CA3110379A1 - Remote utilities system using hydrogen peroxide and methods - Google Patents

Abstract

A system and process provide one or more utilities to a facility. In some examples, the facility is a natural gas wellhead separator shed. The process includes decomposing hydrogen peroxide over a catalyst into water and oxygen. The decomposition process creates heat, which can be used to heat the facility. The oxygen is optionally produced under pressure, and can be used as a replacement for other pressurized gasses.
Optionally, the system may generate electricity. Optionally, water produced in the process may be used for potable water, process water or to dilute a solution of hydrogen peroxide before it is decomposed. The system includes a hydrogen peroxide tank, a decomposition unit with a catalyst, a heat exchanger, optionally a steam knockout and optionally an electrical generator.

Description

REMOTE UTILITIES SYSTEM USING HYDROGEN PEROXIDE AND METHODS
FIELD
[0001] This application relates to systems and methods for providing one or more .. utilities (for example heat, water, oxygen, a pneumatic source or energy) to a remote and/or off-grid building or other facility.
BACKGROUND

[0002] Remote buildings are used in many industries. For example, in the oil and gas industry a separator shed may be located at a remote natural gas wellhead site. The separator shed contains a separation unit used to separate water and condensate from the natural gas produced at the wellhead before the natural gas is transferred to a pipeline connected to a processing facility. The separator shed requires one or more utilities, such as heat, water, a pneumatic source and electrical power, to operate the equipment and optionally to support workers at the site. However, the separator shed might not be near an electrical power grid.

[0003] In some examples, solar panels as used to provide electrical power to a remote building. In the case of a separator shed, the separation unit divides the raw natural gas into two streams: fuel gas stream that is used to run pneumatic devices that control the systems in the separator shed, and a raw natural gas stream that goes directly into the pipeline for further processing downstream. The fuel gas is often an inconsistent mixture of gasses with varying concentrations of contaminants. The fuel gas contains methane that is used to provide heat through a catalytic heater. The fuel gas is also used as a pneumatic source, for example as instrument air. All sensors, switches and other equipment exposed to the fuel gas are made to operate in an explosive environment, but some risk of explosion remains. Further, the fuel gas and the exhaust from the catalytic heater create greenhouse gas emissions. The use of the fuel gas to provide utilities to the building therefore increases the carbon footprint of natural gas production.
INTRODUCTION

[0004] This specification describes a system and process for providing one or more utilities to a facility, which may be a remote and/or off-grid facility. In some examples, the Date Recue/Date Received 2021-02-25 facility is a well-head separator shed. However, the system and process may be adapted for use in other facilities of applications, for example wastewater treatment.

[0005] The process includes decomposing hydrogen peroxide over a catalyst into water and oxygen. The decomposition process creates heat, which can be used to provide space heat to the facility or heat for an industrial process. The oxygen is optionally produced under pressure, and can be used as a replacement for other pressurized gasses.
Optionally, hydrogen peroxide can also be used to produce electrical power, for example in a fuel cell, and/or heat or pressure created by decomposing hydrogen peroxide can be used to produce electrical power. Optionally, water produced in the process may be used for potable water, process water or to dilute a solution of hydrogen peroxide before it is decomposed.

[0006] The system includes a hydrogen peroxide tank, a decomposition unit with a catalyst, a heat exchanger and optionally a gas-water separator such as a steam knockout.
The heat exchanger may be connected to a radiator or forced air heating unit of a building. A
gas outlet from the system may be connected to an oxygen or pneumatic supply network. A
water outlet from the system may be connected to a water distribution system of a facility.
Optionally, the system also includes a fuel cell, for example a direct hydrogen peroxide fuel cell, a turbine, a compound steam engine or a thermoelectric module for generating electrical power.
BRIEF DESCRIPTION OF THE FIGURES

[0007] Fig. 1 is a schematic drawing of a utility system.

[0008] Fig. 2 is a cross section of a hydrogen peroxide decomposition unit of the utility system of Fig. 1.
.. DETAILED DESCRIPTION

[0009] Fig. 1 shows a utility system 10. The utility system 10 includes a supply tank 12. The supply tank 12 contains an aqueous hydrogen peroxide solution 14.
Optionally, the hydrogen peroxide solution 14 may have a concentration of 20-65%, or 25-50% by weight. Commercial grade hydrogen peroxide may have a concentration of 50-98%
as supplied in a tanker truck. Commercial grade hydrogen may be diluted for use in the system 10. Optionally, water for dilution may be produced by the decomposition of hydrogen peroxide in the system 10. In some examples, the tank 12 holds 50% hydrogen peroxide, which may have been diluted from a higher concentration supplied by a tanker truck.

