Kevin Salmon Lecture

THE BIOTECHNOLOGY OF INDUSTRIAL ETHANOL PRODUCTION

ETHANOL

  • Ethanol belongs to the Family of Alcohols: These are organic chemical compounds composed of carbon , hydrogen, and oxygen. With the characteristic Hydroxyl –OH Functional group. The family of these alcohols vary in chain length .

  • Typically ; CH(3)-(CH(2))n-OH (e.g., are methanol n=0, ethanol n=1, and Butanol n=3).

  • Ethanol typically is a Biofuel & a renewable fuel (Think of Biofuels as -From something once alive. Think of Renewable as quickly replenish-able).

  • Ethanol (CH3-CH2OH): A clear, colourless, flammable oxygenated hydrocarbon.

  • Ethanol is typically produced chemically from ethylene, or biologically from fermentation of various sugars from carbohydrates found in agricultural crops and cellulosic residues from crops or wood.

  • It is used as a gasoline octane enhancer and oxygenate (blended in proportions of 10 to 85 percent ethanol ) 10% most common.

  • In the high concentrations (eg E-85) The vehicles must be specially designed to run on this fuel.


HOW DOES ITS ENERGY CONTENT (in BTU) STACKS UP AGAINST OTHER FUELS?

**Btu is an imperial unit of energy — British Thermal Unit.

  • Electricity: 3,412 Btu/kilowatt-hour

  • Natural Gas: 1,031 Btu/cubic foot

  • Kerosene(or No.1 Fuel Oil) : 135,000 Btu/gallon

  • Gasoline: 120,215 Btu/gallon

  • Ethanol: 80,430 Btu/gallon

  • Methanol: 61,225 Btu/gallon

  • Diesel (or Fuel Oil No.2): 138,690 Btu/gallon

  • LPG (Propane): 91,330 Btu/gallon

  • Wood: 20 mill Btu/cord.(Cord is unit of measure for wood)


ETHANOL AS TRANSPORTATION FUEL (PROS)

  • Being an Oxygenated molecule it leads to cleaner burning and produces more environmentally friendly emissions from automobiles.(less carbon monoxide , soot etc.)

  • It is renewable.

  • It replaces expensive petroleum fuels, a particularly welcomed benefit to countries whom are not producers of these fuels-in times of high fuel prices.

  • It is an octane enhancer(it helps to increase the Octane number of the gasoline)

  • The Ethanol portion of the fuel , is typically at a purity of 99.5% Alcohol and 0.5% water.

  • It has antifreeze properties- which makes it beneficial as well for severe winter conditions.


BUT IT ALSO HAS PROBLEMS (CONS)

  • It Has a tendency to absorb water.

  • When it absorbs water …at a certain point it becomes immiscible with the petrol and forms a separate aqueous phase in the fuel…..it drops out of the fuel.

  • Water absorbed by the fuel , pulls the ethanol out of the fuel and causes reduction in octane


OCTANE

  • A fuel Quality requirement/Specification, that is important to Internal Combustion Engines.

  • Fuels are tested and assigned an Octane Number.

  • In Jamaica E-10 87 Gasoline has an Octane index of 87 Octane. While E-10 90 has octane number Index of 90.

  • Octane Index = (Motor Octane + Research Octane)/2


WHAT REALLY IS OCTANE?

Octane number, also called Antiknock Rating, measure of the ability of a fuel to resist knocking when ignited in a mixture with air in the cylinder of an internal-combustion engine. The octane number is determined by comparing, under standard conditions, the knock intensity of the fuel with that of bends of two reference fuels: iso-octane, which resists knocking, and heptane, which knocks readily. The octane number is the percentage by volume of iso-octane in the iso-octane-heptane mixture that matches the fuel being tested in a standard test engine.


