones may not be available. Similar to a producing reservoir, there must be a porous and permeable formation capable of receiving injected fluids nearby. If not locally available, pipelines have been constructed to transport produced water to injection well disposal sites; this mini- mises trucking thewater. Treatment of produced water may be feasible through either self-contained systems at well sites, or commercial treatment facilities. As in underground injection, transporta- tion to treatment facilities may or may not be practical [10]. Re-use of fracturing fluids is being evaluated by operators to determine the degree of treatment and make-up water necessary for re-use [11]. The practical use of on-site, self- contained treatment facilities and the treatment methods employed will be dictated by flow rate and total water vol- umes to be treated, constituents and their concentrations requiring removal, treatment objectives and water reuse or discharge requirements. In some cases it would be more practical to treat the water to a quality that could be reused for a subsequent hydraulic fracturing job, or other industrial use, rather than treating to discharge to a surface water body or for use as drinking water.
Table 2: Typical TDS levels in some US produced water
Powder River CBM
1 200 mg/L
San Juan CBM
4 500 mg/L
Greater Green River
8 000 mg/L
Fayetteville Shale
25 000 mg/L
Barnett Shale
60 000 mg/L
Woodford Shale
110 000 mg/L
Haynesville Shale
120 000 mg/L
Permian Basin
140 000 mg/L
Marcellus Shale
180 000 mg/L
the chemical composition. Flowback water produces a higher flowrate over a shorter period of time, greater than 8m 3 /day. Produced water produces lower flow over a much longer period of time, typically from 0,5 to 6,5 m 3 /day. The chemical composition of flowback and produced water is very similar so a detailed chemical analysis is recommended to distinguish between flowback and produced water. As hydraulic fractionating water spends an increasing amount of time in the ground it transitions from fresh water to salty brine, dissolving salt compounds in the earth. Over time, volume decreases and TDS increases [7]. There are numerous shale gas bed areas in the USA and an equal number of water sources and regulations govern- ing the use of water for shale bed hydraulic fracturing. One in particular is the Susquehanna River Basin Commission located in the Marcellus Shale formation underlying an area from West Virginia in the south to New York in the north, approximately 250 000 km 2 [8]. Withdrawals for natural gas extraction in the Marcellus and Utica shales, however, are regulated separately [9]. States, local governments, and shale gas operators
8
Chemical Technology •May 2016
Table 3: Water treatment technologies and their relevance to composition of the water
SO 4 Cl TDS TSS Polymers
OH O/G DRO GRO TA HCO 3
Technology
Bacteria CH 3
TH Ca Mg Fe Ba St
API Separators
X
DAF
X
X
Activated Carbon
X
X
X
X
Nut Shell Filters
X
WATER TREATMENT
Clay Adsorbents
X
Chemical Oxidation
X
X
X
UV Disinfection
X
Biological
X
X
X
X
Air Stripper
X
X
Chemical Precipitation
X X X
X
X X X
Lime/Soda Softening X
X
X
X X X
X
Clarifiers
X
Settling Ponds
X
Ion Exchange
X X X
X
X X X
X X
Multi-Media Filtration
X
Membrane Filtration X
X
Sand Filters
X
X
Cartridge Filters
X
X
X X
Reverse Osmosis
X
X
X X X
Evaporation
X X X
X
X X X
X X
Steam Stripping
X
X
X
Acidification
X
X
9 SRBC, ―Aquifer Testing Guidance, Policy No. 2007-01 (December 5, 2007), http://www.srbc.net/programs/AQUIFER_TESTING_GUIDANCE. htm (accessed April 2010). 10 Harper, J. 2008. The Marcellus Shale – An Old “New” Gas Reservoir in Pennsylvania. Pennsylvania Geology. v 28, no 1. Spring 2008. Published by the Bureau of Topographic and Geologic Survey, Pennsylvania Depart- ment of Conservation and Natural Resources. 11 Railroad Commission of Texas (RRC). v2008.v Water Use in the Barnett Shale. http://www.rrc.state.tx.us/divisions/og/wateruse_barnettshale. html. Updated: June 30, 2008. Accessed: October 2008. 12 Modern Shale Gas Development in the United States for the U.S. De- partment of Energy by GWPC and ALL Consulting – Tulsa, Oklahoma, USA April 2009- Extensively quoted in this article by kind permission of GWPC –GroundWater Protection Council, Dan Yates – Associate Director. 13 Ewing, J. 2008. Devon Energy Corp. Taking a Proactive Approach toWater Recycling in the Barnett Shale. Presented at the Fort Worth Business Press Barnett Shale Symposium. February 29, 2008. In early 2009, studies were underway to determine the minimum quality of water that could successfully be used in hydraulic fracturing. If hydraulic fracturing procedures or fluid additives can be developed that will allow use of water with a high TDS content, then more treatment options become viable and more water can be reused. ■ in some cases even drinking water. This allows natural gas-associated produced water to be viewed as a potential resource in its own right [13]. Current levels of interest in recycling and reuse are high, but new approaches and more efficient technologies are needed to make treatment and re-use a widespread reality.
