Friday, March 1, 2019

CHEMICAL INDUSTRY / TECH SPECIAL.... Breakthrough technologies for chemicals


Breakthrough technologies for chemicals

For an industry as old as it is, the chemical industry continues to show a steady stream of innovations, especially in processes. This reinforces the adage that no technology is ever mature. Incremental improvements are ubiquitous in the industry and are aimed primarily at improving economics, cleaning up processes to reduce their environmental burden, to allow for exploitation of alternate raw materials or feedstock, and to offer improved performance or functionality. Product innovations are less common today in the core chemical industry, though the pharmaceutical and agrochemical industries are notable exceptions.
At the recent conference organised by the Indian Chemical Council (ICC), a presentation by Tecnon OrbiChem, a consultancy, highlighted the prospects for some ‘breakthrough’ technologies. A topic like this will have always have a fair bit of subjectivity, and runs the risk of being proven wrong!
A breakthrough technology is one that improves the economics of manufacture, uses new feedstock or lower amounts of existing ones, or produces less waste (i.e. is ‘greener’). It has the potential to fundamentally change the dynamics of business, relegating those who do not embrace the change to irrelevance or outright extinction. As the organic chemicals industry is built around a dozen or so key feedstock – the olefins (ethylene, propylene, C4 streams etc.), aromatics (benzene, toluene, xylene, etc.), methanol, synthesis gas etc. – technology developments in their manufacture will have great impacts down several value chains and are the focus of a fair bit of attention by researchers and businesses.
Find below a few technologies that have worked or could do so in the future.
Methanol from methane
Take methanol manufacture for a start. The classical route to this simplest of alcohols starts with a hydrocarbon feedstock – coal, petroleum fraction or natural gas – and involves its conversion first to synthesis gas or syngas (a combination of carbon monoxide and hydrogen); and then its conversion to methanol in a high pressure catalytic process. The economics are most attractive when natural gas is used as the primary raw material, though China has set up significant capacity in the recent past utilising indigenously available coal. The latter approach is much more capital expensive, but compensates to some extent in operating costs due the low price for coal. Importantly, it has a larger ecological footprint – especially in terms of CO2 emissions and water consumption.
A single step process for converting methane (the primary component of natural gas) directly to methanol using a partial oxidation process could have the potential to significantly alter the economics of methanol production by lowering capital costs, and could greatly expand the use of methane as an energy source. Several attempts have been made in this direction, but still suffer from low yields of methanol (about 5%). If this technology were to be successful, it will have wide ramifications, including by providing a route to end methane flaring (which accounts for about 2% of global CO2 emissions). Cheap methanol can find broader use as a blend in automotive fuel, serve as a substitute for LPG (when converted to dimethyl ether), and even be converted to olefins through well-established methanol-to-olefin (MTO) technologies.
Ethylene from shale gas
The availability of ‘wet’ shale gas – containing significant quantities of ethane and propane – in abundance in North America has fundamentally altered the business of petrochemicals manufacture. Its utilisation as a feed for ‘cracking’ can be termed as a disruptive technology already having a wide impact. Nearly 10-mtpa of additional ethylene capacity is expected in the US based on shale gas, at a cost structure comparable to that enjoyed by crackers in Saudi Arabia operating on cheap natural gas.
The economics of this ethylene is well insulated from oil markets and the competitive advantage gets better at high oil prices.
Oxidative coupling of methane to ethylene
Over the last decades, significant efforts have been made in research and industry to enable the direct, catalytic conversion of methane to ethylene in the presence of oxygen, known as Oxidative Coupling of Methane (OCM). But the developed catalysts did not meet the minimum requirements for commercial-scale applications. More recently, however, Siluria Technologies, a San Francisco-based start-up, has claimed the development of an economically viable OCM catalyst and related reaction technology that overcomes the limitations of formerly failed developments. A 400-tpd (tonnes per day) pilot plant based on its technology has been in operation since 2014 in the US, and the company has teamed up with engineering giant, Linde, to take it to market.
The research interest in OCM and the number of patents filed have both slowed down in recent times, indicative of the challenges associated with activating a relatively inert molecule as methane and selectively converting it to a reactive olefin like ethylene. But if the technology sees a breakthrough, it could afford another option to cheap ethylene and downstream derivatives.
Ethanol to ethylene
While this technology was practiced for some time, even here in India, it lost favour with the advent of steam cracking technologies. The economics are obviously determined by the price of ethanol, which is nowadays being set by its value as an oxygenate in gasoline. The scale of operations has historically been smaller than for crackers, and this has further handicapped the process. The only exception is when the ethylene so produced is able to command a premium over that produced through conventional cracking.
This is the case with India Glycols Ltd.’s route to monoethylene glycol, which is produced from ethylene derived from bio-ethanol (from sugarcane molasses). The product has found a niche outlet for making partially renewable polyethylene terephthalate resins, which a handful of companies, including Coca-Cola, are purchasing to buttress their ‘green’ credentials.
In the US, speciality chemicals producer Croda is now offering bio-based surfactants by combining ethylene oxide (made from corn-derived ethanol) with palm-based fatty alcohols.
But in the absence of the price premium on the bio-ethylene or its derivative, the economics of ethanol conversion to ethylene are not attractive.
On-purpose technologies for propylene
The shift to cracking of lighter feedstock has resulted in lower propylene yields (in relation to ethylene) and provided an incentive for several ‘on-purpose’ propylene production technologies, of which propane dehydrogenation (PDH) is most popular. Several units have been built, particularly in China, to feed polypropylene and C3 chemical value chains, and one is now being contemplated in India by the BASF-Adani joint venture to provide propylene for production of acrylics and oxo-alcohols.
Refineries in India are also investing in deep catalytic cracking technologies to raise propylene output to higher levels. BPCL, for example, is building a C3 chemicals complex based on propylene so produced, and several other refiners eager to diversify into petrochemicals are taking this approach as a first, relatively low-risk step into a new business.
Methanol-to-propylene (MTP) technologies are a little more exotic than the above two options to augment propylene output, but a handful of plants have been built in China, based on indigenous technology development efforts.
Waste to chemicals
There are several technologies being developed that use wastes – municipal, waste polymers etc. – as inputs. Pyrolysis technologies to produce ‘oils’ from waste thermoplastics, for instance, are now at an early stage of development, as a means to tackle the mounting problem of plastic waste. BASF, for example, is now ‘cracking’ small volumes of such ‘oils’ by blending them into naphtha crackers to produce olefins with a favourable carbon footprint, and offering it to the market with a greener tag. There is vast scope to expand such efforts in the transition to a circular economy, which will impact future demand for ‘new’ carbon feedstock.
Embrace the change … or else
These and several other technology development efforts will reshape the business of chemicals going forward. The winners will be companies that anticipate, lead or embrace the change. The losers will include those who stay mired in the present!

Ravi Raghavan
Chemical Weekly Issue date: 26th February 2019

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