BRIEF HISTORY OF FUEL ETHANOL IN JAMAICA

In 1984, ethanol was included in a list of commodities for which duty-free access to the United States was allowed under the Caribbean Basin Initiative (CBI). The then stated intention of the U.S legislation was to facilitate Caribbean economic development by allowing duty-free access to the U.S for certain commodities produced in the Caribbean, provided that there was at least 35% value added to the commodity within the Caribbean. This meant that Caribbean ethanol can enter the United States without paying the present US$0.54 gallon import duty.


JAMAICA’S ETHANOL OVER THE YEARS

To ensure an adequate supply of Caribbean sourced feedstock, two initiatives were taken. In 1985, PEL's parent corporation, the Petroleum Corporation of Jamaica (PC acquired the Bernard Lodge Sugar Factory which was slated for closure. The factory was rehabilitated where fermentation and distillation facilities were installed with the capacity to produce some 15 million gallons of hydrous ethanol each year for use by the PEL facility.


In 1986, the CBI legislation was modified to require more CBI sourced feedstock than Jamaica could produce. PEL then identified a recently closed sugar factory at Libertad in Belize, with a capacity similar to that at Bernard Lodge, and having access to abundant sugar cane production capacity. PEL leased the Libertad factory for five years initially with a purchase option, and undertook a program of growing sugar cane and making high grade molasses. The operation commenced in 1989 and continued until 1997.


Originally at PEL, the feedstock was processed in dehydration facility consisting of two plants with a combined capacity of 52 million gallons of ethanol per year. The first plant, purchased from Conger in Brazil, was installed in 1985, and had an annual capacity of 10 million gallons. The second plant, purchased from APV in the United States, was installed in 1986 and had a capacity of 42 million gallons per year. Both plants have similar operating condition using azeotropic distillation.


REHABILITATION PROJECT
With the USA market for ethanol growing significantly in 2004 and with new and more aggressive Renewable Fuels Standards (RFS), the market was poised for continued growth in the future. Additionally, in 2004 the quota for ethanol imports from CBI countries into the USA market had been below target by more than 50%.
As a result, PEL sought to identify reliable sources of feedstock at competitive prices in order to economically rehabilitate the dehydration plant. Since Brazil was among the highest producers of alcohol worldwide, it was advantageous that PEL establish a strategic alliance with potential investors that would provide access to a reliable source of feedstock preferably from Brazil where there was an abundant supply of sugar cane.

In 2005 PEL and Coimex Trading Company established a partnership to secure the supply of hydrous alcohol from reliable producers, primarily in Brazil, at. competitive prices, then to dehydrate it into fuel ethanol at the PEL plant in Jamaica for an agreed processing fee, and for the partners to jointly market the finished product in the US for an acceptable margin. As part of the agreement between Coimex and PEL, Coimex financed the construction of a new 40 million US gallon per year ethanol dehydration plant and provided services related to the procurement of feedstock and the sale of anhydrous ethanol jointly with PEL and the profits on the sale of anhydrous ethanol split on a 50/50 basis. The agreement with Coimex Trading Company expired on June 30, 2008 and the ethanol dehydration plant is now fully owned by PEL.

Petrojam Refinery, where the ethanol dehydration plant is located…


JAMAICA PLAN

Jamaica’s National Energy Policy (2009-2030)

ORIGINAL GOALS (3&7 Pertinent)

Goal 1:

Jamaican use energy wisely and aggressively pursue opportunities for conservation and efficiency.

Goal 2:

Jamaica has a modernized and expanded energy infrastructure that enhances energy generation capacity and ensures that energy supplies are safely, reliably, and affordably transported to homes, communities and the productive sectors on a sustainable basis.

Goal 3:

Jamaica realizes its energy resource potential through the development of renewable energy sources and enhances its international competitiveness, energy security, whilst reducing its carbon footprint.

Goal 4:

Jamaica’s energy supply is secure and sufficient to support long-term economic and social development and environmental sustainability

Goal 5:

Jamaica has a well-defined and established governance, institutional, legal and regulatory framework for the energy sector, that facilitates stakeholder involvement and engagement.