When the study, ‘Modern Shale Gas Development in the United States of America’ [12], was developed, there were plans to construct commercial wastewater treatment facilities specifically designed for the treatment of produced water associated with shale gas development in some loca- tions around the country. The success of such plants will be closely tied to the successful expansion of production in the various shale gas plays. New water treatment technologies and new applications of existing technologies are being developed and used to treat shale gas produced water. The treated water can be reused as fracturing make-up water, irrigation water, and References 1 Modern Shale Gas Development in the United States for the U.S. Depart- ment of Energy by GWPC and ALL Consulting – Tulsa Oklahoma, USA April 2009- Extensively quoted in this article by kind permission of GWPC – Ground Water Protection Council, Dan Yates – Associate Director. 2 Ibid 3 REPUBLIC OF SOUTH AFRICA, NATIONAL WATER ACT, Act No 36 of 1998 4 South African National Standard for DrinkingWater, SANS 241-1:Edition 1. 5 Satterfield, J., M. Mantell, D. Kathol, F. Hiebert, K. Patterson, and R. Lee. 2008. Chesapeake Energy Corp. Managing Water Resource’s Challenges in Select Natural Gas Shale Plays. Presented at the GWPC Annual Meeting. September 2008. 6 Geographical differences in the relationship between total dissolved solids and electrical conductivity in South 0African rivers, H van Niekerk; MJ Silberbauer; MMaluleke, Resource Quality Services, Department of Water Affairs 7 Water Management in Unconventional Natural Gas Exploration & Pro- duction, May 2011, Presentation, C Hunter Nolen 8 SRBC, 18 CFR 806.5, December, 2008
9
Chemical Technology • May 2016
Veolia pilots a process to optimise biogas production in Durban
Veolia’s scope of work for eThekwini Mu- nicipality included the supply, construction and commissioning of flow tanks, primary settling tanks, thickeners and digesters, as well as suction and delivery pipework, pumps, electrical power and control instru- mentation for the digestion plant. Veolia was also responsible for the mechanical and electrical design of the plant. Because of the varying waste
raw sewage will be pumped to two primary settlement tanks, in proportion to the flow- rate of the sewer feeding the tank. The primary settlement tanks form the starting point of a two-train treatment process. Raw sewage extracted from the Chatsworth sewer will feed train one, while the Jacobs and Badulla sewers will provide the feed for the second process train. Underflow from the primary settlement tanks will be transferred to thickeners, with each one receiving about 2,5 m 3 /day in intermittent feeds. Settled sludge from the thickener underflow will periodically be drawn off and fed into the 10 m 3 digesters. The biogas generated during this digestion phase will pass through a flow meter, gas analyser and a flame arrestor before being blown off into the atmosphere. The success of the pilot trial will be mea- sured according to the effective generation of this biogas via the anaerobic digestion relative to the wastewater feed flow rate from the different sources. For more information contact: Herbert Kleinhans, Project Engineer, Veolia Water Technologies South Africa on tel: +27 21 870 2752, or email herbert.kleinhans@veolia.com
Veolia Water Technologies, South Africa (Veolia) recently installed an anaerobic digestion pilot plant at eThekwini Water & Sanitation’s Southern Wastewater Treat- ment Plant in Merebank, Durban. The pilot trial is designed to test the digestibility of the domestic and industrial waste received by the plant. The plant was commissioned in the first quarter of 2016.