Date Recue/Date Received 2021-02-25 Optionally, the hydrogen peroxide 14 may be diluted further, for example to 25-30%
hydrogen peroxide, for use in a fuel cell 42 or decomposition chamber 22.
However, storing the hydrogen peroxide at a concentration of 50% or more reduces the size of tank 12 and prevents freezing in cold climates.

[0010] An outlet from the supply tank 12 leads to a pump 16. The pump may be, for example, a gear pump, a displacement pump or a peristaltic pump. The pump 16 provides pressurized hydrogen peroxide solution 14 at an outlet of the pump 16. The pressure is sufficient to produce a mist or aerosol as the hydrogen peroxide solution passes through a nozzle (to be described further below). For example, the outlet pressure of the pump 16 may be in the range of 2-41 bar (30-600 psi) or 14-41 bar (200-600 psi).
Optionally, a check valve 18 is provided to prevent backflow of hydrogen peroxide solution 14 to the pump 16.

[0011] The hydrogen peroxide solution 14 is sent under pressure to a decomposition unit 22. Further details of the decomposition unit 22 are shown in Fig. 2. The decomposition unit 22 includes a reaction chamber 26, which may also serve as the main structural body of the decomposition unit 22. In the example shown, the reaction chamber 26 is an assembly of multiple pipe segments with caps at each end. In other examples, the reaction chamber 26 may be made from a single section of pipe with caps at each end. In an example, the inside diameter of the reaction chamber 26 is in the range of 15 to 80 mm and the length of the reaction chamber is in the range of 10-30 cm long. The reaction chamber 26 may be made, for example, of steel. Inlet tubing 56 to the decomposition chamber may be 1/4" (6 mm) stainless steel tubing. Outlet tubing 60 may be 3/8" (9 mm) stainless steel tubing.

[0012] The decomposition unit 22 contains a nozzle 24 at one end of the reaction chamber 26. The nozzle 24 produces a spray or aerosol of aqueous hydrogen peroxide inside the chamber 26. The chamber 26 also contains a catalyst 28. The catalyst 28 may include one or more catalytic materials such as manganese dioxide, lead dioxide, silver or platinum. Optionally, the catalytic material may be provided on a supporting material. The catalyst 28 is preferably configured to provide a high surface area.

[0013] A pre-heat element 20 is used to warm the decomposition unit 22 before a cold start. The pre-heat element 20 warms the outside of the decomposition unit 22, which thereby warms the inside if the decomposition unit 22 and the catalyst 28 within it. A
hydrogen peroxide pre-heat unit 54 pre-heats the hydrogen peroxide flowing though inlet tubing 56 to the decomposition unit 22. Optionally, the hydrogen peroxide pre-heat unit 54 can be made by passing some of the inlet tubing 56 along the surface of the decomposition Date Recue/Date Received 2021-02-25 unit 22. In this way, the hydrogen peroxide is warmed by the decomposition unit 22 before entering the decomposition unit 22. The pre-heat element 20 may be operated from a battery, which optionally may be charged by electricity generated by the system 10. The pre-heat element 20 may warm the decomposition unit 22 to a temperature in the range of 70-250 C. During normal operation, the decomposition unit 22 may operate at a temperature in the range of 150-250 C.

[0014] In an example, the catalyst 28 comprises silver, for example in the form of nanoparticles, wires, powder or mesh. Alternatively or additionally, the catalyst 28 may comprise platinum, iridium, platinum-tin or manganese oxides. Optionally, the catalyst 28 may be coated on another material, such as silica, alumina or supported by another material such as stainless steel mesh. Some examples of catalysts are described in US
Patent Numbers 3, 363,983; 3,488,962; and, US 3,560,407. The catalyst 28 is located in the reaction chamber 26 downstream of the nozzle 24.

[0015] When droplets of hydrogen peroxide solution 14 contact the catalyst 28, the hydrogen peroxide decomposes into water and oxygen gas in an exothermic reaction. As a result of the heat of reaction, the water and oxygen are heated. Typically, the water is produced as steam. An outlet 30 at the downstream end of the reaction chamber 26 allows oxygen and steam to leave the reaction chamber 26. However, the outlet 30 is a relatively small opening with a size selected to produce an effective residence time and backpressure in the reaction chamber 26 such that the hydrogen peroxide is essentially completely decomposed. Oxygen and steam (oxygenated steam) are emitted under pressure from the decomposition unit 22.

[0016] The system 10 is generally open from the outlet 30 of the decomposition unit 22 through a heat exchanger 32 and knockout 34. This reduces the possibility for blockages although pressure relief valves 42 are added at various locations where there is a possibility of pressure buildup or blockage.