Goal 6:

Government ministries and agencies are a model/leader in energy conservation and environmental stewardship in Jamaica.

Goal 7:

Jamaica’s industry structures embrace eco-efficiency for advancing international competitiveness and moves towards building a green economy.


PROGRESS IN JAMAICA

Transport Sector

  • Jamaica established the National Vehicle Emissions Standards in 1996.

  • Jamaica phased out lead in gasoline during the period 1998 - 2000; only

  • Following phase out of lead based oxygen enhancer, this was replaced by Methyl Tert-Butyl Ether or MTBE.

  • This additive also turned out to be unsafe for health and the environment. It was as a result of this that ethanol entered the picture. with ethanol creating E10: a mixture of 10% ethanol and 90% gasoline. This phasing out of MTBE commenced in the third quarter of 2006

  • Today all of our Gasoline is E-10, and all our ethanol for Fuel is imported for E-10 production.


HOW IS FUEL GRADE ETHANOL PRODUCED?

  • Consider Hydrous (wet ethanol) and Anhydrous ethanol. Fuel requires Anhydrous Ethanol.

  • Anhydrous fuel ethanol starting from molasses can be produced through several combined routes by application of different technologies for:

    • fermentation, then distillation processes or,

    • fermentation then dehydration processes

  • Fermentation: continuous, batch, with or without yeast or vinasse(sludge) recirculation, using centrifuges or floculant yeast;

  • Distillation: vacuum or pressurised, in cascade, with or without side streams, and azeotropic distillation with an entrainer liquid.

  • Dehydration: molecular sieves (vapour permeation through membranes, with liquid or vapour phase feed)


ETHANOL AZEOTROPE

An azeotrope or a constant boiling point mixture is a mixture of two or more liquids whose proportions cannot be altered or chained by simple distillation. This happens because when an azeotrope is boiled, the vapour has the same proportions of constituents as the unboiled mixture. Because their composition is unchanged by distillation, azeotropes are also called (especially in older texts) constant boiling point mixtures.


AZEOTROPIC MIXTURES

For example, an ethanol-water mixture (obtained by fermentation of sugars) on fractional distillation yields a solution containing approximately 95% by volume of ethanol. Once this composition has been achieved, the liquid and vapour have the same composition, and no further separation occurs. A solution that shows large negative deviation from Raoult’s law forms a maximum boiling azeotrope at a specific composition. Nitric acid and water is an example of this class of azeotrope. This azeotrope has an approximate composition of 68% nitric acid and 32% water by mass, with a boiling point of 393.5K (120.4 degrees Celsius).


BREAKING THE AZEOTROPE

  • In these Ethanol –Water Azeotropic Mixtures it is typical to use what is called an entrainer. eg

    • Use of Benzene or

    • Use of Cyclohexane

  • To break the Azeotrope and allow for concentration of the Alcohol above the ~95% azeotropic limit.


THE MOLECULAR SIEVE OPTION

  • Dehydration of ethanol past 95 percent purity. It removes water from the ethanol/water vapor mixture that exits the rectification column to gain a dehydrated product. The dryness of this product can be tailored to meet specifications - anywhere from bioethanol with a water content of 0.5% to super dry ethanol for pharmaceutical or industrial applications with a water content of 0.01% or less.


ZEOLITE TYPE 3A

  • Molecular sieve acts as an effective absorbent for gases and liquids.

Abstract: There are several methods of separation of water from dilute ethanol solution. Among the separation methods, adsorption process would be a simple and economical alternative. Zeolite type 3A molecular sieves have he largest surface area and it possess selective micro-pores whereon, due to the small size of their pores, the water pores, the molecules are adsorbed while the ethanol molecules are excluded. In this paper, adsorption of water from liquid phase water-ethanol azeotrope using 3-A zeolite molecular sieve adsorbents was investigated. The objective of this work was to increase concentration of alcohol of liquid water-ethanol mixture (azeotrope). The experimentation was carried out.