FOCUS ON WATER TREATMENT
composition and feed rates to the plant, piloting quality-specific treatment processes was re- quired to confirm the efficacy of the anaerobic digestion process to generate biogas from the cur- rent wastewater feed. The plant will concentrate sludge via settling and thick- ening followed by anaerobic digestion. Raw domestic and industrial sewage extracted for three sewers (Chatsworth, Ba- dulla and Jacobs) feeding the Municipal Wastewater Treatment Plant will be fed into three flow tanks (one tank for each inlet line) at a continuous flowrate of approximately 14 m 3 /h. From these flow tanks, 200 m 3 /day of
The sludge digestion pilot plant under construction, show- ing the two primary settling tanks in the foreground, two anaerobic digesters in the background and two thickener vessels (partially obscured) in centre of the plant.
Safe water guaranteed with new colorimetric analysing system Liquiline SystemCA80NO, the new colorimet- ric analysing system from Endress+Hauser, offers precise online monitoring of nitrite in drinking water, mineral water and raw water for food production. It enables plant manag- ers to comply with stipulated limit values and deliver detailed documentation.
Liquiline SystemCA80NO offers optimum support for manufacturers. It uses the stan- dardised colorimetric naphthylaminemethod following ISO 6777 and DIN EN 26777 — ensuring consistent comparability to lab measurements. The analyser also features detailed logbooks that provide continuous documentation of the nitrite values and en- able plant managers to prove compliance to water authorities. In drinking water treatment, dissolved nitrate is reduced to molecular nitrogen through a series of intermediate products. Liquiline System CA80NO monitors this denitrification process online and delivers measured values fast — helping to optimise the control of carbon dioxide dosing. It also supports plant operators in handling process disturbances promptly by advanced diagnos-
tics via remote access. The analytical system increases the safety of the denitrification process. Operating costs of a colorimetric analy- ser are dependent on the consumption of reagents and calibration standards over its lifetime. The Liquiline System is designed with highly precise dispensers for reagent dosing and an efficient cooling system. This guarantees reduced consumption and in- creased lifetime of the calibration standard. Automatic cleaning and calibration func- tions ensure that the analyser and its sample preparation and reagents work reliably and without manual intervention over a longer period of time. Maintenance tasks can be
carried out easily and with minimal tools, reducing maintenance costs and increasing process uptime. For more information contact: Jan Swart, Product Manager: Analytics on tel: +27 11 262 8000; email Jan.Swart@za.endress.com; or go to http://bit.ly/23gKM9C or www.za.endress.com
10
Chemical Technology • May 2016
WACKER Silicones – New applications for silicone films
by Glynnis Koch
German chemical company, WACKER, operates globally with a network of production sites spanning all key regions, in Europe, the Americas and Asia. WACKER’s silicone division is one of the largest silicone manufacturers worldwide. Its portfolio ranges from silicone fluids, emulsions, resins, elastomers and sealants to silanes, silane terminated polymers and pyrogenic silica.
W ACKER’s silicone products have applications in sectors such as, for example, chemicals, cos- metics, textiles, paper, electronics and medical technology. In 2015, the division generated around 37 % of the group’s sales. Founded in 1914, the Burghausen plant is WACKER’s principal production site and the larg- est chemical plant in Bavaria, employing almost 10 000 people in over 130 production units, on the 2,3 km ² site. All five of WACKER’s business divisions have operations at the Burghausen site, the integrated silicon-based produc- tion system being one of its key strengths. Five main raw materials form the basis for production: metallurgical-grade silicon, rock salt, ethylene, acetic acid and methanol. The portfolio of products manufactured at the site ranges from polysilicon and hyperpure silicon wafers to silicones, silanes and pyrogenic silicas, as well as dispersions and dispersible polymer powders, solid resins, fine chemicals and base materials for the chemical and biotechnical industries. The functional silicone fluids production plant was expanded in 2015, coming on stream in early 2016, and allowing WACKER to meet the rising global demand for ver- satile silicone fluids and emulsions in the coatings, paper, textile, cosmetics and personal care industries — areas where highly specialised functional silicone fluids serve as important intermediates. The plant combines the siloxane
precursor with other raw materials to produce functional silicone fluids. Another recent project involved upgrades to the facilities and technology of the application centre for silicone release coatings, the Dehesive ® Coating Centre. Ultrathin precision silicone film and dEAP technologies WACKER’s silicone films are 100 % silicone. Like all sili- cone rubber compounds, they are heat- and UV-resistant, flexible even at low temperatures and chemically inert. On account of their dielectric properties, silicone elastomers are categorised as electroactive polymers (EAPs). They are capable of responding to electrical stimulation under certain circumstances. This is the case, for example, when the elastomer is present as a non-conducting layer between two electrodes. Thanks also to their uniquematerial properties, precision silicone films are ideal for dielectric electroactive polymers (dEAP) technologies which began in the 1990s. At the time suitable materials and manufacturing processes were not available to produce dielectric films economically in the required quantity and of the desired quality. A process patented by WACKER now enables manufac- turers to begin mass-producing EAP components for the first time. It allows the manufacture of continuous films
12
Chemical Technology • May 2016
CORROSION & COATINGS
The pilot coater, which can coat solventless and emulsion coatings for most substrates, coats products under real conditions.
