Frac water heater and fuel oil heating system

Abstract

An accessory heat exchanger unit for heating the fuel oil used by the frac oil heater system of the invention prior to combustion. The accessory heat exchanger unit receives and distributes the fuel oil through a plurality of heat exchanger tubes prior to directing the oil to the combustion chamber. The unit also includes an inlet for receiving heated treatment fluid from the frac water heater system of the present invention. The heated treatment fluid passes over the plurality of heat exchanger tubes of the accessory heat exchanger unit prior to being directed to the outlet of the accessory heat exchanger unit. By heating the fuel oil prior to combustion, the accessory heat exchanger unit greatly improves the viscosity and flow rate of the fuel oil, thereby allowing cheaper, less cold-tolerant grades of fuel oil to be used in extreme cold climates with no degradation in the operation of the frac water heater system of the present invention.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application is a continuation-in-part of U.S. patent application Ser. No. 12 / 352,505 filed on Jan. 12, 2009, which claims the benefit of and priority to U.S. Provisional Patent Application No. 61 / 078,734 filed Jul. 7, 2008, the technical disclosure of which is hereby incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Technical Field[0003]The present invention relates to an apparatus and method for heating fuel oil prior to combustion for subsequent use in heating a water or petroleum based fluid for injection into an oil or gas well or into a pipeline system. In particular, the present invention relates to an apparatus and method for pre-heating fuel oil prior to combustion to improve its viscosity and combustion characteristics in cold weather.[0004]2. Description of the Related Art[0005]It is common in the oil and gas industry to treat oil and gas wells and pipelines with heated fluids such as water and oil. For ex...

AI Technical Summary

Benefits of technology

The present invention is a new heat exchanger system that improves safety and efficiency. It includes a primary air system and a secondary air system to atomize and cool the fuel oil. The system has vents to reduce noise and prevent blowback events. It also has a hood mechanism for safer operation and an intake air muffler / silencer system to reduce noise. The system may include an accessory fuel oil heating system to heat the fuel oil prior to combustion. This improves fuel oil viscosity and flow rate, allowing cheaper grades of fuel oil to be used in extreme cold climates. The heated fuel oil is returned to the tank to preheat the fuel in the tank. Overall, the heat exchanger system improves safety and efficiency.

Problems solved by technology

Consequently, the construction of a permanent heating facility at the well site is not cost effective.

While gas-fired heat sources are adequate for performing many oil field servicing tasks, they exhibit a number of inherent drawbacks.

These inherent limitations significantly impact their effectiveness in performing certain heating operations at remote oil field work sites.

For example, frac jobs typically require the production of massive volumes of heated water.

While gas-fired heat sources are certainly capable of heating fluids such as water, they are poorly suited to heating in a timely manner large volumes of continuously flowing water in many commonly occurring climactic and atmospheric conditions.

Moreover, the logistics involved in conducting such heating operations at remote work sites negatively impacts the cost efficiencies of such a system.

Thus, gas-fired heating units often lack sufficient heating capacity to produce sufficient quantities of heated water rapidly enough for the required operation to be completed.

Needless to say, the logistics involved with providing additional holding tanks at the remote work site and the additional costs incurred in overheating or reheating the supply water negatively impacts the efficiency of the overall operation.

While the technique of overheating and stockpiling supply water can ameliorate some the shortcomings in the heating capacity of gas-fired heat sources, in certain circumstances (e.g., severely cold weather or high altitude) it is inadequate.

First, the temperature change requirement for the system is simply greater in colder weather.

Thus, it takes longer for the gas-fired heating unit to preheat the supply water.

The problem is further compounded by the fact that the stockpiled preheated water cools more rapidly in colder weather.

In addition, propane gas requires large and heavy high-pressure fuel tanks for its transport to remote sites.

The size of such high-pressure fuel tanks is, of course, limited by the size of existing roads.

Furthermore, there are several safety concerns which must be taken into consideration when using gas-fired heat sources.

An open flame at the well site poses a substantial risk of explosion and uncontrolled fire, which can destroy the investment in the rig and injure or even cost the lives of the well operators.

Moreover, open flame burners are particularly susceptible to erratic burning or complete blow-out in gusty wind conditions.

While safety concerns are of overriding importance, compliance with the no open-flame regulations requires additional time and expense to conduct heated fluid well treatments.

However, such remedies often come with significant increases in operating costs.

For example, using fuel additives or switching to more cold-tolerant grades of fuel oil noticeably increases the operating costs on a per gallon basis.

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