[0017] The decomposition chamber 22 turns hydrogen peroxide 14 into oxygenated steam, which is converted into oxygen and condensed water. There is a possibility of some hydrogen peroxide vapour being emitted from the decomposition chamber 22, particularly after a cold start up of the system 10. In tests, there was less than 1%
hydrogen peroxide in the condensed water even on a cold start up. However, the condensed water may require treatment before being used for a purpose that will not tolerate a small amount of hydrogen Date Recue/Date Received 2021-02-25 peroxide. For example, sodium bicarbonate may be added to the condensed water, followed by heating the water.

[0018] The pump 16 has a variable frequency drive (VFD) and is controlled by a programmable logic controller (PLC). The PLC is connected to temperature and pressure .. sensors associated with the decomposition unit 22 and a temperature sensor (which may be part of a thermostat) associated with a building or other unit being heated by the heat exchanger 32. The PLC may have a variety of programmed control routines. For example, in a standby routine, the PLC operates the pump 16 primarily considering the temperature sensor associated with the decomposition unit 22. In the standby mode, the PLC
operates the pump 16 to provide a hydrogen peroxide intermittently or at a low flow rate to maintain a minimum standby temperature of the decomposition unit 22. In a heating mode, the PLC
operates the pump 16 at a variable speed, or at one of a set of pre-determined speeds, according to the demand for heat as determined by a temperature sensor or thermostat in communication with the heat exchanger 32. In pneumatic oxygen mode, the PLC
operates the pump 16 when the pressure sensor associated with the decomposition chamber (i.e.
upstream of valve 50) indicates that the pressure in the decomposition chamber is below a minimum pressure threshold. The minimum pressure threshold may be sufficient for an upstream tank 64 to recharge an oxygen storage tank 52. The pneumatic oxygen mode may have a single pre-determined speed for the pump 16 determined to match, or exceed by a factor of safety, the maximum expected demand for oxygen. The PLC may operate in heating mode and pneumatic oxygen mode at the same time by selecting the higher pump speed required by either mode. When neither the heating mode nor the pneumatic oxygen mode requires the pump 16 to operate, the PLC may revert to standby mode.

[0019] Returning to Fig. 1, the outlet 30 of the decomposition unit 22 leads to a heat exchanger 32. The heat exchanger 32 may contain one or more lengths of pipe that the oxygen and steam flow through. A second fluid flows around these tubes and becomes heated. In one example, the heat exchanger 32 may be a shell and tube heat exchanger and the second fluid may be water connected to a hydronic heating system. In another example, the heat exchanger 32 may be a coil or radiator and the second fluid may be air.
The air may be heated by the natural convection of air past the heat exchanger 32.
Alternatively, the heat exchanger 32 may be placed within a forced air heater or furnace that blows air past the heat exchanger 32 and into the room. For operation in summer months, Date Recue/Date Received 2021-02-25 the heat exchanger may be connected to a vent system to channel heat outdoors or located near an open window to avoid overheating a building.

[0020] The steam may be sufficiently cooled in the heat exchanger 32 to condense into water. Liquid water may be drained from the heat exchanger 32, and the heat exchanger 32 may have a pressurized oxygen outlet. Alternatively, an outlet of the heat exchanger 32 is connected to a gas-liquid separator 34, alternatively called a steam knockout. Liquid water is separated from the oxygen gas and flows periodically through an automated drain valve 36 to a water tank 48. Water may be taken from the water tank 48 for use, for example, as potable water, process water or to dilute incoming hydrogen peroxide.
The water may be further treated if necessary. Tubing in the heat exchanger 32, between the decomposition unit 22 and the heat exchanger 32 and between the heat exchanger 32 and a gas-liquid separator 34, may all be sloped downwards so that all condensed water flows to the gas-liquid separator 34.

[0021] Oxygen leaves the gas-liquid separator 34 for use through a first pressure regulator 38 or through a valve 50 to a storage tank 52. Oxygen may be stored in the storage tank 52 and drawn when required for use through a second pressure regulator 68.
Optionally the second pressure regulator 68 is set to a lower pressure (i.e.
400-750 kPa) than the first pressure regulator 38 (i.e. 2000 kPa or more). The storage tank 52 is kept within a pre-determined range of pressures by regulating valve 50 through a signal from a tank pressure sensor 62. When the tank pressure sensor 62 detects pressure within the tank at a lower threshold, the valve 50 is opened to release pressurized oxygen from upstream parts of the system 10 until an upper threshold of tank pressure is reached.
An upstream oxygen storage tank 64 may be provided upstream of valve 50 to provide a sufficient volume of oxygen to recharge storage tank 52 without waiting for new oxygen to be produced from the decomposition unit 22 (which is triggered by low pressure upstream of valve 50).
Pressurized oxygen 40 is thereby provided for use as a pneumatic source, for example, as instrument air. A pressure relief safety valve 42 vents excess oxygen from upstream of valve 50 if required to protect upstream equipment. A dryer 66, or a filter such as a hydrophobic membrane filter, may be placed upstream of the storage tank 52 to remove residual humidity from the oxygen 40.