between 10 and 400 µm thick, the thickness fluctuating less than 5 % over the entire width. The exceptionally uniform, homogeneous films are made of addition-curing silicone rubber compounds without the use of solvents. They are manufactured under cleanroom conditions to eliminate any impurities. Coating the upper and lower surfaces of the silicone films with a flexible, electrically conductive material produces deformable capacitors. When a DC voltage is applied, the electrodes are attracted to each other electrostatically and compress the soft film material. The layer of elastomer material becomes thinner, and spreads out in the plane. The capacitor becomes flatter and wider overall. When the capacitor is discharged, the elasticity of the film causes it to return to its original shape. The entire process is silent and can be repeated as often as desired. Subtle nuances of such capacitance changes can be measured and thus used for sensory purposes, for example to display body movements. In actuators, they can control small movements, for example. This enables the design of very precise and efficient pumps, electric relays, artificial muscles, gripping devices and sound systems. If several hundred capacitors consisting of silicone film are placed on top of each other – referred to as stacks by experts – it is, with the aid of motion, even possible to generate electric-
Coated with conductible electrode layers, the silicone film constitutes a deformable capacitor (dEAP), if energised.
ity. In a project publicly funded by the German government, Bosch and WACKER have already successfully developed a generator that can use the upward and downward motion of ocean waves to generate electricity. The Danish company, LEAP Technology, and WACKER have been developing electronic components that can be incorporated discreetly into textiles and have already developed the first prototypes. LEAP Technology makes these out of Elastosil ® Film.
13
Chemical Technology • May 2016
Numerous properties of precision silicone films make them particularly interesting for the industry. Not only are they ex- tremely elastic, they also do not wear out. Tests have shown that Elastosil ® Film can survive over 10 million load cycles without the slightest fatigue. Silicone films hold back water but grant free passage to water vapour and certain gases. This gas permeability is highly selective: carbon dioxide, oxygen and water vapour pass through the silicone layer much faster than nitrogen. Elastosil ® Film could therefore serve as a membrane for removing a specific gas, such as carbon dioxide. Experts expect that, over the coming years, relays, switches and valves based on dielectric electroactive elastomers will come onto the market. Such components could, in the future, also give rise to new technologies, such as shape-changing touchscreens that the visually impaired could read with their hands. In the healthcare industry, for example, WACKER’s Silpuran ® Film is breath- able, biocompatible and easy to sterilise. These silicone films are therefore ideal for the manufacture of soft and flexible wound dressings. Simulation with silicone For pressure-sensitive adhesive (PSA) labels to function properly, the release coatings, adhesives and backing materials must be optimally matched and must suit the industrial processing conditions. WACKER tests this out in its new Dehesive ® Coating Centre. Not all labels are the same. While product information should permanently adhere to a shampoo bottle, the price
label on a water melon must peel off easily. Different ad- hesive mixtures make specific applications of self-adhesive materials possible, but also present the coatings industry with the challenge of providing a constant stream of new, modified silicone formulations for release liners. In addition, the substrate itself and subsequent process- ing play a role in deciding the composition of the release coating. For automated dispensing of labels, for example, it is important that the paper lattice between the individual labels – the matrix – can be pulled off easily without tearing or removing the labels from the backing material as well. Testing and optimising At the new coating centre in Burghausen, engineers work on a 380 m ² area to simulate industrial processing condi- tions for silicone release coating and to devise coating solutions to meet various requirements. The new centre combines a pilot coater, a test lab and a large selection of base papers and films used in the industry. This makes it possible to simulate and evaluate industrial processing conditions for silicone release coatings as realistically as possible, allowing the company to prepare new products for the market more quickly. Dr Hans Lautenschlager, who is in charge of technical support for silicone release coatings at WACKER, and his team are currently testing formulations for seven different substrates supplied by a US partner. There is a choice of 30 silicone polymers and five crosslinking agents available for the coating. Depending on their composition, the individual formulations vary with regard to flow properties, release force and curing rate. Dehesive ® silicone release coatings have been used in the paper coatings industry for many years to make self- adhesive materials that separate perfectly from release The requirements imposed on PSA labels vary considerably depending on the intended application and production method. Consequently, demands on the silicone release coating are high.
