Pentamethylheptane Blend for Cetane Reference Standard

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Solution Overview

Problem

The diesel fuel industry faces challenges in producing and validating Secondary Reference Fuel pairs due to the unavailability and high cost of the low Cetane Number Primary Reference Standard, 2,2,4,4,6,8,8-heptamethylnonane (HMN), necessitating a substitute that can be produced in large quantities at a reasonable cost to standardize T and U Secondary Fuel blends and CFR engines.

Innovation Solution

A composition comprising a blend of n-hexadecane with at least 99% purity and 2,2,4,6,6-pentamethylheptane (PMH) as the primary reference standard, which exhibits similar combustion properties to HMN, allowing for the determination of Cetane Number and Derived Cetane Number, and can be produced more cost-effectively in large quantities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If HMN is used as the primary reference standard, then measurement precision is maintained, but manufacturing cost and availability deteriorate

Engineering Contradiction:

ImproveCetane Number measurement accuracyVSAvoidproduction cost and availability

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent creates a substitute reference fuel (PMH blend) that copies the essential combustion characteristics of HMN. By using 2,2,4,6,6-pentamethylheptane as a surrogate for heptamethylnonane, the invention replicates the low-cetane reference standard functionality while avoiding the production and availability problems of HMN, thus maintaining measurement precision without the manufacturing constraints

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent employs a more economically producible reference fuel blend (PMH with n-hexadecane) that can be manufactured at lower cost and in greater quantities compared to HMN. This substitute reference standard provides the necessary low-cetane reference point without the high cost and limited availability of the original HMN standard

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If HMN is used as the primary reference standard, then Cetane Number scale accuracy is preserved, but productivity and operational efficiency deteriorate

Engineering Contradiction:

ImproveCetane Number scale accuracyVSAvoidoperational efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The PMH blend copy HMN's combustion behavior to maintain Cetane Number scale accuracy while enabling more efficient operations. The substitute reference fuel allows for easier production and validation of secondary reference fuel pairs, improving productivity without sacrificing measurement accuracy

Inventive Principle:

Principle #26Copying

3Ease of manufacture

If PMH is used as a substitute for HMN, then manufacturing cost and availability improve, but measurement precision may deteriorate

Engineering Contradiction:

Improveproduction cost and availabilityVSAvoidCetane Number measurement accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent modifies the reference fuel composition from HMN to PMH while adjusting the blend ratios with n-hexadecane to achieve the desired cetane number range. By changing the chemical parameters and combustion characteristics of the reference standard, the invention maintains measurement accuracy while improving manufacturability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent discards the problematic HMN standard and recovers its essential function using PMH as a substitute. The PMH blend recovers the low-cetane reference standard functionality that HMN provided, while avoiding HMN's production and validation issues

Inventive Principle:

Principle #34Discarding and recovering

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The use of PMH as a primary standard enables accurate determination of Cetane Number and Derived Cetane Number, eliminating the need for expensive HMN and simplifying the production and validation of Secondary Reference Fuel pairs, thereby standardizing diesel fuel combustion characteristics and reducing operational costs.

Implementation Method 1

Since diesels rely on compression ignition (no spark), the fuel must be able to auto-ignite... The operator of the CFR engine uses a hand-wheel to increase the compression ratio (and therefore the peak pressure within the cylinder) of the engine until the time between fuel injection and ignition is 2,407ms

Methodology Applied

Scientific EffectAdiabatic compression: Adiabatic Heating

Implementation Method 2

Cetane Number is a measure of the ignition performance of a diesel fuel compared to the ignition performance of reference fuels in a standardized engine test... Cetane Number is a measure of the fuel's delay of ignition time (the amount of time between the injection of fuel into the combustion chamber and the actual start of combustion of the fuel charge)

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentEP2970801B1Pentamethylheptane as a primary reference standard for cetane number

Publication Date: 2021.02.24 JOHANN HALTERMANN

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AI summary

A composition useful as a Reference Standard for measurement of Cetane Number or for use as a standard for determining a Derived Cetane Number consists essentially of a blend of n-hexadecane and 2,2,4,6,6-pentamethylheptane. The disclosed Reference Standards can be used directly as substitutes for blends of n-hexadecane and 2,2,4,4,6,8, 8-heptamethylnonane in ASTM D613-10a for determining Cetane Number, or in ASTM D6890, ASTM D7170 or ASTM D7668 to determine a Derived Cetane Number.