[0022] Optionally, the system includes hydrogen peroxide fuel cell 42, for example a direct hydrogen peroxide fuel cell, to produce electricity. The fuel cell 42 is connected to the tank 14 to receive hydrogen peroxide 12. The fuel cell 42 produces electricity and emits Date Recue/Date Received 2021-02-25 oxygen 44 and water 46. The oxygen 44 may be vented or, if produced at pressure, used as an additional pneumatic source. The water 46 may be sent to the water storage tank 48 for use or disposal.

[0023] In another option, a turbine or compound steam engine between the outlet 30 of the decomposition unit 22 and the heat exchanger 32 is used to create electricity. The pressure in the decomposition unit 22 is higher than in the rest of the system due to steam expansion. The steam expansion may be used to drive the turbine or compound steam engine. Preferably, a by-pass is provided around the turbine or compound steam engine to selectively allow the outlet 30 of the decomposition unit 22 to be connected directly to the heat exchanger 32.

[0024] In another option, a thermoelectric generator (alternatively called a Seebeck generator) is used to create electricity. The decomposition unit 22 is used as the heat source.
The decomposition unit 22 may be wrapped, for example with copper or aluminum, for heat transfer and to provide a generally flat surface with a larger surface area than the .. decomposition unit 22. One or more thermoelectric modules are mounted on the decomposition unit 22, or the copper or aluminum wrapping. A heat sink or radiator is added to the cold side of the thermoelectric module. The heat sink may be cooled, for example, by natural convection of air, forced flow of air i.e. from a fan, or water circulated, for example, from the water tank 48. In some examples, the heat sink is a finned copper or aluminum block.

[0025] The system 10 may be combined with a natural gas wellhead separator shed.
The heat exchanger 32 of the system 10 may be located inside of the shed. Air passes over the heat exchanger 32 by natural convection to provide space heating, i.e.
heating the air inside of the separator shed. Pressurized oxygen from the system is used to replace pressurized fuel gas as a pneumatic source, i.e. for instrument air.
Optionally, the tank 12 may be connected to a fuel cell, for example a direct hydrogen peroxide fuel cell, to produce electricity for use in the separator shed. Alternatively, another means of generating electricity describe herein may be used.

[0026] The use of hydrogen peroxide reduces the emissions of greenhouse gasses from the wellhead separator shed. Even when greenhouse gas emissions resulting from the production and transportation of hydrogen peroxide are accounted for, the system described herein may result in an 85% or greater reduction in greenhouse gas emissions from the separator shed.

Date Recue/Date Received 2021-02-25

[0027] The system may also be used to provide one or more utilities to another facility. For example, the system may be combined with a wastewater treatment, facility, a greenhouse or a fish farm. Air is frequently blown into aerators in water tanks to oxygenate the water. The system 10 produces pressurized oxygen that may be blown into the aerators.
In some examples, electrically powered pumps are not required and the oxygen gas produced in the system oxygenates the water more effectively than air.

Date Recue/Date Received 2021-02-25

Claims (6)

CLAIMS:
We claim:

1. A system for providing a utility to a facility comprising, a hydrogen peroxide tank;
a decomposition unit with a catalyst;
a heat exchanger; and, an oxygen outlet, wherein the heat exchanger is in communication with a heating unit in a room of the facility and/or the oxygen outlet is in communication with a pressurized gas system of the facility.

2. The system of claim 1 further comprising a fuel cell connected to the hydrogen peroxide tank, a turbine or compound steam engine downstream of the decomposition unit, or a thermoelectric module connected to the decomposition unit, to generate electricity for use in the facility.

3. The system of claim 1 wherein the facility is a natural gas wellhead separator shed.

4. The system of claim 1 wherein the oxygen outlet is connected to an aerator to oxygenate water.

5. A process for providing a utility to a facility comprising the steps of, decomposing hydrogen peroxide over a catalyst into water and oxygen;
using heat produced by the decomposition for space heating in the facility;
and, using oxygen produced in the decomposition for process air, a pneumatic source, instrument air or water oxygenation at the facility.

6. The process of claim 5 comprising producing electricity in a hydrogen peroxide fuel cell, by steam expansion, or by heat differential.