The mechanism for removing the adhesive from the silicone release coating forms the basis of tailor-made solutions.
Dr Robert Gnann took over as president of WACKER SILICONES, effective April 1, 2016. He succeeded Dr Christian Hartel, who was appointed to the WACKER Group’s Executive Board in early November 2015. Gnann comes to WACKER from Momentive Performance Materials, where, from 2008, he was responsible for the elastomers business unit and, in 2010, additionally took charge of the company’s European activities.
14
Chemical Technology • May 2016
CORROSION & COATINGS
WACKER’s Burghausen site, with its nearly 10 000 employees, is the largest chemical plant in Bavaria, Germany.
interact with the adhesive during storage. Long-term tests are also undertaken to ensure that the release coating still meets quality requirements after prolonged storage. To determine whether the curing reaction is complete, the coated substrate is placed in solvent, which dissolves out any uncured silicone. The amount of such uncured silicone is then measured analytically. As a result, the amount of platinum required can be determined precisely. Optimising the formulation can therefore reduce platinum consumption by as much as one third. New challenges Technical service engineers measure the coating’s release force electronically with the aid of a peelforce measuring device. Different tests show how the coating behaves at a peel angle of 90 º or 180 º, for example. The test results are illustrated graphically. Lautenschlager believes that, while the test results to date point the way ahead, they are by no means definitive. Release coatings thus require further research, so that shampoo, melons, and other products, will be optimally labelled in the future, too. ■
liners. The properties of silicone release coatings include the following: • Good coverage of the substrate’s surface • Minimal silicone consumption • No matrix breaks at high die-cutting speeds • Smooth, pin-hole free surfaces • Release values that do not change during storage • Ease of processing under widely various production temperatures and speeds • Application and adhesion to different kinds of substrates. At the pilot coater, a 1 to 1,3 µm layer is applied to the backing material and then dried in an airflotation dryer at 100 - 180 °C – depending on the material properties – for 1,2 to 18 seconds. Here, the WACKER experts simulate the customer’s industrial processing conditions exactly. The subsequent use of the release liner is also of great importance. In industrial labelling, a machine applies up to five labels per second to packaging – such as a shampoo bottle. The skill of the laminate manufacturer now lies in finding a compromise in the release force between the label and the release liner so that both matrix peeling and labelling run smoothly. Doublesided adhesive tape poses another challenge for laminate manufacturers. The release liner must feature two different release forces for the two sides, so that the adhesive tape peels off of the underside of the release liner first. This allows the doublesided adhesive tape to cleanly peel off for further processing. Testing with Xrays On a lab bench at the coating centre, a colour test provides information on the level of cover of a coating immediately after it has been applied. Xrays measure the thickness of the applied silicone release layer. After it has cured, the release coating still contains reactive groups that can • Custom controlled-release • Reproducible release force
WACKER expands Engineering Silicones laboratory in Dubai
The Dubai Technical Centre is a highly spe- cialised, applications-focused lab, supporting customers from the Middle East and Africa. The Engineering Silicones Lab is equipped to carry out necessary developments for Silicone Elastomers. The main applications are insula- tor coatings, mould-making, and baking trays.
The lab has ‘state-of-the-art’ mixing equipment for developing low viscosity Silicone Elastomers formulations. It also houses a Spray Chamber (see photo) which is a unique facility to support local customers in the electri- cal industry within the Middle East and Africa region.
15
Chemical Technology • May 2016
Pollution prevention potential of Hostacor ® AL corrosion inhibitor
Clariant, a world leader in specialty chemi- cals, says its recently-introduced Hostacor® AL water-dispersible corrosion inhibitor for use in the metalworking industry has been recognised by the US Environmental Protec- tion Agency (EPA) for its potential to reduce environmental pollution. The recognition is provided as part of the EPA’s Pollution Prevention (P2) Recognition Project within its New Chemicals Program (NCP), which is intended to encourage chemical companies to develop ‘greener’ chemistries. Unlike other corrosion inhibitors on the market, Hostacor AL contains no phospho-
rus, a potential nutrition source for microor- ganisms. Hostacor AL is entirely based on renewable feedstocks. Hostacor AL inhibits corrosion on steel and aluminum surfaces at low concentra- tions (well under 2,0 %) and pH values of around 9. At the same time, the component con- tributes to the lubrication of both metals. When used in aluminum cutting operations, it provides protection against staining in soft and hard water. It produces no lime soaps and has a very low foaming tendency. An ad- ditional benefit is that existing metal working
The programme includes a short course on ‘Formulating low VOC coatings using design-of-experiments (DoE)’, a presenta- tion on ‘Development of new thermosetting resins frompolyethylene terephthalate (PET) waste’ and ‘Co- and meko-free low VOC industrial coatings’; workshops on’ Novel multiphase acrylics for decorative coatings with extended open time’; ‘Multifunctional polymer for low VOC wood coatings’; ‘Novel acrylic epoxy hybrid waterborne dispersion cured with acrylic curing agents for low VOC coatings’; ‘The new silicone-hybrid is an innovative, more eco-friendly binder system delivering long-lasting top coats with superior surface properties’; ‘Modular binder systems for high-performance low VOC coatings’; and ‘Low to near zero VOC polyaspartics technology for on-site ap- plications’. EcoTain label after they have undergone a systematic, in-depth screening process using 36 criteria in all three sustainabil- ity dimensions: social, environmental and economic. EcoTain label-awarded products significantly exceed sustainability market standards, have best-in-class performance and contribute to sustainability efforts of Clariant and its customers. “There is a growing need in the metal- working industry for sustainable and multi- functional additives, especially for use in semisynthetic-based cutting and grinding fluids that are intended to machine light- weight materials. This is mainly driven by the demand from the automotive or avia- tion industry to reduce weight and increase energy and fuel efficiency,” says Ralf Zerrer, Head of Strategic Marketing & Innovation at Clariant’s Business Unit Industrial & Consumer Specialties. “Hostacor AL has an outstanding com- bination of excellent performance in terms of corrosion prevention and lubrication, together with high sustainability.” For more information contact: Stephanie Nehlsen at Clariant on tel: +41 61 469 63 63; or email: stefanie.nehlsen@clariant.com
FOCUS ON CORROSION & COATINGS
fluids for steel can be upgraded to machine alumi- num by post- add- ing Hostacor AL to the formulation. Since the be- ginning of this year, Hostacor AL has been car- rying Clariant’s EcoTain ® label, in recognition of its high level of sustainabil- ity. Products can only obtain the
EuropeanCoatings Technology Forum– Turning theory intopractice requirements swiftly. At the European Coat- ings Technology Forum, you will not only hear about new developments in low-VOC coatings, but you will also see how they can be used in practice. siasts and learn how they are tackling the challenges of developing low-to-zero-VOC coatings.”
Low and zero VOC Coatings - 08-09 June 2016, Berlin, Germany Sonja Specks, the Editor of ‘European Coat- ings Journal’ writes about the forthcoming conference. “The European Coatings Technology Forum conference on low VOC coatings is the fast- est way to address the challenges you face in low-VOC projects. It’s a brand-new event, designed specifically to address the needs of coatings experts working in R&D, appli- cations technology and quality assurance. Hands-on experience is the key to get- ting things done. Every day, you’re under pressure to develop high-performance low to zero VOC coatings for all kinds of applica- tion areas while trying to juggle the difficult demands of price constraints, customer wishes and legal requirements. No matter whether you work in develop- ment, applications technology or in quality assurance, you have to inject life into your projects so that you can meet customer
Find solutions to your problems: hands- on workshops in small groups will provide you with actionable solutions to the daily challenges you face in the lab. Hand-picked international experts will demonstrate the benefits of the latest innovations in low-VOC coatings and their practical applications. No lengthy company introductions, no presentation slides – the hands-on work- shops get straight to work on solving your problems. Challenge the experts – find out for your- self whether the innovative products being presented actually deliver the performance promised. This is a chance to get to grips with critical topics. Find inspiration – get away from the lab and spend time with other coatings enthu-
16
Chemical Technology • May 2016
Made with FlippingBook